JPH07333129A - Gas flux measuring method and apparatus - Google Patents
Gas flux measuring method and apparatusInfo
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- JPH07333129A JPH07333129A JP12216294A JP12216294A JPH07333129A JP H07333129 A JPH07333129 A JP H07333129A JP 12216294 A JP12216294 A JP 12216294A JP 12216294 A JP12216294 A JP 12216294A JP H07333129 A JPH07333129 A JP H07333129A
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- gas
- concentration
- diffusion
- diffusion medium
- chamber
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Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、ガスフラックスを長期
間にわたって連続測定し得る方法及び装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus capable of continuously measuring gas flux over a long period of time.
【０００２】[0002]
【従来の技術】近年、地球環境の保護と資源の有効利用
が重要視されている中で、土壌、水面等から放出される
二酸化炭素ガスやメタンガスなどの放出量の調査・監視
が世界各地で行われている。また、生体系の調査等に当
たっては、植物葉等から放出されるガスやそこに吸収さ
れるガスの量の測定が行われる。2. Description of the Related Art In recent years, with the importance of protecting the global environment and effective use of resources, research and monitoring of the amount of carbon dioxide gas, methane gas, etc. released from soil, water surface, etc., has been conducted all over the world. Has been done. Further, in the investigation of biological systems, the amount of gas released from plant leaves and the amount of gas absorbed therein is measured.
【０００３】従来のガスフラックス測定方法には、大別
して、（ｉ）物質収支を基礎としたチェンバー法と（ｉ
ｉ）物質輸送を基礎とした微細気象学的方法がある。The conventional gas flux measuring methods are roughly classified into (i) a chamber method based on mass balance and (i)
i) There are micrometeorological methods based on mass transport.
【０００４】前記のチェンバー法は、ガス交換面に筒型
や箱型のチェンバー（容器）を接合し、その空洞内にガ
スを導き、当該チェンバー内のガス濃度変化から、ガス
フラックス（ガス交換速度）を求めるものである。この
方法は、物質収支に基づいているため、フラックス自体
の測定は、原理上も実際上も簡単かつ正確に行うことが
できる。In the above-mentioned chamber method, a cylindrical or box-shaped chamber (container) is joined to a gas exchange surface, gas is introduced into the cavity, and a gas flux (gas exchange rate) is determined from the change in gas concentration in the chamber. ). Since this method is based on mass balance, the flux itself can be measured easily and accurately in principle and in practice.
【０００５】しかし、チェンバー法のうちで密閉容器を
用いる方法（密閉法）では、時間と共に容器内のガス濃
度が通常の環境濃度より上昇する（又は低下する）た
め、ガス発生量（又は、ガス吸収量）自体が影響される
ようになる場合がある。例えば、土壌から放出される二
酸化炭素の測定では、ソースとなる微生物の活動が影響
を受けるため、その問題が派生する。したがって、この
方法では、間欠的な排気処置等の特別な手段を講じない
限り、長期間にわたってガスフラックスを正しく測定す
ることはできない。However, in the chamber method using a closed container (closed method), the gas concentration in the container rises (or decreases) from the normal environmental concentration over time, so that the gas generation amount (or gas) is increased. The absorption amount itself may be affected. For example, the measurement of carbon dioxide released from soils creates that problem because it affects the activity of the source microorganisms. Therefore, this method cannot accurately measure the gas flux for a long period unless special measures such as intermittent exhaust treatment are taken.
【０００６】チェンバー法のうちで容器内に周囲空気を
導いて通気させながら測定を行う方法（通気法）によれ
ば、そのような問題を回避することができる。[0006] According to the method (ventilation method) of the chamber method in which ambient air is introduced into the container to ventilate it, such a problem can be avoided.
【０００７】しかし、通気流量が少なすぎるとそれがガ
スフラックスを律速し、また、逆に多すぎると負圧によ
る吸い出し等の影響でいずれも正しい測定値は得られな
い。したがって、適切な通気流量を予め求めておく必要
があるが、容器の大きさや形状等にも依存するため、こ
れを決めるのは必ずしも容易ではない。However, if the flow rate of ventilation is too small, it limits the gas flux, while if it is too large, correct measured values cannot be obtained due to the influence of suction due to negative pressure. Therefore, it is necessary to determine an appropriate ventilation flow rate in advance, but it is not always easy to determine this because it depends on the size and shape of the container.
【０００８】上記の微細気象学的方法のうちで、渦相関
法は、フラックスの定義そのものに基づいた測定方法で
あり、かつガス交換面を攪乱しないため、原理的には長
期に渡って正しい測定値を求めることができる。Among the above micrometeorological methods, the eddy correlation method is a measurement method based on the definition of flux itself and does not disturb the gas exchange surface, so that in principle it is a correct measurement over a long period of time. The value can be calculated.
