Sea-entering estuary nitrogen pollution monitoring method and system based on coupling model

Abstract

The invention provides a coupling model-based sea-entering estuary nitrogen pollution monitoring method and a coupling model-based sea-entering estuary nitrogen pollution monitoring system. The method comprises the following steps of obtaining a surface water body nitrogen pollution amount of a target drainage basin; obtaining the underground water nitrogen pollution amount of the target drainage basin; adding the surface water body nitrogen pollution amount and the underground water body nitrogen pollution amount to obtain the estuary nitrogen pollution amount of the sea-entering river channel of the target drainage basin; acquiring nitrogen pollution associated feature data of the target drainage basin, and calculating a nitrogen pollution contribution value corresponding to the nitrogen pollution associated feature data according to the estuary nitrogen pollution amount of the sea-entering river channel of the target drainage basin; and performing nitrogen pollution monitoring on the target drainage basin according to the nitrogen pollution contribution value corresponding to each piece of nitrogen pollution associated feature data in combination with a preset sea-entering estuary water quality monitoring criterion. Therefore, by applying the technical scheme of the application, the nitrogen pollution monitoring efficiency and the environment management and pollution treatment efficiency of the river mouth entering the sea can be effectively improved.

Description

Technical Field

[0001] The present application relates to the field of nitrogen pollution monitoring, and in particular to a method and system for monitoring nitrogen pollution in estuaries based on a coupling model. Background Art

[0002] River basins are home to large populations, and human activities significantly impact river water quality. As river basin governance efforts continue to advance, nitrogen pollution is becoming increasingly prominent. This, coupled with the increasing pressure from agricultural production and industrial development within the basin, necessitates monitoring and effective control of nitrogen pollution.

[0003] However, in the existing technology, when evaluating the nitrogen pollution load of estuaries, only a single source is usually considered, resulting in omissions and underestimations, thereby affecting the efficiency of nitrogen pollution monitoring, environmental management and pollution control in estuaries. Summary of the Invention

[0004] Based on this, the purpose of this application is to provide a method and system for monitoring nitrogen pollution in river estuaries based on a coupling model, which can effectively improve the efficiency of nitrogen pollution monitoring in river estuaries as well as the efficiency of environmental management and pollution control.

[0005] The purpose of this application can be achieved through the following technical solutions:

[0006] A method for monitoring nitrogen pollution at sea estuaries based on a coupling model comprises the following steps: obtaining the nitrogen pollution amount of surface water bodies in a target river basin, wherein the target river basin includes several sea-entering rivers, and the nitrogen pollution amount of surface water bodies is the total nitrogen load of surface water in the target river basin input into the sea-entering rivers; obtaining the nitrogen pollution amount of groundwater bodies in the target river basin, wherein the nitrogen pollution amount of groundwater bodies is the total nitrogen load of groundwater in the target river basin input into the sea-entering rivers; adding the nitrogen pollution amount of surface water bodies to the nitrogen pollution amount of groundwater bodies to obtain the nitrogen pollution amount at the estuary of the sea-entering river in the target river basin; obtaining nitrogen pollution correlation characteristic data of the target river basin, and calculating the nitrogen pollution contribution value corresponding to the nitrogen pollution correlation characteristic data according to the nitrogen pollution amount at the estuary of the sea-entering river in the target river basin; and performing nitrogen pollution monitoring on the target river basin according to the nitrogen pollution contribution value corresponding to each of the nitrogen pollution correlation characteristic data and in combination with preset sea-entering river estuary water quality monitoring criteria.

[0007] A nitrogen pollution monitoring system for estuaries entering the sea based on a coupling model, wherein the nitrogen pollution monitoring system for estuaries entering the sea comprises: a surface water nitrogen pollution amount acquisition unit, used to acquire the surface water nitrogen pollution amount of a target basin, wherein the target basin includes several rivers entering the sea, and the surface water nitrogen pollution amount is the total nitrogen load of the surface water in the target basin input into the rivers entering the sea; a groundwater nitrogen pollution amount acquisition unit, used to acquire the groundwater nitrogen pollution amount of the target basin, wherein the groundwater nitrogen pollution amount is the total nitrogen load of the groundwater in the target basin input into the rivers entering the sea ; An estuary nitrogen pollution amount acquisition unit is used to add the nitrogen pollution amount of the surface water body and the nitrogen pollution amount of the groundwater body to obtain the estuary nitrogen pollution amount of the sea-entering river in the target river basin; a nitrogen pollution contribution value acquisition unit is used to obtain the nitrogen pollution correlation characteristic data of the target river basin, and calculate the nitrogen pollution contribution value corresponding to the nitrogen pollution correlation characteristic data based on the estuary nitrogen pollution amount of the sea-entering river in the target river basin; a nitrogen pollution monitoring unit is used to monitor nitrogen pollution in the target river basin based on the nitrogen pollution contribution value corresponding to each of the nitrogen pollution correlation characteristic data, combined with the preset sea-entering river estuary water quality monitoring criteria.

[0008] Compared with the existing technology, the method described in this application first obtains the total nitrogen load of surface water bodies input into the river channel entering the sea in the target basin as the surface water body nitrogen pollution amount and the total nitrogen load of groundwater bodies input into the river channel entering the sea as the groundwater body nitrogen pollution amount, and adds the two to obtain the estuary nitrogen pollution amount of the river channel entering the sea. Then, the nitrogen pollution correlation characteristic data of the target basin is obtained, and the nitrogen pollution contribution value corresponding to these correlation characteristic data is determined according to the calculated estuary nitrogen pollution amount, which clearly reveals the relative impact of each related pollution factor on the total nitrogen pollution at the estuary, and finally guides nitrogen pollution monitoring based on the corresponding contribution value and the preset estuary water quality monitoring criteria. Therefore, the method described in this application realizes a comprehensive quantitative assessment of both surface and underground pollution sources, overcomes the omission and underestimation problems caused by the conventional technology of only considering a single source when assessing the total nitrogen pollution load in estuaries, and also realizes the quantification of the contribution values ​​of various related factors affecting nitrogen pollution in estuaries, so that subsequent nitrogen pollution monitoring can be more targeted and efficiently deployed and optimized based on the actual contribution of the pollution source, effectively improving the scientificity and accuracy of nitrogen pollution monitoring in estuaries, and improving the efficiency of nitrogen pollution monitoring in estuaries as well as environmental management and pollution control.

