On the quality of satellite-based precipitation estimates for time series analysis at the central region of the state of São Paulo, Brazil

• Published in: Theoretical and applied climatology 2023, Vol.151 (1-2), p.467-489
• Main Authors: dos Santos, Bruno César, Sanches, Rafael Grecco, de Melo Bolleli, Talyson, de Souza, Paulo Henrique, Bourscheidt, Vandoir
• Format: Article
• Language: English
• Subjects: Analysis; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Atmospheric Sciences; Climate science; Climatology; Cruise stations; Earth and Environmental Science; Earth Sciences; Environmental hazards; Error analysis; Estimates; Gauges; Hydrologic data; Meteorological satellites; Monthly; Original Paper; Precipitation; Precipitation estimation; Precipitation variability; Quality management; Rain; Rain and rainfall; Rain gauges; Rainfall; Rainfall data; Remote sensing; Satellite communications; Satellites; Trend analysis; Waste Water Technology; Water Management; Water Pollution Control
• ISSN: 0177-798X; 1434-4483
• DOI: 10.1007/s00704-022-04287-y

With the advance of remote sensing technologies, meteorological satellites have become an alternative in the process of monitoring and measuring meteorological variables, both spatially and temporally. The present study brings some additional elements to the existent validations of satellite-based precipitation estimates from CHIRPS (Climate Hazards Group Infra-Red Precipitation with Station) all around the world, by analyzing its monthly product in the period 1981–2019 over the central region of the state of São Paulo, Brazil. There are significant variations over time in the number of rain gauges used by CHIRPS at the region, and the product quality has been evaluated under these conditions. Initially, the general relationship between satellite estimates and surface rainfall data is assessed using the linear adjustment and error analysis in both temporal and spatial perspectives, followed by a trend analysis using Laplace test. Results show an average decrease of 20% in R 2 values when gauges were not used as anchor/reference stations by CHIRPS; the same behavior is observed for the other metrics. The monthly map analysis, besides the evident impact of the use or not of the gauges as reference stations, showed a better performance of CHIRPS (in terms of R 2 ) during the dry period (April to August) than for the wet period (October to March), especially when anchor stations were not available. On the other hand, CHIRPS tends to underestimate (overestimate) low (high) rain rate events. Finally, despite the changes in product over time, monthly trends showed, in general, the same pattern of variability in rainfall over 38 years and a prevalence toward the reduction of rainfall. In summary, CHIRPS product seems a reasonable alternative for regions that lack historical rainfall information, but a careful analysis on the product diagnosis should be made when temporal analysis is conducted.