1. Joint influence of the North Atlantic sea surface temperature and the Barents sea-ice concentration on the dipole pattern of Eurasian surface air temperature in March.
- Author
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Yuan, Yuan, Li, Huixin, Sun, Bo, He, Shengping, Li, Fei, and Li, Hua
- Subjects
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OCEAN temperature , *ATMOSPHERIC temperature , *SURFACE temperature , *ROSSBY waves , *ATMOSPHERIC models , *SEA ice - Abstract
In recent decades, an increase in the frequency of extreme events in early spring across Eurasia has resulted in significant impacts on crop yields and socio-economic development. However, the variations of March surface air temperature (SAT) over Eurasia and mechanisms are still unclear. This study aims to investigate the dominant mode of the March surface air temperature (SAT) over Eurasia during 1979–2022, and its relationship with sea surface temperature (SST) and sea ice concentration (SIC). The results reveal the prevalence of a dipole mode of the Eurasian SAT anomalies (SATAs) in March characterized by positive SATAs in northern (50°N–80°N) Eurasia and negative ones in southern (10°N–45°N) region. Further analyses demonstrate that this dipole mode of Eurasian SATAs shows significant relationships with a positive phase of the North Atlantic tripole SST anomalies (NAT SSTAs), as well as with the decline of Barents Sea SIC anomalies (SICAs). Associated with the NAT SSTAs and the Barents Sea SICAs during March, two Rossby wave trains propagate towards Eurasia through different ways, one is propagating eastwards from the mid-latitude of the North Atlantic to Eurasia, and another one spreads from the polar region to Eurasia. Modulated by these two wave trains, anomalous near-surface southwesterly (northeasterly) wind induces more (less) warm air towards northern Eurasia, while more (less) cloud emerges in southern Eurasia and causes less (more) solar radiation reaching southern Eurasia, leading to the dipole mode of the Eurasian SATAs in March. These results are further confirmed by numerical experiments from the version 5 of the Community Atmosphere Model forced by the above mentioned SSTAs and SICAs. • The main mode of March surface air temperature (SAT) distribution in Eurasia displays a north-south dipole pattern. • Two wave trains generated from mid-latitude and polar region respectively are closely related to this dipole SAT pattern. • The anomalies of the North Atlantic SST and the Barents Sea SIC can excite different wave trains modulating the Eurasian SAT. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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