太湖流域下垫面改变与气候变化的响应关系

运用两种NDVI数据集(Pathfinder AVHRR和SPOT VEGETATION)和卫星遥感数据,采用3S技术,通过人机交互式目视方法解译出1979、1984、2000和2009年太湖流域的土地利用数据,结合1956-2007年太湖流域主要气象站点的气象资料,研究了太湖流域下垫面(NDVI和土地利用)变化与各主要气候因子的响应关系。结果表明:①近30 a太湖流域NDVI变化呈先增后减的趋势,空间上呈由东北向西南递增的趋势,浙江省区域植被覆盖较好,其次为苏锡常镇地区,上海植被较为稀少;②太湖流域耕地面积显著减少,城镇用地显著增加,林地与草地呈缓慢增长趋势,其中上海和苏州城市化进程速度最快,其次是无锡、常州,而杭州、嘉兴、湖州和镇江城市化进程较为缓慢;③20世纪80年代初期太湖流域出现显著的增温,并在近20 a增温幅度显著增加,平均相对湿度呈波动下降趋势,其下降速率为-1.25%/10 a,近50 a降水总量呈现小幅上升趋势,但近20 a降水量呈减少趋势,速率达到-37.31 mm/10 a,日照时数呈现下降趋势,其下降速率为-56.66 h/10 a;④与太湖流域NDVI变化响应最为显著的气候因子为气温,其次为平均相对湿度以及日照时数,降水总量与NDVI的相关性比较弱;⑤城市化进程迅速的地区相较于城市化缓慢的地区,其增温更快、相对湿度降幅更大、降水量增加更为缓慢,日照时数减少越快。

The Response Relationship between Underlying Surface Changing and Climate Change in the Taihu Basin

Based on the long-term vegetation index dataset of China-Pathfinder AVHRR NDVI(the data produced through funding from the Earth Observing System Pathfinder Program of NASA's Mission to Planet Earth in cooperation with National Oceanic and Atmospheric Administration, and were provided by EOSDIS, distributed Active Archive Center at Goddard Space Flight Center which archives, manages, and distributes this data set), long-term vegetation index dataset of China-SPOT VEGETATION NDVI(source for this dataset was VITO), the change of land use data which was analyzed by using the data of remote sensing image, including the interpretation of Multispectral Scanner(MSS) images in 1979, Thematic Mapper(TM) images in 1984, Enhanced Thematic Mapper Plus (ETM) images in 2000 and HJ-1 images in 2009, in combination with the meteorological data gathered from six weather stations in Taihu Basin, variation of vegetation in Taihu Basin and its NDVI in the period of 1956-2007, as well as their relations with major climate factors(temperature, relative humidity, precipitation, sunshine duration),were analyzed. The results show that: 1)The annual mean NDVI in Taihu Basin demonstrated a decreasing trend during the 26 years, with an increase rate of -0.02/10 a. The most significant NDVI decrease occurred in Changzhou area and Shanghai. It remarkably decreased by -0.017 to -0.049/10 a in those two areas. 2)The cultivated area shows significant reducing trend and the urban area shows significant increasing trend, and area of forest land, grassland and water area shows a slow increasing trend during the recent 30 years. 3)Because of the global warming and the increasingly rapid urbanization process, the annual mean temperature in Taihu Basin demonstrated an increasing trend during the 52 years, with a significant rising rate of 0.38 ℃/10 a, which caused the precipitation demonstrating an increasing trend during the 52 years with the increase rate at 1.09 mm/10 a and also caused the average relative humidity demonstrating a declining trend that decreased at a rate of -1.25%/10 a, and sunshine duration presented an decreasing trend, with the decrease rate at -56.66 h/10 a. 4)The analysis of the interrelationship between climate factor and NDVI by adopting the path coefficient shows that the temperature and the relative humidity are highly related with the NDVI(P<0.01). The correlation coefficient was -0.55 to -0.61 for NDVI and temperature, and 0.59 for NDVI and relative humidity. And the sunshine duration is also related with NDVI(P<0.05). The correlation coefficient was 0.49 for NDVI and the sunshine duration. However, no significant statistical relationship was found between NDVI and precipitation(P>0.05). This is because there's no remarkable increasing or decreasing trend found for this climate factors. The correlation coefficient was 0.23 for NDVI and precipitation.