Abstract:
To obtain a high-quality record of actual evapotranspiration (
ETA) with which to investigate water cycle changes in the context of climate change, this study developed a method for reconstruction of
ETA based on gravity satellite observations. The proposed method used GLDAS assimilated land surface water storage data to downscale GRACE equivalent water thickness to finer spatial resolution. Then, subbasin-level monthly
ETA data for the Jinshajiang River basin were reconstructed based on the water balance during 2002—2016. Results showed that: ① The reconstructed
ETA data (
ETRecon) had high quality and compared well with three satellite-retrieval products, i.e.,
ETPLSH,
ETJung, and
ETMODIS; the strongest correlation was with the
ETPLSH product (
r=0.82) and the lowest root mean squared difference was with the
ETJung data. ② Multiyear mean
ETA in the study area was 410.8 mm/a with a gradient of increase from northwest to southeast. Temporally, it showed a significant upward trend during 2002—2016. ③ Seasonally, summer
ETA was highest and it showed an upward trend over the study period; conversely,
ETA in winter had the lowest value and it showed trivial change temporally.