中国岩溶2026，Vol.45Issue(3)：539-552,14.DOI:10.11932/karst20260304
云南省岩石风化碳汇通量估算及时空演变分析
Estimation of karst carbon sink fluxes from rock weathering and analysis of their spatiotemporal dynamics in Yunnan Province
摘要
Abstract
Research on the global transfer of"carbon sources"and"carbon sinks"has revealed the potential existence of previously unidentified carbon sinks within the continental biosphere.Among these,the dynamic chemical process of rock weathering constitute a major carbon sink capable of sequestering atmospheric CO2.The carbon sink from rock weathering constitutes an integral component of this"missing carbon sink."Notebly,the distinctive biogeochemical process of rock,particularly in karst landscapes,has been increasingly recognized as a critical and persistent carbon sink.Carbonate minerals dissolve through carbonic acid formed from atmospheric or soil-derived CO2 and water,generating bicarbonate ions that are transported via river systems to the oceans,thereby sequestering carbon over geological timescales.Therefore,accurately estimating the magnitude of the carbon sink from rock weathering and understanding its spatiotemporal dynamics are essential for regional carbon assessments,climate change mitigation strategies,and policy formulation in karst-dominated regions.Yunnan Province,situated in Southwest China,is one of the country's primary karst development areas,characterized by diverse soluble and silicate rock types,making it an ideal natural laboratory for such investigations.This study aims to quantify carbon sink fluxes from rock weathering in Yunnan Province from 2001 to 2020,analyze its spatiotemporal evolution characteristics,and project future trends under ongoing environmental changes. Based on a detailed classification of soluble and insoluble rocks within Yunnan Province,this study employed the well-established Global Erosion Model for CO2 consumption(GEM-CO2)model.This model estimates the CO2 consumption flux(FCO2)resulting from the chemical weathering of different rock types by integrating surface runoff data with specific lithological coefficients(a)that represent the weathering potential of each rock.The fundamental equation is(FCO2=Q·a),where(Q)is the annual surface runoff.Runoff(Q)was calculated using the Turc method,which estimates actual evaporation(E)based on annual precipitation(P)and temperature(T)data,with(Q)derived as(P-E).High-resolution spatial data,including a 1∶500,000 geological map(resampled to a 1-km grid)and long-term meteorological datasets(precipitation and temperature)from 2001 to 2020,were utilized as primary inputs.Following flux estimation,a suite of robust statistical and geospatial methods was applied.The Theil-Sen Median trend analysis and Mann-Kendall significance test were used to detect monotonic trends in the carbon sink fluxes over the two-decade period.The coefficient of variation(CV)was calculated to assess the stability and variability of fluxes.Finally,to predict the future persistence or reversal of these trends,the Hurst exponent,derived from Rescaled Range(R/S)analysis,was calculated and combined with Sen's slope to generate a map of future trend predictions. The key findings of this study are multifaceted,(1)From 2001 to 2020,the estimated annual average CO2 consumption flux attributable to rock weathering in Yunnan Province was 187.79 × 103 mol·km-2·a-1.This corresponds to a total CO2 consumption mass of approximately 63.12×106 t and a total carbon mass of 17.38×106 t over the two decades.Significant disparities were observed among different types of lithology in their contribution to the carbon sink.Carbonate rocks exhibited the highest average annual CO2 consumption flux at 582.91×103 mol·km-2·a-1,accounting for 53.95％of the total CO2 consumed,thus establishing them as the predominant rock type driving the weathering carbon sink in the province.This was followed by shale(207.22×103 mol·km-2·a-1),acid volcanic rocks(87.55×103 mol·km-2·a-1),sandstone(56.29×103 mol·km-2·a-1),and metamorphic and plutonic rocks(51.2×103 mol·km-2·a-1).(2)The spatial distribution of the rock weathering carbon sink flux demonstrated a distinct pattern characterized as"high in the surrounding areas and low in the central region".High-flux zones were primarily concentrated in eastern Yunnan,with values gradually increasing from north to south,and in the border regions of western Yunnan.In contrast,low-flux zones were predominantly located in central and northern Yunnan.The coefficient of variation(CV)for the flux across the province ranged from 0 to 0.64,indicating varying degrees of temporal stability.Areas of high variability(CV≥0.35)constituted 14.75％of the province's area and were mainly situated in central Yunnan(around Kunming,Chuxiong,and Dali),forming a pattern of"high variability in the center and low variability in the surrounding areas".This pattern suggests that the carbon sink in central Yunnan is more sensitive to interannual environmental fluctuations,potentially influenced by intensive human activities and specific lithological compositions(sandstone and shale).(3)Temporal trend analysis revealed a slight overall declining trend in total CO2 consumption mass from 2001 to 2020,with a linear slope of-0.005 5,although significant interannual fluctuations were observed.Theil-Sen analysis indicated that areas exhibiting a decreasing trend(approximately 76.93％of the province's area with significant change)were more extensive than those showing an increasing trend(22.98％),with the most pronounced decreases occurring in northwestern and central Yunnan and increases concentrated in northeastern Yunnan(e.g.,Zhaotong).The Hurst exponent for the carbon sink flux across the province ranged from 0.30 to 0.63,indicating a complex mix of future behaviors.Approximately 57.18％of the area exhibited a Hurst index less than 0.5,suggesting an anti-persistent trend(future reversal of the past trend),while 42.82％displayed an index greater than 0.5,indicating a persistent trend.By integrating Sen's slope and the Hurst index,future predictions were derived.It is projected that areas with an increasing trend in the carbon sink flux from rock weathering will cover approximately 39.86％of the province,mainly concentrated in eastern and northwestern Yunnan.Conversely,areas predicted to experience a continuous decrease will account for approximately 34.86％of the province,predominantly distributed in central,northeastern,and parts of eastern Yunnan. This study provides a comprehensive quantitative assessment of the carbon sink from rock weathering in Yunnan Province over the past two decades.The results highlight the dominant role of carbonate rocks and reveal significant spatial heterogeneity and temporal variability in this carbon sink,primarily driven by the interplay of lithology,climate(precipitation and temperature),and potentially human activities.The predictive analysis offers valuable insight,suggesting a slight net increase in future sink areas despite recent declining trends.These findings provide crucial scientific evidences for understanding the regional carbon budget,validate the efficacy of the GEM-CO2 model for large-scale assessments,and support the formulation of targeted ecological restoration and carbon management policies in Yunnan Province and similar karst regions worldwide.关键词
岩石风化碳汇/GEM-CO2模型/碳汇通量/时空演变/趋势预测Key words
karst carbon sink from rock weathering/GEM-CO2 model/carbon sink flux/spatiotemporal evolution/trend prediction分类
天文与地球科学引用本文复制引用
黄训朝,叶江霞,殷晓洁,王妍,柳增,唐继敏..云南省岩石风化碳汇通量估算及时空演变分析[J].中国岩溶,2026,45(3):539-552,14.基金项目
云南省"兴滇英才支持计划"青年人才项目(XDYC-QNRC-2022-0251) （XDYC-QNRC-2022-0251）
云南省重点研发计划项目(202503AP140004) （202503AP140004）
云南省重大科技专项(202202AD080010) （202202AD080010）
