Evaluation of Sixteen Gridded Precipitation Datasets over the Caribbean Region Using Gauge Observations

Abel Centella-Artola,Dimitris A Herrera,Tannecia Stephenson,Arnoldo Bezanilla-Morlot,Michael A Taylor,Milena Alpizar,Maibys Sierra-Lorenzo,Cecilia Fonseca,Isabelle Gouirand,Jayaka Campbell,Daniel Martinez-Castro,Alejandro Vichot-Llano

doi:10.3390/atmos11121334

Abstract

The existence of several gridded precipitation products (GPP) has facilitated studies related to climate change, climate modeling, as well as a better understanding of the physical processes underpinning this key variable. Due to complexities in estimating rainfall, gridded datasets exhibit different levels of accuracy across regions, even when they are developed at relatively high resolution or using sophisticated procedures. The performance of 16 GPP are evaluated over the Caribbean region, which includes the Caribbean Islands, and portions of Central South America. Monthly data for sixty weather stations are used as a reference for the period 1983–2010. The 16 GPP include six products based on station data only, two that combine ground station and satellite information, two merging station and reanalysis information, four based on reanalysis, and two using multisource information. The temporal resolution of the GPP ranged between daily and monthly and spatial resolution from 0.033° to 0.5°. The methodological approach employed combined a comparison of regional and sub-regional precipitation annual cycles, the Kling–Gupta efficiency (KGE) index, as well as several metrics derived from the standardized precipitation index (SPI). Overall, the best performances were obtained from GPCC025 and MSWEP2, likely reflecting the positive impact of the large number of station data utilized in their development. It is also demonstrated that a higher spatial resolution does not always mean better accuracy. There is a need for this kind of assessment when undertaking climate studies in regions like the Caribbean where resolution is a significant consideration. ERA5 performed best among the reanalyses analyzed and has the potential to be used to develop regionally based GPP by applying bias correction or downscaling techniques. The methodological approach employed provides a comprehensive and robust evaluation of the relative strengths and weaknesses of GPP in the Caribbean region.

Highlights

Precipitation is one of the most important climatic variables and it is included in a large number of studies of weather and climate
The gridded precipitation products (GPP)’ performance is significantly better in the western Caribbean, though substantial departures exist between observations and some GPP e.g., CPCGLOBAL and ERA5
We suggest that the use of a coarse precipitation dataset (2.5◦ ) such as GPCP [16], possibly reduces the skill of PERSIANNCDR to adequately represent precipitation features in the Caribbean

Summary

Introduction

Precipitation is one of the most important climatic variables and it is included in a large number of studies of weather and climate. The adequate representation of the spatial and temporal variations of precipitation is difficult, mainly because it is significantly affected by the availability and quality of observed data. The rain gauges are the most suitable ways to estimate precipitation [8], stations are often sparsely located, and present errors that arise from instrumental and non-instrumental problems (e.g., wind influences) which limit the quality of the observed data [9,10]. Despite the notable advances in estimating precipitation from satellite data, this option is limited by temporal sampling and algorithm errors [11]

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