[0009] For better understanding and implementation, the present application is described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 A flow chart of a method for monitoring nitrogen pollution in estuaries based on a coupled model provided in this application;

[0011] Figure 2 A flowchart of the steps for obtaining the nitrogen pollution level of surface water bodies in a target basin in a method for monitoring nitrogen pollution in estuaries based on a coupling model provided in this application;

[0012] Figure 3 A flowchart of the steps for obtaining the nitrogen pollution level of groundwater in the target basin in a method for monitoring nitrogen pollution in an estuary based on a coupling model provided in this application;

[0013] Figure 4 A flowchart of the steps for obtaining nitrogen pollution correlation characteristic data of the target watershed in a method for monitoring nitrogen pollution in an estuary based on a coupling model provided in this application;

[0014] Figure 5 This is a structural principle diagram of a nitrogen pollution monitoring system for estuaries based on a coupling model provided in this application. DETAILED DESCRIPTION

[0015] This application provides a method and system for monitoring nitrogen pollution in river estuaries based on a coupled model. To clarify the purpose, technical solutions, and effects of this application, the application is further described below with reference to the accompanying drawings and examples. It should be understood that the specific examples described herein are intended only to illustrate this application and are not intended to limit it.

[0016] It will be understood by those skilled in the art that, unless expressly stated otherwise, the singular forms "a", "an", "said" and "the" used herein may also include the plural forms. It should be further understood that the term "comprising" used in the specification of the present application refers to the presence of the features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof. It should be understood that when we refer to an element as being "connected" or "coupled" to another element, it may be directly connected or coupled to the other element, or there may be intermediate elements. In addition, "connected" or "coupled" as used herein may include wireless connections or wireless couplings. The term "and / or" used herein includes all or any units and all combinations of one or more associated listed items.

[0017] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with their meanings in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless specifically defined as herein.

[0018] The invention will be further explained below through description of embodiments in conjunction with the accompanying drawings.

[0019] Example 1

[0020] Please refer to Figure 1 , Figure 1 This application provides a flow chart of a method for monitoring nitrogen pollution in estuaries based on a coupled model. The method includes the following steps:

[0021] S10. Obtain nitrogen pollution levels in surface water bodies of the target watershed;

[0022] S20, obtaining the nitrogen pollution level of the groundwater in the target watershed;

[0023] S30, adding the nitrogen pollution amount of the surface water body to the nitrogen pollution amount of the groundwater body to obtain the nitrogen pollution amount of the estuary of the river flowing into the sea in the target basin;

[0024] S40, obtaining nitrogen pollution correlation characteristic data of the target watershed, and calculating a nitrogen pollution contribution value corresponding to the nitrogen pollution correlation characteristic data based on the nitrogen pollution amount at the estuary of the river flowing into the sea in the target watershed;

[0025] S50: Perform nitrogen pollution monitoring on the target watershed according to the nitrogen pollution contribution values ​​corresponding to the nitrogen pollution associated characteristic data and in combination with preset sea estuary water quality monitoring criteria.

[0026] Compared with the existing technology, the technical solution of the present application obtains the total nitrogen load of surface water bodies input into the river channel entering the sea in the target basin as the surface water body nitrogen pollution amount and the total nitrogen load of groundwater bodies input into the river channel entering the sea as the groundwater body nitrogen pollution amount, and adds the two to obtain the estuary nitrogen pollution amount of the river channel entering the sea, thereby achieving a comprehensive quantitative assessment of both surface and underground pollution sources, overcoming the omission and underestimation problems caused by the existing technology that usually only considers a single source when evaluating the total nitrogen pollution load of the estuary entering the sea. On this basis, the technical solution of the present application further obtains the nitrogen pollution correlation characteristic data of the target basin, determines the nitrogen pollution contribution value corresponding to these correlation characteristic data according to the calculated estuary nitrogen pollution amount, clearly reveals the relative impact of each related pollution factor on the total nitrogen pollution in the estuary, and finally guides the nitrogen pollution monitoring based on the corresponding contribution value and the preset estuary water quality monitoring criteria. Therefore, the technical solution of this application not only provides more comprehensive and accurate data on the total nitrogen pollution load in estuaries, but also realizes the quantification of the contribution values ​​of various related factors affecting nitrogen pollution in estuaries, so that subsequent nitrogen pollution monitoring can be more targeted and efficiently deployed and optimized based on the actual contribution of pollution sources, effectively improving the scientificity and accuracy of nitrogen pollution monitoring in estuaries entering the sea, and improving the efficiency of nitrogen pollution monitoring in estuaries entering the sea, as well as the efficiency of environmental management and pollution control.

[0027] In step S10, the nitrogen pollution level of the surface water in the target watershed is obtained.

[0028] Wherein, the target watershed includes several rivers flowing into the sea, and the nitrogen pollution amount of the surface water is the total nitrogen load input from the surface water in the target watershed to the rivers flowing into the sea;

[0029] Please refer to Figure 2 In one embodiment, step S10 includes the following steps:

[0030] S101. Calculate the organic nitrogen load ORGN of the surface water in the target watershed input into the river vent into the sea according to the organic nitrogen pollution load calculation formula:

[0031]

[0032] Among them, ρ orgN is the organic nitrogen concentration at 10 mm above the soil surface in the target watershed, m is the soil loss in the target watershed, A is the area of ​​the target watershed, ε N is the nitrogen enrichment factor of the target watershed.

