中国城市植被物候变化及其对地表温度的响应  

Spatiotemporal variations in vegetation phenology across Chinese major cities and its response to surface temperature

作　　者：缪丽娟 余志巍 何昱 张宇阳 MIAO Lijuan;YU Zhiwei;HE Yu;ZHANG Yuyang(School of Geographical Sciences,Nanjing University of Information Science&Technology,Nanjing 210044,China)

机构地区：[1]南京信息工程大学地理科学学院,南京210044

出　　处：《生态学报》2024年第6期2479-2494,共16页Acta Ecologica Sinica

基　　金：国家自然科学基金青年项目(42101295);江苏省科技计划项目(BK20210657);江苏省高校面上项目(21KJB170003)。

摘　　要：量化植被物候与城市化进程之间的关系对探索人类活动对城市生态系统的影响至关重要。以中国35个城市及周边区域为研究对象,基于中分辨率成像光谱仪(Moderate-resolution Imaging Spectroradiometer,MODIS)提供的归一化植被指数(Normalized Difference Vegetation Index,NDVI),采用Savitzky-Golay滤波和动态阈值法提取2000—2020年研究区植被返青期(Start of Growing Season,SOS)和枯黄期(End of Growing Season,EOS)。并分析不同城市规模、不同距离城市的植被物候变化对陆地地表温度(Land Surface Temperature,LST)与不透水面(Impervious Surface Area,ISA)的响应差异。研究发现:(1)2000—2020年,中国城市城区植被SOS和EOS分别以0.17d/a和0.15d/a的速率推迟。根据城市规模的不同,大城市和中等城市物候期呈推迟趋势,而超大城市、特大城市和小城市呈提前趋势。51%的城市植被SOS提前,主要分布在中国华北、西北及南部地区,其他地区城市植被SOS推迟(49%),80%的城市植被EOS推迟。空间上看,东部和南部平原地区城市植被SOS比西北部地区早(早于第91天),而EOS则比较晚(晚于第314天),而西部和北部城市植被SOS(晚于第91天)和EOS(早于第314天)呈相反态势;(2)距离城区越近,63%的城市表现为植被SOS提前(0.6—4.3 d/km),60%的城市表现为植被EOS推迟(0.2—1.9 d/km);(3)所有城市春季LST均呈现增长趋势,春季ΔLST每增长1℃,SOS提前6.8 d。秋季ΔLST每增长1℃,EOS推迟1.5 d。城市植被SOS与ISA占比显著负相关,ISA占比增长1%,植被SOS提前0.253 d,植被EOS与ISA占比显著正相关,ISA占比每增长1%,植被EOS推迟0.106 d。此外,不同人口规模的城市植被物候对LST和ISA响应存在差异,大城市和超大城市植被物候对LST和ISA占比的响应比其他城市更为敏感,表明特大城市和大城市在城郊梯度上植被物候期对LST与ISA占比响应更为明显。Quantifying the relationship between vegetation phenology and urbanization level is crucial for exploring the impact of human activities on urban ecosystems.Here,we focused on the vegetation phenology of China's 35 typical cities and their surrounding areas.Based on the Normalized Difference Vegetation Index(NDVI)provided by the Moderateresolution Imaging Spectroradiometer(MODIS),the Start of Growing Season(SOS),and the End of Growing Season(EOS)were extracted from the study area from 2000 to 2020 by Savitzky-Golay filter and dynamic thresholding method.The spatiotemporal variations of vegetation phenology in China's cities were analyzed in their urban-rural gradients,and the responses of phenology to Land Surface Temperature(LST)and Impervious Surface Area(ISA)in cities with different population sizes were compared as well.Results found that:(1)between 2000 and 2020,the SOS and EOS of urban vegetation generally exhibited a delaying trend with rates of 0.17 d/a and 0.15 d/a,while the SOS of megacities,megapolis,and small cities advanced particularly.The SOS of most southern cities and some cities in North China showed an advanced trend,and over 80% of the cities'EOS delayed.Overall,the SOS in the eastern and southern plains appeared earlier(average at DOY 91),while EOS appeared later(average at DOY 314),and SOS and EOS in the western and northern urban regions expressed an opposite trend.(2)In 63% of the analyzed cities,SOS advanced as the distance from the urban area shortened(0.6—4.3 d/km),while in 60%of these cities,EOS delayed(0.2—1.9 d/km)as the distance to the urban area decreased.(3)The spring LST of all cities presented a consistent increasing trend.For every 1℃ increase of ΔLST in spring,the SOS advanced 6.8 days.For every 1℃increase in autumn ΔLST,EOS delayed 1.5 days.There was a significantly negative correlation between urban vegetation SOS and ISA proportion,with a 1%increase in ISA proportion causing a 0.253-day advance in SOS.Additionally,there was a significantly positive correlation bet

关 键 词：MODIS NDVI 物候变化 地表温度 不透水面 城市化 中国城市 

分 类 号：Q948.1[生物学—植物学]