基于Google Earth Engine的河南省1982—2018年植被干旱研究

The Study of Vegetation Drought Health in Henan Province from 1982 to 2018 Based on Google Earth Engine

【目的】研究河南省长时序植被干旱特征。【方法】利用遥感数据并结合植被健康指数对河南省1982—2018年植被健康状态、植被健康变化趋势以及植被生长活动进行探索研究;同时基于像元尺度利用经验正交函数(Empirical orthogonal function,EOF)时空模型分析河南省四个季节的主要干旱空间分布特征。【结果】(1)从1982年至2018年,河南省在春季、夏季、冬季植被健康状态逐渐转好,干旱发生年份逐渐减少;夏季旱情在豫东、豫西、豫南和豫北四个地区以轻度干旱为主,且豫南地区旱情严重,豫东地区旱情较轻。(2)郑州市、焦作市、开封市等河南省中部、东部城市中心区对植被生长的抑制力较高,西部、东南部部分地区有助于植被生长;尽管河南省植被健康整体呈现转好趋势,但64.18%的地区植被生长存在抑制。(3)四个季节的EOF时空分析模型的第一模态方差贡献率超过95%,表明第一模态空间分布特征非常具有代表性;且在春夏季空间分布特征逐渐增强。【结论】河南省植被干旱频率逐渐减少,植被健康状态逐渐转好;城市中心区发展应该注意植被覆盖改善。

【Objective】The characteristics of long time series Vegetation Drought in Henan Province were studied.【Method】Using remote sensing data and vegetation health index,the vegetation health trends,vegetation health status and vegetation activities in Henan Province from 1982 to 2018 were studied.At the same time,the spatial distribution characteristics of main droughts in four seasons in Henan Province were analyzed by using empirical orthogonal function(EOF)spatial-temporal model based on pixel scale.【Result】(1)From 1982 to 2018,the health status of vegetation is increasing in spring,summer,winter in Henan Province,and the year of drought is decreasing.The summer drought is a mainly moderate drought in the four regions of Henan,which are western Henan,southern Henan,northern Henan,and eastern Henan,and the drought of southern Henan is serious,but it is relatively light in the eastern Henan.(2)Zhengzhou,Jiaozuo,Kaifeng and the center of other eastern cities have a big inhibition of vegetation in Henan Province,but the vegetation will grow well in the west and southeast of Henan Province.Although the overall trend of vegetation health is good in Henan Province,64.18%of the areas will Inhibit the growth of vegetation.(3)The contribution rate is over 95%on the first modal variance of the EOF space-time analysis model in four-season,which implying that the drought spatial distribution characteristics are very significant;and they are gradually enhanced in spring.【Conclusion】The frequency of vegetation drought is gradually decreasing in Henan Province,and the health status of vegetation is gradually improving in Henan Province.The development of the urban central area should pay attention to the improvement of vegetation coverage.