Soil respiration CO2 flux and δ 13 Method and apparatus for determining C flux

Abstract

The present application relates to a kind of soil respiration CO2 flux and δ 13 The present application relates to a kind of soil respiration CO2 flux and δ 12 The present application relates to a kind of soil respiration CO2 flux and δ 13 The present application relates to a kind of soil respiration CO2 flux and δ 13 The present application relates to a kind of soil respiration CO2 flux and δ 13 The present application relates to a kind of soil respiration CO2 flux and δ

Description

Technical Field

[0001] This invention relates to the field of soil testing technology, and more particularly to a method for measuring soil respiration CO2 flux and δ. 13 Method and apparatus for determining C flux. Background Technology

[0002] Soil respiration refers to the process by which soil produces and releases carbon dioxide, primarily including the decomposition of organic matter by soil microorganisms (heterotrophic respiration) and root respiration by plants (autotrophic respiration). It is a crucial link in the carbon cycle of terrestrial ecosystems, and its flux directly affects atmospheric CO2 concentration, having a significant feedback effect on global climate change. Therefore, accurately measuring soil respiration CO2 flux has always been a research hotspot in ecology, environmental science, and agronomy. Currently, due to limitations in measurement methods, soil respiration CO2 flux measurements suffer from inaccurate data collection, resulting in inaccurate measurement results. Summary of the Invention

[0003] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a method for measuring soil respiration CO2 flux and δ 13 The method and apparatus for determining CO2 flux solve the technical problem of inaccurate data collection in soil respiration CO2 flux measurement.

[0004] To achieve the above objectives, the main technical solutions adopted by the present invention include:

[0005] The first aspect of the present invention provides soil respiration CO2 flux and δ 13 C. Flux determination method.

[0006] The soil respiration CO2 flux and δ proposed in the embodiments of the present invention 13 Methods for determining C-flux include:

[0007] The measurement deviation of the gas concentration detection device is obtained by correcting the measurement deviation of the gas concentration detection device using a standard gas.

[0008] The soil respiration CO2 amount is collected by the gas concentration detection device, and the collected soil respiration CO2 amount data is filtered based on the gas chamber exhaust characteristics of the gas concentration detection device to obtain the effective collected data of soil respiration CO2 amount in the gas chamber.

[0009] For outliers in the effective collected data of soil respiration CO2 in the gas chamber, a linear fitting or neural network model is used for quality control to remove the outliers.

[0010] Based on the measurement deviation of the gas concentration detection device, the effective collected data of soil respiration CO2 in the gas chamber after removing the outliers are corrected for measurement deviation to obtain the corrected soil respiration CO2 concentration value.

[0011] Based on the corrected soil respiration CO2 concentration value, the soil respiration CO2 flux is determined, and based on the soil respiration CO2 flux... 12 CO2 flux and 13 CO2 flux, determine δ 13 C-flux.

[0012] In some instances, the data on the collected soil respiration CO2 volume based on the exhaust characteristics of the gas chamber of the gas concentration detection device is filtered to obtain effective collected data on the soil respiration CO2 volume within the gas chamber, including:

[0013] Based on the exhaust characteristics of the gas chamber of the gas concentration detection device, the curvature change nodes of the data curve when the gas concentration detection device measures the CO2 concentration of soil respiration are determined.

[0014] Based on the curvature change nodes of the data curve when measuring soil respiration CO2 concentration using the gas concentration detection device, the target curvature node of the data curve after the gas chamber is filled with soil respiration CO2 is obtained.

[0015] The soil respiration CO2 concentration measurement data after determining the target curvature node is the effective collection data of soil respiration CO2 in the gas chamber.

[0016] In some instances, the curvature change nodes of the data curve during soil respiration CO2 concentration measurement based on the gas concentration detection device, to obtain the target curvature node of the data curve after the gas chamber is filled with soil respiration CO2, include:

[0017] Based on the curvature change nodes of the data curve when measuring CO2 concentration in soil respiration using the gas concentration detection device, the curvature change nodes are obtained where the curvature changes from negative to zero and from zero to positive.

[0018] The curvature change nodes that change from negative to zero and from zero to positive are determined as the target curvature nodes of the data curve after the air chamber is filled with soil respiration CO2.

[0019] In some instances, the measurement deviation correction of the effective collected data of soil respiration CO2 in the gas chamber based on the measurement deviation of the gas concentration detection device, to obtain the corrected soil respiration CO2 concentration value, includes:

[0020] Based on the measurement deviation of the gas concentration detection device, please determine the concentration correction model;

[0021] Based on the concentration correction model, the effective collected data of soil respiration CO2 in the gas chamber are corrected for measurement bias to obtain the corrected soil respiration CO2 concentration value; wherein, the concentration correction model includes:

[0022] ; where X L s,T For the corrected soil respiration CO2 light isotope concentration value, X L 1,T The true molar concentration of light isotope standard gas 1, X L 2,T The true molar concentration of light isotope standard gas 2, X L s,M The measured values ​​of light isotope concentration of CO2 in soil respiration before correction, X L 1,M The measured molar concentration of light isotope standard gas 1, X L 2,M The molar concentration of light isotope standard gas 2 is measured.

