Quantitative estimation of orographic precipitation over the Himalayas by using TRMM/PR and a dense network of rain gauges

摘要

The Precipitation Radar (PR) data acquired by the Tropical Rainfall Measuring Mission (TRMM) over its 10 years of observation can be used to show the monthly rainfall patterns over the Himalayas. To validate and adjust these patterns, we used a dense network of rain gauges to measure daily precipitation over Nepal, Bangladesh, Bhutan, Pakistan, India, Myanmar, and China. We then compared TRMM/PR and rain gauge data in 0.05-degree grid cells (an approximately 5.5-km mesh). Compared to the rain gauge observations, PR systematically underestimated precipitation by 28% to 38% in summer (July-September). Monthly PR climatology was adjusted based on the monthly regressions between the 2 sets of data, and depicted.