CHIRPS performance assessment for the municipatilities of São Gonçalo and Niterói (RJ)

Abstract

The study assessed the performance of CHIRPS product estimates in characterizing rainfall in the municipalities of São Gonçalo and Niterói, Rio de Janeiro, compared to 14 years of observed in situ data (2005-2018). Statistical indicators, including Pearson correlation coefficient (r), determination coefficient (R²), root mean square error (RMSE, mm), and BIAS (%), were employed. The results demonstrated satisfactory performance of the CHIRPS product. In three out of five analyzed rain gauges, the correlation (r) exceeded 0.80, and the coefficient (R²) was above 0.64. In the remaining rain gauges, the correlation was slightly lower, with (r) above 0.71 and (R²) around 0.50. The BIAS indicated CHIRPS overestimation, generally below 20%, and the RMSE showed that CHIRPS estimates had smaller errors, close to 30 (mm). Overall, the annual distribution of rainfall ranged from 850 to 1550 (mm), with higher records in the Northern (N) sector of Niterói and the South/Southeast directions of São Gonçalo. In conclusion, the CHIRPS product proved effective in providing accurate estimates and characterizing the spatiotemporal variation of precipitation in the evaluated municipalities.