CN-122021444-A - Liquid water content calculation method and system based on Qinghai-Tibet plateau frozen soil

CN122021444ACN 122021444 ACN122021444 ACN 122021444ACN-122021444-A

Abstract

The invention provides a method and a system for calculating liquid water content of frozen soil based on Qinghai-Tibet plateau, and relates to the technical field of frozen soil water content calculation. The method comprises the steps of collecting meteorological data, including precipitation, temperature and evaporation and evapotranspiration, and inputting the meteorological data into an improved VIC model to realize real-time calculation of a soil moisture dynamic equation. In the simulation, the variation of the water content in the liquid state and the interaction of environmental factors are considered. And outputting through an analysis model, verifying a calculation result, deeply discussing the water distribution characteristics of the frozen soil area, and providing scientific basis for water resource management and ecological protection. The invention solves the problems that the prior art lacks a refined solid water content and temperature relation established based on an actual measurement observation network and soil texture classification, so that the liquid water content of frozen soil cannot be accurately calculated under the condition of Qinghai-Tibet plateau and the existing model can be effectively improved.

Inventors

ZHOU LE
LIU YUANQING
MA XUEJUN
LV LIN
LI WEI

Assignees

中国地质调查局水文地质环境地质调查中心

Dates

Publication Date: 20260512
Application Date: 20260204

Claims (10)

