document_title: List of Nobel laureates in Physics

question_text: who got the first nobel prize in physics

root

text: List of Nobel laureates in Physics

text: Statistics[edit]

text: The first Nobel Prize in Physics was awarded in 1901 to Wilhelm Conrad Röntgen, of Germany, who received 150,782 SEK, which is equal to 7,731,004 SEK in December 2007. John Bardeen is the only laureate to win the prize twice—in 1956 and 1972. Maria Skłodowska-Curie also won two Nobel Prizes, for physics in 1903 and chemistry in 1911. William Lawrence Bragg was, until October 2014, the youngest ever Nobel laureate; he won the prize in 1915 at the age of 25.[5] Two women have won the prize: Curie and Maria Goeppert-Mayer (1963).[6] As of 2017, the prize has been awarded to 206 individuals. There have been six years in which the Nobel Prize in Physics was not awarded (1916, 1931, 1934, 1940–1942).

tag: p

text: Laureates[edit]

text:
Year
Laureate[A]
Country[B]
Rationale[C]

1901

Wilhelm Conrad Röntgen
 Germany
"in recognition of the extraordinary services he has rendered by the discovery of the remarkable rays subsequently named after him"[7]

1902

Hendrik Lorentz
 Netherlands
"in recognition of the extraordinary service they rendered by their researches into the influence of magnetism upon radiation phenomena"[8]

Pieter Zeeman
 Netherlands

1903

Antoine Henri Becquerel
 France
"for his discovery of spontaneous radioactivity"[9]

Pierre Curie
 France
"for their joint researches on the radiation phenomena discovered by Professor Henri Becquerel"[9]

Maria Skłodowska-Curie
 Poland
 France

1904

Lord Rayleigh
 United Kingdom
"for his investigations of the densities of the most important gases and for his discovery of argon in connection with these studies"[10]

1905

Philipp Eduard Anton von Lenard
 Austria-Hungary
 Germany
"for his work on cathode rays"[11]

1906

Joseph John Thomson
 United Kingdom
"for his theoretical and experimental investigations on the conduction of electricity by gases"[12]

1907

Albert Abraham Michelson
 United States
 Poland
"for his optical precision instruments and the spectroscopic and metrological investigations carried out with their aid"[13]

1908

Gabriel Lippmann
 France
"for his method of reproducing colours photographically based on the phenomenon of interference"[14]

1909

Guglielmo Marconi
 Italy
"for their contributions to the development of wireless telegraphy"[15]

Karl Ferdinand Braun
 Germany

1910

Johannes Diderik van der Waals
 Netherlands
"for his work on the equation of state for gases and liquids"[16]

1911

Wilhelm Wien
 Germany
"for his discoveries regarding the laws governing the radiation of heat"[17]

1912

Nils Gustaf Dalén
 Sweden
"for his invention of automatic valves designed to be used in combination with gas accumulators in lighthouses and buoys"[18]

1913

Heike Kamerlingh-Onnes
 Netherlands
"for his investigations on the properties of matter at low temperatures which led, inter alia, to the production of liquid helium"[19]

1914

Max von Laue
 Germany
"For his discovery of the diffraction of X-rays by crystals",[20] an important step in the development of X-ray spectroscopy.

1915

William Henry Bragg
 United Kingdom
"For their services in the analysis of crystal structure by means of X-rays",[21] an important step in the development of X-ray crystallography

William Lawrence Bragg
 Australia
 United Kingdom

1916
Not awarded World War I

1917

Charles Glover Barkla
 United Kingdom
"For his discovery of the characteristic Röntgen radiation of the elements",[22] another important step in the development of X-ray spectroscopy

1918

Max Planck
 Germany
"for the services he rendered to the advancement of physics by his discovery of energy quanta"[23]

1919

Johannes Stark
 Germany
"for his discovery of the Doppler effect in canal rays and the splitting of spectral lines in electric fields"[24]

1920

Charles Édouard Guillaume
  Switzerland
"for the service he has rendered to precision measurements in physics by his discovery of anomalies in nickel-steel alloys"[25]

1921

Albert Einstein
 Germany
  Switzerland
"for his services to theoretical physics, and especially for his discovery of the law of the photoelectric effect"[26]

1922

Niels Bohr
 Denmark
"for his services in the investigation of the structure of atoms and of the radiation emanating from them"[27]

1923

Robert Andrews Millikan
 United States
"for his work on the elementary charge of electricity and on the photoelectric effect"[28]

1924

Manne Siegbahn
 Sweden
"for his discoveries and research in the field of X-ray spectroscopy"[29]

1925

James Franck
 Germany
"for their discovery of the laws governing the impact of an electron upon an atom"[30]

Gustav Hertz
 Germany

1926

Jean Baptiste Perrin
 France
"for his work on the discontinuous structure of matter, and especially for his discovery of sedimentation equilibrium"[31]

1927

Arthur Holly Compton
 United States
"for his discovery of the effect named after him"[32]

Charles Thomson Rees Wilson
 United Kingdom
"for his method of making the paths of electrically charged particles visible by condensation of vapour"[32]

1928

Owen Willans Richardson
 United Kingdom
"for his work on the thermionic phenomenon and especially for the discovery of the law named after him"[33]

1929

Louis Victor Pierre Raymond, 7th Duc de Broglie
 France
"for his discovery of the wave nature of electrons"[34]

1930

Chandrasekhara Venkata Raman
 India
"for his work on the scattering of light and for the discovery of the effect named after him"[35]

1931
Not awarded

1932

Werner Heisenberg
 Germany
"for the creation of quantum mechanics, the application of which has, inter alia, led to the discovery of the allotropic forms of hydrogen"[36]

1933

Erwin Schrödinger
 Austria
"for the discovery of new productive forms of atomic theory"[37]

Paul Dirac
 United Kingdom

1934
Not awarded

1935

James Chadwick
 United Kingdom
"for the discovery of the neutron"[38]

1936

Victor Francis Hess
 Austria
"for his discovery of cosmic radiation"[39]

Carl David Anderson
 United States
"for his discovery of the positron"[39]

1937

Clinton Joseph Davisson
 United States
"for their experimental discovery of the diffraction of electrons by crystals"[40]

George Paget Thomson
 United Kingdom

1938

Enrico Fermi
 Italy
"for his demonstrations of the existence of new radioactive elements produced by neutron irradiation, and for his related discovery of nuclear reactions brought about by slow neutrons"[41]

1939

Ernest Lawrence
 United States
"for the invention and development of the cyclotron and for results obtained with it, especially with regard to artificial radioactive elements"[42]

1940
Not awarded World War II

1941
Not awarded World War II

1942
Not awarded World War II

1943

Otto Stern
 United States
"for his contribution to the development of the molecular ray method and his discovery of the magnetic moment of the proton"[43]

1944

Isidor Isaac Rabi
 United States
 Poland
"for his resonance method for recording the magnetic properties of atomic nuclei"[44]

1945

Wolfgang Pauli
 Austria
"for the discovery of the Exclusion Principle, also called the Pauli principle"[45]

1946

Percy Williams Bridgman
 United States
"for the invention of an apparatus to produce extremely high pressures, and for the discoveries he made there within the field of high pressure physics"[46]

1947

Edward Victor Appleton
 United Kingdom
"for his investigations of the physics of the upper atmosphere especially for the discovery of the so-called Appleton layer"[47]

1948

Patrick Maynard Stuart Blackett
 United Kingdom
"for his development of the Wilson cloud chamber method, and his discoveries therewith in the fields of nuclear physics and cosmic radiation"[48]

1949

Hideki Yukawa
 Japan
"for his prediction of the existence of mesons on the basis of theoretical work on nuclear forces"[49]

1950

Cecil Frank Powell
 United Kingdom
"for his development of the photographic method of studying nuclear processes and his discoveries regarding mesons made with this method"[50]

1951

John Douglas Cockcroft
 United Kingdom
"for their pioneer work on the transmutation of atomic nuclei by artificially accelerated atomic particles"[51]

Ernest Thomas Sinton Walton
 Ireland

1952

Felix Bloch
  Switzerland
 United States
"for their development of new methods for nuclear magnetic precision measurements and discoveries in connection therewith"[52]

Edward Mills Purcell
 United States

1953

Frits Zernike
 Netherlands
"for his demonstration of the phase contrast method, especially for his invention of the phase contrast microscope"[53]

1954

Max Born
 West Germany
"for his fundamental research in quantum mechanics, especially for his statistical interpretation of the wavefunction"[54]

Walther Bothe
 West Germany
"for the coincidence method and his discoveries made therewith"[54]

1955

Willis Eugene Lamb
 United States
"for his discoveries concerning the fine structure of the hydrogen spectrum"[55]

Polykarp Kusch
 United States
 Germany
"for his precision determination of the magnetic moment of the electron"[55]

1956

John Bardeen
 United States
"for their researches on semiconductors and their discovery of the transistor effect"[56]

Walter Houser Brattain
 United States

William Bradford Shockley
 United States

1957

Tsung-Dao Lee
 Republic of China
"for their penetrating investigation of the so-called parity laws which has led to important discoveries regarding the elementary particles"[57]

