CN115186483A - A method and system for identifying the interaction mechanism of water and soil resources - Google Patents

Abstract

The invention provides a method and a system for identifying a water and soil resource mutual feedback mechanism, which comprise the following steps: acquiring hydrological data, meteorological data, geological data and remote sensing data of a target area; according to the obtained data, carrying out energy process simulation, evaporation and heat dissipation process simulation, vertical infiltration calculation, slope runoff generation calculation, slope confluence calculation, river confluence calculation and underground water movement calculation to obtain a distributed hydrological model; meanwhile, the surface flow rate, the precipitation amount and the evaporation heat dissipation amount of the drainage basin at different time scales and the net primary productivity of different land utilization types are combined to obtain the flow rate coefficient and the ratio of the evaporation heat dissipation to the net primary productivity at different time periods in the drainage basin space; and determining the interaction law of the water and soil resources according to the current generation coefficient and the ratio of the evaporative heat dissipation to the net primary productivity. The interaction rule of water and soil resources can be accurately obtained by obtaining the hydrological model based on the simulation of multiple processes and multiple elements of the drainage basin, and technical support is provided for comprehensive treatment and water and soil resource optimal allocation of the drainage basin.

Description

A method and system for identifying the interaction mechanism of water and soil resources

technical field

The invention relates to the technical field of water cycle simulation and simulation in a river basin, in particular to a method and system for identifying the interaction mechanism of water and soil resources based on water cycle simulation in a river basin.

Background technique

The problem of human-land competition for water and human-water for land restricts the imbalance between the natural ecosystem and the socio-economic system. The scales of water resources management and land resource management objects are inconsistent, and it is difficult to understand the water production and consumption on land patches. processes and their ecological effects. Watershed hydrological simulation has always been a research method in the field of hydrology and water resources. Hydrological simulation can quantify the hydrological process and quantitatively describe the time-varying process and spatial distribution of each hydrological cycle element under different land use types. . In order to better study the law of hydrological change and the interaction of water and soil resources, it is necessary to further strengthen the simulation function of the watershed hydrological model, including process refinement and improvement of simulation equations.

At present, domestic and foreign hydrologists have made a lot of research and contributions in this area, including a variety of model software such as surface hydrological process simulation, groundwater movement simulation, river movement model, and urban stormwater simulation. However, from the perspective of the whole basin, from the surface to the underground, from the slope to the river, there are few hydrological models that consider the simulation of all-element hydrological processes. Aiming at the above deficiencies, a method for identifying the interaction mechanism of water and soil resources based on water cycle simulation in the basin is provided.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a method and system for identifying the interaction mechanism of water and soil resources, which can accurately know the interaction mechanism of water and soil resources based on the refined simulation model of the watershed considering the multi-process and multi-element of hydrology, expand the technical means of watershed hydrology research, and provide the basis for the watershed. Provide technical support for comprehensive management and optimal allocation of water and soil resources.

For achieving the above object, the present invention provides the following scheme:

A method and system for identifying the interaction mechanism of water and soil resources, comprising:

Obtain hydrological data, meteorological data, geological data and remote sensing data of the target area;

According to the hydrological data, the meteorological data, the geological data and the remote sensing data, energy process simulation, evaporative heat dissipation process simulation, vertical infiltration calculation, slope runoff calculation, slope confluence calculation and river confluence calculation and Groundwater movement calculation to obtain a distributed hydrological model; the energy process simulation includes long-wave radiation and short-wave radiation calculation; the evapotranspiration process simulation includes vegetation transpiration, vegetation interception evaporation, water evaporation, bare soil evaporation, urban surface evaporation and buildings evaporation;

Calculate and count the surface runoff at different time scales of the basin based on the distributed hydrological model, and combine with the precipitation to obtain the runoff coefficient at different time periods in the basin space;

Calculate and count evaporative heat dissipation at different time scales in the basin based on the distributed hydrological model and determine the ratio of evaporative heat dissipation to net primary productivity in combination with the net primary productivity of different land use types;

The interaction law of water and soil resources is determined according to the runoff coefficient and the ratio of the evaporative heat dissipation to the net primary productivity.

