1998~2016中国八大经济区植被覆盖对PM_(2.5)浓度时空分布的影响

Effect of Vegetation Coverage on the Temporal and Spatial Distribution of PM_(2.5) Concentration in China's Eight Major Economic Regions from 1998 to 2016

目前很少有PM_(2.5)污染与植被覆盖的相关性深入研究,尝试对此进行补充.基于1998~2016年的PM_(2.5)和归一化植被指数(NDVI)的栅格数据,以中国内地八大经济区为研究对象,对NDVI值进行3个等级划分(低植被覆盖区、中植被覆盖区和高植被覆盖区),并计算相应等级的PM_(2.5)污染浓度.在此基础上,从NDVI的景观尺度和类型尺度分析PM_(2.5)污染的时空特征,然后利用面板数据模型定量化NDVI景观格局指数对PM_(2.5)的影响.结果表明:①北部沿海、东部沿海、南部沿海、长江中游和东北经济区在植被覆盖相对较低的区域,PM_(2.5)污染较严重;而黄河中游、西南地区及大西北经济区则在植被覆盖相对较低的区域表现出较轻的PM_(2.5)污染;②大部分区域的PM_(2.5)随时间变化呈显著上升趋势;③PM_(2.5)与NDVI景观格局指数相关性显著(P<0.05)的区域相对较少;④景观形状指数(LSI)、斑块面积比(PLAND)、斑块数量(NP)、最大斑块占景观面积比(LPI)和聚集度指标(AI)指数对PM_(2.5)的影响都表现出明显的空间异质性.

The study researched the relationship between vegetation cover and PM_(2.5)pollution.The raster NDVI dataset from 1998 to 2016 were reclassified into low,medium,and high vegetation coverage area,and the corresponding PM_(2.5)concentration in eight economic regions in China were then calculated.On this basis,the temporal and spatial characteristics of PM_(2.5)pollution were analyzed and Pearson correlation coefficient was used to explore its correlation with NDVI landscape pattern indexes separately from landscape and class level NDVI.The preliminary results showed that:①The northern,eastern,southern coastal,middle reaches of the Yangtze River,and the northeast economic zones have relatively low vegetation coverage in areas with relatively serious PM_(2.5)pollution.However,the middle reaches of the Yellow River,the southwestern and the Northwestern Economic Zones in areas with relatively low vegetation coverage showed lighter PM_(2.5)pollution.②PM_(2.5)increased in most areas between 1998 and 2016.③A significant correlation between PM_(2.5)and NDVI landscape pattern indexes was not found for all areas.④Therefore,the impacts of the landscape shape index(LSI),percent of landscape(PLAND),number of patches(NP),largest patch index(LPI),and aggregation index(AI)on PM_(2.5)are heterogeneous.