【０００９】しかし、風速とガス濃度との変動成分を測
定する必要があるため、非常に応答の早い特殊な風速計
とガス濃度計とを必要とする。また、ある程度広い面積
を要するため、ポット植え植物や個葉のガス交換には適
用できない。However, since it is necessary to measure the fluctuation components of the wind speed and the gas concentration, a special anemometer and a gas concentration meter which respond very quickly are required. In addition, since it requires a large area to some extent, it cannot be applied to gas exchange of pot plants and individual leaves.
【００１０】微細気象学的方法にうちで、傾度法は、風
速の垂直分布から大気の拡散抵抗を求め、これと２高度
間のガス濃度差とからガスフラックスを求めるものであ
る。しかし、この方法は、上記の渦相関法よりも更に広
い面積を要するとともに、気温の影響を考えた風速分布
を求める必要があり、このため大がかりな測定とならざ
るを得ない。また、風速傾度が小さい時には誤差が大き
くなる。拡散抵抗を熱収支から求める方法もあるが、気
温、湿度の他に正味放射量の測定も必要となるため、さ
らに大がかりで、複雑な測定となる。Among the micrometeorological methods, the gradient method obtains the diffusion resistance of the atmosphere from the vertical distribution of the wind speed, and obtains the gas flux from this and the gas concentration difference between two altitudes. However, this method requires a larger area than the above-mentioned eddy correlation method, and it is necessary to obtain the wind velocity distribution in consideration of the influence of the air temperature. Further, when the wind speed gradient is small, the error becomes large. There is also a method to obtain the diffusion resistance from the heat balance, but it requires a measurement of the net radiation amount in addition to the temperature and humidity, so it is a larger and more complicated measurement.
【００１１】[0011]
【発明が解決しようとする課題】以上のように、上記の
各方法では、簡単な装置で長期にわたって連続的にガス
フラックスを正確に測定することが困難であった。近年
では、地球温暖化問題等を背景として、世界各地でガス
フラックスの測定を正確に行う必要が生じており、多数
の地点で簡便かつ正確なガスフラックスを測定できる方
法及び装置が要望されている。As described above, in each of the above methods, it is difficult to accurately measure the gas flux continuously for a long period with a simple device. In recent years, against the background of global warming problems and the like, it has become necessary to accurately measure gas fluxes around the world, and there is a demand for a method and apparatus that can measure gas fluxes easily and accurately at many points. .
【００１２】本発明は、上記従来の課題に鑑みなされた
ものであり、その目的は、周囲環境の変化に影響されに
くく、簡易かつ正確にガスフラックスを測定できるガス
フラックス測定方法及び装置を提供することにある。The present invention has been made in view of the above-mentioned conventional problems, and an object thereof is to provide a gas flux measuring method and device which are not easily affected by changes in the surrounding environment and which can measure gas flux easily and accurately. Especially.
【００１３】[0013]
【課題を解決するための手段】上記目的を達成するため
に、本発明に係るガスフラックス測定方法は、被測定ガ
スを拡散抵抗が既知で形状一定の拡散媒体に通過させ、
前記拡散媒体の入口側ガス濃度、出口側ガス濃度、及
び、前記拡散媒体の拡散抵抗を用いて前記被測定ガスの
ガスフラックスを求めることを特徴とする。In order to achieve the above object, a gas flux measuring method according to the present invention is characterized in that a gas to be measured is passed through a diffusion medium having a known diffusion resistance and a constant shape,
It is characterized in that the gas flux of the gas to be measured is obtained by using the gas concentration on the inlet side of the diffusion medium, the gas concentration on the outlet side, and the diffusion resistance of the diffusion medium.
【００１４】また、本発明に係るガスフラックス測定装
置は、ガス入口開口とガス出口開口とを有し、被測定ガ
スを内部空洞に流通させるチェンバーと、前記チェンバ
ーにおける前記ガス入口開口とガス出口開口との間のガ
ス流路を塞いで設けられ、拡散抵抗が既知で形状一定の
拡散媒体と、前記拡散媒体の入口側と出口側とのガス濃
度差を求めるために設置される少なくとも１つのガス濃
度センサと、を含むことを特徴とする。Further, the gas flux measuring apparatus according to the present invention has a chamber having a gas inlet opening and a gas outlet opening, which allows the gas to be measured to flow into the internal cavity, and the gas inlet opening and the gas outlet opening in the chamber. And a diffusion medium having a known shape and a constant diffusion resistance, and at least one gas installed to determine the gas concentration difference between the inlet side and the outlet side of the diffusion medium. And a density sensor.
