青海草地生态系统水分利用效率特征及其影响因素分析  

Characteristics of Water Use Efficiency and its Influencing Factors of GrasslandEcosystem in Qinghai Province

作　　者：苏淑兰[1,2] 姬海娟 张东 张帅旗 李晓东[1,2] 苏文将[1,2] SU Shu-lan;JI Hai-juan;ZHANG Dong;ZHANG Shuai-qi;LI Xiao-dong;SU Wen-jiang(Qinghai Institute of Meteorological Science,Xining,Qinghai Province 810001,China;Key Laboratory for Disaster Prevention and Mitigation in Qinghai Province,Xining,Qinghai Province 810001,China)

机构地区：[1]青海省气象科学研究所,青海西宁810001 [2]青海省防灾减灾重点实验室,青海西宁810001

出　　处：《草地学报》2023年第9期2814-2825,共12页Acta Agrestia Sinica

基　　金：青海省气象局重点项目(QXZ2020-09);国家自然科学基金项目(41961012)资助。

摘　　要：水分利用效率(Water use efficiency, WUE)是深入理解生态系统碳水耦合的重要指标。本研究基于卫星遥感数据及青海草地系统分类数据,分析2000—2018年青海草地生态系统WUE变化特征,探讨净初级生产力(Net primary production, NPP)、蒸散(Evapotranspiration, ET)和气候因子对WUE年际和年内的变化影响。结果显示:2000—2018年,青海草地WUE均值为0.48 g·kg^(-1),其中,62.0%的区域WUE显著减小(P<0.05)。年际尺度上,WUE受ET、降水量、风速和地表温度的影响,其中与ET呈显著负相关关系(P<0.1,R^(2)=0.45)。月尺度上,WUE受ET,NPP、水热等气象条件影响,其中WUE与ET和NPP呈极显著正相关关系(P<0.01),其相关系数R^(2)分别为0.90和0.49;月WUE与气温、降水量、地表温度、水汽压、空气相对湿度极显著正相关(P<0.01),其相关系数R^(2)均大于0.55。本研究将为青海草地生态系统碳水耦合过程及其对气候变化的响应研究提供一定的数据支撑。Water use efficiency(WUE)is an important inducator to characterize the coupling process between carbon and water cycle in terrestrial ecosystem.Based on MODIS 8-day composite net primary production data(MOD17A2),evapotranspiration heat flux product data(MOD16A2)and grassland classification data of Qinghai,the WUE changes in different grassland types from 2000—2018 were analyzed.We also stuied the impacts of ET and NPP,climatic factors on the WUE changes at annually and monthly time scales.The results showed that the average annually WUE of grassland ecosystems in the Province was 0.48 g·kg^(-1).The spatial variation trend significance test on the WUE in Qinghai Province showed that there was 62.0%grassland ecosystems had significantly reduced their WUE(P<0.05).At the annual time scale,there was a quite significant negative correlation(P<0.1,R^(2)=0.45)between WUE and Evapotranspation(ET)in the grassland ecosystem,affected mainly by ET,precipitation,wind speed and surface temperature.At the monthly time scale,WUE was affected by meteorological conditions such as ET,NPP and hydrothermal conditions,and WUE significantly positive correlated with ET and NPP(P<0.01),with the coefficients R^(2) of 0.90 and 0.49.The monthly WUE was significantly positively correlated with hydrothermal conditions,including air temperature,precipitation,surface temperature,vapor pressure,and relative humidity(P<0.01),the correlation coefficients R^(2) are all greater than 0.55.This research would provide a certain data support for the study of the coupling process between carbon and water cycle and its response to climate changes of grassland ecosystems in the Qinghai Province.

关 键 词：水分利用效率 草地生态系统 蒸散 净初级生产力 

分 类 号：S153[农业科学—土壤学]