Monthly Fine Forecast Indexes of High Temperature Weather in Xi'an Area
Based on high temperature weather observation data in Xi'an urban and six counties from 1987 to 2016,the spatial and temporal features of high temperature weather with temperature above 35 ℃,37 ℃ and 40 ℃ occurring in Xi'an area were analyzed by using synoptic principle and statistical method.It showed that high temperature days increased in recent 30 years,concretely speaking,for temperature above 35 ℃,37 ℃ and 40 ℃,the increasing rate of high temperature days were 3.3 days per 10 years,3 days per 10 years and 0.2 day per 10 years,respectively.As for monthly variation,high temperature days with temperature above 35 ℃ and 37 ℃ were most in July,while high temperature days with temperature above 40 ℃ were most in June.According to different atmospheric circulation on 500 hPa,the circulations influencing high temperature weather in Xi'an were classified into 3 types,including northwest airstream type,subtropical anticyclone type (subtropical anticyclone impact type and subtropical anticyclone control type) and continental warm anticyclone type.Furthermore,the monthly fine forecast indexes of high temperature weather with temperature above 35 ℃,37 ℃ and 40 ℃ were summarized by analyzing the position and temperature range of warm air in upper and lower level,sea-level pressure,the 24 h surface allobaric field,temperature and cloud cover,EC numerical weather prediction product and temperature on 850 hPa and surface in five reference stations,etc,these forecast factors all occurred at 08:00 BST on the previous day of high temperature.
high temperature weathermonthly fine forecast indexesXi'an area
NETL
NSTL
万方数据
维普