[0033] In one embodiment, a person skilled in the art can collect soil samples at a depth of 10 mm on the soil surface at multiple sampling points in the target watershed using a depth-limiting ring knife or a scraper, and then measure the organic nitrogen concentration at 10 mm on the soil surface in the target watershed by applying chemical treatment methods such as the Kjeldahl method; at the same time, in other alternative embodiments, based on the inventive concept of the present application, a person skilled in the art can also obtain the organic nitrogen concentration at 10 mm on the soil surface in the target watershed by other means to continue to implement the remaining steps of the method for monitoring nitrogen pollution in estuaries described in the present application.

[0034] In one embodiment, a person skilled in the art can set up a standard runoff plot with a collecting trough on the inner slope farmland of the target watershed, and measure the amount of runoff sediment after a rainstorm; simultaneously use drone mapping to generate a high-precision DEM, combine the K value measured by on-site soil sampling, run the RUSLE model and correct the LS / C / P factor through the runoff plot data, and finally output a spatial distribution soil loss map (when the accuracy requirement is low, a steel drill can be used to measure the exposed height of the erosion nail to quickly calculate), and the soil loss amount of the target watershed can be measured; similarly, a person skilled in the art can use the standard runoff plot outlet in the target watershed to obtain the soil loss amount of the target watershed. The sediment settled after the rainstorm is collected at a certain location, the organic nitrogen concentration in the sediment is measured, and the organic nitrogen concentration of the original surface soil (0-10 mm) in the cell is simultaneously collected. The nitrogen enrichment coefficient of the target watershed can be directly calculated through EN (nitrogen enrichment coefficient) = ρ sediment N / ρ soil N; at the same time, in other alternative embodiments, based on the inventive concept of the present application, those skilled in the art can also obtain the soil loss amount of the target watershed or the nitrogen enrichment coefficient of the target watershed by other means to continue to implement the remaining steps of the estuary nitrogen pollution monitoring method described in the present application.

[0035] S102. Calculate the nitrate nitrogen load NSURQ of the surface water in the target watershed inputted into the river venturing into the sea according to the nitrate nitrogen pollution load calculation formula:

[0036]

[0037] Among them, ρ NO3ly is the content of nitrate nitrogen in the soil in the target basin, W surf is the amount of surface water retained in the soil layer in the target basin, θ e is the porosity of the target basin, SAT ly is the content of saturated water in the soil in the target watershed.

[0038] In one embodiment, those skilled in the art can measure the content of nitrate nitrogen in the soil of the target watershed by adopting dual-wavelength spectrophotometry, specifically comprising: first using a stainless steel soil drill to obtain a soil sample at a depth of 0-20 cm in the target watershed, removing the gravel and roots, and immediately placing the fresh sample in an ice box (stored at 4°C for ≤24h); then adding deionized water to the fresh sample at a ratio of soil:water = 1:5, shaking for 30 minutes and then filtering, adding sulfonamide solution and naphthylethylenediamine hydrochloride solution to the filtrate, and reacting in the dark for 10 minutes to generate a pink complex; finally using an ultraviolet spectrophotometer to measure the absorbance at dual wavelengths of 540nm and 700nm, and calculating against the standard curve to obtain the result.

[0039] In one embodiment, those skilled in the art can measure the retention of surface water in the soil layer in the target watershed by the double-ring infiltration in situ measurement method, which specifically includes: first, selecting a sample plot in the target watershed, and vertically pressing a double-ring sleeve with a diameter of 20 cm (inner ring) and 50 cm (outer ring) into the ground surface at a depth of 5 cm; then, simultaneously injecting clean water into the inner and outer rings, maintaining a water depth of 3 cm in the inner ring and 5 cm in the outer ring (to prevent lateral seepage); finally, recording the water level drop value Δh of the inner ring every 5 minutes, and continuously measuring until Δh is constant, and calculating it through retention amount = infiltration amount per unit time × rainfall duration.

[0040] In one embodiment, those skilled in the art can measure the porosity of the target basin by a constant volume resampler method, specifically comprising: using a 100 cm 3 The ring cutter is driven vertically into the soil layer of the target basin, and the ends are flattened after being taken out, and the weight of the ring cutter + wet soil (W) is measured; it is dried in a 105°C oven to constant weight, and the weight of the ring cutter + dry soil (W) is measured; finally, the porosity can be calculated by soil bulk density = (W-ring cutter weight) / 100 and porosity = (1-soil bulk density / 2.65)×100%, where 2.65 is the empirical value of soil specific gravity.

[0041] In one embodiment, a person skilled in the art can place a filter paper on the bottom of a ring cutter filled with undisturbed soil taken from the target watershed, immerse it in shallow water to 2 / 3 of its height, and wait for 48 hours until it is completely saturated. Then, the ring cutter is taken out and the surface is wiped dry. The saturated soil weight (W) is weighed, and finally the saturated water content in the soil of the target watershed can be calculated by saturated water content = (WW) / (W-ring cutter weight) × 100%, where W is the dry soil weight.

[0042] In other alternative embodiments, based on the inventive concept of the present application, those skilled in the art may also obtain the above-mentioned nitrate nitrogen content in the soil of the target watershed, the retention of surface water in the soil layer in the target watershed, the porosity of the target watershed or the saturated water content in the soil in the target watershed by other means to continue to implement the remaining steps of the estuary nitrogen pollution monitoring method described in the present application.

[0043] In one embodiment, when the target watershed includes several farmland areas, technicians in this field need to avoid measuring the above parameters within 7 days after fertilization (to avoid the impact of nitrogen fertilizer); similarly, if the target watershed is in extreme weather, technicians in this field need to wait for several days before measuring (such as sampling immediately after a rainstorm, which may dilute the concentration).

[0044] S103: Construct a watershed hydrological model to obtain nitrogen pollution TN of the surface water in the target watershed:

[0045] TN=ORGN+NSURQ,

[0046] Among them, TN is the nitrogen pollution amount of the surface water in the target basin, ORGN is the organic nitrogen load of the surface water in the target basin input into the river estuary, and NSURQ is the nitrate nitrogen load of the surface water in the target basin input into the river estuary.

