Abstract: Based on daily weather phenomenon, relative humidity and visibility data at 76 weather stations from 1961 to 2013, daily haze sequence was rebuilt in Hubei province, and a grade evaluation model for a large scale persistent haze event and corresponding indexes were built.Temporal and spatial characteristics of haze day and large scale consecutive haze events in Hubei province were also analyzed.The results show that there are a few differences between raw and corrected data for interdecadal variation of temporal and spatial distribution, while both trends are contrary.Interdecadal characteristics of haze day are significant in the recent 50 years in Hubei province according to sequence reconstruction of haze day.It is in a significant increasing trend after 2000, and haze day often occurs in winter.The large scale consecutive haze events mainly appear in 1970s and the early 21st century, especially in 2013.Higher frequency haze day is in the eastern region of northwestern Hubei province, and the north-central region of eastern Hubei province.According the results, the use of the LSCHI index to evaluate the large scale persistent haze period produces a better result.

Key words: Sequence reconstruction, Large scale persistent haze period, LSCHI index