A method and system for estimating aboveground and belowground net primary productivity of terrestrial ecosystems

Abstract

The present application provides a kind of terrestrial ecosystem aboveground and underground net primary productivity estimation method and system, comprising obtaining vegetation aboveground and underground net primary productivity observation data and resource availability data;According to the aboveground net primary productivity observation data, the comprehensive rate framework parameter is calibrated, and the aboveground net primary productivity simulation value is estimated based on the comprehensive rate framework parameter;Based on the vegetation aboveground and underground net primary productivity observation data, the aboveground and underground net primary productivity distribution proportion is estimated;The aboveground net primary productivity simulation value obtained based on the aboveground and underground net primary productivity distribution proportion is used to estimate the underground net primary productivity simulation value.The present application has good applicability;It can be used to simulate the temporal and spatial distribution law of vegetation productivity, stably evaluate the evolution dynamic of vegetation net primary productivity, help to evaluate global carbon model, further accurately evaluate regional carbon balance level, and deepen the understanding of complex dynamic of global carbon balance under changing climate conditions.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of ecology, and particularly relates to a method and system for estimating aboveground and underground net primary productivity of a terrestrial ecosystem. BACKGROUND

[0002] The net primary productivity (NPP) of vegetation in a terrestrial ecosystem refers to the net total amount of organic matter accumulated by vegetation through photosynthesis, and is one of important components of global terrestrial carbon cycle. In-depth understanding of the dynamic evolution process of the net primary productivity of vegetation can provide scientific basis and effective support for monitoring regional carbon budget, evaluating ecosystem function and formulating carbon management strategies. As an important link of the terrestrial carbon cycle, accurate estimation of the productivity process of vegetation is a key to predicting the carbon peak and carbon neutralization level under the condition of climate change, is a prerequisite and basis for reasonably evaluating regional carbon budget, and is a big focus of current research on carbon cycle.

[0003] In recent decades, the emergence of statistical models, remote sensing technologies and terrestrial ecosystem models has promoted significant progress in the quantification of global NPP. These methods mainly rely on the empirical relationship between NPP and predicted variables, or the theoretical assumption of photosynthesis process. However, there is a great difference in the NPP estimated by these models, and there is considerable uncertainty. In addition, the underground part of net productivity (BNPP) is the most uncertain part of global carbon cycle, but due to the limitations of observation difficulty and high cost, the exploration of it is still insufficient at present.

[0004] In view of this, how to propose a method for estimating the aboveground and underground net primary productivity of a terrestrial ecosystem, which can stably and simply estimate the spatial pattern of NPP and its components, has become a technical problem to be solved at present. SUMMARY

[0005] In view of the deficiencies in the prior art, based on the measured data of net primary productivity of ecosystem vegetation, according to the response relationship of the aboveground part of net productivity to different resource availability (water availability and light availability), and combining the aboveground and underground carbon distribution relationship of net primary productivity of vegetation, a method for estimating the aboveground and underground net primary productivity of a terrestrial ecosystem is proposed.

[0006] In order to solve the above problems, the technical scheme adopted by the present application is as follows:

[0007] A method for estimating the aboveground and underground net primary productivity of a terrestrial ecosystem comprises the following steps:

[0008] Step 1, obtaining vegetation aboveground and underground net primary productivity observation data and resource availability data, and dividing the obtained aboveground net primary productivity observation data into a calibration data set and a verification data set;

[0009] Step 2, calibrate the integrated rate framework parameters based on the aboveground net primary productivity observation data in the calibration dataset, and construct the aboveground net primary productivity estimation model based on the integrated rate framework parameters to estimate the aboveground net primary productivity simulation value;

[0010] Step 3, estimate the aboveground and belowground net primary productivity distribution ratio based on the vegetation aboveground and belowground net primary productivity observation data according to the functional balance theory;

[0011] Step 4, estimate the belowground net primary productivity simulation value based on the aboveground and belowground net primary productivity distribution ratio and the aboveground net primary productivity simulation value obtained in step 2.

