Evapotranspiration and Its Components Partitioning Based on an Improved Hydrological Model: Historical Attributions and Future Projections

Abstract

Estimation and attribution of evapotranspiration (ET) and its components under changing environment is still a challenge but is essential for understanding the mechanisms of water and energy transfer for regional water resources management. In this study, an improved hydrological model is developed to estimate evapotranspiration and its components, i. e., evaporation (E) and transpiration (T) by integrated the advantages of hydrological modeling constrained by water balance and the water-carbon close relationships. Results show that the improved hydrological model could captures ET and its components well in the study region. During the past years, annual ET and E increase obviously about 2.40 and 1.42 mm/a, particularly in spring and summer accounting for 90%. T shows less increasement and mainly increases in spring while it decreases in summer. Precipitation is the dominant factor and contributes 74.1% and 90.0% increases of annual ET and E, while the attribution of T changes is more complex by coupling of the positive effects of precipitation, rising temperature and interactive influences, the negative effects of solar diming and elevated CO₂. In the future, ET and its components tend to increase under most of the Shared Socioeconomic Pathways (SSP) scenarios except for T decreases under the very high emissions scenario (SSP5-8.5) based on the projections. From seasonal perspective, the changes of ET and the components are mainly in spring and summer accounting for 75%, while more slight changes are found in autumn and winter. This study highlights the effectiveness of estimating ET and its components by improving hydrological models within water-carbon coupling relationships, and more complex mechanisms of transpiration changes than evapotranspiration and evaporation changes under the interactive effects of climate variability and vegetation dynamics. Besides, decision makers should pay attention to the more increases in the undesirable E than desirable T.

Keywords

evapotranspiration / ET components / attribution analysis / future projections / water resources / hydrogeology

References

[1] Abiodun O O, Guan H D, Post V E A, et al. . Comparison of MODIS and SWAT Evapotranspiration over a Complex Terrain at Different Spatial Scales. Hydrology and Earth System Sciences, 2018, 22(5): 2775-2794.

[2] Agam N, Evett S R, Tolk J A, et al. . Evaporative Loss from Irrigated Interrows in a Highly Advective Semi-Arid Agricultural Area. Advances in Water Resources, 2012, 50: 20-30.

[3] Ajjur S B, Al-Ghamdi S G. Evapotranspiration and Water Availability Response to Climate Change in the Middle East and North Africa. Climatic Change, 2021, 166(3): 28.

[4] Balugani E, Lubczynski M W, van der Tol C, et al. . Testing Three Approaches to Estimate Soil Evaporation through a Dry Soil Layer in a Semi-Arid Area. Journal of Hydrology, 2018, 567: 405-419.

[5] Cheng L, Zhang L, Wang Y P, et al. . Impacts of Elevated CO₂, Climate Change and Their Interactions on Water Budgets in Four Different Catchments in Australia. Journal of Hydrology, 2014, 519: 1350-1361.

[6] Daamen C C. Two Source Model of Surface Fluxes for Millet Fields in Niger. Agricultural and Forest Meteorology, 1997, 83(3/4): 205-230.

[7] Dai X, Wang L C, Cao Q, et al. . Assessing the Hydrological and Social Effects of Three Gorges Reservoir Using a Modified SWAT Model. Journal of Earth Science, 2025, 36(4): 1793-1807.

[8] De Pury D G G, Farquhar G D. Simple Scaling of Photosynthesis from Leaves to Canopies without the Errors of Big-Leaf Models. Plant, Cell & Environment, 1997, 20(5): 537-557.

[9] Elfarkh J, Simonneaux V, Jarlan L, et al. . Evapotranspiration Estimates in a Traditional Irrigated Area in Semi-Arid Mediterranean. Comparison of Four Remote Sensing-Based Models. Agricultural Water Management, 2022, 270: 107728.

[10] Feng X M, Fu B J, Piao S L, et al. . Revegetation in China’s Loess Plateau is Approaching Sustainable Water Resource Limits. Nature Climate Change, 2016, 6(11): 1019-1022.

