Urban catchment capability evaluation system and method based on ecological data analysis

Abstract

The invention discloses an urban water collection capability evaluation system and method based on ecological data analysis, and relates to the technical field of urban water collection. Comprising the following steps: a soil information acquisition module divides a to-be-evaluated region into sub-regions, acquires soil feature information and calculates a soil water holding capacity index; and the water holding capacity analysis module is combined with the average vegetation coverage density and the soil permeability to correct the water holding capacity index of the soil. The evaporation potential analysis module is used for calculating the water evaporation capacity and generating an evaporation potential index based on the maximum bearing volume of the water body and the meteorological parameters. And the terrain factor analysis module corrects the evaluation coefficient and considers the ground average slope angle. And the catchment capability evaluation module dynamically adjusts a catchment capability evaluation threshold according to the average rainfall and the soil humidity, and finally generates an urban catchment capability evaluation result. The system improves the adaptability and effectiveness of urban catchment capacity evaluation.

Description

Technical Field

[0001] The present invention relates to the technical field of urban water collection, and specifically to an urban water collection capacity evaluation system and method based on ecological data analysis. Background Art

[0002] With the acceleration of the urbanization process, urban areas are facing increasingly severe challenges in water resource management. The insufficient urban water collection capacity not only affects the effective management of rainwater but may also lead to problems such as urban waterlogging, soil erosion, and ecological environment deterioration. Traditional urban water collection capacity evaluation methods often focus on single-factor analysis and lack comprehensive consideration of multiple factors such as soil characteristics, vegetation cover, meteorological changes, and terrain. This makes the evaluation results unable to accurately reflect the real urban water collection capacity and insufficient in early warning capabilities in the face of extreme weather conditions.

[0003] Existing technologies often rely on static data or monitoring at a single time point and are difficult to reflect changes in a dynamic environment in real time. In addition, indicators such as the water holding capacity of the soil and evaporation potential vary greatly under different spatio-temporal conditions, and a single static evaluation cannot meet the water resource management and regulation needs of cities. Therefore, establishing an urban water collection capacity evaluation system based on multi-dimensional ecological data analysis, which can effectively integrate various influencing factors and conduct dynamic and real-time evaluations, has become a technical problem to be solved urgently.

[0004] In the prior art, the publication number CN118627935B discloses an urban water collection capacity evaluation system and method based on ecological data analysis, including: dividing the total water collection monitoring area of the city into monitoring sub-areas, calculating the extreme value of rainfall water collection degree of each monitoring sub-area m within the monitoring period T; calculating the rainfall water collection characterization values of n monitoring sub-areas; comparing with the rainfall water collection characterization threshold; obtaining the water collection stable signal of the total monitoring area; then calculating the excellent coverage rate of rainfall water collection; comparing with the excellent qualification rate of rainfall water collection to obtain the water collection qualified signal of the total monitoring area, ensuring that the excellent coverage rate of rainfall water collection in the total monitoring area meets the standard, so that the monitoring sub-areas in the total monitoring area can bear the precipitation risk of adjacent monitoring sub-areas to reduce the precipitation risk of the entire total monitoring area and improve the rainfall water collection state of the total monitoring area. However, in this solution, the extreme value of rainfall water collection degree may be greatly affected by extreme weather events, and the frequent changes in extreme value calculation may lead to fluctuations in the judgment standard, and the data is single. At the same time, the water evaporation amount, soil water holding capacity, and terrain and their impacts on the water collection capacity are not considered. Therefore, the accuracy and effectiveness of the evaluation system are reduced by this method.

[0005] The above information disclosed in the background art section is only used to enhance the understanding of the background of the present disclosure, and thus it may include information that does not constitute the prior art known to those of ordinary skill in the art. Summary of the Invention

[0006] An object of the present invention is to provide an urban water collection capacity evaluation system and method based on ecological data analysis to solve the problems raised in the above background art.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] An urban water collection capacity evaluation system based on ecological data analysis specifically includes:

[0009] A soil information collection module for equally dividing the area of the urban area to be evaluated into several sub-regions, and simultaneously collecting the soil characteristic information in each sub-region multiple times, and calculating the soil water holding capacity index based on the soil characteristic information, where the soil characteristic information includes the average soil particle size, the average field water holding capacity of the soil, and the average dry density of the soil;

[0010] A water holding capacity analysis module for obtaining the average vegetation coverage density and soil permeability of each sub-region, and correcting the soil water holding capacity index of the corresponding sub-region according to the obtained average vegetation coverage density and soil permeability to obtain the accurate value of the soil water holding capacity index;

[0011] An evaporation potential analysis module for collecting the maximum water body carrying volume and meteorological parameters in each sub-region, calculating the water evaporation amount of the corresponding sub-region based on the meteorological parameters in each sub-region, and calculating and generating an evaporation potential index according to the obtained water evaporation amount, in combination with the maximum water body carrying volume and meteorological parameters in each sub-region, where the meteorological parameters include air humidity, air temperature, and wind speed;

[0012] A terrain factor analysis module for calculating and generating an urban water collection capacity evaluation coefficient based on the obtained evaporation potential index and the accurate value of the soil water holding capacity index, and simultaneously obtaining the average ground slope angle of each sub-region, and correcting the urban water collection capacity evaluation coefficient according to the average ground slope angle to obtain the accurate value of the urban water collection capacity evaluation coefficient;

[0013] A water collection capacity evaluation module for obtaining the average rainfall and the real-time average soil humidity of the urban area to be evaluated, dynamically correcting the pre-set water collection capacity evaluation threshold according to the average rainfall and the real-time average soil humidity to obtain the corrected value of the water collection capacity evaluation threshold, comparing the accurate value of the urban water collection capacity evaluation coefficient with the corrected value of the water collection capacity evaluation threshold, and generating the corresponding urban water collection capacity evaluation result according to the obtained comparison result.

