成都信息工程大学杨泽粟团队近日的研究揭示了中国北方水-热协同塑造蒸散-降水耦合模式。这一研究成果于2024年6月5日发表在国际顶尖学术期刊《大气科学进展》上。

据悉，中国北方是陆气相互作用的一个突出“热点”，湿度和热条件都有很大的梯度。先前的研究确定了陆气耦合与各因子单独作用之间的联系，但两者的协同效应尚不清楚。

本研究考虑了蒸散量和降水的共同变化，以评估中国北方蒸散—降水(ET-P)耦合，探讨其空间变化及其与水热因子的联系。研究结果揭示了从西北部的强正耦合到东南的弱负耦合的转变，并在春季达到顶峰。这些空间变化分别被归因于水(土壤湿度)和热(空气温度)的影响，分别解释了39%和25%的变异性。干旱指数(AI)（一种水热协同因子）是主导因素，解释了66%的ET-P耦合空间的变化。

随着AI的增加，ET-P耦合从强正转向弱负，AI约为0.7。这种转变是由AI变化下的蒸散—抬升凝结水平（LCL）耦合的变化决定的。在AI低于0.7的地区，其增加的土壤水分促进了蒸散，抑制了感热(H)，降低了LCL，导致ET-LCL负耦合。相反，AI高于0.7的地区经历了能量有限的蒸散，其中正ET-LCL耦合反映了正的H-LCL耦合或LCL对蒸散的积极影响。这一分析增加了人们对多因子地表相互作用对陆气耦合空间变化的复杂影响的理解。

附：英文原文

Title: Water-Heat Synergy Shapes Evapotranspiration-Precipitation Coupling Patterns Across Northern China

Author: Zesu Yang, qiang zhang, Yu Zhang, YUE Ping, Jian Zeng, Lixia Meng, Yulei Qi

Issue&Volume: 2024-06-05

Abstract: Northern China is a prominent "hotspot" for landatmosphere interactions, with substantial gradients in both moisture and thermal conditions. Previous studies identified a link between landatmosphere coupling and the individual roles of each factor, but the synergistic effect of the two factors remains unclear. This study considered the co-variation of evapotranspiration and precipitation to assess evapotranspirationprecipitation (ET-P) coupling across northern China, exploring its spatial variations and their linkage to water and heat factors. Our findings reveal a transition from strongly positive coupling in the northwest to weakly negative coupling in the southeast, peaking in spring. These spatial variations were attributed to water (soil moisture) and heat (air temperature), which explained 39% and 25% of the variability, respectively. The aridity index (AI), a waterheat synergy factor, was the dominant factor, explaining 66% of the spatial variation in ET-P coupling. As the AI increased, ET-P coupling shifted from strongly positive to weakly negative, with an AI around 0.7. This shift was determined by a shift in the evapotranspirationlifting condensation level (LCL) coupling under an AI change. Regions with an AI below 0.7 experienced water-limited evapotranspiration, where increased soil moisture enhanced evapotranspiration, reduced sensible heat (H), and lowered LCL, resulting in a negative ET-LCL coupling. Conversely, regions with an AI above 0.7 experienced energy-limited evapotranspiration, where the positive ET-LCL coupling reflected a positive HLCL coupling or a positive impact of LCL on evapotranspiration. This analysis advanced our understanding of the intricate influences of multi-factor surface interactions on the spatial variations of land atmosphere coupling.

DOI: 10.1007/s00376-024-3256-1

Source: http://www.iapjournals.ac.cn/aas/en/article/doi/10.1007/s00376-024-3256-1viewType=HTML