基于地理加权回归的青藏高原季节冻土区土壤有机碳空间分布研究

Modelling soil organic carbon distribution in the seasonally frozen ground area on the Qinghai-Tibet Plateau using the geographically weighted regression

青藏高原土壤有机碳储量(soil organic carbon stocks,SOCS)对于区域生态环境演替具有重要作用,但是其空间分布数据还比较缺乏,特别是季节冻土区的数据较少。基于378个土壤剖面数据,结合与土壤有机碳(soil organic carbon,SOC)相关的地形、气候以及植被等环境因子,使用地理加权回归(geographically weighted regression,GWR)模型模拟了青藏高原季节冻土区0~30cm、0~50cm、0~100cm和0~200cm深度的SOC总量和空间分布。结果表明:青藏高原季节冻土区SOCS自东南向西北递减,表层0~200cm的SOC总量约15.37Pg;季节冻土区不同植被类型SOC从大到小依次为森林、灌丛、高寒草甸、高寒草原和高寒荒漠;各土壤类型中棕壤、黑钙土和泥炭土的SOC最大,而棕钙土、棕漠土、灰棕漠土、风沙土、石质土、盐土、冷钙土、寒漠土以及冷漠土的SOC最小。研究结果给出了青藏高原季节冻土区SOC的总量、空间分布及规律,可为相关地球模式的发展提供基础数据。

Soil organic carbon stocks(SOCS)in the Qinghai-Tibet Plateau have important implications for ecology succession,while the spatial distribution of SOC data are scarce,especially in seasonally frozen ground regions. Here,based on the multiple environmental variables and soil profile data(n=378),we evaluated the soil organic carbon(SOC)pool and spatial distribution of seasonally frozen ground which down to2 m depth on the Qinghai-Tibet Plateau using the geographically weighted regression(GWR)approach. Our results showed that SOCS exhibited a decreasing tread from south-eastern to the north-western,and the SOC pools were estimated to be15.37 Pg in the top2 m. The average SOC under different vegetation types showed a decreasing trend as follows:forest>shrub> alpine meadow> alpine grassland> alpine desert. Among all soil types,brown earths,chernozems,and peat soils had the largest SOC,while brown pedocals,brown desert soils,grey-brown desert soils,Aeolian soils,chisley soils,saline,frigid desert soils,cold desert soil,and cold desert soils had the smallest SOC. Our results provided the storage,pattern,and spatial distribution of SOC in the seasonally frozen ground area,providing a scientific basis for future studies pertain to the Earth System Models.