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ISRN Geophysics
Volume 2012 (2012), Article ID 921824, 7 pages
Research Article

Study of Rainfall from TRMM Microwave Imager Observation over India

1Research Center for Environmental Changes, Academia Sinica, Taipei 115, Taiwan
2Remote Sensing & Aerial Surveys, Mission-1B, Geological Survey of India, Govt. of India, Ministry of Mines, Bangalore, India

Received 2 August 2012; Accepted 5 September 2012

Academic Editors: G. Chisham and A. Streltsov

Copyright © 2012 Anoop Kumar Mishra and Rajesh Kumar. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


This paper presents a technique to estimate precipitation over Indian land (6–36°N, 65–99°E) at spatial grid using tropical rainfall measuring mission (TRMM) microwave imager (TMI) observations. It adopts the methodology recently developed by Mishra (2012) to monitor the rainfall over the land portion. Regional scattering index (SI) developed for Indian region and polarization corrected temperature (PCT) have been utilized in this study. These proxy rain variables (i.e., PCT and SI) are matched with rainfall from precipitation radar (PR) to relate rain rate with PCT, SI, and their combination. Retrieval techniques have been developed using nonlinear relationship between rain and proxy variables. The results have been compared with the observations (independent of training data set) from PR. Results have also been validated with the observations from automatic weather station (AWS) rain gauges. It is observed from the validation results that nonlinear algorithm using single variable SI underestimates the low rainfall rates (below 20 mm/h) but overestimates the high rain rates (above 20 mm/h). On the other hand, algorithm using PCT overestimates the high rain rates (above 25 mm/h). Validation results with rain gauges show a CC of 0.68 and RMSE of 4.76 mm when both SI and PCT are used.