Seasonal Dependence of Evaporation Characteristics over the North Atlantic and Reliability Assessment of Multiple Datasets

Based on four datasets (ERA5, JRA-55, MERRA-2, and OAFlux) and the evaporation decomposition method, this study examines the principal spatiotemporal characteristics of North Atlantic evaporation during the cold season (December–May) and warm season (June–November) from 1980 to 2015. The results indicate that during the cold season, all four datasets consistently exhibit a meridional triple pattern, driven primarily by the wind speed term (U*) and the stability term (S*). All datasets reveal a synchronous interdecadal shift around the late 1990s, underscoring the high reliability of cold season evaporation features. In contrast, the dominant evaporation modes during the warm season diverge significantly across datasets. ERA5 and JRA-55 display a dominant zonal triple pattern, whereas this pattern emerges only as a secondary mode in MERRA-2 and OAFlux, with notable discrepancies in both spatial structure and temporal evolution. Warm season patterns are mainly controlled by the relative humidity term (RH*), and the associated uncertainties can be attributed to differences in how the various datasets characterize RH* under global warming. This study demonstrates that the cold season evaporation characteristics over the North Atlantic are highly credible, offering a robust foundation for mechanistic studies. Conversely, warm season results exhibit sensitivity to dataset selection, necessitating rigorous uncertainty assessment in future studies. Our findings provide a scientific basis for data selection and seasonal differential analysis in related research.