The present invention also provides an identification system for the interaction mechanism of water and soil resources, including:

A data acquisition module is used to acquire hydrological data, meteorological data, geological data and remote sensing data of the target area; a distributed hydrological model simulation module is used to obtain data according to the hydrological data, the meteorological data, the geological data and the remote sensing data The energy process simulation, evaporative heat dissipation process simulation, vertical infiltration calculation, slope runoff calculation, slope confluence calculation, river confluence calculation, and groundwater movement calculation are performed on the data to obtain a distributed hydrological model; the energy process simulation includes long-wave radiation and Shortwave radiation calculation; the evapotranspiration process simulation includes vegetation transpiration, vegetation interception evaporation, water evaporation, bare soil evaporation, urban surface evaporation and building evaporation;

The runoff coefficient calculation module is used to calculate and count the surface runoff at different time scales of the watershed based on the distributed hydrological model, and combine the precipitation to obtain the runoff coefficient at different time periods in the watershed space;

A module for calculating the ratio of evaporative heat dissipation to net primary productivity, which is used to calculate and count the evaporative heat dissipation at different time scales of the watershed based on the distributed hydrological model and to determine the ratio of evaporative heat dissipation to net primary productivity in combination with the net primary productivity of different land use types ;

An acquisition module for the interaction law of water and soil resources, configured to determine the interaction law of water and soil resources according to the runoff coefficient and the ratio of the evaporative heat dissipation to the net primary productivity.

According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

The invention provides a method and system for identifying the interaction mechanism of water and soil resources, comprising: acquiring hydrological data, meteorological data, geological data and remote sensing data of a target area; Infiltration calculation, slope runoff calculation, slope confluence calculation, river confluence calculation and groundwater movement calculation, a distributed hydrological model is obtained; based on the distributed hydrological model, the surface runoff at different time scales of the basin is calculated and counted and combined with precipitation to obtain the basin Runoff coefficient at different time periods in space; calculate and count evaporative heat dissipation at different time scales in the basin based on distributed hydrological model, and determine the ratio of evaporative heat dissipation to net primary productivity combined with the net primary productivity of different land use types; according to the runoff coefficient and the ratio of the evaporative heat dissipation to the net primary productivity to determine the interaction law of water and soil resources. The hydrological model based on the refined simulation of multi-process and multi-element in the watershed can accurately know the interaction law of water and soil resources, and provide technical support for comprehensive management of the watershed and optimal allocation of water and soil resources.

Description of drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings required in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some of the present invention. In the embodiments, for those of ordinary skill in the art, other drawings can also be obtained according to these drawings without any creative effort.

FIG. 1 is a flowchart of a method for identifying a water and soil resource interaction mechanism provided in Embodiment 1 of the present invention;

Fig. 2 is the hydrological analysis process of the Sihe River Basin provided by the embodiment of the present invention 1;

Fig. 3 is the topography data of the Sihe River Basin provided by Embodiment 1 of the present invention;

Fig. 4 is the meteorological data of the Sihe River Basin provided by Embodiment 1 of the present invention;

Fig. 5 is the mutation test of the Sihe River Basin provided by the embodiment of the present invention 1;

Fig. 6 is the vertical and horizontal structure of the watershed hydrological model provided in Embodiment 1 of the present invention;

7 is the calibration and verification of the Sihe River Basin provided by Embodiment 1 of the present invention;

8 is the spatial distribution of the runoff coefficient in the Sihe River Basin provided by Embodiment 1 of the present invention;

Fig. 9 is the NPP/ET spatial distribution of Sihe River Basin provided by Embodiment 1 of the present invention;

10 is a schematic diagram of the water balance in the grid provided in Embodiment 1 of the present invention;

11 is a schematic diagram of the dissection of the aquifer system provided in Embodiment 1 of the present invention;

12 is the three-dimensional positional relationship between the peripheral grid and the central grid provided in Embodiment 1 of the present invention;

FIG. 13 is the plane positional relationship between the peripheral grid and the central grid according to Embodiment 1 of the present invention.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

The purpose of the present invention is to provide a method and system for identifying the interaction mechanism of water and soil resources, which can accurately know the interaction mechanism of water and soil resources based on the refined simulation model of the watershed considering the multi-process and multi-element of hydrology, expand the technical means of watershed hydrology research, and provide the basis for the watershed. Provide technical support for comprehensive management and optimal allocation of water and soil resources.

In order to make the above objects, features and advantages of the present invention more clearly understood, the present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.

Example 1

As shown in FIG. 1 , this embodiment provides a method and system for identifying the interaction mechanism of water and soil resources, including:

First, a general summary of the scheme of this embodiment is made: the Sihe River Basin is taken as an example to illustrate the refined simulation method of the basin based on the coupled distributed hydrological model and the groundwater model provided by this embodiment:

(1) Model input data preparation.

