Coastal Downwelling Intensifies Landfalling Hurricanes

Gramer, Lewis J.; Zhang, Jun A.; Alaka, Ghassan J.; Hazelton, Andrew; Gopalakrishnan, Sundararaman

doi:10.1029/2021gl096630

Cited by 14 publications

(4 citation statements)

References 57 publications

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“…Note that a smaller TC distance to land means the TC location is closer to a landmass. Such observation is consistent with a recent study that suggests that coastal downwelling due to TC passage may influence TC intensification (Gramer et al 2022).…”

Section: Trends and Shifts In Tc Activity In Wnpsupporting

confidence: 93%

Decreasing Quiescence of Tropical Cyclones in the Western North Pacific

Duran

Basconcillo

2023

SOLA

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Due to less tropical cyclone (TC) occurrences, the climatology of the quiescent TC season (i.e., March-April-May, MAM) in the Western North Pacific (WNP) is less understood when compared to the more active season (i.e., June-November). Here we show observational evidence of significantly decreasing TC quiescence during MAM that can be attributed to more Central Pacific El Niño events from 2002 to 2022. A Central Pacific El Niño is related to an asymmetric sea surface temperature (SST) pattern where warm (cool) SST anomalies are concentrated in the central (western) Pacific, which consequently contributes to the overall decrease in TC quiescence in MAM. Such anomalous SST pattern prompts the Western North Pacific Subtropical High to expand westward, creating a conducive large-scale environment for TC development and allowing TCs to move closer to the landmass, which ultimately leads to an increasing cost of TC-associated damages during the quiescent season. Our study provides new insights into the decreasing TC quiescence and TC climatology in the WNP during MAM, which is ultimately expected to contribute to disaster risk reduction in the region.

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Section: Trends and Shifts In Tc Activity In Wnpsupporting

confidence: 93%

Decreasing Quiescence of Tropical Cyclones in the Western North Pacific

Duran

Basconcillo

2023

SOLA

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“…Taken together, these results imply that the nearshore regions of the SEC have become more favorable for producing increased TC‐induced SST cooling, consistent with the changes in the upper‐ocean over that region. It has to be noted that U.S land falling TCs could initiate upwelling/downwelling along continental shelf regions in response to the direction in which they approach the land (Gramer et al., 2022). However, the mechanism explained here is in the context of long‐term changes in the atmospheric circulation and its effect on pre‐storm oceanic conditions, which is different from the short‐term changes in oceanic environment (upwelling/downwelling) that may occur during a storm.…”

Section: Resultsmentioning

confidence: 99%

Observed Increase in Tropical Cyclone‐Induced Sea Surface Cooling Near the U.S. Southeast Coast

John,

Balaguru,

Leung

et al. 2024

Geophysical Research Letters

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Tropical cyclones (TCs) induce substantial upper‐ocean mixing and upwelling, leading to sea surface cooling. In this study, we explore changes in TC‐induced cold wakes along the United States (U.S.) Southeast and Gulf Coasts during 1982–2020. Our study shows a significant increase in TC‐induced sea surface temperature (SST) cooling of about 0.20°C near the U.S. Southeast Coast over this period. However, for the U.S. Gulf Coast, trends in TC‐induced SST cooling are insignificant. Analysis of the large‐scale oceanic environments indicate that the increasing TC‐induced cold wakes near the Southeast coast have been predominantly caused by the cooling of subsurface waters in that region. This upper‐ocean change is attributed to the enhancement of surface pressure gradient across land‐sea boundary and the associated increase in alongshore winds over there. Further analysis with climate models reveals the important role of anthropogenic forcings in driving these changes in the atmospheric circulation response along the U.S. Southeast Coast.

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“…The primary controls of the intensity of mature TCs are vertical wind shear, dry air intrusion, and the fluxes of enthalpy and momentum between the surface ocean and atmosphere (Emanuel, 1986). Recent studies have shown that the upper ocean can evolve rapidly beneath TCs (Dzwonkowski et al, 2021;Glenn et al, 2016;Gramer et al, 2022;Miles et al, 2017;Seroka et al, 2016Seroka et al, , 2017 and feedback on storm intensity.…”

mentioning

confidence: 99%

Ocean mixing during Hurricane Ida (2021): The impact of a freshwater barrier layer

Miles

Coakley

Rudzin

et al. 2023

Preprint

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Tropical cyclones are one of the costliest and deadliest natural disasters globally, and impacts are currently expected to worsen with a changing climate. Hurricane Ida (2021) made landfall as a category 4 storm on the US gulf coast after intensifying over a Loop Current eddy and a freshwater barrier layer that extended from the coast to the open ocean waters off the continental shelf. An autonomous underwater glider sampled this ocean feature ahead of Ida. We use this data with 1-D shear driven mixed layer models to investigate the sensitivity of the upper ocean mixing to a barrier layer during Ida’s intensification period. We show that the freshwater barrier layer inhibited cooling by as much as 56% and resulted in increased enthalpy flux to the atmosphere by >20% as the storm made landfall. This highlights the utility of sustained observations to support coupled ocean and atmosphere hurricane forecasts.

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Coastal Downwelling Intensifies Landfalling Hurricanes

Cited by 14 publications

References 57 publications

Decreasing Quiescence of Tropical Cyclones in the Western North Pacific

Decreasing Quiescence of Tropical Cyclones in the Western North Pacific

Observed Increase in Tropical Cyclone‐Induced Sea Surface Cooling Near the U.S. Southeast Coast

Ocean mixing during Hurricane Ida (2021): The impact of a freshwater barrier layer

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