喀斯特山区地表反照率时空变化及其驱动因子

Spatio-temporal variations of land surface albedo and its driving factors over the Karst mountains area

为了解全球气候变暖背景下湿润喀斯特山区地表反照率的气候效应,本文以贵州省为例,利用MODIS地表反照率产品,结合植被、土地利用、地质岩性等数据,基于Theil-Sen Median斜率计算及Mann-Kendall统计检验等方法,分析贵州省近20年地表反照率的时空变化特征;利用地理探测器分析影响贵州地表反照率的主导驱动因子。结果表明:(1)贵州省2001—2020年的地表反照率均值为0.111 0,并以每年平均0.16×10^(-3)的速率在缓慢波动下降,下降区域面积占总面积的58.17%。(2)多年季节平均反照率为夏(0.118 6)>秋(0.113 7)>春(0.105 0)>冬(0.103 0),年平均增长速率为夏(0.48×10^(-3))>秋(-0.13×10^(-3))>春(-0.31×10^(-3))>冬(-0.51×10^(-3))。(3)地表反照率年内变化呈“倒U”形,表现出显著的季节性特征。(4)植被、土地利用、岩组是贵州地表反照率时空异质的主导驱动因子,各因子间对地表反照率的交互作用均为双因子增强或非线性增强。

In order to understand the climatic effects of surface albedo in humid karst mountainous areas under the background of global warming, the author takes Guizhou province as an example in this thesis. MODIS surface albedo products, combined with data on vegetation, land use, geological lithology and other data are used. The temporal and spatial variation characteristics of surface albedo in Guizhou province in the recent 20 years are analyzed based on Theil-Sen Median slope calculation and Mann-Kendall statistical test. Geographical detector is used to analyze the dominant drivering factors of surface albedo in Guizhou. The results show that:(1) The average surface albedo of Guizhou province from 2001 to 2020 is 0.111 0, and it is slowly fluctuating and decreasing at an annual average rate of 0.16×10^(-3), with the area of decreasing area accounting for 58.17% of the total area.(2) The annual average albedo is summer(0.118 6)>autumn(0.113 7)>spring(0.105 0)>winter(0.103 0), and the annual average growth rate is summer(0.48×10^(-3))>autumn(-0.13×10^(-3))>spring(-0.31×10^(-3))>winter(-0.51×10^(-3)).(3) The annual variation of the surface albedo is inverted U-shaped, showing remarkable seasonal characteristics.(4) Vegetation, land use, and lithology combination are the dominant driving factors of the spatial-temporal heterogeneity of surface albedo in Guizhou. The interaction between these factors on surface albedo is the dual-factor enhancement or nonlinear enhancement.