摘要
精准量化气候变化对NDVI的影响趋势和确定关键驱动气象要素,对于生态脆弱区的植被管理具有重要意义.基于辽西北地区23个气象站点1998-2020年生长季气象数据和MODIS NDVI遥感影像数据,利用Theil-Sen Median斜率估计和Mann-Kendall趋势分析法,分析了 NDVI、气温、降水、日照时数和蒸散发的变化趋势.运用空间插值、相关分析、多元回归和波段运算,探讨了 NDVI与气象要素的相关性及关键气候驱动力的时空格局.结果表明:辽西北地区1998-2020年NDVI以倾向率0.03 10 a-1呈显著增加趋势(P＜0.01),但气候变化趋势不显著.1998-2008年和2009-2020年气温、蒸散发、日照时数和降水变化趋势相反.辽西北地区NDVI与气温、蒸散发和日照时数主要呈负相关而与降水呈正相关,2009-2020年NDVI与气候相关性明显弱于1998-2008年.1998-2008年日照时数和蒸散发相对重要值比例分别为54.52％和22.93％,分别是中西部和东部植被变化的主要驱动因子.2009-2020年蒸散发和气温相对重要值比例分别为38.18％和26.89％,蒸散发主要影响中部和西北部,而气温主要驱动的局域分布较分散.辽西北地区植被变化受降水影响相对较小.研究明确了区域植被变化及局域关键气候驱动要素,可为辽西北生态脆弱区修复提供科学依据.
Abstract
Accurately quantifying the influence of climate change on NDVI and determining key driving meteoro-logical factors are of great significance for vegetation management in ecologically fragile areas.Based on the meteor-ological data and MODIS NDVI remote sensing image data of 23 meteorological stations in Northwest Liaoning dur-ing the growing season from 1998 to 2020,we analyzed the change trends of NDVI,air temperature,precipitation,sunshine time and evapotranspiration using Theil-Sen Median slope estimation and Mann-Kendall trend analysis.The correlation between NDVI and meteorological elements and the spatial-temporal variations of key climate drivers were examined by using spatial interpolation,correlation analysis,multiple regression,and bandmath.The results showed that NDVI significantly increased with a rate of 0.03 10a-1 from 1998 to 2020 in Northwest Liaoning(P＜0.01),but the change of climate was not significant.The trends of the changes in air temperature,evapotranspi-ration,sunshine time,and precipitation during 1998-2008 and 2009-2020 were opposite.In Northwest Liaoning,NDVI was negatively correlated with air temperature,evapotranspiration,and sunshine time,but positively correla-ted with precipitation.The correlations between NDVI and those four climatic factors during 2009-2020 were obvi-ously weaker than that during 1998-2008.The proportion of relative importance value for sunshine time and evapo-transpiration was 54.52％and 22.93％during 1998-2008,which were the main driving factors of NDVI in central-western part and eastern part,respectively.During 2009-2020,the proportion of relative importance value for e-vapotranspiration and air temperature accounted for 38.18％and 26.89％,respectively.Evapotranspiration mainly affected the NDVI of central-northwest part,while the local distribution pattern of NDVI mainly driven by air tem-perature was relatively scattered.Precipitation had slight effects on vegetation change in Northwest Liaoning.This study clarified the regional vegetation change and the driving climate factors,which could provide scientific basis for vegetation restoration of ecologically fragile areas in Northwest Liaoning.
基金项目
中国气象局沈阳大气环境研究所联合开放基金(2021SYIAEKFMS42)
中国科学院大学生创新实践训练计划(20224002538)
国家科技期刊平台
NSTL
万方数据