CAJ | 학술논문

利用1966—2011年西藏自治区那曲地区所辖7个气象站的雷暴天气历史观测资料，综合运用天气学及线性统计方法、小波分析方法，分析那曲地区雷暴日数的时间和空间分布规律及影响因素。结果表明：那曲地区的雷暴日数存在显著减少趋势，减少趋势达到0．01的显著性水平，变化倾向率为每10年减少5 d；那曲地区雷暴日数空间分布特征为北部多南部少，东部高山峡谷多于西部湖盆；雷暴日数高值出现在东北部，低值出现在东南部。季节分布为夏季最多，春、秋季相对较少，冬季很少出现雷暴；雷暴初日推迟，而雷暴终日提前，雷暴期有缩短趋势。多雷期、少雷期的差异主要表现在西太平洋副热带高压脊线西伸脊点的经度位置、巴尔克什湖东部至青藏高原处高压脊和高原短波槽的位置和强弱上。那曲地区5—9月雷暴日数存在5～10年、20年两种尺度的周期变化规律，从不同时间尺度周期的变化趋势可以看出那曲地区将逐渐进入多雷期。
이용1966—2011년서장자치구나곡지구소할7개기상참적뇌폭천기역사관측자료，종합운용천기학급선성통계방법、소파분석방법，분석나곡지구뇌폭일수적시간화공간분포규률급영향인소。결과표명：나곡지구적뇌폭일수존재현저감소추세，감소추세체도0．01적현저성수평，변화경향솔위매10년감소5 d；나곡지구뇌폭일수공간분포특정위북부다남부소，동부고산협곡다우서부호분；뇌폭일수고치출현재동북부，저치출현재동남부。계절분포위하계최다，춘、추계상대교소，동계흔소출현뇌폭；뇌폭초일추지，이뇌폭종일제전，뇌폭기유축단추세。다뢰기、소뢰기적차이주요표현재서태평양부열대고압척선서신척점적경도위치、파이극십호동부지청장고원처고압척화고원단파조적위치화강약상。나곡지구5—9월뇌폭일수존재5～10년、20년량충척도적주기변화규률，종불동시간척도주기적변화추세가이간출나곡지구장축점진입다뢰기。
Using synoptic meteorology,linear statistical methods and wavelet analysis,thunderstorm data from seven meteorological observatories in Nagqu Prefecture from 1966 to 2011 are analyzed to find the trend and space distribution of the number of thunderstorm days and influencing factors.A significant decreasing trend is found in the number of annual thunderstorm days,and the decreasing rate is around five days per decade.The cause for this trend might be that stronger latitudinal atmospheric circulation and weaker lon-gitudinal circulation in the context of global warming reduces the intensity and frequency of cold air,and the mechanical lifting of moist air,which is not conductive to the formation of thunder clouds.Spatially, there is a deceasing number of thunderstorm days from the north to the south,from high mountainous val-leys in the east to plains in the west with the highest number of thunderstorm days in the northeast and the lowest in the southeast.This feature is closely associated with differences in topography,thermal condi-tions,moisture conditions and climate across the prefecture.Due to high temperatures and strong convec-tive activities in summer,there are significantly more thunderstorm days in spring and fall,and there are less thunderstorm days in winter with cold drying weather and relatively stable atmospheric stratification. As the weather becomes drier in winter,thunderstorms start later and end earlier with a decreasing trend in the period of thunderstorm activity within a year.The inter-annual difference in the number of thunder-storm days mainly depends on the westward move of the subtropical high over the West Pacific Ocean,the position and strength of the ridge line between the east Lake Balkhash high and the Tibetan Plateau high, and the shortwave trough off the Tibetan Plateau.When the west Pacific subtropical high weakens or moves eastward,and the warm moist airflow is prevalent in Nagqu,the number of thunderstorm days is higher.When the west Pacific subtropical high strengthens or moves westward,and the northwest airflow is prevalent in Nagqu,the number of thunderstorm days is lower.Two variation periods of 5-10 years and 20 years are found in the number of mean annual thunderstorm days between May and September. These variations indicate that Nagqu Prefecture will experience a period of a higher number of thunder-storm days .