TY - JOUR
T1 - Atmospheric response to the North Pacific hotspot in idealized simulations
T2 - Application to explosive and binary cyclogenesis
AU - Yamamoto, Masaru
N1 - Funding Information:
The author thanks Dr Kuwano‐Yoshida and an anonymous reviewer for their careful reading of this manuscript and their many constructive comments. The WRF source code (version 3.9.1.1) was obtained from https://www2.mmm.ucar.edu/wrf/users/download/get_source.html . The National Center for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) Reanalysis 1 data were obtained from https://psl.noaa.gov/data/gridded/data.ncep.reanalysis.html . The Grid Analysis and Display System (GrADS, http://cola.gmu.edu/grads/) and the National Center for Atmospheric Research Command Language (NCL, https://www.ncl.ucar.edu/) were used for analysis and drawing figures. This study was supported by the Ocean and Atmosphere Research Project of the Research Institute for Applied Mechanics, Kyushu University, Japan (Refinement of Elementary Process Studies on the Ocean and Atmospheric Circulations in the East‐Asia Through Basin Scale, and its Application to Environmental Change) and grants‐in‐aid from the Ministry of Education, Culture, Sports, Science, and Technology (Japan)/Japan Society for the Promotion of Science (MEXT/JSPS KAKENHI; grant number JP19H05696).
Funding Information:
The author thanks Dr Kuwano-Yoshida and an anonymous reviewer for their careful reading of this manuscript and their many constructive comments. The WRF source code (version 3.9.1.1) was obtained from https://www2.mmm.ucar.edu/wrf/users/download/get_source.html. The National Center for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) Reanalysis 1 data were obtained from https://psl.noaa.gov/data/gridded/data.ncep.reanalysis.html. The Grid Analysis and Display System (GrADS, http://cola.gmu.edu/grads/) and the National Center for Atmospheric Research Command Language (NCL, https://www.ncl.ucar.edu/) were used for analysis and drawing figures. This study was supported by the Ocean and Atmosphere Research Project of the Research Institute for Applied Mechanics, Kyushu University, Japan (Refinement of Elementary Process Studies on the Ocean and Atmospheric Circulations in the East-Asia Through Basin Scale, and its Application to Environmental Change) and grants-in-aid from the Ministry of Education, Culture, Sports, Science, and Technology (Japan)/Japan Society for the Promotion of Science (MEXT/JSPS KAKENHI; grant number JP19H05696).
Publisher Copyright:
© 2021 The Author. Atmospheric Science Letters published by John Wiley & Sons Ltd on behalf of Royal Meteorological Society.
PY - 2021/10
Y1 - 2021/10
N2 - Marginal seas of the western North Pacific Ocean act as a hotspot in winter, warming the marine atmosphere. The atmospheric response to lower-level (below 700 hPa altitude) heating localized around this hotspot was studied using an idealized general circulation model with an assumed triangular hotspot. As simulated in previous studies, localized atmospheric heating over the mid-latitude hotspot enhances the westerly jet core, forming a stationary Rossby wave north of the core. This study found that the hotspot remotely influences the Rossby wave source (the sum of vortex stretching and vorticity advection caused by the divergent flow) and temperature deviations at upper levels (200–300 hPa). These results are qualitatively consistent with the winter climatology. The idealized experiment was applied to explosive and binary extratropical cyclones (pairs of surface cyclones located north and south of the main Japanese islands). The active area of transient eddies at lower levels splits into two in the hotspot, leading to regional explosive development and the formation of binary cyclones through an enhanced meridionally elongated trough. The hotspot is an essential factor driving the bifurcation of cyclone tracks into the southern and northern areas of Japan, leading to binary cyclones.
AB - Marginal seas of the western North Pacific Ocean act as a hotspot in winter, warming the marine atmosphere. The atmospheric response to lower-level (below 700 hPa altitude) heating localized around this hotspot was studied using an idealized general circulation model with an assumed triangular hotspot. As simulated in previous studies, localized atmospheric heating over the mid-latitude hotspot enhances the westerly jet core, forming a stationary Rossby wave north of the core. This study found that the hotspot remotely influences the Rossby wave source (the sum of vortex stretching and vorticity advection caused by the divergent flow) and temperature deviations at upper levels (200–300 hPa). These results are qualitatively consistent with the winter climatology. The idealized experiment was applied to explosive and binary extratropical cyclones (pairs of surface cyclones located north and south of the main Japanese islands). The active area of transient eddies at lower levels splits into two in the hotspot, leading to regional explosive development and the formation of binary cyclones through an enhanced meridionally elongated trough. The hotspot is an essential factor driving the bifurcation of cyclone tracks into the southern and northern areas of Japan, leading to binary cyclones.
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U2 - 10.1002/asl.1060
DO - 10.1002/asl.1060
M3 - Article
AN - SCOPUS:85109359109
VL - 22
JO - Atmospheric Science Letters
JF - Atmospheric Science Letters
SN - 1530-261X
IS - 10
M1 - e1060
ER -