Method and system for calculating debris flow rate in high-cold region and electronic equipment

Abstract

The invention relates to the technical field of debris flow, and provides a calculation method and system for debris flow in an alpine region and electronic equipment, and the method comprises the steps: obtaining meteorological data, including surface temperature and hourly precipitation, of an alpine region monitoring station, and obtaining snowfall and rainfall based on the meteorological data; based on the meteorological data, the snowfall and the rainfall, accumulated snow runoff data, runoff data generated by glacier melting, rainfall-driven debris flow gully opening flow data and underground water flow data of the high-cold region monitoring station are calculated respectively; and calculating debris flow total runoff data of the high-cold region monitoring station according to the accumulated snow runoff data of the high-cold region monitoring station, the runoff data generated by glacier melting, the rainfall-driven debris flow gully opening flow data and the underground water flow data.

Description

Technical Field

[0001] The invention relates to the technical field of debris flow flow, and in particular to a calculation method, system and electronic equipment for debris flow flow in alpine areas. Background Art

[0002] Due to the high altitude, cold climate, undulating terrain and fragile ecological environment, alpine areas are prone to debris flow disasters. Debris flows are characterized by sudden outbreaks, fast flow rates, concentrated energy and strong destructive power, posing a serious threat to the safety of life and property of mountain residents and infrastructure such as transportation and energy. Traditionally, debris flows in mountainous areas are mostly driven by heavy rainfall; however, in alpine areas, snowmelt and icemelt often become important triggering factors, especially when rain and snow interact and the temperature rises sharply, the disaster process is more complicated, and the scale and impact range of the debris flows formed are often significantly increased.

[0003] At the same time, observation data in alpine areas are extremely scarce: due to the harsh climate and inconvenient transportation, the meteorological station network is small and not representative enough, and the terrain is undulating and the vertical difference in temperature is obvious, which makes it difficult for the traditional rain-source debris flow model (mainly based on rainfall thresholds and empirical judgment) to accurately describe the ice and snow replenishment process in alpine areas. Although the hydrological model can provide a basic framework for the precipitation-runoff relationship, the snow accumulation process (snow cover and melting, snow and ice energy balance, etc.) in the alpine areas shows strong spatiotemporal variation. It is often impossible to obtain accurate snow volume and melting time series by relying on only a small number of stations or simple interpolation.

[0004] In addition, with global warming, glaciers in high-cold regions are retreating and permafrost degradation is intensifying, leading to an increasingly prominent impact of mountain ice and snow on hydrological processes and debris flow triggering. In order to improve the simulation and prediction accuracy of these complex processes, it is necessary to use multi-source remote sensing (such as optical, microwave, etc.) and ground observation fusion to dynamically correct the evolution of snow and ice reserves, and provide more accurate input conditions for the formation and flow process of snowmelt or icemelt driven debris flows.

[0005] The current methods for predicting debris flow disasters in alpine areas are mostly based on precipitation and temperature thresholds to distinguish between rainfall-type and snowmelt-type triggering mechanisms. However, due to the particularity of the mountainous environment in alpine areas and the limited monitoring data, there is still a lack of scientific and effective simulation and identification of debris flow processes triggered by rain and snow fusion. In general, the existing methods have the following main shortcomings: (1) Hydrological models cannot accurately simulate the hydrodynamic process of debris flows At present, the hydrodynamic behavior of debris flows is often simplified to ordinary runoff or shallow water flow, which cannot reflect the strong coupling between particles, mud and water phases. The runoff generation and confluence algorithms in hydrological models focus on the precipitation-runoff relationship, but lack a targeted description of debris flow processes with high sand content and complex dynamic characteristics, resulting in large deviations in the estimation of disaster scale and flow rate.

[0006] (2) Snow cover simulation has deviations, which seriously affects the estimation of snowmelt water The distribution and dynamic process of snow in alpine areas have strong spatial heterogeneity and seasonal changes. The traditional estimation of snow cover, snow thickness or snow water equivalent based on interpolation of meteorological stations has large uncertainties. In addition, the vertical temperature changes caused by complex terrain, wind-blown snow processes and local microclimate effects all make the model's simulation accuracy of snow and snowmelt processes insufficient, making it difficult to accurately quantify snowmelt runoff in alpine areas.

[0007] (3) Debris flow models are mainly targeted at rainfall-driven types, and lack systematic applicability to rain-snow mixed triggering types. Most existing debris flow forecasting and risk assessment models are based on a single rainfall triggering condition, and do not adequately consider the driving characteristics of rain-snow mixing and snow remelting. In alpine areas, peak flows caused by sudden snowmelt or rain-snow mixing usually present uneven temporal and spatial distribution and unstable critical conditions for starting. It is difficult for the model to take into account debris flow source replenishment, snowmelt erosion and hydrodynamic evolution, making the identification and prediction of debris flows triggered by rain-snow interaction still face huge challenges. Summary of the invention

[0008] In view of the above problems, the present invention is proposed to provide a method, device and electronic equipment for calculating debris flow in high-altitude cold areas that overcome the above problems.

