Analysis of the variability of canopy resistance over a desert steppe site in Inner Mongolia, China

This study analyzed the variability of canopy resistance and associated driving environmental factors over a desert steppe site in Inner Mongolia, China, through the use of eddy-flux and meteorological data collected from 2008 to 2010. Distinct seasonal and interannual variabilities in canopy resistance were identified within those three years, and these variabilities were controlled primarily by precipitation.

Strong interannual variability was found in vapor pressure deficit (VPD), similar to that of air temperature. Based on the principal component regression method, the analysis of the relative contribution of five major environmental factors [soil-water content (SWC), leaf-area index (LAI), photosynthetically active radiation (K p), VPD, and air temperature] to canopy resistance showed that the canopy-resistance variation was most responsive to SWC (with > 35% contribution), followed by LAI, especially for water-stressed soil conditions (> 20% influence), and VPD (consistently with an influence of approximately 20%).