北方地区叶面积指数变化对蒸散和产水量的影响  

Effect of leaf area index change on evapotranspiration and water yield in northern China

作　　者：柳艺博[1] 胡正华[1,2] 李琪[1] 张雪松[1] 张琪[1] LIU Yibo;HU Zhenghua;LI Qi;ZHANG Xuesong;ZHANG Qi(School of Applied Meteorology, Nanjing University of Information Science and Technology / Jiangsu Key Laboratory of Agricultural Meteorology, Nanjing 210044, China;Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Nanjing University of Information Science and Technology, Nanjing 210044, China)

机构地区：[1]南京信息工程大学应用气象学院/江苏省农业气象重点实验室,南京210044 [2]南京信息工程大学气象灾害预报预警与评估协同创新中心,南京210044

出　　处：《中国生态农业学报》2017年第8期1206-1215,共10页Chinese Journal of Eco-Agriculture

基　　金：公益性行业(气象)科研专项(重大专项)(GYHY201506001-6);国家自然科学基金项目(41401218)资助~~

摘　　要：越来越多的证据表明伴随植树造林/再造林等工程实施,我国北方地区叶面积指数(LAI)近年来变化明显。但有关植树造林等引起的LAI变化对水循环的影响仍存在争议。本研究利用卫星遥感LAI数据和生态过程模型(BEPS)评价了2000—2014年北方地区LAI变化对蒸散和产水量的影响。首先评价了北方地区LAI的变化趋势;在此基础上采用"去趋势"法去除LAI变化趋势而仅保留其年际变化;而后分别基于原始和去趋势后LAI序列驱动BEPS模拟北方地区蒸散;最后基于两种情景比较分析LAI变化对蒸散和产水量的影响。结果表明,北方地区LAI发生显著变化的地区占北方地区面积的20.2%,其中LAI显著升高和显著降低地区面积分别占18.8%和5.5%。在像元尺度上,LAI升高会促进蒸散并降低产水量,LAI降低则相反。在区域尺度上,LAI升高分别对蒸散和产水量产生了显著的正负效应;LAI变化对水循环影响取决于研究区覆盖范围和研究区内LAI升高和降低的比例。考虑到LAI升高对产水量可能产生的负效应和北方地区的缺水危机,未来植树造林活动或许应该考虑更多集中于南方地区。There has been growing evidence that leaf area index(LAI)has changed in many parts of northern China,including northeast(NER),north(NR),northwest(NWR)and Huanghuaihai(HHH)regions.Changes in LAI can alter hydrologic cycle by regulating matter and energy cycles.However,the effects of the changes in LAI,particularly for afforestation/reforestation,on the hydrologic cycle have remained controversial.Better understanding on how the changes in LAI affect evapotranspiration(ET)and water yield has implications for ecohydrology,and regional and national afforestation/reforestation policies.In this study,we used satellite-derived LAI dataset and process-based ecosystem model(Boreal Ecosystem Production Simulator,BEPS)to examine how changes in LAI affect annual ET and water yield in northern China during the period2000_2014.Firstly,LAI dataset was used to assess linear trends in LAI per pixel.Secondly,increasing and decreasing trends in LAI were removed on per-pixel basis by detrending LAI.Thirdly,we used the BEPS model along with the original and detrended LAI datasets to conduct two model simulations-one with original LAI(i.e.,with increasing and decreasing trends in LAI)and one with detrended LAI(i.e.,without trends in LAI).Finally,the two model simulations were conducted to assess the effects of increasing and decreasing LAI on terrestrial ET and water yield in northern China.Results showed significant trends in LAI for20.2%of area of northern China,with increases and decreases in area accounted for18.8%and5.5%,respectively.Annual mean LAI averaged at the regional scale significantly increased for NR(0.0014a?1,P<0.05)and NWR(0.0047a?1,P<0.001).Temporal trends in LAI were not significant for NER and HHH.Two model simulations driven by original and detrended LAI,respectively,showed that the effects of the changes in LAI on terrestrial ET and water yield varied with spatial scale.At pixel scale,an increase in LAI increased annual ET but decreased water yield or weakened increase in water yield.However,a decrease in LAI dec

关 键 词：叶面积指数 蒸散 产水量 生态过程模型 北方地区 

分 类 号：TP79[自动化与计算机技术—检测技术与自动化装置] P339[自动化与计算机技术—控制科学与工程]