[0009] One aspect of the present invention provides a method for calculating debris flow in alpine regions, the method comprising: Obtaining meteorological data including surface air temperature and hourly precipitation from monitoring stations in high-cold areas, and obtaining snowfall and rainfall based on the meteorological data; Based on the meteorological data, the snowfall and the rainfall, respectively calculate the snow runoff data, the runoff data generated by glacier melting, the debris flow gully flow data driven by rainfall and the groundwater flow data of the monitoring station in the alpine region; The total runoff data of debris flow at the monitoring station in the alpine area is calculated based on the snow runoff data, the runoff data generated by glacier melting, the debris flow gully flow data driven by rainfall, and the groundwater flow data at the monitoring station in the alpine area.

[0010] Preferably, obtaining snowfall and rainfall based on the meteorological data includes: Calculating the conditional frequency of snowfall using a hyperbolic tangent function and the surface air temperature in the meteorological data; The snowfall amount and rainfall amount at the monitoring station in the high-cold area are calculated respectively by using the conditional frequency of snowfall and the hourly precipitation in the meteorological data.

[0011] Preferably, calculating the snow runoff data of the high-cold area monitoring station based on the meteorological data, the snowfall and the rainfall includes: Calculating the potential snowmelt at the current moment based on the degree-time factor model and the surface air temperature in the meteorological data, and calculating the actual snowmelt at the current moment based on the potential snowmelt at the current moment; Calculate the snow reserve at the current moment based on the surface air temperature in the meteorological data, the snowfall amount and the actual snowmelt amount at the current moment; Calculate the amount of meltwater in the snow layer at the current moment based on the surface air temperature in the meteorological data, the rainfall and the snow reserve at the current moment; Based on the surface air temperature in the meteorological data, the rainfall, the actual snowmelt amount at the current moment and the meltwater amount in the snow layer at the current moment, the snow runoff data at the high-cold area monitoring station at the current moment is calculated.

[0012] Preferably, calculating the runoff data generated by glacier melting at the alpine region monitoring station based on the meteorological data, the snowfall and the rainfall includes: Based on the degree-time factor model and the surface air temperature in the meteorological data, the melting amount of the glacier without rock cover and the melting amount of the glacier with rock cover are calculated respectively; Calculating total glacier melt based on the melt of the glacier without debris cover and the melt of the glacier with debris cover; Based on the total glacier melt volume and the configured glacier runoff coefficient, the runoff data generated by the glacier melt at the alpine area monitoring station is calculated.

[0013] Preferably, based on the meteorological data, the snowfall and the rainfall, calculating the rainfall-driven debris flow gully mouth flow data of the high-cold area monitoring station includes: Based on the debris flow erosion intensity and debris flow runoff equation of the monitoring station in the alpine region, the runoff height, runoff velocity and runoff depth of the debris flow are obtained; Based on the runoff height, runoff velocity and runoff depth of the debris flow movement, the rainfall-driven debris flow gully mouth flow data of the alpine region monitoring station is calculated.

[0014] Preferably, calculating the groundwater flow data of the high-cold area monitoring station based on the meteorological data, the snowfall and the rainfall includes: The groundwater depth and soil characteristics of the monitoring station in the alpine region, and based on the groundwater depth and soil characteristics, calculating the groundwater recharge at the current moment; Based on the groundwater recharge at the current moment, the groundwater flow rate flowing into the main river channel at the high-cold area monitoring station at the current moment is calculated.

[0015] Preferably, according to the snow runoff data, the runoff data generated by glacier melting, the debris flow gully flow data driven by rainfall and the groundwater flow data at the monitoring station in the alpine region, the total runoff data of the debris flow at the monitoring station in the alpine region is calculated, which includes: By processing the snow runoff data, the runoff data generated by glacier melting, the debris flow gully flow data driven by rainfall, and the groundwater flow data, the total runoff data of the debris flow at the high-cold area monitoring station is obtained.

[0016] Another aspect of the present invention provides a system for calculating debris flow in high-cold areas, comprising: An acquisition module is used to acquire meteorological data including surface air temperature and hourly precipitation at monitoring stations in high-cold areas, and obtain snowfall and rainfall based on the meteorological data; A first calculation module is used to calculate the snow runoff data, the runoff data generated by glacier melting, the debris flow gully flow data driven by rainfall, and the groundwater flow data of the monitoring station in the high-cold area based on the meteorological data, the snowfall, and the rainfall; The second calculation module is used to calculate the total runoff data of the debris flow at the monitoring station in the high-cold area based on the snow runoff data, the runoff data generated by glacier melting, the debris flow gully flow data driven by rainfall and the groundwater flow data at the monitoring station in the high-cold area.

[0017] Preferably, the acquisition module is specifically used to calculate the conditional frequency of snowfall using the hyperbolic tangent function and the surface air temperature in the meteorological data; and to calculate the snowfall and rainfall at the high-cold area monitoring station using the conditional frequency of snowfall and the hourly precipitation in the meteorological data.

[0018] Another aspect of the present invention provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor; when the computer program is executed by the processor, the steps of the method for calculating debris flow in high-altitude cold areas as described above are implemented.