[0023] ; where X H s,T X represents the corrected soil respiration CO2 heavy isotope concentration value; H 1,T X represents the true molar concentration of heavy isotope standard gas 1; H 2,T X represents the true molar concentration of heavy isotope standard gas 2; H s,M The soil respiration CO2 heavy isotope concentration measurement before correction; X H 1,M X represents the measured molar concentration of heavy isotope standard gas 1; H 2,M The molar concentration of heavy isotope standard gas 2 is measured.

[0024] In some instances, determining the soil respiration CO2 flux based on the corrected soil respiration CO2 concentration value includes:

[0025] Based on the corrected soil respiration CO2 concentration value and the concentration flux model, the soil respiration CO2 flux is determined; wherein, the concentration flux model includes:

[0026] ;in,

[0027] Fc is the soil respiration CO2 flux; V is the total volume of the system; P0 is the initial gas pressure in the gas chamber; W0 is the initial water vapor concentration in the gas chamber; R is Planck's constant; S is the soil measurement area; T0 is the initial air temperature in the gas chamber. This is the corrected soil respiration CO2 concentration value.

[0028] In some instances, the CO2 flux based on soil respiration... 12 CO2 flux and 13 CO2 flux, determine δ 13 C flux includes:

[0029] Based on the soil respiration CO2 flux 12 CO2 flux and 13 CO2 flux and δ 13 C-flux model, determining δ 13 C flux; where δ 13 The C-flux model includes:

[0030] ;in, Breathing in the soil 13 CO2 isotope flux; Breathing for the soil 12 CO2 isotope flux, R VPDB It is a constant.

[0031] In some instances, before correcting the measurement deviation of the effective collected data on soil respiration CO2 concentration in the gas chamber based on the measurement deviation of the gas concentration detection device to obtain the corrected soil respiration CO2 concentration value, the method includes:

[0032] The effective data of CO2 respiration in the soil within the gas chamber were linearly fitted to obtain the difference between the measured value and the fitted value.

[0033] Based on the difference between the measured value and the fitted value, determine the average value and standard deviation of the difference;

[0034] Data with a standard deviation exceeding a predetermined value are removed from the valid data collection of CO2 respiration in the air chamber.

[0035] A second aspect of the present invention provides soil respiration CO2 flux and δ 13 C-flux determination device, comprising:

[0036] The device deviation correction module is used to correct the measurement deviation of the gas concentration detection device using a standard gas, and to obtain the measurement deviation of the gas concentration detection device.

[0037] The data acquisition module is used to acquire data on soil respiration CO2 through the gas concentration detection device, and to filter the acquired soil respiration CO2 data based on the gas chamber exhaust characteristics of the gas concentration detection device to obtain effective acquired data on soil respiration CO2 in the gas chamber.

[0038] The data processing module is used to perform quality control on outliers in the effective data collection of soil respiration CO2 in the gas chamber using linear fitting or neural network models, and to remove the outliers.

[0039] The data deviation correction module is used to correct the measurement deviation of the effective collected data of soil respiration CO2 in the gas chamber after removing the outliers, based on the measurement deviation of the gas concentration detection device, so as to obtain the corrected soil respiration CO2 concentration value.

[0040] The flux determination module is used to determine the soil respiration CO2 flux based on the corrected soil respiration CO2 concentration value, and based on the soil respiration CO2 flux... 12 CO2 flux and 13 CO2 flux, determine δ 13 C-flux.

[0041] A third aspect of the present invention provides a computer-readable storage medium storing soil respiration CO2 flux and δ 13 C-flux determination procedure, soil respiration CO2 flux and δ 13 When the C-flux determination program is executed by the processor, it realizes the soil respiration CO2 flux and δ-flux described in the first aspect above. 13 C. Flux determination method.

[0042] A fourth aspect of this invention provides an electronic device, including a memory, a processor, and soil respiration CO2 flux and δ stored in the memory and operable on the processor. 13 The C-flux determination procedure is executed by the processor to determine the soil respiration CO2 flux and δ. 13 When determining the C-flux, the soil respiration CO2 flux and δ-flux mentioned in the first aspect above are implemented. 13 C. Flux determination method.

[0043] A soil respiration CO2 flux and δ of the present invention 13The method for determining C-flux includes: correcting the measurement deviation of a gas concentration detection device using a standard gas to obtain the measurement deviation of the gas concentration detection device; collecting soil respiration CO2 data using the gas concentration detection device, and filtering the collected soil respiration CO2 data based on the exhaust characteristics of the gas chamber of the gas concentration detection device to obtain valid collected data of soil respiration CO2 within the gas chamber; correcting the measurement deviation of the valid collected data of soil respiration CO2 within the gas chamber based on the measurement deviation of the gas concentration detection device to obtain a corrected soil respiration CO2 concentration value; determining the soil respiration CO2 flux based on the corrected soil respiration CO2 concentration value, and determining the soil respiration CO2 flux based on the soil respiration CO2 flux. 12 CO2 flux and 13 CO2 flux, determine δ 13 C-flux. In this application, by correcting the measurement deviation of the gas concentration detection device and filtering the collected soil respiration CO2 data based on the gas chamber exhaust characteristics of the gas concentration detection device, effective collected data of soil respiration CO2 in the gas chamber are obtained. Based on the corrected soil respiration CO2 concentration value, the soil respiration CO2 flux is determined, and based on the soil respiration CO2 flux... 12 CO2 flux and 13 CO2 flux, determine δ 13 C flux is beneficial for removing data with large errors from the collected data and for bias correction, thereby improving soil respiration CO2 flux and δ¹⁴C flux. 13 C. Flux measurement accuracy. Attached Figure Description