Its specific performance is:

First, basin hydrological analysis, based on DEM, uses the hydrological analysis tools in ArcGIS to perform subsidence calculation, flow direction calculation, confluence accumulation calculation, and basin generation. The basin boundary at this time is used as the boundary for later input data preparation, such as As shown in Figure 2;

Next, prepare the topography data. The watershed range generated in the previous step is the boundary file, cut the DEM, soil type data, soil thickness data, land use type data of each period, and river network data, and convert all the above cut files into ASCII files as Input file, as shown in Figure 3;

Third, to prepare the meteorological data, select the weather stations and rainfall stations in and around the watershed and number them sequentially, and draw the Thiessen polygons of the weather stations and rainfall stations with the help of the Create Thiessen Polygons tool in ArcGIS. Convert the drawn Thiessen polygon to a raster file according to the station serial number with the watershed range as the boundary, and convert it to an ASCII file. Extract the required meteorological data and precipitation data, and prepare a TXT file according to the format of "year-month-month-1st station-2nd station-...nth station", as shown in Figure 4;

Finally, prepare other basic data and parameters, such as weather station latitude, elevation, rate of change of precipitation with elevation, monthly vegetation coverage data, monthly leaf area index data, surface reflectance of various land uses to shortwave radiation, various soil types Saturated water content, field water holding capacity of various soils, withering coefficients of various soils, sag reserves of various land use types, lateral-vertical-vertical permeability coefficients of each soil layer, slope Manning coefficient, river Manning Ning coefficient.

(2) Model simulation calculation.

Energy process simulation, including long-wave radiation and short-wave radiation calculation of different underlying surfaces; evapotranspiration process simulation, including vegetation transpiration (Penman-Monteith), vegetation interception evaporation (Penman), water evaporation (Penman), bare soil evaporation (corrected Penman), urban surface evaporation and building evaporation (Penman); vertical infiltration calculation (Green-Ampt); slope runoff calculation, including hyperosmotic runoff (Houghton slope runoff) and full storage runoff (saturated slope Surface runoff); slope confluence calculation (kinematic wave) and river confluence calculation (kinematic wave); groundwater movement calculation (Darcy formula), the vertical and horizontal structure of each element process of the hydrological cycle simulation is shown in Figure 5.

(3) Model calibration and verification.

First, the mutation point test, using the Mann-Kendall method to perform mutation test on the rainfall data, before the mutation point as the rate period, after the mutation point as the verification period, as shown in Figure 6;

Secondly, the model is calibrated, various parameters are debugged, and the simulation effect of the model is judged by three indicators of correlation coefficient, Nash coefficient and relative error.

Model verification, on the basis of model calibration, fixed parameters, and then periodically simulated and verified the ratio. If the three indicators passed, the model verification passed. The model calibration and verification results are shown in Figure 7.

(4) Research on the interaction mechanism of water and soil resources.

First, use the above compiled and debugged distributed hydrological model to calculate and count the surface runoff and precipitation at different time scales of each grid in the basin, and then obtain the runoff coefficients at different time periods in the basin space, as shown in Figure 8;

Secondly, use the distributed hydrological model compiled and debugged above to calculate and count the evapotranspiration of each grid at different time scales in the watershed, and use the net primary productivity quota of different land use types and the spatial distribution of land use to obtain the net primary productivity in the watershed. Finally, the spatial distribution of NPP and ET is compared to obtain the spatial distribution of NPP/ET at different time scales, as shown in Figure 9;

Finally, the runoff coefficient is used as an index to study the impact of land resources on water resources, and NPP/ET is used as an index to study the impact of water resources on land resources. The results of the aforementioned runoff coefficient and NPP/ET are analyzed. The interaction of water and soil resources is analyzed from the perspective.

The more detailed steps of the method described in this embodiment are carried out below:

Step S1: obtaining hydrological data, meteorological data, geological data and remote sensing data of the target area;

Wherein, step S1 specifically includes:

Step S11: basin hydrological analysis, based on DEM, with the help of hydrological analysis tools in ArcGIS, to perform sag filling calculation, flow direction calculation, confluence accumulation calculation, and basin generation, and use the basin boundary at this time as the boundary for later input data preparation;

Step S12: Prepare the topography and landform data, take the watershed range generated in step S11 as the boundary file, cut the DEM again, and use it as the watershed elevation data, cut the soil type data, soil thickness data, land use type data of each period, and river network data, and the above All cut files are converted to ASCII files as input files;

Step S13: Select the weather stations and rainfall stations within the watershed range and its preset range, and sequentially number the weather stations and rainfall stations;

Step S14: draw the Thiessen polygons of the weather station and the rain gauge station by using the tool for creating Thiessen polygons;

Step S15: with the watershed range as the boundary, convert the drawn Thiessen polygon installation weather station number and rainfall station number into grid files respectively;

Step S16: extracting meteorological data and precipitation data based on the grid file;

Among them, steps S13 to S16 realize the preparation of meteorological data, select the meteorological stations and rainfall stations in and around the watershed and number them in sequence, and draw the meteorological stations and rainfall stations respectively with the help of the Create Thiessen Polygons tool (Create Thiessen Polygons) in ArcGIS The Tyson Polygon. Convert the drawn Thiessen polygon to a raster file according to the station serial number with the watershed range as the boundary, and convert it to an ASCII file. Extract the desired meteorological data and precipitation data, and prepare a TXT file according to the format of "year-month-month-1st station-2nd station-...nth station".

Step S17: Based on the grid file, obtain the latitude and elevation of the weather station, the rate of change of precipitation with elevation, the vegetation coverage data of each month, the index data of each monthly leaf area, the reflectivity of various land use surfaces to shortwave radiation, various Soil saturated water content, field water holding capacity of various soils, withering coefficients of various soils, sag reserves of various land use types, lateral-vertical-vertical permeability coefficients of each soil layer, slope Manning coefficient and river channel Manning coefficient.

Step S17 belongs to the preparation of other basic data and parameters, such as the latitude and elevation of the weather station, the rate of change of precipitation with elevation, the monthly vegetation coverage data, the monthly leaf area index data, the reflectivity of various land use surfaces to shortwave radiation, various Soil saturated moisture content, field water holding capacity of various soils, withering coefficients of various soils, sag reserves of various land use types, lateral-vertical-vertical permeability coefficients of each soil layer, slope Manning coefficient, river channel Manning coefficient.

Step S2: Perform energy process simulation, evaporation process simulation, vertical infiltration calculation, slope runoff calculation, slope confluence calculation and river confluence according to the hydrological data, the meteorological data, the geological data and the remote sensing data calculation and groundwater movement calculation to obtain a distributed hydrological model; the energy process simulation includes long-wave radiation and short-wave radiation calculation; the evapotranspiration process simulation includes vegetation transpiration, vegetation interception evaporation, water evaporation, bare soil evaporation, urban surface evaporation and Evaporation of buildings; calculation of runoff on slopes, including hyperosmosis runoff and full storage runoff. Here, the well-known Penman formula is used for the evaporation calculation, and the well-known Penman-Montis formula is used for the transpiration.

Step S2 specifically includes:

Step S21: classifying the underlying surface types in a refined manner according to the national standard "Land Utilization Status Classification"; the refined classification means dividing the underlying surface types into a preset number of classifications;

Among them, step S21 is a refined simulation, and the underlying surface types are refined into 25 categories according to the national standard "Land Use Status Classification", each grid corresponds to a land use type, and has an independent vertical hydrological cycle process. The 25 types of underlying surfaces here can be changed, increased or decreased, and adjusted according to the simulation needs.

Step S22: for each underlying surface, calculate the long-wave radiation and the short-wave radiation to simulate the energy process;

Simulation of energy processes, including calculation of long-wave radiation and short-wave radiation of different underlying surfaces.

Step S23: simulate the evaporation and heat dissipation process according to the evaporation of vegetation, the evaporation of vegetation interception, the evaporation of water, the evaporation of bare soil, the evaporation of urban landmarks and the evaporation of buildings;

Evapotranspiration process simulation, including vegetation transpiration, vegetation interception evaporation, water evaporation, bare soil evaporation, urban surface evaporation and building evaporation.

Step S24: Calculate the variation of soil water and groundwater according to infiltration and evaporation; that is, perform vertical infiltration calculation and slope runoff calculation in the process of calculating the variation of soil water and groundwater;

Specifically, step S24 specifically includes:

Obtain the net rainfall that enters the soil through interception and depression;

Obtaining the first amount of water infiltrating the groundwater from the net rainfall of the soil;

Obtain the second amount of water evaporated back to the atmosphere and the third amount of water evaporated to the atmosphere by vegetation;

Obtain the fourth amount of water that is ultimately retained in the soil;

According to the net rainfall of the soil, the first water volume, the second water volume, the third water volume and the fourth water volume, the exchange process of the surface and groundwater volume is determined, and then the vertical infiltration calculation is realized.

The surface and groundwater are exchanged, and the precipitation enters the soil through interception and filling. Part of the water in the soil infiltrates to recharge the groundwater, part of the water evaporates and returns to the atmosphere, part of it evaporates to the atmosphere through vegetation, and part of it remains in the soil. The calculation formula is as follows:

P _n =PW _r -H (S24-1)

W _g =W ₀ +W _i -W _s -W _e (S24-3)

In the formula: P is the rainfall (mm); P _n is the net rainfall (mm), that is, the runoff; W _r is the vegetation interception (mm); H is the depression storage (mm); f is the infiltration capacity ( mm/t); W ₀ is initial soil water content (mm); Wi is soil infiltration (mm) _{; W s is} soil saturated water content (mm); We _e is evaporation (mm); W _g is The recharge amount of rainfall to groundwater (mm); Q is the lateral inflow (m ³ /t); A is the area of the recharge area (m ² ); △t is the time interval (t); S is the water storage rate (1/ m); Δh is the change in water level (m); V is the volume of groundwater control body (m ³ ).

The infiltration amount is Wi in Equation S24-2, and the flow rate is Pn in Equation S24-1.

Step S25 : use the kinematic wave model to simulate slope confluence and river confluence.

Specifically, step S25 specifically includes:

Step 1: Based on the river network and water system generated by the DEM, determine the topological relationship and calculation sequence of the slope grid and the channel grid through the accumulation of confluence and flow direction;

Step 2: Construct the water balance equation in the grid (formula S25-2) through the continuity equation (formula S25-1), and substitute the Manning formula (formula S25-3) and the channel section equation (S25-4) into the water quantity balance equation, The kinematic wave equation is digitized to obtain simulated slope confluence and simulated river confluence. This time, the river channel is generalized into a rectangular channel, and the slope confluence is generalized into a wide and shallow channel. The water balance in the grid is shown in Figure 10.

Continuity equation

water balance equation

Manning formula

Channel section equation A=b×h (formula S25-4)

In the above formula: A1 and A2 are the cross-sectional areas of the grid at the beginning and end of the grid period (m ² ); Qin is the inflow flow upstream of the grid (m3/s) (including the inflow flow Qside from the grid side, such as the slope surface The amount of water flowing into the channel from the confluence and the flow rate of the grid itself); Q1 and Q2 are the outflow water from the grid at the beginning and end of the grid period (m ³ /s), respectively; n is the Manning roughness coefficient of the grid surface; R is the The hydraulic radius of the grid channel or the wide and shallow channel on the slope (m); S ₀ is the longitudinal slope of the grid slope or channel; b is the grid width (m); h is the water depth in the grid (m).

Step S26: simulate groundwater movement according to Darcy's formula.

Step S26 specifically includes:

Meshing the groundwater simulation area;

Apply mass conservation and Darcy's formula to a single grid to get the flow between two adjacent grids;

The central grid in the grid is selected, and for each central grid, the first flow of the peripheral grid flowing into the corresponding central grid is determined according to the flow between two adjacent grids; a grid connected to a central grid, where the central grid is a grid surrounded by other grids;

calculating a second flow to the central grid from any source of the aquifer;

calculating a third flow of aquifer multisource flow to said central grid;

Determine the difference equation of each grid according to the first flow, the second flow and the third flow in combination with the continuity equation;

The water level of each grid is obtained according to the difference equation of each grid.

A more specific description of groundwater movement simulation: calculated using Darcy's formula. According to the simulation requirements, based on the aforementioned grid division method, the groundwater simulation area is divided into grids, as shown in Figure 11. The groundwater grid size is consistent with the surface water simulation grid. The thickness of underground aquifers is divided according to local actual conditions. A single grid is calculated in relation to its adjacent grids (top, bottom, left, right, front, back), as shown in Figure 12. Among them, i, j, k represent row, column, layer respectively.

Applying the principle of conservation of mass and Darcy's law to cell (i,j,k) are:

In the formula: hi _,j,k ,hi _,j-1,k are the water head values at nodes (i,j,k) and (i,j-1,k) respectively. q _i,j-1/2,k is the flow between node (i,j,k) and node (i,j-1,k); KR _i,j-1/2,k is the hydraulic conductivity ; is the cross-sectional area; is the distance between two points.

The same can be obtained:

Among them, KV, KR, and KC are an overall variable, representing the vertical, row, and column respectively, as shown in the xyx axes marked in Figure 11.

Therefore, the formula S26-2 can be written as:

Among them, CR, CC, and CV here are an overall variable, representing vertical, row, and column respectively. These three variables are an intermediate variable with no actual meaning, which is to simplify the equation. and used.

Equation S26-4 represents the flow from the adjacent six surfaces to the node (i, j, k). The flow from any source outside the aquifer to node (i, j, k) can be expressed as:

a _i,j,k,n =P _i,j,k,n +q _i,j,k,n (S26-5)

In the formula: is the external supply to this grid (m ³ /d); is the influence of the surface water cycle process on the groundwater of this grid, such as river seepage recharge, rainfall infiltration recharge (m ² /d), etc.; The impact of artificial action on the groundwater in this grid, such as pumping volume (m ³ /d).

In general, if there are N sources that affect the node (i, j, k), then the total flow from these N sources to the node (i, j, k) is:

make

Formula S26-6 can be written as:

QS _i,j,k =P _i,j,k hi _,j,k +Q _i,j,k (Formula S26-7)

According to the continuity equation, we can get:

where: is the change of water level with time (L/t); is the water storage rate (1/L) of the node (i, j, k); is the volume of the node (i, j, k) (L ³ ) .

Substituting equations S26-4 and S26-5 into equation 26-8, the finite difference equation at node (i, j, k) is obtained as follows:

Among them, S is the parameter representation after the difference, and the meaning is also the water storage rate.

Post-orientation difference method, formula S26-9 can be written as:

In the same way, the difference equation of each grid in the groundwater simulation area is obtained, and the number of grids forms the equation of the corresponding number.

Arrange the formula S26-10, put the relevant items in the formula with the groundwater level (h ^m ) at this moment on the left side of the equation, and put the groundwater level and the known items at the previous moment on the right side of the equation, as shown in formula S26 -11 shown.

make

Form a matrix: [A]×{h}={q}.

In the formula: A is the coefficient matrix; h is the water level of each grid at the moment, the variable matrix to be calculated; q is the known item matrix.

Convert the above equation into explicit format S26-13, and solve it iteratively (use the water level of the surrounding grid at time m-1 to calculate the water level of the central grid at time m, the upper limit of the number of iterations is 10, and the iteration error is 0.01m). Calculate grid (i,j) and its surrounding grids, as shown in Figure 13.

Step S3: Calculate and count the surface runoff at different time scales of the watershed based on the distributed hydrological model, and combine the precipitation to obtain the runoff coefficient at different time periods in the watershed space;

Step S4: Calculate and count evaporative heat dissipation at different time scales of the watershed based on the distributed hydrological model, and determine the ratio of evaporative heat dissipation to net primary productivity (NPP/ET) in combination with the net primary productivity of different land use types.

Calculate and count the evapotranspiration of each grid at different time scales in the basin using the distributed hydrological model compiled and debugged above, and use the net primary productivity quota of different land use types and the spatial distribution of land use to obtain the net primary productivity space in the basin Finally, the spatial NPP and ET are compared to obtain the spatial distribution of NPP/ET at different time scales.

Wherein, step S4 specifically includes:

Calculate and count evaporative heat dissipation at different time scales in the basin based on the distributed hydrological model;

Using the net primary productivity quotas of different land use types and the spatial distribution of land use to obtain the spatial distribution of net primary productivity in the basin;

The ratio between the evaporative heat dissipation and the net primary productivity in space is determined, and the spatial distribution of the ratio of the evaporative heat dissipation and the net primary productivity at different time scales is obtained.

Step S5: Determine the interaction law of water and soil resources according to the flow coefficient and the ratio of the evaporative heat dissipation to the net primary productivity.

Step S5 specifically includes:

The runoff coefficient at different time periods in the watershed space is used as an index to study the impact of land resources on water resources, and the spatial distribution of the ratio of the evaporative heat dissipation and the net primary productivity at different time scales is used as the research on the impact of water resources on water resources. It is an indicator of the impact of land resources, which analyzes the interaction of water and soil resources from the perspective of time and space.

It should be noted that after the distributed hydrological model is obtained, model calibration and verification are also included, including:

The mutation point test, using the Mann-Kendall method to perform mutation test on the rainfall data, before the mutation point as the rate period, and after the mutation point as the verification period;

Model calibration, debug various parameters, determine the simulation effect of the model through three indicators of correlation coefficient, Nash coefficient and relative error, adjust parameters until the three indicators meet the requirements, and end the parameter adjustment;

Model verification: On the basis of model calibration, the parameters are fixed, and then the ratio is regularly simulated and verified. If the three indicators pass, the model verification is passed.

In this embodiment, a hydrological model for fine simulation of a watershed from the surface to the ground, from the slope to the river is written in Python language, and it is applied to the research on the interaction of water and soil resources. Model input data preparation, including topographic data: elevation, slope, land use type, soil type and thickness, river network, meteorological data: weather station information, precipitation, temperature, wind speed, relative humidity and light time, other basic data and parameters ; Refinement simulation, with 25 types of refined underlying surfaces, each simulation unit has its own set of hydrological parameters, and performs a separate vertical hydrological simulation; model calibration and verification, by analyzing the abruptness of rainfall data, The period before the mutation point is set as the rate period, and the period after the mutation point is set as the verification period; model application, output precipitation, runoff and evapotranspiration at different times and different spatial locations in the basin; identification of the interaction of water and soil resources. It can realize the refined simulation of multi-process and multi-element in the watershed. Each simulation unit has its own set of hydrological parameters, and can carry out a separate vertical hydrological simulation, and then realize the horizontal connection through the grid topology relationship, and finally get the slope, The runoff in the underground and in the river course provides technical support for the comprehensive management of the river basin and the optimal allocation of water and soil resources.

Example 2

The present embodiment provides a system for identifying the interaction mechanism of water and soil resources, including:

The data acquisition module M1 is used to acquire hydrological data, meteorological data, geological data and remote sensing data of the target area;

The distributed hydrological model simulation module M2 is used to perform energy process simulation, evaporation heat dissipation process simulation, vertical infiltration calculation, and slope runoff calculation according to the hydrological data, the meteorological data, the geological data and the remote sensing data , slope confluence calculation, river confluence calculation and groundwater movement calculation to obtain a distributed hydrological model; the energy process simulation includes long-wave radiation and short-wave radiation calculations; the evapotranspiration process simulation includes vegetation transpiration, vegetation interception evaporation, water evaporation, Bare soil evaporation, urban surface evaporation and building evaporation;

The runoff coefficient calculation module M3 is used to calculate and count the surface runoff at different time scales of the watershed based on the distributed hydrological model, and obtain the runoff coefficient at different time periods in the watershed space in combination with the precipitation;

The module M4 for calculating the ratio of evaporative heat dissipation to net primary productivity is used to calculate and count evaporative heat dissipation at different time scales of the watershed based on the distributed hydrological model and to determine the ratio of evaporative heat dissipation to net primary productivity in combination with the net primary productivity of different land use types ratio;

The water and soil resources interaction law acquisition module M5 is configured to determine the water and soil resources interaction law according to the runoff coefficient and the ratio of the evaporative heat dissipation to the net primary productivity.

In this paper, specific examples are used to illustrate the principles and implementations of the present invention. The descriptions of the above embodiments are only used to help understand the methods and core ideas of the present invention; meanwhile, for those skilled in the art, according to the present invention There will be changes in the specific implementation and application scope. In conclusion, the contents of this specification should not be construed as limiting the present invention.

Claims (9)

1. A method and a system for identifying a water and soil resource mutual feedback mechanism are characterized by comprising the following steps:

acquiring hydrological data, meteorological data, geological data and remote sensing data of a target area;

performing energy process simulation, evaporation heat dissipation process simulation, vertical infiltration calculation, slope runoff production calculation, slope confluence calculation, river confluence calculation and groundwater movement calculation according to the hydrological data, the meteorological data, the geological data and the remote sensing data to obtain a distributed hydrological model; the energy process simulation comprises long-wave radiation and short-wave radiation calculation; the transpiration process simulation comprises vegetation transpiration, vegetation interception evaporation, water area evaporation, bare soil evaporation, urban surface evaporation and building evaporation;

calculating and counting the surface flow rates of the watershed at different time scales based on the distributed hydrological model, and obtaining flow rate coefficients at different time periods in the watershed space by combining precipitation;

calculating and counting the evaporation heat dissipation capacity of the basin at different time scales based on the distributed hydrological model, and determining the ratio of the evaporation heat dissipation capacity to the net primary productivity by combining the net primary productivity of different land utilization types;

and determining the interaction law of water and soil resources according to the current generation coefficient and the ratio of the evaporative heat dissipation to the net primary productivity.

2. The method according to claim 1, wherein the acquiring of the hydrological data, meteorological data, geological data and remote sensing data of the target area specifically comprises:

on the basis of the digital elevation model DEM of the target area, performing filling calculation, flow direction calculation and confluence cumulant calculation by using a hydrological analysis tool to generate a basin, and obtaining basin hydrological analysis data;

cutting the digital elevation model DEM by taking a drainage basin range in the drainage basin water analysis data as a boundary condition to obtain drainage basin elevation data, soil type data, soil thickness data, land utilization type data and river network data;

selecting weather stations and rainfall stations within the drainage basin range and the preset range, and numbering the weather stations and the rainfall stations in sequence;

respectively drawing Thiessen polygons of the weather station and the rainfall station by utilizing a Thiessen polygon creating tool;

respectively converting the drawn Thiessen polygon mounting weather station number and the drawn Thiessen polygon mounting weather station number into raster files by taking the drainage basin range as a boundary;

extracting meteorological data and precipitation data based on the raster file;

acquiring latitude and elevation of a meteorological station, change rate of rainfall along with elevation, vegetation coverage data of each month, leaf area index data of each month, reflectivity of various land utilization earth surfaces to short wave radiation, saturated water content of various soils, field water retention rate of various soils, withering coefficients of various soils, depression storage amount of various land utilization types, transverse-longitudinal-vertical permeability coefficients of various soil layers, domatic Manning coefficients and riverway Manning coefficients based on the grid file.

3. The method according to claim 2, wherein the calculating and counting of the evaporative heat dissipation capacity of the basin on different time scales based on the distributed hydrological model and the determining of the ratio of the evaporative heat dissipation capacity to the net primary productivity in combination with the net primary productivity of different land use types comprises:

calculating and counting evaporation heat dissipation amounts of different time scales of a basin based on the distributed hydrological model;

obtaining a spatial distribution of net primary productivity within the territory using the net primary productivity quotients of the different land use types and the spatial distribution of land use;

determining a ratio between said heat rejected by evaporation and said net primary productivity spatially, resulting in a spatial distribution of said ratio of heat rejected by evaporation and said net primary productivity over different time scales.