[11] Fisher J B, Tu K P, Baldocchi D D. Global Estimates of the Land-Atmosphere Water Flux Based on Monthly AVHRR and ISLSCP-II Data, Validated at 16 FLUXNET Sites. Remote Sensing of Environment, 2008, 112(3): 901-919.

[12] Griffis T J. Tracing the Flow of Carbon Dioxide and Water Vapor between the Biosphere and Atmosphere: A Review of Optical Isotope Techniques and Their Application. Agricultural and Forest Meteorology, 2013, 174/175: 85-109.

[13] Hattermann F F, Vetter T, Breuer L, et al. . Sources of Uncertainty in Hydrological Climate Impact Assessment: A Cross-Scale Study. Environmental Research Letters, 2018, 13(1): 015006.

[14] Helbig M, Waddington J M, Alekseychik P, et al. . Increasing Contribution of Peatlands to Boreal Evapotranspiration in a Warming Climate. Nature Climate Change, 2020, 10(6): 555-560.

[15] Hoelscher M T, Kern M A, Wessolek G, et al. . A New Consistent Sap Flow Baseline-Correction Approach for the Stem Heat Balance Method Using Nocturnal Water Vapour Pressure Deficits and Its Application in the Measurements of Urban Climbing Plant Transpiration. Agricultural and Forest Meteorology, 2018, 248: 169-176.

[16] Hua R X, Zhang Y Y, Zhang S Y, et al. . Future Change Projections of Extreme Floods at Catchment Scale and Hydrodynamic Response of Its Downstream Lake Based on Catchment-Waterbody Relationship Simulation. Journal of Geophysical Research: Atmospheres, 2023, 128(14): e2022JD037972.

[17] Jiao L, Lu N, Fang W W, et al. . Determining the Independent Impact of Soil Water on Forest Transpiration: A Case Study of a Black Locust Plantation in the Loess Plateau, China. Journal of Hydrology, 2019, 572: 671-681.

[18] Kool D, Agam N, Lazarovitch N, et al. . A Review of Approaches for Evapotranspiration Partitioning. Agricultural and Forest Meteorology, 2014, 184: 56-70.

[19] Lascano R J, van Bavel C H M, Hatfield J L, et al. . Energy and Water Balance of a Sparse Crop: Simulated and Measured Soil and Crop Evaporation. Soil Science Society of America Journal, 1987, 51(5): 1113-1121.

[20] Li L J, Song X Y, Xia L, et al. . Modelling the Effects of Climate Change on Transpiration and Evaporation in Natural and Constructed Grasslands in the Semi-Arid Loess Plateau, China. Agriculture, Ecosystems & Environment, 2020, 302: 107077

[21] Li S J, Wang G J, Sun S L, et al. . Long-Term Changes in Evapotranspiration over China and Attribution to Climatic Drivers during 1980–2010. Journal of Hydrology, 2021, 595: 126037.

[22] Li X, Gentine P, Lin C J, et al. . A Simple and Objective Method to Partition Evapotranspiration into Transpiration and Evaporation at Eddy-Covariance Sites. Agricultural and Forest Meteorology, 2019, 265: 171-182.

[23] Liu X Y, Mo X G, Liu S X, et al. . Spatiotemporal Distribution and Influencing Factors of Impervious Surface Evaporation in the Baiyangdian Catchment from 1980 to 2020. Hydrological Processes, 2024, 38(1): e15059.

[24] Liu Z F, Yao Z J, Wang R. Simulation and Evaluation of Actual Evapotranspiration Based on Inverse Hydrological Modeling at a Basin Scale. CATENA, 2019, 180: 160-168.

[25] Lu J, Wang G J, Li S J, et al. . Projected Land Evaporation and Its Response to Vegetation Greening over China under Multiple Scenarios in the CMIP6 Models. Journal of Geophysical Research: Biogeosciences, 2021, 126(9): e2021JG006327.