【００１５】[0015]
【作用】本発明に係るガスフラックス測定方法によれ
ば、被測定ガスを拡散媒体に通過させ、その状態で、入
口側と出口側のガス濃度差が測定される。なお、出口側
ガス濃度が大気中の一般値を用いることができる場合に
は、出口側ガス濃度の測定を省略することもできる。入
口側が大気開放されている場合も同様であり、その場合
には、入口側ガス濃度の測定を省略できる。いずれにし
ても、入口側ガス濃度と出口側ガス濃度との差であるガ
ス濃度差が求められ、そのガス濃度差と拡散媒体の拡散
抵抗とから、ガスフラックスが演算される。According to the gas flux measuring method of the present invention, the gas to be measured is passed through the diffusion medium, and the gas concentration difference between the inlet side and the outlet side is measured in this state. In addition, when the gas concentration on the outlet side can use a general value in the atmosphere, the measurement of the gas concentration on the outlet side can be omitted. The same applies when the inlet side is open to the atmosphere, and in that case, the measurement of the inlet side gas concentration can be omitted. In any case, the gas concentration difference, which is the difference between the gas concentration on the inlet side and the gas concentration on the outlet side, is obtained, and the gas flux is calculated from the gas concentration difference and the diffusion resistance of the diffusion medium.
【００１６】本発明では、拡散抵抗が既知の拡散媒体を
利用して、ガスフラックスの測定が行われるので、拡散
媒体の拡散抵抗を逐次測定する必要はなく、簡便な測定
を実現できる。また、周囲環境の変化に影響されにくい
ので、ガスフラックスの測定を正確に行うことができ
る。In the present invention, since the gas flux is measured using a diffusion medium whose diffusion resistance is known, it is not necessary to successively measure the diffusion resistance of the diffusion medium, and simple measurement can be realized. Moreover, since it is less susceptible to changes in the surrounding environment, the gas flux can be measured accurately.
【００１７】本発明に係るガスフラックス測定装置によ
れば、チェンバーがガス発生面（又はガス吸収面）に設
置され、その面から放出されるガス又はその面で吸収さ
れるガスがチェンバー内に導入される。チェンバーのガ
ス入口開口と出口開口との間は拡散媒体で塞がれている
ため、入口開口から流入したガスは必ず拡散媒体を通過
して出口開口に達することになる。ここで、拡散媒体
は、従来の傾度法とは異なり、拡散抵抗が既知の物質で
構成されている。このため、入口側ガス濃度と出口側ガ
ス濃度とのガス濃度差がわかれば、それと拡散抵抗から
ガスフラックスを演算することができる。According to the gas flux measuring apparatus of the present invention, the chamber is installed on the gas generating surface (or the gas absorbing surface), and the gas released from the surface or the gas absorbed by the surface is introduced into the chamber. To be done. Since the space between the gas inlet opening and the outlet opening of the chamber is blocked by the diffusion medium, the gas flowing from the inlet opening always passes through the diffusion medium and reaches the outlet opening. Here, unlike the conventional gradient method, the diffusion medium is made of a material having a known diffusion resistance. Therefore, if the gas concentration difference between the gas concentration on the inlet side and the gas concentration on the outlet side is known, the gas flux can be calculated from it and the diffusion resistance.
【００１８】[0018]
【実施例】図１には、本発明の原理が示されており、同
図において、（Ａ）は本発明に係るガスフラックス測定
の原理図であり、（Ｂ）は（Ａ）に示す測定系を電気回
路として置き換えた等価回路図である。FIG. 1 shows the principle of the present invention. In FIG. 1, (A) is a principle diagram of gas flux measurement according to the present invention, and (B) is the measurement shown in (A). It is the equivalent circuit diagram which replaced the system as an electric circuit.
【００１９】図１（Ａ）において、このガスフラックス
測定装置１２は、例えば、土壌１０の土壌面１０Ａに載
置されて土壌から出る二酸化炭素ガスの放出量を測定す
るための装置である。装置１２は、ガスが導入されるチ
ェンバー１４と、その内部に設置された拡散抵抗が既知
の拡散媒体１６と、で構成される。In FIG. 1A, the gas flux measuring device 12 is, for example, a device placed on the soil surface 10A of the soil 10 to measure the amount of carbon dioxide gas emitted from the soil. The device 12 is composed of a chamber 14 into which a gas is introduced, and a diffusion medium 16 having a known diffusion resistance installed inside the chamber 14.
