The Impact of the Time Step on the Intensity of ITCZ in an Aquaplanet GCM

Mishra, Saroj K and Srinivasan, J and Nanjundiah, Ravi S (2008) The Impact of the Time Step on the Intensity of ITCZ in an Aquaplanet GCM. In: Monthly Weather Review, 136 (11). pp. 4077-4091.

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Abstract

Several numerical experiments have been conducted using the NCAR Community Atmosphere Model, version 3 (CAM3) to examine the impact of the time step on rainfall in the intertropical convergence zone (ITCZ) in an aquaplanet. When the model time step was increased from 5 to 60 min the rainfall in the ITCZ decreased substantially. The impact of the time step on the ITCZ rainfall was assessed for a fixed spatial resolution (T63 with L26) for the semi-Lagrangian dynamical core (SLD). The increase in ITCZ rainfall at higher temporal resolution was primarily a result of the increase in large-scale precipitation. This increase in rainfall was caused by the positive feedback between surface evaporation, latent heating, and surface wind speed. Similar results were obtained when the semi-Lagrangian dynamical core was replaced by the Eulerian dynamical core. When the surface evaporation was specified, changes in rainfall were largely insensitive to temporal resolution. The impact of temporal resolution on rainfall was more sensitive to the latitudinal gradient of SST than to the magnitude of SST.

Item Type:	Journal Article
Publication:	Monthly Weather Review
Publisher:	American Meteorological Society
Additional Information:	Copyright of this article belongs to American Meteorological Society.
Department/Centre:	Division of Mechanical Sciences > Centre for Atmospheric & Oceanic Sciences
Date Deposited:	20 Aug 2009 11:59
Last Modified:	19 Sep 2010 04:57
URI:	http://eprints.iisc.ac.in/id/eprint/17528

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