Gilbert T. Walker
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Sir Gilbert Thomas Walker (14 June 1868 – 4 November 1958) was an English
physicist A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe. Physicists generally are interested in the root or ultimate caus ...
and
statistician A statistician is a person who works with theoretical or applied statistics. The profession exists in both the private and public sectors. It is common to combine statistical knowledge with expertise in other subjects, and statisticians may wor ...
of the 20th century. Walker studied mathematics and applied it to a variety of fields including
aerodynamics Aerodynamics, from grc, ἀήρ ''aero'' (air) + grc, δυναμική (dynamics), is the study of the motion of air, particularly when affected by a solid object, such as an airplane wing. It involves topics covered in the field of fluid dyn ...
,
electromagnetism In physics, electromagnetism is an interaction that occurs between particles with electric charge. It is the second-strongest of the four fundamental interactions, after the strong force, and it is the dominant force in the interactions of a ...
and the analysis of time-series data before taking up a teaching position at the University of Cambridge. Although he had no experience in meteorology, he was recruited for a post in the Indian Meteorological Department where he worked on statistical approaches to predict the monsoons. He developed the methods in the analysis of time-series data that are now called the Yule-Walker equations. He is known for his groundbreaking description of the Southern Oscillation, a major phenomenon of global
climate Climate is the long-term weather pattern in an area, typically averaged over 30 years. More rigorously, it is the mean and variability of meteorological variables over a time spanning from months to millions of years. Some of the meteorologic ...
, and for discovering what is named after him as the Walker circulation, and for greatly advancing the study of climate in general. He was also instrumental in aiding the early career of the Indian mathematical prodigy,
Srinivasa Ramanujan Srinivasa Ramanujan (; born Srinivasa Ramanujan Aiyangar, ; 22 December 188726 April 1920) was an Indian mathematician. Though he had almost no formal training in pure mathematics, he made substantial contributions to mathematical analysis ...
.


Early life and education

He was born in
Rochdale Rochdale ( ) is a large town in Greater Manchester, England, at the foothills of the South Pennines in the dale on the River Roch, northwest of Oldham and northeast of Manchester. It is the administrative centre of the Metropolitan Borough ...
,
Lancashire Lancashire ( , ; abbreviated Lancs) is the name of a historic county, ceremonial county, and non-metropolitan county in North West England. The boundaries of these three areas differ significantly. The non-metropolitan county of Lancashi ...
on 14 June 1868, the fourth child and eldest son of Thomas Walker and Elizabeth Charlotte Haslehurst. Thomas was Borough Engineer of Croydon and had pioneered the use of concrete for town reservoirs. He attended
Whitgift School ("He who perseveres, conquers") , established = , closed = , type = Independent school , religious_affiliation = Church of England , president = , head_label = Head Master , head = Christopher Ramsey , c ...
where he showed an interest in mathematics and got a scholarship to study at St Paul's School. He attended
Trinity College, Cambridge Trinity College is a constituent college of the University of Cambridge. Founded in 1546 by Henry VIII, King Henry VIII, Trinity is one of the largest Cambridge colleges, with the largest financial endowment of any college at either Cambridge ...
where he was Senior Wrangler in 1889. His hard studies led to ill-health and he spent several winters recuperating in Switzerland where he learnt skating and became quite expert. He became a lecturer at Trinity College from 1895.