[26] Ma T, Wang T H, Yang D W, et al. . Impacts of Vegetation Restoration on Water Resources and Carbon Sequestration in the Mountainous Area of Haihe River Basin, China. Science of the Total Environment, 2023, 869: 161724

[27] Martens B, Miralles D G, Lievens H, et al. . GLEAM V3: Satellite-Based Land Evaporation and Root-Zone Soil Moisture. Geoscientific Model Development, 2017, 10(5): 1903-1925.

[28] Massmann A, Gentine P, Lin C J. When Does Vapor Pressure Deficit Drive or Reduce Evapotranspiration?. Journal of Advances in Modeling Earth Systems, 2019, 11(10): 3305-3320.

[29] Michel D, Jiménez C, Miralles D G, et al. . The WACMOSET Project—Part 1: Tower-Scale Evaluation of Four Remote-Sensing-Based Evapotranspiration Algorithms. Hydrology and Earth System Sciences, 2016, 20(2): 803-822.

[30] Montaldo N, Curreli M, Corona R, et al. . Fixed and Variable Components of Evapotranspiration in a Mediterranean Wild-Olive—Grass Landscape Mosaic. Agricultural and Forest Meteorology, 2020, 280: 107769.

[31] Mu Q Z, Zhao M S, Running S W. Improvements to a MODIS Global Terrestrial Evapotranspiration Algorithm. Remote Sensing of Environment, 2011, 115(8): 1781-1800.

[32] Mushimiyimana C, Liu L L, Yang Y H, et al. . Drivers of Evapotranspiration Increase in the Baiyangdian Catchment. Chinese Journal of Eco-Agriculture, 2023, 31(4): 598-607

[33] Oki T, Kanae S. Global Hydrological Cycles and World Water Resources. Science, 2006, 313(5790): 1068-1072.

[34] Senatore A, Fuoco D, Maiolo M, et al. . Evaluating the Uncertainty of Climate Model Structure and Bias Correction on the Hydrological Impact of Projected Climate Change in a Mediterranean Catchment. Journal of Hydrology: Regional Studies, 2022, 42: 101120

[35] Shan N, Ju W M, Migliavacca M, et al. . Modeling Canopy Conductance and Transpiration from Solar-Induced Chlorophyll Fluorescence. Agricultural and Forest Meteorology, 2019, 268: 189-201.

[36] Shuttleworth W J, Wallace J S. Evaporation from Sparse Crops—An Energy Combination Theory. Quarterly Journal of the Royal Meteorological Society, 1985, 111(469): 839-855.

[37] Tausz-Posch S, Dempsey R W, Seneweera S, et al. . Does a Freely Tillering Wheat Cultivar Benefit More from Elevated CO₂ than a Restricted Tillering Cultivar in a Water-Limited Environment?. European Journal of Agronomy, 2015, 64: 21-28.

[38] Tong Y, Gao X J, Han Z Y, et al. . Bias Correction of Temperature and Precipitation over China for RCM Simulations Using the QM and QDM Methods. Climate Dynamics, 2021, 57(5): 1425-1443.

[39] Vicente-Serrano S M, Miralles D G, McDowell N, et al. . The Uncertain Role of Rising Atmospheric CO₂ on Global Plant Transpiration. Earth-Science Reviews, 2022, 230: 104055

[40] Wang H N, Lv X Z, Zhang M Y. Sensitivity and Attribution Analysis of Vegetation Changes on Evapotranspiration with the Budyko Framework in the Baiyangdian Catchment, China. Ecological Indicators, 2021, 120: 106963.

[41] Wang Y P, Leuning R. A Two-Leaf Model for Canopy Conductance, Photosynthesis and Partitioning of Available Energy I. Agricultural and Forest Meteorology, 1998, 91(1/2): 89-111.

[42] Wang Y W, Wild M. A New Look at Solar Dimming and Brightening in China. Geophysical Research Letters, 2016, 43(22): 11777-11785.

