Consistency Assessment and Uncertainty Analysis of Spatial-temporal Characteristics of Evaporation Data in the Greater Mekong Subregion

Abstract To optimize the use of evaporation products in hydro-meteorological applications across the Greater Mekong Subregion (GMS), it is crucial to evaluate the consistency of datasets and characterize their uncertainties. This study employs the Comparison Map Profile (CMP) and Three Corner Hat (TCH) methods to assess the consistency and relative uncertainty of four widely available evaporation datasets—ERA5-Land, FLUXCOM, GLDAS, and GLEAM—from 1980 to 2013. The consistency analysis indicates that the annual average evaporation rates across the four datasets range from 809.47 to 920.66 mm/yr. However, the datasets exhibit limited consistency in terms of evaporation variability. While FLUXCOM shows neither significant variability nor trends, the other datasets consistently reveal significant upward trends. The uncertainty assessment highlights that among all datasets, ERA5-Land demonstrates the highest relative uncertainty, whereas GLEAM consistently performs better, with the lowest relative uncertainty across the entire GMS region and all land cover types. Overall, based on the CMP consistency evaluation and TCH uncertainty assessment, GLEAM emerges as the most consistent dataset with the lowest relative uncertainty in the GMS. This establishes GLEAM as a valuable reference for future evaporation research and hydro-meteorological applications in the region.