摘要
利用2015年NCEP/NCAR再分析一日四时次资料和日资料,应用区域平均、热流量方程估算等方法对2015年12月29日北极爆发性增温的原因进行研究。结果表明,2015年12月29日北极出现爆发性增温,日增温幅度最高达到25°C以上。增温期间,受到强盛温带气旋系统和反气旋系统的共同作用,增温区域出现强盛的南风,风速最大值达到20 m s-1以上,位置不断北进达到北极点。强盛的南风为北极地区带来强盛的暖平流,同时暖湿空气进入北极后,增温区上空云量明显增加。12月28日至12月29日温度平流由冷平流转变为暖平流,暖平流的中心区域与温度爆发性增长的区域有很好的对应关系,暖平流是北极爆发性增温的重要原因。对于一直处于极夜的北极地区,由于云量的增加,大气顶向上长波辐射减少,加剧了温度的上升。温度平流增温贡献率为20.4%,垂直项的贡献率为-9.9%,非绝热作用贡献率为89.5%,温度平流和非绝热作用共同导致了本次北极地区的爆发性增温,非绝热作用是本次爆发性增温最重要的增温因素。
With 6-h and daily reanalysis data from NCEP/NCAR, we studied the mechanisms for the sudden Arctic warming on 29 December 2015. The signal area average method and heat flow equation for temperature estimation were used in this study. It revealed that there was a sudden warming in the Arctic on 29 December 2015 and the maximum temperature increase was over 25°C or more. There existed strong southerly winds with speeds larger than 20 m s-1 over the warming area during the same period, which was driven by the combined effects of a strong cyclone and anti-cyclone. The strong moist southerly winds brought warm temperature to the Arctic region and enhanced cloud cover over the sudden warming area.The temperature advection turned from cold pattern to warm pattern from 28 December to 29December,which corresponded to the rapid increase in temperature and indicated that warm temperature advection played a vital role in the sudden Arctic warming.The enhanced cloud cover led to deceases in the upward long-wave radiation flux in the dark night,contributing to the temperature rise.For the sudden warming,the contributions of temperature advection,vertical term,and non-adiabatic effect were 20.4%,-9.9%,and 89.5%,respectively.Therefore,the temperature advection and non-adiabatic effect were responsible for the sudden Arctic warming,and the non-adiabatic effect was a more important factor.
出处
《大气科学》
CSCD
北大核心
2017年第6期1343-1351,共9页
Chinese Journal of Atmospheric Sciences
基金
国家自然科学基金项目41675066
气象灾害教育部重点实验室(南京信息工程大学)开放课题KLME1401~~
关键词
北极爆发性增温
暖平流
非绝热作用
Arctic sudden warming, Warm temperature advection, Non-adiabatic effect