[0014] Furthermore, the specific method for collecting soil characteristic information in each sub-region simultaneously in real time and multiple times includes: equally dividing the urban area to be evaluated into m sub-regions, collecting soil samples at different depths, analyzing the collected soil samples to obtain soil characteristic information. The depth range for collecting soil samples includes: 0 - 10 cm, 10 - 20 cm, 20 - 30 cm, 30 - 40 cm, and 40 - 50 cm. The collection method is: randomly collect 1 soil sample within each depth range in the sub-region, obtain the numerical values of each parameter of its soil characteristic information, calculate the average value of the soil characteristic information numerical values at 5 different depths, and use this average value as the soil characteristic information of the sub-region, including the average soil particle size, the average field water holding capacity of the soil, and the average dry density of the soil.

[0015] Furthermore, the soil water holding capacity index is calculated based on the soil characteristic information. The specific formula for calculating the soil water holding capacity index is:

[0016]

[0017] In the formula, ECI is the soil water holding capacity index, BD is the average dry density of the soil, HC is the average field water holding capacity of the soil, and D mean is the average soil particle size;

[0018] According to the obtained average vegetation cover density and soil permeability, the soil water holding capacity index of the corresponding sub-region is corrected to obtain the accurate value of the soil water holding capacity index. The formula for calculating the accurate value of the soil water holding capacity index is:

[0019]

[0020] In the formula, ECI′ is the accurate value of the soil water holding capacity index, VC is the average vegetation cover density, and K is the soil permeability.

[0021] Furthermore, the specific method for obtaining the soil permeability K is: select the soil sample to be tested, put it into a cylindrical permeameter. The sample needs to be fully saturated before being put in. Set a constant water level difference, that is, maintain a constant height difference between the water source of the permeameter and the water level above the soil sample. Record the amount of water flowing through the soil sample within the time period t, and calculate the soil permeability based on the recorded data. Among them, the specific formula for calculating the soil permeability K is:

[0022]

[0023] In the formula, Q is the amount of water flowing through the soil sample within the time period t, L is the thickness of the soil sample in the permeameter, PF is the cross-sectional area of the soil sample in the permeameter, and h is the set water level difference.

[0024] Further, collect the maximum water-bearing volume and meteorological parameters in each sub-region, and calculate the water evaporation amount of the corresponding sub-region based on the meteorological parameters in each sub-region. The formula for calculating the water evaporation amount is as follows:

[0025]

[0026] In the formula, e s -e a is the saturation vapor pressure deficit, with the unit of kPa. The soil water evaporation amount is ET0, with the unit of mm. u n is the net radiation on the surface of the crop canopy, with the unit of MJm -2 d -1 ; G is the soil heat flux, with the unit of MJm -2 d -1 ; γ is the psychrometer constant, with the unit of kPa℃ -1 , T m is the daily average air temperature, with the unit of ℃. V m is the daily average wind speed, with the unit of ms -1 , Δ is the slope of the vapor pressure curve, with the unit of kPa℃ -1 ;

[0027] According to the obtained water evaporation amount, combined with the maximum water-bearing volume and meteorological parameters in each sub-region, calculate and generate the evaporation potential index. The formula for calculating the evaporation potential index is as follows:

[0028]

[0029] In the formula, SCI is the evaporation potential index, HR m is the average air relative humidity, and A is the maximum water-bearing volume of the water body.

[0030] Further, based on the obtained evaporation potential index and the accurate value of the soil water holding capacity index, calculate and generate the urban water collection capacity evaluation coefficient. The formula for calculating the urban water collection capacity evaluation coefficient is as follows:

[0031] ZH = ω1 * SCI 2 + ω2 * ln(1 + ECI′)

[0032] In the formula, ZH is the urban water collection capacity evaluation coefficient, and ω1 and ω2 are the weight coefficients of the accurate values of the evaporation potential index and the soil water holding capacity index respectively, where ω1 ≤ ω2 and both ω1 and ω2 are greater than 0;

[0033] According to the ground average slope angle, correct the urban water collection capacity evaluation coefficient to obtain the accurate value of the urban water collection capacity evaluation coefficient. The formula for calculating the accurate value of the urban water collection capacity evaluation coefficient is as follows:

[0034] ZH′ = ZH * (1 + sinθ)

[0035] Where θ is the average ground slope angle, and the average ground slope angle specifically refers to the average value of the angle between the land in this sub-region and the horizontal plane.

[0036] Furthermore, compare the exact value of the urban water collection capacity evaluation coefficient with the corrected value of the water collection capacity evaluation threshold, and generate the corresponding urban water collection capacity evaluation result according to the obtained comparison result. The specific judgment logic is as follows:

[0037] When ZH′ ≥ 1.0 * yz, it is judged that the water collection capacity of this sub-region is high, indicating that this sub-region can collect and discharge rainwater, reducing the risk of urban waterlogging;

[0038] When 0.4 * yz ≤ ZH′ < 1.0 * yz, it is judged that the water collection capacity of this sub-region is medium, indicating that there is a risk of urban waterlogging in this sub-region under extreme rainfall conditions;

[0039] When 0 ≤ ZH′ < 0.4 * yz, it is judged that the water collection capacity of this sub-region is low, indicating that there are serious waterlogging problems in this sub-region when facing rainfall, and improvement measures should be taken in a timely manner;

[0040] Where yz is the corrected value of the water collection capacity evaluation threshold, and the specific calculation formula is:

[0041]

[0042] In the formula, yz0 is the preset water collection capacity evaluation threshold, Rz is the average rainfall, specifically the average monthly rainfall, HR S is the current average soil humidity, HR0 is the reference humidity, and Rz0 is the reference rainfall, where Rz0 > Rz.

