Spatiotemporal evolution of carbon sequestration of limestone weathering in China

作     者：Huiwen LI Shijie WANG Xiaoyong BAI Yue CAO Luhua WU 

作者机构：State Key Laboratory of Environmental Geochemistry Institute of Geochemistry Chinese Academy of Sciences Puding Comprehensive Karst Research and Experimental Station Institute of Geochemistry Chinese Academy of Sciences and Science and Technology Department of Guizhou Province University of Chinese Academy of Sciences 

出 版 物：《Science China Earth Sciences》 (中国科学（地球科学英文版）)

年 卷 期：2019年第62卷第6期

页      面：974-991页

核心收录：

学科分类：0709[理学-地质学] 081803[工学-地质工程] 07[理学] 08[工学] 0818[工学-地质资源与地质工程] 

基　　金：supported by the United Fund of Karst Science Research Center (Grant No. U1612441) the National Key Research Program of China (Grant Nos. 2016YFC0502102 & 2016YFC0502300) the "Western Light" Talent Training Plan of Chinese Academy of Sciences (Class A 2018) the Chinese Academy of Sciences and Technology Services Network Program (Grant Nos. KFJ-STS-ZDTP-036) the International Cooperation Agency International Partnership Program (Grant Nos. 132852KYSB20170029 & 2014-3) the Guizhou High-Level Innovative Talent Training Program "Ten" Level Talents Program (Grant No. 2016-5648) the National Natural Science Foundation of China (Grant Nos. 41571130074 & 41571130042) the Science and Technology Plan of Guizhou Province of China (Grant No. 2017-2966) 

主　　题：Limestone Chemical weathering carbon sink Spatiotemporal evolution Dissolution Random forest 

摘      要：Carbonate carbon sequestration(CS) can aid in solving the problem of terrestrial residual carbon sinks and imbalances in the global carbon budget. Thus, complete understanding of the magnitude, spatiotemporal distribution, and evolution of this sequestration is highly desirable. On the basis of random forest regression and maximal potential dissolution model for carbonate, we estimated the CS of typical carbonate weathering in China from 2000 to 2014, that is, the sequestration of limestone weathering, using long-term ecologic, meteorological, hydrological raster data, and monitored data from 44 watersheds in China and surrounding regions. We extended our analyses by systematically exploring the spatiotemporal pattern and evolution trend of the flux and total sequestration. High levels of ionic activity coefficients of Ca^(2+) and HCO_3^- in limestone regions were observed to be mainly distributed in Northern and Northwestern China with a clear gradient from northwest to southeast. With a contrary spatial pattern, the annual average CS flux(CSF) of limestone weathering in China was estimated to be 4.28 t C km^(-2) yr^(-1), with high values mainly in the karst zones in Southeastern China. The mean CSF in different latitudes showed that Southern China(south of 28.14°N) was the region with the largest interannual fluctuation of flux and CSF increases as latitude decreases. The mean CSF in subtropical and tropical(TR) regions was the maximum of all major climate types, and for the frigid(F), mid-temperate(MTE), warm temperate(WTE), and temperate(TE) major climates; the CSF in the desert(D)subdivided climate was the minimum of these climates. By contrast, the values in grassland(G) and broad-leaved forest subdivided climate were the maximum. The pixel-based trend analysis indicated that the CSF of limestone weathering in China was slightly increasing in the period 2000–2014 with a rate of 0.036 t C km^(-2) yr^(-1). Furthermore, the annual total CS was estimated to be 7.0