A.b.ii. Surface flux parameterization
|
Surface momentum and heat fluxes are given by the bulk formulae of
Louis (1979).
The bulk coefficient for heat transport and momentum is
equivalent. In this study, surface fluxes must be treated with care
since diurnal change is taken into consideration and since focus is
placed on the magnitude of surface stress estimated by the surface
momentum flux. Surface fluxes significantly change with atmospheric
stability. The surface flux parameterization presented by Louis (1979)
can be used to easily represent the dependence of surface flux on
atmospheric stability.
are the horizontal wind and temperature at the lowest level of the model atmosphere .
is the surface temperature. The bulk
coefficient is calculated as follows.
![](../eqns/img119.gif) |
(A.16) |
where,
![](../eqns/img120.gif) |
(A.17) |
and
is the Karman constant (= 0.35), is the roughness length.
The roughness length
is 1 cm (
Sutton et al., 1978).
is the bulk Richardson number, which is given as follows.
![](../eqns/img123.gif) |
(A.18) |
where
are the potential temperature and
horizontal mean potential temperature at the lowest level of the
model atmosphere.
is the potential temperature of ground surface
(= ).
|