Investigation And Analysis Of Ice Temperature Profiles Of Shifosi Reservoir And Wuliangsuhai Lake

Freezing phenomena occur in rivers,lakes and reservoirs in high latitudes in winter.China is located in the middle latitude and controlled by the Siberian cold current.Seasonal freezing occurs in the inland waters of Northwest,Northeast,North China and Bohai Sea.Among them,ice thickness is an important physical parameter in the field of ice engineering,and also an important parameter of ice generation and dissipation process.Therefore,ice thickness assessment is of great significance.As one of the simple thermodynamic models to evaluate ice thickness,Stephen model can establish the statistical relationship between ice thickness and negative accumulated temperature.One of the important hypotheses is that the heat conduction in ice only occurs along the depth direction and presents a unidirectional linear distribution.In fact,there are few ice temperature profiles that meet the ideal conditions of Stephen's model in China's mid-latitude region.In order to explore the distribution of ice temperature profiles,based on in situ observation data of river ice in dynamic water body of Shifosi Reservoir in Liaohe River and lake ice in static water body of Wuliangsuhai Lake in Yellow River,the corresponding environmental factors such as temperature,radiation and wind speed were investigated and counted when the ice temperature profiles appeared,and the relationship between the occurrence time of ice temperature profiles and different temperatures was also studied.And the application effect of Stephen's equation is analyzed.Firstly,the ice temperature profile is divided into six types.The linear fitting coefficient k,correlation coefficient r,occurrence time and proportion of each ice temperature profile type during the statistical observation period are calculated.The corresponding temperature,irradiance and wind speed distribution of each ice temperature profile type when it appears.Then the time difference between the occurrence time of each ice temperature profile and sunrise time or sunset time is calculated,and the relationship between the occurrence time difference and daily average temperature,sunrise temperature,sunset temperature,temperature of each ice temperature profile and their linear fitting coefficients k,b and correlation coefficients r are analyzed.It is found that the occurrence time of each ice temperature profile is different from sunrise time and sunset time.The linear fitting degree of temperature at sunrise?or sunset?is relatively good.Finally,the fitting coefficient A₀ of Stephen's equation in all ice temperature profiles and the weighted average value of the average coefficients A₀ of Stephen's equation in each ice temperature profile are compared and analyzed.It is found that the two coefficients are comparatively close,which shows that the average coefficients A₀ of Stephen's equation in each ice temperature profile are reasonable.