[0019] The method, system and electronic device for calculating debris flow in high-cold areas provided by the embodiment of the present invention obtains meteorological data including surface air temperature and hourly precipitation of monitoring stations in high-cold areas, and obtains snowfall and rainfall based on the meteorological data; based on the meteorological data, the snowfall and rainfall, respectively calculates snow runoff data, runoff data generated by glacier melting, rainfall-driven debris flow gully mouth flow data and groundwater flow data of the monitoring stations in high-cold areas; according to the snow runoff data, runoff data generated by glacier melting, rainfall-driven debris flow gully mouth flow data and groundwater flow data of the monitoring stations in high-cold areas, calculates the total runoff data of debris flow at the monitoring stations in high-cold areas. The method for calculating debris flow in high-cold areas of the present invention can couple the dynamic changes of snow accumulation and take into account the dynamic characteristics of debris flow, so as to better simulate and predict the peak flow and disaster process triggered by "rain, snow (ice) mixing". By incorporating multi-source remote sensing correction into the snowmelt calculation of the hydrological model and coupling the snow and ice runoff with the debris flow model, we can make up for the deficiency of the existing debris flow model in being limited to rainfall-driven model, and provide more scientific and effective technical support for the prevention and emergency management of debris flow disasters in high-altitude and data-deficient areas.

[0020] In summary, the present invention has the following beneficial effects: (1) Accurately describe the mechanism of debris flow triggered by snowmelt - by coupling the snowmelt process model with the debris flow dynamics model, the impact of ice and snow replenishment on peak flow and start-up hours is fully considered, overcoming the limitation of traditional models that only target rainfall triggering. This method can effectively identify the triggering conditions of "rain, snow, and ice superposition" and pure snowmelt, significantly improving the accuracy and timeliness of debris flow prediction in high-altitude cold areas; (2) Dynamic update and multi-source data fusion - With the help of remote sensing products and ground monitoring data, the snow cover and snowmelt process are corrected in real time or quasi-real time to make up for the lack of data caused by the scarcity of stations in the alpine areas and complex terrain. The use of multi-source remote sensing data to dynamically update the snow state makes the debris flow model more sensitive in capturing events such as extreme weather or rapid warming, further improving the accuracy and stability of flow simulation; (3) Support disaster warning and decision-making - It can be seamlessly connected with the regional emergency management system or warning platform, combined with the quantitative simulation of the scale and impact range of debris flow, to provide scientific support for the warning and disposal of mixed rain, snow and ice disasters in high-altitude cold areas. Through the refined coupling of ice melting / snow-runoff mechanism and debris flow dynamics, this invention has great application value for debris flow risk assessment and disaster prevention and mitigation planning in complex environments in high-altitude cold areas, and significantly makes up for the lack of applicability of existing debris flow models in high-altitude cold areas.

[0021] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented according to the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only used for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. In the accompanying drawings: Figure 1 A flow chart of a method for calculating debris flow in high-cold areas proposed in an embodiment of the present invention; Figure 2 A schematic diagram of the formation process of mountain torrents and debris flows in high-cold areas proposed in an embodiment of the present invention; Figure 3 A schematic diagram of the dynamic update of snow simulation deviation and remote sensing products in alpine areas proposed in an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of a system for calculating debris flow in alpine areas proposed in an embodiment of the present invention. DETAILED DESCRIPTION

[0023] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0024] Those skilled in the art will understand that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as generally understood by those skilled in the art in the art to which the present invention belongs. It should also be understood that terms such as those defined in general dictionaries should be understood to have meanings consistent with the meanings in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless specifically defined.

[0025] Figure 1 FIG. 1 is a flow chart of a method for calculating debris flow in a high-cold region according to an embodiment of the present invention. Figure 1 As shown, including: Step S101: obtaining meteorological data including surface temperature and hourly precipitation of a monitoring station in a high-cold area, and obtaining snowfall and rainfall based on the meteorological data; In one embodiment of the present invention, obtaining snowfall and rainfall based on the meteorological data includes: Calculating the conditional frequency of snowfall using a hyperbolic tangent function and the surface air temperature in the meteorological data; The snowfall amount and rainfall amount at the monitoring station in the high-cold area are calculated respectively by using the conditional frequency of snowfall and the hourly precipitation in the meteorological data.

[0026] Step S102: Based on the meteorological data, the snowfall and the rainfall, respectively calculating the snow runoff data, the runoff data generated by glacier melting, the debris flow gully flow data driven by rainfall and the groundwater flow data of the monitoring station in the high-cold area; In one embodiment of the present invention, calculating the snow runoff data of the high-cold area monitoring station based on the meteorological data, the snowfall and the rainfall includes: Calculating the potential snowmelt at the current moment based on the degree-time factor model and the surface air temperature in the meteorological data, and calculating the actual snowmelt at the current moment based on the potential snowmelt at the current moment; Calculate the snow reserve at the current moment based on the surface air temperature in the meteorological data, the snowfall amount and the actual snowmelt amount at the current moment; Calculate the amount of meltwater in the snow layer at the current moment based on the surface air temperature in the meteorological data, the rainfall and the snow reserve at the current moment; Based on the surface air temperature in the meteorological data, the rainfall, the actual snowmelt amount at the current moment and the meltwater amount in the snow layer at the current moment, the snow runoff data at the high-cold area monitoring station at the current moment is calculated.

[0027] In one embodiment of the present invention, based on the meteorological data, the snowfall and the rainfall, calculating the runoff data generated by the melting of glaciers at the high-cold area monitoring station includes: Based on the degree-time factor model and the surface air temperature in the meteorological data, the melting amount of the glacier without rock cover and the melting amount of the glacier with rock cover are calculated respectively; Calculating total glacier melt based on the melt of the glacier without debris cover and the melt of the glacier with debris cover; Based on the total glacier melt volume and the configured glacier runoff coefficient, the runoff data generated by the glacier melt at the alpine area monitoring station is calculated.

[0028] In one embodiment of the present invention, based on the meteorological data, the snowfall and the rainfall, calculating the rainfall-driven debris flow gully flow data at the high-cold area monitoring station includes: Based on the debris flow erosion intensity and debris flow runoff equation of the monitoring station in the alpine region, the runoff height, runoff velocity and runoff depth of the debris flow are obtained; Based on the runoff height, runoff velocity and runoff depth of the debris flow movement, the rainfall-driven debris flow gully mouth flow data of the alpine region monitoring station is calculated.

[0029] In one embodiment of the present invention, calculating the groundwater flow data of the high-cold area monitoring station based on the meteorological data, the snowfall and the rainfall includes: The groundwater depth and soil characteristics of the monitoring station in the alpine region, and based on the groundwater depth and soil characteristics, calculating the groundwater recharge at the current moment; Based on the groundwater recharge at the current moment, the groundwater flow rate flowing into the main river channel at the high-cold area monitoring station at the current moment is calculated.

[0030] Step S103: Calculate the total runoff data of the debris flow at the monitoring station in the alpine region based on the snow runoff data, the runoff data generated by glacier melting, the debris flow gully flow data driven by rainfall, and the groundwater flow data at the monitoring station in the alpine region.

[0031] In one embodiment of the present invention, based on the snow runoff data, glacier melt runoff data, rainfall-driven debris flow gully flow data, and groundwater flow data of the monitoring station in the alpine region, the total runoff data of the debris flow at the monitoring station in the alpine region is calculated, which includes: By processing the snow runoff data, the runoff data generated by glacier melting, the debris flow gully flow data driven by rainfall, and the groundwater flow data, the total runoff data of the debris flow at the high-cold area monitoring station is obtained.

[0032] The present invention provides a method for calculating debris flow in alpine areas, which can not only couple the dynamic changes of snow accumulation, but also take into account the dynamic characteristics of debris flow, so as to better simulate and predict the peak flow and disaster process triggered by "rain, snow (ice) mixing". By incorporating multi-source remote sensing correction into the snowmelt calculation of the hydrological model and coupling the snow and ice flow generation with the debris flow model, it can make up for the deficiency of the existing debris flow model being limited to rainfall drive, and provide more scientific and effective technical support for the prevention and emergency management of debris flow disasters in alpine areas with insufficient data.

[0033] The present invention provides a method for calculating debris flow in high-cold areas taking into account the dynamic changes of snow accumulation. Figure 2 As shown, it mainly includes: (001) Calculation method of snowmelt and icemelt based on hydrological process With reference to the degree-day method in the hydrological model, the snowmelt and icemelt mechanism based on the degree-time factor was improved, and the snow and glacier melting process in the alpine areas was numerically simulated. Meteorological elements (temperature, precipitation, etc.) and spatial factors (topography, slope aspect, etc.) were integrated into the model to obtain the snow / ice melting water yield in the alpine areas at different time steps.

[0034] (002) Coupled debris flow dynamics model The debris flow source, rheological characteristics and channel hydrodynamics are coupled to the calculation results of snowmelt and icemelt flow generation to form a comprehensive model integrating "solid-liquid coupling rheology-flow generation and convergence"; By considering the debris flow initiation conditions (critical flow velocity, shear stress, etc.) and the material supply process, the formation, flow and peak flow evolution of debris flow are simulated.

[0035] (003) Use dynamically updated snow cover products Using the hourly / daily snow cover area (SCA) products fused from remote sensing and ground observations, the snow process in the model calculation can be “dynamically replaced” or “online corrected”; like Figure 3 As shown, at each time step or specified period, the actual remote sensing snow distribution is directly or partially (weighted fusion) applied to the model snow storage / snow cover update, thereby more accurately reflecting the actual distribution and ablation of snow.

[0036] (004) Improve the applicability under conditions where snowmelt, icemelt and rainfall coexist Fully consider the impact of mixed supply of "rain + snow (ice)" on debris flow generation and peak flow, breaking through the limitations of traditional single rainfall trigger or single snowmelt trigger; By coupling multi-source data, the ability to characterize complex hydrological processes in high-altitude cold areas is improved, making the model more robust when facing drastic temperature changes, ice and snow melting, and heavy rain.

[0037] (005) Improve the accuracy of debris flow simulation Improve the simulation accuracy of debris flow hydrodynamics and peak flow through systematic integration of snowmelt runoff, ice melt recharge and rain-generated runoff, and based on dynamically corrected snow cover information; Ultimately, more reliable prediction and risk assessment of debris flow processes in high-altitude and cold regions can be achieved, which can be used for decision-making support in multiple fields such as disaster warning, engineering protection, and regional planning.

[0038] Based on the existing hydrological model for snow / ice melting, this method uses snow and ice melting calculation + dynamic snow cover correction + debris flow dynamics coupling to more accurately simulate the debris flow process in high-altitude cold areas under the triple supply of "rain, snow, and ice", significantly improving the prediction accuracy of debris flow peak flow and evolution. This integrated and dynamically updated numerical simulation scheme will effectively fill the technical gap in the study of debris flow triggered by rain and snow in high-altitude cold areas, and has high application value and promotion potential.

[0039] The following is a detailed description of each step of the embodiment of the present invention. Step 1: Rainfall segmentation The present invention uses a hyperbolic tangent function to estimate the snowfall at a grid point, and the conditional frequency of snowfall can be calculated by the following formula: ; In the formula, T avg,t is the surface air temperature at hour t (unit: ℃); the specific coefficients a, b, c and d of the hyperbolic tangent function are obtained by least squares estimation fitting of the observed data of the Qinghai-Tibet Plateau and surrounding mountainous areas, which are −49.02, 0.4321, 2.47 and 1, respectively.

[0040] Therefore, the snowfall in hour t ( Prcp s,t ,mm hour -1 ) / Rainfall ( Prcp r,t ,mm hour -1 ) can be obtained by hourly precipitation ( Prcp ,mm hour -1 ) multiplied by the snowfall condition frequency F or (1-F).

[0041] ; Step 2: Calculation of snowmelt runoff at the gully mouth Snow Melt To simulate snowmelt, the mature and widely used degree-hour factor modeling (DHF) method was adopted. With reference to the widely used degree-day factor in cryosphere models, the degree-hour factor model is based on the empirical relationship between snowmelt and temperature. Compared with the energy balance model, the degree-hour factor model is easier to construct and only requires temperature, a meteorological element that is generally available and easy to interpolate. Based on the degree-hour factor method, the hourly potential snowmelt is calculated by the following formula: ; In the formula, SM pot,t (Unit: mm hour -1 ) is the potential snowmelt at hour t, DHF s(Unit: mm ℃ -1 hour -1 ) is the degree-time factor for the rate of change of regional snow cover.

[0042] The actual amount of snowmelt is limited by the amount of snow at the end of the previous hour, and the calculation formula is: ; In the formula, SM act (Unit: mm hour -1 ) is the actual snowmelt amount at hour t, SM t-1 is the snow accumulation at hour t-1. Then, according to the actual snowmelt SM act,t and snowfall Prcp s,t , update the snow storage at the end of hour t-1 to the current hour t. Consider that part of the actual snowmelt will refreeze in the snow layer and will not form runoff immediately. When the temperature is below freezing, the meltwater frozen in the snow layer at hour t-1 will be re-included in the snow storage at hour t. The calculation formula is: ; In the formula, SWE t is the snow reserve at hour t, SWE t-1 is the snow accumulation at hour t-1, Prcp s,t is the solid precipitation in hour t, SM act,t is the actual snowmelt amount at hour t, FSWE t-1 is the amount of meltwater frozen in the snow layer at hour t-1; all the above quantities are in mm.

[0043] Dynamic update of remote sensing snow products Considering the large deviation in snow simulation, the remote sensing snow area product ( SCA obs , which is the same value for 24 hours a day) replaces the result of the snow calculation in the previous hour, that is, the current snow area product of the grid and the grid calculation are both in the snowy state ( SWE >0 mm), the calculation process remains unchanged. If there is a deviation between the calculation result and the remote sensing observation, the remote sensing observation shall prevail for subsequent calculations. All grid points with SWE>0 in the calculation are the simulated snow area of ​​the basin ( SCA model ).

[0044] ; When there are observations: directly cover the model results, so that the final snow cover ratio at hour t ( SCA model,t ) is consistent with remote sensing ( SCA obs,t ); when there is no observation: the model maintains the original SCA model,t value or fill it in through other interpolation methods. The model then uses SCA final,t Whether the final snow cover of a single grid point in that hour is snow covered or the "initial snow cover" information of the next hour t+1.

[0045] like Figure 3 As shown, once the replacement / fusion is completed, we get SCA final,t After that, the model will use it as the initial snow cover information before the start of hour t+1: ; Snow and frozen To describe the ability of the snow layer to refreeze the snowmelt water, a calibrated water storage capacity ( WSWE ,Unit: mm·mm -1 ), represents the total amount of meltwater that can be frozen per mm of snow equivalent in the snow reserve (mm). Therefore, the maximum amount of meltwater that can be frozen in the snow layer ( FSWE max ,mm) is limited by the amount of snow: ; The amount of meltwater stored in the snow layer that could potentially freeze in the next period of time can then be calculated. FSWE t : ; In the formula, FSWE t is the amount of meltwater in the snow layer at hour t, FSWE max , t is the maximum amount of meltwater that can be frozen in the snow layer at hour t, FSWE t-1 is the amount of meltwater frozen in the snow layer at hour t-1, Prcp r,t is the rainfall in hour t, SM act,t is the actual snowmelt amount at hour t; all items are in mm.

[0046] Snow runoff calculation Total snow reserves ( SWE all,t , mm) is composed of snow reserves and freezable meltwater in the snow layer and can be expressed as: ; In the formula, 1- F glac (dimensionless) represents the proportion of non-glacier covered watershed grid cells. In this paper, it is assumed that snow accumulation and snowmelt only occur on the grid cell area considered as land; while snowfall on glaciers is simulated by the glacier module.

[0047] Runoff from the snowpack occurs when the air temperature is above freezing and no more meltwater can be frozen in the snow. R sm , mm hour -1 ). Its calculation formula is: ; In the formula, Δ FSWE (Unit: mm) is the change in meltwater storage in the snow layer, defined as: ; Step 3: Glacial runoff at the mouth of the gully Since debris flow dynamics models are usually run at a spatial resolution of meters, glacier dynamic processes such as ice flow cannot be explicitly resolved in the model. Therefore, in this invention, glaciers are considered as "surface melt" that can be fully or partially covered on the grid cells.

[0048] Melting glaciers Glacier melt is also calculated using the degree-time factor modeling approach. Because the melting rates of glaciers covered with debris differ from those without, the model uses different degree-time factors for each type of glacier. GM DF (Unit: mm) Calculation is as follows: ; In the formula, DHF DF (Unit: mm ℃ -1 hour -1 ) is the time factor calibrated for glaciers without debris cover, F DF (dimensionless) is the ratio of the glacier cover to the rock-free glacier in the grid cell ( F glac ) is the proportion of .

[0049] Hourly melt of glaciers covered with debris GM DC (mm) is calculated in a similar manner, but using a different time factor: ; In the formula, DHF DC (Unit: mm ℃ -1 hour -1 ) is the time factor for a glacier covered with debris, F DC (dimensionless) is the proportion of glaciers covered with gravel in the grid cell within the glacier cover ratio.

[0050] Total glacier melt in grid cells GM all (mm) is obtained by summing the melt of glaciers without debris cover and glaciers with debris cover, multiplied by the glacier cover ratio.

[0051] ; Glacial runoff In the present invention, part of the glacier meltwater will infiltrate and replenish groundwater, while the rest will form runoff. The distribution of these two parts is determined by a glacier melt runoff coefficient ( RC glac , dimensionless), with a value range of 0 to 1. As a result, the runoff generated by glacier melt R GM (mm, mm hour -1 ) can be expressed as: ; Glacial seepage Glacier meltwater infiltration replenishes groundwater ( GM perc ,mm hour -1 ) is defined as: ; The infiltrating glacial meltwater will merge with the infiltrating soil layer in the non-glaciated area of ​​the grid unit and eventually recharge the groundwater.

[0052] Step 4: Debris flow movement process Vegetation interception The empirical formula considering vegetation cover interception can be expressed as: ; in: I c represents the total vegetation interception; Prcp r,t represents the total rainfall; k = 0.046; ·LAI stands for correction factor; LAI is the leaf area index; S max Represents the maximum vegetation canopy storage.

[0053] ; Rainfall Infiltration The Richard equation, which is expressed as coupled variables of water content and matrix suction, is used to describe the soil infiltration process under rainfall conditions: ; Where: t Represents time, i Represents the soil moisture content, ψ represents the internal pressure head of the soil, z represents the soil thickness, K s represents the soil permeability coefficient, S v Represents the water absorption caused by the vegetation roots. Considering the disturbance of the bottom boundary to the infiltration process during the rainwater infiltration process, two different boundary conditions (the first type DirichletBC boundary and the second type NeumannBC boundary) are used to describe it. ; Where: i s represents the saturated soil moisture content, i m represents the initial soil moisture content, I t represents the infiltration intensity, −D( i ) represents the diffusion coefficient, ∇ i represents the gradient of the field variable, K( i ) represents the convection or transport term.

[0054] Channel instability The slope stability calculation equation considering rainfall infiltration conditions can be expressed as follows: ; Where: F s represents the slope stability coefficient, z H represents the soil thickness, c Represents the effective cohesion of the soil, f represents the internal friction angle of the slope, G Represents soil weight, s represents the soil suction stress, p w represents the pore water pressure, c s represents the dry density of soil, c w represents the wet density of soil, x Represents the suction stress coefficient.