Chen Ning Yang
 Republic of China

1958

Pavel Alekseyevich Cherenkov
 Soviet Union
"for the discovery and the interpretation of the Cherenkov effect"[58]

Ilya Frank
 Soviet Union

Igor Yevgenyevich Tamm
 Soviet Union

1959

Emilio Gino Segrè
 Italy
 United States
"for their discovery of the antiproton"[59]

Owen Chamberlain
 United States

1960

Donald Arthur Glaser
 United States
"for the invention of the bubble chamber"[60]

1961

Robert Hofstadter
 United States
"for his pioneering studies of electron scattering in atomic nuclei and for his thereby achieved discoveries concerning the structure of the nucleons"[61]

Rudolf Ludwig Mössbauer
 West Germany
"for his researches concerning the resonance absorption of gamma radiation and his discovery in this connection of the effect which bears his name"[61]

1962

Lev Davidovich Landau
 Soviet Union
"for his pioneering theories for condensed matter, especially liquid helium"[62]

1963

Eugene Paul Wigner
 Hungary
 United States
"for his contributions to the theory of the atomic nucleus and the elementary particles, particularly through the discovery and application of fundamental symmetry principles"[63]

Maria Goeppert-Mayer
 United States
"for their discoveries concerning nuclear shell structure"[63]

J. Hans D. Jensen
 West Germany

1964

Nicolay Gennadiyevich Basov
 Soviet Union
"for fundamental work in the field of quantum electronics, which has led to the construction of oscillators and amplifiers based on the maser–laser principle"[64]

Alexander Prokhorov
 Soviet Union

Charles Hard Townes
 United States

1965

Richard Phillips Feynman
 United States
"for their fundamental work in quantum electrodynamics (QED), with deep-ploughing consequences for the physics of elementary particles"[65]

Julian Schwinger
 United States

Shin'ichirō Tomonaga
 Japan

1966

Alfred Kastler
 France
"for the discovery and development of optical methods for studying Hertzian resonances in atoms"[66]

1967

Hans Albrecht Bethe
 United States
"for his contributions to the theory of nuclear reactions, especially his discoveries concerning the energy production in stars"[67]

1968

Luis Walter Alvarez
 United States
"for his decisive contributions to elementary particle physics, in particular the discovery of a large number of resonance states, made possible through his development of the technique of using hydrogen bubble chamber and data analysis"[68]

1969

Murray Gell-Mann
 United States
"for his contributions and discoveries concerning the classification of elementary particles and their interactions"[69]

1970

Hannes Olof Gösta Alfvén
 Sweden
"for fundamental work and discoveries in magneto-hydrodynamics with fruitful applications in different parts of plasma physics"[70]

Louis Néel
 France
"for fundamental work and discoveries concerning antiferromagnetism and ferrimagnetism which have led to important applications in solid state physics"[70]

1971

Dennis Gabor
 Hungary
 United Kingdom
"for his invention and development of the holographic method"[71]

1972

John Bardeen
 United States
"for their jointly developed theory of superconductivity, usually called the BCS-theory"[72]

Leon Neil Cooper
 United States

John Robert Schrieffer
 United States

1973

Leo Esaki
 Japan
"for their experimental discoveries regarding tunneling phenomena in semiconductors and superconductors, respectively"[73]

Ivar Giaever
 United States
 Norway

Brian David Josephson
 United Kingdom
"for his theoretical predictions of the properties of a supercurrent through a tunnel barrier, in particular those phenomena which are generally known as the Josephson effect"[73]

1974

Martin Ryle
 United Kingdom
"for their pioneering research in radio astrophysics: Ryle for his observations and inventions, in particular of the aperture synthesis technique, and Hewish for his decisive role in the discovery of pulsars"[74]

Antony Hewish
 United Kingdom

1975

Aage Bohr
 Denmark
"for the discovery of the connection between collective motion and particle motion in atomic nuclei and the development of the theory of the structure of the atomic nucleus based on this connection"[75]

Ben Roy Mottelson
 Denmark

Leo James Rainwater
 United States

1976

Burton Richter
 United States
"for their pioneering work in the discovery of a heavy elementary particle of a new kind"[76]

Samuel Chao Chung Ting
 United States

1977

Philip Warren Anderson
 United States
"for their fundamental theoretical investigations of the electronic structure of magnetic and disordered systems"[77]

Nevill Francis Mott
 United Kingdom

John Hasbrouck Van Vleck
 United States

1978

Pyotr Leonidovich Kapitsa
 Soviet Union
"for his basic inventions and discoveries in the area of low-temperature physics"[78]

Arno Allan Penzias
 United States
"for their discovery of cosmic microwave background radiation"[78]

Robert Woodrow Wilson
 United States

1979

Sheldon Lee Glashow
 United States
"for their contributions to the theory of the unified weak and electromagnetic interaction between elementary particles, including, inter alia, the prediction of the weak neutral current"[79]

Abdus Salam
 Pakistan

Steven Weinberg
 United States

1980

James Watson Cronin
 United States
"for the discovery of violations of fundamental symmetry principles in the decay of neutral K-mesons"[80]

Val Logsdon Fitch
 United States

1981

Nicolaas Bloembergen
 Netherlands
 United States
"for their contribution to the development of laser spectroscopy"[81]

Arthur Leonard Schawlow
 United States

Kai Manne Börje Siegbahn
 Sweden
"for his contribution to the development of high-resolution electron spectroscopy"[81]

1982

Kenneth G. Wilson
 United States
"for his theory for critical phenomena in connection with phase transitions"[82]

1983

Subrahmanyan Chandrasekhar
 India
 United States
"for his theoretical studies of the physical processes of importance to the structure and evolution of the stars"[83]

William Alfred Fowler
 United States
"for his theoretical and experimental studies of the nuclear reactions of importance in the formation of the chemical elements in the universe"[83]

1984

Carlo Rubbia
 Italy
"for their decisive contributions to the large project, which led to the discovery of the field particles W and Z, communicators of weak interaction"[84]

Simon van der Meer
 Netherlands

1985

Klaus von Klitzing
 West Germany
"for the discovery of the quantized Hall effect"[85]

1986

Ernst Ruska
 West Germany
"for his fundamental work in electron optics, and for the design of the first electron microscope"[86]

Gerd Binnig
 West Germany
"for their design of the scanning tunneling microscope"[86]

Heinrich Rohrer
  Switzerland

1987

Johannes Georg Bednorz
 West Germany
"for their important break-through in the discovery of superconductivity in ceramic materials"[87]

Karl Alexander Müller
  Switzerland

1988

Leon Max Lederman
 United States
"for the neutrino beam method and the demonstration of the doublet structure of the leptons through the discovery of the muon neutrino"[88]

Melvin Schwartz
 United States

Jack Steinberger
 United States

1989

Norman Foster Ramsey
 United States
"for the invention of the separated oscillatory fields method and its use in the hydrogen maser and other atomic clocks"[89]

Hans Georg Dehmelt
 United States
 Germany
"for the development of the ion trap technique"[89]

Wolfgang Paul
 West Germany

1990

Jerome I. Friedman
 United States
"for their pioneering investigations concerning deep inelastic scattering of electrons on protons and bound neutrons, which have been of essential importance for the development of the quark model in particle physics"[90]

Henry Way Kendall
 United States

Richard E. Taylor
 Canada

1991

Pierre-Gilles de Gennes
 France
"for discovering that methods developed for studying order phenomena in simple systems can be generalized to more complex forms of matter, in particular to liquid crystals and polymers"[91]

1992

Georges Charpak
 France
 Poland
"for his invention and development of particle detectors, in particular the multiwire proportional chamber"[92]

1993

Russell Alan Hulse
 United States
"for the discovery of a new type of pulsar, a discovery that has opened up new possibilities for the study of gravitation"[93]

Joseph Hooton Taylor, Jr.
 United States

1994

Bertram Brockhouse
 Canada
"for the development of neutron spectroscopy" and "for pioneering contributions to the development of neutron scattering techniques for studies of condensed matter"[94]

Clifford Glenwood Shull
 United States
"for the development of the neutron diffraction technique" and "for pioneering contributions to the development of neutron scattering techniques for studies of condensed matter"[94]

1995

Martin Lewis Perl
 United States
"for the discovery of the tau lepton" and "for pioneering experimental contributions to lepton physics"[95]

Frederick Reines
 United States
"for the detection of the neutrino" and "for pioneering experimental contributions to lepton physics"[95]

1996

David Morris Lee
 United States
"for their discovery of superfluidity in helium-3"[96]

Douglas D. Osheroff
 United States

Robert Coleman Richardson
 United States

1997

Steven Chu
 United States
"for development of methods to cool and trap atoms with laser light."[97]

Claude Cohen-Tannoudji
 France

William Daniel Phillips
 United States

1998

Robert B. Laughlin
 United States
"for their discovery of a new form of quantum fluid with fractionally charged excitations"[98]

Horst Ludwig Störmer
 Germany

Daniel Chee Tsui
 Republic of China
 United States

1999

Gerard 't Hooft
 Netherlands
"for elucidating the quantum structure of electroweak interactions in physics"[99]