[0044] Figure 1 A soil respiration CO2 flux and δ provided in this embodiment of the invention 13 Flowchart of C-flux determination method;

[0045] Figure 2a The high-concentration standard gas ( ) provided for the observation period in the embodiments of the present invention 12 CO2 concentration, 13 CO2 concentration and δ 13 C) Time series (raw data) and switching time point illustration Figure 1 ;

[0046] Figure 2b The concentration standard gas provided during the observation period for the embodiments of the present invention ( 12 CO2 concentration, 13 CO2 concentration and δ 13 C) Time series (raw data) and diagram of switching time points (II);

[0047] Figure 2c The low-concentration standard gas provided during the observation period for the embodiments of the present invention ( 12 CO2 concentration, 13 CO2 concentration and δ 13 C) Time series (raw data) and switching time point illustration Figure 3 ;

[0048] Figure 3 This is a time series diagram of effective observation data of one circulating standard gas provided in an embodiment of the present invention;

[0049] Figure 4 δ provided for embodiments of the present invention 13 C. Time series plots of raw data, calibrated data, and stable isotope mass spectrometry (IRMS) data;

[0050] Figure 5 The following are time series plots of raw CO2 concentration data, calibrated data, and stable isotope mass spectrometry (IRMS) data provided in the embodiments of the present invention.

[0051] Figure 6 This is a schematic diagram of the soil respiration CO2 concentration testing process provided in an embodiment of the present invention;

[0052] Figure 7a Sample gas during observation provided for embodiments of the present invention ( 12 CO2 concentration, 13 CO2 concentration switching time point illustration Figure 1 ;

[0053] Figure 7b Sample gas during observation provided for embodiments of the present invention ( 12 CO2 concentration, 13 Schematic diagram of CO2 concentration switching time points (II);

[0054] Figure 7c Sample gas during observation provided for embodiments of the present invention ( 12 CO2 concentration, 13 CO2 concentration switching time point illustration Figure 3 ;

[0055] Figure 7d Sample gas during observation provided for embodiments of the present invention ( 12 CO2 concentration, 13 CO2 concentration switching time point illustration Figure 4 ;

[0056] Figure 816 sets of soil respiration data provided in the embodiments of the present invention 12 CO2 concentration, 13 CO2 concentration and δ 13 Time series plot of the raw C-value and the three-point calibrated C-value;

[0057] Figure 9 A soil respiration CO2 flux and δ provided in this embodiment of the invention 13 Schematic diagram of the C-flux determination device. Detailed Implementation

[0058] To better explain and facilitate understanding of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0059] The soil respiration CO2 flux and δ proposed in the embodiments of the present invention 13 A method for determining soil respiration CO2 flux is used to address the problem of inaccurate data collection in soil respiration CO2 flux measurement. This method corrects for measurement deviations in the gas concentration detection device and filters the collected soil respiration CO2 data based on the exhaust characteristics of the gas chamber of the detection device. This yields valid collected data on soil respiration CO2 within the gas chamber. Based on the corrected soil respiration CO2 concentration value, the soil respiration CO2 flux is determined, and the flux is further analyzed based on the concentration of CO2 within the soil respiration CO2. 12 CO2 flux and 13 CO2 flux, determine δ 13 C flux is beneficial for removing data with large errors from the collected data and for bias correction, thereby improving soil respiration CO2 flux and δ¹⁴C flux. 13 C. Flux measurement accuracy.

[0060] To better understand the above technical solutions, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the present invention can be understood more clearly and thoroughly, and that the scope of the present invention can be fully conveyed to those skilled in the art.

[0061] Figure 1 A soil respiration CO2 flux and δ provided in this embodiment of the invention 13 C. Flux Determination Method Flowchart. (See attached flowchart.) Figure 1 As shown, the soil respiration CO2 flux and δ proposed in this embodiment of the invention... 13 Methods for determining C-flux include:

[0062] Step 100: Correct the measurement deviation of the gas concentration detection device using a standard gas to obtain the measurement deviation of the gas concentration detection device;

[0063] Step 110: Collect data on soil respiration CO2 using the gas concentration detection device, and filter the collected soil respiration CO2 data based on the gas chamber exhaust characteristics of the gas concentration detection device to obtain effective collected data on soil respiration CO2 in the gas chamber.

[0064] Step 120: For outliers in the effective data of soil respiration CO2 in the gas chamber, use linear fitting or neural network model for quality control and remove the outliers.

[0065] Step 130: Based on the measurement deviation of the gas concentration detection device, perform measurement deviation correction on the effective collected data of soil respiration CO2 in the gas chamber after removing the outliers, to obtain the corrected soil respiration CO2 concentration value.

[0066] Step 140: Based on the corrected soil respiration CO2 concentration value, determine the soil respiration CO2 flux, and based on the soil respiration CO2 flux... 12 CO2 flux and 13 CO2 flux, determine δ 13 C-flux.

