Research On Electrical Properties Of Dome-A Ice Core

The paleoclimate information recorded by the ice cores is often extracted and analyzed by chemical and physical indicators.The electrical properties of ice cores are physical indicators for analyzing ice cores,and have important research significance.In order to quantify the response of the ice core under AC and DC,ECM?Electric Conductivity Measurement?and DEP?Dielectric Profiling?are proposed and applied to the analysis of the electrical properties of ice cores in the field.However,the technical parameters and methods for measuring ice cores by ECM and DEP need to be explored for field conditions,and the impact of changes in ice core components on test signals is not completely clear.Therefore,artificial ice cores with different ion species and concentration gradients were made based on the control variable method.We measure these artificial ice cores by Chinese self-developed ice core electrical property measurement device.We explored the relationship between electrical signals and chemical ion species,ion concentration,ice core crystallization rate,ice core gas content,and ice core dust content.From a microscopic perspective,we can make a reasonable explanation of the experimental results through the defect mechanism.Besides we can make a qualitative prediction of the unknown results.From a macro perspective,the experimental results can be linked with the model simulation,which is conducive to the quantitative prediction of the unknown results.Next,during the 26th Antarctic Scientific Expedition in China,the electrical properties of a KL02 ice core with a total length of 133.44m were drilled at a distance of 0.57m from the surface in the Dome-A area.Simulation results show that the DEP signal?has a clear linear relationship with the H⁺,Cl^-and NH₄⁺concentrations in the ice core,the relationship is?=0.24[H⁺]+0.0047[Cl^-]+0.0039[NH₄⁺]+3.6?R²=0.91?;the ECM signal I is significantly correlated with H⁺in the ice core,and the relationship is:I=0.025[H⁺]^1.426+0.0523?R²=0.97?.In addition,the ice core crystallization rate with dopant HCl has a positive correlation with DEP signal?.The ice core gas content,ice core dust?grass ash?content,ice core has a negative correlation with DEP and ECM signal.The abnormally high grass ash content in ice core cause the ECM signal rise.The reason for the increase is that the concentration of salt ions exceeds the threshold,and the free salt water causes the current to conduct.It indicate that ice cores containing excessively high concentration of salt ions are not suitable for ECM measurement.The signal interferes with the signal generated by the normal ion defect and affects the correct interpretation of the result.Next,we measured the electrical properties of KL02 ice core based on the simulation experiment conclusions.KL02 were drilled at a distance of 0.57m from the surface of the Dome-A area during the inland ice sheet scientific expedition of the CHINARE 26th.KL02 is 133.44m.Nowadays,looking for ancient ice cores with time scale exceeding 1Ma has become the focus of scientific research in Antarctica.According to the calculation results of ice body dynamics models and a series of factors such as accumulation rate,ice flow,ice thickness,ice at the bottom of the Dome-A age can reach 1.1Ma.The Dome-A is the most promising Antarctic research hotspot for drilling ice scales larger than a million years.So Dome-A has important scientific research significance in ice core climate and environmental changes,polar snow and ice processes.The electrical properties of the KL02 ice core are analyzed through the ice core electrical measurement equipment,which can provide technical support and data support for subsequent deeper ice core research.In this paper,the DEP signal is used to study the KL02 ice core.Density noise is eliminated by the Looyenga model.After z-score normalization,it is determined that the peak that meets the"2?standard"is a special event age mark layer.We find 29volcanic events which meet the“2?standard”peak.By comparing DA2005,M150,and CV ice cores,the corresponding famous volcanic events among these peaks were determined.In addition,the annual average accumulation rate between the famous volcanic events was calculated based on the water equivalent.The results show that the average annual accumulation rate of KL02 in recent 740 years is 0.02303m w.e.a^-1.The average annual accumulation rate of KL02 in recent 2000 years is 0.02383m w.e.a^-1.