Spatiotemporal Pattern of Soil Respiration of Terrestrial Ecosystems in China: The Development of a Geostatistical Model and Its Simulation

摘要

Quantification of the spatiotemporal pattern of soil respiration (R_s at the regional scale can provide a theoretical basis and fundamental data for accurate evaluation of the global carbon budget This study summarizes the R_s data measured in China from 1995 to 2004. Based on the data, a new region-scale geostatistical model of soil respiration (GSMSR) was developed by modifying a global scale statistical model. The GSMSR model, which is driven by monthly air temperature, monthly precipitation, and soil organic carbon (SOC) density, can capture 64% of the spatiotemporal variability of soil R_s. We evaluated the spatiotemporal pattern of R_s in China using the GSMSR model. The estimated results demonstrate that the annual R_s in China ranged from 3.77 to 4.00 Pg C yr~(-1) between 1995 and 2004, with an average value of 3.84 ± 0.07 Pg C yr~(-1), contributing 3.92%-4.87% to the global soil CO_2 emission. Annual R_s rate of evergreen broadleaved forest ecosystem was 698 ± 11 g C m~(-2) yr~(-1), significantly higher than that of grassland (439 ± 7 g C m~(-2)yr~(-1) and cropland (555 ± 12 g C m~(-2)yr~(-1). The contributions of grassland, cropland, and foresrland ecosystems to the total R_s in China were 48.38 ± 0.35%, 22.19 ± 0.18%, and 20.84 ± 0.13%, respectively.