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The Last Glacial Maximum (LGM) at 21,000 years before present is a marked climate event with thick ice sheets over North America and Europe and associated sea level drop of about 120 m. We used the most updated coupled climate model results to analyze the climate change over Korea for the LGM. Eight coupled models (CCSM, CNRM, COSMOS, FGOALS, IPSL, MIROC, MPI, and MRI) were used to analyze the LGM climate. With LGM boundary conditions, surface air temperature decreases almost everywhere in all seasons with the largest cooling in winter and least cooling in summer. Overall, in the LGM, the multi-model annual-mean cooling over Korea is 5.85 C°, which is consistent with proxy evidence using pollen reconstructions. Associated with the surface cooling, precipitation decreases in general, with the largest reduction in winter by 56%, but in summer precipitation increases by 12% in the LGM over Korea. Overall, precipitation decreases by about 14% in the LGM over Korea. The surface cooling tends to increase surface pressure almost everywhere over Asia. The sea level pressure increase is especially larger in high latitudes and this leads to the easterly wind anomaly in northern part of Korea. On the other hand, in South Korea, the increase in surface pressure leads to the westerly wind anomaly. The increase in surface pressure associated with surface cooling leads to the anticlockwise wind anomalies in the LGM over Korea. [ABSTRACT FROM AUTHOR]

Understanding the relationship between Arctic Sea Ice Concentration (SIC) and Indian Summer Monsoon Rainfall (ISMR) is crucial for analysing regional climate change. Present study investigates this connection using satellite observations and simulations from Coupled Model Intercomparison Project Phase 5 (CMIP5) and CMIP6 coupled climate models, focusing on external forcing from 1979 to 2021. Rotated Empirical Orthogonal Function (REOF) analysis identified the dominant mode (PC1) of ISMR, explaining 31.7% of the variance with significant regional variability. Singular Value Decomposition (SVD) analysis revealed a maximum covariance of 41.1% during spring between Arctic SIC observations and ISMR. Leading SVD correlations for the multi-model ensemble mean (MMEM) simulations of spring Arctic SIC were 30.6% (CMIP5) and 42.8% (CMIP6). Our results demonstrate a significant correlation between ISMR PC1 and observed Arctic spring SIC (r = −0.25, p < 0.10), particularly in the Central Arctic (r = 0.51, p < 0.01) and the Barents-Kara Sea (r = −0.39, p < 0.01). During the High Sea Ice Years (HSYs) in the Central Arctic, distinct pressure pattern centres developed extending from western Europe to the western Pacific Ocean and were linked to the circumglobal teleconnection (CGT) influence circulation. Anomalous highs over western central Asia and a strengthened easterly jet enhance rainfall in northwestern and peninsular India. Conversely, weakened jets and high-pressure systems during Low Sea Ice Years (LSYs) hinder the monsoon. This highlights the influence of upper atmospheric Rossby waves on circulation patterns. Similarly, during LSYs in the Barents-Kara Sea, the North Atlantic-Eurasia teleconnection wave train pattern and ridge formation over northwestern Europe affect the Indian monsoon's onset. North European geopotential height anomalies contribute to formation of these ridges and troughs, impacting wind patterns and thermodynamic instability, ultimately influencing rainfall distribution. This comprehensive study underscores the far-reaching impacts of seasonal Arctic changes on the ISMR, emphasising the critical role of climate teleconnections between Arctic SIC and the Indian monsoon. Our results suggest an improved understanding of regional Arctic SIC dynamics is vital for accurate ISMR predictions using future climate models. • Satellite observations and MMEM (CMIP5 and CMIP6) datasets show spring Arctic SIC is significantly impacts ISMR. • Statistical analysis shows ISMR strongly correlates with Central Arctic and Barents-Kara Sea SIC. • HSYs in the Central Arctic lead to distinct pressure patterns from western Europe to western Pacific Ocean, influencing ISMR. • North Atlantic-Eurasia teleconnection and ridge formation over NW Europe during Barents-Kara Sea LSYs affect onset of ISMR. [ABSTRACT FROM AUTHOR]

In this study, we investigated the daily variability of PM 10 concentrations in January in Korea during the past 19 years (2001-2019), as well as the associated atmospheric circulation patterns. The daily PM 10 concentrations were classified into three cases: low (L; < 50 μg/m 3 ), high (H; 50-100 μg/m 3 ), and extremely high (EH; ≥ 100 μg/m 3 ). We found that the strength of the East Asian winter monsoon influenced the PM 10 variability in the L and H cases. However, the EH cases were strongly influenced by the rapid growth of barotropic warming (anticyclonic anomaly) over the eastern North Atlantic and Northern Europe (ENE), and the stationary Rossby waves grew rapidly over Eurasia within only four days. Analysis of the quasi-geostrophic geopotential tendency budget revealed that the anticyclonic anomaly over the ENE was enhanced by vorticity advection. Linear baroclinic model experiments confirmed that vorticity forcing over the ENE induces favorable atmospheric conditions for the occurrence of EH PM 10 events in East Asia. As a result, the PM 10 concentration sharply increased sharply by approximately three times over four days. This study suggests that understanding atmospheric teleconnections between the ENE and East Asia can effectively predict the occurrence of EH PM 10 events in Korea, helping to reduce the human health risks from atmospheric pollution., (Copyright © 2021 The Authors. Published by Elsevier Ltd.. All rights reserved.)