CN110686862A - Flow process rasterization method based on soil infiltration capacity - Google Patents

Abstract

The present invention proposes a flow process rasterization method based on soil infiltration capacity, comprising: step S1, converting the flow process line of the watershed outlet section into a water level process line through the water level-flow relationship curve; step S2, according to the land use Type and soil characteristic data, determine the flow distribution weight in different grids; Step S3, determine the distribution ratio of runoff in different grids, and calculate the distribution ratio of all grids in the watershed according to the flow distribution weight of each grid; Step S4, According to the distribution ratio, the flow of the outlet section of the watershed is distributed into each grid, and the flow is rasterized. The invention considers the influence of the soil infiltration capacity of different grids in the watershed on the runoff, follows the runoff runoff mechanism and the physical mechanism of the hydrological process in the watershed, reduces the problem of calculation error caused by the average distribution, and the calculation process is simple, easy to operate, and easy to use. promotion.

Description

A rasterization method of flow process based on soil infiltration capacity

technical field

The invention relates to the technical field of data downscaling, in particular to a flow process rasterization method based on soil infiltration capacity.

Background technique

The coupling of hydrological forecasting and hydrodynamic forecasting is one of the hot issues in hydrological research. The important link involved in the hydrology-hydrodynamic coupling method is the connection of data between the two. The calculation result of the hydrological model is that the flow process of the watershed outlet section is used as the input of the two-dimensional hydrodynamic model, and the two-dimensional hydrodynamic model is based on the grid. To calculate with grid data, it is necessary to convert the hydrological data of one-dimensional spatial scale to two-dimensional spatial scale, that is, rasterization, before it can be used for calculation. However, there is no mature flow data rasterization method at present. The commonly used method is to distribute the flow evenly to each grid. The disadvantage of this method is that the spatial heterogeneity of the watershed is not considered, that is, the soil infiltration of each grid. The capabilities are different, and such processing will directly lead to large errors in the spatial distribution of the two-dimensional hydrodynamic calculation results.

SUMMARY OF THE INVENTION

The purpose of the present invention is to solve at least one of the technical defects.

Therefore, the purpose of the present invention is to propose a flow process rasterization method based on soil infiltration capacity.

In order to achieve the above object, an embodiment of the present invention provides a flow process rasterization method based on soil infiltration capacity, including the following steps:

In step S1, the flow hydrograph of the outlet section of the watershed is converted into a water level hydrograph through the water level-flow relationship curve;

Step S2, according to the land use type and soil characteristic data, determine the flow distribution weights in different grids;

Step S3, determine the distribution ratio of the runoff flow of different grids, and calculate the distribution ratio of all grids in the watershed according to the flow distribution weight of each grid;

In step S4, the flow of the outlet section of the watershed is allocated to each grid according to the distribution ratio, so as to realize the flow grid.

Further, in the step S2, the land use type is a water permeability factor; the soil characteristic data includes: soil structure and initial moisture content.

Further, in the step S2, the flow distribution weights in different grids are determined, including determining the weights representing the soil infiltration capacity of different grids.

Further, in the step S3, calculating the distribution ratio of all the grids in the watershed according to the flow distribution weight of each grid, including:

Among them, P _i,j represents the water permeability factor of grid (i, j); Si _{, j} represents the soil structure of grid (i, j); Wi _{, j} is the initial water content of grid (i, j) i, j represent the serial number of the grid in the x, y direction respectively; m, n are the total number of grids in the x, y direction of the two-dimensional grid; PR _{i, j} is the distribution ratio of net rainfall in different grids.

Further, in the step S4, the flow of the outlet section of the watershed is distributed to each grid according to the distribution ratio, including:

EP _i,j =PR _i,j ×NR,

Among them, EP _{i, j} represents the grid value of the flow; NR is the flow value of the outlet section of the watershed at a certain time. 6

According to the rasterization method of flow process based on soil infiltration capacity according to the embodiment of the present invention, it is proposed to use soil characteristic data (water permeability factor, soil structure, initial water content) to characterize soil infiltration capacity, and fully consider these three factors to the watershed The influence of runoff and runoff, considering the influence of soil infiltration capacity of different grids on runoff in the basin, following the runoff runoff mechanism and the physical mechanism of the hydrological process in the basin, reducing the calculation error caused by the average distribution, the calculation process is simple and good Operation and easy promotion. The present invention follows the drainage and confluence mechanism and the physical mechanism of the hydrological process, reduces the calculation error caused by the simple average in the traditional method, and the result can be directly applied to the simulation calculation of the two-dimensional hydrodynamic model.

Additional aspects and advantages of the present invention will be set forth, in part, from the following description, and in part will be apparent from the following description, or may be learned by practice of the invention.

Description of drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of embodiments taken in conjunction with the accompanying drawings, wherein:

1 is a flowchart of a flow process rasterization method based on soil infiltration capacity according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of a flow process rasterization method based on soil infiltration capacity according to an embodiment of the present invention.

Detailed ways

Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary, and are intended to explain the present invention and should not be construed as limiting the present invention.

As shown in FIG. 1 and FIG. 2 , the method for rasterizing a flow process based on soil infiltration capacity according to an embodiment of the present invention includes the following steps:

In step S1, the flow hydrograph of the outlet section of the watershed is converted into a water level hydrograph (NR, unit: meter) through the water level-flow relationship curve. This is due to the fact that flow must be converted to water level for subsequent calculations.

