| 摘 要： |
land-atmosphere coupled regional climatemodel (WRF) to investigate the land surface changes and their associated thermal andmoisture impacts across three main ecosystems over theHeilong-Amur River basin from 1982 to 2018. Firstly, satellite observations indicated an overall greening in HARB, with variations across ecosystems. The significant summer farmland greening is the most representative, with the farmlandgreenvegetationfraction(GVF) remarkably increasing by 7.78% insummer. The forest greeningmagnitude is stronger in spring (3.42%) than in summer (2.85%), while the grassland vegetation showed some local browning signals in summer. Secondly, our simulated results showed the summer farmland greening accelerated evapotranspiration (ET) by 0.161 mm/d and significantly cools the surface temperature by 0.508 degrees C averaged at the ecosystem scale, whichwas highly correlated with the satellite observations butwith lower coolingmagnitude. The forest greening brought less surface cooling in spring than summer due to the stronger albedo feedback, despite with greater increase in GVF and ET. While with the opposite process, the local grassland browning leads to consistent warming effects, which can be detected from both satellite observations and our simulation results. Finally, our results also found that rainfall increasing averagely at the ecosystem scale can't fully compensate the water emission from enhanced ET due to the surface greening, contributing to soilmoisture decline in both farmland and relative dry forests. (C) 2021 Elsevier B.V. All rights reserved. |
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