[0067] In this exemplary embodiment, the gas concentration detection device contains a gas chamber. During soil respiration CO2 concentration detection, there is a gas discharge process, which causes a change in the soil respiration CO2 concentration. Before it stabilizes, the soil respiration CO2 concentration in the gas chamber will be inaccurate. Therefore, the effective data collected by detecting the amount of soil respiration CO2 in the gas chamber will be relatively more accurate.

[0068] In this exemplary embodiment, standard gas 12 CO2 concentration and 13 CO2 concentration calculation. Standard gas. 12 The true value of the total CO2 concentration was provided by the standard gas company, δ 13 The C value was determined using a stable isotope mass spectrometer. (The C value in the standard gas...) 12 CO2 concentration and 13 CO2 concentration values ​​can be obtained from known total [CO2] and δ 13 The value of C is obtained using the following formula:

[0069] ;in,

[0070] Where [CO2] is the total CO2 mixture ratio including all isotopes; f is the mixture ratio including all isotopes except [CO2]. 12 CO2] and [ 13The proportion of other isotopes besides CO2 (0.00474); Ra is the molar ratio of light and heavy isotopes in the sample; R VPDB It is standard 13 C / 12 C molar ratio (0.0111797); δa is the carbon isotopic composition.

[0071] in, Figures 2a-2c All of these are standard gases provided during the observation period in the embodiments of the present invention. 12 CO2 concentration, 13 CO2 concentration and δ 13 C) Time series (raw data) and diagram of switching time points. (See diagram below.) Figures 2a-2c As shown, the standard gas measurement time is usually 10-15 minutes. 12 CO2, 13 CO2, δ 13 The switching time for C is calculated separately. Based on the concentration curve during the standard gas measurement period, the data of the first 100 seconds is first removed. Starting from i=101, if the absolute value of the difference between the i-th value and the mean of all subsequent values ​​is less than the std standard deviation of all subsequent values, it is considered that the standard gas switching is normal from the i-th value, and the switching time t1 is calculated. 12 CO2, 13 CO2 and δ 13 The average switching times for C were 231.62±132.88, 144.49±49.15, and 102.26±3.17 s, respectively. Figure 3 This is a time series diagram illustrating effective observation data of a single cyclic standard gas provided in an embodiment of the present invention. Figure 3 As shown in the figure above, 12 C O2 The measured concentrations, from left to right, represent high-concentration standard gas, medium-concentration standard gas, and low-concentration standard gas. (The middle figure represents...) 13 The measured CO2 concentrations, from left to right, represent high-concentration standard gas, medium-concentration standard gas, and low-concentration standard gas. The figure below shows δ... 13 The measured values ​​of C, from left to right, represent high-concentration standard gas, medium-concentration standard gas, and low-concentration standard gas. Figure 4 and Figure 5 δ of the standard gas 13 C. Time series plots of raw data, calibrated data, and stable isotope mass spectrometry (IRMS) data. 12 Time series plots of raw CO concentration data, calibrated CO concentration data, and IRMS data.

[0072] In this application, by correcting the measurement deviation of the gas concentration detection device and filtering the collected soil respiration CO2 data based on the gas chamber exhaust characteristics of the gas concentration detection device, effective collected data of soil respiration CO2 in the gas chamber are obtained. Based on the corrected soil respiration CO2 concentration value, the soil respiration CO2 flux is determined, and based on the soil respiration CO2 flux... 12 CO2 flux and 13 CO2 flux, determine δ 13 C flux is beneficial for removing data with large errors from the collected data and for bias correction, thereby improving soil respiration CO2 flux and δ¹⁴C flux. 13 C. Flux measurement accuracy.

[0073] In some instances, the data on the collected soil respiration CO2 volume based on the exhaust characteristics of the gas chamber of the gas concentration detection device is filtered to obtain effective collected data on the soil respiration CO2 volume within the gas chamber, including:

[0074] Based on the exhaust characteristics of the gas chamber of the gas concentration detection device, the curvature change nodes of the data curve when the gas concentration detection device measures the CO2 concentration of soil respiration are determined.

[0075] Based on the curvature change nodes of the data curve when measuring soil respiration CO2 concentration using the gas concentration detection device, the target curvature node of the data curve after the gas chamber is filled with soil respiration CO2 is obtained.

[0076] The soil respiration CO2 concentration measurement data after determining the target curvature node is the effective collection data of soil respiration CO2 in the gas chamber.

[0077] In this exemplary embodiment, based on the exhaust characteristics of the gas chamber of the gas concentration detection device, when determining the curvature change nodes of the data curve when the gas concentration detection device measures the CO2 concentration of soil respiration, the soil respiration CO2 concentration change curve can be plotted in real time. Figure 6 This is a schematic diagram of the soil respiration CO2 concentration testing process provided in an embodiment of the present invention. Figure 6 As shown, the curves of soil respiration CO2 concentration changes over various time periods are plotted.

[0078] In some instances, the curvature change nodes of the data curve during soil respiration CO2 concentration measurement based on the gas concentration detection device, to obtain the target curvature node of the data curve after the gas chamber is filled with soil respiration CO2, include:

[0079] Based on the curvature change nodes of the data curve when measuring CO2 concentration in soil respiration using the gas concentration detection device, the curvature change nodes are obtained where the curvature changes from negative to zero and from zero to positive.