Step S2: Determine the flow distribution weights in different grids according to the land use type and soil characteristic data.

In this step, the permeability factor P is determined with reference to the land use type, and the weights of common land use types are ranked as forest land < sparse forest land < shrub forest < grassland < cultivated land < bare land < water area < construction land. The roughness ratio of different land use types is determined.

The soil characteristic data includes: soil structure S and initial moisture content W. The soil structure is usually divided into three types: compaction, undisturbed state, and loosening. The specific value is determined by referring to the infiltration rates of different soil structures. The initial moisture content is determined according to the actual situation, and the percentage can be directly used for calculation in practical application.

It should be noted that the determination of the flow distribution weights in different grids is to determine the weights that characterize the soil infiltration capacity of different grids.

Specifically, in this step, the reference values of different grid permeability factors are determined according to the land use type, as shown in Table 1. The types of land use include: woodland, sparse woodland, shrub forest, grassland, cultivated land, bare land, water area and construction land. Table 1 is obtained based on application experience and physical experiments. Reference value of soil structure (1 for compaction, 0.7 for undisturbed state, and 0.3 for loosening).

Table 1 Reference values of different grid permeability factors

land use type woodland open woodland bush grassland arable land bare ground waters construction land water permeability factor 1 2 3 6.5 7 8.5 10 10

In step S3, the distribution ratio of the runoff flow of different grids is determined, and the distribution ratio of all the grids in the watershed is calculated according to the flow distribution weight of each grid.

Specifically, the distribution ratio of all grids in the watershed is calculated according to the flow distribution weight of each grid, including:

Among them, P _i,j represents the water permeability factor of grid (i, j); Si _{, j} represents the soil structure of grid (i, j); Wi _{, j} is the initial water content of grid (i, j) i, j represent the serial number of the grid in the x, y direction respectively; m, n are the total number of grids in the x, y direction of the two-dimensional grid; PR _{i, j} is the distribution ratio of net rainfall in different grids.

In step S4, the flow of the outlet section of the watershed is allocated to each grid according to the distribution ratio, so as to realize the flow grid.

Specifically, according to the distribution ratio, the following formula is used to distribute the surface runoff process, that is, the watershed runoff (net rainfall), into each grid, including:

EP _i,j =PR _i,j ×NR,

Among them, EP _{i, j} represents the grid value of the flow; NR is the surface runoff process of the outlet section of the watershed at a certain time, that is, the watershed runoff (net rainfall).

According to the rasterization method of flow process based on soil infiltration capacity according to the embodiment of the present invention, it is proposed to use soil characteristic data (water permeability factor, soil structure, initial water content) to characterize soil infiltration capacity, and fully consider these three factors to the watershed The influence of runoff and runoff, considering the influence of soil infiltration capacity of different grids on runoff in the basin, following the runoff runoff mechanism and the physical mechanism of hydrological process in the basin, reducing the calculation error caused by the average distribution, the calculation process is simple and good Operation and easy promotion. The present invention follows the basin production and confluence mechanism and the physical mechanism of the hydrological process, reduces the calculation error caused by the simple average in the traditional method, and the result can be directly applied to the simulation calculation of the two-dimensional hydrodynamic model.

In the description of this specification, description with reference to the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples", etc., mean specific features described in connection with the embodiment or example , structure, material or feature is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Although the embodiments of the present invention have been shown and described above, it should be understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and those of ordinary skill in the art will not depart from the principles and spirit of the present invention Variations, modifications, substitutions, and alterations to the above-described embodiments are possible within the scope of the present invention without departing from the scope of the present invention. The scope of the invention is defined by the appended claims and their equivalents.

Claims (5)

1. A flow process rasterization method based on soil infiltration capacity is characterized by comprising the following steps:

step S1, converting the flow process line of the cross section of the basin outlet into a water level process line through a water level-flow relation curve;

step S2, determining flow distribution weights in different grids according to the land utilization type and the soil characteristic data;

step S3, determining the distribution proportion of the radial flow of different grids, and calculating the distribution proportion of all grids in the watershed according to the flow distribution weight of each grid;

and step S4, distributing the flow of the outlet section of the basin into each grid according to the distribution proportion to realize flow rasterization.

2. The soil infiltration capacity-based flow process rasterization method of claim 1 wherein in said step S2, said land use type is a water permeability factor; the soil characteristic data includes: soil structure and initial water content.

3. The soil infiltration capacity-based flow process rasterization method of claim 1 wherein in said step S2, determining flow distribution weights within different grids includes determining weights characterizing the soil infiltration capacity of different grids.

4. The soil infiltration capacity-based flow process rasterization method of claim 1, wherein in the step S3, the calculating the distribution proportion of all grids in the drainage basin according to the flow distribution weight of each grid includes:

wherein, P_i，jCharacterizing a water permeability factor of the grid (i, j); s_i，jCharacterizing the soil structure of grid (i, j); w_i，jIs the initial moisture content of the grid (i, j); i and j respectively represent the serial numbers of the grids in the x and y directions; m and n are the total number of the grids in the x and y directions of the two-dimensional grid; PR_i，jThe distribution proportion of net rainfall for different grids.

5. The soil infiltration capacity-based flow process rasterization method of claim 1 wherein in said step S4, said distributing the flow of watershed outlet sections into each grid according to distribution proportions comprises:

EP_i，j＝PR_i，j×NR，

among them, EP_i，jA grid value representing a flow rate; NR is the flow value of the outlet section of the basin at a certain moment.

Images