Japan Geoscience Union Meeting 2016

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International Session (Oral)

Symbol A (Atmospheric and Hydrospheric Sciences) » A-AS Atmospheric Sciences, Meteorology & Atmospheric Environment

[A-AS02] High performance computing of next generation weather, climate, and environmental sciences using K

Sun. May 22, 2016 1:45 PM - 3:15 PM 302 (3F)

Convener:*Masaki Satoh(Atmosphere and Ocean Research Institute, The University of Tokyo), Masahide Kimoto(Atmosphere and Ocean Research Institute, The University of Tokyo), Kazuo Saito(Forecast Research Department, Meteorological Research Institute), Hiromu Seko(Meteorological Research Institute), Takemasa Miyoshi(RIKEN Advanced Institute for Computational Science), Tetsuro Tamura(Tokyo Institute of Technology), Hiroshi Niino(Dynamic Marine Meteorology Group, Department of Physical Oceanography, Atmosphere and Ocean Research Institute,The University of Tokyo), Masayuki Takigawa(Japan Agency for Marine-Earth Science and Technology), Hirofumi Tomita(AICS, RIKEN), Chihiro Kodama(Japan Agency for Marine-Earth Science and Technology), Chair:Chihiro Kodama(Japan Agency for Marine-Earth Science and Technology)

2:45 PM - 3:00 PM

[AAS02-05] Vertical grid spacing necessary for simulating tropical cirrus clouds

*TATSUYA SEIKI1, Chihiro Kodama1, Masaki Satoh2, Tempei Hashino3, Yuichiro Hagihara4, Hajime Okamoto3 (1.Japan Agency for Marine-Earth Science and Technology, 2.Atmosphere and Ocean Research Institute, The University of Tokyo, 3.Research Institute for Applied Mechanics, Kyushu University, 4.Earth Observation Research Center, Japan Aerospace Exploration Agency)

Keywords:General Circulation Model, Climate, Cirrus

The distribution of simulated cirrus clouds over the tropics is affected by the particular model’s vertical grid spacing. To examine this effect, we use a high-resolution atmospheric general circulation model NICAM with 28-km and 14-km horizontal meshes. We show that a vertical grid spacing of at least 400 m is necessary to resolve the bulk structure of cirrus clouds. As one reduces the vertical grid spacing below about 1000 m, the visible cirrus cloud fraction decreases, the cloud thins (optically and geometrically), the cloud-top height lowers, and consequently, the OLR increases. These effects are stronger over the tropics. When using a vertical grid spacing of 400 m or less, the vertical profiles of effective radii and ice water content converge toward measurements (CloudSat satellite and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation).