Absorption amount estimation system, absorption amount estimation method, absorption amount estimation program, and calculation system

Abstract

To estimate a CO2 absorption amount based on forest evapotranspiration.SOLUTION: A precipitable water amount calculation unit 110 calculates a precipitable water amount of each grid mass for a three-dimensional grid above an observation area based on delay amount data and meteorological observation data. A potential evapotranspiration calculation unit 120 calculates a potential evapotranspiration vertically above each mesh square, which is a rectangular area, for a two-dimensional mesh on a surface of the observation area based on the precipitable water amount of each grid mass. A forest feature identification unit 130 identifies forest features for each forest area in the observation area based on a satellite image. An evapotranspiration ratio calculation unit 140 calculates an evapotranspiration ratio for each forest area based on the forest features. An absorption calculation unit 150 calculates an absorption amount of carbon dioxide for each forest area based on the potential evapotranspiration of the corresponding mesh mass and the evapotranspiration ratio.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This disclosure relates to a technology for estimating the amount of carbon dioxide (CO2) absorbed based on the evapotranspiration rate of forests. [Background technology]

[0002] 85 percent of Japan's land area of ​​400,000 square kilometers is covered by forests, and in Japan, forests are a valuable source of carbon dioxide (CO2), which is a cause of global warming.

[0003] The amount of CO2 absorbed by forests is not actually observed, but is calculated based on forest records. A forest register is a ledger containing various information about forests. Specifically, it includes information such as location, owner, area, type, timber volume, and growth rate.

[0004] Forest registers are created by adding aerial photographs and hearsay information from landowners to maps produced by the Geospatial Information Authority of Japan using public surveys. Furthermore, the information in the forest register is not surveyed, the forest boundaries are unclear, and the information is not updated. These circumstances hinder efficiency in areas such as the buying and selling of forests, the consolidation of small-scale forest landowners, and the intensification of forestry operations.

[0005] Patent Document 1 discloses a method for calculating CO2 absorption using forest register data. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2012-58772 [Overview of the project] [Problems that the invention aims to solve]

[0007] This disclosure aims to enable the estimation of CO2 absorption based on forest evapotranspiration. [Means for solving the problem]

[0008] The absorption estimation system in this disclosure is A precipitable water calculation unit calculates the precipitable water amount for each grid cell in the three-dimensional grid based on delay data indicating the slant direction delay amount of each grid point for a three-dimensional grid above the observation area, and meteorological observation data indicating the meteorological observation amount for each region of the observation area. Based on the amount of precipitable water in each grid cell, an evapotranspiration calculation unit calculates the evapotranspiration vertically above each rectangular mesh cell for a two-dimensional mesh on the surface of the observation area. A forest feature identification unit identifies the characteristics of each forest area within the observation region based on satellite images showing the observation region, For each forest area, an evapotranspiration ratio calculation unit calculates the evapotranspiration ratio, which is the ratio of evaporation from the soil to transpiration from trees, based on the characteristics of the forest. The system includes an absorption calculation unit that calculates the amount of carbon dioxide absorbed for each forest area based on the evapotranspiration rate of the corresponding mesh mass and the evapotranspiration ratio. [Effects of the Invention]

[0009] According to this disclosure, the amount of CO2 absorbed can be estimated based on the amount of evapotranspiration in a forest. [Brief explanation of the drawing]

[0010] [Figure 1] Configuration diagram of the absorption amount estimation system 200 in Embodiment 1. [Figure 2] Configuration diagram of the absorption amount estimation device 100 in Embodiment 1. [Figure 3] Configuration diagram of the positioning augmentation system 210 in Embodiment 1. [Figure 4] Flowchart of the absorption amount estimation method in Embodiment 1. [Figure 5]Flowchart of step S110 in Embodiment 1. [Figure 6] Explanatory drawing of step S110 in Embodiment 1. [Figure 7] Conceptual diagram of the atmospheric water balance method in Embodiment 1. [Figure 8] Diagram showing satellite image 231 in Embodiment 1. [Figure 9] Diagram showing forest area 232 in Embodiment 1. [Figure 10] Conceptual diagram of motion stereo in Embodiment 1. **Mode for Carrying Out the Invention**

[0011] In the embodiments and the drawings, the same elements or corresponding elements are denoted by the same reference numerals. The description of the elements denoted by the same reference numerals as the described elements is omitted or simplified as appropriate. The arrows in the figures mainly indicate the flow of data or the flow of processing.