[0047] In step S20, the nitrogen pollution level of the groundwater in the target watershed is obtained.

[0048] The nitrogen pollution amount of the groundwater body is the total nitrogen load of the groundwater in the target basin input into the river into the sea.

[0049] Please refer to Figure 3 In one embodiment, step S20 includes the following steps:

[0050] S201. Obtain a groundwater sample from the target basin and perform nitrogen digestion to obtain a digestion solution.

[0051] S202, calculating the total nitrogen concentration C of the groundwater in the target basin according to the digestion solution and the calculation formula of the total nitrogen concentration of groundwater TN ;

[0052]

[0053] Among them, C TN is the total nitrogen concentration of groundwater in the target basin, A 220 A is the absorbance of the digestion solution measured at a light wavelength of 220 nm. 275 is the absorbance of the digestion solution measured at a light wavelength of 275 nm, D is the dilution multiple of the digestion solution, V is the volume of the digestion solution, and V sample is the volume of the groundwater sample in the target basin, ε is the preset slope of the calibration curve, and L is the optical path of the cuvette.

[0054] S203. Obtain the nitrogen pollution amount of the groundwater in the target watershed according to the total nitrogen concentration of the groundwater in the target watershed.

[0055] In this embodiment, step S201 includes:

[0056] S2011. Monitoring wells are set at preset intervals in the target basin, and groundwater samples of several target basins are obtained from the flow path of the groundwater in the target basin. The groundwater samples are mixed to obtain groundwater samples of the target basin.

[0057] In one embodiment, based on the inventive concept of the present application, those skilled in the art may deploy monitoring wells near pollution sources and at key nodes of the groundwater flow path (such as infiltration areas or discharge areas). For example, three monitoring wells may be deployed upstream and downstream of the farmland area of ​​the target basin to obtain groundwater samples of the target basin respectively.

[0058] S2012. Add an alkaline potassium persulfate solution to the groundwater sample of the target watershed, and digest it at 120 degrees Celsius for 30 minutes to oxidize the organic nitrogen and nitrite nitrogen in the groundwater sample of the target watershed into nitrate nitrogen, thereby obtaining a digestion solution.

[0059] In other alternative embodiments, based on the inventive concept of the present application, those skilled in the art may also use satellite or UAV remote sensing images (such as Landsat8 images) combined with ground measured data to invert and obtain the total nitrogen concentration in the groundwater of the target basin; or, use a hydrogeochemical model (such as MODFLOW-MT3DMS) to simulate the groundwater flow and total nitrogen migration process, and output a concentration field to obtain the total nitrogen concentration in the groundwater of the target basin.

[0060] In this embodiment, step S203 includes:

[0061] S2031. Calculate the first groundwater nitrogen pollution amount UTN of the target basin according to the total nitrogen concentration of groundwater in the target basin and the calculation formula of groundwater nitrogen pollution amount:

[0062] UTN=C TN Q groundwater ,

[0063] Among them, UTN is the nitrogen pollution amount of the first groundwater body in the target basin, Q groundwater is the groundwater flow in the target basin.

[0064] In another embodiment, the nitrogen pollution amount UTN of the first groundwater body in the target watershed can also be obtained by: Calculated, where D is the diffusion coefficient of the target watershed.

[0065] S2032: Construct a groundwater recharge model to obtain the recharge volume Q of the surface water to the groundwater in the target basin. recharge :

[0066]

[0067] Among them, Q recharge is the surface water recharge to groundwater in the target basin, R i is the rainfall of the i-th sub-basin in the target basin, ET iis the evapotranspiration of the i-th sub-basin in the target basin, Q surf,i is the surface runoff of the i-th sub-basin in the target basin, and n is the number of sub-basins in the target basin.

[0068] S2033. Create a nitrogen migration coupling equation to obtain the nitrogen pollution UTN of the groundwater in the target basin. total :

[0069] UTN total =UTN+Q recharge -S decay ,

[0070] Among them, UTN total is the nitrogen pollution level of groundwater in the target basin, S decay is the nitrogen degradation amount of microorganisms in the target watershed.

[0071] In one embodiment, based on the inventive concept of the present application, those skilled in the art can measure the nitrogen degradation rate of the microorganisms in the target watershed by the in situ buried bag culture method in the "Soil Microbial Biomass Determination Method" NY / T 1847-2010, and then obtain the nitrogen degradation amount of the microorganisms in the target watershed.

[0072] In step S30, the nitrogen pollution amount of the surface water body is added to the nitrogen pollution amount of the groundwater body to obtain the nitrogen pollution amount at the estuary of the river flowing into the sea in the target basin.

[0073] In one embodiment, based on the inventive concept of this application, those skilled in the art calculate the nitrogen pollution amount TN of the surface water in the target basin in the current month and the nitrogen pollution amount UTN of the groundwater in the target basin in the current month. total By adding them together, the nitrogen pollution level at the estuary of the river entering the sea in the target basin in the current month can be obtained.

[0074] In step S40, nitrogen pollution correlation characteristic data of the target watershed is obtained, and a nitrogen pollution contribution value corresponding to the nitrogen pollution correlation characteristic data is calculated based on the nitrogen pollution amount at the estuary of the river flowing into the sea in the target watershed.

[0075] Please refer to Figure 4 In one embodiment, the step of obtaining the nitrogen pollution associated characteristic data of the target watershed includes:

[0076] S401. Acquire several items of remote sensing image feature data of the target watershed.

[0077] S402: Time-align each of the remote sensing image feature data with the nitrogen pollution level at the estuary of the river flowing into the sea in the target basin, and perform standardization:

[0078]

[0079] Wherein, X is the remote sensing image feature data, Y is the nitrogen pollution amount at the estuary of the river flowing into the sea in the target basin at the same time point corresponding to the remote sensing image feature data after time alignment, and X norm is the standardized data corresponding to the remote sensing image feature data, Y norm is the standardized data corresponding to the nitrogen pollution in the estuary, μX is the mean value of the remote sensing image feature data within the preset time period, μY is the mean value of the nitrogen pollution in the estuary within the preset time period, σX is the standard deviation of the remote sensing image feature data within the preset time period, and σY is the standard deviation of the nitrogen pollution in the estuary within the preset time period.

[0080] S403, calculating the Pearson correlation coefficient r between each of the remote sensing image feature data and the nitrogen pollution level at the estuary of the river flowing into the sea in the target basin:

[0081]

[0082] Wherein, n is the number of standardized data corresponding to the remote sensing image feature data and the number of standardized data corresponding to the nitrogen pollution amount at the estuary of the river entering the sea in the target basin, is the mean of the standardized data corresponding to the remote sensing image feature data, is the mean of the standardized data corresponding to the nitrogen pollution in the estuary, X i is the i-th standardized data corresponding to the remote sensing image feature data, Y i is the i-th standardized data corresponding to the nitrogen pollution in the estuary.

[0083] S404. If the Pearson correlation coefficient between the remote sensing image feature data and the nitrogen pollution amount at the estuary of the river flowing into the sea in the target river basin is greater than a preset threshold, it is determined that the remote sensing image feature data is strongly correlated with the nitrogen pollution amount at the estuary of the river flowing into the sea in the target river basin, and the corresponding remote sensing image feature data is the nitrogen pollution association feature data of the target river basin.

[0084] In one embodiment, if the absolute value of the Pearson correlation coefficient between the remote sensing image feature data and the nitrogen pollution amount at the estuary of the river flowing into the sea in the target river basin is greater than 0.5, it is determined that the remote sensing image feature data is strongly correlated with the nitrogen pollution amount at the estuary of the river flowing into the sea in the target river basin.

[0085] In this embodiment, a Pearson correlation coefficient greater than 0 indicates a positive correlation, and a Pearson correlation coefficient less than 0 indicates a negative correlation. However, those skilled in the art only need to focus on the absolute value of the Pearson correlation coefficient.

[0086] In another embodiment, those skilled in the art may also apply NMI normalized mutual information to test the nonlinear relationship between the remote sensing image feature data and the nitrogen pollution amount at the estuary of the river flowing into the sea in the target basin.

[0087] In one embodiment, the step of calculating the nitrogen pollution contribution value corresponding to the nitrogen pollution correlation characteristic data based on the nitrogen pollution amount at the estuary of the river flowing into the sea in the target watershed includes:

[0088] S405 : Calculate the nitrogen pollution amount corresponding to the nitrogen pollution correlation characteristic data according to the nitrogen pollution correlation characteristic data.

[0089] In one embodiment, the nitrogen pollution associated characteristic data includes at least agricultural activity data, industrial pollution data, livestock breeding data, and human life data.

[0090] In this embodiment, when the nitrogen pollution associated characteristic data is agricultural activity data (fertilization amount in farmland area), the corresponding nitrogen pollution amount Q is calculated by the agricultural fertilization nitrogen pollution calculation formula. 农田 :

[0091] Q 农田 =∑(fertilizer amount (kg / mu)*loss coefficient (%)),

[0092] The amount of fertilizer applied is the amount of fertilizer applied to the farmland area in the target watershed, and the loss coefficient is the loss coefficient of the fertilizer applied to the farmland area in the target watershed.

[0093] In this embodiment, based on the inventive concept of this application, those skilled in the art can combine the commonly used technical means in this field and the existing technology to obtain the amount of fertilizer applied to the farmland area in the target watershed and the loss coefficient of the fertilizer applied to the farmland area in the target watershed.

[0094] In one embodiment, when the nitrogen pollution associated characteristic data is industrial pollution data (wastewater discharge in industrial areas), the corresponding nitrogen pollution amount Q is calculated using the industrial wastewater nitrogen pollution calculation formula. 工业 :

[0095]

[0096] The wastewater discharge volume is the wastewater discharge volume of the industrial area in the target watershed, and the total nitrogen concentration of the wastewater is the nitrogen concentration of the wastewater discharged from the industrial area in the target watershed.

[0097] In this embodiment, based on the inventive concept of this application, those skilled in the art can combine the commonly used technical means in this field and the existing technology to obtain the wastewater discharge volume of the industrial area in the target watershed and the nitrogen concentration of the wastewater discharged from the industrial area in the target watershed.

[0098] In this embodiment, when the nitrogen pollution associated characteristic data is livestock breeding data (total amount of livestock excretion), the corresponding nitrogen pollution amount Q is calculated using the livestock manure nitrogen pollution calculation formula. 牲畜 :

[0099] Q 牲畜 =∑(breeding quantity*excretion coefficient*nitrogen content (%)*loss rate (%)),

[0100] Among them, the breeding number is the breeding number of livestock in the target watershed, the excretion coefficient is the coefficient of livestock manure discharged into the sea-flowing river channel in the target watershed, the nitrogen content is the nitrogen content of livestock manure in the target watershed, and the loss rate is the loss rate of livestock manure discharged into the sea-flowing river channel in the target watershed.

[0101] In this embodiment, based on the inventive concept of this application, those skilled in the art can combine the commonly used technical means in this field and the existing technology to obtain the number of livestock raised in the target watershed, the coefficient of livestock manure discharged into the sea channel of the target watershed, the nitrogen content of livestock manure in the target watershed, and the loss rate of livestock manure discharged into the sea channel of the target watershed.

[0102] In this embodiment, when the nitrogen pollution associated characteristic data is human life data (total amount of human sewage discharge), the corresponding nitrogen pollution amount Q is calculated using the human life nitrogen pollution calculation formula. 人类生活 :

[0103] Q 人类生活 =∑(urban population*per capita sewage volume*total nitrogen concentration*365*(1-sewage treatment rate)),

[0104] Among them, the urban population is the number of people living in the urban area of ​​the target basin, the per capita sewage volume is the average daily sewage discharge of the people living in the urban area of ​​the target basin, the total nitrogen concentration is the nitrogen concentration of the sewage discharged by the people living in the urban area of ​​the target basin, and the sewage treatment rate is the nitrogen pollution reduction rate of the sewage discharged by the people living in the urban area of ​​the target basin.

[0105] In this embodiment, based on the inventive concept of this application, those skilled in the art can combine the commonly used technical means in this field and the existing technology to obtain the number of living population in the urban area in the target watershed, the average sewage discharge volume of the living population in the urban area in the target watershed, the nitrogen concentration of the discharged sewage of the living population in the urban area in the target watershed, and the nitrogen pollution reduction rate of the discharged sewage of the living population in the urban area in the target watershed.

[0106] S406. Calculate the nitrogen pollution contribution value (Value) corresponding to the nitrogen pollution correlation characteristic data based on the nitrogen pollution amount corresponding to the nitrogen pollution correlation characteristic data, the nitrogen pollution amount at the estuary of the river flowing into the sea in the target river basin, and the nitrogen pollution contribution value calculation formula:

[0107]

[0108] Among them, Q pollution (i) is the nitrogen pollution amount corresponding to the i-th nitrogen pollution-related characteristic data, Q pollution It is the amount of nitrogen pollution at the estuary of the rivers flowing into the sea in the target basin.

[0109] In addition, the present application also provides some steps for monitoring nitrogen pollution at river estuaries, which can be applied to the coupled model-based method for monitoring nitrogen pollution at river estuaries to perform a significance test on the Pearson correlation coefficient between the acquired remote sensing image feature data and the nitrogen pollution level at the estuary of the river estuary in the target basin. The steps include:

[0110] S403a. Calculate the significance parameter corresponding to the Pearson correlation coefficient according to the significance verification formula:

[0111]

[0112] Wherein, t is the significance parameter corresponding to the Pearson correlation coefficient.

[0113] S403b: If the significance parameter corresponding to the Pearson correlation coefficient is greater than a preset value, it is determined that the remote sensing image feature data has a significant correlation with the amount of nitrogen pollution at the estuary of the river flowing into the sea in the target watershed.

[0114] In one embodiment, the preset value can refer to a t-distribution critical value table, where n-2 is the degree of freedom.

[0115] In step S50, nitrogen pollution monitoring is performed on the target watershed according to the nitrogen pollution contribution values ​​corresponding to the respective nitrogen pollution associated characteristic data and in combination with the preset sea estuary water quality monitoring criteria.

[0116] In one embodiment, technicians can adopt the following practices to monitor nitrogen pollution in the target basin: first, hierarchical monitoring, listing nitrogen pollution-related characteristic data with nitrogen pollution contribution values ​​higher than a preset threshold as key monitoring objects, deploying online sensors to monitor the corresponding nitrogen pollution-related characteristic data of the target basin in real time, and using regular detection for nitrogen pollution-related characteristic data of the target basin with low nitrogen pollution contribution values; second, path tracking, adding mobile monitoring buoys to the emission diffusion path (such as river junctions and ocean current mainstream lines) between the estuary and the nitrogen pollution-related characteristic data of the target basin with high contribution values; third, dynamic response When the contribution value of a certain nitrogen pollution-related characteristic data rises sharply in a short period of time, it will automatically trigger the coordinated verification of drone patrol and satellite remote sensing to quickly locate the emission source corresponding to the nitrogen pollution-related characteristic data for remediation; fourth, the governance linkage will link the nitrogen pollution contribution value ranking with the pollution discharge permit review and environmental protection law enforcement priority. For example, the emission sources corresponding to the nitrogen pollution-related characteristic data with the top 10% nitrogen pollution contribution values ​​for three consecutive months will be forced to install smart sewage gates to realize closed-loop management of nitrogen pollution control; in addition, the historical contribution data can be combined to optimize the layout of monitoring points, eliminate redundant monitoring equipment with long-term low contribution values, and reduce operation and maintenance costs.

[0117] Example 2

[0118] Please refer to Figure 5 This application also provides a coupled model-based nitrogen pollution monitoring system for estuaries, to implement the steps of the coupled model-based nitrogen pollution monitoring method for estuaries described in the above embodiment. The coupled model-based nitrogen pollution monitoring system for estuaries includes: a surface water nitrogen pollution acquisition unit 101, a groundwater nitrogen pollution acquisition unit 102, an estuary nitrogen pollution acquisition unit 103, a nitrogen pollution contribution acquisition unit 104, and a nitrogen pollution monitoring unit 105.

[0119] The surface water nitrogen pollution amount acquisition unit 101 is used to acquire the nitrogen pollution amount of the surface water of the target basin, wherein the target basin includes a plurality of rivers flowing into the sea, and the surface water nitrogen pollution amount is the total nitrogen load of the surface water in the target basin input into the rivers flowing into the sea;

[0120] The groundwater nitrogen pollution amount acquisition unit 102 is used to acquire the groundwater nitrogen pollution amount in the target basin, wherein the groundwater nitrogen pollution amount is the total nitrogen load of the groundwater in the target basin input to the river into the sea;

[0121] The estuary nitrogen pollution amount acquisition unit 103 is used to add the surface water body nitrogen pollution amount and the groundwater body nitrogen pollution amount to obtain the estuary nitrogen pollution amount of the river flowing into the sea in the target basin;

[0122] The nitrogen pollution contribution value acquisition unit 104 is used to obtain nitrogen pollution correlation characteristic data of the target watershed, and calculate the nitrogen pollution contribution value corresponding to the nitrogen pollution correlation characteristic data according to the nitrogen pollution amount at the estuary of the river flowing into the sea in the target watershed;

[0123] The nitrogen pollution monitoring unit 105 is configured to monitor nitrogen pollution in the target watershed according to the nitrogen pollution contribution values ​​corresponding to the nitrogen pollution associated characteristic data and in combination with preset sea estuary water quality monitoring criteria.

[0124] It should be noted that the above embodiment provides a method for monitoring nitrogen pollution at an estuary of an estuary based on a coupling model, and only uses the division of the above-mentioned functional modules as an example when implementing a method for monitoring nitrogen pollution at an estuary of an estuary based on a coupling model. In actual applications, the above-mentioned functions can be assigned to different functional modules as needed, that is, the internal structure of the equipment can be divided into different functional modules to complete all or part of the functions described above.

