摘要
秦岭是我国自然环境的天然分界区,是我国中部重要的生态屏障,也是南水北调重要的水源涵养区。为了更好地服务于生态环境建设,选取MODIS植被指数NDVI、地表温度及地表蒸散数据产品,针对秦岭地区生态环境建设以来2001-2013年植被及水热条件发生的变化以及空间分布规律进行分析。结果表明,从区域平均情况来看,只有NDVI有显著升高的变化趋势,耕地区NDVI变化趋势大于林草区域。林草区NDVI、蒸散平均值高于耕地区,而地表温度在耕地区高于林草区。从各像元的空间分布图来看,NDVI、地表温度和蒸散的空间分布都有明显的山体脉络。NDVI随高度的增加而增大,2000m左右开始略微下降。地表温度随高度的升高呈极显著的线性下降趋势,海拔每升高100m温度下降0.51℃。蒸散随海拔高度先是增高,在海拔800~1800m变化趋于平缓,随后随海拔的升高而降低。NDVI、地表温度和蒸散都在低海拔地区变化明显。2001-2013年秦岭地区NDVI呈显著增加趋势,与陕西开展的生态环境建设工程密不可分。在全球增温的背景下,地表温度没有明显变化,与植被的调节作用有一定关系。蒸散的增加趋势与NDVI的上升引起蒸腾作用加大有关,而蒸散的减小趋势与太阳辐射的减小有关。
The Qinling Mountains is not only the natural boundary of southern and northern China,but also is a significant ecological barrier in the middle of China,and an important water source conservation area of South-to-North Water Transfer Project.In order to serve the ecological environment construction with scientific and accurate information,NDVI (normailized difference vegetation index),LST (land surface temperature)and ET (evapotranspiration)of MODIS datasets were used to analyze the spatiotemporal variation laws and change relations of vegetation cover and hydrothermal condition after developing ecological environment construction in the Qinling Mountains area (2001-2013).It was found that generally,only NDVI presented extremely significant increasing trend in volatility,and in farmland it was more significant than in forest-grassland.NDVI and ET in forest-grassland were higher than in farmland,but LST in farmland was higher than in forest-grassland.From the point of the spatial distribution,spatial variations of NDVI,LST and ET presented mountainous features.NDVI increased with the increase of altitude,began to decline slightly at about 2 000 m.LST presented extremely significant linear downward trend with altitude.In addition,LST dropped 0.51℃ as altitude increased for every 100 m.With the increase of altitude,ET started to increase below 800 m and later flattened at 800-1 800 m,and then decreased in the end.NDVI,LST and ET changed obviously in low altitude.From 2001 to 2013,the improvement of NDVI in the Qinling Mountains area was the interactive effect of implementation of a series of ecological construction projects such as closing hill for forestation and restoring farmland into forestland and grassland.Under the background of global warming,no obvious change in LST,indicating a certain correlation with the regulation function of vegetation.The increase trend of ET caused by the improvement of NDVI,and the decrease trend of ET was associated with the decrease of solar radiation.
作者
何慧娟
王钊
董金芳
王娟
HE Hui-juan;WANG Zhao;DONG Jin-fang;WANG Juan(Shaanxi Agricultural Remote Sensing and Economic Crop Meteorological Service Center,Xi an 710014,Shaanxi,China)
出处
《西北林学院学报》
CSCD
北大核心
2019年第4期179-184,191,共7页
Journal of Northwest Forestry University
基金
陕西省气象局“火车头计划”环境遥感应用创新团队项目