[0055] Slope catchment The shallow-water equation is used to describe the slope runoff process under rainfall conditions: ; Where: h represents the depth of overland flow, (x, y) represents the direction of overland flow, Prcp r,t represents the rainfall intensity, I t represents the soil saturated infiltration intensity, g represents the acceleration due to gravity, (u, v) represents the speed of overland flow, z b represents the surface elevation, (S fx , S fy ) Represents the friction resistance encountered by slope confluence.

[0056] Debris flow movement The influence of source erosion on debris flow movement is considered on the basis of the traditional Savage-Hutter equation, which can be described as: ; Where: h s represents the thickness of the debris flow, (x, y) Represents the direction of debris flow movement. E represents the intensity of debris flow erosion, g represents the acceleration due to gravity, (u, v) represents the speed of debris flow, (u b , v b ) represents the velocity of debris flow at the critical channel interface, z b represents the surface elevation, (S gx , S gy ) represents the friction resistance at the bottom of the debris flow, c represents the solid phase volume fraction of debris flow, p Represents the saturation of eroded material.

[0057] Rainfall-driven debris flow gully discharge ( R rain,t ,mm hour -1 ) can be expressed as: ; Where: dx Represents the cross-sectional area of ​​the ditch mouth.

[0058] Step 5: Base flow recharge at the gully mouth Infiltration of glacier meltwater contributes to groundwater recharge. Groundwater recharge does not usually occur instantaneously, but with a certain time lag, depending on the groundwater depth and soil properties. It is calculated as: ; In the formula, G chrg,t (mm) and G chrg,t-1 (mm) represent the groundwater recharge at time t and time t-1 respectively, i gw (hours) is the lag time constant, w 2,percw (mm) is the amount of water that seeps from the second soil layer into the third soil layer at time t.

[0059] ; In the formula, R BF,t (mm) and R BF,t-1 is the groundwater flow into the main river channel at the current time and at time t-1, K sat (mmhour -1 ) is the hydraulic conductivity of the shallow aquifer, ε (dimensionless) is the water supply degree of the shallow aquifer, L gw (m) is the hydrological distance from the sub-basin watershed to the main river channel, G chrg (mm) is the groundwater recharge entering the shallow aquifer at the current moment, β gw (dimensionless) is the bottom flow attenuation coefficient, SW 3 is the third layer of soil moisture, BF thresh is the groundwater flow threshold into the main river channel.

[0060] Step 6: Calculation of total runoff at the gully mouth Assume that at time t (or time step), the total runoff or total outflow generated ( R total,t , mm hour -1 ) is composed of snowmelt, icemelt, rainfall runoff and groundwater recharge. ; For the method embodiments, for the sake of simplicity, they are all described as a series of action combinations, but those skilled in the art should know that the embodiments of the present invention are not limited by the order of the actions described, because according to the embodiments of the present invention, some steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all preferred embodiments, and the actions involved are not necessarily required by the embodiments of the present invention.

[0061] Figure 4 The schematic diagram of the structure of a system for calculating debris flow in high-cold areas proposed in an embodiment of the present invention is as follows: Figure 4 As shown, including: An acquisition module is used to acquire meteorological data including surface air temperature and hourly precipitation at monitoring stations in high-cold areas, and obtain snowfall and rainfall based on the meteorological data; A first calculation module is used to calculate the snow runoff data, the runoff data generated by glacier melting, the debris flow gully flow data driven by rainfall, and the groundwater flow data of the monitoring station in the high-cold area based on the meteorological data, the snowfall, and the rainfall; The second calculation module is used to calculate the total runoff data of the debris flow at the monitoring station in the high-cold area based on the snow runoff data, the runoff data generated by glacier melting, the debris flow gully flow data driven by rainfall and the groundwater flow data at the monitoring station in the high-cold area.

[0062] In one embodiment of the present invention, the acquisition module is specifically used to calculate the conditional frequency of snowfall using the hyperbolic tangent function and the surface air temperature in the meteorological data; and to calculate the snowfall and rainfall at the high-cold area monitoring station using the conditional frequency of snowfall and the hourly precipitation in the meteorological data.

[0063] Another aspect of the present invention provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor; when the computer program is executed by the processor, the steps of the method for calculating the flow rate of debris flow in high-cold areas are implemented. Figure 1 Alternatively, when the processor executes the computer program, the functions of each module in the above-mentioned device for calculating debris flow in alpine regions are realized, for example Figure 4 The acquisition module, the first calculation module, and the second calculation module are shown.

[0064] During the specific implementation process of the system embodiment and the device embodiment, reference may be made to the above method embodiment and corresponding technical effects may be achieved.

[0065] In addition, those skilled in the art will appreciate that, although some embodiments herein include certain features included in other embodiments but not other features, the combination of features of different embodiments is meant to be within the scope of the present invention and form different embodiments. For example, any one of the claimed embodiments may be used in any combination.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments can still be used to modify the technical solutions or to perform equivalent replacements on some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for calculating debris flow in alpine areas, characterized in that: include: Obtaining meteorological data including surface air temperature and hourly precipitation from monitoring stations in high-cold areas, and obtaining snowfall and rainfall based on the meteorological data; Based on the meteorological data, the snowfall and the rainfall, respectively calculate the snow runoff data, the runoff data generated by glacier melting, the debris flow gully flow data driven by rainfall and the groundwater flow data of the monitoring station in the alpine region; The total runoff data of debris flow at the monitoring station in the alpine area is calculated based on the snow runoff data, the runoff data generated by glacier melting, the debris flow gully flow data driven by rainfall, and the groundwater flow data at the monitoring station in the alpine area.