Martinus J. G. Veltman
 Netherlands

2000

Zhores Ivanovich Alferov
 Russia
"for developing semiconductor heterostructures used in high-speed- and optoelectronics"[100]

Herbert Kroemer
 Germany

Jack St. Clair Kilby
 United States
"for his part in the invention of the integrated circuit"[100]

2001

Eric Allin Cornell
 United States
"for the achievement of Bose–Einstein condensation in dilute gases of alkali atoms, and for early fundamental studies of the properties of the condensates"[101]

Carl Edwin Wieman
 United States

Wolfgang Ketterle
 Germany

2002

Raymond Davis, Jr.
 United States
"for pioneering contributions to astrophysics, in particular for the detection of cosmic neutrinos"[102]

Masatoshi Koshiba
 Japan

Riccardo Giacconi
 Italy
 United States
"for pioneering contributions to astrophysics, which have led to the discovery of cosmic X-ray sources"[102]

2003

Alexei Alexeyevich Abrikosov
 Russia
 United States
"for pioneering contributions to the theory of superconductors and superfluids"[103]

Vitaly Lazarevich Ginzburg
 Russia

Anthony James Leggett
 United Kingdom
 United States

2004

David J. Gross
 United States
"for the discovery of asymptotic freedom in the theory of the strong interaction"[104]

Hugh David Politzer
 United States

Frank Wilczek
 United States

2005

Roy J. Glauber
 United States
"for his contribution to the quantum theory of optical coherence"[105]

John L. Hall
 United States
"for their contributions to the development of laser-based precision spectroscopy, including the optical frequency comb technique"[105]

Theodor W. Hänsch
 Germany

2006

John C. Mather
 United States
"for their discovery of the blackbody form and anisotropy of the cosmic microwave background radiation"[106]

George F. Smoot
 United States

2007

Albert Fert
 France
"for the discovery of giant magnetoresistance"[107]

Peter Grünberg
 Germany

2008

Makoto Kobayashi
 Japan
"for the discovery of the origin of the broken symmetry which predicts the existence of at least three families of quarks in nature"[108]

Toshihide Maskawa
 Japan

Yoichiro Nambu
 Japan
 United States
"for the discovery of the mechanism of spontaneous broken symmetry in subatomic physics"[108]

2009

Charles K. Kao
 Hong Kong
 United Kingdom
 United States
"for groundbreaking achievements concerning the transmission of light in fibers for optical communication"[109]

Willard S. Boyle
 Canada
 United States
"for the invention of an imaging semiconductor circuit – the CCD sensor"[109]

George E. Smith
 United States

2010

Andre Geim
 Russia
 United Kingdom
 Netherlands
"for groundbreaking experiments regarding the two-dimensional material graphene"[110]

Konstantin Novoselov
 Russia
 United Kingdom

2011

Saul Perlmutter
 United States
"for the discovery of the accelerating expansion of the Universe through observations of distant supernovae"[111]

Brian P. Schmidt
 Australia
 United States

Adam G. Riess
 United States

2012

Serge Haroche
 France
"for ground-breaking experimental methods that enable measuring and manipulation of individual quantum systems."[112]

David J. Wineland
 United States

2013

François Englert
 Belgium
"for the theoretical discovery of a mechanism that contributes to our understanding of the origin of mass of subatomic particles, and which recently was confirmed through the discovery of the predicted fundamental particle, by the ATLAS and CMS experiments at CERN's Large Hadron Collider"[113]

Peter Higgs
 United Kingdom

2014

Isamu Akasaki
 Japan
"for the invention of efficient blue light-emitting diodes which has enabled bright and energy-saving white light sources"[114]

Hiroshi Amano
 Japan

Shuji Nakamura
 Japan
 United States

2015

Takaaki Kajita
 Japan
"for the discovery of neutrino oscillations, which shows that neutrinos have mass"[115]

Arthur B. McDonald
 Canada

2016

David J. Thouless
 United Kingdom
 United States
"for theoretical discoveries of topological phase transitions and topological phases of matter"[116]

F. Duncan M. Haldane
 United Kingdom
 United States

John M. Kosterlitz
 United Kingdom
 United States

2017

Rainer Weiss
 Germany
 United States
"for decisive contributions to the LIGO detector and the observation of gravitational waves"[117]

Kip Thorne
 United States

Barry Barish
 United States

tag: table


document_title: Shortwave radio

question_text: which mode is used for short wave broadcast service

text: Shortwave radio

text: Frequency classifications[edit]

text: The widest popular definition of the shortwave frequency interval is the ITU Region 1 (EU+Africa+Russia...) definition, and is the span 1.6–30 MHz, just above the medium wave band, which ends approximately at 1.6 MHz.

text: There are also other definitions of the shortwave frequency interval:

text:
1.71 to 30 MHz in ITU Region 2 (North and South America...)
1.8 (160 meter radio amateur band start) to 30 MHz
2.3 (120 meter band start) to 30 MHz
2.3 (120 meter band start) to 26.1 MHz (11 meter band end)[2][3]
In Germany and perhaps Austria the ITU Region 1 shortwave radio frequency interval can be subdivided in:

de:Grenzwelle ("border waves"): 1.605–3.8 MHz[4]

In Germany these shortwave radio frequency intervals have also been seen used:

the above other definitions[5]

tag: ul

text: History[edit]

text: Development[edit]

text: The name "shortwave" originated during the early days of radio in the early 20th century, when the radio spectrum was considered divided into long wave (LW), medium wave (MW) and short wave bands based on the wavelength of the radio waves. Shortwave radio received its name because the wavelengths in this band are relatively shorter than 200 m (1,500 kHz) which marked the original upper limit of the medium frequency band first used for radio communications. The broadcast medium wave band now extends above the 200 m/1,500 kHz limit, and the amateur radio 1.8 MHz – 2.0 MHz band (known as the "top band") is the lowest-frequency band considered to be 'shortwave'.

text: Early long distance radio telegraphy used long waves, below 300 kilohertz (kHz). The drawbacks to this system included a very limited spectrum available for long distance communication, and the very expensive transmitters, receivers and gigantic antennas that were required. It was also difficult to beam the radio wave directionally with long wave, resulting in a major loss of power over long distances. Prior to the 1920s, the shortwave frequencies above 1.5 MHz were regarded as useless for long distance communication and were designated in many countries for amateur use.[6]

text: Guglielmo Marconi, pioneer of radio, commissioned his assistant Charles Samuel Franklin to carry out a large scale study into the transmission characteristics of short wavelength waves and to determine their suitability for long distance transmissions. Franklin rigged up a large antenna at Poldhu Wireless Station, Cornwall, running on 25 kW of power. In June and July 1923, wireless transmissions were completed during nights on 97 meters from Poldhu to Marconi's yacht Elettra in the Cape Verde Islands.[7]

text: In September 1924, Marconi transmitted daytime and nighttime on 32 meters from Poldhu to his yacht in Beirut. Franklin went on to refine the directional transmission, by inventing the curtain array aerial system.[8][9] In July 1924, Marconi entered into contracts with the British General Post Office (GPO) to install high speed shortwave telegraphy circuits from London to Australia, India, South Africa and Canada as the main element of the Imperial Wireless Chain. The UK-to-Canada shortwave "Beam Wireless Service" went into commercial operation on 25 October 1926. Beam Wireless Services from the UK to Australia, South Africa and India went into service in 1927.[7]

text: Shortwave communications began to grow rapidly in the 1920s,[10] similar to the internet in the late 20th century. By 1928, more than half of long distance communications had moved from transoceanic cables and longwave wireless services to shortwave and the overall volume of transoceanic shortwave communications had vastly increased. Shortwave stations had cost and efficiency advantages over massive longwave wireless installations,[11] however some commercial longwave communications stations remained in use until the 1960s. Long distance radio circuits also reduced the load on the existing transoceanic telegraph cables and hence the need for new cables, although the cables maintained their advantages of high security and a much more reliable and better quality signal than shortwave.

text: The cable companies began to lose large sums of money in 1927, and a serious financial crisis threatened the viability of cable companies that were vital to strategic British interests. The British government convened the Imperial Wireless and Cable Conference[12] in 1928 "to examine the situation that had arisen as a result of the competition of Beam Wireless with the Cable Services". It recommended and received Government approval for all overseas cable and wireless resources of the Empire to be merged into one system controlled by a newly formed company in 1929, Imperial and International Communications Ltd. The name of the company was changed to Cable and Wireless Ltd. in 1934.

text: Long-distance cables had a resurgence beginning in 1956 with the laying of TAT-1 across the Atlantic Ocean, the first voice frequency cable on this route. This provided 36 high quality telephone channels and was soon followed by even higher capacity cables all around the world. These sounded the death knell of shortwave radio for commercial communications.

text: Amateur use of shortwave propagation[edit]

text: Amateur radio operators also discovered that long-distance communication was possible on shortwave bands. Early long-distance services used surface wave propagation at very low frequencies,[13] which are attenuated along the path at wavelengths shorter than 1,000 meters. Longer distances and higher frequencies using this method meant more signal loss. This, and the difficulties of generating and detecting higher frequencies, made discovery of shortwave propagation difficult for commercial services.