[0012] Further, it further includes step 5: test the simulation accuracy of the aboveground net primary productivity simulation value and the belowground net primary productivity simulation value.

[0013] Further, the integrated rate framework parameters in step 2 are:

[0014]

[0015]

[0016] wherein, r is the integrated resource-limited rate of vegetation photosynthesis, ω i is the sensitivity of vegetation to different resource availabilities, x i is the normalized resource availability, wherein i represents different resource types, x 1 is the normalized energy availability, n is the total number of resource types.

[0017] Further, the aboveground and belowground net primary productivity distribution ratio in step 3 is:

[0018] Further, the aboveground and belowground net primary productivity distribution ratio in step 3 is:

[0019] wherein, is the belowground net primary productivity observation data, is the aboveground net primary productivity observation data; is the function related to the aboveground net primary productivity observation data.

[0020] Further, the belowground net primary productivity simulation value in step 4 is:

[0021] .

[0022] ​​Further, the step 5 selects the Nash efficiency coefficient to test the simulation accuracy of the simulated aboveground net primary productivity and the simulated belowground net primary productivity.

[0023] In another aspect, the present application provides a terrestrial ecosystem aboveground and belowground net primary productivity estimation system, comprising:

[0024] An observation data acquisition module is configured to acquire vegetation aboveground and belowground net primary productivity observation data and resource availability data, and divide the acquired aboveground net primary productivity observation data into a calibration dataset and a test dataset;

[0025] A first estimation module is configured to calibrate comprehensive rate framework parameters according to the aboveground net primary productivity observation data in the calibration dataset, and construct an aboveground net primary productivity estimation model based on the comprehensive rate framework parameters to estimate simulated aboveground net primary productivity;

[0026] A distribution proportion estimation module is configured to estimate the distribution proportion of aboveground and belowground net primary productivity according to the functional balance theory based on the vegetation aboveground and belowground net primary productivity observation data;

[0027] A second estimation module is configured to estimate simulated belowground net primary productivity based on the distribution proportion of aboveground and belowground net primary productivity and the acquired simulated aboveground net primary productivity;

[0028] A test module is configured to test the simulation accuracy of the simulated aboveground net primary productivity and the simulated belowground net primary productivity.

[0029] Compared with the prior art, the present application has the following beneficial effects:

[0030] Based on the actual observation data of vegetation net primary productivity, the present application proposes an explicit model for estimating aboveground and belowground net primary productivity, which has the characteristics of few parameters, simple structure and transparency, and thus has good applicability. The present application is simple and practical, and can be used to simulate the temporal and spatial distribution law of vegetation productivity, and to stably evaluate the evolution dynamics of vegetation net primary productivity. It is helpful for evaluating global carbon models, further accurately evaluating regional carbon budget levels, and deepening the understanding of the complex dynamics of global carbon balance under changing climate conditions. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor.

[0032] Figure 1A flow chart of the method of the embodiment of the present application;

[0033] Figure 2 A model simulation effect verification chart of the embodiment of the present application; DETAILED DESCRIPTION

[0034] To make the objectives, technical solutions and advantages of the present application clearer, the technical solutions of the present application will be described below in detail with reference to the drawings in the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0035] It should be noted that, in the description of the embodiments of the present application, the terms "comprise", "contain" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or device. Without more limitations, the element defined by the statement "comprising a" does not exclude the presence of another identical element in the process, method, article or device comprising the element. The above terms in the present application can be understood according to the specific meaning of the terms in the present application by those of ordinary skill in the art according to the specific circumstances.

[0036] The terms "first", "second" and the like in the present application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than that illustrated or described herein, and the objects distinguished by "first", "second" and the like are generally a category, and do not limit the number of objects, for example, the first object can be one or more. In addition, "and / or" means at least one of the connected objects, and the character " / ", generally means that the front and rear associated objects are in a "or" relationship.

