Anomalous variation in summer tropical cyclone activity by preceding winter Aleutian low oscillation. (19th May 2017)

• Record Type: Journal Article
• Authors: Choi, Jae‐Won; Cha, Yumi
• Is Part Of: Atmospheric science letters. Volume 18:Number 6(2017)
• Page Start: 268
• Page End: 275
• Publication Date: 2017-05-19
• Subjects: tropical cyclone -- Aleutian low oscillation -- sea ice concentration; Atmospheric physics -- Periodicals; 551
• DOI: 10.1002/asl.752
• Languages: English
• ISSNs: 1530-261X

Abstract

Abstract: This research found a high‐positive correlation between Aleutian low oscillation during the winter (November–March) and tropical cyclone (TC) genesis frequency during the following summer (July–September) over a 26‐year period (1982–2007). In the years with high Aleutian low oscillation, a number of characteristics were analyzed. In the preceding winter, anomalous pressure patterns, such as south‐low and north‐high at the low level, formed as the center for the regions near 20°N in the western North Pacific. Sea ice concentration was less than the average around the Sea of Okhotsk and the Bering Sea, which weakened the Aleutian Low in this area. This anomalous pressure pattern continued until the following summer, and it reinforced the anomalous easterlies at the mid‐latitudes (20°–40°N) in East Asia and contributed to the high TC passage frequency in the East Asian continent. Abstract : Relationships between Aleutian low index for preceding November–March (NDJFM) and tropical cyclone genesis frequency in the western North Pacific for (a) July, (b) August, (c) September, and (d) all 3 months. The correlation coefficients are significant at the 95% confidence level.