稻田CH_4排放的农业气象数值模拟研究

NUMERICAL SIMULATION OF CH_4 EMISSION FROM RICE PADDY FIELDS DURING RECENT 50 YEARS

在美国DNDC模式基础上 ,综合气象学、农业气象学及生态学最新研究进展 ,将作物生长、碳氮循环及CH4排放有机耦合 ,建立了一个CH4排放数值模式 ,模式通过了相关显著性检验。利用模式重点分析了气象因子对稻田CH4排放的影响状况 ,数值分析表明 ,当仅考虑气象条件影响时 :( 1 )不同地区不同生长季节的CH4排放量均与相应生长期的平均气温成正相关关系 ;( 2 )功率谱分析表明稻田CH4排放存在 4～ 5年周期变化 ,与相应生长季节的平均温度年际变化规律相一致 ;( 3)CH4排放量年际之间变化趋势与生长季平均气温变化趋势基本一致。利用数值计算结果 ,给出了杭州及昌德地区早稻、晚稻CH4简易统计模式 。

Based on the DNDC model of American, a numerical model for simulating CH 4 emis sion from rice paddy fields is established. Validation of the model with the obs erved data shows that the mean relative error is about 15%. The simulation analy sis results show that the CH 4 emission is interrelated well with average tem perature during rice growth periods. Analysis of CH 4 emission and meteorologic al factors by using power spectrum indicates that the change of CH 4 emissions has 4-5 year cycles, which is the same as that of temperature. Simple statistic al models are given based on the results of the numerical model, which can be applied conveniently to estimate and monitor CH 4 emissions in the rice paddy f ields.