Evaluation of surface latent heat and sensible heat fluxes from ERA-5, GLDAS, and MODIS on different underlying surfaces in the Tibetan Plateau

Surface-latent heat(LE) and sensible heat(SH) fluxes play a pivotal role in governing hydrological, biological, geochemical, and ecological processes on the land surface in the Tibetan Plateau. However, to accurately assess and understand the spatial distribution of LE and SH fluxes across different underlying surfaces, it is crucial to verify the validity and reliability of ERA-5, GLDAS, and MODIS data against ground measurements obtained from the Flux Net micrometeorological tower network. This study analyzed the spatial patterns of LE and SH over the Tibetan Plateau using data from ERA-5, GLDAS, and MODIS. The results were compared with ground measurements from Flux Net tower observations on different underlying surfaces, and five statistical parameters(Pearson's r, LR slope, RMSE, MBE, and MAE) were used to validate the data. The results showed that:(1) MODIS LE data and ERA-5 SH data exhibited the closest agreement with ground observations, as indicated by their lowest root mean square error and mean bias area values.(2) The accuracy of ERA-5 SH was the highest in meadows and steppes, while GLDAS SH performed optimally in shrublands. Notably, MODIS LE consistently outperformed the other datasets across all vegetation types.(3) The spatial distribution of LE and SH displayed considerable heterogeneity, contingent upon the specific data sources and underlying surfaces. Notably, there was a contrasting trend between GLDAS and ERA-5, as well as MODIS, in terms of SH distribution in the shrubland. In shrublands and meadows, MODIS SH and LE exhibited more pronounced changes than ERA-5 and GLDAS. Additionally, ERA-5 SH demonstrated the opposite variation in meadow and steppe regions compared to GLDAS and MODIS.