Abstract:

The frequency of winter low-temperature events in Guangxi has obvious interannual and interdecadal variation characteristics from 1951 to 2020.In the early 1960s, it experiences an obvious mutation from less to more, and in the mid-1980s, it experiences a change from more to less.The period with a high frequency of low-temperature occurs from the middle of 1960s to the end of 1980s, and become less from the 1990s to the beginning of the 21st century.However, there are extreme years with unusually high frequency (such as 2008 and 2011) after the 2000s, which makes the frequency of low-temperature events show an upward trend.The frequency of low temperature in Guangxi has an interannual variation cycle of 2-5 years and an interdecadal cycle of about 10 years.Before 1990, the variation of low-temperature frequency is caused by the superposition of the above two main cycles, and then the signal of the cycle weakens, until 2005, the 2-5 years of the cycle appears again.The analysis results of the variation of winter low-temperature frequency in Guangxi and the East Asian monsoon and the Atlantic sea surface temperature show that the strong East Asian winter monsoon is conducive to the increase of low-temperature frequency in Guangxi.The Atlantic sea surface temperature in the west of Europe is abnormally low, and the circulation anomaly caused by the interaction of air and sea is the possible reason for the significant low temperature and the abnormal increase of low-temperature frequency in Guangxi.

Key words: Interannual variation, Interdecadal variation, East Asian winter monsoon, Sea surface temperature anomaly