text: Radio amateurs may have conducted the first successful transatlantic tests in December 1921,[14] operating in the 200 meter mediumwave band (near 1,500 kHz in the modern AM broadcast band) – the shortest wavelength then available to amateurs. In 1922 hundreds of North American amateurs were heard in Europe on 200 meters and at least 20 North American amateurs heard amateur signals from Europe. The first two-way communications between North American and Hawaiian amateurs began in 1922 at 200 meters. Although operation on wavelengths shorter than 200 meters was technically illegal (but tolerated as the authorities mistakenly believed at first that such frequencies were useless for commercial or military use), amateurs began to experiment with those wavelengths using newly available vacuum tubes shortly after World War I.

text: Extreme interference at the longer edge of the 150–200 meter band – the official wavelengths allocated to amateurs by the Second National Radio Conference[15] in 1923 – forced amateurs to shift to shorter and shorter wavelengths; however, amateurs were limited by regulation to wavelengths longer than 150 meters (2 MHz). A few fortunate amateurs who obtained special permission for experimental communications at wavelengths shorter than 150 meters completed hundreds of long distance two way contacts on 100 meters (3 MHz) in 1923 including the first transatlantic two way contacts.[16]

text: By 1924 many additional specially licensed amateurs were routinely making transoceanic contacts at distances of 6,000 miles (9,600 km) and more. On 21 September 1924 several amateurs in California completed two-way contacts with an amateur in New Zealand. On 19 October amateurs in New Zealand and England completed a 90 minute two-way contact nearly halfway around the world. On 10 October the Third National Radio Conference made three shortwave bands available to U.S. amateurs[17] at 80 meters (3.75 MHz), 40 meters (7 MHz) and 20 meters (14 MHz). These were allocated worldwide, while the 10 meter band (28 MHz) was created by the Washington International Radiotelegraph Conference[18] on 25 November 1927. The 15 meter band (21 MHz) was opened to amateurs in the United States on 1 May 1952.

text: Propagation characteristics[edit]

text: Shortwave radio frequency energy is capable of reaching any location on the Earth as it is influenced by ionospheric reflection back to the earth by the ionosphere, (a phenomenon known as "skywave propagation"). A typical phenomenon of shortwave propagation is the occurrence of a skip zone where reception fails. With a fixed working frequency, large changes in ionospheric conditions may create skip zones at night.

text: As a result of the multi-layer structure of the ionosphere, propagation often simultaneously occurs on different paths, scattered by the E or F region and with different numbers of hops, a phenomenon that may be disturbed for certain techniques. Particularly for lower frequencies of the shortwave band, absorption of radio frequency energy in the lowest ionospheric layer, the D layer, may impose a serious limit. This is due to collisions of electrons with neutral molecules, absorbing some of a radio frequency's energy and converting it to heat.[19] Predictions of skywave propagation depend on:

text:
The distance from the transmitter to the target receiver.
Time of day. During the day, frequencies higher than approximately 12 MHz can travel longer distances than lower ones. At night, this property is reversed.
With lower frequencies the dependence on the time of the day is mainly due to the lowest ionospheric layer, the D Layer, forming only during the day when photons from the sun break up atoms into ions and free electrons.
Season. During the winter months of the Northern or Southern hemispheres, the AM/MW broadcast band tends to be more favorable because of longer hours of darkness.
Solar flares produce a large increase in D region ionization so high, sometimes for periods of several minutes, all skywave propagation is nonexistent.

text: Types of modulation[edit]

text: Several different types of modulation are used to impress information on a short-wave transmission.

text: Amplitude modulation is the simplest type and the most commonly used for shortwave broadcasting. The instantaneous amplitude of the carrier is controlled by the amplitude of the signal (speech, or music, for example). At the receiver, a simple detector recovers the desired modulation signal from the carrier.

text: Single sideband transmission is a form of amplitude modulation but in effect filters the result of modulation. An amplitude-modulated signal has frequency components both above and below the carrier frequency. If one set of these components is eliminated as well as the residual carrier, only the remaining set is transmitted. This reduces power in the transmission, as roughly 2/3 of the energy sent by an AM signal is unnecessary to recover the information contained on it. It also reduces "bandwidth", enabling about one-half the carrier frequency spectrum width to be used. The drawback is the receiver is more complicated, since it must re-create the carrier to recover the signal. Small errors in the detection process greatly affect the pitch of the received signal. As a result, single sideband is not used for music or general broadcast. Single sideband is used for long-range voice communications by ships and aircraft, Citizen's Band, and amateur radio operators. Lower sideband (LSB) is generally used below 9 MHz and USB (upper sideband) above 9 MHz.

text: Vestigal sideband transmits the carrier and one complete sideband, but filters out the other sideband. It is a compromise between AM and SSB, enabing simple receivers to be used, but requires almost as much transmitter power as AM. One advantage is only half the bandwidth of an AM signal is used. It can be heard in the transmission of certain radio time signal stations. Vestigial sideband is used for over the air Television Broadcasts both analog and digital.

text: Continuous wave (CW) is on-and-off keying of a carrier, used for Morse code communications and Hellschreiber facsimile-based teleprinter transmissions.[21]

text: Narrow-band frequency modulation (NBFM) is used typically above 20 MHz. Because of the larger bandwidth required, NBFM is commonly used for VHF communication. Regulations limit the bandwidth of a signal transmitted in the HF bands, and the advantages of frequency modulation are greatest if the FM signal has a wide bandwidth. NBFM is limited to short-range transmissions due to the multiphasic distortions created by the ionosphere.[22]

text: Digital Radio Mondiale (DRM) is a digital modulation for use on bands below 30 MHz.

text: Radioteletype, fax, digital, slow-scan television and other systems use forms of frequency-shift keying or audio subcarriers on a shortwave carrier. These generally require special equipment to decode, such as software on a computer equipped with a sound card.

text: Users[edit]

text: Some established users of the shortwave radio bands may include:

text:
International broadcasting primarily by government-sponsored propaganda, international news (for example, the BBC World Service) or cultural stations to foreign audiences: the most common use of all.
Domestic broadcasting: to widely dispersed populations with few longwave, mediumwave and FM stations serving them; or for specialty political, religious and alternative media networks; or of individual commercial and non-commercial paid broadcasts.
Oceanic air traffic control uses the HF/shortwave band for long distance communication to aircraft over the oceans and poles, which are far beyond the range of traditional VHF frequencies. Modern systems also include satellite communications, such as ADS-C/CPDLC
"Utility" stations transmitting messages not intended for the general public, such as merchant shipping, marine weather, and ship-to-shore stations; for aviation weather and air-to-ground communications; for military communications; for long-distance governmental purposes, and for other non-broadcast communications.
Amateur radio operators at the 80/75, 60, 40, 30, 20, 17, 15, 12, and 10-meter bands. Licenses are granted by authorized government agencies.
Time signal and radio clock stations: In North America, WWV radio and WWVH radio transmit at these frequencies: 2.5 MHz, 5 MHz, 10 MHz, and 15 MHz; and WWV also transmits on 20 MHz. The CHU radio station in Canada transmits on the following frequencies: 3.33 MHz, 7.85 MHz, and 14.67 MHz. Other similar radio clock stations transmit on various shortwave and longwave frequencies around the world. The shortwave transmissions are primarily intended for human reception, while the longwave stations are generally used for automatic synchronization of watches and clocks.

text: Sporadic or non-traditional users of the shortwave bands may include:

text:
Clandestine stations. These are stations that broadcast on behalf of various political movements such as rebel or insurrectionist forces. They may advocate civil war, insurrection, rebellion against the government-in-charge of the country to which they are directed. Clandestine broadcasts may emanate from transmitters located in rebel-controlled territory or from outside the country entirely, using another country's transmission facilities.[23]
Numbers Stations. These stations regularly appear and disappear all over the shortwave radio band but are unlicensed and untraceable. It is believed that Numbers Stations are operated by government agencies and are used to communicate with clandestine operatives working within foreign countries. However, no definitive proof of such use has emerged. Because the vast majority of these broadcasts contain nothing but the recitation of blocks of numbers, in various languages, with occasional bursts of music, they have become known colloquially as "Number Stations". Perhaps the most noted Number Station is the "Lincolnshire Poacher", named after the 18th century English folk song, which is transmitted just before the sequences of numbers.
Unlicensed two way radio activity by individuals such as taxi drivers, bus drivers and fishermen in various countries can be heard on various shortwave frequencies. Such unlicensed transmissions by "pirate" or "bootleg" two way radio operators[24] can often cause signal interference to licensed stations.[25]
Pirate radio broadcasters who feature programming such as music, talk and other entertainment, can be heard sporadically and in various modes on the shortwave bands.[26]
Over-the-horizon radar: From 1976 to 1989, the Soviet Union's Russian Woodpecker over-the-horizon radar system blotted out numerous shortwave broadcasts daily.
Ionospheric heaters used for scientific experimentation such as the High Frequency Active Auroral Research Program in Alaska, and the Sura ionospheric heating facility in Russia.[27]

text: Shortwave broadcasting[edit]

text: See International broadcasting for details on the history and practice of broadcasting to foreign audiences.

