NASA Technical Reports Server (NTRS) : Comparing pdf

NASA Technical Reports Server (NTRS) : Comparing

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Validation of satellite remote-sensing methods for estimating rainfall against rain-gauge data is attractive because of the direct nature of the rain-gauge measurements. Comparisons of satellite estimates to rain-gauge data are difficult, however, because of the extreme variability of rain and the fact that satellites view large areas over a short time while rain gauges monitor small areas continuously. In this paper, a statistical model of rainfall variability developed for studies of sampling error in averages of satellite data is used to examine the impact of spatial and temporal averaging of satellite and gauge data on intercomparison results. The model parameters were derived from radar observations of rain, but the model appears to capture many of the characteristics of rain-gauge data as well. The model predicts that many months of data from areas containing a few gauges are required to validate satellite estimates over the areas, and that the areas should be of the order of several hundred km in diameter.

Over gauge arrays of sufficiently high density, the optimal areas and averaging times are reduced. The possibility of using time-weighted averages of gauge data is explored

• Creator/s: NASA Technical Reports Server (NTRS
• Date: 1/1/2002
• Year: 2002
• Book Topics/Themes: NASA Technical Reports Server (NTRS), REMOTE SENSING, SATELLITE OBSERVATION, METEOROLOGICAL SATELLITES, RAIN GAGES, ESTIMATES, MATHEMATICAL MODELS, RAIN, METEOROLOGICAL RADAR, VARIABILITY, Bell, Thomas L., Kundu, Prasun K

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