Variety Characteristic of Fogs on Hebei in Recent 40 Years

摘要

Weather data from 1960 to 1999 used to analyze the characteristics of spatial and temporal distribution of the fog in Hebei, changing rules of different time scales, variety trend and characteristics of visibility. The results showed that: there was a general upward trend of Hebei fog days, especially from the late 1980s, when Hebei went foggy; fog days mainly concentrated in winter, mostly in November and December; fogs of level 3 visibility were mostly often, and the reverse of level 1. generally speaking, the stations in foggy zone, fog had become a trend of a gradual increase hi level 1, while level 2 the opposite; in winter fog in foggy zone, generated after nightfall, dispersed around noon; continuous fog days generally appeared from November to February the next year. Fog in less fog zone lasted at a relatively short time, not more than 2-4 days; while in foggy zone lasted much longer, which may reach 5-11 days.