text: See Shortwave relay station for the actual kinds of integrated technologies used to bring high power signals to listeners.

text: Frequency allocations[edit]

text: The World Radiocommunication Conference (WRC), organized under the auspices of the International Telecommunication Union, allocates bands for various services in conferences every few years. The last WRC took place in 2007.

text: At WRC-97 in 1997, the following bands were allocated for international broadcasting. AM shortwave broadcasting channels are allocated with a 5 kHz separation for traditional analog audio broadcasting.

text:
Metre Band
Frequency Range
Remarks

120 m
2.3–2.495 MHz
tropical band

90 m
3.2–3.4 MHz
tropical band

75 m
3.9–4 MHz
shared with the North American amateur radio 80m band

60 m
4.75–5.06 MHz
tropical band

49 m
5.9–6.2 MHz

41 m
7.2–7.6 MHz
shared with the amateur radio 40m band

31 m
9.4–9.9 MHz
currently the most heavily used band

25 m
11.6–12.2 MHz

22 m
13.57–13.87 MHz

19 m
15.1–15.8 MHz

16 m
17.48–17.9 MHz

15 m
18.9–19.02 MHz
almost unused, could become a DRM band

13 m
21.45–21.85 MHz

11 m
25.6–26.1 MHz
may be used for local DRM broadcasting

text: Although countries generally follow the table above, there may be small differences between countries or regions. For example, in the official bandplan of the Netherlands,[28] the 49 m band starts at 5.95 MHz, the 41 m band ends at 7.45 MHz, the 11 m band starts at 25.67 MHz, and the 120, 90 and 60 m bands are absent altogether. Additionally, international broadcasters sometimes operate outside the normal WRC-allocated bands or use off-channel frequencies. This is done for practical reasons, or to attract attention in crowded bands (60m, 49m, 40m, 41m, 31m, 25m).

text: The new digital audio broadcasting format for shortwave DRM operates 10 kHz or 20 kHz channels. There are some ongoing discussions with respect to specific band allocation for DRM, as it mainly transmitted in 10 kHz format.

text: The power used by shortwave transmitters ranges from less than one watt for some experimental and amateur radio transmissions to 500 kilowatts and higher for intercontinental broadcasters and over-the-horizon radar. Shortwave transmitting centers often use specialized antenna designs (like the ALLISS antenna technology) to concentrate radio energy at the target area.

text: Advantages[edit]

text: Shortwave does possess a number of advantages over newer technologies, including the following:

text:
Difficulty of censoring programming by authorities in restrictive countries: unlike their relative ease in monitoring the Internet, government authorities face technical difficulties monitoring which stations (sites) are being listened to (accessed). For example, during the attempted coup against Soviet President Mikhail Gorbachev, when his access to communications was limited (e.g. his phones were cut off, etc.), Gorbachev was able to stay informed by means of the BBC World Service on shortwave.[29]
Low-cost shortwave radios are widely available in all but the most repressive countries in the world. Simple shortwave regenerative receivers can be easily built with a few parts.
In many countries (particularly in most developing nations and in the Eastern bloc during the Cold War era) ownership of shortwave receivers has been and continues to be widespread[30] (in many of these countries some domestic stations also used shortwave).
Many newer shortwave receivers are portable and can be battery-operated, making them useful in difficult circumstances. Newer technology includes hand-cranked radios which provide power without batteries.
Shortwave radios can be used in situations where Internet or satellite communications service is temporarily or long-term unavailable (or unaffordable).
Shortwave radio travels much farther than broadcast FM (88–108 MHz). Shortwave broadcasts can be easily transmitted over a distance of several thousands of kilometers, including from one continent to another.
Particularly in tropical regions, SW is somewhat less prone to interference from thunderstorms than medium wave radio, and is able to cover a large geographic area with relatively low power (and hence cost). Therefore, in many of these countries it is widely used for domestic broadcasting.
Very little infrastructure is required for long-distance two-way communications using shortwave radio. All one needs is a pair of transceivers, each with an antenna, and a source of energy (such as a battery, a portable generator, or the electrical grid). This makes shortwave radio one of the most robust means of communications, which can be disrupted only by interference or bad ionospheric conditions. Modern digital transmission modes such as MFSK and Olivia are even more robust, allowing successful reception of signals well below the noise floor of a conventional receiver.

text: Disadvantages[edit]

text: Shortwave radio's benefits are sometimes regarded as being outweighed by its drawbacks, including:

text:
In most Western countries, shortwave radio ownership is usually limited to true enthusiasts, since most new standard radios do not receive the shortwave band. Therefore, Western audiences are limited.
In the developed world, shortwave reception is very difficult in urban areas because of excessive noise from switched-mode power adapters, fluorescent or LED light sources, internet modems and routers, computers and many other sources of radio interference.

text: Shortwave listening[edit]

text: The Asia-Pacific Telecommunity estimates that there are approximately 600 million shortwave broadcast-radio receivers in use in 2002.[31] WWCR claims that there are 1.5 billion shortwave receivers worldwide.[32]

text: Many hobbyists listen to shortwave broadcasters. In some cases, the goal is to hear as many stations from as many countries as possible (DXing); others listen to specialized shortwave utility, or "ute", transmissions such as maritime, naval, aviation, or military signals. Others focus on intelligence signals from numbers stations, stations which transmit strange broadcast usually for intelligence operations, or the two way communications by amateur radio operators. Some short wave listeners behave analogously to "lurkers" on the Internet, in that they listen only and never make any attempt to send out their own signals. Other listeners participate in clubs, or actively send and receive QSL cards, or become involved with amateur radio and start transmitting on their own.

text: Many listeners tune the shortwave bands for the programmes of stations broadcasting to a general audience (such as Radio Taiwan International, China Radio International, Voice of America, Radio France Internationale, BBC World Service, Voice of Korea, Radio Free Sarawak etc.). Today, through the evolution of the Internet, the hobbyist can listen to shortwave signals via remotely controlled or web controlled shortwave receivers around the world, even without owning a shortwave radio.[33] Many international broadcasters offer live streaming audio on their websites and a number have closed their shortwave service entirely, or severely curtailed it, in favour of internet transmission.

text: Shortwave listeners, or SWLs, can obtain QSL cards from broadcasters, utility stations or amateur radio operators as trophies of the hobby. Some stations even give out special certificates, pennants, stickers and other tokens and promotional materials to shortwave listeners.

text: Shortwave broadcasts and music[edit]

text: Some musicians have been attracted to the unique aural characteristics of shortwave radio which—due to the nature of amplitude modulation, varying propagation conditions, and the presence of interference—generally has lower fidelity than local broadcasts (particularly via FM stations). Shortwave transmissions often have bursts of distortion, and "hollow" sounding loss of clarity at certain aural frequencies, altering the harmonics of natural sound and creating at times a strange "spacey" quality due to echoes and phase distortion. Evocations of shortwave reception distortions have been incorporated into rock and classical compositions, by means of delays or feedback loops, equalizers, or even playing shortwave radios as live instruments. Snippets of broadcasts have been mixed into electronic sound collages and live musical instruments, by means of analogue tape loops or digital samples. Sometimes the sounds of instruments and existing musical recordings are altered by remixing or equalizing, with various distortions added, to replicate the garbled effects of shortwave radio reception.[34][35][36]

text: The first attempts by serious composers to incorporate radio effects into music may be those of the Russian physicist and musician Léon Theremin,[36] who perfected a form of radio oscillator as a musical instrument in 1928 (regenerative circuits in radios of the time were prone to breaking into oscillation, adding various tonal harmonics to music and speech); and in the same year, the development of a French instrument called the Ondes Martenot by its inventor Maurice Martenot, a French cellist and former wireless telegrapher. Karlheinz Stockhausen used shortwave radio and effects in works including Hymnen (1966–67), Kurzwellen (1968)—adapted for the Beethoven Bicentennial in Opus 1970 with filtered and distorted snippets of Beethoven pieces—Spiral (1968), Pole, Expo (both 1969–70), and Michaelion (1997).[34]

text: Cypriot composer Yannis Kyriakides incorporated shortwave numbers station transmissions in his 1999 ConSPIracy cantata.[37]

text: Holger Czukay, a student of Stockhausen, was one of the first to use shortwave in a rock music context.[35] In 1975, German electronic music band Kraftwerk recorded a full length concept album around simulated radiowave and shortwave sounds, entitled Radio-Activity.[38] The The's Radio Cineola monthly broadcasts drew heavily on shortwave radio sound.[39]

text: Shortwave's future[edit]

text: The development of direct broadcasts from satellites has reduced the demand for shortwave receiver hardware, but there are still a great number of shortwave broadcasters. A new digital radio technology, Digital Radio Mondiale (DRM), is expected to improve the quality of shortwave audio from very poor to standards comparable to the FM broadcast band.[40] The future of shortwave radio is threatened by the rise of power line communication (PLC), also known as Broadband over Power Lines (BPL), which uses a data stream transmitted over unshielded power lines. As the BPL frequencies used overlap with shortwave bands, severe distortions can make listening to analog shortwave radio signals near power lines difficult or impossible.[41]

