中国陆域干旱演变预估及其生态水文效应  

Projection of terrestrial drought evolution and its eco-hydrological effects in China

作　　者：杨远航 尹家波[1] 郭生练[1] 顾磊 何绍坤 王俊 Yuanhang Yang;Jiabo Yin;Shenglian Guo;Lei Gu;Shaokun He;Jun Wang(State Key Laboratory of Water Resources and Hydropower Engineering Science,Wuhan University,Wuhan 430072,China;School of Civil and Hydraulic Engineering,Huazhong University of Science and Technology,Wuhan 430074,China;School of Environmental Science and Engineering,Southern University of Science and Technology,Shenzhen 518055,China)

机构地区：[1]武汉大学,水资源与水电工程科学国家重点实验室,武汉430072 [2]华中科技大学土木与水利工程学院,武汉430074 [3]南方科技大学环境科学与工程学院,深圳518055

出　　处：《科学通报》2023年第7期817-829,共13页Chinese Science Bulletin

基　　金：国家自然科学基金(52009091,52209020);中央高校基本科研业务费专项资金(2042022kf1221,2021XXJS077)资助。

摘　　要：全球变暖改变了大气圈、水圈、陆地圈与生物圈的水文生物地球化学循环过程,对降水、大气湿度、陆地水储量等气象水文要素及生态系统生产力产生显著影响.现有研究较少采用陆地水储量预估未来旱情,也未能量化水热通量和生态系统碳收支对干旱的响应机制.本文首先基于GRACE/GRACE-FO重力卫星识别中国陆域干湿状况,采用大气再分析、机器学习重构和通量观测等多源数据评估对流有效位能、水汽辐合通量、生态系统总初级生产力等水-热-碳因子对干旱事件的反馈效应;然后基于ISIMIP2b框架下全球气候模式集合,考虑3种代表性浓度路径,结合动态植被模型、全球水文模型和陆面模式,预估未来陆地水储量及旱情演变特征;最后,探讨气候变化下干旱对生态系统生产力的影响,并量化干旱预估各环节的不确定性.研究发现,陆-气耦合作用与旱情演变具有复杂的互馈效应,21世纪末中国干旱历时和烈度可能大幅度增长;旱情加重影响了中国大多数陆域的生态系统净生产力,未来生态系统碳汇对干旱的调控功能减弱,且较高碳排放情景下植被受干旱胁迫影响造成的固碳下降现象更加严峻.Global warming has changed the water-energy budget and biogeochemical cycle in the Earth’s system,and has posed significant impacts on meteorological and hydrological variables such as precipitation,atmospheric humidity and terrestrial water storage(TWS),as well as ecosystem productivity.As drought is one of the most damaging weather-related hazards that challenging the social development and ecosystem heath,it is important to understand its characteristic under climate change.Recently,numerous studies have projected future droughts based on the TWS,but failed to investigate the physical mechanisms behind responses of water-heat fluxes and ecosystem carbon budget to drought events.In this study,the pattern of drought evolution and its eco-hydrological effects in China are systematically investigated from the perspective of physical processes by taking the TWS and atmospheric dynamics into consideration.Based on GRACE/GRACE-FO and Global Land Data Assimilation System(GLDAS)data from 2002 to 2020,the dry/wet land conditions are identified.Then,the complicated responses of humidity and energy factors(e.g.,relative humidity,moisture flux convergence,convective available potential energy,and convective inhibition)to drought events are identified by using observations,ERA5 reanalysis and 20th century reanalysis dataset.Meanwhile,machine learning reconstruction dataset and in situ eddy covariance flux towers data are employed to analyze the anomalies of carbon flux under dry and wet conditions in China.Subsequently,future TWS and drought conditions are projected by using a large set of Global Climate Model(GCM)under three representative concentration pathways(RCP2.6,RCP6.0,and RCP8.5),and impacts of future droughts on ecosystem carbon budget are also explored.The drought conditions are quantified by frequency,duration and severity,which are identified by using the run theory.Finally,the analysis of variance method is used to quantify the uncertainty components sourced from GCM,RCP and terrestrial hydrological models(i

关 键 词：气候变化 GRACE 干旱 碳收支 生态系统 

分 类 号：P426.616[天文地球—大气科学及气象学] P333[天文地球—水文科学]