出现海市蜃楼的天气特征分析

Analysis of Weather Characteristics for the Mirage

根据1987年、2006年秦皇岛沿海出现的三次海市蜃楼景观资料,统计分析了海市蜃楼景象发生时、发生前的天气形势、地面气压场、单站部分气象要素特征、GPS水汽探测资料等。结果表明:海市蜃楼一般出现在高空槽后,强冷空气刚刚过后十分稳定的地面高压前部。沿海地区,当近地面风很弱,气温急剧下降、湿度明显减少,700hPa温度露点差T-Td≥6℃,饱和湿空气层处于不稳定状态向稳定干空气状态转化时,海市蜃楼景观出现的几率较大。

Three mirages which took place in 1987 and 2006 were selected and some meteorological elements during and before the mirage, such as weather situation, surface pressure field, water vapor remotely sensed by GPS and local meteorological factors were analyzed. The result shows that the mirage usually occurs in the rear of upper trough. In the meantime, it is in the front of surface high pressure as dry and cold air just passed by. In the coastal region, if there would be these circumstances, such as a light wind, sharp decrease of temperature , low humidity, and the dew point deference is not lower than 6℃ at 700hPa, the layer of humid saturated air is in the transient state from an unstable condition to a stable situation of dry air, the wonderful view of mirage would have a high probability to take place.