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The East Asian Subtropical Jet Stream and Atlantic Tropical Cyclones
Journal article   Peer reviewed

The East Asian Subtropical Jet Stream and Atlantic Tropical Cyclones

Wei Zhang, Gabriele Villarini and Gabriel A Vecchi
Geophysical research letters, Vol.47(15), e2020GL088851
08/16/2020
DOI: 10.1029/2020GL088851

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Abstract

Atlantic tropical cyclones (TCs) can cause significant societal and economic impacts, as 2019's Dorian serves to remind us of these storms' destructiveness. Decades of effort to understand and predict Atlantic TC activity have improved seasonal forecast skill, but large uncertainties still remain, in part due to an incomplete understanding of the drivers of TC variability. Here we identify an association between the East Asian Subtropical Jet Stream (EASJ) during July–October and the frequency of Atlantic TCs (wind speed ≥34 knot) and hurricanes (wind speed ≥64 knot) during August–November based on observations for 1980–2018. This strong association is tied to the impacts of EASJ on a stationary Rossby wave train emanating from East Asia and the tropical Pacific to the North Atlantic, leading to changes in vertical wind shear in the Atlantic Main Development Region (80–20°W, 10–20°N). Plain Language Summary Atlantic tropical cyclones (TCs) are responsible for significant societal and economic impacts in terms of fatalities and property damage, as 2017's Harvey, Irma, and Maria, 2018's Florence and Matthew, and 2019's Dorian serve to highlight. There are still large uncertainties in current seasonal predictions for Atlantic TCs, which partly arise from our incomplete understanding of the drivers of the variability and nature of such storms. Here we find an association between the East Asian Subtropical Jet Stream (EASJ) during July–October and the frequency of Atlantic TCs during August–November based on observations for 1980–2018, arising from the impacts of EASJ on the propagation of Rossby wave trains from East Asia to the North Atlantic, leading to changes in vertical wind shear over the Atlantic Main Development Region (MDR). Key Points We identify an association between the East Asian Subtropical Jet Stream and the frequency of Atlantic TCs and hurricanes This association is tied to the impacts of EASJ on a stationary Rossby wave train emanating from East Asia and the tropical Pacific The stationary Rossby wave train leads to changes in vertical wind shear in the Atlantic Main Development Region
Hurricanes Rossby wave East Asian Subtropical Jet Stream Atlantic

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