【００２０】土壌面１０Ａから放出された二酸化炭素ガ
スは、チェンバー１４のガス入口開口内に導入され、チ
ェンバー内部を通過してガス出口開口から大気中へ放出
されるが、その間に拡散媒体を通過することになる。す
なわち、本発明は、拡散媒体１６の入口側ガス濃度と出
口側ガス濃度の差であるガス濃度差と、拡散媒体１６の
拡散抵抗と、を利用して、ガスフラックスに演算により
求めるものである。The carbon dioxide gas released from the soil surface 10A is introduced into the gas inlet opening of the chamber 14, passes through the inside of the chamber and is released into the atmosphere from the gas outlet opening, while passing through the diffusion medium. Will be done. That is, according to the present invention, the gas flux is calculated by using the gas concentration difference which is the difference between the gas concentration on the inlet side and the gas concentration on the outlet side of the diffusion medium 16 and the diffusion resistance of the diffusion medium 16. .
【００２１】図１（Ｂ）の回路は、発明の理解を容易に
するために参考として示した図であって、フラックスを
電流とみなしたガスフラックス測定系の等価電気回路で
ある。土壌１０中の拡散抵抗が抵抗Ｒs に相当し、拡散
媒体１６の拡散抵抗が抵抗Ｒc に相当する。また、入口
側ガス濃度がＢ点の電位に相当し、出口側ガス濃度がＢ
点の電位に相当する。すなわち、入口側ガス濃度と出口
側ガス濃度の濃度差は、（Ｂ）に示すＡ点及びＢ点の間
の電位差に相当する。The circuit of FIG. 1B is a diagram shown as a reference for facilitating the understanding of the invention, and is an equivalent electric circuit of a gas flux measuring system in which the flux is regarded as a current. The diffusion resistance in the soil 10 corresponds to the resistance R s, and the diffusion resistance of the diffusion medium 16 corresponds to the resistance R c . Further, the gas concentration on the inlet side corresponds to the potential at point B, and the gas concentration on the outlet side is B
It corresponds to the potential of the point. That is, the concentration difference between the inlet side gas concentration and the outlet side gas concentration corresponds to the potential difference between points A and B shown in (B).
【００２２】（Ｂ）において、いま、回路を流れる電流
ｉは、オームの法則により次式で与えられる。ただし、
ＥB 及びＥA は、それぞれＢ点及びＡ点の電位である。In (B), the current i flowing through the circuit is given by the following equation according to Ohm's law. However,
E B and E A are the potentials at points B and A, respectively.
【００２３】ｉ＝（ＥB −ＥA ）／Ｒc これと同様に、拡散媒体中を流れる二酸化炭素のフラッ
クス密度Ｆは次式で与えられる。ただし、ＣB 及びＣA
は、それぞれＢ点及びＡ点の二酸化炭素の濃度であり、
Ｒc は拡散媒体の拡散抵抗値である。I = (E B −E A ) / R c Similarly, the flux density F of carbon dioxide flowing in the diffusion medium is given by the following equation. However, C B and C A
Are the concentrations of carbon dioxide at points B and A, respectively,
R c is the diffusion resistance value of the diffusion medium.
【００２４】Ｆ＝（ＣB −ＣA ）／Ｒc 回路中を流れる電流ｉは、回路中の全抵抗値Ｒall 、す
なわち、 Ｒall ＝Ｒs ＋Ｒc に反比例する。このため、回路中にＲc を加えることに
より、電流ｉが過少評価される可能性がある。しかし、 Ｒs ＞＞Ｒc なる条件においては、 Ｒs ／（Ｒs ＋Ｒc ） が１にほぼ等しくなるので、回路中にＲc を加えること
による電流ｉへの影響は実際上、無視し得る。すなわ
ち、回路中に直列に接続して仕事を行わせることによっ
て回路中に流れる電流を測定する電流計と同様の測定系
を構成できる。[0024] F = (C B -C A) / R c current i flowing through the circuit, the total resistance R all in the circuit, i.e., inversely proportional to R all = R s + R c . Therefore, the current i may be underestimated by adding R c in the circuit. However, under the condition of R s >> R c , R s / (R s + R c ) is almost equal to 1, so the effect of adding R c in the circuit on the current i is practically neglected. obtain. That is, it is possible to configure a measurement system similar to an ammeter that measures the current flowing in the circuit by connecting the circuits in series to perform work.
【００２５】一方、同様の理論により、 Ｒs ＞＞Ｒc なる条件を満たすように、拡散媒体の拡散抵抗値Ｒc を
求めておけば、二酸化炭素フラックスに影響を与えるこ
となく、その大きさを求めることができる。On the other hand, if the diffusion resistance value R c of the diffusion medium is obtained so as to satisfy the condition of R s >> R c according to the same theory, the size of the diffusion resistance value R c is not affected and the carbon dioxide flux is not affected. Can be asked.
【００２６】また、チェンバー内Ｂ点における二酸化炭
素濃度ＣB は、フラックスが一定であるならば一定濃度
を保ち、経時的な単調増加又は単調減少はしないため、
長期間に渡って安定した測定が可能である。Further, since the carbon dioxide concentration C B is in the point B chamber, which if flux is constant maintaining a constant concentration, are not over time monotonically increasing or decreasing,
Stable measurement is possible over a long period of time.
【００２７】図２には、本発明に係るガスフラックス測
定装置の好適な実施例が示され、図２（Ａ）は装置１２
の上面図で、図２（Ｂ）は装置１２の断面図である。FIG. 2 shows a preferred embodiment of the gas flux measuring device according to the present invention, and FIG.
2B is a cross-sectional view of the device 12. FIG.
【００２８】同図において、チェンバー１４は、この実
施例において、プラスチック材料で構成されて内部が空
洞の円筒型をなしている。その一方側（図において下
方）は入口開口であり、その他方側（図において上方）
は出口開口である。なお、チェンバー１４の形状は、例
えば矩形であってもよい。In the figure, the chamber 14 in this embodiment is made of a plastic material and has a hollow cylindrical shape. One side (lower side in the figure) is the inlet opening, and the other side (upper side in the figure)
Is the outlet opening. The shape of the chamber 14 may be rectangular, for example.
【００２９】チェンバー１４内部には、入口開口と出口
開口の間のガス通路を塞ぐように、拡散抵抗が既知で一
定形状が維持される拡散媒体１６が均一な厚みをもって
配置されている。本実施例において、この拡散媒体１６
は、直径０．４ｍｍのガラスビーズを堆積させて構成さ
れている。このガラスビーズ層を形成するために、チェ
ンバー１４内には、金網２８が水平に張られている。本
実施例において、拡散媒体１６の入口側面１６Ａと出口
側面１６Ｂとの間の距離、すなわち拡散媒体の厚さは
３．３ｃｍである。なお、図２において、Ｌ１は１５６
ｍｍであり、Ｌ２は３０ｍｍであり、Ｌ３は７５ｍｍで
あり、Ｌ４は３５ｍｍである。これらの各寸法は一例で
あって、他の寸法を採用できる。Inside the chamber 14, a diffusion medium 16 having a known diffusion resistance and a constant shape is arranged with a uniform thickness so as to block the gas passage between the inlet opening and the outlet opening. In the present embodiment, this diffusion medium 16
Is formed by depositing glass beads having a diameter of 0.4 mm. In order to form this glass bead layer, a wire net 28 is horizontally stretched in the chamber 14. In this embodiment, the distance between the inlet side surface 16A and the outlet side surface 16B of the diffusion medium 16, that is, the thickness of the diffusion medium is 3.3 cm. In FIG. 2, L1 is 156.
mm, L2 is 30 mm, L3 is 75 mm, and L4 is 35 mm. Each of these dimensions is an example, and other dimensions can be adopted.
【００３０】拡散媒体１６としては、例えば多孔質材等
を用いることができる。また、液体を利用することもで
きるが、下面側を被測定ガスを透過させる半透膜等で構
成する必要がある。また、これと同様に、２つの半透膜
等で拡散媒体としての気体を封入することもできる。As the diffusion medium 16, for example, a porous material or the like can be used. Further, although a liquid can be used, it is necessary to form the lower surface side with a semipermeable membrane or the like that allows the gas to be measured to pass therethrough. Further, similarly to this, the gas as the diffusion medium can be enclosed by two semipermeable membranes or the like.
【００３１】いずれにしても、拡散媒体の全体形状は、
拡散抵抗の変動を防止するために、一定であることが必
要である。また、拡散媒体は、拡散抵抗が周囲環境によ
ってあまり影響を受けないことが望ましく、その意味
で、固体状の拡散媒体を利用することが望ましい。In any case, the overall shape of the diffusion medium is
It must be constant to prevent variations in diffusion resistance. Further, it is desirable that the diffusion resistance of the diffusion medium is not so affected by the surrounding environment, and in that sense, it is desirable to use a solid diffusion medium.
【００３２】図２において、チェンバー１４内には、ス
テー２６が横渡しされており、そのステー２６によっ
て、センサユニット２４が固定されている。このセンサ
ユニットは、隔膜２０とこの隔膜２０及び保護管で外部
とへだてられた電解溶液並びにそれに浸されたガラス電
極とで構成され、拡散媒体１６の入口側ガスが隔膜２０
を介してガラス電極に達し、そこでガス濃度が測定され
る。なお、被測定ガスの種類に応じたガス濃度センサが
利用される。In FIG. 2, a stay 26 is laterally provided in the chamber 14, and the sensor unit 24 is fixed by the stay 26. This sensor unit is composed of a diaphragm 20, an electrolytic solution that is pushed out to the outside by the diaphragm 20 and a protective tube, and a glass electrode immersed in the electrolytic solution. The gas on the inlet side of the diffusion medium 16 is separated by the diaphragm 20.
Is reached via a glass electrode where the gas concentration is measured. A gas concentration sensor corresponding to the type of gas to be measured is used.
【００３３】本実施例において、拡散媒体１６の出口側
ガス濃度として、大気中における当該ガスのガス濃度が
便宜上用いられ、後述のようにガス濃度差が演算され
る。しかし、図２に破線で示すように、出口側ガス濃度
測定用のガス濃度センサ２２を設け、入口側ガス濃度測
定と同時進行で出口側ガス濃度を測定すれば、より正確
にガスフラックスを求めることができる。In this embodiment, the gas concentration of the gas in the atmosphere is used for convenience as the gas concentration on the outlet side of the diffusion medium 16, and the gas concentration difference is calculated as described later. However, if the gas concentration sensor 22 for measuring the gas concentration on the outlet side is provided and the gas concentration on the outlet side is measured simultaneously with the measurement of the gas concentration on the inlet side as shown by the broken line in FIG. 2, the gas flux can be obtained more accurately. be able to.
【００３４】本実施例では、大気へのガス拡散を自然に
行わせるために、チェンバー１４における拡散媒体出口
側の壁の高さＨを数ｍｍとしているが、大気の流れ（横
風）が強いようであれば、壁の高さを大きくすることも
できる。また、チェンバー１４における拡散媒体出口側
の壁の高さＨは、大気の影響等に応じて調整できるよう
に構成してもよい。In this embodiment, the height H of the wall of the chamber 14 on the outlet side of the diffusion medium is set to several mm in order to naturally diffuse the gas into the atmosphere, but the flow of the atmosphere (crosswind) is strong. If so, the height of the wall can be increased. Further, the height H of the wall on the outlet side of the diffusion medium in the chamber 14 may be configured to be adjustable according to the influence of the atmosphere and the like.
【００３５】図３には、上記のガスフラックス測定装置
１２を用いたガスフラックス測定システムの一例が示さ
れている。このシステムを用いて、土壌から放出される
二酸化炭素のガスフラックスを測定する場合について説
明する。FIG. 3 shows an example of a gas flux measuring system using the gas flux measuring device 12 described above. The case of measuring the gas flux of carbon dioxide released from soil using this system will be described.
【００３６】まず、チェンバー１４の下端が土壌内へ数
ｃｍ差し込まれる。すると、土壌からの二酸化炭素ガス
がチェンバー１４内へ導入される。チェンバー１４内に
導入された二酸化炭素ガスは、拡散媒体１６を拡散し、
次第に拡散媒体１６の出口側に達することになり、一定
時間（例えば、数分間）の経過により、拡散媒体の入口
側ガス濃度と出口側ガス濃度が定常状態になる。その時
点で、入口側の二酸化炭素濃度が読み取られ、濃度差演
算装置３０は、入口側の二酸化炭素濃度から予め設定さ
れた大気中の二酸化炭素濃度α（例えば、３３０ｐｐ
ｍ）を減算し、濃度差を求める。ここで、濃度差は例え
ば数１００〜１０００ｐｐｍ程度となる。ガスフラック
ス演算装置３２は、その濃度差とメモリ３４に記憶され
た拡散媒体の拡散抵抗値とを利用して、土壌からの二酸
化炭素のガスフラックスを演算する。そして、その値が
表示器３６に表示される。First, the lower end of the chamber 14 is inserted into the soil by several cm. Then, carbon dioxide gas from the soil is introduced into the chamber 14. The carbon dioxide gas introduced into the chamber 14 diffuses through the diffusion medium 16,
It gradually reaches the outlet side of the diffusion medium 16, and after a certain period of time (for example, several minutes), the inlet side gas concentration and the outlet side gas concentration of the diffusion medium become steady. At that point, the carbon dioxide concentration on the inlet side is read, and the concentration difference calculation device 30 determines the carbon dioxide concentration α in the atmosphere set in advance from the carbon dioxide concentration on the inlet side (for example, 330 pp).
m) is subtracted to obtain the density difference. Here, the difference in concentration is, for example, about several hundreds to 1000 ppm. The gas flux calculation device 32 calculates the gas flux of carbon dioxide from the soil using the concentration difference and the diffusion resistance value of the diffusion medium stored in the memory 34. Then, the value is displayed on the display 36.
