caa a22 4500 46905266X CHVBK 20180323132834.0 cr unu---uuuuu 170328e19920601xx s 000 0 eng 10.1007/BF01025616 doi (NATIONALLICENCE)springer-10.1007/BF01025616 Rainfall over oceans: Remote sensing from satellite microwave radiometers [Elektronische Daten] [C. Prabhakara, G. Dalu, R. Suhasini, J. Nucciarone, G. Liberti] Summary: Microwave radiometer brightness temperature (T b) measurements obtained from satellites over the oceans in dual polarization, at frequencies ranging from 6.6 to 85 GHz, reveal information about the rain and precipitation sized ice. These multifrequency measurements are composited from observations made by the Scanning Multichannel Microwave Radiometer (SMMR) and the Special Sensor Microwave/Imager (SSM/I). TheT b measurements at 37 GHz, having a field of view (fov) of about 30 km, show relatively strong emissions due to rain, reaching values as large as 260 K over the tropical and mid-latitude rainbelts. Only marginal effects due to scattering by ice above the rain clouds are revealed. At frequencies below 37 GHz, where the fov is much larger than 30 km and the extinction is weaker,T b is significantly smaller than 260 K. Additional information content about rain, at these low frequencies, is not appreciable. On the other hand, at 85 GHz (fov ≅15 km), where the extinction is very strong, the sea surface below the clouds is often masked and scattering due to ice above the rain clouds is vividly noticed. However, these high frequency measurements do not yield direct information about rain below the clouds. Recognizing the above merits inherent in the 37 GHz observations the SMMR and SSM/I data at this frequency are utilized to develop and empirical method to retrieve rain rate over oceans. In this method it is assumed that over an oceanic area, the statistics of the observedT b must be derivable from the statistics of the corresponding rain rates. Furthermore, the underestimation of rain rate, arising from the inability of the radiometer to respond sensitively to rain above a given threshold is empirically rectified with the help of two parameters that depend on the total water vapor content in the atmosphere. Rain rates deduced over the oceans around Japan using the SSM/I data, when compared with those measured by radars that are calibrated against rain gauges, show a good correlation; there is, however, a systematic overestimation. Seasonal mean maps of the rainfall over the global oceans based on SMMR data compare favorably with climatological rain maps over the Atlantic and Pacific Oceans developed by Dorman and Bourke (1979, 1981). Springer-Verlag, 1992 Prabhakara C. NASA/Goddard Space Flight Center, Code 913, 20771, Greenbelt, MD, USA aut Dalu G. Istituto di Fisica dell'Atmosfera, Rome, Italy aut Suhasini R. USRA, NASA/Goddard Space Flight Center, Greenbelt, USA aut Nucciarone J. Hughes-STX Corporation Lanham, USA aut Liberti G. Istituto di Fisica dell'Atmosfera, Rome, Italy aut Meteorology and Atmospheric Physics Springer-Verlag 47/2-4(1992-06-01), 177-199 0177-7971 47:2-4<177 1992 47 703 https://doi.org/10.1007/BF01025616 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF01025616 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Prabhakara C. NASA/Goddard Space Flight Center, Code 913, 20771, Greenbelt, MD, USA aut NATIONALLICENCE 700 1- Dalu G. Istituto di Fisica dell'Atmosfera, Rome, Italy aut NATIONALLICENCE 700 1- Suhasini R. USRA, NASA/Goddard Space Flight Center, Greenbelt, USA aut NATIONALLICENCE 700 1- Nucciarone J. Hughes-STX Corporation Lanham, USA aut NATIONALLICENCE 700 1- Liberti G. Istituto di Fisica dell'Atmosfera, Rome, Italy aut NATIONALLICENCE 773 0- Meteorology and Atmospheric Physics Springer-Verlag 47/2-4(1992-06-01), 177-199 0177-7971 47:2-4<177 1992 47 703 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer