Impacts of land cover and vegetation heterogeneity on the spatial variability of surface soil moisture at the regional scale
Nan
Lu, Department of Environmental Sciences, University of Toledo, Toledo, OH 43606, USA, nan.lu@utoledo.edu
(Presenting)
Ranjeet
John, Department of Environmental Sciences, University of Toledo, Toledo, OH 43606, USA, rjohn@utnet.utoledo.edu
Burkhard
Wilske, Department of Environmental Sciences, University of Toledo, Toledo, OH 43606, USA, bwilske@utnet.utoledo.edu
Jian
Ni, Max Planck Institute for Biogeochemistry Hans-Knoell-Strasse 10, D-07701 Jena, Germany, jni@bgc-jena.mpg.de
Jiquan
Chen, Department of Environmental Sciences, University of Toledo, Toledo, OH 43606, USA, jchen4@utnet.utoledo.edu
The variability of soil water is a key factor in controlling vegetation dynamics and structure especially in the areas where precipitation is limited. In this study, the growing season surface soil moisture (Ms) status was assessed from land cover and vegetation heterogeneity in the semi-arid to arid areas in Inner Mongolia (IM) in northeastern China. We first generated a grid corresponding to that of the Advanced Microwave Scanning Radiometer (AMSR) surface soil moisture images over the IM region. We then calculated the Shannon diversity index of the land cover (H&rsquo) based on the MODIS- derived IGBP classification and the mean vegetation indices (NDVI, EVI and NDSVI) within each of the grid. We hypothesized that increasing land cover heterogeneity and vegetation cover would elevate Ms. We found that the H&rsquo value ranged from 0 to 1.4 in the desert biome, in which Ms had no correlation with H&rsquo. In the grassland biome, Ms-H&rsquo data pairs grouped to two clusters. No correlation between Ms and H&rsquo was found for either cluster. However, Ms was higher in the more heterogeneous groups. Ms was positively correlated with NDVI, EVI and NDSVI in both grassland and desert biomes however, NDSVI performed the best. The Ms-NDSVI slopes were relatively constant throughout the growing season. The variations of the Ms-NDVI (EVI) slopes were partly explained by the variations of air temperature (R2=0.21-0.40, p<0.03). The results demonstrate that land cover and vegetation heterogeneity could help to predict the spatial variation of surface moisture in this region.
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