【００３７】本実施例の装置によれば、ガスが大気へ常
時放出されるので、例えば、土壌内の微生物の活動等に
影響を与えることはない。よって、本実施例の装置は、
長期間に渡って連続的にガスフラックスを測定する場合
に有効である。なお、拡散媒体の厚さは、装置の応答速
度に影響を及ぼすものであるため、より薄い拡散媒体と
すれば、それだけ応答性をよくできる。According to the apparatus of this embodiment, the gas is always released to the atmosphere, so that it does not affect, for example, the activity of microorganisms in the soil. Therefore, the device of this embodiment is
This is effective when continuously measuring the gas flux over a long period of time. Since the thickness of the diffusion medium affects the response speed of the device, the thinner the diffusion medium, the better the response.
【００３８】[0038]
【発明の効果】以上説明したように、本発明によれば、
拡散抵抗が既知の拡散媒体にフラックスを導入すること
により、フラックスの測定毎に煩雑な拡散抵抗の決定を
行う必要がなくなり、濃度差測定のみの簡便な測定を行
うことができる。As described above, according to the present invention,
By introducing the flux into a diffusion medium having a known diffusion resistance, it is not necessary to make a complicated determination of the diffusion resistance each time the flux is measured, and it is possible to perform a simple measurement only by measuring the concentration difference.
【００３９】また、拡散媒体の拡散抵抗を測定対象のそ
れよりも予め十分に小さくしておけば、放出されるガス
フラックスを過小評価することなく正確に測定できる。If the diffusion resistance of the diffusion medium is made sufficiently smaller than that of the object to be measured, the released gas flux can be accurately measured without being underestimated.
【００４０】さらに、ガスが拡散媒体を通して、常時、
チェンバー外へ自然条件下と同様に輸送されているの
で、チェンバー内濃度の極端な上昇（下降）に伴うソー
ス強度の変化を回避することができる。Further, the gas is constantly passed through the diffusion medium,
Since it is transported to the outside of the chamber under the same conditions as under natural conditions, it is possible to avoid a change in the source intensity due to an extreme rise (fall) in the concentration inside the chamber.
【図１】本発明の原理を示す原理説明図である。FIG. 1 is a principle explanatory view showing the principle of the present invention.
【図２】本発明に係るガスフラックス測定装置を示す図
である。FIG. 2 is a diagram showing a gas flux measuring device according to the present invention.
【図３】ガスフラックス測定システムの構成を示すブロ
ック図である。FIG. 3 is a block diagram showing a configuration of a gas flux measurement system.
１０ 土壌 １２ ガスフラックス測定装置 １４ チェンバー １６ 拡散媒体 10 Soil 12 Gas Flux Measuring Device 14 Chamber 16 Diffusion Medium
Claims (2)
の拡散媒体に通過させ、前記拡散媒体の入口側ガス濃
度、出口側ガス濃度、及び、前記拡散媒体の拡散抵抗を
用いて前記被測定ガスのガスフラックスを求めることを
特徴とするガスフラックス測定方法。1. A gas to be measured is passed through a diffusion medium having a known diffusion resistance and a constant shape, and the gas concentration is measured by using the gas concentration on the inlet side of the diffusion medium, the gas concentration on the outlet side, and the diffusion resistance of the diffusion medium. A gas flux measuring method, characterized in that a gas flux of a measurement gas is obtained.