Career

Henry Francis Blanford Henry Francis Blanford (sometimes spelt Blandford) (3 June 1834 – 23 January 1893) was a British meteorologist and palaeontologist who worked in India. He was a younger brother of the naturalist William Thomas Blanford, both of whom joined t ...
, the founding director of the Indian Meteorological Department, had noticed the pattern that the summer monsoon in India and Burma was correlated with the spring snow cover in the Himalayas and it became a routine to use this to make predictions on the Indian monsoons. By 1892 however, these predictions began to fail and the second director John Eliot began to use several other correlations including strength of the trade winds, anticyclones, Nile floods and date from Australia and Africa. Eliot's forecasts from 1899 to 1901 failed so badly, with a drought and famine when he predicted higher than normal rains, that he was criticized severely by the newspapers leading to forecasts being made confidential from 1902 to 1905. A growing interest in the work of Lockyer on cycles led him to choose a mathematically inclined successor who would be Walker, despite the lack of experience in meteorology. Eliot himself was an able mathematician, a
Second Wrangler At the University of Cambridge in England, a "Wrangler" is a student who gains first-class honours in the final year of the university's degree in mathematics. The highest-scoring student is the Senior Wrangler, the second highest is the Secon ...
at Cambridge, while Walker had been a Senior Wrangler. Walker was an established applied mathematician at the
University of Cambridge , mottoeng = Literal: From here, light and sacred draughts. Non literal: From this place, we gain enlightenment and precious knowledge. , established = , other_name = The Chancellor, Masters and Schola ...
and gave up a Fellowship at Trinity to take up a position as assistant to the meteorological reporter in 1903. He was elevated to the position of director general of observatories in India in 1904. Walker developed Blanford's idea with quantitative rigour and came up with correlation measures (with a lag) and regression equations (in time-series terminology,
autoregression In statistics, econometrics and signal processing, an autoregressive (AR) model is a representation of a type of random process; as such, it is used to describe certain time-varying processes in nature, economics, etc. The autoregressive model spe ...
). He set up a group of Indian clerks to calculate correlations between weather parameters. The methods he introduced for time-series regression are now partly named after him (the other contributor was Udny Yule who studied sun-spot cycles) as the Yule-Walker equations. Analyzing vast amounts of weather data from India and lands beyond, over the next fifteen years he published the first descriptions of the great seesaw oscillation of
atmospheric An atmosphere () is a layer of gas or layers of gases that envelop a planet, and is held in place by the gravity of the planetary body. A planet retains an atmosphere when the gravity is great and the temperature of the atmosphere is low. A s ...
pressure Pressure (symbol: ''p'' or ''P'') is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. Gauge pressure (also spelled ''gage'' pressure)The preferred spelling varies by country and e ...
between the Indian and
Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the continen ...
, and its correlation to
temperature Temperature is a physical quantity that expresses quantitatively the perceptions of hotness and coldness. Temperature is measured with a thermometer. Thermometers are calibrated in various temperature scales that historically have relied o ...
and
rain Rain is water droplets that have condensed from atmospheric water vapor and then fall under gravity. Rain is a major component of the water cycle and is responsible for depositing most of the fresh water on the Earth. It provides water f ...
fall patterns across much of the Earth's tropical regions, including India. This is now called the
El Niño Southern Oscillation EL, El or el may refer to: Religion * El (deity), a Semitic word for "God" People * EL (rapper) (born 1983), stage name of Elorm Adablah, a Ghanaian rapper and sound engineer * El DeBarge, music artist * El Franco Lee (1949–2016), American po ...
. He was made a Companion of the
Order of the Star of India The Most Exalted Order of the Star of India is an order of chivalry founded by Queen Victoria in 1861. The Order includes members of three classes: # Knight Grand Commander (GCSI) # Knight Commander ( KCSI) # Companion ( CSI) No appointments ...
in 1911. Walker took an interest in several other fields. He made mathematical studies on bird flight and boomerangs. An interest in boomerangs as an undergraduate had earned him the nickname of "Boomerang Walker". In
Shimla Shimla (; ; also known as Simla, List of renamed Indian cities and states#Himachal Pradesh, the official name until 1972) is the capital and the largest city of the States and union territories of India, northern Indian state of Himachal Prade ...
, he used to throw a boomerang on the grounds of Annandale attracting the attention even of the Viceroy of India. He found faults in the ideas on bird flight by
Ernest Hanbury Hankin Ernest Hanbury Hankin (4 February 1865 – 29 March 1939) was an English bacteriologist, aeronautical theorist and naturalist. Working mainly in India, he studied malaria, cholera and other diseases. He is often considered as among the first to ...
, fellow Cambridge scientist at Simla, and pointed out that ascending thermals had enough energy to support the soaring of birds and also pointed out the role of turbulent eddies in providing lift. He published a summary of his ten years of research in ''Nature'' in 1901. He was an accomplished flute player and took an interest in the physics of the flute. He was also an expert on the history and evolution of the flute. He made some design changes to flutes and these went into manufacture. He was also a watercolour artist and while at Simla, held an exhibition of his works.