[0080] The curvature change nodes that change from negative to zero and from zero to positive are determined as the target curvature nodes of the data curve after the air chamber is filled with soil respiration CO2.

[0081] In this exemplary embodiment, as Figure 6 As shown, the curve changes in chamber 1 before and after 100 seconds, with the curvature changing from a negative value to zero and then from zero to a positive value. The soil respiration CO2 concentration data after the curvature reaches zero is considered valid data for soil respiration CO2 collection within the chamber, and is used for soil respiration CO2 measurement. Figures 7a-7d All of these are sample gases provided during the observation period in the embodiments of the present invention. 12 CO2 concentration, 13 CO2 concentration and δ 13 C) Diagram of the switching time point. (See diagram below.) Figures 7a-7d As shown, the red box indicates the switching time.

[0082] In some instances, the measurement deviation correction of the effective collected data of soil respiration CO2 in the gas chamber based on the measurement deviation of the gas concentration detection device, to obtain the corrected soil respiration CO2 concentration value, includes:

[0083] Based on the measurement deviation of the gas concentration detection device, please determine the concentration correction model;

[0084] Based on the concentration correction model, the effective collected data of soil respiration CO2 in the gas chamber are corrected for measurement bias to obtain the corrected soil respiration CO2 concentration value; wherein, the concentration correction model includes:

[0085] ; where X L s,T For the corrected soil respiration CO2 light isotope concentration value, X L 1,T The true molar concentration of light isotope standard gas 1, X L 2,T The true molar concentration of light isotope standard gas 2, X L s,M The measured values ​​of light isotope concentration of CO2 in soil respiration before correction, X L 1,M The measured molar concentration of light isotope standard gas 1, X L 2,M The molar concentration of light isotope standard gas 2 is measured.

[0086] ; where XH s,T X represents the corrected soil respiration CO2 heavy isotope concentration value; H 1,T X represents the true molar concentration of heavy isotope standard gas 1; H 2,T X represents the true molar concentration of heavy isotope standard gas 2; H s,M The soil respiration CO2 heavy isotope concentration measurement before correction; X H 1,M X represents the measured molar concentration of heavy isotope standard gas 1; H 2,M The molar concentration of heavy isotope standard gas 2 is measured.

[0087] In this exemplary embodiment, the concentration correction model enables the correction of soil respiration CO2 concentration values. Lightweight quality control algorithms (such as dynamic switching time judgment) are run on the edge computing module of the observation device to achieve real-time preliminary quality control of the data. Simultaneously, the data is uploaded to the cloud for more complex three-point correction, uncertainty quantification, and machine learning model training, and the optimized model parameters are then distributed to the edge device. Figure 8 16 sets of soil respiration data provided in the embodiments of the present invention 12 CO2, 13 CO2 concentration and δ 13 A time series plot of the raw C-values ​​and the three-point calibrated C-values. (See figure) Figure 8 As shown, this plot illustrates the contrast distribution between the raw data and the three-point correction values.

[0088] In some instances, determining the soil respiration CO2 flux based on the corrected soil respiration CO2 concentration value includes:

[0089] Based on the corrected soil respiration CO2 concentration value and the concentration flux model, the soil respiration CO2 flux is determined; wherein, the concentration flux model includes:

[0090] ;in,

[0091] Fc is the soil respiration CO2 flux; V is the total volume of the system; P0 is the initial gas pressure in the gas chamber; W0 is the initial water vapor concentration in the gas chamber; R is Planck's constant; S is the soil measurement area; T0 is the initial air temperature in the gas chamber. This is the corrected soil respiration CO2 concentration value.

[0092] In this exemplary embodiment, the CO2 flux based on the soil respiration...12 CO2 flux and 13 CO2 flux, determine δ 13 C flux includes:

[0093] Based on the soil respiration CO2 flux 12 CO2 flux and 13 CO2 flux and δ 13 C-flux model, determining δ 13 C flux; where δ 13 The C-flux model includes:

[0094] ;in, Breathing for the soil 13 CO2 isotope flux; Breathing for the soil 12 CO2 isotope flux, R VPDB It is a constant.

[0095] Soil respiration CO2 flux and δ of the present invention 13 The C flux determination method can determine the soil respiration CO2 concentration and its δ0. 13 The C data underwent effective quality control, all valid observation data were extracted, and three-point correction was applied to the drift, thereby accurately calculating soil respiration CO2 and its δ. 13 C-flux.

[0096] In some instances, before correcting the measurement deviation of the effective collected data on soil respiration CO2 concentration in the gas chamber based on the measurement deviation of the gas concentration detection device to obtain the corrected soil respiration CO2 concentration value, the method includes:

[0097] The effective data of CO2 respiration in the soil within the gas chamber were linearly fitted to obtain the difference between the measured value and the fitted value.

[0098] Based on the difference between the measured value and the fitted value, determine the average value and standard deviation of the difference;

[0099] Data points with a standard deviation exceeding a predetermined value are removed from the valid CO2 collection data of soil respiration within the gas chamber. For example, outliers that may appear in the valid observation data are quality controlled using linear fitting or neural network models to remove them.

