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

Journal of the Meteorological Society of Japan. Ser. II

Hartmut BORTH^1,15  Peter BECHTOLD¹³  Masaki SATOH^2,20  Hisashi NAKAMURA⁴  Kensuke NAKAJIMA^1,16  Yimin LIU^2,21  Andrea MOLOD²²  Akio KITOH^1,14  David L. WILLIAMSON^1,6  Michael BLACKBURN¹  Masahiro WATANABE^2,20  Kavirajan RAJENDRAN²  Yoshiyuki O. TAKAHASHI^1,7  Volkmar WIRTH^1,12  Wataru OHFUCHI^1,9  Masaki ISHIWATARI¹¹  Max J. SUAREZ²²  Helmut FRANK^1,18  Isaac M. HELD³  Ming ZHAO³  Myong-In LEE¹⁷  Hirofumi TOMITA^1,10  Masahide KIMOTO^2,20  John L. McGREGOR⁵  Rachel STRATTON^2,19  Yoshi-Yuki HAYASHI^1,7  Zaizhi WANG^1,8  Nils P. WEDI¹³ 

[1] National Centre for Atmospheric Science, University of Reading, Reading, UK;Center for Mathematical Modelling and Computer Simulation, National Aerospace Laboratories, Bangalore, India;Geophysical Fluid Dynamics Laboratory, Princeton University, Princeton, New Jersey, USA;Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan;CSIRO Marine and Atmospheric Research, Aspendale, Australia;National Center for Atmospheric Research, Boulder, Colorado, USA;Center for Planetary Science, Kobe, Japan;National Climate Center, China Meteorological Administration, Beijing, China;Japan Agency for Marine-Earth Science and Technology, Yokohama, Japan;Advanced Institute for Computational Science, RIKEN, Kobe, Japan;Graduate School of Science, Hokkaido University, Sapporo, Japan;Institute for Atmospheric Physics, University of Mainz, Mainz, Germany;European Centre for Medium-Range Weather Forecasts, Reading, Berkshire, UK;Meteorological Research Institute, Tsukuba, Japan;Theoretical Meteorology, University of Hamburg, Hamburg, Germany;Faculty of Sciences, Kyushu University, Fukuoka, Japan;Ulsan National Institute of Science and Technology, Ulsan, Korea;Research and Development, Deutscher Wetterdienst, Offenbach, Germany;Met Office, Exeter, UK;Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Japan;State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics, CAS, Beijing, China;Global Modeling and Assimilation Office, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA

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

DOI  :  10.2151/jmsj.2013-A03

学科分类：大气科学

来源: Meteorological Society of Japan

【 摘 要 】

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.

【 授权许可】

Unknown