[0037] Embodiment 1

[0038] The method for estimating aboveground and belowground net primary productivity of terrestrial ecosystems provided by the embodiment includes the following steps:

[0039] Step 1, obtaining vegetation aboveground and belowground net primary productivity observation data and resource availability data, and dividing the obtained aboveground net primary productivity observation data into calibration data set and verification data set;

[0040] The 688 ANPP sample points of the assembly were selected as research examples, of which 297 sample points had paired BNPP observation data (https: / / doi.org / 10.6084 / m9.figshare.27237795.v1). According to the latitude and longitude of the sample points, the corresponding meteorological data was extracted.

[0041] The resource availability considered in this embodiment is water and energy, and the multi-year average absorbed light and effective radiation (APAR) and multi-year average precipitation (MAP) are used to represent energy availability and water availability, respectively, and the obtained aboveground net primary productivity (ANPP) observation data set is divided into 481 calibration sample points and 207 test sample points;

[0042] Step 2, calibrate the comprehensive rate framework parameters according to the aboveground net primary productivity observation data in the calibration data set, and construct an aboveground net primary productivity estimation model based on the comprehensive rate framework parameters to estimate the aboveground net primary productivity simulation value;

[0043] According to the ANPP and normalized resource availability data in the calibration period, the comprehensive rate framework parameters are calibrated, and the expression is:

[0044]

[0045] In the formula, x 1 is the normalized energy availability, x 2 is the normalized water availability.

[0046] The aboveground net primary productivity estimation model is:

[0047]

[0048] Among them, A max is the maximum aboveground net primary productivity, is the aboveground net primary productivity simulation value.

[0049] Step 3, based on the observation data of aboveground and underground net primary productivity of vegetation, the aboveground and underground net primary productivity distribution ratio is estimated according to the functional balance theory;

[0050] The aboveground and underground net primary productivity distribution ratio is established according to the measured data as follows:

[0051]

[0052] Step 4, based on the aboveground and underground net primary productivity distribution ratio and the aboveground net primary productivity simulation value obtained in step 2, the underground net primary productivity simulation value is estimated.

[0053] Step 5, the simulation accuracy of the simulated value of the aboveground net primary productivity and the simulated value of the belowground net primary productivity is verified.

[0054] The evaluation index is selected as the Nash efficiency coefficient NSE, and the formula is as follows:

[0055]

[0056] In the formula, and are observation and simulation values. is the average value of , is the average value of , i = 1, 2,...,m);

[0057] The results show that the simulation of the aboveground net primary productivity ANPP of vegetation has an NSE of 0.71 in the calibration period and an NSE of 0.66 in the verification period (a). Figure 2 The simulation accuracy of the aboveground and belowground distribution ratio (BNPP:ANPP) can reach 0.86 (b). Figure 2 Further, the estimated ANPP is multiplied by the aboveground and belowground distribution ratio to indirectly estimate the BNPP, and the accuracy of the BNPP reaches 0.93, proving that the method has high closure.

[0058] It can be seen that the method for estimating the aboveground and belowground net primary productivity of a terrestrial ecosystem can effectively simulate the aboveground and belowground net primary productivity of vegetation and stably capture the spatial distribution characteristics thereof.

[0059] Embodiment 2

[0060] The embodiment provides a terrestrial ecosystem aboveground and belowground net primary productivity estimation system, which comprises:

[0061] An observation data acquisition module is configured to acquire vegetation aboveground and belowground net primary productivity observation data and resource availability data, and divide the acquired aboveground net primary productivity observation data into a calibration data set and a verification data set.

[0062] A first estimation module is configured to calibrate comprehensive rate framework parameters according to the aboveground net primary productivity observation data in the calibration data set, construct an aboveground net primary productivity estimation model based on the comprehensive rate framework parameters, and estimate an aboveground net primary productivity simulation value.

[0063] A distribution ratio estimation module is configured to estimate an aboveground and belowground net primary productivity distribution ratio according to a functional balance theory based on the vegetation aboveground and belowground net primary productivity observation data.

[0064] a second estimation module configured to estimate the simulated value of the underground NPP based on the above-ground underground NPP distribution ratio and the simulated value of the above-ground NPP;

[0065] a verification module configured to verify the simulation accuracy of the simulated value of the above-ground NPP and the simulated value of the underground NPP.

