Papers by Francois Becker
History of Geo- and Space Sciences, 2020
The scientific career of Michael Rycroft (born in 1938) spans the space age, during which signifi... more The scientific career of Michael Rycroft (born in 1938) spans the space age, during which significant changes have occurred in how scientists work, experiment, and interact. Here, as part of his 80th birthday celebrations, we review his career to date in terms of the social and structural changes in collaborative international science. His contributions to research, teaching, and management across solar-terrestrial and ionospheric physics as well as atmospheric and space science are also discussed. 2 Education-scientific training at Cambridge Following a first degree in physics at Imperial College London, Michael Rycroft was amongst the first cohort of post-Published by Copernicus Publications. 106 K. L. Aplin et al.: Michael Rycroft at 80 graduate students to arrive at the newly founded Churchill College in Cambridge in 1960. He was registered with the university for a PhD in the Meteorological Physics Group at the Cavendish Laboratory under the supervision of Dr. Thomas W. (Will) Wormell. 2.1 Meteorological physics at Cambridge before 1960 Atmospheric physics, or meteorological physics as the research group was named, at Cambridge, had a long and distinguished history, mainly due to the influence of Charles Thomas Rees Wilson (who was always known as "CTR"). CTR's career was dominated by a fascination with atmospheric science and, in particular, atmospheric electricity, which had been triggered by a 2-week stay at Ben Nevis Observatory in 1894. The cloud chamber, which earned CTR the 1927 Nobel Prize, was an attempt to recreate phenomena he had seen on Ben Nevis. Despite the significance of the cloud chamber for particle physics and the huge research effort it triggered at Cambridge and elsewhere, CTR worked exclusively on atmospheric electricity for the rest of his long life, between Cambridge's Cavendish Laboratory and its Solar Physics Observatory located west of the town centre on Madingley Road (Harrison, 2011). Even by the standards of the time, CTR had relatively few co-workers, due to his "shy and very modest" personality (Dee and Wormell, 1963). Philip Dee, one of his few postgraduate students, even suggested that CTR had moved to the observatory: "nominally, he always claimed, to get away from the radioactive contamination in the Cavendish, but I suspect in order to live in a quieter atmosphere" (Dee, 1971). This meant that CTR's research programme developed relatively slowly at Cambridge. An Indian student, Prasanta Chandra Malhanobis, was recruited before the onset of World War I but was in India when war broke out and never returned. CTR's next PhD student was Wormell, taken on about the same time as Cecil Powell in 1925; Wormell "started on some experiments on thunderstorms in which Wilson had been interested for many years.. . " (Powell, undated; reproduced in 1987), obtaining his PhD on the electrical properties of rain in 1929 (Wormell, 1929). (A student contemporary of Wormell at Cambridge, John Alan Chalmers, began similar experiments at Durham after his own PhD, establishing a strong and enduring base for atmospheric electricity in the North of England (Aplin, 2018).) Wormell worked at the Solar Physics Observatory for many years and developed broad interests in atmospheric physics, before becoming university lecturer in meteorological physics at the Cavendish Laboratory in 1950 (Longair, 2016). It was this research group, at that time with around six members, that Michael Rycroft joined in 1960. Rycroft's colleagues included Desmond Walshaw, a senior researcher in atmospheric infrared absorption, who supervised students
Physics and Chemistry of the Earth, 1995
Remote sensing instruments aboard satellites observe the properties (e.g., intensity) of electrom... more Remote sensing instruments aboard satellites observe the properties (e.g., intensity) of electromagnetic radiation (e.g., from the Sun) backscattered and/or emitted by the surface. Thus, they record some information about the surface. Different information is obtained in the visible/near infrared, thermal infrared and microwave parts of the spectrum.
Il Nuovo Cimento B Series 10, 1970
ot positive pions by deuteron is studied in a theory based on a Lagrangian formahsm for the =-3~ ... more ot positive pions by deuteron is studied in a theory based on a Lagrangian formahsm for the =-3~ interaction. Total cross-section, angular distribution and polarization are estimated from threshold to 300 MeV pion kinetic energy. Starting from the nonrelativistie limi~ of the PS(PV) :z-3~ interaction we take into account the Born term, the forward and backward rescattering pion terms, as well as the nucleon-nucleon rescattering in final state. We use different wave functions for the deuteron and for the two-proton final state which differ only at short distances. Conclusions are drawn about the sensitivity of theoretical results to the behaviour of J~°JW wave functions at short distances. The results are compared to experimental data.
Nuclear Physics B, 1970
The double charge exchange of rr-mesons on 4He is analysed in the framework of a model which assu... more The double charge exchange of rr-mesons on 4He is analysed in the framework of a model which assumes that the process takes place on a pair of nucleons of the target. The double differential cross section d2cr/dEd~, the differential cross section d~/d~ and the total cross section c~ for this process are calculated and compared with the available experimental data. the behaviour of \xhieh is generally explained. The shape of the wave functions is discussed and some conclusions are drawn on the relative influence of the a,a ~ resonance and of the SoNN resonance on the results. In the comparison between all the available experimental data. some discrepancies are observed and discussed.
Nuclear Physics A, 1974
Abstract In this paper we give a generalisation of the model of nuclear reactions proposed by Von... more Abstract In this paper we give a generalisation of the model of nuclear reactions proposed by Von Oertzen in the framework of molecular orbitals. The different equations leading to the cross section are derived and discussed. It turns out that the helicity scheme is the most appropriate one. Some emphasis is given to reactions, including elastic scattering and elastic transfer for which this approach is well suited. We discuss both the unadiabatic and Coriolis coupling terms which appear in the equations, and we show how these terms are partly cancelled if one takes into account one part of the recoil effect.
