First-Year Evaluation of GPM-Rainfall over the Netherlands: IMERG Day 1 Final Run (V03D)

The Global Precipitation Measurement (GPM) mission is the successor to the rainfall satellite mission TRMM (Tropical Rainfall Measurement Mission) which orbited Earth for 17 years. With its core observatory launched on February 27, 2014, GPM offers global precipitation estimates between 60°N to 60°S at 0.1° x 0.1° resolution every 30 min. Conversely to the TRMM era, now the Netherlands is within the coverage provided by GPM. Here we assess the first year of GPM rainfall retrievals from the half-hourly gridded product IMERG (Integrated Multi-satellitE Retrievals for GPM) Day 1 Final Run (V03D). This product is compared against gauge-adjusted radar rainfall maps over the land surface of the Netherlands at half-hourly, daily, monthly, and yearly scales. These radar rainfall maps are considered to be ground truth. The evaluation of the first year of IMERG operations is done through time series, scatter plots, empirical exceedance probabilities and various statistical indicators. In general, there is a tendency of IMERG to slightly underestimate (2%) country-wide rainfall depths. Nevertheless, the relative underestimation is small enough to propose IMERG as a reliable source of precipitation data, especially for areas where rain gauge networks or ground-based radars do not offer this type of high-resolution data and availability. The potential of GPM for rainfall estimation in a mid-latitude country is confirmed.