Accurately estimating global land evapotranspiration (ET) is crucial for a better understanding of the Earth's energy and water cycle. Although there are many existing global evapotranspiration products, recent studies have shown that there is still significant uncertainty in estimating evapotranspiration. In addition, with the increasing trend of extreme climate disasters such as droughts and heat waves, accurately estimating evapotranspiration under such extreme conditions remains a challenge. To overcome these challenges, we developed a global terrestrial evapotranspiration product using a 3-hour and 0.25 ° GLDAS dataset (i.e. net radiation, surface temperature, and air temperature) and a three temperature model (3T) (excluding resistance and parameter calibration). The results indicate that the evapotranspiration product obtained by the 3T model is highly consistent with the observed values of global conductivity towers and the water balance at the watershed scale. In addition, the global terrestrial evapotranspiration products based on 3T are comparable to other commonly used evapotranspiration products (i.e. MOD16, P-LSH, PML, GLEAM, GLDAS, and Fluxcom), but under extreme weather conditions, the 3T model performs better than GLDAS in cultivated land, with a root mean square error reduction of 9.0-20%. The proposed evapotranspiration product can provide periodic and large-scale information support for water cycle related research.
The evapotranspiration products cover the period from 2001 to 2020 and will be provided on a daily and monthly scale, with a data format of. nc4. The file name for daily data is "3T_S_T_YYYY-MM", and the file name for monthly data is "3T_S_T_YYYY". YYYY "refers to the year, and" MM "refers to the month. For ocean areas and pixels without data, the numerical number (DN) is filled with -9999. To obtain the actual evapotranspiration value, DN should be multiplied by a scaling factor of 0.01.
The Rns, Rnl, Ta, and LST datasets are from GLDAS（ https://ldas.gsfc.nasa.gov/gldas/ The spatiotemporal scales are 0.25 degrees and 3 hours, respectively (GLDAS-NAH025_3H2.1).
The monthly NDVI dataset with a spatial resolution of 0.05 degrees is from MOD13C2 (version 6).
Model calculation.
The resolution of this product is daily resolution and 0.25 degree resolution. In addition to cross validation with six commonly used global evapotranspiration products, a comprehensive evaluation of the product was conducted through direct assessment with FLUXNET EC tower data (daily and monthly scales) and watershed evapotranspiration data based on water balance (annual scale). The estimated evapotranspiration based on 3T mode is basically consistent with the above observation results.
This work is licensed under
CC BY 4.0 (Creative Commons Attribution 4.0 International License).
https://cstr.cn/31253.11.sciencedb.o00014.00001
10.57760/sciencedb.o00014.00001