1. The method for calculating the liquid water content of the frozen soil based on the Qinghai-Tibet plateau is characterized by comprising the following steps of: acquiring soil observation data of a plurality of representative stations on the Qinghai-Tibet plateau at different time periods and different soil layer depths, and performing quality control and arrangement on the soil observation data to obtain an effective observation data set of frozen soil of the Qinghai-Tibet plateau; classifying soil in a frozen soil area of the Qinghai-Tibet plateau according to the Qinghai-Tibet plateau frozen soil effective observation data set to obtain a Qinghai-Tibet plateau frozen soil texture type set; Selecting corresponding temperature and water content samples from the effective observation data set of the Qinghai-Tibet plateau frozen soil according to the soil texture type set of the Qinghai-Tibet plateau frozen soil, and constructing a quantitative relation of solid water content along with the change of soil temperature according to the physical rule of the hydrothermal process of the frozen soil; adjusting and fitting the quantitative relation through preset physical conditions to obtain a relation family of solid water content and soil temperature divided according to the texture; Based on the relation family of the solid water content and the soil temperature divided according to the texture, combining the water storage characteristics and the effective pore characteristics which can participate in freezing of different soil textures, distributing the total water content of the soil between solid water and liquid water, and determining the unified calculation relation of the liquid water content of the frozen soil of the Qinghai-Tibet plateau; Embedding the unified calculation relation of the liquid water content of the Qinghai-Tibet plateau frozen soil into a VIC model to obtain an improved VIC model; And calculating to obtain the liquid water content distribution of the frozen soil area of the Qinghai-Tibet plateau by using the VIC model.
2. The method for calculating the liquid water content of frozen soil based on Qinghai-Tibet plateau of claim 1, wherein the soil observation data comprises: Soil temperature, soil moisture content, and soil texture information.
3. The method for calculating the liquid water content of frozen soil based on the Qinghai-Tibet plateau according to claim 1, wherein the classifying the frozen soil region soil of the Qinghai-Tibet plateau according to the effective observation dataset of the Qinghai-Tibet plateau to obtain the set of soil texture types of the Qinghai-Tibet plateau comprises: Extracting soil-related effective observation data from the Qinghai-Tibet plateau frozen soil effective observation data set, and filling the extracted effective observation data with a missing value, removing an abnormal value and carrying out standardization processing on the extracted effective observation data to obtain a standardized Qinghai-Tibet plateau frozen soil observation data set; establishing soil texture classification standards of Qinghai-Tibet plateau areas by combining soil characteristics of the Qinghai-Tibet plateau; classifying the standardized Tibet plateau frozen soil observation data set by using the Tibet plateau region soil texture classification standard, and classifying soil samples into different quality categories in the Tibet plateau frozen soil region to obtain a Tibet plateau frozen soil texture classification result; and integrating and classifying the soil texture types with the same characteristics according to the Tibet plateau frozen soil texture classification result to obtain a Tibet plateau frozen soil texture type set.
4. A method for calculating liquid water content of frozen soil based on Qinghai-Tibet plateau as claimed in claim 3, wherein the soil texture classification criteria of the Qinghai-Tibet plateau region comprises: Particle size range, moisture characteristics, and physical properties.
5. The method for calculating the liquid water content of the frozen soil based on the Qinghai-Tibet plateau according to claim 1, wherein the selecting corresponding temperature and water content samples from the Qinghai-Tibet plateau frozen soil effective observation data set according to the set of soil texture types of the Qinghai-Tibet plateau frozen soil, and constructing a quantitative relation of solid water content along with the change of soil temperature according to the physical law of the hydrothermal process of the frozen soil comprises the following steps: According to the collection of soil texture types of the Qinghai-Tibet plateau, temperature and water content data corresponding to each soil texture type are screened out from the effective observation data set of the Qinghai-Tibet plateau frozen soil, and temperature and water content samples aiming at different soil texture types are obtained; Calculating the content of solid water according to the physical law of the frozen soil hydrothermal process by using the temperature and water content samples aiming at different soil texture types; Based on the content of the solid water, using the thermophysical experimental data to obtain the relation between the solid water and the temperature, and obtaining the preliminary relation data of the solid water content and the soil temperature; Carrying out statistical analysis on the preliminary relation data of the solid water content and the soil temperature to construct a quantitative relation of the solid water content along with the change of the soil temperature; the quantitative relation expression of the solid water content along with the change of the soil temperature is as follows: ; Wherein, the The water content is solid; Is a constant of the initial solid water content; is the energy conversion constant between solid water and temperature; The correction coefficient is used for the influence of temperature on the solid water content; The soil temperature; is an exponential coefficient of the temperature effect on the amount of solid water.
6. The method for calculating the liquid water content of frozen soil based on Tibet plateau according to claim 1, wherein the step of adjusting and fitting the quantitative relationship by a preset physical condition to obtain a family of relationship between solid water content and soil temperature according to texture classification comprises: setting a preset physical condition set for different soil texture types, wherein the preset physical condition set comprises, for example, saturation, maximum frozen soil depth and temperature range; Fitting the quantitative relation and the preset physical condition set to obtain initial parameters of adjustment and fitting; and carrying out nonlinear adjustment on the initial parameters by using a curve fitting technology, and combining the initial parameters with a preset physical condition set to obtain a relationship family of solid water content and soil temperature.
7. The method for calculating the liquid water content of the frozen soil based on the Qinghai-Tibet plateau according to claim 1, wherein the step of determining the unified calculation relationship of the liquid water content of the frozen soil based on the family of relationship between the solid water content and the soil temperature divided by the texture, by combining the water storable features and the available pore features which can participate in freezing of different soil textures, and by distributing the total water content of the soil between the solid water and the liquid water comprises the following steps: Analyzing and determining water storage characteristics and effective pore characteristics capable of participating in freezing according to different soil texture types to obtain water storage and effective pore characteristic data of the soil texture; based on the water-storable and effective pore characteristic data of the soil texture, calculating the total water content of the soil of each soil texture type to obtain the total water content of each soil texture type; Combining the relation family of the solid water content and the soil temperature according to the texture division, and distributing the total water content of each soil texture type between the solid water and the liquid water to obtain a calculation result of the distribution of the solid water and the liquid water; based on the calculation result of the solid water and liquid water distribution, obtaining a unified calculation relation of the liquid water content of the Qinghai-Tibet plateau frozen soil; the expression of the unified calculation relation of the liquid water content of the Qinghai-Tibet plateau frozen soil is as follows: ; Wherein, the Is liquid water content; is the maximum potential content constant of liquid water; An energy threshold for liquid water transition; To characterize the soil structure and its coefficients affecting the distribution of liquid water; Is the saturation of soil; The soil temperature; Is an exponential coefficient of the temperature effect on the water content of the liquid.
8. The method for calculating the liquid water content of frozen soil based on Tibet plateau of claim 7, wherein the step of combining the texture-based relationship family of solid water content and soil temperature, and distributing the total water content of each soil texture type between solid water and liquid water to obtain a calculation result of solid water and liquid water distribution, comprises: determining an initial total moisture content for each soil texture based on the total moisture content for each soil texture type, wherein the initial total moisture content comprises solid water and liquid water; Extracting solid water content from the total water content of each soil texture type according to the relation family of the solid water content and the soil temperature divided according to the texture, and obtaining solid water content estimation corresponding to each soil texture; Combining the solid water content estimation corresponding to each soil texture with the initial total water content of each soil texture, and calculating to obtain a liquid water content calculation result of each soil texture; And summarizing the solid water content estimation of each soil texture and the liquid water content calculation result of each soil texture to obtain the calculation result of solid water and liquid water distribution.
9. The method for calculating the liquid water content of the frozen soil based on the Qinghai-Tibet plateau according to claim 1, wherein the expression of the improved VIC model is as follows: ; Wherein, the Is the change rate of soil moisture; Is precipitation; to evaporate and evaporate the amount Is the change of the soil water reserves; A regulating factor for influencing the flow of liquid water; Is liquid water content; The water content of the soil in a liquid state under the saturated state is obtained; is a temperature dependent permeability coefficient.
10. The utility model provides a liquid water content computing system based on Qinghai-Tibet plateau frozen soil which characterized in that includes: The data set observation module is used for acquiring soil observation data of a plurality of representative stations on the Qinghai-Tibet plateau in different time periods and different soil layer depths, and performing quality control and arrangement on the soil observation data to obtain an effective observation data set of the Qinghai-Tibet plateau frozen soil; the soil classification module is used for classifying the soil in the frozen soil area of the Qinghai-Tibet plateau according to the Qinghai-Tibet plateau frozen soil effective observation data set to obtain a Qinghai-Tibet plateau frozen soil texture type set; The temperature and water content sample selection module is used for selecting corresponding temperature and water content samples from the Qinghai-Tibet plateau frozen soil effective observation data set according to the Qinghai-Tibet plateau frozen soil texture type set, and constructing a quantitative relation of solid water content along with the change of soil temperature according to the physical rule of the frozen soil hydrothermal process; the relation adjustment and fitting module is used for adjusting and fitting the quantitative relation through preset physical conditions to obtain a relation family of solid water content and soil temperature divided according to the texture; The liquid water content distribution module is used for distributing the total water content of the soil between the solid water and the liquid water based on the relation family of the solid water content and the soil temperature divided according to the texture, combining the water storage characteristics of different soil textures and the effective pore characteristics capable of participating in freezing, and determining the unified calculation relation of the liquid water content of the frozen soil of the Qinghai-Tibet plateau; the model improvement module is used for embedding the unified calculation relation of the liquid water content of the Qinghai-Tibet plateau frozen soil into the VIC model to obtain an improved VIC model; and the liquid water content calculation module is used for calculating and obtaining the liquid water content distribution of the Qinghai-Tibet plateau frozen soil area by using the VIC model.

