伊犁河谷植被物候变化特征及其对气候变化的响应

Characteristics of Vegetation Phenology Changes and Its Response to Climate Change in the Yili River Valley

本文基于2001—2021年MODIS NDVI数据和气象数据,利用TIMESAT软件提取伊犁河谷植被物候参数,结合Sen趋势分析、M—K检验和偏相关分析等方法,研究伊犁河谷植被物候变化特征及其对气候(气温、降水)变化的响应。结果表明:伊犁河谷植被生长季始期(Start of the growing season,SOS)、生长季末期(End of the growing season,EOS)、生长季长度(Length of growing season,LOS)主要集中在45~113 d,290~335 d,186~279 d,海拔每上升100 m,SOS约推迟1.9 d,EOS提前1 d,LOS缩短2.9 d。SOS呈提前的像元占79.91%;EOS呈推迟的像元占81.64%;LOS呈延长和缩短的像元占31.89%,26.39%。1000 m以下草原SOS最早且提前天数最多(61.5 d);1000 m以上草原EOS提前天数最多(34.8 d),阔叶林仅提前7.6 d。SOS受2,3月气温及1,2月降水影响,3月气温升高使SOS提前;EOS与8月气温正相关,与9月降水负相关。本研究为伊犁河谷的植被资源保护与生态环境可持续发展提供科学依据。

In this paper,based on MODIS NDVI data and meteorological data from 2001 to 2021,we extracted the vegetation phenology parameters of the Yili River Valley using TIMESAT software,and combined the methods of Sen trend analysis,M-K test,and bias correlation analysis to study the characteristics of the vegetation phenology changes in the Yili River Valley and its response to the changes of the climate(air temperature and precipitation).The results showed that:Start of the growing season(SOS),End of the growing season(EOS),and Length of growing season(LOS)of the vegetation in the Yili River Valley were mainly concentrated in 45~113 d,290~335 d and 186~279 d.For every 100 m of elevation rise,SOS was delayed by 1.9 d,EOS was advanced by 1 d,and LOS was shortened by 2.9 d.SOS showed 79.91%of the image elements that were advanced;EOS showed 81.64%of the image elements that were delayed;and LOS showed 31.89%and 26.39%of the image elements that were lengthened and shortened.Grassland below 1000 m of altitude has the earliest SOS and the highest number of days in advance(61.5 d);grassland above 1000 m of altitude has the highest number of days ahead(34.8 d)for EOS,and broadleaf forests have only 7.6 d ahead.SOS was influenced by February and March temperatures and January and February precipitation,with higher temperatures in March advancing SOS;EOS was positively correlated with August temperatures and negatively correlated with September precipitation.This study provides a scientific basis for the conservation of vegetation resources and the sustainable development of the ecological environment in the Yili River Valley.