%0 Journal Article %A JING Fu-Xi %A DAN Yuan-Yuan %A BAI Hu-Zhi %T Climatic Characteristic of Thunderstorm W eather Variations in the Middle Part Of Gansu Province %D 2007 %R %J Journal of Arid Meteorology %P 53-57 %V 25 %N 1 %X

11he climatic variation feature of the first and tIIe last dates for thunderstorm occurring and thunderstorm days in tIIe middle part  of Gansu province was analyzed by using observations of4 stations in Baiyin from 1958 to 2005 based on statistics methods of linear tend-encv estimate and wavelet analysis.Results show that the first dates of tIIunderstorm presented a delay trend(2.7 d/10 a)in the north plain:the last dates were ahead(一2.6 d/lO a)in tIIe north plain and presented parabola change in tIIe soutII mountain area.The first date variation of thunderstorm in the north plain Was steadier than that in tIIe south mountain 81"PAl,whereas tIIe last date variation of thun -derstorm in the south mountain area was steadier than that in the north plain,an d the first date change Was steadier than that of the last date of thunderstorm.Th e corresponding threshold of5一da y average temperature Was 9℃ and ll℃ in tIIe north plain for the first and last dates.respectively,and 6℃ in the south mountain.Thunderstorm days were more in tIIe soutII and less in the north,the period of8—10 vears was remarkable before the middle of the 1980s and the general trend of thunderstorm days Was decreasing.

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