中国平流层CH_4的分布特征和季节变化

Distribution Features and Seasonal Variations of Stratospheric CH_4 over China

利用UARS卫星上HALOE试验的1992—2003年CH4资料,分析了中国平流层的CH4混合比分布特征,并对CH4混合比在不同纬度上的季节变化作了详细分析。结果表明,中国平流层CH4混合比随着高度逐渐减小,在经向上有较大差异,总是南边大于北边,而各个纬度带上的分布则较均匀。分析结果还表明,中国平流层CH4混合比在DJF的季节距平与MAM有相反的符号,而且中心位置基本吻合。此外,季节变率最大的是MAM—DJF,而不是JJA—DJF。并且在平流层低层的夏半年有明显的高值带,这可能与上升运动和辐散辐合作用有关。

CH4 data throughout 1992 to 2003 from HALOE experiment on UARS are used to analyze the features of distribution and seasonal variations of stratospheric CH4 mixing ratio over China. The results show that the stratospheric CH4 mixing ratio over China decrease with height, and there are more larger meridional differences than zonal differences and highter CH4 concentration to the south than that to the north. Usually, CH4 concentration varies a little with longitudes. Moreover, the seasonal departures of stratospheric CH4 mixing ratio over china are reverse signs between DJF and MAM, and their centers are in most agreement. There are the largest seasonal variability between MAM and DJF. Other that, there are high value region of CH4 mixing ratio during summer at lower stratosphere, and most probably, upward motion and divergence play important role on the high CH4 concentration in half-summer.