[0100] In this exemplary embodiment, the present invention breaks through the traditional method for extracting soil respiration CO2 concentration data. It calculates the difference between the measured and fitted values, as well as the mean and standard deviation of the difference. The standard deviation is used to initially confirm the switching time and extract valid observation data. Further, the mean and standard deviation of the extracted valid data are calculated, and invalid data exceeding a predetermined value are removed to confirm the final valid data for soil respiration flux calculation. Drift correction is performed based on a three-point correction method to confirm the accuracy and precision of the data. Finally, soil respiration CO2 and its δ0.05 are accurately calculated. 13 The actual flux of C.

[0101] This application relates to soil respiration CO2 flux and δ 13 Methods for determining C-flux also include:

[0102] A concentration correction model is constructed by performing multi-point measurement deviation correction on the gas concentration detection device using at least two standard gases of different concentrations.

[0103] The gas concentration detection device continuously collects CO2 concentration from soil respiration, and dynamically determines the effective data starting point based on the curvature change nodes of the concentration curve during the gas chamber exhaust process.

[0104] Based on the concentration correction model, the collected data after the effective data starting point are corrected for measurement deviation to obtain the corrected soil respiration CO2 concentration value.

[0105] Based on the corrected concentration value and combined with real-time correction of environmental parameters, the soil respiration CO2 flux is calculated.

[0106] Based on the CO2 flux 12 CO2 and 13 CO2 flux, δ calculated using the error propagation model 13 C-flux.

[0107] The method of dynamically determining the effective data starting point based on the curvature change nodes of the concentration curve during the gas chamber exhaust process includes:

[0108] The second derivative of the concentration curve is calculated to identify the nodes where the curvature changes from negative to positive and remains stable, thereby obtaining effective observation data.

[0109] For possible outliers in the valid observation data, linear fitting or neural network models are used for quality control to remove outliers.

[0110] The validity of the data is determined by combining the concentration change rate with the time threshold.

[0111] In this exemplary embodiment, the concentration correction model is a nonlinear correction model constructed based on least squares fitting or a neural network.

[0112] The environmental parameters include air temperature, relative humidity, and atmospheric pressure, and are collected in real time through embedded sensors.

[0113] The calculation of the uncertainty of the δ¹³C flux includes:

[0114] Error propagation analysis was performed on concentration measurement error, standard gas error, and fitting error.

[0115] Output the confidence interval or standard error of the flux value.

[0116] In this exemplary embodiment, it also includes:

[0117] Perform preliminary throughput calculations and quality control on edge devices;

[0118] Model training, historical data analysis, and parameter optimization are performed on a cloud platform, and the model is then distributed to edge devices.

[0119] In this exemplary embodiment, simultaneous measurement of multiple air chambers is supported to generate a spatial distribution map of soil respiration flux;

[0120] Combine geographic information systems to conduct spatiotemporal flux variation analysis and visualization.

[0121] This invention provides a method for measuring soil respiration CO2 flux and δ 13 C. Flux determination device. Figure 9 A soil respiration CO2 flux and δ provided in this embodiment of the invention 13 A schematic diagram of the C-flux determination device. (See diagram below.) Figure 9 As shown, soil respiration CO2 flux and δ 13 C-flux determination device, comprising:

[0122] The device deviation correction module 50 is used to correct the measurement deviation of the gas concentration detection device using a standard gas to obtain the measurement deviation of the gas concentration detection device.

[0123] The data acquisition module 51 is used to acquire data on soil respiration CO2 through the gas concentration detection device, and to filter the acquired soil respiration CO2 data based on the gas chamber exhaust characteristics of the gas concentration detection device to obtain effective acquired data on soil respiration CO2 in the gas chamber.

[0124] Data processing module 52 is used to perform quality control on outliers in the effective collection data of soil respiration CO2 in the gas chamber using linear fitting or neural network models, and to remove the outliers.

[0125] The data deviation correction module 53 is used to correct the measurement deviation of the effective collected data of soil respiration CO2 in the gas chamber after removing the outliers, based on the measurement deviation of the gas concentration detection device, to obtain the corrected soil respiration CO2 concentration value.

[0126] Flux determination module 54 is used to determine the soil respiration CO2 flux based on the corrected soil respiration CO2 concentration value, and based on the soil respiration CO2 flux... 12 CO2 flux and 13 CO2 flux, determine δ 13 C-flux.

[0127] In this exemplary embodiment, the gas concentration detection device contains a gas chamber. During soil respiration CO2 concentration detection, there is a gas discharge process, which causes a change in the soil respiration CO2 concentration. Before it stabilizes, the soil respiration CO2 concentration in the gas chamber will be inaccurate. Therefore, the effective data collected by detecting the amount of soil respiration CO2 in the gas chamber will be relatively more accurate.

[0128] In this exemplary embodiment, standard gas 12 CO2 concentration and 13 CO2 concentration calculation. Standard gas. 12 The true value of the total CO2 concentration was provided by the standard gas company, δ 13 The C value was determined using a stable isotope mass spectrometer. (The C value in the standard gas...) 12 CO2 concentration and 13 CO2 concentration values ​​can be obtained from known total [CO2] and δ 13 The value of C is obtained using the following formula:

[0129] ;in,

[0130] Where [CO2] is the total CO2 mixture ratio including all isotopes; f is the mixture ratio including all isotopes except [CO2]. 12 CO2] and [ 13 The proportion of other isotopes besides CO2 (0.00474); Ra is the molar ratio of light and heavy isotopes in the sample; R VPDB It is standard 13 C / 12 C molar ratio (0.0111797); δa is the carbon isotopic composition.

