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| ENSO impact on the variability of wintertime synoptic-scale air temperature over China and possible mechanisms behind |
| Received:May 15, 2019 Revised:December 09, 2019 |
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| KeyWord:ENSO;Air temperature variability;Synoptic-scale;Siberian storm track |
| Author Name | Affiliation | E-mail | | REN Manlin | Key Laboratory of Meteorological Disaster of Ministry of Education，Joint International Research Laboratory of Climate and Environment Change，Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters，Nanjing University of Information Science & Technology，Nanjing 210044，China | | | ZHANG Wenjun | Key Laboratory of Meteorological Disaster of Ministry of Education，Joint International Research Laboratory of Climate and Environment Change，Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters，Nanjing University of Information Science & Technology，Nanjing 210044，China | zhangwj@nuist.edu.cn | | GENG Xin | Key Laboratory of Meteorological Disaster of Ministry of Education，Joint International Research Laboratory of Climate and Environment Change，Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters，Nanjing University of Information Science & Technology，Nanjing 210044，China | | | LIU Chao | Key Laboratory of Meteorological Disaster of Ministry of Education，Joint International Research Laboratory of Climate and Environment Change，Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters，Nanjing University of Information Science & Technology，Nanjing 210044，China | |
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| Abstract: |
| The present study investigates ENSO impact on the variability of wintertime synoptic-scale air temperature over China based on daily averaged air temperature data collected at 753 stations and compiled by the National Meteorological Information Center, the NOAA reconstructed monthly sea surface temperature and the NCEP/NCAR reanalysis data from 1960 to 2017. The results show that ENSO is significantly positively correlated with wintertime synoptic-scale air temperature variability in a large area of eastern China. The fluctuation of temperature and synoptic-scale air temperature variability are usually stronger than normal during El Niño winters. In contrast, the synoptic-scale air temperature variability is weakened during La Niña winters. Further research finds that during El Niño winters, the meridional temperature gradient in the middle and high latitudes of Eurasia strengthens, leading to enhanced local atmospheric baroclinicity according to the thermal wind relationship and thus further increasing storm activities in the Siberian region and synoptic-scale variation of atmospheric circulation in East Asia region. Correspondingly, the synoptic-scale air temperature variability enhances in most areas of China. Roughly opposite mechanisms apply during La Niña winters. |