Intensity change and zonal and meridional movements of the Aleutian Low and their associated broad-scale atmospheric-oceanic characteristics

• Published in: Atmospheric research 2023-12, Vol.296, p.107074, Article 107074
• Main Authors: Lin, Nan, Yang, Song, Ren, Qiaoling, Zhang, Tuantuan, Cheung, Ho-Nam
• Format: Article
• Language: English
• Subjects: Aleutian Low; ENSO; Intensity variation and zonal/meridional shifts; Interannual variability; Winter monsoon
• ISSN: 0169-8095; 1873-2895
• DOI: 10.1016/j.atmosres.2023.107074

The changes in the intensity and position of the Aleutian Low (AL) exert significant effects on the ocean-land-atmosphere interactive processes and climate over East Asia, the North Pacific, and North America. In this study, the interannual variations of the AL intensity, meridional shift, and zonal shift, as well as their associated dynamical processes are investigated. The results show that the intensity, meridional shift, and zonal shift of the AL are well characterized by the three leading EOF modes of sea level pressure over the North Pacific, and are strongly correlated with the Pacific-North American pattern, the West Pacific pattern, and the Tropical/Northern Hemisphere pattern, respectively. The intensity variation of the winter AL seems to be closely associated with the ENSO-related atmosphere-ocean processes in the previous autumn, whereas the meridional shift is not associated any significant signal in the previous months, signifying a relatively higher predictability of the former. Besides, the eastward and westward movements of the AL show asymmetric features, attributed possibly to their asymmetric relationships with ENSO. •The leading EOF modes over the North Pacific are applied to respectively define the intensity variation, meridional movement, and zonal movement of the Aleutian Low (AL), and understand the associated climate features.•The intensification of the AL exhibits a significant cyclonic anomaly over the central North Pacific from the proceeding autumn to the next spring, related probably to ENSO, while its meridional movement shows no obvious signals in spring and autumn.•The zonal shift of the AL is asymmetric. When moving eastward, the AL lasts from the previous autumn to the later spring, with a high-pressure anomaly over the southeast of the Hawaiian Islands in winter. However, no apparent feature can be found when the AL moves westward. This asymmetricity feature may be because the AL eastward shift receives a stronger tropical forcing than its westward movement.