This paper presents a very early evaluation and comparison of GPM Level 3 IMERGHH and TRMM3B42V7 final products from 2014/4/1 to 2015/3/31 at daily scale over whole Mekong River Basin (MRB). Daily observation data from 53 in situ rainfall gauges is obtained to do the pixel-point comparison. Two aspects (rainfall amount and occurrence) were taken to evaluate the performance of these two satellite precipitation products. The result demonstrates that: (1) both TRMM3B42 V7 and GPM 3IMERGHH have an underestimation of rainfall over MRB; (2) the performance of the two products in wet season is better than dry season; (3) generally TRMM3B42V7 can achieve a better estimation of rainfall amount than GPM 3IMERGHH during both wet season and dry season; (4) for event judge, GPM can get a better result than TRMM3B42 V7 with a higher Probability of Detection (POD) and a higher Critical Success Index (CSI); (5) TRMM3B42 V7 is more likely to miss a rainfall event while GPM is more likely to make a false alarms. This study shows that although GPM has more capacity to catch a rainfall event, it still has much room for further improvement, especially in the estimation of rainfall amount in dry season.
['Wei Wang', 'Hui Lu']
Evaluation and comparison of newest GPM and TRMM products over Mekong River Basin at daily scale