拉萨河流域生长期NDVI对气象因子响应的时空动态特征  

Responses of Growing Period NDVI(G-NDVI)to Meteorological Factors Spatio-temporal Variations in Lhasa River Basin

作　　者：章阳 张润润[1] 郭明辰 王钊 ZHANG Yang;ZHANG Run-run;GUO Ming-chen;WANG Zhao(College of Hydrology and Water Resources,Hohai University,Nanjing 210098,China)

机构地区：[1]河海大学水文水资源学院,江苏南京210098

出　　处：《水电能源科学》2023年第8期5-9,共5页Water Resources and Power

基　　金：中央高校基本科研业务费专项资金资助(B220202035);第二次青藏高原综合科学考察研究资助(2019QZKK0207-02)。

摘　　要：拉萨河流域是青藏高原典型干旱半干旱流域,生态系统极为脆弱,研究植被指数(NDVI)对气象要素变化响应滞时的时空动态,对于探讨气候变化背景下青藏高原植被对气象因子变化的适应性具有重要意义。基于拉萨河流域1982~2017年逐月NDVI、降水量(P)、平均气温(T)数据,利用Pettitt突变及Mann-Kendall趋势检验,解析生长期NDVI及各气象因子的时空动态,并基于Pearson相关分析,识别生长期NDVI对不同气象因子响应滞时,解析气象因子对NDVI时空变化的影响。结果表明,流域尺度NDVI在1997年发生显著突变,且存在由增向减的趋势转变,流域气候由突变前的“冷湿化”向突变后的“暖干化”转变,同时其对植被生长的作用由促进转为抑制;流域内存在两条明显的NDVI对气象因子响应的滞时变化带,即流域西部多年冻土区NDVI由突变前对气象因子无响应转为突变后对P、T响应,流域南部低海拔地区NDVI对P在突变后的响应滞时较突变前延长1个月,且对T由突变前无响应转为突变后的快速响应,流域西部永久冻土区NDVI对P的响应滞时长于流域南部季节冻土区;突变后NDVI对气象因子的响应面积较突变前均有所增加,气象因子对拉萨河流域植被生长的影响作用增强。The Lhasa River Basin is a typical arid and semi-arid basin in the Qinghai-Tibet Plateau,where the ecosystem is extremely fragile.It is of great significance to study the spatio-temporal variation of vegetation index(NDVI)in response to the changes of meteorological factors,and to explore the adaptability of vegetation on the Qinghai-Tibet Plateau to the meteorological factors under the background of climate change.Based on the monthly NDVI,precipitation(P),and average temperature(T)time series dataset in the Lhasa River Basin from 1982 to 2017,using Pettitt,Mann-Kendall trend test and Pearson correlation analysis,this paper analyzed the spatio-temporal variation characteristics of growing period NDVI(G-NDVI)and meteorological factors,and identified responses patterns of G-NDVI to climate factors.The results show that the G-NDVI changed abruptly in 1997,and there was a trend shift from increasing to decreasing.The climate of the watershed changed from“wetting-colding”before the abrupt point to“drying-warming”after the abrupt point,and its effect on vegetation growth changed from promoting to inhibiting.There are two zones in the watershed where the responses patterns of G-NDVI to meteorological factors changed before and after the abrupt point.In the western permafrost areas,G-NDVI shows significant correlation with P and T in the second phase after 1997,i.e.,emerging the“responding”function on meteorological factors variation.In the southern seasonal frozen zone,after the abrupt point,time lags of G-NDVI to P were elongated,and meanwhile the“responding”of G-NDVI to T has been triggered.The latency of NDVI response to P in the western permafrost region is longer than that in the southern seasonal frozen zone.In the second phase after 1997,the response area of NDVI to meteorological factors increased compared with that before the abrupt point,and the effect of meteorological factors on vegetation growth in the Lhasa River basin was enhanced.

关 键 词：植被指数(NDVI) 气候变化 响应滞时 时空动态 拉萨河流域 

分 类 号：TV11[水利工程—水文学及水资源] Q948[生物学—植物学]