关键词: 吉林省, 极端严寒事件, 时空特征, 评估方法

Abstract:

The bitter cold, an extreme weather event, is the main climate disaster in the winter in Jinlin Province and has deeply influenced on the production and people’s living. Analysis on spatial-temporal distribution and climate change pattern of the bitter cold , research on evaluation index of the bitter cold and effective pre-assessment before the event are of great significance on improving the emergency response and service capability.In this study, through using some index, such as grey correlation, climatic trend rate and Gumbel extreme value distribution, on the daily lowest temperature of 50 meteorological stations in Jilin Province from 1951 to 2013, the spatial-temporal distribution and climate change pattern of the bitter cold in Jinlin Province were analyzed. Then index on rating bitter cold process and on the return period of abnormal weather were proposed. Finally, the evaluation was conducted on the bitter cold process from 2011 to 2013.The results showed that in Jinlin Province, the bitter cold event mainly occurred in winter and reached a peak in about mid-January. This bitter cold event mostly happened in the central and southern regions and rarely occurred in other regions. The annual occurrence number of the bitter cold in the whole Jinlin Province showed the tendency of decline. However, the number of occurrences in central and western regions was increasing and the number in southeastern areas was decreasing. The occurrence number of the bitter cold in Jinlin Province had significantly periodic changes: the number was on the ‘large’ phase from 1951 to 1980 but it was on the ‘small’ phase from 1981 to 2012. The bitter cold process in Jinlin Province mainly occurred in January. Therefore, the defense against bitter cold should mainly been implemented in January and in the central and southern areas. Although it is in warming period now and the occurrence number of bitter cold is on the ‘small’ phase, bitter cold still abnormally occurred many times in some years. Therefore, attention should always be paid to the defense against the bitter cold. In this study, the methods that using index of orders, rating and the return period of abnormal weather to evaluate the process of the bitter cold are practical and feasible, which can meet the demands of meteorological services for timely and fast assessment.

Key words: Jilin Province, the extreme bitter cold event, spatial-temporal characteristics, assessment method