[0012] Embodiment 1. The absorption amount estimation system 200 will be described based on FIGS. 1 to 10.

[0013] ***Description of Configuration*** Based on FIG. 1, the configuration of the absorption amount estimation system 200 will be described. The absorption amount estimation system 200 includes a positioning enhancement system 210, a receiver network 220, an observation satellite 230, and an absorption amount estimation device 100. The positioning enhancement system 210 is a system for positioning enhancement services. A specific example of the positioning enhancement service is the centimeter-level positioning enhancement service (CLAS). The receiver network 220 is a plurality of receivers 221 for a satellite positioning system and a positioning enhancement system 210. The satellite positioning system is called the Global Navigation Satellite System (GNSS). A specific example of the satellite positioning system is the Global Positioning System (GPS). Observation satellite 230 is an observation satellite. A specific example of observation satellite 230 is a SAR satellite. A SAR satellite is an artificial satellite equipped with synthetic aperture radar (SAR). The absorption estimation device 100 estimates the amount of carbon dioxide absorbed in each forest area.

[0014] The configuration of the absorption amount estimation device 100 will be explained based on Figure 2. The absorption amount estimation device 100 is a computer equipped with hardware such as a processor 101, memory 102, auxiliary storage device 103, communication device 104, and input / output interface 105. These hardware components are connected to each other via signal lines.

[0015] The processor 101 is an IC that performs arithmetic operations and controls other hardware. For example, the processor 101 is a CPU. IC is an abbreviation for Integrated Circuit. CPU is an abbreviation for Central Processing Unit.

[0016] Memory 102 is a volatile or non-volatile storage device. Memory 102 is also called main memory. For example, memory 102 is RAM. Data stored in memory 102 is saved to auxiliary storage device 103 as needed. RAM is an abbreviation for Random Access Memory.

[0017] The auxiliary storage device 103 is a non-volatile storage device. For example, the auxiliary storage device 103 is a ROM, HDD, flash memory, or a combination thereof. Data stored in the auxiliary storage device 103 is loaded into memory 102 as needed. ROM is an abbreviation for Read Only Memory. HDD is an abbreviation for Hard Disk Drive.

[0018] The communication device 104 is a receiver and transmitter. For example, the communication device 104 is a communication chip or NIC. Communication of the absorption amount estimation device 100 is performed using the communication device 104. NIC is an abbreviation for Network Interface Card.

[0019] The input / output interface 105 is a port to which input and output devices are connected. For example, the input / output interface 105 is a USB terminal, the input devices are a keyboard and mouse, and the output device is a display. Input and output of the absorption amount estimation device 100 are performed using the input / output interface 105. USB is an abbreviation for Universal Serial Bus.

[0020] The absorption amount estimation device 100 includes elements such as a precipitable water amount calculation unit 110, an evapotranspiration rate calculation unit 120, a forest characteristic identification unit 130, an evapotranspiration ratio calculation unit 140, and an absorption amount calculation unit 150. These elements are implemented by software.

[0021] The auxiliary storage device 103 stores an absorption estimation program that enables the computer to function as a precipitable water amount calculation unit 110, an evapotranspiration rate calculation unit 120, a forest characteristic identification unit 130, an evapotranspiration ratio calculation unit 140, and an absorption amount calculation unit 150. The absorption estimation program is loaded into memory 102 and executed by the processor 101. The auxiliary storage device 103 also stores the operating system. At least a portion of the OS is loaded into memory 102 and executed by the processor 101. Processor 101 runs the absorption amount estimation program while executing the OS. OS is an abbreviation for Operating System.

[0022] The input and output data of the absorption amount estimation program are stored in the storage unit 190. Memory 102 functions as a storage unit 190. However, storage devices such as auxiliary storage device 103, registers in the processor 101, and cache memory in the processor 101 may function as a storage unit 190 instead of memory 102, or together with memory 102.

[0023] The absorption amount estimation device 100 may include multiple processors that replace the processor 101.

[0024] The absorption estimation program can be recorded (stored) in a computer-readable format on a non-volatile recording medium such as an optical disc or flash memory.

