2016年冬季河南三次持续污染过程的环流及关键气象要素特征
Circulation and Key Meteorological Factors for the Three Consecutive Air Pollution Processes in Henan During the Winter of 2016
中文摘要：
2016年11月28日—2017年1月11日，河南省出现了3次持续多日的中度及其以上的污染天气过程，分别为2016年11月28日—2016年12月5日、2016年12月15日—21日、2016年12月28日—2017年1月11日，尤其最后一次，持续时间长达15 d。第二次污染过程的后4 d，严重污染自北向南发展到全省。为了今后对持续污染天气的预报有所参考，对3次污染过程的气象要素演变及高空地面形势进行详尽分析，总结具有预报意义的天气学特征：当昼夜温差下降到4~6 ℃、温度露点差下降到0~5 ℃、风力约为2 m·s-1、气压变幅＜5 hPa时，可能会产生严重污染天气；污染期间，500 hPa高度正距平达5 dagpm以上，海平面为负距平或与常年同期相当，逐日高空环流显示，河南境内多短波槽活动或长期受偏西到西南气流影响，地面一般为均压场或鞍型场，气压梯度小，风力弱，当高低空在此形势配置下时，均有利污染天气的出现或加重；当925 hPa与1000 hPa的风切＜1.5 m·s-1，近地层湍流扩散弱，大气维持静稳状态，有利污染天气的发生发展；L波段探空显示，当200 m以下有逆温，100 m以下风速＜3 m·s-1，贴地层相对湿度在50%左右时，有可能出现重污染天气；在污染持续期间若出现小雨量级降水时，污染会有所减弱，但不会彻底清除；当高空转为较强西北气流或地面有强冷空气南下时，即气压梯度显著增加、风力明显加大，污染天气将彻底结束。
中文关键词：
持续污染，形势场特点，气象要素演变，L波段探空数据特征
KeyWords：
consecutive pollution, characteristics of the situation field, evolution of meteorological element, L-band sounding data feature
Abstract：
Three air pollution events happened from November 28, 2016 to January 11, 2017 in Henan Province. They occurred during November 28- December 5, 2016, December 15-21, 2016, and December 28, 2016-January 11, 2017 respectively. Each pollution event lasted several days, especially 15 days for the last one, with magnitude of moderate or above. Four days after the second air pollution process, serious pollution was spread from the north to the south covering the whole province. For enabling better forecast of consecutive air pollution event in the future, this study analyzed the evolution of meteorological elements and the situation of the upper ground surface of the three pollution processes in detail. Weather features with predictive significance were summarized. Serious pollution weather may be triggered in case the temperature difference between day and night drops to 4～6℃, dew point temperature drops to 0-5℃, the wind is about 2 m·s-1, and pressure amplitude is less than 5 hPa. During the pollution period, there were more short-wave trough activities in Henan. The ground was generally equalized or saddle-shaped probably because of the west-to-southwest airstream in the long-term. Air pollution is prone to occur when the pressure gradient was small, and the wind force was weak. As indicated by the L-band sounding data, heavy pollution may occur when there is temperature inversion below 200 m, the wind speed below 100m is less than 3 m·s-1, and the relative humidity of the surface layer is about 50%. The pollution will be weakened but not completely removed if there is light rainfall. When the sky turns into a stronger northwest airstream or the ground has strong cold air south (i.e., the pressure gradient force increases and the wind force obviously increases), the polluted weather will be completely disappeared.