D. Gregory and F. Guichard

Q.J.R. Meteorol. Soc.,submitted October 2000

Cloud resolving model simulations of organised tropical convection in TOGA-COARE are used
to evaluate versions of the ECMWF convection scheme and cloud schemes in single column model
simulations. Emphasis is placed upon the ability of the convection scheme to represent "cloud scale"
processes, with a typically mode 1 heating structure through the troposphere, with the cloud scheme
representing the stratiform (mesoscale) component with upper level heating and low level cooling due to
the evaporation of precipitation. While diagnosis of convective and stratiform precipitation is sensitive
to the sampling criteria applied to the CRM, vertical structures of the mass and heat budgets are robust.
Using diagnostics from the cloud resolving model simulations as a guide, revisions to the convection and
cloud schemes are suggested in order to enable the parametrization to represent the two scales. The
study suggests that a mass flux convection scheme linked via detrainment to a prognostic treatment of
cloud can represent organised convection provided the upward motion in the upper level stratiform cloud
is considered.

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