text: Experts disagree on the future of shortwave. According to Andy Sennitt, former editor of the World Radio TV Handbook, “shortwave is a legacy technology, which is expensive and environmentally unfriendly. A few countries are hanging on to it, but most have faced up to the fact that the glory days of shortwave have gone. Religious broadcasters will still use it because they are not too concerned with listening figures".[40]

text: However Thomas Witherspoon, editor of shortwave news site SWLingPost.com wrote that “shortwave remains the most accessible international communications medium that still provides listeners with the protection of complete anonymity". According to Nigel Fry, head of Distribution for the BBC World Service Group, “I still see a place for shortwave in the 21st century, especially for reaching areas of the world that are prone to natural disasters that destroy local broadcasting and Internet infrastructure".[40]


document_title: Geography of Nigeria

question_text: the south west wind blows across nigeria between

text: Geography of Nigeria

text: Climate types found in Nigeria[edit]

text: The tropical monsoon climate, designated by the Köppen climate classification as "Am", is found in the southern part of the country. This climate is influenced by the monsoons originating from the South Atlantic ocean, which is brought into the country by the (maritime tropical) MT airmass, a warm moist sea to land seasonal wind. Its warmth and high humidity gives it a strong tendency to ascend and produce copious rainfall, which is a result of the condensation of water vapour in the rapidly rising air.[1]

text: The Tropical monsoon climate has a very small temperature range. Then temperature ranges are almost constant throughout the year, for example, Warri town in the southern part of Nigeria, records a maximum of 28 °C (82.4 °F) for its hottest month while its lowest temperature is 26 °C (78.8 °F) in its coldest month. The temperature difference of Warri town is not more than 2 °C (5 °F).

text: The southern part of Nigeria experiences heavy and abundant rainfall. These storms are usually convectional in nature due to the regions proximity, to the equatorial belt. The annual rainfall received in this region is very high, usually above the 2,000 mm (78.7 in) rainfall totals giving for tropical rainforest climates worldwide. Over 4,000 mm (157.5 in) of rainfall is received in the coastal region of Nigeria around the Niger delta area. Bonny town found in the coastal region of the Niger delta area in southern Nigeria receives well over 4,000 mm (157.5 in) of rainfall annually. The rest of the southeast receives between 2,000 and 3,000 mm (118.1 in) of rain per year.

text: The southern region of Nigeria experiences a double rainfall maxima characterised by two high rainfall peaks, with a short dry season and a longer dry season falling between and after each peaks. The first rainy season begins around March and last to the end of July with a peak in June, this rainy season is followed by a short dry break in August known as the August break which is a short dry season lasting for two to three weeks in August. This break is broken by the short rainy season starting around early September and lasting to Mid October with a peak period at the end of September. The ending of the short rainy season in October is followed by long dry season. This period starts from late October and lasts till early March with peak dry conditions between early December and late February.[2]

text: The tropical savanna climate or tropical wet and dry climate, is extensive in area and covers most of Western Nigeria to central Nigeria beginning from the Tropical rainforest climate boundary in southern Nigeria to the central part of Nigeria, where it exerts enormous influence on the region.

text: This climate, the tropical savanna climate exhibits a well marked rainy season and a dry season with a single peak known as the summer maximum due to its distance from the equator. Temperatures are above 18 °C (64 °F) throughout the year. Abuja, Nigeria's capital city found in central Nigeria, has a temperature range of 18.45 °C (65.21 °F) to 36.9 °C (98.4 °F), and an annual rainfall of about 1,500 mm (59.1 in) with a single rainfall maxima in September.[3]

text: The single Dry season experienced in this climate, the tropical savanna climate in central Nigeria beginning from December to march, is hot and dry with the Harmattan wind, a continental tropical (CT) airmass laden with dust from the Sahara Desert prevailing throughout this period.

text: With the Intertropical Convergence Zone (ITCZ) swinging northward over West Africa from the Southern Hemisphere in April, heavy showers coming from pre-monsoonal convective clouds mainly in the form of squall lines also known as the north easterlies formed mainly as a result of the interactions of the two dominant airmasses in Nigeria known as the Maritime tropical(south westerlies) and the Continental tropical(north easterlies),[4] begins in central Nigeria while the Monsoons from the south atlantic ocean arrives in central Nigeria in July bringing with it high humidity, heavy cloud cover and heavy rainfall which can be daily occurrence lasting till September when the monsoons gradually begin retreating southward to the southern part of Nigeria.Rainfall totals in central Nigeria varies from 1,100 mm (43.3 in) in the lowlands of the river Niger Benue trough to over 2,000 mm (78.7 in) along the south western escarpment of the Jos Plateau.[5]

text:
The Sahel climate or tropical dry climate, is the predominant climate type in the northern part of Nigeria. Annual rainfall totals are lower compared to the southern and central part of Nigeria.
The rainy season in the northern part of Nigeria last for only three to four months (June–September). The rest of the year is hot and dry with temperatures climbing as high as 40 °C (104.0 °F) .

text: Alpine climate or highland climate or mountain climate are found on highlands regions in Nigeria. Highlands with the alpine climate in Nigeria, are well over 1,520 metres (4,987 ft) above sea level. Due to their location in the tropics, this elevation is high enough to reach the temperate climate line in the tropics thereby giving the highlands, mountains and the plateau regions standing above this height, a cool mountain climate.

text: Seasons[edit]

text: Nigeria, like the rest of West Africa and other tropical lands, has only two seasons. These are the dry season and the rainy season. The dry season is accompanied by a dust laden airmass from the Sahara Desert, locally known as Harmattan, or by its main name, The Tropical Continental (CT) airmass, while the rainy season is heavily influenced by an airmass originating from the south atlantic ocean, locally known as the south west wind, or by its main name, The Tropical Maritime (MT) airmass. These two major wind systems in Nigeria are known as the trade winds.

text: Trade winds[edit]

text: Tropical maritime airmass[edit]

text: The tropical maritime airmass (MT) is responsible for Nigeria's rainy season. This wind (the tropical maritime airmass) invades the country from February in the southern part of Nigeria while it takes longer for the wind to fully cover the whole of the country, reaching the northern part of Nigeria in June. Its invasion is as a result of the northward retreat, of the tropical continental airmass (CT) known as the harmattan. The northward retreat of the tropical continental airmass (CT), is caused by the sun's northward shift from the tropic of capricorn in the southern hemisphere to the tropic of cancer in the northern hemisphere. This shift begins from February and ends in June, when the sun is fully overhead, at the tropic of cancer in the northern hemisphere.

text: During this northward migration of the sun as a result of the earth tilting along its axis, the sun crosses the equator (around March), moving over west Africa at this time on its journey to the northern hemisphere. West Africa comes directly under the sun at this time. The sun is overhead throughout west Africa and over Nigeria during this period of the sun's northward migration to the tropic of cancer in the northern hemisphere.

text: The whole of West Africa is heated intensely as result of the increased insolation received from the sun being overhead over west Africa. Temperatures can climb as high as 35 °C (95.0 °F) over west Africa during this time. Temperatures in the northern part of Nigeria can go as high as 48 °C (118.4 °F) in cities like Maiduguri.[6]

text: The high temperatures coupled with an increase in insolation causes a region of low pressure to develop over west Africa and Nigeria (between March to May). The Tropical continental airmass (CT) from the Sahara Desert in the northern part of West Africa, is weakened due to the overheating of the land surface in west Africa and Nigeria at this time. The Tropical continental airmass (CT) begins to retreat northwards to the Sahara Desert due to massive heating of the land which transfers heat in the form of convection into the Tropical continental airmass (CT) which constitutes the main layer of air above the land. This transfer of heat in the Tropical continental airmass (CT) in turn, causes the wind to expand and become lighter as this is the normal behaviour for winds moving above intensely heated grounds. The Tropical continental airmass (CT) loses its strength as a major airmass in the region of west Africa and over Nigeria at this time (around February in the southern part of Nigeria to June in northern Nigeria) and begins to retreat coupled with the rising of air in form of convection within this airmass (Tropical continental airmass (CT)), further weakening the dominance of the wind over west Africa and Nigeria. The Tropical continental airmass (CT) finally retreats from most part of Nigeria, and the West African atmosphere around April to May, leaving an empty atmosphere over Nigeria. The sun's rays enters into the atmosphere of Nigeria more intense than it does during the presence of the Tropical continental airmass, which contained dust (in form of haze) that reduced the intensity of the sun.[7] The overheating of the west Africa land mass and Nigeria in particular creates a low pressure region over west Africa and Nigeria. This low pressure zone attracts the Tropical Maritime Airmass (MT) from the south Atlantic Ocean since areas of low pressures experiences inward blowing winds because winds are moving air blowing outwards from regions of high pressure to regions of low pressure.

