为研究天津平原地下水的水化学特征和碳酸盐风化碳汇特征的时空演变，在研究区内利用2020—2022年的采样数据分别进行ArcGIS反距离权重空间演化分析、聚类分析以及SPSS数据统计分析等工作。研究表明：在时空演化特征方面，2020—2022年Na+和Cl?的质量浓度呈现逐年增加趋势，地下水中的咸水含量逐渐增加，其中在116°63′E～116°84′E、117°12′E～117°47′E最为显著，Ca2++Mg2+与HCO?3+SO24?的质量浓度比值均大于1，天津平原地下水的咸水Ca2++Mg2+与HCO?3+SO2-4的毫克当量浓度比值均小于1；在天津平原地下水阴阳离子的空间分布中，地下水中的阳离子Na+、Ca2+的质量浓度区间分别为[104.00，4 812.21] mg/L、[38.30，713.67] mg/L，阴离子Cl?、HCO?3的质量浓度区间分别为[73.60，11 282.49] mg/L、[78.00，539.46] mg/L；在海咸水入侵的影响方面，通过对比和分析地下水中的Cl?和其他离子（Na+、Ca2+）质量浓度比例发现，靠近滨海区域，地下水的咸化程度较高，进一步实证分析发现海水入侵对地下水化学组成有显著影响Δ[Na+]=4 708.21 mg/L，Δ[Cl?]=11 208.89 mg/L）；在碳酸盐风化碳汇特征分析方面，天津平原西部地区的地下水碳酸盐风化碳汇量减少，而东部地区的地下水碳酸盐风化碳汇量增加，其中Ca2+、Mg2+的质量浓度对碳酸盐风化碳汇具有显著的正向影响（B[Ca2+]=0.910，P=0.03；B[Mg2+]=0.312，P=0.09）。

Currently, owing to the significant impact of carbonate weathering processes, the chemical composition of groundwater in the Tianjin Plain exhibits a distinct horizontal zonation pattern, both from north to south and from north to east. This zonation is a result of complex geological and hydrogeological interactions that shape the unique characteristics of the groundwater in this region. The pH value of the groundwater typically ranges between 7.0 and 8.5, classifying it as neutral to slightly alkaline. This pH range is influenced by various factors, including the mineralogy of the aquifer materials and the presence of dissolved ions. One notable feature of the groundwater in the Tianjin Plain is its high total dissolved solids (TDS) content. This elevated TDS level is primarily attributed to the abundance of specific ions, notably sodium (Na+), chloride (Cl?), bicarbonate (HCO?3)，and calcium (Ca2+) ions. In order to study the hydrochemical characteristics of groundwater in Tianjin Plain and the spatial and temporal evolution characteristics of carbonate weathered carbon sinks, ArcGIS antidistance weight spatial evolution analysis, cluster analysis and SPSS data statistical analysis were conducted by the sampling data from 2020 to 2022 in the research area. It is found that in terms of spatial and temporal evolution characteristics, the mass concentration of Na+ and Cl? increased gradually from 2020 to 2022, and the content of salt water in the groundwater between 116°63′E-116°84′E、117°12′E-117°47′E, Ca2++ Mg2+to HCO?3+SO24? was less than 1. In the latitudinal spatial distribution of ions in Tianjin Plain, the mass concentration interval of cations Na+ and Ca2+ in groundwater is [104 mg/L,4 812.21 mg/L], Ca2+[38.3 mg/L,713.67 mg/L], and the mass concentration interval of anions Cl?and HCO?3 is [73.6 mg/L, 11 282.49 mg/L], [78 mg/L, 539.46 mg/L], respectively. In terms of the influence of salinity water intrusion, by comparing and analyzing the concentration ratio of Cl? and other ions (Na+, Ca2+) in groundwater, it is found that the salinity degree of groundwater is high near the coastal area, and further empirical analysis found that seawater intrusion has a significant impact on the chemical composition of groundwater (Δ [Na+]=4 708.21mg/L,Δ[Cl?]=11 208.89mg/L). In terms of characteristic analysis of carbonate weathered carbon sink, the weathered carbon sink of groundwater in the western area of Tianjin Plain decreased, while the eastern area increased, and the mass concentration of Ca2+ and Mg2+had a significant positive effect on carbonate weathered carbon sink (B [Ca2+]=0.910,p=0.03; B[Mg2+]=0.312,p=0.09). The results further verify the weathering of groundwater carbonate in Tianjin Plain and the relationship between the chemical characteristics of groundwater. In terms of spatial and temporal evolution characteristics, the mass concentration of Na+ and Cl? showed a trend of increasing year by year from 2020 to 2022, indicating that the salt water content in groundwater was gradually increasing. In terms of the impact of brine intrusion, the coastal area, namely the area with higher longitude, showed a higher salinity of groundwater, indicating that seawater intrusion had a significant influence on the chemical composition of groundwater. In terms of the characteristic analysis of carbonate weathered carbon sink, the carbonate weathered carbon sink of groundwater in the western area of Tianjin Plain decreased, while the amount of groundwater carbonate in the eastern region increased, and the mass concentration of Ca2+ and Mg 2+ had a significant positive effect on the carbonate weathered carbon sink. Compared with southwest karst region and the loess plateau region, it is found that although these areas of rock dissolution and carbon sink effect in common, but the Tianjin Plain rock type, dissolution rate and climate conditions, which leads to the carbonate weathering carbon sink characteristics and influencing factors, also has certain uniqueness.