安徽省植被和地表温度季节变化及空间分布特征

摘要

Anhui Province lies in the transitional area between temperate zone and subtropical zone, so the climate here is warm and moist, and the four seasons are distinct. The north of the Huaihe River possesses a half-moist monsoon climate of warm temperate zone while the south of the Huaihe River possesses a subtropical moist monsoon climate. As a result, the climate is very suitable for various kinds of crops and plants. On the other hand, many kinds of natural disasters, such as drought, flood, and cold happen frequently every year in Anhui Province, influencing agriculture, ecosystem and people living significantly.Land vegetation and surface temperature play important roles in climate change, resource and environment change, agricultural monitoring and so on, while their in-situ investigation is very limited. Fortunately, satellite remote sensing is used widely to monitor macroscopical, large-scale, dynamic continuous vegetation and surface temperature during recent years. Using MODIS data from 2001 to 2008, seasonal,monthly and spatial variability of normalized difference vegetation index (NDVI) and land surface temperature (LST) of Anhui Province are explored. Furthermore, the relationship between NDVI and LST is analyzed. Also, spatiotemporal variability of NDVI and LST in 4 cities of Anhui Province are analyzed. The results show that spatiotemporal variability of NDVI and LST in Anhui Province are obvious. Due to local climate, the differences of vegetation lead to different seasonal changes and spatial distribution characteristics of LST in Anhui. For instance, due to evergreen broadleaf forests in South Mountain area and Dabie Mountain area, both NDVI and LST seasonal variations are smaller and they are positive correlated. However, in the north and middle most areas, the deciduous broad-leaved vegetation and seasonal crops (rice,wheat, corn, soybean, rape, etc. ) have greatly enlarged the seasonal variations of NDVI and LST, and their positive correlation is less obvious. Moreover, in cities and their surrounding areas, the correlation of NDVI and LST is negative, with urban LST significantly higher than rural values, which is notable characteristics of the urban heat island. The distribution feature of LST has been proved depending on local climate and spatiotemporal variability of NDVI in Anhui Province. These results offer an important reference for the reasonable zonation of farm belt, monitoring of ecological resource environment, the valid assessment of land use and characteristics of the urban heat island in Anhui Province.%卫星遥感广泛应用于宏观、大范围、动态连续的植被和地表温度监测研究.利用2001-2008年MODIS卫星遥感资料,分析了安徽省归一化植被指数(NDVI)和地表温度(LST)的季节、月变化和空间分布特征,探讨了代表城市区域的NDVI和LST时空分布及其相关性.结果表明:安徽省NDVI和LST季节变化显著,具有典型地域特征;受当地气候影响,植被、农作物类型地域差异较大,导致LST季节变化以及空间分布不同;城市中心向郊区过渡时,植被覆盖度在不断增加,伴随着NDVI的增加,LST下降;城市LST明显高于郊区值,呈现热岛效应.研究表明当地气候和植被分布共同决定了LST的分布状况,这将为安徽省合理进行农业区划、科学监测生态环境以及有效评估土地利用与热岛效应提供重要参考依据.