4. The method of claim 3, wherein determining a water and soil resource interaction law from said current generation coefficient and said ratio of evaporative heat rejection to net primary productivity comprises:

and taking the runoff yield coefficients of different time periods in the watershed space as indexes for researching the influence of the land resources on water resources, taking the spatial distribution of the ratio of the evaporative heat dissipation capacity to the net primary productivity in different time scales as indexes for researching the influence of the water resources on the land resources, and analyzing the mutual feedback effect of the water and soil resources from two angles of time and space.

5. The method according to claim 2, wherein the performing energy process simulation, evaporative heat dissipation process simulation, vertical infiltration calculation, slope runoff calculation, slope confluence calculation, river confluence calculation, and groundwater movement calculation according to the hydrological data, the meteorological data, the geological data, and the remote sensing data to obtain the distributed hydrological model specifically comprises:

finely classifying the types of the underlying surfaces according to the national standard 'classification of the current situation of land utilization'; the refined classification represents that the types of the underlying surfaces are divided into preset classification numbers;

calculating long wave radiation and short wave radiation for each underlying surface to carry out energy process simulation;

simulating the evaporation and heat dissipation process according to the vegetation transpiration condition, the vegetation interception evaporation condition, the water evaporation condition, the bare soil evaporation condition, the urban landmark evaporation condition and the building evaporation condition;

vertical infiltration calculation and slope runoff calculation are carried out in the process of calculating the variation of the soil water and the underground water;

simulating slope convergence and river convergence by using a motion wave model;

and simulating the underground water movement according to the Darcy formula.

6. The method according to claim 5, wherein the vertical infiltration calculation and the slope runoff calculation are performed in the process of calculating the variation of the soil water and the groundwater, and specifically comprise:

acquiring the net rainfall of the rainfall entering the soil through interception and depression filling;

acquiring a first water amount for supplying the soil with the net rainfall infiltration;

obtaining a second water amount evaporated to return to the atmosphere and a third water amount evaporated from the vegetation to the atmosphere;

obtaining a fourth amount of water that is ultimately retained in the soil;

and determining the process of exchanging the surface water with the underground water according to the net rainfall of the soil, the first water amount, the second water amount, the third water amount and the fourth water amount, and further realizing vertical infiltration calculation and slope runoff yield calculation.

7. The method according to claim 5, wherein the simulating of slope convergence and river convergence by using the motion wave model specifically comprises:

determining the topological relation and the calculation sequence of a slope surface grid and a river course grid through confluence cumulant and flow direction on the basis of a river network water system generated by the DEM;

and (3) constructing a water balance equation in the grid according to the continuity equation, and quantifying the motion wave equation data by combining a Manning formula and a river course end surface equation to obtain simulated slope convergence and simulated river course convergence.

8. The method according to claim 5, wherein the simulating of groundwater movement according to Darcy's formula comprises:

mesh generation is carried out on the underground water simulation area;

applying mass conservation and Darcy formula to a single grid to obtain the flow between two adjacent grids;

selecting a central grid in the grids, and determining a first flow rate of peripheral grids flowing into the corresponding central grid for each central grid according to the flow rate between two adjacent grids; the peripheral grid refers to a grid connected with the central grid, and the central grid is a grid surrounded by other grids;

calculating a second flow rate of any source of the aquifer to the central grid;

calculating a third flow rate of an aquifer multi-source flow to the central grid;

determining a difference equation of each grid according to the first flow, the second flow and the third flow in combination with the continuity equation;

and obtaining the water level condition of each grid according to the difference equation of each grid.

9. A water and soil resource mutual feedback mechanism recognition system is characterized by comprising:

the data acquisition module is used for acquiring hydrological data, meteorological data, geological data and remote sensing data of a target area;

the distributed hydrological model simulation module is used for carrying out energy process simulation, evaporation and heat dissipation process simulation, vertical infiltration calculation, slope runoff calculation, slope confluence calculation, river confluence calculation and underground water movement calculation according to the hydrological data, the meteorological data, the geological data and the remote sensing data to obtain a distributed hydrological model; the energy process simulation comprises long-wave radiation and short-wave radiation calculation; the simulation of the evapotranspiration process comprises vegetation transpiration, vegetation interception and evaporation, water evaporation, bare soil evaporation, urban land surface evaporation and building evaporation;

the flow production coefficient calculation module is used for calculating and counting the surface flow production of the drainage basin at different time scales based on the distributed hydrological model and obtaining the flow production coefficient of the drainage basin at different time periods by combining precipitation;

the ratio calculation module of the evaporative heat dissipation and the net primary productivity is used for calculating and counting the evaporative heat dissipation capacity of the basin at different time scales based on the distributed hydrological model and determining the ratio of the evaporative heat dissipation and the net primary productivity by combining the net primary productivity of different land utilization types;

and the water and soil resource interaction rule acquisition module is used for determining the water and soil resource interaction rule according to the runoff yield coefficient and the ratio of the evaporative heat dissipation to the net primary productivity.

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