[0043] The present invention also provides a method for evaluating the urban water collection capacity based on ecological data analysis. The method for evaluating the urban water collection capacity based on ecological data analysis is used to control the above-mentioned system for evaluating the urban water collection capacity based on ecological data analysis. The specific steps include:

[0044] Divide the urban area to be evaluated into several equal-area sub-regions, and collect the soil characteristic information in each sub-region simultaneously for multiple times. Calculate the soil water holding capacity index based on the soil characteristic information. The soil characteristic information includes the average soil particle size, the average field water holding capacity of the soil, and the average dry density of the soil;

[0045] Obtain the average vegetation coverage density and soil permeability of each sub-region, and correct the soil water holding capacity index of the corresponding sub-region according to the obtained average vegetation coverage density and soil permeability to obtain the exact value of the soil water holding capacity index;

[0046] Collect the maximum water-carrying volume and meteorological parameters in each sub-region, calculate the water evaporation amount of the corresponding sub-region based on the meteorological parameters in each sub-region, and calculate and generate an evaporation potential index according to the obtained water evaporation amount, in combination with the maximum water-carrying volume and meteorological parameters in each sub-region. The meteorological parameters include air humidity, air temperature, and wind speed;

[0047] Calculate and generate an urban water collection capacity evaluation coefficient based on the obtained evaporation potential index and the accurate value of the soil water-holding capacity index. At the same time, obtain the average ground slope angle of each sub-region, and correct the urban water collection capacity evaluation coefficient according to the average ground slope angle to obtain the accurate value of the urban water collection capacity evaluation coefficient;

[0048] Obtain the average rainfall and the real-time average soil humidity of the urban area to be evaluated, dynamically correct the pre-set water collection capacity evaluation threshold according to the average rainfall and the real-time average soil humidity to obtain the corrected value of the water collection capacity evaluation threshold, compare the accurate value of the urban water collection capacity evaluation coefficient with the corrected value of the water collection capacity evaluation threshold, and generate the corresponding urban water collection capacity evaluation result according to the obtained comparison result.

[0049] Compared with the prior art, the beneficial effects of the present invention are:

[0050] First of all, through the soil information collection module, the system carefully divides the urban area into several sub-regions and collects soil characteristic information multiple times. This method makes the calculation of the soil water-holding capacity index more accurate and can truly reflect the water retention capacity of each sub-region. Secondly, the water-holding capacity analysis module corrects the soil water-holding capacity index in combination with the vegetation coverage density and soil permeability, further enhancing the reliability of the evaluation. Vegetation coverage and permeability are important factors affecting soil water retention. Through comprehensive analysis, the interaction between soil and vegetation can be better understood, providing an important basis for urban ecological construction. In addition, the evaporation potential analysis module introduces the analysis of meteorological parameters and the maximum water-carrying volume of water bodies, enabling the system to comprehensively consider the impact of climate change on water evaporation. It not only helps to accurately evaluate the water evaporation amount of a certain sub-region but also can calculate the evaporation potential index in combination with the carrying capacity of water bodies. Through the quantitative analysis of the evaporation potential, the dynamic changes of water resources can be better grasped. Finally, the terrain factor analysis module considers the influence of the average ground slope angle on the water collection capacity, and corrects the urban water collection capacity evaluation coefficient, making the evaluation result more in line with the actual terrain conditions. This analysis can effectively solve the evaluation error caused by terrain complexity and improve the adaptability and effectiveness of urban water collection capacity evaluation. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 It is a schematic structural flow chart of the system of the present invention;

[0052] Figure 2 Schematic diagram of the overall method flow of the present invention Specific implementation manners

[0053] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to specific embodiments.

[0054] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the present invention should have the ordinary meanings understood by those of ordinary skill in the field to which the present invention belongs. The "first", "second" and similar terms used in the present invention do not denote any order, quantity or importance, but are only used to distinguish different components. The terms such as "comprising" or "including" mean that the elements or items appearing before this term cover the elements or items listed after this term and their equivalents, without excluding other elements or items. The terms such as "connected" or "coupled" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The terms such as "upper", "lower", "left" and "right" are only used to represent relative positional relationships, and when the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0055] Embodiment:

[0056] Please refer to Figure 1 , the present invention provides a technical solution:

[0057] An urban water collection capacity evaluation system based on ecological data analysis, specifically including:

[0058] A soil information collection module, configured to equally divide the area of the urban area to be evaluated into several sub-regions, and simultaneously collect the soil characteristic information in each sub-region multiple times, and calculate the soil water holding capacity index based on the soil characteristic information, where the soil characteristic information includes the average soil particle size, the average field water holding capacity of the soil, and the average dry density of the soil.

[0059] The specific method for real-time multiple simultaneous acquisition of soil characteristic information in each sub-region includes: equally dividing the urban area to be evaluated into m sub-regions, collecting soil samples at different depths, analyzing the collected soil samples to obtain soil characteristic information, where the depth range for soil sample collection includes: 0 - 10 cm, 10 - 20 cm, 20 - 30 cm, 30 - 40 cm, and 40 - 50 cm. The collection method is: randomly collect 1 soil sample within each depth range in the sub-region, obtain the numerical values of each parameter of its soil characteristic information, calculate the average value of the soil characteristic information numerical values at 5 different depths, and use this average value as the soil characteristic information of the sub-region, including the average soil particle size, the average field water holding capacity of the soil, and the average dry density of the soil.

[0060] Among them, the method for obtaining soil characteristic information based on the collected soil samples specifically includes: selecting several sampling points within each sub-region, using standardized sampling tools (such as soil drills or soil samplers) to collect soil samples at a certain depth; air-drying the collected soil samples, removing organic matter and large particles, and then grading the soil particles through a sieve; using a laser particle size analyzer or sedimentation method (such as the Hunt method) to measure the size distribution of soil particles. According to the particle distribution data, calculate the average soil particle size by the method of weighted average.

[0061] The specific method for obtaining the average field water holding capacity of the soil is: put the soil sample into a container with a known volume, add water until it reaches the saturated state, after a certain period of time (usually 24 hours), measure the humidity and weight of the sample to determine its field water holding capacity; use a soil moisture tensiometer (such as TDR or frequency domain reflectometer) to measure the water content of the soil in the field water holding state. These instruments can directly measure the water content of the soil and provide real-time data. After measuring at multiple sampling points, calculate the average value of the field water holding capacity at each point to obtain the average field water holding capacity of the sub-region, where the average field water holding capacity of the soil specifically refers to the average value of the field water holding capacity of all sampling points within the sub-region.

[0062] The method for obtaining the average dry density of the soil is: put the soil sample into an oven and dry it to a constant weight (usually dried at 105 °C for 24 hours), and then weigh the dry weight of the soil sample. Calculate the dry density through the following formula:

[0063]

[0064] Conduct multiple samplings within each sub-region and calculate the dry density of each sampling point, and then take the average value to obtain the average dry density of the soil.

[0065] Calculate the soil water holding capacity index based on the soil characteristic information, where the specific formula for calculating the soil water holding capacity index is:

[0066]

[0067] In the formula, ECI is the soil water holding capacity index, BD is the average dry density of the soil, HC is the average field water holding capacity of the soil, and D mean is the average particle size of the soil.

[0068] It should be noted that the soil water holding capacity is characterized by comprehensively considering the dry density, particle size, and field water holding capacity. Among them, the larger the value of the soil water holding capacity index ECI, the stronger the soil water holding capacity and the more water it can hold.

[0069] Among them, the average field water holding capacity HC of the soil represents the amount of water that the soil can hold under the field water holding state, which directly affects the soil water storage capacity. The larger its value, the greater the amount of water that the soil can hold under the field water holding state. Therefore, the average field water holding capacity HC of the soil is proportional to the soil water holding capacity index ECI. By squaring HC 2 , it means that the relationship between the soil water holding capacity and the field water holding capacity is non-linear. A higher field water holding capacity has a significant enhancing effect on the water retention capacity. This reflects the cumulative effect of the soil during water storage.

[0070] The average dry density BD of the soil represents the mass of the soil per unit volume, which is usually related to the porosity and compactness of the soil and affects the soil's water holding capacity. The higher the dry density, the lower the porosity of the soil usually is, and the water holding capacity will decrease. Therefore, the average dry density BD of the soil is inversely proportional to the soil water holding capacity index ECI. In the form of the natural logarithm ln(1 + BD), it can smoothly reflect the influence of the soil dry density on the water holding capacity, thus avoiding excessive exponential changes when the dry density is small.

[0071] The average particle size D of the soil mean , characterizes the size of the soil particles and affects the movement and retention of water in the soil. Among them, the average particle size D of the soil mean is larger, its surface area is larger, the contact area between particles becomes smaller, resulting in an increase in the porosity of the land, and the water holding capacity is usually stronger. Therefore, the average particle size D of the soil mean is proportional to the soil water holding capacity index ECI. Through the exponential function It shows that as the average particle size increases, the soil's water retention capacity shows a relatively rapid increase.

[0072] The water holding capacity analysis module is used to obtain the average vegetation coverage density and soil permeability of each sub-region. According to the obtained average vegetation coverage density and soil permeability, the soil water holding capacity index of the corresponding sub-region is corrected to obtain the accurate value of the soil water holding capacity index.

[0073] Among them, remote sensing images (such as high-resolution satellite images or photos taken by drones) are used to analyze the vegetation coverage. Through image processing software (such as GIS, ENVI, etc.), classification analysis is carried out to extract vegetation information. Indicators such as the Normalized Difference Vegetation Index (NDVI) can be used to quantitatively calculate the vegetation coverage, calculate the vegetation coverage rate of each quadrat, and average the results of all quadrats to obtain the average vegetation coverage area of the sub-region. The ratio of the average vegetation coverage area to the total area of the sub-region is used as the average vegetation coverage density.

[0074] According to the obtained average vegetation coverage density and soil permeability, the soil water holding capacity index of the corresponding sub-region is corrected to obtain the accurate value of the soil water holding capacity index. The formula based on which the accurate value of the soil water holding capacity index is calculated is:

[0075]

[0076] In the formula, ECI′ is the accurate value of the soil water holding capacity index, VC is the average vegetation coverage density, and K is the soil permeability.

[0077] It should be noted that vegetation can increase the soil's water holding capacity through its roots, improve the soil structure, and affect the dynamics of soil water through evapotranspiration. High vegetation coverage usually means better water holding capacity, thereby improving the soil's water holding capacity. At the same time, the roots of vegetation will increase the soil porosity and water holding capacity. Therefore, the average vegetation coverage density VC is proportional to the accurate value of the soil water holding capacity index ECI′.

[0078] The higher the soil permeability, the faster the water flows in the soil, resulting in the rapid entry of water into the soil after rainfall and no seepage out of the ground. Therefore, the soil permeability is proportional to the accurate value of the soil water holding capacity index ECI′.

[0079] By using the square root function The non-linear and superimposed effects of vegetation coverage and permeability on water holding capacity can be reflected. The form of the square root means that when these two factors (vegetation coverage and permeability) increase, the improvement of the soil water holding capacity is not linear, but grows in a smoother way. The combination of the square root and addition makes the effects of vegetation coverage and soil permeability on water holding capacity equally important.

[0080] The specific method for obtaining the soil permeability K is as follows: Select the soil sample to be tested and place it in a cylindrical permeameter. The sample needs to be fully saturated before being placed. Set a constant water level difference, that is, maintain a constant height difference between the water source of the permeameter and the water level above the soil sample. Record the amount of water flowing through the soil sample within the time period t, and calculate the soil permeability based on the recorded data. The specific formula based on which the soil permeability K is calculated is:

[0081]

[0082] Wherein, Q is the amount of water flowing through the soil sample within the time period t, L is the thickness of the soil sample in the permeameter, PF is the cross-sectional area of the soil sample in the permeameter, and h is the set water level difference.

[0083] An evaporation potential analysis module, configured to collect the maximum water-bearing volume and meteorological parameters in each sub-region, calculate the water evaporation amount of the corresponding sub-region based on the meteorological parameters in each sub-region, and calculate and generate an evaporation potential index according to the obtained water evaporation amount, in combination with the maximum water-bearing volume and meteorological parameters in each sub-region, where the meteorological parameters include air humidity, air temperature, and wind speed.

[0084] Collect the maximum water-bearing volume and meteorological parameters in each sub-region, and calculate the water evaporation amount of the corresponding sub-region based on the meteorological parameters in each sub-region. The formula for calculating the water evaporation amount is as follows:

[0085]

[0086] Wherein, e s -e a is the saturation vapor pressure deficit, with the unit of kPa, the soil water evaporation amount is ET0, with the unit of mm, u n is the net radiation on the surface of the crop canopy, with the unit of MJm -2 d -1 ; G is the soil heat flux, with the unit of MJm -2 d -1 ; γ is the psychrometer constant, with the unit of kPa °C -1 , T m is the daily average air temperature, with the unit of °C, V m is the daily average wind speed, with the unit of m s -1 , Δ is the slope of the vapor pressure curve, with the unit of kPa °C -1 ;

[0087] Among them, the acquisition methods of each parameter are as follows: The psychrometer constant is usually determined by the manufacturer of the psychrometer during the production process according to its design and performance characteristics. This constant usually refers to the calibration constant or correction factor of the psychrometer, which is used to convert the reading of the psychrometer into the actual humidity value. The user manual of the psychrometer can be referred to or the manufacturer can be contacted to obtain the psychrometer constant;

[0088] The acquisition method of the soil heat flux: The common methods for measuring the soil heat flux are to use a heat flux meter or a heat flux plate. These devices can be installed in the soil to measure the temperature gradient and heat flux inside the soil;

[0089] Method for obtaining net radiation on crop canopy surface: Obtain radiation parameters of downward atmospheric radiation and upward atmospheric radiation from a local weather station. The net radiation on the crop canopy surface is the difference between downward atmospheric radiation and upward atmospheric radiation. The formula for calculation is as follows:

[0090] R n = R down - R up

[0091] In the formula, R down is the value of downward atmospheric radiation on the day in the corresponding sub-region, and R up is the value of upward atmospheric radiation on the day in the corresponding sub-region.

[0092] The calculation method for saturated water vapor pressure is: Calculate the saturated water vapor pressure based on the daily average air temperature. The formula for calculation is as follows:

[0093]

[0094] In the formula, T m is the daily average air temperature, and e s is the saturated water vapor pressure;

[0095] Calculate the actual water vapor pressure from the calculated saturated water vapor pressure. The formula for the actual water vapor pressure is:

[0096] e a = e s *(1 - HR m )

[0097] In the formula, HR m is the average relative humidity of the air, with the unit of %.

[0098] The slope of the water vapor pressure curve usually refers to the rate of change of water vapor pressure with temperature. Then, the slope of the water vapor pressure curve can be obtained by taking the derivative of the actual water vapor pressure with respect to temperature. All the meteorological parameters used for calculating the water evaporation amount are meteorological data within the day. Specifically, the meteorological data of the current day can be estimated by collecting the historical meteorological data of the meteorological station in this sub-region.

[0099] According to the obtained water evaporation amount, combined with the maximum water-bearing volume and meteorological parameters in each sub-region, calculate and generate an evaporation potential index. The formula for calculating the evaporation potential index is as follows:

[0100]

[0101] In the formula, SCI is the evaporation potential index, HR m is the average relative humidity of the air, and A is the maximum water-bearing volume.

[0102] It should be noted that the evaporation potential index SCI is used to characterize the water collection capacity of a city. The larger its value, the faster the water evaporates in the city. When large-scale rainfall occurs, the probability of urban flood and waterlogging is smaller, that is, the city's ability to withstand rainfall is stronger.

[0103] Among them, the soil water evaporation ET0 is determined by meteorological factors (such as temperature, wind speed, radiation, etc.), indicating the maximum possible evaporation under specific meteorological conditions. The larger its value, the more water evaporates. Therefore, it improves the city's water collection capacity. So, the soil water evaporation ET0 is directly proportional to the evaporation potential index SCI. The use of [placeholder] means that the relationship between evaporation potential and reference evaporation is non-linear. The increase in evaporation is not simply linear. When the reference evaporation is greater than a certain value, the evaporation potential will increase significantly. This non-linear relationship can better reflect the complexity in the actual evaporation process.

[0104] The maximum water-bearing volume A of the water body. The larger its value, the more water it can hold. Therefore, the city's water collection capacity is stronger. So, the maximum water-bearing volume A of the water body is directly proportional to the evaporation potential index SCI. A It means that the influence of the water body volume on the evaporation potential is significant. The larger the water body volume, the more water it can store.

[0105] The maximum water-bearing volume A of the water body refers to the maximum amount of water that the water bodies (such as lakes, rivers, artificial reservoirs, etc.) in the corresponding sub-region can store under specific conditions. The specific method for obtaining this parameter is as follows: For water bodies with regular shapes, the maximum volume can be calculated through conventional volume calculation formulas. For water bodies with irregular shapes, the depth and area data obtained through measurement are usually used, and the volume is estimated through numerical integration or hydrological models. A hydrological model (such as a lake model or a hydrological cycle model) is used to calculate the capacity of the water body, or remote sensing technology is used to obtain the surface area and water depth data of the water body for capacity calculation. According to the volumes of the water bodies with regular and irregular shapes in the obtained sub-region, the volumes of the water bodies with regular and irregular shapes are accumulated to obtain the maximum water-bearing volume A of the water body in this sub-region.

[0106] Average relative air humidity HR m is one of the important factors affecting evaporation. When the relative humidity is low, the air can take away more water, promoting evaporation; on the contrary, when the relative humidity is high, evaporation is inhibited. Therefore, placing HR m in the denominator reflects its negative impact on the evaporation potential.

[0107] Temperature is usually directly proportional to the evaporation rate. The higher the temperature, the greater the evaporation potential usually is. Therefore, T m is directly proportional to the evaporation potential index SCI.

[0108] The terrain factor analysis module is used to calculate and generate the urban water collection capacity evaluation coefficient based on the obtained accurate values of the evaporation potential index and the soil water holding capacity index. At the same time, it obtains the average ground slope angle of each sub-region and corrects the urban water collection capacity evaluation coefficient according to the average ground slope angle to obtain the accurate value of the urban water collection capacity evaluation coefficient.

[0109] Based on the obtained accurate values of the evaporation potential index and the soil water holding capacity index, calculate and generate the urban water collection capacity evaluation coefficient. The formula for calculating the urban water collection capacity evaluation coefficient is as follows:

[0110] ZH = ω1 * SCI 2 + ω2 * ln(1 + ECI′)

[0111] In the formula, ZH is the urban water collection capacity evaluation coefficient, ω1 and ω2 are the weight coefficients of the accurate values of the evaporation potential index and the soil water holding capacity index respectively, where ω1 ≤ ω2 and both ω1 and ω2 are greater than 0;

[0112] Among them, the above shows that the accurate values of the evaporation potential index and the soil water holding capacity index are both proportional to the urban water collection capacity evaluation coefficient ZH, which will not be elaborated here. Among them, SCI in the form of a square indicates that as the evaporation potential index increases, the urban water collection capacity evaluation coefficient increases significantly. The logarithmic function ln(1 + ECI′) indicates that as the accurate value of the soil water holding capacity index increases, the influence on the urban water collection capacity evaluation coefficient ZH gradually decreases.

[0113] Among them, the water holding capacity of the soil plays a more fundamental role in urban water resource management because it directly determines how much water the soil can store and retain, thus affecting the urban water supply and utilization. Since the soil water holding capacity directly affects the water storage capacity of the city after rainfall, its influence on the water collection capacity evaluation is higher than that of the evaporation potential. Even if the evaporation potential is large, if the soil water holding capacity is weak, the urban water collection capacity will still be limited. Therefore, ω1 ≤ ω2 and both ω1 and ω2 are greater than 0 are designed.

[0114] Correct the urban water collection capacity evaluation coefficient according to the average ground slope angle to obtain the accurate value of the urban water collection capacity evaluation coefficient. The formula for calculating the accurate value of the urban water collection capacity evaluation coefficient is as follows:

[0115] ZH′ = ZH * (1 + sinθ)

[0116] In the formula, θ is the average ground slope angle, and the average ground slope angle specifically refers to the average value of the angle between the land of the sub-region and the horizontal plane.

[0117] Among them, the larger the average ground slope angle is, the higher the terrain is. Since water flows towards lower places, the probability of being eroded by accumulated water becomes smaller. Therefore, the average ground slope angle is directly proportional to the urban water collection capacity evaluation coefficient, and the proportional relationship is represented by sinθ.

[0118] The water collection capacity evaluation module is used to obtain the average rainfall and the real-time average soil humidity of the urban area to be evaluated, dynamically correct the pre-set water collection capacity evaluation threshold according to the average rainfall and the real-time average soil humidity to obtain the corrected value of the water collection capacity evaluation threshold, compare the accurate value of the urban water collection capacity evaluation coefficient with the corrected value of the water collection capacity evaluation threshold, and generate the corresponding urban water collection capacity evaluation result according to the obtained comparison result.

[0119] Compare the accurate value of the urban water collection capacity evaluation coefficient with the corrected value of the water collection capacity evaluation threshold, and generate the corresponding urban water collection capacity evaluation result according to the obtained comparison result. The specific judgment logic is as follows:

[0120] When ZH′≥1.0*yz, it is judged that the water collection capacity of this sub-region is high, indicating that this sub-region can collect and discharge rainwater, reducing the risk of urban waterlogging.

[0121] When 0.4*yz≤ZH′<1.0*yz, it is judged that the water collection capacity of this sub-region is medium, indicating that there is a risk of urban waterlogging in this sub-region under extreme rainfall conditions.

[0122] When 0≤ZH′<0.4*yz, it is judged that the water collection capacity of this sub-region is low, indicating that there are serious waterlogging problems in this sub-region in the face of rainfall, and improvement measures should be taken in time.

[0123] Among them, yz is the corrected value of the water collection capacity evaluation threshold, and the specific formula for calculation is as follows:

[0124]

[0125] In the formula, yz0 is the pre-set water collection capacity evaluation threshold, Rz is the average rainfall, specifically the average monthly rainfall, HR S is the current average soil humidity, HR0 is the reference humidity, and Rz0 is the reference rainfall, where Rz0>Rz.

[0126] Among them, the greater the average rainfall, the more waterlogging the city faces. When the average rainfall is closer to the reference rainfall, it indicates that the rainfall in the city is greater and the risk of waterlogging is higher. The greater the current average soil humidity, the weaker the water-holding capacity of the soil. Therefore, the average rainfall is proportional to the correction value of the water collection capacity evaluation threshold, and the difference between the average soil humidity and the reference humidity is proportional to the correction value of the water collection capacity evaluation threshold. When the average rainfall is greater, the threshold should be increased to avoid missed risk judgments. When the difference between the average soil humidity and the reference humidity is positive, it indicates that the average soil humidity is too high and the water-holding capacity is weakened, and the threshold is correspondingly increased; otherwise, the threshold is correspondingly decreased. Among them, the reference humidity HR0 is generally 25% to 40%, and the reference rainfall Rz0 can be set according to the specific rainfall in the city, such as being set to twice the maximum monthly rainfall.

[0127] Please refer to Figure 2 , the present invention also provides a method for evaluating the urban water collection capacity based on ecological data analysis. The method for evaluating the urban water collection capacity based on ecological data analysis is used to control the above-mentioned system for evaluating the urban water collection capacity based on ecological data analysis. The specific steps include:

[0128] Step 1: Divide the area of the urban area to be evaluated into several sub-regions with equal areas, and collect the soil characteristic information in each sub-region simultaneously for multiple times. Based on the soil characteristic information, calculate the soil water-holding capacity index. The soil characteristic information includes the average soil particle size, the average field water-holding capacity of the soil, and the average dry density of the soil;

[0129] Step 2: Obtain the average vegetation coverage density and soil permeability of each sub-region. According to the obtained average vegetation coverage density and soil permeability, correct the soil water-holding capacity index of the corresponding sub-region to obtain the accurate value of the soil water-holding capacity index;

[0130] Step 3: Collect the maximum water-carrying volume and meteorological parameters in each sub-region. Based on the meteorological parameters in each sub-region, calculate the water evaporation amount of the corresponding sub-region. According to the obtained water evaporation amount, combined with the maximum water-carrying volume and meteorological parameters in each sub-region, calculate and generate an evaporation potential index. The meteorological parameters include air humidity, air temperature, and wind speed;

[0131] Step 4: Based on the obtained evaporation potential index and the accurate value of the soil water-holding capacity index, calculate and generate an urban water collection capacity evaluation coefficient. At the same time, obtain the average ground slope angle of each sub-region, and correct the urban water collection capacity evaluation coefficient according to the average ground slope angle to obtain the accurate value of the urban water collection capacity evaluation coefficient;

[0132] Step 5: Obtain the average rainfall in the urban area to be evaluated and the average soil humidity in real time. Dynamically correct the preset water collection capacity evaluation threshold according to the average rainfall and the average soil humidity in real time to obtain the corrected value of the water collection capacity evaluation threshold. Compare the accurate value of the urban water collection capacity evaluation coefficient with the corrected value of the water collection capacity evaluation threshold, and generate the corresponding urban water collection capacity evaluation result according to the obtained comparison result.

[0133] The above formulas are all dimensionless and take their numerical values for calculation. The formulas are obtained by collecting a large amount of data for software simulation to get a formula closest to the actual situation. The preset parameters in the formulas are set by those skilled in the art according to the actual situation.

[0134] The above embodiments can be implemented in whole or in part by software, hardware, firmware or any other combination. When implemented using software, the above embodiments can be implemented in whole or in part in the form of a computer program product. Those skilled in the art can realize that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are executed by hardware or software methods depends on the specific application and design constraints of the technical solution.

[0135] The units described as separate components may or may not be physically separated. The components shown as units may or may not be physical units, and may be located in one place, or may be distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0136] The above is only the specific implementation manner of this application, but the protection scope of this application is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed in this application, and all should be covered by the protection scope of this application.

Claims

1. A system for evaluating urban water collection capacity based on ecological data analysis, characterized in that: Specifically include: A soil information collection module is used to divide the urban area to be evaluated into several sub-areas, and collect soil characteristic information in each sub-area multiple times at the same time, and calculate the soil water holding capacity index based on the soil characteristic information, wherein the soil characteristic information includes the average soil particle size, the average soil field water holding capacity and the average dry density of the soil; The water holding capacity analysis module is used to obtain the average vegetation coverage density and soil permeability of each sub-area. According to the obtained average vegetation coverage density and soil permeability, the soil water holding capacity index of the corresponding sub-area is corrected to obtain the accurate value of the soil water holding capacity index; An evaporation potential analysis module is used to collect the maximum carrying volume of water bodies and meteorological parameters in each sub-region, calculate the water evaporation amount of the corresponding sub-region based on the meteorological parameters in each sub-region, and calculate and generate an evaporation potential index based on the obtained water evaporation amount and the maximum carrying volume of water bodies and meteorological parameters in each sub-region, wherein the meteorological parameters include air humidity, air temperature and wind speed; The terrain factor analysis module is used to calculate the urban water collection capacity evaluation coefficient using the obtained evaporation potential index and soil water holding capacity index, and obtain the average ground slope angle of each sub-area. The urban water collection capacity evaluation coefficient is corrected according to the average ground slope angle to obtain the accurate value of the urban water collection capacity evaluation coefficient; The water collection capacity assessment module is used to obtain the average rainfall and real-time average soil moisture in the urban area to be assessed, dynamically correct the preset water collection capacity assessment threshold according to the average rainfall and the real-time average soil moisture, obtain the water collection capacity assessment threshold correction value, compare the precise value of the urban water collection capacity assessment coefficient with the water collection capacity assessment threshold correction value, and generate the corresponding urban water collection capacity assessment result based on the comparison result.

2. The urban water collection capacity assessment system based on ecological data analysis according to claim 1 is characterized by: The specific method for collecting soil characteristic information in each sub-area in real time and multiple times simultaneously includes: dividing the urban area to be evaluated into m sub-areas of equal area, collecting soil samples at different depths, and analyzing the collected soil samples to obtain soil characteristic information, wherein the depth range for collecting soil samples includes: 0-10cm, 10-20cm, 20-30cm, 30-40cm and 40-50cm, and the collection method is: randomly collecting one soil in each depth range of the sub-area, obtaining the values ​​of each parameter of its soil characteristic information, calculating the average value of the soil characteristic information at 5 different depths, and using this average value as the soil characteristic information of the sub-area, including the average soil particle size, the average soil field water holding capacity and the average soil dry density.

3. The urban water collection capacity assessment system based on ecological data analysis according to claim 2 is characterized by: The soil water holding capacity index is calculated based on soil characteristic information, and the specific formula for calculating the soil water holding capacity index is: In the formula, ECI is the soil water holding capacity index, BD is the average dry density of the soil, HC is the average field water holding capacity of the soil, and D mean is the average soil particle size; According to the average vegetation coverage density and soil permeability, the soil water holding capacity index of the corresponding sub-region is corrected to obtain the precise value of the soil water holding capacity index. The formula for calculating the precise value of the soil water holding capacity index is: Where ECI′ is the exact value of the soil water holding capacity index, VC is the average vegetation cover density, and K is the soil permeability.