Description

Liquid water content calculation method and system based on Qinghai-Tibet plateau frozen soil Technical Field The invention relates to the technical field of frozen soil moisture calculation, in particular to a method and a system for calculating liquid water content of frozen soil based on Qinghai-Tibet plateau. Background The Qinghai-Tibet plateau is one of the most sensitive areas to climate change in the global warming background, and permafrost and seasonal frozen soil are widely distributed, and the change of the liquid water content of soil directly affects the earth surface energy balance, hydrologic cycle and ecosystem process. In the existing land hydrologic model and energy balance model, the frozen soil hydrothermal process is generally described by an empirical freezing and thawing relation, and the soil temperature and the soil moisture state are corresponding to estimate the liquid water content distribution and the solid water content distribution under different temperature conditions. The method has certain applicability in low and medium latitude areas and under general soil conditions, and provides basic support for river basin runoff simulation and regional water resource evaluation. Along with the improvement of the observation capability, a systematic soil temperature and humidity observation network is established in the Qinghai-Tibet plateau area, and the information of soil temperature, water content, soil texture and the like on different time and space scales is obtained. The research trend is gradually changed from a simple empirical relationship to the utilization of measured data and physical and chemical properties of soil, and a hydrothermal coupling relationship which is more in line with the characteristics of the frozen soil area is constructed. Attempts have been made to characterize the solid water content with temperature according to the pore structure and freezing characteristics of soils of different textures, and embed such parameterized results into the large-scale Liu Mianmo model, so as to improve the reliability and physical interpretation of simulation results in the high-cold frozen soil region on the premise of maintaining the calculation efficiency. However, the existing method mostly adopts unified or weakly-classified empirical freezing curves, often fails to fully embody the characteristics of complex and changeable soil texture differences and freeze thawing mechanisms of Qinghai-Tibet plateau, lacks a texture specific relation based on the fitting of an observation network data system, and is difficult to accurately express quantitative relation between solid water content and soil temperature. The method has the advantages that in the critical temperature range of freeze thawing conversion, the estimated deviation of the liquid water content is larger, so that the comprehensive simulation precision of the model on the soil heat condition, groundwater supply, surface runoff and evaporation is affected, and the method is not beneficial to fine depiction and future scene estimation of the frozen soil hydrologic process of the Qinghai-Tibet plateau. Disclosure of Invention In order to overcome the defects of the prior art, the invention aims to provide a method and a system for calculating the liquid water content of frozen soil based on Tibet plateau, and solves the problems that the prior art lacks a refined solid water content and temperature relationship established based on an actual measurement observation network and soil texture classification, so that the liquid water content of the frozen soil cannot be accurately calculated under the condition of Tibet plateau, and the existing model can be effectively improved. In order to achieve the above object, the present invention provides the following solutions: A liquid water content calculation method based on Qinghai-Tibet plateau frozen soil comprises the following steps: acquiring soil observation data of a plurality of representative stations on the Qinghai-Tibet plateau at different time periods and different soil layer depths, and performing quality control and arrangement on the soil observation data to obtain an effective observation data set of frozen soil of the Qinghai-Tibet plateau; classifying soil in a frozen soil area of the Qinghai-Tibet plateau according to the Qinghai-Tibet plateau frozen soil effective observation data set to obtain a Qinghai-Tibet plateau frozen soil texture type set; Selecting corresponding temperature and water content samples from the effective observation data set of the Qinghai-Tibet plateau frozen soil according to the soil texture type set of the Qinghai-Tibet plateau frozen soil, and constructing a quantitative relation of solid water content along with the change of soil temperature according to the physical rule of the hydrothermal process of the frozen soil; adjusting and fitting the quantitative relation through preset physical conditions to obtain a r