[0125] In addition, the above embodiment provides a nitrogen pollution monitoring system for river estuaries based on a coupling model and a nitrogen pollution monitoring method for river estuaries based on a coupling model in Example 1. The implementation process is detailed in the method embodiment, i.e., Example 1, and will not be repeated here.

[0126] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art may make various modifications and improvements without departing from the spirit of the present application, and the present application is intended to encompass such modifications and variations.

Claims

1. A method for monitoring nitrogen pollution in estuaries based on a coupled model, comprising the following steps: Obtaining nitrogen pollution in surface water of a target watershed, wherein the target watershed includes a plurality of rivers flowing into the sea, and the nitrogen pollution in surface water is the total nitrogen load input from surface water in the target watershed to the rivers flowing into the sea; Obtaining nitrogen pollution in groundwater of the target watershed, wherein the nitrogen pollution in groundwater is the total nitrogen load of groundwater in the target watershed input into the river flowing into the sea; Adding the nitrogen pollution amount of the surface water body to the nitrogen pollution amount of the groundwater body to obtain the nitrogen pollution amount of the estuary of the river flowing into the sea in the target basin; Obtaining nitrogen pollution correlation characteristic data of the target watershed, and calculating a nitrogen pollution contribution value corresponding to the nitrogen pollution correlation characteristic data based on the nitrogen pollution amount at the estuary of the river flowing into the sea in the target watershed; According to the nitrogen pollution contribution values ​​corresponding to the respective nitrogen pollution associated characteristic data, combined with the preset sea estuary water quality monitoring criteria, nitrogen pollution monitoring is performed on the target watershed.

2. According to the method for monitoring nitrogen pollution in estuaries of claim 1, the step of obtaining the nitrogen pollution level of surface water in the target basin comprises: According to the organic nitrogen pollution load calculation formula, the organic nitrogen load ORGN of the surface water in the target basin input into the river entering the sea is calculated: Among them, ρ orgN is the organic nitrogen concentration at 10 mm above the soil surface in the target watershed, m is the soil loss in the target watershed, A is the area of ​​the target watershed, ε N is the nitrogen enrichment factor of the target watershed; According to the nitrate nitrogen pollution load calculation formula, the nitrate nitrogen load NSURQ input from the surface water in the target basin to the river flowing into the sea is calculated: Among them, ρ NO3ly is the content of nitrate nitrogen in the soil in the target basin, W surf is the amount of surface water retained in the soil layer in the target basin, θ e is the porosity of the target basin, SAT ly is the content of saturated water in the soil in the target watershed; Construct a watershed hydrological model to obtain the nitrogen pollution TN of the surface water in the target watershed: TN=ORGN+NSURQ, Among them, TN is the nitrogen pollution amount of the surface water in the target basin, ORGN is the organic nitrogen load of the surface water in the target basin input into the river estuary, and NSURQ is the nitrate nitrogen load of the surface water in the target basin input into the river estuary.

3. The method for monitoring nitrogen pollution in an estuary according to claim 1, wherein the step of obtaining the nitrogen pollution level of the groundwater in the target basin comprises: Obtaining a groundwater sample from the target watershed and performing nitrogen digestion to obtain a digestion solution; According to the digestion solution and the calculation formula of total nitrogen concentration in groundwater, the total nitrogen concentration C of the groundwater in the target basin is calculated. TN ; Among them, C TN is the total nitrogen concentration of groundwater in the target basin, A 220 A is the absorbance of the digestion solution measured at a light wavelength of 220 nm. 275 is the absorbance of the digestion solution measured at a light wavelength of 275 nm, D is the dilution multiple of the digestion solution, V is the volume of the digestion solution, and V sample is the volume of the groundwater sample in the target basin, ε is the slope of the preset calibration curve, and L is the optical path length of the cuvette; The nitrogen pollution amount of the groundwater in the target watershed is obtained according to the total nitrogen concentration of the groundwater in the target watershed.

4. The method for monitoring nitrogen pollution in an estuary according to claim 3, wherein the steps of obtaining a groundwater sample from the target basin and performing nitrogen digestion to obtain a digestion solution comprise: By setting monitoring wells at preset intervals in the target watershed, a plurality of groundwater samples of the target watershed are obtained from the flow path of the groundwater in the target watershed, and the samples are mixed to obtain a groundwater sample of the target watershed; An alkaline potassium persulfate solution is added to the groundwater sample of the target watershed, and digested at 120 degrees Celsius for 30 minutes to oxidize the organic nitrogen and nitrite nitrogen in the groundwater sample of the target watershed into nitrate nitrogen, thereby obtaining a digestion solution.

5. The method for monitoring nitrogen pollution in an estuary according to claim 3, wherein the step of obtaining the nitrogen pollution level of the groundwater in the target basin according to the total nitrogen concentration of the groundwater in the target basin comprises: According to the total nitrogen concentration of groundwater in the target basin and the calculation formula of groundwater nitrogen pollution, the first groundwater nitrogen pollution amount UTN of the target basin is calculated: UTN=C TN ·Q groundwater , Among them, UTN is the nitrogen pollution amount of the first groundwater body in the target basin, Q groundwater is the groundwater flow rate in the target basin; Construct a groundwater recharge model to obtain the surface water recharge Q of the target basin recharge : Among them, Q recharge is the surface water recharge to groundwater in the target basin, R i is the rainfall of the i-th sub-basin in the target basin, ET i is the evapotranspiration of the i-th sub-basin in the target basin, Q surf,i is the surface runoff of the ith sub-basin in the target basin, and n is the number of sub-basins in the target basin; Create a nitrogen migration coupling equation to obtain the nitrogen pollution UTN in the groundwater of the target basin total : UTN total =UTN+Q recharge -S decay , Among them, UTN total is the nitrogen pollution level of groundwater in the target basin, S decay is the nitrogen degradation amount of microorganisms in the target watershed.