[0025] The configuration of the positioning augmentation system 210 will be explained based on Figure 3. The positioning augmentation system 210 comprises multiple positioning satellites 211, multiple electronic reference points 212, information generation equipment 213, and a quasi-zenith satellite 214. Each positioning satellite 211 transmits ranging signals. The information obtained by receiving these ranging signals is called "positioning information." (1) Because the ranging signal passes through the ionosphere and troposphere, errors in positioning information occur due to ionospheric delay and tropospheric delay. The direction from the receiver to each satellite is called the "slant direction." The ionospheric delay and tropospheric delay in the slant direction are called "slant wet delays (SWD)". Slant-direction delay is also called "line-of-sight tropospheric delay." (2) The information generation equipment 213 calculates the error amount of the positioning information based on multiple positioning information obtained from multiple electronic reference points 212, and generates positioning augmentation information based on the error amount of the positioning information. Positioning augmentation information is information used to correct errors in the positioning signal. Note that there are approximately 1,300 electronic reference points 212 installed throughout Japan, and positioning augmentation information is generated using information obtained from approximately 250 electronic reference points 212. (3) Positioning augmentation information is distributed to user terminals 215 in various locations via Quasi-Zenith Satellite System 214. The positioning augmentation information is compressed and distributed using the L6 signal. (4) The user terminal 215 receives ranging signals from each positioning satellite 211 to obtain positioning information and corrects the positioning information using positioning augmentation information. The user terminal 215 then performs positioning using the corrected positioning information.

[0026] ***Explanation of operation*** The operating procedure of the absorption amount estimation system 200 corresponds to the absorption amount estimation method. Furthermore, the operating procedure of the absorption amount estimation device 100 corresponds to the processing procedure performed by the absorption amount estimation program.

[0027] Based on Figure 4, the method for estimating absorption will be explained. In step S110, the precipitable water calculation unit 110 calculates the precipitable water for each grid cell in the three-dimensional grid 222 above the observation area based on the delay data and meteorological observation data. A specific example of the observation area is Japan.

[0028] The three-dimensional grid 222 is predefined. For example, each grid cell is a cube with sides of 250 meters. Also, the height of the three-dimensional grid 222 from the Earth's surface is 11 kilometers.

[0029] Each cell in the 222-dimensional grid is called a "grid cell." Each intersection point of the three-dimensional grid 222 is called a "grid point".

[0030] The delay data represents the slant-direction delay for each grid point. Meteorological observation data is data that shows the meteorological observation quantities for each region within the observation area. Meteorological observation quantities are various values ​​observed regarding weather. Specific examples of meteorological observation quantities include temperature and atmospheric pressure.

[0031] The data showing the amount of precipitable water for each grid cell is called "precipitable water data."

[0032] The procedure for step S110 will be explained based on Figures 5 and 6. In Figure 6, the dotted lines with arrows represent the slant direction. Each circle on the dotted line with an arrow represents precipitable water. Receivers 221 are located at various points in the observation area (Japan). Only one receiver 221 is assigned a code, and the codes of other receivers 221 are omitted.

[0033] In step S111, each receiver 221 calculates the slant direction delay amount for each positioning satellite 211.

[0034] Specifically, each receiver 221 receives ranging signals from each positioning satellite 211 to obtain positioning information and receives positioning augmentation information from the quasi-zenith satellite 214. Then, each receiver 221 performs positioning calculations for each positioning satellite 211 based on the positioning augmentation information and positioning information, and calculates the slant direction delay amount based on the positioning augmentation information and positioning residual.

[0035] In step S112, the precipitation amount calculation unit 110 acquires the slant direction delay amount calculated for each positioning satellite 211 by each receiver 221. For example, the precipitable water amount calculation unit 110 receives the slant direction delay amount for each positioning satellite 211 from each receiver 221.

[0036] Next, the precipitable water amount calculation unit 110 represents the precipitable water amount distribution in three dimensions by performing tomographic analysis processing using multiple acquired slant direction delay amounts. Specifically, the precipitable water amount calculation unit 110 performs tomographic analysis processing incorporated into methods such as those described in reference (A). Literature (A): Ding et al. (2018, AMT) “A new approach for GNSS tomography from a few GNSS stations”

[0037] In step S113, the precipitation calculation unit 110 acquires meteorological observation data. For example, the precipitable water calculation unit 110 receives weather observation data from a server that manages weather observation data.

[0038] The precipitable water calculation unit 110 then calculates the precipitable water for each grid cell based on the slant direction delay amount of each grid point and the meteorological observation data (surface pressure, temperature) for each region.