2. The method according to claim 1, characterized in that: The snowfall and rainfall amounts obtained based on the meteorological data include: Calculating the conditional frequency of snowfall using a hyperbolic tangent function and the surface air temperature in the meteorological data; The snowfall amount and rainfall amount at the monitoring station in the high-cold area are calculated respectively by using the conditional frequency of snowfall and the hourly precipitation in the meteorological data.

3. The method according to claim 2, characterized in that Calculating the snow runoff data of the high-cold area monitoring station based on the meteorological data, the snowfall and the rainfall includes: Calculating the potential snowmelt at the current moment based on the degree-time factor model and the surface air temperature in the meteorological data, and calculating the actual snowmelt at the current moment based on the potential snowmelt at the current moment; Calculate the snow reserve at the current moment based on the surface air temperature in the meteorological data, the snowfall amount and the actual snowmelt amount at the current moment; Calculate the amount of meltwater in the snow layer at the current moment based on the surface air temperature in the meteorological data, the rainfall and the snow reserve at the current moment; Based on the surface air temperature in the meteorological data, the rainfall, the actual snowmelt amount at the current moment and the meltwater amount in the snow layer at the current moment, the snow runoff data at the high-cold area monitoring station at the current moment is calculated.

4. The method according to claim 3, characterized in that: Calculating the runoff data generated by glacier melting at the alpine region monitoring station based on the meteorological data, the snowfall and the rainfall includes: Based on the degree-time factor model and the surface air temperature in the meteorological data, the melting amount of the glacier without rock cover and the melting amount of the glacier with rock cover are calculated respectively; Calculating total glacier melt based on the melt of the glacier without debris cover and the melt of the glacier with debris cover; Based on the total glacier melt volume and the configured glacier runoff coefficient, the runoff data generated by the glacier melt at the alpine area monitoring station is calculated.

5. The method according to claim 4, characterized in that Calculating the rainfall-driven debris flow gully mouth flow data at the high-cold area monitoring station based on the meteorological data, the snowfall and the rainfall includes: Based on the debris flow erosion intensity and debris flow runoff equation of the monitoring station in the alpine region, the runoff height, runoff velocity and runoff depth of the debris flow are obtained; Based on the runoff height, runoff velocity and runoff depth of the debris flow movement, the rainfall-driven debris flow gully mouth flow data of the alpine region monitoring station is calculated.

6. The method according to claim 5, characterized in that Calculating the groundwater flow data of the monitoring station in the high-cold area based on the meteorological data, the snowfall and the rainfall includes: The groundwater depth and soil characteristics of the monitoring station in the alpine region, and based on the groundwater depth and soil characteristics, calculating the groundwater recharge at the current moment; Based on the groundwater recharge at the current moment, the groundwater flow rate flowing into the main river channel at the high-cold area monitoring station at the current moment is calculated.

7. The method according to claim 6, characterized in that Based on the snow runoff data, glacier melt runoff data, rainfall-driven debris flow gully flow data and groundwater flow data at the monitoring station in the alpine region, the total runoff data of debris flow at the monitoring station in the alpine region is calculated, including: By processing the snow runoff data, the runoff data generated by glacier melting, the debris flow gully flow data driven by rainfall, and the groundwater flow data, the total runoff data of the debris flow at the high-cold area monitoring station is obtained.

8. A system for calculating debris flow in high-cold areas, characterized in that: The system is used to execute the method according to any one of claims 1 to 7, and the system comprises: An acquisition module is used to acquire meteorological data including surface air temperature and hourly precipitation at monitoring stations in high-cold areas, and obtain snowfall and rainfall based on the meteorological data; A first calculation module is used to calculate the snow runoff data, the runoff data generated by glacier melting, the debris flow gully flow data driven by rainfall, and the groundwater flow data of the monitoring station in the high-cold area based on the meteorological data, the snowfall, and the rainfall; The second calculation module is used to calculate the total runoff data of the debris flow at the monitoring station in the high-cold area based on the snow runoff data, the runoff data generated by glacier melting, the debris flow gully flow data driven by rainfall and the groundwater flow data at the monitoring station in the high-cold area.

9. The system according to claim 8, characterized in that The acquisition module is specifically used to calculate the conditional frequency of snowfall using the hyperbolic tangent function and the surface air temperature in the meteorological data; and to calculate the snowfall and rainfall at the high-cold area monitoring station using the conditional frequency of snowfall and the hourly precipitation in the meteorological data.

10. An electronic device, characterized in that: It comprises a memory, a processor and a computer program stored in the memory and executable on the processor; when the computer program is executed by the processor, the steps of the method for calculating the debris flow rate in high-cold areas described in any one of claims 1 to 7 are implemented.

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