6. The method for monitoring nitrogen pollution in an estuary according to claim 1, wherein the step of obtaining nitrogen pollution correlation characteristic data of the target watershed comprises: Acquiring several remote sensing image feature data of the target watershed; Time-align each of the remote sensing image feature data with the nitrogen pollution level at the estuary of the river flowing into the sea in the target basin, and perform standardization: Wherein, X is the remote sensing image feature data, Y is the nitrogen pollution amount at the estuary of the river flowing into the sea in the target basin at the same time point corresponding to the remote sensing image feature data after time alignment, and X norm is the standardized data corresponding to the remote sensing image feature data, Y norm is the standardized data corresponding to the nitrogen pollution in the estuary, μX is the mean value of the remote sensing image feature data in the preset time period, μY is the mean value of the nitrogen pollution in the estuary in the preset time period, σX is the standard deviation of the remote sensing image feature data in the preset time period, and σY is the standard deviation of the nitrogen pollution in the estuary in the preset time period; Calculate the Pearson correlation coefficient r between each of the remote sensing image feature data and the nitrogen pollution level at the estuary of the river flowing into the sea in the target basin: Wherein, n is the number of standardized data corresponding to the remote sensing image feature data and the number of standardized data corresponding to the nitrogen pollution amount at the estuary of the river entering the sea in the target basin, is the mean of the standardized data corresponding to the remote sensing image feature data, is the mean of the standardized data corresponding to the nitrogen pollution in the estuary, X i is the i-th standardized data corresponding to the remote sensing image feature data, Y i is the i-th standardized data corresponding to the nitrogen pollution in the estuary; If the Pearson correlation coefficient between the remote sensing image feature data and the nitrogen pollution amount at the estuary of the river flowing into the sea in the target river basin is greater than a preset threshold, it is determined that the remote sensing image feature data is strongly correlated with the nitrogen pollution amount at the estuary of the river flowing into the sea in the target river basin, and the corresponding remote sensing image feature data is the nitrogen pollution association feature data of the target river basin.

7. The method for monitoring nitrogen pollution at an estuary of a river entering the sea according to claim 6, wherein if the Pearson correlation coefficient between the remote sensing image feature data and the nitrogen pollution level at the estuary of the river entering the sea in the target river basin is greater than a preset threshold, then the step of determining that the remote sensing image feature data is strongly correlated with the nitrogen pollution level at the estuary of the river entering the sea in the target river basin comprises: If the absolute value of the Pearson correlation coefficient between the remote sensing image feature data and the nitrogen pollution amount at the estuary of the river flowing into the sea in the target river basin is greater than 0.5, it is determined that the remote sensing image feature data is strongly correlated with the nitrogen pollution amount at the estuary of the river flowing into the sea in the target river basin.

8. The method for monitoring nitrogen pollution in an estuary according to claim 6, characterized in that: The method for monitoring nitrogen pollution at the estuary of a river entering the sea further includes a step for performing a significance test on the Pearson correlation coefficient between the acquired remote sensing image feature data and the nitrogen pollution amount at the estuary of the river entering the sea in the target basin: According to the significance verification formula, the significance parameter corresponding to the Pearson correlation coefficient is calculated: Wherein, t is the significance parameter corresponding to the Pearson correlation coefficient; If the significance parameter corresponding to the Pearson correlation coefficient is greater than a preset value, it is determined that the remote sensing image feature data has a significant correlation with the amount of nitrogen pollution at the estuary of the river flowing into the sea in the target basin.

9. The method for monitoring nitrogen pollution at an estuary according to any one of claims 6 to 8, wherein the step of calculating the nitrogen pollution contribution value corresponding to the nitrogen pollution correlation characteristic data based on the nitrogen pollution amount at the estuary of the river entering the sea in the target basin comprises: Calculating the nitrogen pollution amount corresponding to the nitrogen pollution correlation characteristic data according to the nitrogen pollution correlation characteristic data; According to the nitrogen pollution amount corresponding to the nitrogen pollution correlation characteristic data, the nitrogen pollution amount at the estuary of the river flowing into the sea in the target basin, and the nitrogen pollution contribution value calculation formula, the nitrogen pollution contribution value corresponding to the nitrogen pollution correlation characteristic data is calculated: Among them, Q pollution (i) is the nitrogen pollution amount corresponding to the i-th nitrogen pollution-related characteristic data, Q pollution It is the amount of nitrogen pollution at the estuary of the rivers flowing into the sea in the target basin.

10. A nitrogen pollution monitoring system for estuaries based on a coupling model, characterized in that: The nitrogen pollution monitoring system for estuaries includes: a surface water nitrogen pollution amount acquisition unit, configured to acquire the nitrogen pollution amount of the surface water of a target basin, wherein the target basin includes a plurality of rivers flowing into the sea, and the surface water nitrogen pollution amount is the total nitrogen load of the surface water in the target basin input into the rivers flowing into the sea; a groundwater nitrogen pollution amount acquisition unit, configured to acquire the groundwater nitrogen pollution amount in the target basin, wherein the groundwater nitrogen pollution amount is the total nitrogen load of the groundwater in the target basin input to the river estuary; an estuary nitrogen pollution amount acquisition unit, configured to add the nitrogen pollution amount of the surface water body to the nitrogen pollution amount of the groundwater body to obtain the nitrogen pollution amount of the estuary of the river flowing into the sea in the target basin; a nitrogen pollution contribution value acquisition unit, configured to acquire nitrogen pollution correlation characteristic data of the target watershed, and calculate a nitrogen pollution contribution value corresponding to the nitrogen pollution correlation characteristic data based on the nitrogen pollution amount at the estuary of the river flowing into the sea in the target watershed; The nitrogen pollution monitoring unit is used to monitor nitrogen pollution in the target watershed according to the nitrogen pollution contribution value corresponding to each of the nitrogen pollution-related characteristic data and in combination with the preset sea estuary water quality monitoring criteria.

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