[0131] The standard gas measurement typically takes 10-15 minutes. 12 CO2, 13 CO2, δ 13The switching time for C is calculated separately. Based on the concentration curve during the standard gas measurement period, the data of the first 100 seconds is first removed. Starting from i=101, if the absolute value of the difference between the i-th value and the mean of all subsequent values ​​is less than the std standard deviation of all subsequent values, it is considered that the standard gas switching is normal from the i-th value, and the switching time t1 is calculated. 12 CO2, 13 CO2 and δ 13 The average switching times for C were 231.62±132.88, 144.49±49.15, and 102.26±3.17 s, respectively.

[0132] In this application, by correcting the measurement deviation of the gas concentration detection device and filtering the collected soil respiration CO2 data based on the gas chamber exhaust characteristics of the gas concentration detection device, effective collected data of soil respiration CO2 in the gas chamber are obtained. Based on the corrected soil respiration CO2 concentration value, the soil respiration CO2 flux is determined, and based on the soil respiration CO2 flux... 12 CO2 flux and 13 CO2 flux, determine δ 13 C flux is beneficial for removing data with large errors from the collected data and for bias correction, thereby improving soil respiration CO2 flux and δ¹⁴C flux. 13 C. Flux measurement accuracy.

[0133] Since the systems / devices described in the above embodiments of the present invention are systems / devices used to implement the methods of the above embodiments of the present invention, those skilled in the art can understand the specific structure and modifications of the systems / devices based on the methods described in the above embodiments of the present invention, and therefore will not be repeated here. All systems / devices used in the methods of the above embodiments of the present invention fall within the scope of protection of the present invention.

[0134] This invention provides a computer-readable storage medium storing soil respiration CO2 flux and δ 13 C-flux determination procedure, soil respiration CO2 flux and δ 13 When the C-flux determination program is executed by the processor, it realizes the soil respiration CO2 flux and δ as described in the above embodiments. 13 C. Flux determination method.

[0135] This invention provides an electronic device, including a memory, a processor, and soil respiration CO2 flux and δ stored in the memory and operable on the processor. 13 The C-flux determination procedure is executed by the processor to determine the soil respiration CO2 flux and δ. 13 When determining the C-flux, the soil respiration CO2 flux and δ-flux described in the above embodiments are implemented. 13C. Flux determination method.

[0136] In the description of this invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0137] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0138] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first and second features are in direct contact, or that they are in indirect contact through an intermediate medium. Furthermore, "above," "over," or "on top" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," or "beneath" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0139] In the description of this specification, the terms "one embodiment," "some embodiments," "embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0140] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make modifications, alterations, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for measuring soil respiration CO2 flux and δ¹⁸O₂ flux 13 The method for determining C-flux is characterized by... include: The measurement deviation of the gas concentration detection device is obtained by correcting the measurement deviation of the gas concentration detection device using a standard gas. The gas concentration detection device collects data on soil respiration CO2 levels, and filters the collected data based on the exhaust characteristics of the gas chamber of the gas concentration detection device to obtain valid data on soil respiration CO2 levels within the gas chamber. Specifically, the filtering of the collected soil respiration CO2 data based on the exhaust characteristics of the gas chamber of the gas concentration detection device to obtain valid data on soil respiration CO2 levels within the gas chamber includes: determining the curvature change nodes of the data curve when the gas concentration detection device measures soil respiration CO2 concentration based on the exhaust characteristics of the gas chamber of the gas concentration detection device; obtaining curvature change nodes where the curvature changes from negative to zero and from zero to positive; determining the curvature change nodes where the curvature changes from negative to zero and from zero to positive as the target curvature node of the data curve after the gas chamber is filled with soil respiration CO2; and determining the soil respiration CO2 concentration measurement data after determining the target curvature node as the valid data on soil respiration CO2 levels within the gas chamber. For outliers in the effective collected data of soil respiration CO2 in the gas chamber, a linear fitting or neural network model is used for quality control to remove the outliers. Based on the measurement deviation of the gas concentration detection device, the effective collected data of soil respiration CO2 in the gas chamber after removing the outliers are corrected for measurement deviation to obtain the corrected soil respiration CO2 concentration value. Based on the corrected soil respiration CO2 concentration value, the soil respiration CO2 flux is determined, and based on the soil respiration CO2 flux... 12 CO2 flux and 13 CO2 flux, determine δ 13 C-flux.

2. Soil respiration CO2 flux and δ as described in claim 1 13 The method for determining C-flux is characterized by... The measurement deviation of the gas concentration detection device is used to correct the effective collected data of soil respiration CO2 in the gas chamber, resulting in a corrected soil respiration CO2 concentration value, including: Based on the measurement deviation of the gas concentration detection device, please determine the concentration correction model; Based on the concentration correction model, the effective collected data of soil respiration CO2 in the gas chamber are corrected for measurement bias to obtain the corrected soil respiration CO2 concentration value; wherein, the concentration correction model includes: ; where X L s,T For the corrected soil respiration CO2 light isotope concentration value, X L 1,T The true molar concentration of light isotope standard gas 1, X L 2,T The true molar concentration of light isotope standard gas 2, X L s,M The measured values ​​of light isotope concentration of CO2 in soil respiration before correction, X L 1,M The measured molar concentration of light isotope standard gas 1, X L 2,M The molar concentration of light isotope standard gas 2 is measured. ; where X H s,T X represents the corrected soil respiration CO2 heavy isotope concentration value; H 1,T X represents the true molar concentration of heavy isotope standard gas 1; H 2,T X represents the true molar concentration of heavy isotope standard gas 2; H s,M The soil respiration CO2 heavy isotope concentration measurement before correction; X H 1,M X represents the measured molar concentration of heavy isotope standard gas 1; H 2,M The molar concentration of heavy isotope standard gas 2 is measured.