Retirement to England

Walker continued his studies of yearly weather and climate change even after his retirement from India (in 1924 when he was knighted) and acceptance of a professorship in meteorology at
Imperial College London Imperial College London (legally Imperial College of Science, Technology and Medicine) is a public research university in London, United Kingdom. Its history began with Prince Albert, consort of Queen Victoria, who developed his vision for a cu ...
. He had only mixed success in his original goal, the prediction of monsoonal failures; however, his theories and broad body of supporting research represented an invaluable step forward, allowing his successors in climate study to move beyond local observation and forecasting toward comprehensive models of climate worldwide. He served as president of the
Royal Meteorological Society The Royal Meteorological Society is a long-established institution that promotes academic and public engagement in weather and climate science. Fellows of the Society must possess relevant qualifications, but Associate Fellows can be lay enthus ...
from 1926 to 1927. Walker was elected a Fellow of the Royal Society in 1904, long before his work on meteorology on the strength of his work in applied mathematics and applications to electromagnetism. Walker, with his talent for mathematics, was among the first to recognize the abilities of the Indian mathematical prodigy
Srinivasa Ramanujan Srinivasa Ramanujan (; born Srinivasa Ramanujan Aiyangar, ; 22 December 188726 April 1920) was an Indian mathematician. Though he had almost no formal training in pure mathematics, he made substantial contributions to mathematical analysis ...
and wrote a letter to the University of Madras to support a scholarship. Walker's interest in a wide range of subjects made him note the growing insularity of specialists: Walker married Mary Constance Carter in 1908 and they had a son, Michael Ashley, and a daughter, Verity Micheline. He died at Coulsdon,
Surrey Surrey () is a ceremonial and non-metropolitan county in South East England, bordering Greater London to the south west. Surrey has a large rural area, and several significant urban areas which form part of the Greater London Built-up Area. ...
on 4 November 1958. He was 90 years old. The Walker Institute in the United Kingdom, established to study climate, is named in his honour.


Publications

Publications related to Indian meteorology: * Correlation in seasonal variations in climate (Introduction). Memoirs of the India Meteorological Department 20(6): * On the meteorological evidence for supposed changes of climate in India. Memoirs of the India Meteorological Department 21(1): * Correlation in seasonal variations of weather. II. Memoirs of the India Meteorological Department 21(2) * Data of heavy rainfall over short periods in India. Memoirs of the India Meteorological Department 21(3) * The liability to drought in India as compared with that in other countries. Memoirs of the India Meteorological Department 21(5) * (with Rai Bahadur Hem Raj). The cold weather storms of northern India. Memoirs of the India Meteorological Department 21(7) * A further study of relationships with Indian monsoon rainfall. Memoirs of the India Meteorological Department 21(8). * Correlation in seasonal variations of weather, III. Memoirs of the India Meteorological Department 21(9) * Correlation in seasonal variations of weather, IV, sunspots and rainfall. Memoirs of the India Meteorological Department 21(10). * Correlation in seasonal variations of weather, V, sunspots and temperature. Memoirs of the India Meteorological Department 21(11) * Correlation in seasonal variations of weather, VI, sunspots and pressure. Memoirs of the India Meteorological Department 21(12) * Monthly and annual rainfall normals. Memoirs of the India Meteorological Department 22(1) * Monthly an annual normals of number of rainy days. Memoirs of the India Meteorological Department 22(2) * Monthly and annual normals of pressure, temperature, relative humidity, vapour tension and cloud. Memoirs of the India Meteorological Department 22(3) * Correlation in seasonal variations of weather, VII, the local distribution of monsoon rainfall. Memoirs of the India Meteorological Department 23(2) * Monthly and annual normal rainfall and of rainy days. Memoirs of the India Meteorological Department 23(7) * Frequency of heavy rain in India. Memoirs of the India Meteorological Department 23(8) * Correlation in seasonal variations of weather, VIII, preliminary study of world weather. Memoirs of the India Meteorological Department 24(4) * Correlation in seasonal variations of weather, IX, a further study of world weather. Memoirs of the India Meteorological Department 24(9) * Correlation in seasonal variations of weather, X, applications to seasonal forecasting in India. Memoirs of the India Meteorological Department 24(10) * (with T.C. Kamesvara Rao) Rainfall types in India in the cold weather period, December to March 1915. Memoirs of the India Meteorological Department 24(11) Publications on methodology: * Other topics: * (1896) On a dynamical top. Q. J. Pure Appl. Math. 28:175–184. * (1895) Walker G.T. On a Curious Dynamical Property of Celts // Proc. Cambridge Phil. Soc. 1895. Vol. 8, Pt. 5. P. 305–306.


See also

* Centers of action *
Rattleback A rattleback is a semi-ellipsoidal top which will rotate on its axis in a preferred direction. If spun in the opposite direction, it becomes unstable, "rattles" to a stop and reverses its spin to the preferred direction. This spin-reversal appear ...
*
Teleconnection Teleconnection in atmospheric science refers to climate anomalies being related to each other at large distances (typically thousands of kilometers). The most emblematic teleconnection is that linking sea-level pressure at Tahiti and Darwin, Austr ...


References


External links


Biography of Walker from The Walker Institute
{{DEFAULTSORT:Walker, Gilbert Thomas 1868 births 1958 deaths Academics of Imperial College London English meteorologists Companions of the Order of the Star of India English statisticians Fellows of the Royal Society Knights Bachelor People from Rochdale Presidents of the Royal Meteorological Society Senior Wranglers Alumni of Imperial College London People educated at Whitgift School