The Aqua-Planet Experiment (APE): Response to Changed Meridional SST Profile

David L. WILLIAMSON; Michael BLACKBURN; Kensuke NAKAJIMA; Wataru OHFUCHI; Yoshiyuki O. TAKAHASHI; Yoshi-Yuki HAYASHI; Hisashi NAKAMURA; Masaki ISHIWATARI; John L. McGREGOR; Hartmut BORTH; Volkmar WIRTH; Helmut FRANK; Peter BECHTOLD; Nils P. WEDI; Hirofumi TOMITA; Masaki SATOH; Ming ZHAO; Isaac M. HELD; Max J. SUAREZ; Myong-In LEE; Masahiro WATANABE; Masahide KIMOTO; Yimin LIU; Zaizhi WANG; Andrea MOLOD; Kavirajan RAJENDRAN; Akio KITOH; Rachel STRATTON

doi:10.2151/jmsj.2013-A03

Articles

The Aqua-Planet Experiment (APE): Response to Changed Meridional SST Profile

David L. WILLIAMSON, Michael BLACKBURN, Kensuke NAKAJIMA, Wataru OHFUCHI, Yoshiyuki O. TAKAHASHI, Yoshi-Yuki HAYASHI, Hisashi NAKAMURA, Masaki ISHIWATARI, John L. McGREGOR, Hartmut BORTH, Volkmar WIRTH, Helmut FRANK, Peter BECHTOLD, Nils P. WEDI, Hirofumi TOMITA, Masaki SATOH, Ming ZHAO, Isaac M. HELD, Max J. SUAREZ, Myong-In LEE, Masahiro WATANABE, Masahide KIMOTO, Yimin LIU, Zaizhi WANG, Andrea MOLOD, Kavirajan RAJENDRAN, Akio KITOH, Rachel STRATTON

Author information

David L. WILLIAMSON
National Center for Atmospheric Research, Boulder, Colorado, USA
Michael BLACKBURN
National Centre for Atmospheric Science, University of Reading, Reading, UK
Kensuke NAKAJIMA
Faculty of Sciences, Kyushu University, Fukuoka, Japan
Wataru OHFUCHI
Japan Agency for Marine-Earth Science and Technology, Yokohama, Japan
Yoshiyuki O. TAKAHASHI
Center for Planetary Science, Kobe, Japan
Faculty of Science, Kobe University, Kobe, Japan
Yoshi-Yuki HAYASHI
Center for Planetary Science, Kobe, Japan
Faculty of Science, Kobe University, Kobe, Japan
Hisashi NAKAMURA
Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan
Masaki ISHIWATARI
Graduate School of Science, Hokkaido University, Sapporo, Japan
John L. McGREGOR
CSIRO Marine and Atmospheric Research, Aspendale, Australia
Hartmut BORTH
Theoretical Meteorology, University of Hamburg, Hamburg, Germany
Volkmar WIRTH
Institute for Atmospheric Physics, University of Mainz, Mainz, Germany
Helmut FRANK
Research and Development, Deutscher Wetterdienst, Offenbach, Germany
Peter BECHTOLD
European Centre for Medium-Range Weather Forecasts, Reading, Berkshire, UK
Nils P. WEDI
European Centre for Medium-Range Weather Forecasts, Reading, Berkshire, UK
Hirofumi TOMITA
Advanced Institute for Computational Science, RIKEN, Kobe, Japan
Masaki SATOH
Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Japan
Ming ZHAO
Geophysical Fluid Dynamics Laboratory, Princeton University, Princeton, New Jersey, USA
Isaac M. HELD
Geophysical Fluid Dynamics Laboratory, Princeton University, Princeton, New Jersey, USA
Max J. SUAREZ
Global Modeling and Assimilation Office, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
Myong-In LEE
Ulsan National Institute of Science and Technology, Ulsan, Korea
Masahiro WATANABE
Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Japan
Masahide KIMOTO
Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Japan
Yimin LIU
State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics, CAS, Beijing, China
Zaizhi WANG
National Climate Center, China Meteorological Administration, Beijing, China
Andrea MOLOD
Global Modeling and Assimilation Office, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
Kavirajan RAJENDRAN
Center for Mathematical Modelling and Computer Simulation, National Aerospace Laboratories, Bangalore, India
Akio KITOH
Meteorological Research Institute, Tsukuba, Japan
Rachel STRATTON
Met Office, Exeter, UK

Keywords: comparison of atmospheric general circulation models (GCMs), sea surface temperature profile, Hadley circulation, intertropical convergence zone (ITCZ), precipitation

JOURNAL FREE ACCESS
Supplementary material

2013 Volume 91A Pages 57-89

DOI https://doi.org/10.2151/jmsj.2013-A03

Details

Abstract

This paper explores the sensitivity of Atmospheric General Circulation Model (AGCM) simulations to changes in the meridional distribution of sea surface temperature (SST). The simulations are for an aqua-planet, a water covered Earth with no land, orography or sea-ice and with specified zonally symmetric SST. Simulations from 14 AGCMs developed for Numerical Weather Prediction and climate applications are compared. Four experiments are performed to study the sensitivity to the meridional SST profile. These profiles range from one in which the SST gradient continues to the equator to one which is flat approaching the equator, all with the same maximum SST at the equator.
The zonal mean circulation of all models shows strong sensitivity to latitudinal distribution of SST. The Hadley circulation weakens and shifts poleward as the SST profile flattens in the tropics. One question of interest is the formation of a double versus a single ITCZ. There is a large variation between models of the strength of the ITCZ and where in the SST experiment sequence they transition from a single to double ITCZ. The SST profiles are defined such that as the equatorial SST gradient flattens, the maximum gradient increases and moves poleward. This leads to a weakening of the mid-latitude jet accompanied by a poleward shift of the jet core. Also considered are tropical wave activity and tropical precipitation frequency distributions. The details of each vary greatly between models, both with a given SST and in the response to the change in SST.
One additional experiment is included to examine the sensitivity to an off-equatorial SST maximum. The upward branch of the Hadley circulation follows the SST maximum off the equator. The models that form a single precipitation maximum when the maximum SST is on the equator shift the precipitation maximum off equator and keep it centered over the SST maximum. Those that form a double with minimum on the equatorial maximum SST shift the double structure off the equator, keeping the minimum over the maximum SST. In both situations only modest changes appear in the shifted profile of zonal average precipitation. When the upward branch of the Hadley circulation moves into the hemisphere with SST maximum, the zonal average zonal, meridional and vertical winds all indicate that the Hadley cell in the other hemisphere dominates.

Corresponding author

Register with J-STAGE for free!