3. Soil respiration CO2 flux and δ as described in claim 1 13 The method for determining C-flux is characterized by... The determination of soil respiration CO2 flux based on the corrected soil respiration CO2 concentration value includes: Based on the corrected soil respiration CO2 concentration value and the concentration flux model, the soil respiration CO2 flux is determined; wherein, the concentration flux model includes: ;in, Fc is the soil respiration CO2 flux; V is the total volume of the system; P0 is the initial gas pressure in the gas chamber; W0 is the initial water vapor concentration in the gas chamber; R is Planck's constant; S is the soil measurement area; T0 is the initial air temperature in the gas chamber. This is the corrected soil respiration CO2 concentration value.

4. Soil respiration CO2 flux and δ as described in claim 1 13 The method for determining C-flux is characterized by... The CO2 flux based on soil respiration 12 CO2 flux and 13 CO2 flux, determine δ 13 C flux includes: Based on the soil respiration CO2 flux 12 CO2 flux and 13 CO2 flux and δ 13 C-flux model, determining δ 13 C flux; where δ 13 The C-flux model includes: ;in, Breathing for the soil 13 CO2 isotope flux; Breathing for the soil 12 CO2 isotope flux, R VPDB It is a constant.

5. Soil respiration CO2 flux and δ as described in claim 1 13 The method for determining C-flux is characterized by... Before correcting the measurement deviation of the effective collected data of soil respiration CO2 in the gas chamber based on the measurement deviation of the gas concentration detection device to obtain the corrected soil respiration CO2 concentration value, the method includes: The effective data of CO2 respiration in the soil within the gas chamber were linearly fitted to obtain the difference between the measured value and the fitted value. Based on the difference between the measured value and the fitted value, determine the average value and standard deviation of the difference; Data with a standard deviation exceeding a predetermined value are removed from the valid data collection of CO2 respiration in the air chamber.

6. A method for measuring soil respiration CO2 flux and δ¹⁸O₂. 13 C-flux determination device, characterized in that... include: The device deviation correction module is used to correct the measurement deviation of the gas concentration detection device using a standard gas, and to obtain the measurement deviation of the gas concentration detection device. The data acquisition module is used to collect data on soil respiration CO2 levels through the gas concentration detection device, and to filter the collected soil respiration CO2 data based on the exhaust characteristics of the gas chamber of the gas concentration detection device to obtain valid collected data on soil respiration CO2 levels within the gas chamber; wherein, the step of filtering the collected soil respiration CO2 data based on the exhaust characteristics of the gas chamber of the gas concentration detection device to obtain valid collected data on soil respiration CO2 levels within the gas chamber includes: determining, based on the exhaust characteristics of the gas chamber of the gas concentration detection device, whether the gas concentration detection device is used for soil respiration CO2 collection. The curvature change nodes of the data curve during respiration CO2 concentration measurement; based on the gas concentration detection device, the curvature change nodes of the data curve during soil respiration CO2 concentration measurement are obtained, specifically the curvature change nodes where the curvature changes from negative to zero and from zero to positive; these curvature change nodes are determined as the target curvature nodes of the data curve after the gas chamber is filled with soil respiration CO2; the soil respiration CO2 concentration measurement data after determining the target curvature node are considered valid data for the amount of soil respiration CO2 in the gas chamber. The data processing module is used to perform quality control on outliers in the effective data collection of soil respiration CO2 in the gas chamber using linear fitting or neural network models, and to remove the outliers. The data deviation correction module is used to correct the measurement deviation of the effective collected data of soil respiration CO2 in the gas chamber after removing the outliers, based on the measurement deviation of the gas concentration detection device, so as to obtain the corrected soil respiration CO2 concentration value. The flux determination module is used to determine the soil respiration CO2 flux based on the corrected soil respiration CO2 concentration value, and based on the soil respiration CO2 flux... 12 CO2 flux and 13 CO2 flux, determine δ 13 C-flux.

7. A computer-readable storage medium, characterized in that, It stores soil respiration CO2 flux and δ¹⁸O. 13 C-flux determination procedure, soil respiration CO2 flux and δ 13 When the C-flux determination program is executed by the processor, it realizes the soil respiration CO2 flux and δ as described in any one of claims 1-5. 13 C. Flux determination method.

8. An electronic device, characterized in that, This includes memory, a processor, and soil respiration CO2 flux and δ¹⁸O stored in memory and capable of running on the processor. 13 The C-flux determination procedure is executed by the processor to determine the soil respiration CO2 flux and δ. 13 When determining the C-flux, the soil respiration CO2 flux and δ-flux as described in any one of claims 1-5 are realized. 13 C. Flux determination method.

Images