太湖流域近地表主要温室气体本底浓度特征

Background Density Characteristic of the Main Greenhouse Gas Near-surface in Tai Lake Basin

根据2003年1月—2005年6月太湖流域近地表大气中主要温室气体CO2、CH4和N2O本底浓度的监测资料,研究了该流域近地表大气主要温室气体浓度的变化特征。结果表明,在观测时段内,该流域近地表大气CO2浓度呈上升趋势;CH4浓度呈逐年递减趋势;N2O浓度呈先减后增趋势。3种气体主要与人类活动、工农业生产和交通运输业发展有关,CO2浓度的季节变化明显,冬春季高,夏秋季低,最高值在12月,最低值在8月;CH4浓度由春至夏升高,由夏至秋至冬递减,最高值在7月,最低值在2月;N2O浓度没有明显的季节变化,它们主要受源汇强度变化影响。CO2浓度的日变化基本呈双峰态,是源汇强度变化和边界层稳定程度相互作用的原因,CH4浓度无明显日变化规律,N2O浓度日变化中的最高值总体呈现是夏、秋、春至冬逐渐延迟的状态。

According to the monitoring materials on background density near- surface of Tai Lake basin from January 2003 to June 2005, this article has studied the change characteristics of the main greenhouse gases like CO2, CH4 and N2O. The results have shown in the observation time, the average density of CO2 is with the trend of more and more high, the average density of CH4 is with decreasing year by year, the average density of N2O is with the tendency of first reducing and then increasing. The tendency of three kinds of gases was very close relation with the mankind activity, such as industry, agriculture and transportation. The change of CO2 density was obvious seasonal variation with high in winter and spring and low in summer and autumn, the maximum appeared in December and the minimum appeared in August. The CH4 density elevated from spring to summer and decreased from summer to winter, and the maximum data appeared in July, the minimum appeared in February. The change of N2O density was not obvious seasonal variation with have being influenced under the intensity variation of sources and sinks. As the daily change, the CO2 density was double - peak, the CH4 was no obvious rule, and the highest change data of N2O was from summer to the fall, and then to spring and winter.