From TRMM to GPM: verifying the continuity of satellite-derived rainfall through comparison with Philippine synoptic measurements

After the decommission of TRMM, GPM continues to provide a global rainfall estimate on a higher spatial and temporal resolution. The continuity of the gridded satellite rainfall product is then verified at 0.25◦ spatial resolution. GPM products were upscaled from 0.1◦ to 0.25◦ resolution. The half- hourly and three-hourly satellite products were then aggregated to daily measurements. Afterwhich, the TRMM and GPM datasets were compared with daily and monthly synoptic rainfall measurements for the period 2014 to 2017. It was found out that the TRMM near-realtime product tend to underestimate daily rainfall over the country. Moreover, the post-realtime daily and monthly rainfall of GPM and TRMM agrees well with each other. It was also found out that these satellite products are strongly correlated to individual synoptic measurements with scattered varying deviations and errors across the Philippines.