Abstract
Evapotranspiration (ET) is one of the most important variables in terrestrial ecosystems, linking the carbon-water-energy cycles. In this study, we first analyze the spatial patterns of annual ET changes during 1980–2010 across China using four ET products: (i) the Global Land Evaporation Amsterdam Model version 3.0a (GLEAMv3.0), (ii) the EartH2Observe ensemble (EartH2Observe-En), (iii) the Global Land Data Assimilation System version 2.0 with Noah model (GLDAS2.0-Noah), and (iv) the Modern Era Retrospective-Analysis for Research and Application-Land (MERRA-Land). The results show that the spatial distribution of annual mean ET values and long-term changes derived from these four ET products are similar. Overall, large-scale increases in ET are observed in southeastern China, while decreases in ET over the northeast. Furthermore, we apply a newly developed separation method with the Budyko framework to quantify the individual contribution of five climatic factors to ET changes, including precipitation (P), net radiation (Rn), air temperature (T), vapour pressure deficit (VPD), and wind speed (u). It is found that the dynamics of P, Rn, and VPD are all strongly correlated with ET, suggesting that they are the major climatic factors influencing ET changes. Specifically, precipitation is the dominant factor for ET in water-limited regions, while ET changes in energy-limited regions are dominated by VPD according to all ET products except the EartH2Observe-En in which Rn and VPD have comparable performance. Our study highlights the importance of VPD in ET changes across energy-limited regions of China and suggests that the role of VPD in land surface-atmosphere interactions should be considered in future studies.
| Original language | English |
|---|---|
| Article number | 126037 |
| Pages (from-to) | 1-15 |
| Number of pages | 15 |
| Journal | Journal of Hydrology |
| Volume | 595 |
| Early online date | 2 Feb 2021 |
| DOIs | |
| Publication status | Published - Apr 2021 |
Bibliographical note
Funding Information:This research was funded by National Key Research and Development Program of China (2017YFA0603701), the National Natural Science Foundation of China (41875094), the Sino-German Cooperation Group Project (GZ1447), Startup Foundation for Introducing Talent of Nanjing University of Information Science and Technology (2243141701020), and Post-graduate Research and Practice Innovation Program of Jiangsu Province (KYCX20_0932). We appreciate all the data developers and their managers, which provide enough data sources for conducting this work. The four ET global products and their forcing climatic factors are downloaded from different websites, i.e., GLEAM3.0a from https://www.gleam.eu/, EartH2Observe-En from http://www.earth2observe.eu/., GLDAS2.0-Noah from https://disc.gsfc.nasa.gov/datasets?keywords=GLDAS, and MERRA-Land from https://disc.gsfc.nasa.gov/datasets?keywords=merra-land&page=1.
Publisher Copyright:
© 2021 Elsevier B.V.
Copyright:
Copyright 2021 Elsevier B.V., All rights reserved.
Funding
This research was funded by National Key Research and Development Program of China (2017YFA0603701), the National Natural Science Foundation of China (41875094), the Sino-German Cooperation Group Project (GZ1447), Startup Foundation for Introducing Talent of Nanjing University of Information Science and Technology (2243141701020), and Post-graduate Research and Practice Innovation Program of Jiangsu Province (KYCX20_0932). We appreciate all the data developers and their managers, which provide enough data sources for conducting this work. The four ET global products and their forcing climatic factors are downloaded from different websites, i.e., GLEAM3.0a from https://www.gleam.eu/, EartH2Observe-En from http://www.earth2observe.eu/., GLDAS2.0-Noah from https://disc.gsfc.nasa.gov/datasets?keywords=GLDAS, and MERRA-Land from https://disc.gsfc.nasa.gov/datasets?keywords=merra-land&page=1.
Keywords
- Attributed method
- ET changes
- Multi-source ET products
- VPD