Remote Sensing Analysis of the Impact of Extreme Drought on the Wetland Landscape of Nansi Lake
In the background of intensifying climate change,characterization of wetland responses to drought is of great significance.Taking the extreme drought event that occurred in the Nansi lake in 2002 as an example,based on monthly Landsat remote sensing data,long-term meteorological data,and Palmer Drought Severity Index(PDSI)data from drought years and related control periods,the Normalized Difference Vegetation Index(NDVI),Modified Normalized Difference Water Index(MNDWI),and Fractional Vegetation Cover(FVC)and the landscape patterns before and after drought were analyzed,including the Number of Patches(NP)and Patch Density(PD).The results indicated that:1)the significant decrease in precipitation during the dry year and the abnormally high temperature in the spring were the main causes for this drought event;2)in the dry year,the water area of Nansi lake had significantly decreased,and the lake dried up in October;3)the characteristics of wetland vegetation were closely related to the degree of drought(P＜0.05).With increased drought,the vegetation area,NDVI and FVC began to decrease after reaching their maximum in August;4)the landscape characteristics of wetlands show significant changes between normal and dry years.In the drought year,water area decreased significantly.The water area remained low,with an increase of 912 in NP and 15.47 in PD.The water landscape tends to be fragmented.The vegetation area significantly increased,with a fragmentation reduction.This study provides a scientific guidance for the climate adaptation management of lake wetlands.
万方数据
维普
