TY - JOUR
T1 - Impacts of Extratropical Weather Perturbations on Tropical Cyclone Activity
T2 - Idealized Sensitivity Experiments With a Regional Atmospheric Model
AU - Zhang, Gan
AU - Knutson, Thomas R.
AU - Garner, Stephen T.
N1 - Funding Information:
1.gfdl.noaa.gov/users/Gan.Zhang/TC‐Extratropics/GFDL‐ZETAC G. Zhang is supported by Princeton University's Cooperative Institute for Modeling the Earth system, through the Predictability and Explaining Extremes Initiative. The NCEP‐NCAR reanalysis data are publicly available ( https://rda.ucar.edu/datasets/ds090.0/ ). The HURDAT is acquired from AOML/NOAA ( http://www.aoml.noaa.gov/hrd/hurdat/Data_Storm.html ). We thank Drs. Jan‐Huey Chen and Kun Gao for helpful comments. The model data used to generate the plots are available at GFDL data portal (ftp://data /).
Funding Information:
G. Zhang is supported by Princeton University's Cooperative Institute for Modeling the Earth system, through the Predictability and Explaining Extremes Initiative. The NCEP-NCAR reanalysis data are publicly available (https://rda.ucar.edu/datasets/ds090.0/). The HURDAT is acquired from AOML/NOAA (http://www.aoml.noaa.gov/hrd/hurdat/Data_Storm.html). We thank Drs. Jan-Huey Chen and Kun Gao for helpful comments. The model data used to generate the plots are available at GFDL data portal (ftp://data?1.gfdl.noaa.gov/users/Gan.Zhang/TC-Extratropics/GFDL-ZETAC/).
Publisher Copyright:
©2019. American Geophysical Union. All Rights Reserved.
PY - 2019/12/16
Y1 - 2019/12/16
N2 - Extratropical weather perturbations have been linked to Atlantic tropical cyclones (TCs) activity in observations. However, modeling studies of the extratropical impact are scarce and disagree about its importance and climate implications. Using a nonhydrostatic regional atmospheric model, we explore the extratropical impact by artificially suppressing extratropical weather perturbations at the tropical-extratropical interface. Our 22-year simulations of August–October suggest that the extratropical suppression adds ~3.7 Atlantic TCs per season on average, although the response varies among individual years. The TC response mainly appears within 30–40°N, where tropical cyclogenesis frequency quadruples compared to control simulations. This increased cyclogenesis, accompanied by a strong increase of midtropospheric relative humidity, arises as the perturbation suppression reduces the extratropical interference of TC development. The suppression of extratropical perturbations is highly idealized but may suggest mechanisms by which extratropical atmospheric variability potentially influences TC activity in past or future altered climate states.
AB - Extratropical weather perturbations have been linked to Atlantic tropical cyclones (TCs) activity in observations. However, modeling studies of the extratropical impact are scarce and disagree about its importance and climate implications. Using a nonhydrostatic regional atmospheric model, we explore the extratropical impact by artificially suppressing extratropical weather perturbations at the tropical-extratropical interface. Our 22-year simulations of August–October suggest that the extratropical suppression adds ~3.7 Atlantic TCs per season on average, although the response varies among individual years. The TC response mainly appears within 30–40°N, where tropical cyclogenesis frequency quadruples compared to control simulations. This increased cyclogenesis, accompanied by a strong increase of midtropospheric relative humidity, arises as the perturbation suppression reduces the extratropical interference of TC development. The suppression of extratropical perturbations is highly idealized but may suggest mechanisms by which extratropical atmospheric variability potentially influences TC activity in past or future altered climate states.
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U2 - 10.1029/2019GL085398
DO - 10.1029/2019GL085398
M3 - Article
AN - SCOPUS:85076860170
SN - 0094-8276
VL - 46
SP - 14052
EP - 14062
JO - Geophysical Research Letters
JF - Geophysical Research Letters
IS - 23
ER -