DAILY RAINFALL DATA VALIDATION: IMERG, CHIRPS, AND GAUGES.

Daily rainfall is important information for natural disaster prevention, water balance, and water use planning, among other purposes. Rain Gauges are the conventional instrument to measure rainfall, however, it is uncommon to have long time series without gaps. This fact forces researchers to look for other data sources, such as satellites data. This study aims to validate daily rainfall estimated by CHIRPS and IMERG based on gauge measurements between the years 2000 and 2018. The chosen area of study is the Paraiba Valley and North Coast (PVNC) region, located in Sao Paulo state, Brazil. In order to analyze how well the estimations fit the real data, statistical measures (Pearson Coefficient, Mean Absolute Error and Mean Squared Error) were applied to the data. Results demonstrated a low but significant Pearson correlation; a high Mean Squared Error; a low Mean Absolute Error and a regular Index of Agreement.