Classification of snow cover and precipitation using the special sensor microwave imager

Abstract

The special sensor microwave imager (SSMI) is a seven-channel microwave radiometer which has dual polarized channels at 19, 37, and 85 GHz and a vertically polarized channel at 22 GHz. A detailed evaluation of all SSMI channels is made in arriving at the optimum channel selection for the global identification of precipitation and snow cover without the use of any ancillary information. The resulting algorithm takes the form of a decision tree which uses the dual polarized channels at 19 GHz and the vertically polarized channels at 22 and 85 GHz. These four channels enable the identification of precipitation from all other atmospheric and surface features, including snow cover.

TRMM 2A12 Land Precipitation Product - Status and Future Plans

“…Over-ocean precipitation retrievals make use of the strong contrast between the warm, un-polarized emission from rainfall and the cold, polarized ocean surface. Both emission-based (Wilheit et al 1977(Wilheit et al , 1991 and scattering-based (Spencer et al 1989;Grody 1991;Ferraro and Marks 1995) methods are utilized. Over land, precipitation retrievals are far more difficult due to the relatively warm and un-polarized nature of the land surface and the high and variable land-surface emissivity.…”

Precipitation characteristics over land from the NOAA‐15 AMSU sensor

“…Thus, the land retrieval is based on the scattering signal of millimeter sized ice hydrometeors in precipitating atmospheres [Wu and Weinman, 1984]. This retrieval method becomes more difficult due to the indirect relationship between volume ice scattering and surface rain rate, and the non-uniqueness of the rain signature from other radiometrically similar surfaces (i.e., snow cover and deserts) [Grody, 1991]. Typically, the rain retrieval has been broken into a two-step process: rain identification and rain rate retrieval.…”

Rainfall detection over northern Algeria by combining MSG and TRMM data

“…The result of MLP is compared with the rain areas delineated by Scatter Index (Grody 1991), which a widely used rain delineation method, to evaluate the performance of this new method.…”

“…According to (Grody 1991), scattering index (SI) is defined as depression in the 85 GHz vertical polarized brightness temperature (T 85V ) due to scattering in the presence of rain. The SI is calculated using three vertically polarized radiances at 19, 21, and 85 GHz.…”