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...ial resolution of 156.25 km 2 (footprint of 12.5 km). The rain signature needs to be separated from other surfaces exhibiting similar characteristics, such as snow cover, deserts and semiarid regions =-=[22,26]-=-. Overviews of the varying techniques for rainfall retrieval from the SSM/I are presented by [27,28]. Many of the algorithms suffered from the improper delineation of rain areas from other surfaces th...

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...enotes areas of significant 85-GHz ice scattering. Surface snow cover can scatter microwave radiation to produce 85-GHz brightness temperatures similar to those associated with precipitating systems (=-=Grody 1991-=-; Ferraro et al. 1994). In the Tropics, this is a concern in high-elevation regions such as the Andes Mountains where permanent or semipermanent snow cover may exist. Actual precipitating areas with 8...

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... soil moisture of the land surface, and emissions vary significantly with time and location. Therefore, variations in the observed brightness temperature caused by land surface conditions must be distinguished from variations caused by precipitation. Land surfaces covered by desert sand or fallen snow produce lower brightness temperatures because sand and snow particles on the ground scatter microwave radiation at a higher frequency. If this phenomenon is not distinguished from scattering by solid precipitation, it leads to false estimates of rainfall over desert and snow-covered areas. Thus, Grody (1991) proposed a method to separate desert sand and fallen snow from precipitation utilizing brightness temperatures observed at a lower frequency by the Special Sensor Microwave Imager (SSM/I) of the Defense Meteorological Satellite Program. This idea was adopted in rain/no-rain classification (RNC) methods to preprocess rainfall retrieval algorithms, such as the Goddard scattering algorithm (GSCAT) (Adler et al. 1994), Ferraro et al. (1994), Ferraro (1997), Kummerow and Giglio (1994), and the Goddard profiling algorithm (GPROF) (Kummerow et al. 1996, 2001), with some modifications. In this study,...

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...rithm uses a combination of the 19- and 21-GHz channels to accomplish this goal as seen in Eq. (14). The vertical polarization is used to reduce the sensitivity to emissivity changes over land areas (=-=Grody 1991-=-). 2) IMPROVED COLD SURFACE SCREENING In addition to modifying the estimated rainfall rates, however, a new procedure was developed to better classify (‘‘screen’’) each land pixel as ‘‘raining,’’ ‘‘no...

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... providing estimates in regions with frozen or icy surfaces [Huffman and Bolvin, 2013]. The snow cover in winter very likely interferes with the PMW-based retrievals (i.e., HQ) [Ferraro et al., 1998; =-=Grody, 1991-=-], such as AMSR-E and AMSU-B with coverage of higher-latitude bands (beyond 38N-S). The high frequency channels (89 and 150 GHz) of AMSU-B might detect more scattering associated with precipitation-s...

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...ensing over the ocean and provide essential inputs to numerical weather prediction models. SSM/I data have also been used for land and ice studies, including measurements of snow cover classification =-=[4]-=-, soil and plant moisture content [8], [15], atmospheric moisture over land [10], land surface temperature [12], and mapping polar ice [18]. Because the surface brightness observed by the SSM/I may be...

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... 2001), where the physics of the algorithm relies on both emission-based (e.g., Wilheit et al. 1977, 1991; Prabhakara et al. 1992) and scattering-based (e.g., Spencer et al. 1989; Mugnai et al. 1990; =-=Grody 1991-=-; 1 The TRMM satellite was boosted from a nominal altitude of 350 km to an altitude of 402.5 km during August of 2001 for fuel savings. This ‘‘boost’’ resulted in a decrease in the areal resolution of...