Roger M. Lhermitte (May 28, 1920 – November 21, 2016) was a French meteorologist who "pioneered the development of meteorological Doppler radar."Brown, Rodger A. and Lewis, John M. (2005), BAMS, PATH TO NEXRAD: Doppler Radar Development at the National Severe Storms Laboratory, 86 (10)p 145

/ref> His career extended from the 1950s until his death where he made numerous contributions to the field of radar meteorology resulting in over 100 publications and numerous patents.

Early life and education

Roger Lhermitte was born in Ergal, a hamlet of

Jouars-Pontchartrain Jouars-Pontchartrain () is a commune in the Yvelines department in the Île-de-France region in north-central France. It is approximately 35 kilometres from Paris. This city is famous for the Château de Pontchartrain. Geography The tow ...

in the

Yvelines Yvelines () is a department in the western part of the Île-de-France region in Northern France. In 2019, it had a population of 1,448,207. After the end of the war, Lhermitte continued his education to pursue his doctoral thesis at the Faculté des Sciences de L’Université de Paris under the guidance of Professor Pauthenier. The subject of his thesis work was titled "Contribution à L'Étude des Précipitations Par L’analyse des Échos de Pluies Obtenus à L’aide de Radars" which, roughly translated to English was "Contributions to the study of Precipitations via the Analysis of Radar Data." The thesis begins with the sentence "La presence des gouttes de pluie d'une precipitation provoque la diffusion des ondes centrimetriques et par suite l'apparition d'echos sur les indicateurs des radars utilisant ces longueurs d'onde", which roughly translates to "The presence of precipitation provokes the scattering of centimeter wavelength radiation, which is followed by the appearance of echos on radars using this same wavelength." This is the beginning of decades long research in atmospheric science that led to over 100 publications and numerous patents.

Career

Lhermitte began his career as a scientist at "la Météorologie nationale," first in the city of Trappes, France, and later on Magny-les-Hameaux. Lhermitte first went to North America as a visitor to the Stormy Weather Group in Montreal, QC. He left Paris on January 2, 1955, arriving the next day. There he met Walter Hitcshfeld, J.S. Marshall, K. Gunn and T.East at McGill University. On that trip he met David Atlas whom he would work with in the future. The next year, he visited the Blue Hill Observatory in Boston, MA, making it his first visit to the United States. There he worked with Atlas, R. Donaldson,

Edwin Kessler Edwin Kessler III (December 2, 1928 – February 21, 2017) was an American atmospheric scientist who oversaw the development of Doppler weather radar and was the first director of the National Severe Storms Laboratory (NSSL). Early life Kessler ...

and others. The "early work there led to the installation of the

WSR-57 WSR-57 radars were the primary weather surveillance radar used by the United States for over 35 years. The National Weather Service operated a network of this model radar across the country, watching for severe weather. History The WSR-57 (Wea ...

radar installation network." After these two visits, went back to France and stayed there a few years. After a few visits to North America, Lhermitte emigrated to the United States in January 1961 to work with Atlas at the Air Force Cambridge Research Laboratories (AFCRL). He left the AFCRL for the Sperry Rand Research center in New York, NY in 1963. Some of his work included exploring the use of pulsed Doppler radars to extend the capabilities of conventional Doppler radars in allowing for range discrimination.Lhermitte, Roger M. "Doppler radars as severe storm sensors." Bulletin of the American Meteorological Society 45.9 (1964): 587-596. In 1964

had just become director of National Severe Storms Laboratory (NSSL) and was coordinating efforts to build a weather radar program. He had maintained contact with Roger, and reached out to him to join this new program. Lhermitte left the Sperry Rand Research center in early 1964 for this new venture to work with Kessler, K. Wilk, Dale Sirmans and others. By the end of 1964, they had completed a pulsed 3 cm radar. In early 1967, Lhermitte left the NSSL for the Wave Propagation Laboratory (WPL) in Boulder, CO, at the request of G. Benton who was the director of ERL. He was to work with G. Little on the formation of the Wave Propagation Laboratory (WPL). In 1970, he took a position as a professor at the

Rosenstiel School of Marine, Atmospheric, and Earth Science The Rosenstiel School of Marine, Atmospheric, and Earth Science is the University of Miami's academic and research institution for the study of oceanography, atmospheric sciences, atmospheric, and earth sciences. The Rosenstiel School is locat ...

at the

University of Miami The University of Miami (UM, UMiami, Miami, U of M, and The U) is a private university, private research university in Coral Gables, Florida, United States. , the university enrolled 19,852 students in two colleges and ten schools across over ...