text: The Tropical Maritime Airmass is a warm humid and unstable trade wind due to its warmth. Convectional currents are easily set up within the airmass whenever there is little instability in the airmass as a result of a slight to a very high orographic uplift in mountainous regions like the obudu plateau or the heating of the land which can trigger the formation of cumulonimbus cloud leading to thunderstorms within the airmass.

text: During the dominance of the Tropical Maritime Airmass (MT) in the rainy season of Nigeria, mornings are bright and sunny, the sun's heating of the land in the mornings and afternoons sets up convectional currents, these currents rise vertically and cumulonimbus clouds are formed, by afternoons to evenings, torrential downpour follows.

text: The Easterly wave or the African easterly waves is another major contributor of rainfall during the summer monsoons months of May to September in Nigeria.

text: The nature of this waves changes at about the 15 degrees line. The waves that pass south of this line carry moisture and create convection that leads to rain clouds.[8] Nigeria's northern end is south of the 15 degrees line at about 14 degrees.[9] Nigeria's location in the wetter part of the easterly waves south of the 15 degree line creates wetter climatic conditions for Nigeria especially during the monsoons.

text: Tropical continental airmass[edit]

text: The Tropical Continental Airmass (CT) locally known as the harmattan, is a wind originating from North Africa which crosses the Sahara Desert into west Africa to Nigeria. This airmass dominates Nigeria's climate during the dry season from December to March. The Tropical continental airmass is dusty and creates a haze within the atmosphere of west Africa and Nigeria when it predominates. The haze is as a result of the dust within the airmass limiting visibility and blocking much of the sun's rays from reaching the earth.

text: Effects of the tropical continental airmass[edit]

text: The mass has no ability of forming rain due to low humidity within the airmass, since it crosses the Sahara Desert, it picks up dust instead of water thereby creating little chances for rainfall.

text: The airmass makes life difficult as a result of low visibility which hampers transportation. The dust haze creates an almost desert conditions in the country during the dominance of the Tropical continental airmass (the harmattan). But its coming brings some relief to farmers since the low humidity present in the air quickens the drying of their crops.

text: Temperature[edit]

text: Nigeria's location in the tropics has given her a tropical hot climate. Temperatures in Nigeria vary according to the seasons of the year as with other lands found in the tropics. Nigeria's seasons are determined by rainfall with rainy season and dry season being the major seasons in Nigeria.

text: The rainy season of Nigeria brings in cooler weather to the country as a result of an increased cloud cover that acts as a blockage to the intense sunshine of the tropics by blocking much of the suns rays in the rainy season; this in turn cools the land, and the winds above the ground remains cool thereby making for cooler temperatures during the rainy season. But afternoons in the rainy season can be hot and humid, a feature of tropical climates. In the rainy season it is damp, and the rainfalls are usually abundant.

text: The dry season of Nigeria is a period of little cloud cover in the southern part of Nigeria to virtually no cloud cover in the northern part of Nigeria. The sun shines through the atmosphere with little obstructions from the clear skies making the dry season in Nigeria a period of warm weather conditions.In the middle of the dry season around December, a dusty wind from the Sahara Desert called the harmattan enters Nigeria from the northeastern part of the country blocking sun rays partially from shining and also creating haze in the atmosphere, this activities of the wind lowers temperatures considerably saving inhabitants for sometime, from the scorching heat that would have occurred as a result of clearer skies during the dry season. But with the withdrawal of this wind around March to April following the onset of the rainy season, temperatures can go as high as 44 °C (111.2 °F) in some parts of Nigeria.[10]

text: Semi temperate weather conditions prevail on the highlands in central Nigeria above 1,200 metres (3,937 ft) above sea level, namely the Jos Plateau. Temperatures on the Jos plateau ranges between 21 °C to 25 °C which are cool all year round.

text: Temperate weather conditions occur on the highlands along the Nigeria Cameroon border, in the eastern part of Nigeria. Highlands in these region attain an average height of more than 1,524 m (5,000 ft) to some standing above 2,000 metres (6,562 ft) above sea level. The climate on these highlands is temperate all year round. The major highlands in this region are the Obudu Plateau above 1,584 m (5,197 ft), Mambilla Plateau above 1,524 m (5,000 ft) and Mt Chappal Waddi above 2,000 m (6,562 ft).

text: Topography[edit]

text: Nigeria's most expansive topographical region is that of the valleys of the Niger and Benue River valleys (which merge into each other and form a "y" shaped confluence at Lokoja).[11] Plains rise to the north of the valleys. To the southwest of the Niger there is "rugged" highland, and to the southeast of the Benue hills and mountains are found all the way to the border with Cameroon. Coastal plains are found in both the southwest and the southeast.[11]

text: Niger Delta[edit]

text: This section needs expansion. You can help by adding to it. (January 2011)

text: The Niger Delta is located in the southern part of Nigeria. It is one of the world's largest arcuate fan-shaped river deltas.

text: The riverine area of the Niger Delta is a coastal belt of swamps bordering the Atlantic ocean. The swamps are vegetated tidal flats formed by a reticulate pattern of interconnected meandering creeks and distributaries of the River Niger.

text: Vegetation of the Niger Delta[edit]

text: The vegetation of the Niger Delta consist mainly of forest swamps. The forest are of two types, nearest the sea is a belt of saline/brackish Mangrove swamp separated from the sea by sand beach ridges within the mangrove swamp. Numerous sandy islands occur with fresh water vegetation. Fresh water swamps gradually supersede the mangrove on the landward side. About 70% of Nigeria's crude oil and gas production is from the area.

text: Human population in the Niger Delta[edit]

text: The riverine area is home to a large population of people living mainly in small villages scattered along the banks of rivers and creeks.

text: Rainfall in Niger Delta[edit]

text: Rainfall in the coastal belt of the Niger Delta is heavy due to the closeness of the Delta region to the equator. Annual rainfall totals vary from 2400 to over 4000 millimeters.

text: Niger Delta cities and their annually rainfall totals in millimeters:

text:
Warri — 2,730mm
Forcados (coastal town in the Niger Delta) — 4,870mm
Port Harcourt — 2,400mm
Calabar (coastal city) — 3,070mm (rainiest city with over one million people in Nigeria)
Bonny (south of Port Harcourt) — 4,200mm

text: Vegetation[edit]

text: Nigeria is covered by three types of vegetation: forests (where there is significant tree cover), savannahs (insignificant tree cover, with grasses and flowers located between trees), and montane land. (The latter is the least common, and is mainly found in the mountains near the Cameroon border.) Both the forest zone and the savannah zone are divided into three parts.[12]

text: Some of the forest zone's most southerly portion, especially around the Niger River and Cross River deltas, is mangrove swamp (see Central African mangroves). North of this is fresh water swamp, containing different vegetation from the salt water mangrove swamps, and north of that is rain forest.[12]

text: The savannah zone's three categories are divided into mm' Guinean forest-savanna mosaic, made up of plains of tall grass which are interrupted by trees, the most common across the country; Sudan savannah, similar but with shorter grasses and shorter trees; and Sahel savannah patches of grass and sand, found in the northeast.[12]

text: Natural resources and land use[edit]

text: Nigeria's natural resources include but are not limited to petroleum (see petroleum in Nigeria), tin, columbite, iron ore, coal, limestone, lead, zinc, natural gas, hydropower, and arable land.

text: Extreme points[edit]

text: This is a list of the extreme points of Nigeria, the points that are farther north, south, east or west than any other location.

text:
Northernmost point – unnamed location on the border with Niger immediately northwest of the town of Chadawa, Sokoto State.
Easternmost point – unnamed location on the border with Cameroon immediately east of the village of Munyego, Borno State.
Southernmost point – unnamed headland south of the town of Egeregere, Bayelsa State.
Westernmost point – unnamed location on the border with Benin Republic immediately east of the Beninoise town of Jabata, Oyo State.


document_title: Governor-General of India

question_text: who was the governor general of india when country became independent

text: Governor-General of India

text: History[edit]

text: Many parts of the Indian subcontinent were governed by the East India Company, which nominally acted as the agent of the Mughal Emperor. In 1773, motivated by corruption in the Company, the British government assumed partial control over the governance of India with the passage of the Regulating Act of 1773. A Governor-General and Supreme Council of Bengal were appointed to rule over the Presidency of Fort William in Bengal. The first Governor-General and Council were named in the Act.

text: The Charter Act 1833 replaced the Governor-General and Council of Fort William with the Governor-General and Council of India. The power to elect the Governor-General was retained by the Court of Directors, but the choice became subject to the Sovereign's approval.

text: After the Indian Rebellion of 1857, the East India Company's territories in India were put under the direct control of the Sovereign. The Government of India Act 1858 vested the power to appoint the Governor-General in the Sovereign. The Governor-General, in turn, had the power to appoint all lieutenant governors in India, subject to the Sovereign's approval.

text: India and Pakistan acquired independence in 1947, but Governors-General continued to be appointed over each nation until republican constitutions were written. Louis Mountbatten, 1st Earl Mountbatten of Burma remained Governor-General of India for some time after independence, but the two nations were otherwise headed by native Governors-General. India became a secular republic in 1950; Pakistan became an Islamic one in 1956.

