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Influence of the late-winter North Atlantic tripole sea surface temperature anomalies on spring land surface temperature in mid–high latitudes of Western Eurasia

Authors :
Yidi Song
Haishan Chen
Source :
Journal of Climate. :1-43
Publication Year :
2023
Publisher :
American Meteorological Society, 2023.

Abstract

The spring land surface temperature (LST) over Western Eurasia, which is critical for ensuring food security, shows a clear interannual variability. Based on reanalysis data and numerical simulations, we investigated the potential influencing factors and the related mechanisms of spring LST variability in mid–high latitudes of Western Eurasia (MHWEA). The results show that the North Atlantic tripole sea surface temperature anomalies (SSTAs) in February, which persist into spring, can significantly affect the spring LST variability over MHWEA. Analyses indicate that the positive phase of the North Atlantic tripole SSTA pattern tends to increase the meridional SST gradient between positive SSTAs over the mid-latitude North Atlantic and negative SSTAs over the south of Greenland, which strengthens the low-level atmospheric baroclinicity and thus induces more active transient eddy activities. Correspondingly, a Rossby wave train triggered by the eddy-mediated processes originates from the North Atlantic and propagates downstream, thereby causing anomalous anticyclonic circulation over MHWEA. Meanwhile, the westerly anomalies over the subpolar North Atlantic accelerate the polar front jet and provide a favorable thermodynamical condition for the tropospheric warming over the Barents–Kara Seas by bringing warm and moist oceanic air. The polar warming tends to weaken the poleward temperature gradient at mid–high latitudes and then decelerate the Eurasian mid-latitude westerlies, thus dynamically contributing to the circulation changes that can affect spring LST over MHWEA. Model results suggest that the link can be generally reproduced. Therefore, the late-winter North Atlantic tripole SST may act as a precursor for the prediction of spring LST over Western Eurasia.

Subjects

Subjects :
Atmospheric Science

Details

ISSN :
15200442 and 08948755
Database :
OpenAIRE
Journal :
Journal of Climate
Accession number :
edsair.doi...........3af99dc0487bc1bdd9c17b0473c30319