. During his time at the University of Miami, he was the first to develop the 94-GHz doppler radar for the measurement of clouds.Kollias, P., E.E. Clothiaux, M.A. Miller, B.A. Albrecht, G.L. Stephens, and T.P. Ackerman, 2007: Millimeter-Wavelength Radars: New Frontier in Atmospheric Cloud and Precipitation Research. Bull. Amer. Meteor. Soc., 88, 1608–1624, https://doi.org/10.1175/BAMS-88-10-1608 The weather radar was built in 1987.Lhermitte, R., 1987: A 94-GHz Doppler Radar for Cloud Observations. J. Atmos. Oceanic Technol., 4, 36–48, https://journals.ametsoc.org/doi/abs/10.1175/1520-0426%281987%29004%3C0036%3AAGDRFC%3E2.0.CO%3B2 https://doi.org/10.1175/1520-0426(1987)004<0036:AGDRFC>2.0.CO;2] Its design and implementation is described in Lhermitte's 1987 paper "A 94-GHz Doppler Radar for Cloud Observations". The observation by Lhermitte of Mie oscillations in the 94 GHz spectrum paved the way to the measurement of drop size distributions in precipitating clouds. Kollias, P., Albrecht, B. A., & Marks, F. (2002). Why mie? Accurate observations of vertical air velocities and raindrops using a cloud radar. Bulletin of the American Meteorological Society, 83(10), 1471-1483+1438. This was later explored by Pavlos Kollias et al. in a paper entitled "Why Mie?":

Retirement

Lhermitte retired as professor emeritus in the early nineties. Near the end of his career, he decided to write a book on his experiences with centimeter and millimeter wavelength radars in meteorology. It was not written to be a comprehensive review of radars in meteorology, but rather his perspective on it. It contains many original ideas developed by him. Lhermitte died on November 21, 2016, in Miami, Florida.

Contributions to the field of radar meteorology

From an article on the 30th Conference on Radar Meteorology, Roger Lhermitte's contributions as listed

30th Conference on Radar Meteorology (A Tribute to Roger Lhermitte)

The 30th Conference on Radar Meteorology was held in tribute for Lhermitte, who was 82 at the time. An article in Bulletin of the American Meteorological Society, BAMS (2002) describes the tribute:

Publications

Patents

Atmospheric motion non-coherent pulse doppler system
(July 6, 1965)
Method and means of determining variability of atmospheric motion with respect to altitude
(July 27, 1965)
Atmospheric Motion Coherent Pulse Doppler Radar System
(October 12, 1965)
Radar tornado alarm
(September 6, 1966)
Waveform Averaging and Contouring Device For Weather Radars And The Like
(January 30, 1968)

Selected publications

* * Lhermitte, R. (1959), La representation directe du spectre de fluctuation des echos radars donnes par des precipitations, 248, 1554-1556Lhermitte, R. (1959), La representation directe du spectre de fluctuation des echos radars donnes par des precipitations, 248, 1554-1556 * Lhermitte, R. (1958), Sur la fluctuation des echos de precipitations, C. R. Acad. Sci., 246, 1245-1248 * Lhermitte, R. (1957), Sur une method d'observation d'intensite des echos de pluie, C. R. Acad. Sci., 244, 2955-2957 * Lhermitte, R. (1952), Les "bandes superieurs" dans la structure verticale des echos de pluie, C. R. Acad. Sci., 235, 1414-1416Lhermitte, R. (1952), Les "bandes superieurs" dans la structure verticale des echos de pluie, C. R. Acad. Sci., 235, 1414-1416 * Lhermitte, R. (1964) "Doppler radars as severe storm sensors." Bulletin of the American Meteorological Society 45.9 (1964): 587-596 * Lhermitte, R. (1970) "Dual-Doppler radar observation of convective storm circulation." Preprints 14th Conf. Radar Meteor. Tucson, Amer. Meteor. Sco., 139-144Lhermitte, R. (1970) "Dual-Doppler radar observation of convective storm circulation." Preprints 14th Conf. Radar Meteor. Tucson, Amer. Meteor. Sco., 139-144 * Lhermitte, R., and R. Serafin (1984) "Pulse-to-pulse coherent Doppler sonar signal processing techniques," J. Atmos. and Ocean. Technol., vol. 1, pp 293–308Lhermitte, R., and R. Serafin (1984) "Pulse-to-pulse coherent Doppler sonar signal processing techniques," J. Atmos. and Ocean. Technol., vol. 1, pp 293-308 * Lhermitte, R. (1987) "A 94 GHz Doppler Radar for Cloud Observations." J. Atmos. Ocean . Tech., 4 (1), 36‐48 * Lhermitte, R. (1990) "Attenuation and Scattering of Millimeter Wavelength Radiation by Clouds and Precipitation." J. Atmos. Ocean Tech., 7, 464‐479Lhermitte, R. (1990) "Attenuation and Scattering of Millimeter Wavelength Radiation by Clouds and Precipitation." J. Atmos. Ocean Tech., 7, 464‐479

References

{{DEFAULTSORT:Lhermitte, Roger French meteorologists Doppler effects Weather radar pioneers 1920 births 2016 deaths University of Miami faculty