text: Functions[edit]

text: The Governor-General originally had power only over the Presidency of Fort William in Bengal. The Regulating Act, however, granted them additional powers relating to foreign affairs and defence. The other Presidencies of the East India Company (Madras, Bombay and Bencoolen) were not allowed to declare war on or make peace with an Indian prince without receiving the prior approval of the Governor-General and Council of Fort William.[citation needed]

text: The powers of the Governor-General, in respect of foreign affairs, were increased by the India Act 1784. The Act provided that the other Governors under the East India Company could not declare war, make peace or conclude a treaty with an Indian prince unless expressly directed to do so by the Governor-General or by the Company's Court of Directors.

text: While the Governor-General thus became the controller of foreign policy in India, he was not the explicit head of British India. That status came only with the Charter Act 1833, which granted him "superintendence, direction and control of the whole civil and military Government" of all of British India. The Act also granted legislative powers to the Governor-General and Council.

text: After 1858, the Governor-General (now usually known as the Viceroy) functioned as the chief administrator of India and as the Sovereign's representative. India was divided into numerous provinces, each under the head of a Governor, Lieutenant Governor or Chief Commissioner or Administrator. Governors were appointed by the British Government, to whom they were directly responsible; Lieutenant Governors, Chief Commissioners, and Administrators, however, were appointed by and were subordinate to the Viceroy. The Viceroy also oversaw the most powerful princely rulers: the Nizam of Hyderabad, the Maharaja of Mysore, the Maharaja (Scindia) of Gwalior, the Maharaja of Jammu and Kashmir and the Gaekwad (Gaekwar) Maharaja of Baroda. The remaining princely rulers were overseen either by the Rajputana Agency and Central India Agency, which were headed by representatives of the Viceroy, or by provincial authorities.

text: The Chamber of Princes was an institution established in 1920 by a Royal Proclamation of King-Emperor George V to provide a forum in which the princely rulers could voice their needs and aspirations to the government. The chamber usually met only once a year, with the Viceroy presiding, but it appointed a Standing Committee, which met more often.

text: Upon independence in August 1947, the title of Viceroy was abolished. The representative of the British Sovereign became known once again as the Governor-General. C. Rajagopalachari became the only Indian Governor-General. However, once India acquired independence, the Governor-General's role became almost entirely ceremonial, with power being exercised on a day-to-day basis by the Indian cabinet. After the nation became a republic in 1950, the President of India continued to perform the same functions.

text: Council[edit]

text: The Governor-General was always advised by a Council on the exercise of his legislative and executive powers. The Governor-General, while exercising many functions, was referred to as the "Governor-General in Council."

text: The Regulating Act 1773 provided for the election of four counsellors by the East India Company's Court of Directors. The Governor-General had a vote along with the counsellors, but he also had an additional vote to break ties. The decision of the Council was binding on the Governor-General.

text: In 1784, the Council was reduced to three members; the Governor-General continued to have both an ordinary vote and a casting vote. In 1786, the power of the Governor-General was increased even further, as Council decisions ceased to be binding.

text: The Charter Act 1833 made further changes to the structure of the Council. The Act was the first law to distinguish between the executive and legislative responsibilities of the Governor-General. As provided under the Act, there were to be four members of the Council elected by the Court of Directors. The first three members were permitted to participate on all occasions, but the fourth member was only allowed to sit and vote when legislation was being debated.

text: In 1858, the Court of Directors ceased to have the power to elect members of the Council. Instead, the one member who had a vote only on legislative questions came to be appointed by the Sovereign, and the other three members by the Secretary of State for India.

text: The Indian Councils Act 1861 made several changes to the Council's composition. Three members were to be appointed by the Secretary of State for India, and two by the Sovereign. (The power to appoint all five members passed to the Crown in 1869). The Viceroy was empowered to appoint an additional six to twelve members (changed to ten to sixteen in 1892, and to sixty in 1909). The five individuals appointed by the Sovereign or the Indian Secretary headed the executive departments, while those appointed by the Viceroy debated and voted on legislation.

text: In 1919, an Indian legislature, consisting of a Council of State and a Legislative Assembly, took over the legislative functions of the Viceroy's Council. The Viceroy nonetheless retained significant power over legislation. He could authorise the expenditure of money without the Legislature's consent for "ecclesiastical, political [and] defense" purposes, and for any purpose during "emergencies." He was permitted to veto, or even stop debate on, any bill. If he recommended the passage of a bill, but only one chamber cooperated, he could declare the bill passed over the objections of the other chamber. The Legislature had no authority over foreign affairs and defence. The President of the Council of State was appointed by the Viceroy; the Legislative Assembly elected its President, but the election required the Viceroy's approval.

text: Style and title[edit]

text: Until 1833, the title of the position was "Governor-General of Bengal". The Government of India Act 1833 converted the title into "Governor-General of India." The title "Viceroy and Governor-General" was first used in the queen's proclamation appointing Viscount Canning in 1858.[3] It was never conferred by an act of parliament, but was used in warrants of precedence and in the statutes of knightly orders. In usage, "viceroy" is employed where the governor-general's position as the monarch's representative is in view.[4] The viceregal title was not used when the sovereign was present in India. It was meant to indicate new responsibilities, especially ritualistic ones, but it conferred no new statutory authority. The governor-general regularly used the title in communications with the Imperial Legislative Council, but all legislation was made only in the name of the Governor-General-in-Council (or the Government of India).[5]

text: The Governor-General was styled Excellency and enjoyed precedence over all other government officials in India. He was referred to as 'His Excellency' and addressed as 'Your Excellency'. From 1858 to 1947, the Governor-General was known as the Viceroy of India (from the French roi, meaning 'king'), and wives of Viceroys were known as Vicereines (from the French reine, meaning 'queen'). The Vicereine was referred to as 'Her Excellency' and was also addressed as 'Your Excellency'. Neither title was employed while the Sovereign was in India. However, the only reigning British Sovereign to visit India during the period of British rule was King George V, who accompanied by his consort Queen Mary attended the Delhi Durbar in 1911.[citation needed]

text: When the Order of the Star of India was founded in 1861, the Viceroy was made its Grand Master ex officio. The Viceroy was also made the ex officio Grand Master of the Order of the Indian Empire upon its foundation in 1877.

text: Most Governors-General and Viceroys were peers. Frequently, a Viceroy who was already a peer would be granted a peerage of higher rank, as with the granting of a marquessate to Lord Reading and an earldom and later a marquessate to Freeman Freeman-Thomas. Of those Viceroys who were not peers, Sir John Shore was a baronet, and Lord William Bentinck was entitled to the courtesy title 'Lord' because he was the son of a Duke. Only the first and last Governors-General – Warren Hastings and Chakravarti Rajagopalachari – as well as some provisional Governors-General, had no honorific titles at all.

text: Flag[edit]

text: From around 1885, the Viceroy of India was allowed to fly a Union Flag augmented in the centre with the 'Star of India' surmounted by a Crown. This flag was not the Viceroy's personal flag; it was also used by Governors, Lieutenant Governors, Chief Commissioners and other British officers in India. When at sea, only the Viceroy flew the flag from the mainmast, while other officials flew it from the foremast.

text: From 1947 to 1950, the Governor-General of India used a dark blue flag bearing the royal crest (a lion standing on the Crown), beneath which was the word 'India' in gold majuscules. The same design is still used by many other Commonwealth Realm Governors-General. This last flag was the personal flag of the Governor-General only.

text: Residence[edit]

text: The Governor-General of Fort William resided in Belvedere House, Calcutta, until the early nineteenth century, when Government House was constructed. In 1854, the Lieutenant Governor of Bengal took up residence there. Now, the Belvedere Estate houses the National Library of India.

text: Lord Wellesley, who is reputed to have said that 'India should be governed from a palace, not from a country house', constructed a grand mansion, known as Government House, between 1799 and 1803. The mansion remained in use until the capital moved from Calcutta to Delhi in 1912. Thereafter, the Lieutenant Governor of Bengal, who had hitherto resided in Belvedere House, was upgraded to a full Governor and transferred to Government House. Now, it serves as the residence of the Governor of the Indian state of West Bengal, and is referred to by its Bengali name Raj Bhavan.

text: After the capital moved from Calcutta to Delhi, the Viceroy occupied the newly built Viceroy's House, designed by Sir Edwin Lutyens. Though construction began in 1912, it did not conclude until 1929; the palace was not formally inaugurated until 1931. The final cost exceeded £877,000 (over £35,000,000 in modern terms) – more than twice the figure originally allocated. Today the residence, now known by the Hindi name of 'Rashtrapati Bhavan', is used by the President of India.

text: Throughout the British administration, Governors-General retreated to the Viceregal Lodge (Rashtrapati Niwas) at Shimla each summer to escape the heat, and the government of India moved with them. The Viceregal Lodge now houses the Indian Institute of Advanced Study.

text: Insignia[edit]

text:
Badge of the Governor-General (1885–1947)

Standard of the Governor-General (1885–1947)

Standard of the Governor-General (1947–50)