珠江流域岩石风化作用消耗大气/土壤CO2量的估算

以流域的岩性、径流量和水化学分析数据为主要资料,利用基于GIS空间分析的GEM-CO2模型,估算珠江流域陆地岩石风化作用消耗大气/土壤空气中的CO2,评价河流流域的碳汇能力。结果表明,珠江流域因岩石溶蚀和风化作用消耗大气/土壤中的CO2量为252×109 mol·a-1(571×103 mol·km-2·a-1),从岩性分析,碳酸盐岩区大气/土壤CO2消耗量为180×109 mol·a-1(1030×103 mol·km-2·a-1),占总量的71.4%。二级流域以西江流域CO2消耗量最大,占珠江流域总CO2消耗量79.4%,北江、东江分别占总量的13.0%、4.9%。珠江流域大气/土壤CO2消耗量大约为世界大河流域平均值的2.3倍。

Estimation of Atmospheric/Soil CO2 Consumption by Rock Weathering in the Pearl River Valley

The atmospheric/soil CO₂ consumption by rock weathering has become the main carbon sink. The flux of CO₂ consumed by rock weathering increases with the increasing carbonate rock outcrop area and the water drainage intensity. In this paper, with the rock, water runoff and water chemistry data of the valley as the main data, the authors estimated the flux of atmospheric/soil CO₂ consumed by chemical erosion of continental rocks in the Pearl River Valley based on a global erosion model (GEM-CO₂) developed by Amiotte Suchet. The total carbon consumption is about 252×109 mol?a^-1 (571×103 mol?km^-2?a^-1), about 71.4% of which are caused by carbonate rocks, with about 180×109 mol?a^-1 (1030×103 mol km^-2?a^-1) CO₂ consumed flux. About 79.4% of the consumption of CO₂ is localized in Xijiang tributary basin, because of a high proportion of carbonate rocks and high humidity in this area. In contrast, the Beijiang tributary basin and the Dongjiang tributary basin only possess 13% and 4.9% of the total CO₂ consumption amount respectively. The flux of atmospheric/soil CO₂ consumed in the Pearl River Valley is 2.3 times higher than the average CO₂ consumption of the major river basins in the world.