4. The urban water collection capacity assessment system based on ecological data analysis according to claim 3 is characterized by: The specific method for obtaining the soil permeability K is as follows: select the soil sample to be tested and place it in a cylindrical permeameter. The sample must be fully saturated before being placed in the cylindrical permeameter. Set a constant water level difference, that is, maintain a constant height difference between the water source of the permeameter and the water level above the soil sample. In the time period t, record the amount of water flowing through the soil sample, and calculate the soil permeability based on the recorded data. The specific formula for calculating the soil permeability K is: Where Q is the amount of water flowing through the soil sample in time period t, L is the thickness of the soil sample in the permeameter, PF is the cross-sectional area of ​​the soil sample in the permeameter, and h is the set water level difference.

5. The urban water collection capacity assessment system based on ecological data analysis according to claim 3 is characterized by: The maximum water carrying volume and meteorological parameters in each sub-area are collected, and the water evaporation of the corresponding sub-area is calculated based on the meteorological parameters in each sub-area. The formula for calculating the water evaporation is: In the formula, e s -e a is the saturated water vapor pressure difference, in kPa, the soil water evaporation is ET0, in mm, u n is the net radiation on the crop canopy surface, in MJm -2 d -1 ; G is soil heat flux, unit is MJm -2 d -1 ; γ is the hygrometer constant, unit is kPa℃ -1 , T m is the daily average air temperature in °C, V m is the daily average wind speed, in ms -1 , Δ is the slope of the water vapor pressure curve, in kPa℃ -1 ; According to the obtained water evaporation, combined with the maximum carrying volume of water bodies in each sub-area and meteorological parameters, the evaporation potential index is calculated. The formula for calculating the evaporation potential index is: Where SCI is the evaporation potential index, HR is m is the average relative humidity of air, and A is the maximum carrying volume of water body.

6. The urban water collection capacity assessment system based on ecological data analysis according to claim 5 is characterized by: Based on the obtained accurate values ​​of evaporation potential index and soil water holding capacity index, the urban water collection capacity assessment coefficient is calculated. The formula for calculating the urban water collection capacity assessment coefficient is: ZH=ω1*SCI 2 +ω2*ln(1+ECI′) Where ZH is the urban water collection capacity assessment coefficient, ω1 and ω2 are the weight coefficients of the exact values ​​of the evaporation potential index and the soil water holding capacity index, respectively, where ω1≤ω2 and ω1 and ω2 are both greater than 0; The urban water collection capacity assessment coefficient is corrected according to the average ground slope angle to obtain the precise value of the urban water collection capacity assessment coefficient. The formula for calculating the precise value of the urban water collection capacity assessment coefficient is: ZH′=ZH*(1+sinθ) Wherein, θ is the average ground slope angle, which specifically refers to the average value of the angle between the land in the sub-area and the horizontal plane.

7. The urban water collection capacity assessment system based on ecological data analysis according to claim 6 is characterized by: The precise value of the urban water collection capacity assessment coefficient is compared with the corrected value of the water collection capacity assessment threshold, and the corresponding urban water collection capacity assessment result is generated according to the comparison result. The specific judgment logic is as follows: When ZH′≥1.0*yz, the water collection capacity of the sub-region is judged to be high, indicating that the sub-region can collect and discharge rainwater, reducing the risk of urban waterlogging; When 0.4*yz≤ZH′<1.0*yz, the water collection capacity of the sub-region is judged to be medium, indicating that the sub-region is at risk of urban waterlogging under extreme rainfall conditions; When 0≤ZH′<0.4*yz, the water collection capacity of the sub-region is judged to be low, indicating that the sub-region has serious waterlogging problems when facing rainfall, and improvement measures should be taken in time; Where yz is the threshold correction value for water collection capacity assessment, and the specific calculation formula is: Where yz0 is the pre-set water collection capacity assessment threshold, Rz is the average rainfall, specifically the average monthly rainfall, HR S is the current average soil moisture, HR0 is the reference humidity, Rz0 is the reference rainfall, where Rz0>Rz.

8. A method for evaluating urban water collection capacity based on ecological data analysis, characterized in that: The method for evaluating urban water collection capacity based on ecological data analysis is used to control the system for evaluating urban water collection capacity based on ecological data analysis according to any one of claims 1 to 7, and the specific steps include: Divide the urban area to be evaluated into several sub-areas, collect soil characteristic information in each sub-area multiple times, and calculate the soil water holding capacity index based on the soil characteristic information, wherein the soil characteristic information includes the average soil particle size, the average soil field water holding capacity and the average dry density of the soil; The average vegetation coverage density and soil permeability of each sub-region are obtained, and the soil water holding capacity index of the corresponding sub-region is corrected according to the obtained average vegetation coverage density and soil permeability to obtain the accurate value of the soil water holding capacity index; The maximum carrying volume of water bodies and meteorological parameters in each sub-region are collected, and the water evaporation amount of the corresponding sub-region is calculated based on the meteorological parameters in each sub-region. According to the obtained water evaporation amount, the maximum carrying volume of water bodies and meteorological parameters in each sub-region are combined to calculate and generate an evaporation potential index, wherein the meteorological parameters include air humidity, air temperature and wind speed; Based on the obtained accurate values ​​of the evaporation potential index and the soil water holding capacity index, the urban water collection capacity assessment coefficient is calculated and generated. At the same time, the average ground slope angle of each sub-area is obtained, and the urban water collection capacity assessment coefficient is corrected according to the average ground slope angle to obtain the accurate value of the urban water collection capacity assessment coefficient; The average rainfall and real-time average soil moisture of the urban area to be evaluated are obtained, and the preset water collection capacity assessment threshold is dynamically corrected according to the average rainfall and the real-time average soil moisture to obtain the water collection capacity assessment threshold correction value, and the precise value of the urban water collection capacity assessment coefficient is compared with the water collection capacity assessment threshold correction value, and the corresponding urban water collection capacity assessment result is generated according to the comparison result.

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