摘要
为探究不同植被指数计算的温度植被干旱指数(TVDI)用于东北春玉米干旱监测时受发育进程及农田环境影响的监测精度,选取干旱监测敏感性强、精度高的TVDI对东北春玉米生长季进行监测,揭示2018年东北春玉米生育期内干旱时空格局及其变化规律.基于重建的归一化植被指数(NDVI)、增强型植被指数(EVI)分别与经数字高程模型(DEM)矫正后的地表温度(LST)构建的2种植被指数LST-VI特征空间,计算2种温度植被干旱指数(TVDI-N、TVDI-E);利用特征空间拟合方程决定系数差异,确定TVDI-N、TVDI-E对干旱敏感的最佳监测时期及敏感性转换期;利用地面调查数据分析TVDI-N、TVDI-E受春玉米发育阶段、土壤质地、海拔高度、坡度等农田环境影响下的干旱监测精度.结果表明,春玉米生长前期,TVDI-N干边拟合方程决定系数持续高于TVDI-E,最大差值为0.44,最小差值为0.10,平均差值为0.23,TVDI-N和TVDI-E监测干旱等级与实测干旱等级的判对率均达到100.0%,TVDI-N监测干旱等级与实测干旱等级一致性高于TVDI-E 33.3个百分点,该阶段TVDI-N干旱监测敏感性强、精度高;春玉米生长中期,虽无明显出现一种特征空间干边拟合方程决定系数持续高于或持续低于另一种特征空间干边拟合方程决定系数情况,TVDI-N监测干旱等级与实测干旱等级的判对率低于TVDI-E 12.5个百分点,一致性检验结果则与TVDI-E相同,该阶段虽为两者敏感性转换时期,但TVDI-E监测精度更高;春玉米生长后期,TVDI-N干边拟合方程决定系数持续低于TVDI-E,最大差值为0.29,最小差值为0.13,平均差值为0.18,TVDI-E监测干旱等级与实测干旱等级判对率和一致性分别高于TVDI-N 8.7个百分点和39.2个百分点,该阶段TVDI-E干旱监测敏感性强、精度高.利用春玉米各发育阶段监测精度高的TVDI对2018年春玉米生长季干旱进行监测,得到研究区2018年2次严重干旱事件的发生、发展和减弱过程以及春玉米各发育阶段受干旱的影响情况.且春玉米生长前期干旱监测判对率达到100.0%,一致性达到83.3%;春玉米生长中后期干旱监测判对率达到82.6%,一致性达到78.3%.通过对TVDI-N、TVDI-E用于春玉米不同发育阶段干旱监测的敏感性和监测精度分析,得出TVDI-N适用于春玉米生长前期干旱监测,TVDI-E适用于春玉米生长中后期干旱监测,利用该结论对2018年东北春玉米生长季进行干旱监测,可以揭示干旱时空格局及春玉米受旱情况,提高监测精度.
In order to explore the difference of sensitivity and accuracy of temperature vegetation drought index(TVDI)calculated by different vegetation indices in monitoring spring maize drought affected by the development process and farmland environment,and to reveal the spatial-temporal pattern in drought and its variation during the growing period of spring maize of northeast China in 2018,TVDI with strong sensitivity and high accuracy was selected to monitor drought of spring maize in the growing season.Based on the reconstruction of normalized difference vegetation index(NDVI),enhanced vegetation index(EVI)and land surface temperature(LST)which was corrected by digital elevation model(DEM),LST-VI was constructed,and temperature vegetation drought index(TVDI-N,TVDI-E)was calculated.Besides,the best monitoring period and sensitive translating period of TVDI-N and TVDI-E to monitor drought were determined by the difference of constant-coefficient.What’s more,according to ground survey,the data monitoring accuracies of TVDI-N and TVDI-E were analyzed that affected by the development stage of spring maize,soil texture,altitude,slope and other farmland environments.The results showed that,at the early growing stage of spring maize,the TVDI-N dry-edge fitting equation constant-coefficient was consistently higher than TVDI-E,the maximum difference was 0.44 while the minimum difference was 0.10,and the average difference was 0.23.The judgment ratio of TVDI-N and TVDI-E monitoring drought grade to the measured drought grade was 100.0%.However,the consistence between the TVDI-N monitored drought grade and the measured drought grade was 33.3 perentage points higher than TVDI-E,which meant that it owned stronger monitoring sensitivity and higher monitoring accuracy in this period.In the middle stage of spring maize growth,although there was no obvious feature space that one dry-edge fitting equation constant-coefficient was consistently higher or lower than another,the judgment ratio of TVDI-N monitoring drought grade was lower than that of TVDI-E about 12.5 percentage points and the uniformity was the same as TVDI-E.Though this stage was a sensitive transition period,however,TVDI-E monitoring accuracy was higher than TVDI-N.At the later stage of spring maize growth,the TVDI-N dry-edge fitting equation constant-coefficient was consistently lower than TVDI-E,and the maximum difference was 0.29 while the minimum difference was 0.13,the average difference was 0.18.The judgment ratio and uniformity of TVDI-E monitored drought grade and measured drought grade were higher than TVDI-N 8.7 percentage points and 39.2 percentage points.That meant,TVDI-E drought monitoring sensitivity and accuracy were higher than TVDI-N in this period.Using different TVDI which had higher monitoring accuracy in each development stage of spring maize to monitor drought in the growing season of spring maize in 2018,the process of occurrence,development and reduction of drought in 2018 and the influence of drought on the development stages of spring maize in the study area were undrstood.Besides,in early stage of spring maize growth judgment ratio reached 100.0%and the uniformity reached 83.3%.The drought monitoring judgment ratio in middle and later stage of spring maize growth was also obtained.The judgment ratio reached 82.6%and the uniformity reached 78.3%.By analyzing the sensitivity and accuracy of TVDI-N and TVDI-E in drought monitoring at different developmental stages of spring maize,it came to the conclusion that TVDI-N was suitable for drought monitoring at early spring maize growth stage while TVDI-E was suitable for drought monitoring at middle and later spring maize growth stage.Based on the conclusion,a lasting drought monitoring was made in spring maize growing season of northeast China in 2018,which could reveal the spatial and temporal pattern of drought of spring maize and improve the monitoring accuracy.
作者
王一昊
武永峰
张立亭
张锦水
李崇瑞
张晓旭
WANG Yihao;WU Yongfeng;ZHANG Liting;ZHANG Jinshui;LI Chongrui;ZHANG Xiaoxu(College of Geomatics,East China University of Technology,Nanchang 330013,China;Institute of Environmental and Sustainable Development in Agriculture,Chinese Academy of Agricultural Sciences/Key Laboratory of Agricultural Environment,Ministry of Agriculture,Beijing 100081,China;Beijing Engineering Research Center for Global Land Remote Sensing Products/Faculty of Geographical Science,Beijing Normal University,Beijing 100875,China)
出处
《河南农业科学》
北大核心
2020年第3期167-180,共14页
Journal of Henan Agricultural Sciences
基金
“十三五”重点研发计划子课题(2017YFD0300402-2)。
关键词
东北地区
春玉米
农业干旱
遥感监测
决定系数
干旱时空格局
温度植被干旱指数
Northeast China
Spring maize
Agricultural drought
Remote sensing monitoring
Decision coefficient
Spatial and temporal pattern of drought
TVDI