Large Scale Condensation and Precipitation

Summary

The module computes the large scale temperature and specific humidity adjustments needed in model layers where the relative humidity exceeds a threshold relative humidity, and returns the mass of rain and snow (or other frozen precipitation) that reaches the ground. The module also outputs the temperature tendency and the specific humidity tendency. Features include the option for the re-evaporation of falling precipitation and energetically consistent adjustment with precipitation type.

See [Frierson2006a] (Section 2e) for a detailed description here.

Namelist options

There are three namelist variables.

hc:

The relative humidity at which large scale condensation, where \(0.0 <= hc <= 1.0\). Default is \(hc=1.0\).

do_evap:

The flag for the re-evaporation of moisture in sub-saturated layers below, if True then re-evaporation is performed. Default is False.

do_simple:

If True then all precipitation is rain/liquid precipitation, there is no snow/frozen precipitation. Default is False.

Diagnostics

The diagnostics are not sent out within the call to convection but are sent out from idealized_moist_phys.F90 with the module name atmosphere. The diagnostics relevant to the lscale_cond module are set out below:

Name

Description

Units

cond_dt_qg

Moisture tendency

\(kg~kg^{-1}~s^{-1}\)

cond_dt_tg

Temperature tendency

\(K~s^{-1}\)

cond_rain

Rain from condensation

\(kg~m^{-2}~s^{-1}\)

precip

Rain and Snow from resolved and parameterised condensation/convection

\(kg~m^{-2}~s^{-1}\)

Relevant Modules and Subroutines

Relevant modules are: sat_vapor_pres_mod, utilities_mod, constants_mod.

References

The reference list within this docs page are: [Frierson2006a]

Authors

This documentation was written by Ross Castle and reviewed by Ruth Geen