| Dali-nor Lake is a closed brackish water lake,and is also a representative of plateau lakes in the cold and arid regions of northern China.Under the condition of obvious seasonal transformation,the physical and chemical indexes of the lake water in the Dali-nor Lake Basin have changed significantly,showing its unique regional characteristics.In this paper,based on the measurements total dissolved solids(TDS),stable hydrogen and oxygen isotopes(δ D,δ18O)and the main anions and cations in lake water,river water and shallow groundwater in Frozen and Non-frozen States,a comparative study on the Hydrology and Chemistry characteristics of lakes under Frozen and non-Frozen States was carried out,and the temporal and spatial distribution characteristics of different physical and chemical indexes in Dali-nor Lake were mainly discussed.The replenishment relationship of Dali-nor Lake is analyzed preliminarily.The specific results are as follows:1.In terms of spatial distribution,whether Frozen or Non-frozen States,the content of TDS in the surface water of Dali-nor Lake is higher than that in the bottom water.Relatively,the content of TDS in the bottom water of the lake is more stable,and the TDS in the surface water is greatly affected by the changes of external climate and environment during the alternation of winter and summer seasons,especially in the Non-frozen State.2.The(LWML)equation of the Meteoric Water Line in the Dali-nor Lake area is:8 D=7.03δ18O-0.01(R2=0.89,n=18),which shows a strong effect of secondary evaporation.At the same time,when comparing the δ D and δ18O values of river water,lake water,shallow groundwater and atmospheric precipitation in the Dali-nor Lake basin,it can be found that there is a close relationship between river water,surface lake water and atmospheric precipitation.Especially in the Non-Frozen State,under the influence of strong evaporation,the δ D and δ18O values of lake Gater and river water are obviously positive,while the shallow groundwater tends to be stable and is weakly affected by seasonal succession.3.The hydrochemistry type was Na+-Cl--HCO3-for Dali-nor lake,Na+-Ca2+-Cl--HCO3-for Gong Geer River,Na+-Mg2+-HCO3--Cl-for Sha Li River,Na+-Ca2+-HCO3-for Liang Zi River,and Na+-Mg2+-HCO3-for Hao Lai River.Using Na+,HCO3-and Cl-,as general indicators to analyze the supply relationship of Lake Dali-nor Lake,the results show that the concentration of each ion in the Frozen State is higher than that in the Non-frozen State,and most points in the surface water in winter It is higher than the bottom water,which indicates that the condensation effect is stronger than the summer evaporation effect during icing.Moreover,in summer,the lake water will be affected by the input of external water bodies such as atmospheric precipitation.4.Through comprehensive analysis of the total dissolved solids(TDS),δ D,δ18O,Na+,HCO3-and Cl-plasmas in the lake water at different periods,it was found that during the Non-frozen State,the entire lake area was open,which was helpful to the direction of shallow groundwater The lake replenishment movement has made its replenishment ability significant;while the effect of recharge of shallow groundwater during the Frozen State is not obvious.River water only plays a seasonal regional recharge role in the entire hydrological cycle.The replenishment capacity of each river and spring water will be affected by climatic conditions and human activities.In addition,the differences in the concentrations of Na+,HCO3-and Cl-in the lake surface and bottom water are not obvious.At the same time,there are some differences in the characteristics of the ions.Therefore,it is not appropriate to use a single Ions are traced.The current results show that,when comparing the difference in the concentration of the dominant ions commonly contained in lake water,river water,and shallow groundwater,although it can serve as a simple indicator,its tracking ability is far inferior to TDS,δ D,δ18O and other indicators.Of course,the results need further analysis. |
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