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Chapter 5. Convection
IFS documentation Front Page
Chapter 1. Overview
Chapter 2. Radiation
Chapter 3. Turbulent diffusion and interactions with the surface
Chapter 4. Subgrid-scale orographic drag
Chapter 5. Convection
Chapter 6. Clouds and large-scale precipitation
Chapter 7. Land suface parametrization
Chapter 8. Methane oxidation
Chapter 9. Climatological data
REFERENCES
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5.2 Large-scale budget equations
The contributions from cumulus convection to the large-scale budget equations of heat moisture and momentum are
|
(5.1) |
where
, 
are the net contributions from all clouds to the
updraught and downdraught mass fluxes, 
and 
are the condensation/sublimation in the updraughts, and the evaporation
in the downdraughts. 
, 
, 
, 
, 
, 
, 
and 
are the weighted averages of the dry
static energy (
), the specific humidity (
), and the horizontal wind components (
and 
) from all updraughts and downdraughts within a
grid box (although individual convective elements are not considered) obtained
from the bulk cloud model described below. 
and 
are latent heats of sublimation and
vaporization, and 
is the effective
latent heat for an ice-water mix (an empirical function of temperature).
is the evaporation of precipitation
in the unsaturated sub-cloud layer, 
is the melting
of snow and 
is the freezing of condensate in the
convective updraught. In addition to (5.1) we consider the equations for precipitation
|
(5.2) |
where
and 
are the fluxes of precipitation in the forms
of rain and snow at height z. 
and 
are the conversion rates from cloud water into rain and cloud
ice into snow. The evaporation of precipitation in the downdraughts 
, and below cloud base 
, have been
split into water and ice components, 
, 
, 
, and 
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05.04.2002 |
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