被測定ガスを内部空洞に流通させるチェンバーと、 前記チェンバー内において前記ガス入口開口とガス出口
開口との間のガス流路を塞いで設けられ、拡散抵抗が既
知で形状一定の拡散媒体と、 前記拡散媒体の入口側と出口側とのガス濃度差を求める
ために設置される少なくとも１つのガス濃度センサと、 を含むことを特徴とするガスフラックス測定装置。2. A gas inlet opening and a gas outlet opening are provided,
A chamber that allows the gas to be measured to flow into the internal cavity, a diffusion medium that is provided in the chamber so as to close the gas flow path between the gas inlet opening and the gas outlet opening, and has a known diffusion resistance and a constant shape, A gas flux measuring device, comprising: at least one gas concentration sensor installed to determine a gas concentration difference between an inlet side and an outlet side of the diffusion medium.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12216294A JP2754161B2 (en) | 1994-06-03 | 1994-06-03 | Gas flux measuring method and apparatus |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12216294A JP2754161B2 (en) | 1994-06-03 | 1994-06-03 | Gas flux measuring method and apparatus |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH07333129A true JPH07333129A (en) | 1995-12-22 |
| JP2754161B2 JP2754161B2 (en) | 1998-05-20 |
Family
ID=14829127
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP12216294A Expired - Lifetime JP2754161B2 (en) | 1994-06-03 | 1994-06-03 | Gas flux measuring method and apparatus |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2754161B2 (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008203124A (en) * | 2007-02-21 | 2008-09-04 | Hitachi Kyowa Engineering Co Ltd | Apparatus and method for monitoring carbon dioxide leakage and method for fixing carbon dioxide in ground |
| WO2010069030A1 (en) | 2008-12-15 | 2010-06-24 | St. Francis Xavier University | Method of measuring the flux of a soil gas |
| JP2010204119A (en) * | 2010-06-07 | 2010-09-16 | Hitachi Ltd | Sample preparing device |
| US20110068940A1 (en) * | 2009-09-21 | 2011-03-24 | Korea Institute Of Geoscience And Mineral Resources (Kigam) | Apparatus for detecting carbon dioxide concentration in unsaturated zone, carbon dioxide concentration monitoring system, and carbon dioxide concentration monitoring method |
| US20130335728A1 (en) * | 2012-06-14 | 2013-12-19 | Gi-Tak CHAE | System and method for monitoring unsaturated zone gas and near-surface atmosphere in real time by using isotope analyzer |
| JP2015200525A (en) * | 2014-04-04 | 2015-11-12 | 国立大学法人九州大学 | Gas monitor device |
| CN105974086A (en) * | 2016-04-29 | 2016-09-28 | 衡阳师范学院 | Standard device and method for adjusting carbon dioxide flux and leakage and back-diffusion coefficients |
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1994
- 1994-06-03 JP JP12216294A patent/JP2754161B2/en not_active Expired - Lifetime
Cited By (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008203124A (en) * | 2007-02-21 | 2008-09-04 | Hitachi Kyowa Engineering Co Ltd | Apparatus and method for monitoring carbon dioxide leakage and method for fixing carbon dioxide in ground |
| EP2376873A4 (en) * | 2008-12-15 | 2014-03-19 | St Francis Xavier University | Method of measuring the flux of a soil gas |
| WO2010069030A1 (en) | 2008-12-15 | 2010-06-24 | St. Francis Xavier University | Method of measuring the flux of a soil gas |
| AU2008365226B2 (en) * | 2008-12-15 | 2015-05-28 | Eosense Inc. | Method of measuring the flux of a soil gas |
| EP2376873A1 (en) * | 2008-12-15 | 2011-10-19 | St. Francis Xavier University | Method of measuring the flux of a soil gas |
| US20110068940A1 (en) * | 2009-09-21 | 2011-03-24 | Korea Institute Of Geoscience And Mineral Resources (Kigam) | Apparatus for detecting carbon dioxide concentration in unsaturated zone, carbon dioxide concentration monitoring system, and carbon dioxide concentration monitoring method |
| US8466799B2 (en) * | 2009-09-21 | 2013-06-18 | Korea Institute Of Geoscience And Mineral Resources (Kigam) | Apparatus for detecting carbon dioxide concentration in unsaturated zone, and carbon dioxide concentration monitoring method |
| JP4612746B2 (en) * | 2010-06-07 | 2011-01-12 | 株式会社日立製作所 | Sample preparation equipment |
| JP2010204119A (en) * | 2010-06-07 | 2010-09-16 | Hitachi Ltd | Sample preparing device |
| US20130335728A1 (en) * | 2012-06-14 | 2013-12-19 | Gi-Tak CHAE | System and method for monitoring unsaturated zone gas and near-surface atmosphere in real time by using isotope analyzer |
| US8772720B2 (en) * | 2012-06-14 | 2014-07-08 | Korea Institute Of Geoscience And Mineral Resources | System and method for monitoring unsaturated zone gas and near-surface atmosphere in real time by using isotope analyzer |
| JP2015200525A (en) * | 2014-04-04 | 2015-11-12 | 国立大学法人九州大学 | Gas monitor device |
| CN105974086A (en) * | 2016-04-29 | 2016-09-28 | 衡阳师范学院 | Standard device and method for adjusting carbon dioxide flux and leakage and back-diffusion coefficients |
| CN105974086B (en) * | 2016-04-29 | 2018-01-16 | 衡阳师范学院 | Regulation of carbon dioxide flux and leakage and the standard set-up and method of back-diffusion coefficient |
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| JP2754161B2 (en) | 1998-05-20 |
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