Assessing the ability of three global reanalysis products to reproduce South American monsoon precipitation

Abstract

El sistema del monzón sudamericano (SAMS, por sus siglas en inglés) se refiere a la fuerte variabilidad estacional de la precipitación observada en América del Sur, con lluvias intensas durante el verano, mientras que el invierno es la estación más seca. El objetivo de este trabajo es explicar cómo los diferentes conjuntos de datos de precipitación de reanálisis global (NCEP-2, ERA-Interim y CFSR-1) representan los patrones de lluvia y su intensidad asociados con el SAMS en comparación con el análisis basado en medidores (CPC). Los resultados muestran que los productos de reanálisis tienen algunas dificultades para simular tanto la distribución espacial como la intensidad de la precipitación observada. Sin embargo, ERA-Interim parece correlacionarse mejor con la variabilidad observada en la precipitación durante la temporada cálida austral. La intensidad y el posicionamiento de los flujos de humedad a 850 hPa y los patrones de divergencia asociados podrían explicar las diferencias encontradas en la precipitación de tres productos de reanálisis global en la región central del SAMS. ABSTRACTThe South American monsoon system (SAMS) refers to the strong seasonal variability in precipitation observed over South America, with high precipitation amounts during the summer while winter is the driest season. The aim of this work is to understand how different global reanalysis precipitation datasets (NCEP-2, ERA-Interim and CFSR-1) represent rainfall patterns and intensity associated with SAMS in comparison to gauge-based analysis (CPC). The results show that reanalysis products have some difficulties in simulating both spatial distribution and intensity of the observed precipitation. However, ERA-Interim seems to better correlate with the observed variability in precipitation during the austral warm season. The intensity and positioning of the 850-hPa moisture fluxes and the associated divergence patterns might explain differences found in precipitation from the three global reanalysis products in the SAMS core region.

The Atmospheric Branch of the Hydrological Cycle over the Negro and Madeira River Basins in the Amazon Region

“…The unrealistic interannual drift of precipitation observed in ERA-40 over the ARB has been reduced in ERA-Interim and the annual precipitation was largely unbiased, although the seasonal amplitude of precipitation remained too small [75]. De-Almeida et al [76] assessed the ability of three global reanalysis products (NCEP-2, ERA-Interim, and CFSR-1) to reproduce South American Monsoon (SAMS) precipitation. They found that ERA-Interim provided more consistent results regarding the climatology of precipitation and 850 hPa moisture flux divergence monthly means, both averaged over the SAMS region.…”

Assessment of the RegCM4 Performance in Simulating the Surface Radiation Budget and Hydrologic Balance Variables in South America

“…This reanalysis is available from January 1979 to August 2019 and has 1.5° × 1.5° (latitude, longitude) spatial resolution, 6 h temporal frequency and 37 vertical levels (Dee et al 2011). An inter-comparison on reanalysis data made by de Almeida et al (2018), indicated that in South America the EIN15 shows a better performance in relation to the NCEP-DOE Reanalysis 2 and Climate Forecast System Reanalysis (CFSR) version 1.…”