选取植被健康指数(Vegetation health index,VHI)为农业干旱程度衡量指标,利用Mann-Kendall(M-K)检验法和小波分析法对河湟谷地2000—2020年农作物生长季(3—11月)干旱程度进行逐年和逐季节研究(以3—5月为春季、6—8月为夏季、9—11月...选取植被健康指数(Vegetation health index,VHI)为农业干旱程度衡量指标,利用Mann-Kendall(M-K)检验法和小波分析法对河湟谷地2000—2020年农作物生长季(3—11月)干旱程度进行逐年和逐季节研究(以3—5月为春季、6—8月为夏季、9—11月为秋季)。结果表明:(1)河湟谷地农业干旱区主要集中在大通河中游地区、湟水河干流区和黄河谷地。(2)河湟谷地农业干旱面积呈现明显的地域分异特点,由北到南农业干旱面积逐渐增大。(3)河湟谷地农业干旱面积在年际尺度上有在周期性波动中不断减小的趋势,2007—2008年是河湟谷地农业干旱面积发生突变的时间点,此后河湟谷地农业干旱面积开始急剧减少;春季是河湟谷地受农业干旱影响最严重的季节。研究结果对掌握河湟谷地农业干旱空间分布及变化趋势、促进青海省农业健康发展具有重要意义。展开更多
河湟谷地是青海省最重要农业区和粮食生产基地,分析河湟谷地的农业干旱演变趋势,对于保障青海省农业健康发展有着十分重要的意义。本数据集是在MOD09GA数据(地表反射率)和MOD11A1产品(LST)的基础上,利用植被健康指数(Vegetation Health ...河湟谷地是青海省最重要农业区和粮食生产基地,分析河湟谷地的农业干旱演变趋势,对于保障青海省农业健康发展有着十分重要的意义。本数据集是在MOD09GA数据(地表反射率)和MOD11A1产品(LST)的基础上,利用植被健康指数(Vegetation Health Index,VHI)计算得到,植被健康指数是耦合植被归一化指数(NDVI)和地表温度(LST)两者的相互关系来反映地区农业干旱程度的参数,本数据集覆盖的地区为河湟谷地,时间序列为2000-2020年的3-11月(生长季),3-5月(春季),6-8月(夏季),9-11月(秋季),空间分辨率为1 km×1km,数据格式为.shp和.tif,由406个文件组成,数据量为20.9 MB。展开更多
The satellite-based vegetation condition index(VCI) and temperature condition index(TCI) have been used extensively for drought detection and tracking, the assessment of weather impacts on vegetation and evaluation of...The satellite-based vegetation condition index(VCI) and temperature condition index(TCI) have been used extensively for drought detection and tracking, the assessment of weather impacts on vegetation and evaluation of the health and productivity of vegetation. In this study, in order to detect and monitor the growth condition of vegetation, we have collected data on vegetation indices and land surface temperature derived from MODIS(2001-2012) and defined a vegetation health index(VHI) based on VCI and TCI for assessing vegetation health condition in the Three Gorges Area, China(TGA). The results of the study show that temporal and spatial characteristics of vegetation health condition can be detected, tracked and mapped by the VHI index. In most parts of the TGA, the vegetation health condition showed an overall increasing trend during the study period, especially in Wulong, Fengdu, Shizhu and other regions located in the midstream sections of the Three Gorges Reservoir. In addition, the four studied vegetation types all showed clear increasing trends during the study period. The increasing trend in the vegetation health condition shows a strong positive correlation with topographical slope and altitude(below 500 m). Over the seasons, this trend is strongest in autumn, followed by spring. However, the correlations between vegetation health condition and climatic factors are more frequently significant in summer and winter than in autumn and spring. The vegetation health condition has been low in 2006 and 2011. This finding is consistent with the extreme weather conditions in those two years. However, only in the summer is vegetation health condition significantly correlated with three climatic factors in most of the study area. This result implies that vegetation growth may show a lagged response to climatic factors and may also be affected by human activities, including agricultural activities, industrial activities and other economic activities.展开更多
文摘选取植被健康指数(Vegetation health index,VHI)为农业干旱程度衡量指标,利用Mann-Kendall(M-K)检验法和小波分析法对河湟谷地2000—2020年农作物生长季(3—11月)干旱程度进行逐年和逐季节研究(以3—5月为春季、6—8月为夏季、9—11月为秋季)。结果表明:(1)河湟谷地农业干旱区主要集中在大通河中游地区、湟水河干流区和黄河谷地。(2)河湟谷地农业干旱面积呈现明显的地域分异特点,由北到南农业干旱面积逐渐增大。(3)河湟谷地农业干旱面积在年际尺度上有在周期性波动中不断减小的趋势,2007—2008年是河湟谷地农业干旱面积发生突变的时间点,此后河湟谷地农业干旱面积开始急剧减少;春季是河湟谷地受农业干旱影响最严重的季节。研究结果对掌握河湟谷地农业干旱空间分布及变化趋势、促进青海省农业健康发展具有重要意义。
文摘河湟谷地是青海省最重要农业区和粮食生产基地,分析河湟谷地的农业干旱演变趋势,对于保障青海省农业健康发展有着十分重要的意义。本数据集是在MOD09GA数据(地表反射率)和MOD11A1产品(LST)的基础上,利用植被健康指数(Vegetation Health Index,VHI)计算得到,植被健康指数是耦合植被归一化指数(NDVI)和地表温度(LST)两者的相互关系来反映地区农业干旱程度的参数,本数据集覆盖的地区为河湟谷地,时间序列为2000-2020年的3-11月(生长季),3-5月(春季),6-8月(夏季),9-11月(秋季),空间分辨率为1 km×1km,数据格式为.shp和.tif,由406个文件组成,数据量为20.9 MB。
基金Natural Science Foundation Project of CQ CSTC(CSTC2011jj A00025)
文摘The satellite-based vegetation condition index(VCI) and temperature condition index(TCI) have been used extensively for drought detection and tracking, the assessment of weather impacts on vegetation and evaluation of the health and productivity of vegetation. In this study, in order to detect and monitor the growth condition of vegetation, we have collected data on vegetation indices and land surface temperature derived from MODIS(2001-2012) and defined a vegetation health index(VHI) based on VCI and TCI for assessing vegetation health condition in the Three Gorges Area, China(TGA). The results of the study show that temporal and spatial characteristics of vegetation health condition can be detected, tracked and mapped by the VHI index. In most parts of the TGA, the vegetation health condition showed an overall increasing trend during the study period, especially in Wulong, Fengdu, Shizhu and other regions located in the midstream sections of the Three Gorges Reservoir. In addition, the four studied vegetation types all showed clear increasing trends during the study period. The increasing trend in the vegetation health condition shows a strong positive correlation with topographical slope and altitude(below 500 m). Over the seasons, this trend is strongest in autumn, followed by spring. However, the correlations between vegetation health condition and climatic factors are more frequently significant in summer and winter than in autumn and spring. The vegetation health condition has been low in 2006 and 2011. This finding is consistent with the extreme weather conditions in those two years. However, only in the summer is vegetation health condition significantly correlated with three climatic factors in most of the study area. This result implies that vegetation growth may show a lagged response to climatic factors and may also be affected by human activities, including agricultural activities, industrial activities and other economic activities.
