云南大理洱海溶解氧日变化特征分析

利用大理国家气候观象台依托于JICA项目,在洱海湖中建立的自动观测系统2009年全年的观测资料,分析了溶解氧的日变化特征。结果表明:洱海湖中溶解氧表现为日出后最小、日落后最大的日变化特征。全年变化范围为2.31～7.98 mg/L,最大值出现在12月20:00时,而最小值出现在9月10:00时;较小时段出现在6-10月,各月月平均12月最大,9月最小,年较差为4.83 mg/L;四季中冬季偏大,夏季偏小,冬春季比夏秋季明显偏大。四季中各个典型日的日较差相对于各季的平均偏大,峰值、谷值出现时间大都偏晚。连阴雨出现后,由于受低温阴雨寡照的影响,洱海溶解氧偏高。

Diurnal Variation of Dissolved Oxygen in Erhai Lake of Dali

Based on the observational data in 2009 from a water surface observation system in Erhai lake developed in Dali national climatic observatory,diurnal variations of dissolved oxygen were analyzed.The results show that the average dissolved oxygen is high after sunrise and low after sunset,throughout a year ranged between 2.31 mg/L and 7.98 mg/L,the maximum is at 20:00 in December and minimum at 10:00 in September.The dissolved oxygen is lower than annual average from June to October in the year,the maximum of monthly mean is in December and the minimum is in September,the annual range is 4.83 mg/L,the highest is in winter,followed by spring,then autumn and summer.The diurnal range of the typical days for 4 seasons is bigger than the average of 4 seasons',and the maximum and minimum values of displaying time tend to be late mostly.The dissolved oxygen is very high because of low water temperature and little sunshine during heavy continuous autumn rainy days.