应用大气扩散模式进行区域稻田甲烷源强估算

Application of Atmospheric Diffusion Model on The Estimate of Methane Emission from Rice Fields

传统通量箱方法对区域稻田甲烷源强的估算具有很大不确定性 .本研究应用箱模式和 ATDL模式估算区域稻田甲烷排放率 .箱模式和 ATDL模式估算排放率分别为 :6月 1 3.2～ 30 .4mg· (m2 · h) - 1 和 6.1～ 8.5mg· (m2 · h) - 1 ,9月 1 0 .4～2 0 .0 mg· (m2 · h) - 1 和 5.5～ 9.3mg· (m2 · h) - 1 ;而传统通量箱方法估算排放率为 :6月 0 .3～ 1 4.3mg· (m2 · h) - 1 ,9月 0～0 .3mg· (m2 · h) - 1 .分析表明 ,北京地区水稻生长季的接地逆温等不利气象条件使箱模式应用的基本假设难以满足 ,使之得出偏高的估算结果 . ATDL模式能较好地适应这种不利气象条件 ,并在 6月得出了与通量观测结果相近的估算结果 ,而其 9月高于通量观测结果的估算 ,却可能证实了通量箱方法难以测得的干旱稻田土壤裂缝的甲烷排放 ,有待于进一步研究证实 .

A atmospheric diffusion model to estimate the methane emission from rice fields was established.It turned out that the unfavorable meteorological conditions caused an overestimate for box model(13 2～30 4mg·(m 2·h) -1 in June and 10 4～20 0mg·(m 2·h) -1 in September),but ATDL model handled the unfavorable meteorological condition and give reasonable results(6 1～8 5mg·(m 2·h) -1 )closed to the closed chamber measurement(0 3～14 3mg·(m 2·h) -1 )in June.The overestimate of ATDL(5 5～9 3mg·(m 2·h) -1 )compare to the closed chamber measurement (0～0 3mg·(m 2·h) -1 )in September probably proved the methane emission from ditches of dry rice fields in the autumn.