CR 70:39-55 (2016)  -  DOI: https://doi.org/10.3354/cr01416

ABSTRACT: The diurnal cycle of precipitation (DCP) is not the same in every region of the globe because it depends on the local dynamics and thermodynamics of each region. The main purpose of this study was to analyze the DCP simulated by the Regional Climate Model version 4 (RegCM4) nested in the HadGEM2-ES over South America in 3 time slices: historical (1998-2005), near (2020-2048), and far (2070-2098) future climates considering the austral summer and winter seasons. This work is part of the Phase I CORDEX RegCM4 hyper-Matrix (or CREMA) experiment and uses the RCP8.5 scenario for the future climate periods. The historical period is validated by comparing the simulation with the Tropical Rainfall Measuring Mission (TRMM-2A25 and TRMM-3B42 v7) and Global Satellite Mapping of Precipitation (GSMaP MVK+) datasets. The contrasts in the DCP between tropics and extratropics registered in TRMM and GSMaP are in general simulated by RegCM4. During summer, the model simulates the peak of precipitation at 18:00 UTC in the tropical and subtropical subdomains as in the satellite products. In winter, RegCM4 overestimates the precipitation in all subtropical subdomains, and the DCP is better simulated in the tropical region. Among the results for the future scenarios, in general, in summer the near future shows the DCP pattern and intensity to be similar to the present climate, while the far future indicates an increase in precipitation intensity between 03:00 and 12:00 UTC in 8 of the 12 subdomains analyzed. 

KEY WORDS: Diurnal cycle of precipitation · Satellite products · South America · Future scenarios