[0066] Those skilled in the art can clearly understand that the embodiments can be realized by means of software and necessary universal hardware platform, and of course can also be realized by hardware, through the above description of the embodiments. Based on such understanding, the above technical solutions can be embodied in the form of software product, which can be stored in a computer readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes a plurality of instructions to make a computer device (which can be a personal computer, server, or network device, etc.) execute the method described in each embodiment or some parts of the embodiment.

[0067] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, and not to limit it; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for some technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for estimating above- and below-ground net primary productivity of a terrestrial ecosystem, characterized by, The method comprises the following steps: Step 1, obtaining vegetation aboveground and belowground net primary productivity observation data and resource availability data, and dividing the obtained aboveground net primary productivity observation data into a calibration data set and a verification data set; Step 2, calibrating a comprehensive rate framework parameter according to the aboveground net primary productivity observation data in the calibration data set, and constructing an aboveground net primary productivity estimation model based on the comprehensive rate framework parameter to estimate aboveground net primary productivity simulation values; the comprehensive rate framework parameter is: wherein, r is the integrated resource limitation rate of photosynthesis of vegetation, ω i is the sensitivity of vegetation to different resource availabilities, x i is the normalized resource availability, wherein i denotes different resource categories, x 1 is the normalized energy availability, n is the total number of resource categories; Step 3, estimating an aboveground and belowground net primary productivity distribution ratio according to a functional balance theory based on the vegetation aboveground and belowground net primary productivity observation data; Step 4, estimating belowground net primary productivity simulation values based on the aboveground and belowground net primary productivity distribution ratio and the aboveground net primary productivity simulation values obtained in step 2.

2. The method according to claim 1, wherein, Further comprising step 5: verifying the simulation accuracy of the aboveground net primary productivity simulation values and the belowground net primary productivity simulation values.

3. The method according to claim 1, wherein, The aboveground net primary productivity estimation model is: wherein, A max is the maximum aboveground net primary productivity, is the aboveground net primary productivity simulation value.

4. The method according to claim 1, wherein, The distribution ratio of aboveground and belowground net primary productivity in step 3 Is: wherein, is the observed data for belowground net primary productivity, is the observed data for aboveground net primary productivity; is a function of the observed data for aboveground net primary productivity.

5. The method according to claim 4, wherein, The step 4 belowground net primary productivity simulation value is: 。 6. The method for estimating the net primary productivity above and under ground of a terrestrial ecosystem according to claim 2, wherein, In step 5, the Nash efficiency coefficient is selected to verify the simulation accuracy of the aboveground net primary productivity simulation values and the belowground net primary productivity simulation values.

7. A terrestrial ecosystem aboveground belowground net primary productivity estimation system characterized by, The method comprises the following steps: An observation data obtaining module is configured to obtain vegetation aboveground and belowground net primary productivity observation data and resource availability data, and divide the obtained aboveground net primary productivity observation data into a calibration data set and a verification data set; A first estimation module is configured to calibrate a comprehensive rate framework parameter according to the aboveground net primary productivity observation data in the calibration data set, and construct an aboveground net primary productivity estimation model based on the comprehensive rate framework parameter to estimate aboveground net primary productivity simulation values; A distribution ratio estimation module is configured to estimate an aboveground and belowground net primary productivity distribution ratio according to a functional balance theory based on the vegetation aboveground and belowground net primary productivity observation data; A second estimation module is configured to estimate belowground net primary productivity simulation values based on the aboveground and belowground net primary productivity distribution ratio and the aboveground net primary productivity simulation values obtained in step 2. A verification module is configured to verify the simulation accuracy of the aboveground net primary productivity simulation values and the belowground net primary productivity simulation values. The terrestrial ecosystem aboveground and belowground net primary productivity estimation system is configured to perform the steps in the terrestrial ecosystem aboveground and belowground net primary productivity estimation method of any one of claims 1-6.

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