[43] Wen X F, Yang B, Sun X M, et al. . Evapotranspiration Partitioning through in-situ Oxygen Isotope Measurements in an Oasis Cropland. Agricultural and Forest Meteorology, 2016, 230/231: 89-96.

[44] Xia J, Wang G S, Tan G, et al. . Development of Distributed Time-Variant Gain Model for Nonlinear Hydrological Systems. Science in China Series D: Earth Sciences, 2005, 48(6): 713-723.

[45] Xu Z W, Zhu Z L, Liu S M, et al. . Evapotranspiration Partitioning for Multiple Ecosystems within a Dryland Watershed: Seasonal Variations and Controlling Factors. Journal of Hydrology, 2021, 598: 126483.

[46] Yang D W, Sun F B, Liu Z Y, et al. . Interpreting the Complementary Relationship in Non-Humid Environments Based on the Budyko and Penman Hypotheses. Geophysical Research Letters, 2006, 33(18): 2006GL027657.

[47] Yang L S, Feng Q, Zhu M, et al. . Variation in Actual Evapotranspiration and Its Ties to Climate Change and Vegetation Dynamics in Northwest China. Journal of Hydrology, 2022, 607: 127533.

[48] Yang P, Xu F, Xia J, et al. . Agricultural Drought Vulnerability in the Middle Reaches of Yangtze River Basin under Environmental Change. Journal of Earth Science, 2025, 36(1): 184-196.

[49] Ye L Y, Cheng L, Liu P, et al. . Management of Vegetative Land for More Water Yield under Future Climate Conditions in the Over-Utilized Water Resources Regions: a Case Study in the Xiongan New Area. Journal of Hydrology, 2021, 600: 126563.

[50] Yu L Y, Zhou S, Zhao X N, et al. . Evapotranspiration Partitioning Based on Leaf and Ecosystem Water Use Efficiency. Water Resources Research, 2022, 58(9): e2021WR030629.

[51] Yu Y H, Zhou Y Y, Xiao W H, et al. . Impacts of Climate and Vegetation on Actual Evapotranspiration in Typical Arid Mountainous Regions Using a Budyko-Based Framework. Hydrology Research, 2021, 52(1): 212-228.

[52] Yuan R Q, Chang L L, Niu G Y. Annual Variations of T/ET in a Semi-Arid Region: Implications of Plant Water Use Strategies. Journal of Hydrology, 2021, 603: 126884.

[53] Zeggaf A T, Takeuchi S, Dehghanisanij H, et al. . A Bowen Ratio Technique for Partitioning Energy Fluxes between Maize Transpiration and Soil Surface Evaporation. Agronomy Journal, 2008, 100(4): 988-996.

[54] Zeng S D, Du H, Xia J, et al. . Attributions of Evapotranspiration and Gross Primary Production Changes in Semi-Arid Region: A Case Study in the Water Source Area of the Xiongan New Area in North China. Remote Sensing, 2022, 14(5): 1187.

[55] Zeng S D, Xia J, Chen X D, et al. . Integrated Land-Surface Hydrological and Biogeochemical Processes in Simulating Water, Energy and Carbon Fluxes over Two Different Ecosystems. Journal of Hydrology, 2020, 582: 124390

[56] Zhang D, Liu X M, Zhang L, et al. . Attribution of Evapotranspiration Changes in Humid Regions of China from 1982 to 2016. Journal of Geophysical Research: Atmospheres, 2020, 125(13): e2020JD032404.

[57] Zhao L L, Xia J, Xu C Y, et al. . Evapotranspiration Estimation Methods in Hydrological Models. Journal of Geographical Sciences, 2013, 23(2): 359-369.

[58] Zhou S, Yu B F, Zhang Y, et al. . Partitioning Evapotranspiration Based on the Concept of Underlying Water Use Efficiency. Water Resources Research, 2016, 52(2): 1160-1175.

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