Abstract: Based on high-temperature days data(maximum temperature ≥38℃) from 17 meteorological stations in Shijiazhuang,the variation of high-temperature days in 5 representative stations was analyzed,by using linear regression,polynomial fitting curve,Mexican hat wavelet analysis and Mann-Kendall mutation test.The results showed that high-temperature days in mountain and hill region were higher than that in plain region.Linear increasing trend of high-temperature days was stronger in urban and southwest mountain,weaker in northwest mountain and southeast plain,but high-temperature days in northeastern plain showed a weak linear decreasing trend.High-temperature days increased significantly since the 21st century,but the beginning date of increasing in plain region was later than in mountain and hill region.Moreover,all stations with high-temperature days were high stage in less than 10-year cycle,but it was different in southeast plain region.The results indicated that foehn effect in special topography,the maintenance of warm air mass in low-altitude and the urbanization effect had strengthened high-temperature.

Key words: High-temperature days, High-temperature days, Variation characteristics, Foehn effect, Warm air mass, Urbanization effect