[0039] Returning to Figure 4, we will continue the explanation from step S120. In step S120, the evapotranspiration calculation unit 120 calculates the evapotranspiration vertically above each rectangular mesh cell for a two-dimensional mesh of the surface of the observation area, based on the amount of precipitable water in each grid cell. Evapotranspiration is the sum of evaporation from the soil and transpiration from the vegetation. The two-dimensional mesh corresponds to the bottom surface of the three-dimensional grid 222. Each individual cell in a two-dimensional mesh is called a "mesh cell." Each intersection point of a two-dimensional mesh is called a "mesh point."

[0040] The evapotranspiration rate for each mesh mass is calculated by method (1) or method (2).

[0041] Method (1) for calculating the evapotranspiration rate (ET) for each mesh mass is described below. Method (1) is the method disclosed in reference (1). Reference (1): Makito Mori, et al., "Estimation of daily evapotranspiration using the relationship between GPS-measured precipitation and surface temperature," 2007, Journal of the Japanese Society of Agricultural Engineering, Graduate School of Agriculture, Kyushu University

[0042] The evapotranspiration rate (ET) for each mesh mass is calculated as follows. First, the precipitable water amount calculation unit 110 sums the precipitable water amounts PWV of the grid squares arranged in the vertical direction to calculate the precipitable water amount PWV S Calculate. Precipitable volume PWV S This represents the average precipitable water amount in the zenith direction and corresponds to the evapotranspiration rate (ET) of the mesh mass. Next, the precipitable water amount calculation unit 110 calculates the precipitable water amount PWVS Multiply by a coefficient to obtain the surface vapor pressure e S . The coefficient is tuned by performing comparative analysis and regression analysis using meteorological observation values. A specific example of the formula for the monthly average precipitable water vapor PWV S is shown below.

[0043] [Number]

[0044] Then, the precipitable water calculation unit 110 calculates the evapotranspiration amount ET by calculating the Penman formula with the surface vapor pressure e S substituted as "e a ". The Penman formula is expressed as follows.

[0045] [Number]

[0046] f(u2) is a wind speed function and is expressed as follows. f(u2)=0.26(1 + 0.537u2)

[0047] "R n " is the net radiation amount. "G" is the ground heat flux. "T a " is the surface air temperature. e sat (T a ) is the saturation vapor pressure with respect to T a . "e a " is the surface vapor pressure. "u2" is the wind speed at an altitude of 2 meters. "Δ" is the gradient of the saturation vapor pressure curve. "γ" is the psychrometric constant.​​​​​The above weather data is calculated using weather elements observed at weather stations near the grid cell in question. The specific weather elements are atmospheric pressure, wind speed, temperature, ground water vapor pressure, and sunshine duration, and each weather element is shown as a daily average value. GPS precipitation is calculated based on GNSS atmospheric delay, atmospheric pressure, and temperature data from the weather station.

[0049] Net radiation R n Since it is rarely measured on a daily basis, it is calculated by performing the following formula.

[0050]

number

[0051] "S0" represents the horizontal solar radiation outside the atmosphere. "n" represents the amount of daylight. "N" represents the illumination time. "α" stands for albedo. "σ" is the Stefan-Boltzmann constant. "a" and "b" are constants for the sunshine meter.

[0052] Method (2) for calculating the evapotranspiration amount E corresponding to the evapotranspiration position of each mesh mass is explained. Method (2) is the method disclosed in reference (2). Reference (2) discloses a method for estimating evapotranspiration at short intervals of less than one month. Reference (2): Kazuaki Man, "Establishment of an evapotranspiration estimation method applying GPS precipitable water to the atmospheric water balance method," 2012, Grants-in-Aid for Scientific Research, Kyoto University Research Institute Figure 7 illustrates the concept of the atmospheric water balance method.

[0053] The evapotranspiration E for each mesh cell is calculated as follows: First, the precipitable water amount calculation unit 110 calculates the amount of water W by summing the slant direction delays of the grid masses arranged in the height direction. The amount of water W represents the amount of water in the atmospheric column. Furthermore, the precipitable water amount calculation unit 110 calculates the advection model by using the slant direction delay amount of the grid masses arranged in the height direction as a parameter, thereby determining the advection flow rate ∇ H Calculate Q. Transfer rate ∇ H Q represents the transfer rate from the entire side of the atmospheric column. The advection model is represented by an advection vector and a turbulence term. The advection vector approximates the advection component with a linear equation of positional information. An appropriate spatial spacing (grid / mesh size) is necessary to determine the advection vector. A 3D grid 222 can serve as an alternative to the advection model. Furthermore, the precipitable water calculation unit 110 acquires the precipitation amount P. The precipitation amount P is the amount of precipitation observed at the time corresponding to the slant direction delay. For example, the precipitation amount P is included in the meteorological observation data. The precipitable water amount calculation unit 110 then calculates the precipitation amount P, the water content W, and the transfer rate ∇ H The evapotranspiration E is calculated by summing up Q.