International Journal of Remote Sensing, 1992
The difference of vertically and horizontally polarized brightness temperatures (referred to here... more The difference of vertically and horizontally polarized brightness temperatures (referred to here as the polarization difference, δT) observed at 37GHz frequency of the scanning multi-channel microwave radiometer (SMMR) on board the Nimbus-7 satellite and special sensor microwave imager (SSM/I) on board the DMSP-F8 satellite could provide useful information about land surface change within the span of these global observations, November
… Canaria 10, 11 y 12 de …, 1998
En el presente trabajo se ha realizado un estudio comparativo entre la técnica multiangular y la ... more En el presente trabajo se ha realizado un estudio comparativo entre la técnica multiangular y la corrientemente usada técnica bicanal (método splitwindow), para determinar la temperatura de la superficie de la tierra (LST) y del mar(SSP. Los valores numéricos de los coeficientes, se han calculado a partir de simulaciones de las medidas realizadas por los canales 3 (11 µm) y 4 (12 µm) del ATSR. Con este fin, se propone una ecuación monocanal de tipo biangular, que relaciona la temperatura de la superficie con las temperaturas radiométricas, medidas en las dos vistas de interés (ATSR nadir y forward). Los resultados muestran que la técnica biangular permite estimar la SST con un error de 0,3 K. Además, para la determinación de la LST, se confirman las ventajas del método biangular, siempre que la variación espectral y angular de la emisividad sean del mismo orden de magnitud.
Agricultural and Forest Meteorology, 1995
A consistent nomenclature for thermal infrared remote sensing of natural surfaces is outlined in ... more A consistent nomenclature for thermal infrared remote sensing of natural surfaces is outlined in this paper. Terms such as 'canopy temperature' and 'surface temperature' should be confined to general, qualitative descriptions and terms such as directional radiometric temperature, hemispherical emissivity, aerodynamic temperature, or hemispherical-directional reflectance used for technical precision. Some discussion also is included on the relation between hemispherical-directional thermal reflectance and directional thermal emissivity. A distinction is made between two kinds of emissivity; e-emissivity and r-emissivity. Through use of detailed models of directional thermal emissivity and bidirectional reflectance, we suggest that the influence of temperature gradients in vegetation on directional emissivity usually will cause uncertainties of less than 0.005. In addition, uncertainties that occur in estimating surface temperature, which arise because an ensemble of black bodies each at a different temperature does not have a black body radiance distribution with temperature, will not always be negligible for purposes of remote sensing of natural surfaces. Differences between mean thermodynamic and ensemble radiometric temperatures of 1 K or larger are possible even though differences in ensemble radiometric temperatures for different wavelength bands in the atmospheric window (8-14 p,rn) usually will be less than 0.1 K.
Remote Sensing of Environment, 1999
The current LTersion completely supersedes the previously published version, which should be disr... more The current LTersion completely supersedes the previously published version, which should be disregarded. The publishers ' LSIIT/CNRS(UPRESA-7005),
Http Dx Doi Org 10 1080 01431169008955028, May 16, 2007
Recently Li and McDonnell (1988) have used such a method to evaluate SST using only the known atm... more Recently Li and McDonnell (1988) have used such a method to evaluate SST using only the known atmospheric pressure, temperature and relative humidity at the ground level. They have also pointed out that retrieved SS,Ts agree with available in situ measurements with a ...
International Journal of Remote Sensing, 1987
... (29a) Page 8. 1516 F. Becker (30) ... RMS error 1·13 1·37 0·88 0·97 Table 2 (b). Comparison b... more ... (29a) Page 8. 1516 F. Becker (30) ... RMS error 1·13 1·37 0·88 0·97 Table 2 (b). Comparison between the results offormula (22) (last column) and the results of the algorithms of Barton (I 985)(3rd column) and McClain (1984) (4th column) quoted from Barton and Takashima (1986). ...
High Spectral Resolution Infrared Remote Sensing for Earth’s Weather and Climate Studies, 1993
Remote Sensing of Environment, 1990
... 20:209-235. Gillespie, AR, Kahle, AB, and Walker, RE (1987), Color enhancement of highly corr... more ... 20:209-235. Gillespie, AR, Kahle, AB, and Walker, RE (1987), Color enhancement of highly correlated images. ... Susskind, J., Rosenfield, J., Renter, D., and Chahine, MT (1984), Remote sensing of weather and climate parameters from HIRS2/MSU on TIROS-N, J. Geophys. Res. ...
Remote Sensing of Environment, 1993
The surface temperature and emissivity of natural media are very useful to know for many applicat... more The surface temperature and emissivity of natural media are very useful to know for many applications. In this article, we show that the scheme proposed in our previous work to retrieve both the spectral emissivities and land surface temperature from AVHRR data is feasible. ...
Remote Sensing of Environment, 1988
... 311 (1988) Relative Sensitivity of Normalized Difference Vegetation Index (NDVI) and Microwav... more ... 311 (1988) Relative Sensitivity of Normalized Difference Vegetation Index (NDVI) and Microwave Polarization Difference Index (MPDI) for Vegetation and Desertification Monitoring 297 FRANCOIS BECKER and BHASKAR J. CHOUDHURY ... ISLSCP Conf., ESA SP-248:349-353. ...
International Journal of Remote Sensing, 1990
Recently Li and McDonnell (1988) have used such a method to evaluate SST using only the known atm... more Recently Li and McDonnell (1988) have used such a method to evaluate SST using only the known atmospheric pressure, temperature and relative humidity at the ground level. They have also pointed out that retrieved SS,Ts agree with available in situ measurements with a ...
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Papers by Francois Becker