Research on the effects of enso on frequency and intensity of cold air waves

Abstract

The influence of ENSO on cold air frequency and intensity was determined based on SSTA data in NINO 3, reanalyzed data and cold air waves affecting Vietnam in the period 1981 - 2019. The results show that the number of cold air waves tends to increase during the middle winter, and decrease in the early and late winter period. In the period 1993 - 2019, cold air waves of strong, medium, and weak intensity all tended to decrease and decrease the most for strong cold air waves. In addition, the number of cold air episodes is often higher than the average of many years during the non-ENSO period and lower than the average of many years in most of ENSO winter months. During the La Nina period, intense cold air waves were more frequent. However, the number of cold air episodes with weak and medium intensity prevailed during the El Nino and non-ENSO periods. Furthermore, ENSO has a very close relationship with the intensity of winter monsoons. In particular, during the second half of winter, the winter monsoon will weaken or intensify during El Nino/ La Nina period.