[0054] The evapotranspiration rate E for each mesh can be expressed by the following formula. E = P + W + ∇ H Q

[0055] Returning to Figure 4, we will continue the explanation from step S130. In step S130, the forest feature identification unit 130 identifies the forest features for each forest area in the observation region based on the satellite image 231. Satellite image 231 is an image showing the observed area and was obtained by observation satellite 230. A forest area is an area where forests exist. Each area corresponds to a grid cell. Specific forest characteristics include tree height, tree species, and forest boundaries. These forest characteristics are also referred to as "land classification."

[0056] The procedure for step S130 is described below. Figure 8 shows satellite image 231 divided into two-dimensional meshes. Dark shading represents forests, and light shading represents non-forest areas. Non-forest areas include logged areas. First, the forest feature identification unit 130 acquires satellite imagery 231. For example, the forest feature identification unit 130 receives satellite imagery 231 from the observation satellite 230. Alternatively, the forest feature identification unit 130 receives observation data from the observation satellite 230 and generates satellite imagery 231 using the observation data. Next, the forest feature identification unit 130 divides the satellite image 231 into a two-dimensional mesh.

[0057] Figure 9 shows multiple forest areas 232. Each shaded square represents a forest area. Next, the forest feature identification unit 130 identifies the mesh squares corresponding to each forest area by analyzing the satellite image 231.

[0058] Figure 10 illustrates the concept of motion stereo. The forest feature identification unit 130 then identifies the forest characteristics of each forest area by analyzing satellite images 231. For example, the forest feature identification unit 130 identifies the height of trees as follows: First, the forest feature identification unit 130 measures the height of the tree canopy using baseline information from satellite imagery 231. The forest feature identification unit 130 also obtains the height of the ground surface excluding trees from a prepared digital elevation model (DEM). The DEM may be stored in the storage unit 190 or managed on an external server. The forest feature identification unit 130 then calculates the height of the trees by subtracting the ground surface height from the height of the tree canopy. Measuring the height of the tree canopy allows for the reflection of the latest growth of the trees. Forest characteristics may be identified using artificial intelligence (AI) or deep learning techniques.

[0059] Returning to Figure 4, we will continue the explanation from step S140. In step S140, the evapotranspiration ratio calculation unit 140 calculates the evapotranspiration ratio for each forest area based on the characteristics of the forest. The evapotranspiration ratio is the ratio of evaporation from the soil to transpiration from trees. Furthermore, 85 percent of Japan's land area is covered by forests. And, for example, there are many areas consisting solely of forests within a diameter of 30 to 60 kilometers. This range corresponds to the measurement range of precipitable water by a single receiver. Therefore, the amount of transpiration can be approximated to the evapotranspiration rate, and the output of the evapotranspiration ratio calculation unit 140 may be approximated to 1. The following description includes information on the planted forests where thinning has taken place, as well as the surrounding villages and roads.

[0060] For example, the evapotranspiration ratio calculation unit 140 calculates the area ratio of forested areas to non-forested areas for each mesh cell based on the forest characteristics (tree height, tree type, and forest boundary) obtained by the forest characteristic identification unit 130. The calculated area ratio becomes the evapotranspiration ratio. Non-forest areas include logging areas, villages, and roads.

[0061] In step S150, the absorption amount calculation unit 150 calculates the amount of carbon dioxide (CO2) absorbed for each forest area based on the evapotranspiration rate and evapotranspiration ratio of the corresponding mesh mass.

