2012年北京市密云县年平均气温与常年同期持平,降水偏多,雨热同期,年日照时数低于常年同期,光照减少。年内出现局地性降雹情况及61 a一遇的特大暴雨,对密云县经济发展产生影响。2012年年度的冬小麦返青期延迟。2013年年度冬小麦有良好的底墒。夏玉米生长受到抑制,生长高度偏高,籽粒不饱满,产量因素较差。

The haze appeared frequently with city economic growth.And it had significant indication meaning.So the people had much attention to the haze.In the weather service,the haze was as an important work.But because the similarity between the mist and the haze,sometimes the observe made a mistake.The paper compared and discussed the cause of formation,feature and reciprocal transformation between the mist and the haze.The result supplied some reference to practical work.