熱収支フラックス比法による気体フラックスの推定  [in Japanese] Estimation of Gas Fluxes Using the Energy Balance Flux Ratio Method  [in Japanese]

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Abstract

熱収支フラックス比法を用いて農地からのCO<sub>2</sub>およびCH<sub>4</sub>フラックスなどを精確に推定するために,まず,この方法の変数である2高度間の測定温度差と測定混合比差を誤差伝播の法則を使って補正する方法を示した.次に,補正温度差と補正混合比差が比較的大きいデータから得られる乱流拡散係数と渦相関法で測定した摩擦速度との関係を得,これから得られる乱流拡散係数を用いて気体フラックスを推定する方法を示した.この推定法の適用性を検討するために,光量子変換効率(光量子1molあたりの植物体の炭素含量増加量)を用いて算定した純光合成量と,熱収支フラックス比法によるCO<sub>2</sub>フラックスを基礎にして推定した純光合成量とを比較検討した.両者は,比例係数が0.95,相関係数が0.97と,きわめて良好に一致した.以上ことから,熱収支フラックス比法によって気体フラックスが良好に推定できると考えられる.

To estimate CO<sub>2</sub> and CH<sub>4</sub> fluxes from an agricultural land accurately using the energy balance flux ratio method, first, the temperature difference and the mixing ratio difference between two heights, which are variables in the method, were corrected with the law of propagation of error. Next, the relationship between friction velocity and turbulent diffusion coefficient was obtained using data with relatively larger corrected temperature and mixing ratio differences, and fluxes were estimated using the turbulent diffusion coefficient calculated from the relationship. To verify the applicability of the method, the quantities of net photosynthesis calculated with estimated CO<sub>2</sub> fluxes were compared with those calculated using the photon conversion efficiency (the increment of carbon content in plant per 1mol of photon). Both quantities coincided satisfactorily with 0.95 of proportional coefficient and 0.97 of correlation coefficient. In conclusion, gas fluxes from an agricultural land could be estimated satisfactorily using the energy balance flux ratio method if the gas concentration could be measured accurately.

Journal

  • Transactions of The Japanese Society of Irrigation, Drainage and Rural Engineering

    Transactions of The Japanese Society of Irrigation, Drainage and Rural Engineering 80(2), 151-158, 2012

    The Japanese Society of Irrigation, Drainage and Rural Engineering

Codes

  • NII Article ID (NAID)
    130004555188
  • NII NACSIS-CAT ID (NCID)
    AA12240517
  • Text Lang
    JPN
  • ISSN
    1882-2789
  • NDL Article ID
    023761624
  • NDL Call No.
    Z18-365
  • Data Source
    NDL  J-STAGE 
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