[0062] The amount of CO2 absorbed by each forest area has the following relationship with various types of information. Transpiration rate ∝ Photosynthesis rate ∝ CO2 absorption rate

[0063] Therefore, the amount of CO2 absorbed by each forest area is calculated as follows: First, the absorption calculation unit 150 selects the evapotranspiration rate of the mesh mass corresponding to the forest area from the evapotranspiration rate calculated in step S120. Furthermore, the absorption calculation unit 150 selects the evapotranspiration ratio of the forest area from the evapotranspiration ratio calculated in step S140. Next, the absorption amount calculation unit 150 calculates the amount of evaporation by multiplying the selected evapotranspiration position by the selected evapotranspiration ratio. The absorption amount calculation unit 150 then calculates the CO2 absorption amount by multiplying the calculated transpiration amount by a proportional parameter (coefficient).

[0064] The proportionality parameters (coefficients) are tuned as follows: It is generally known that transpiration and CO2 absorption are proportional, based on the principles of photosynthesis. The proportionality parameters (coefficients) are obtained from a table based on factors such as tree type (broadleaf or coniferous, etc.), tree height, and foliage. This table is then tuned based on commonly known calculation methods.

[0065] The following web pages (a-c) disclose information regarding CO2 absorption. (a)https: / / kids.gakken.co.jp / kagaku / eco110 / ecology0070 / (b) https: / / www.pref.wakayama.lg.jp / prefg / 032000 / gakusyu / program / tyugakko_d / fil / tyupro1-5.pdf (c)http: / / www.nilim.go.jp / lab / ddg / naiyo / co2 / co2.html

[0066] The absorption calculation unit 150 then outputs the amount of carbon dioxide absorbed in each forest area. For example, the absorption calculation unit 150 displays the amount of carbon dioxide absorbed in each forest area on the display. For example, if observations are conducted for one month, the amount of carbon dioxide absorbed by the forest during that month will be displayed on the screen.

[0067] ***Effects of Embodiment 1*** Embodiment 1 allows for the estimation of CO2 absorption based on the amount of forest transpiration. Therefore, it is possible to "visualize" and "quantify" the amount of CO2 absorption.

[0068] Embodiment 1 efficiently estimates CO2 absorption with high accuracy by utilizing various artificial satellites capable of observing data with all-weather coverage and wide-area uniformity. Furthermore, since Embodiment 1 is scalable and can be calculated using the same criteria regardless of region or area, it will contribute to the crediting (calculation of compensation) of forest CO2 absorption globally in the future.

[0069] ***Supplement to Embodiment 1*** The absorption estimation system 200 can be used as a calculation system for determining the amount of precipitable water and the evapotranspiration rate.

[0070] Embodiment 1 is an example of a preferred embodiment and is not intended to limit the technical scope of this disclosure. Embodiment 1 may be implemented in part or in combination with other embodiments. The procedure described using flowcharts, etc., may be modified as appropriate.

[0071] The absorption amount estimation device 100 may be implemented using two or more devices. The "parts" that make up the absorption amount estimation device 100 may be implemented using software, hardware, firmware, or a combination thereof. The term "part" in the absorption amount estimation device 100 may be read as "processing," "process," "circuit," or "circuit." [Explanation of Symbols]

[0072] 100 Absorption amount estimation device, 101 Processor, 102 Memory, 103 Auxiliary storage device, 104 Communication device, 105 Input / Output interface, 110 Precipitable water amount calculation unit, 120 Evapotranspiration rate calculation unit, 130 Forest feature identification unit, 140 Evapotranspiration ratio calculation unit, 150 Absorption amount calculation unit, 190 Storage unit, 200 Absorption amount estimation system, 210 Positioning augmentation system, 211 Positioning satellite, 212 Electronic reference point, 213 Information generation equipment, 214 Quasi-zenith satellite, 215 User terminal, 220 Receiver network, 221 Receiver, 222 Three-dimensional grid, 230 Observation satellite, 231 Satellite image, 232 Forest area.

Claims

1. a precipitable water mass calculation unit that calculates the precipitable water mass of each grid point relative to the three-dimensional grid above an observation area based on delay amount data that indicates the slant direction delay amount of each grid point relative to the three-dimensional grid above the observation area and meteorological observation data that indicates meteorological observation amounts for each region of the observation area; a potential evapotranspiration calculation unit that calculates potential evapotranspiration vertically above each mesh mass, which is a rectangular area, for a two-dimensional mesh on the surface of the observation area based on the precipitable water content of each grid mass; a forest characteristic identification unit that identifies forest characteristics for each forest area in the observation area based on a satellite image capturing the observation area; an evapotranspiration ratio calculation unit that calculates an evapotranspiration ratio, which is the ratio of the amount of evaporation from the soil to the amount of transpiration from the trees, for each forest area based on the characteristics of the forest; an absorption amount calculation unit that calculates the amount of carbon dioxide absorption for each forest area based on the potential evapotranspiration of the corresponding mesh mass and the evapotranspiration ratio; An absorption amount estimation system comprising:

2. The absorption amount estimation system further comprises: a plurality of positioning satellites that transmit ranging signals; a plurality of receivers disposed at different points in the observation area; Each of the plurality of receivers calculates a slant direction delay amount for each positioning satellite; The precipitable water vapor calculation unit projects each slant delay amount onto each grid point to calculate the slant delay amount of each grid point, and generates the delay amount data. The absorption amount estimation system according to claim 1 .

3. The forest characteristic identification unit divides the satellite image into two-dimensional meshes, identifies mesh masses corresponding to each forest area by analyzing the satellite image, and identifies forest characteristics of each forest area by analyzing the satellite image. The absorption amount estimation system according to claim 1 or 2.

4. The absorption amount calculation unit calculates the amount of transpiration by multiplying the potential evapotranspiration by the evapotranspiration ratio, and calculates the amount of absorption by multiplying the calculated amount of transpiration by a proportionality parameter. The absorption amount estimation system according to any one of claims 1 to 3.

5. Calculating the amount of precipitable water at each grid point for the three-dimensional grid based on delay data indicating the amount of slant delay at each grid point for the three-dimensional grid above the observation area and meteorological observation data indicating meteorological observation amounts for each region of the observation area; Based on the amount of precipitable water at each grid mass, a potential evapotranspiration vertically above each mesh mass, which is a rectangular area, is calculated for a two-dimensional mesh on the surface of the observation area; Identifying forest characteristics for each forest area in the observation area based on satellite images of the observation area; For each forest area, the evapotranspiration ratio, which is the ratio of evaporation from the soil to transpiration from the trees, is calculated based on the characteristics of the forest. For each forest area, the amount of carbon dioxide absorbed is calculated based on the potential evapotranspiration of the corresponding mesh mass and the evapotranspiration ratio. Absorption estimation method.

6. a precipitable water mass calculation unit that calculates the precipitable water mass of each grid point relative to the three-dimensional grid above an observation area based on delay amount data that indicates the slant direction delay amount of each grid point relative to the three-dimensional grid above the observation area and meteorological observation data that indicates meteorological observation amounts for each region of the observation area; a potential evapotranspiration calculation unit that calculates potential evapotranspiration vertically above each mesh mass, which is a rectangular area, for a two-dimensional mesh on the surface of the observation area based on the precipitable water content of each grid mass; a forest characteristic identification unit that identifies forest characteristics for each forest area in the observation area based on a satellite image capturing the observation area; an evapotranspiration ratio calculation unit that calculates an evapotranspiration ratio, which is the ratio of the amount of evaporation from the soil to the amount of transpiration from the trees, for each forest area based on the characteristics of the forest; an absorption amount calculation unit that calculates the amount of carbon dioxide absorption for each forest area based on the potential evapotranspiration of the corresponding mesh mass and the evapotranspiration ratio, Absorption estimation program to make the computer function.

7. a precipitable water mass calculation unit that calculates the precipitable water mass of each grid point relative to the three-dimensional grid above the observation area based on delay amount data that indicates the slant direction delay amount of each grid point relative to the three-dimensional grid above the observation area and meteorological observation data that indicates meteorological observation amounts in each region of the observation area; A calculation system comprising:

8. a precipitable water mass calculation unit that calculates the precipitable water mass of each grid point relative to the three-dimensional grid above an observation area based on delay amount data that indicates the slant direction delay amount of each grid point relative to the three-dimensional grid above the observation area and meteorological observation data that indicates meteorological observation amounts for each region of the observation area; a potential evapotranspiration calculation unit that calculates potential evapotranspiration vertically above each mesh mass, which is a rectangular area, for a two-dimensional mesh on the surface of the observation area based on the precipitable water content of each grid mass; A calculation system comprising:

9. The calculation system further comprises: a plurality of positioning satellites that transmit ranging signals; a plurality of receivers disposed at different points in the observation area; Each of the plurality of receivers calculates a slant direction delay amount for each positioning satellite; The precipitable water vapor calculation unit projects each slant delay amount onto each grid point to calculate the slant delay amount of each grid point, and generates the delay amount data.

9. A calculation system according to claim 7 or claim 8.

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