1981-2020年毕节市大雾天气时空特征分析OA

This paper uses daily visibility data from 8 national meteorological stations in Bijie City from 1981 to 2020 to systematically analyze its spatio-temporal distribution characteristics and interannual variation laws.The results show that the number of heavy fog days in Bijie City shows obvious seasonal differences,with winter dominant and summer least;the overall interannual variation shows a downward trend and then upward trend,and suddenly changes in 2000.There are four main periods in the cycle evolution process:18 a,24 a,10 a and 3 a.The spatial distribution is extremely uneven,with Dafang Station having the largest number of annual fog days(173 days)and Hezhang Station having the lowest number(4.7 days),with an extreme difference of 36.8 times.EOF analysis showed that the first mode passed the North's test with variance contribution rate of 49.29%,and its spatial structure was highly consistent with the annual fog days,which could be used as the main type of fog spatial distribution in Bijie City.