Test Case 3: Fire stratocumulus

This test case is a 3 dimensional run which requires the radiation code. This page provides the background information on test case 3 and examples of run of test case 3 on various machines.

Background information (from Jon Petch)

The extensive sheets of stratus and stratocumulus found on the eastern side of ocean basins may have a strong influence of the planet's climate. FIRE (First International satellite cloud climatology project Regional Experiment) was an observational campaign designed to study the stratocumulus sheets off the coast of California in some detail. This case, which is based on the observations of Hignett (1991, JAS) and similar to a EUROCS model intercomparison, examines the impact of short-wave radiation on the boundary layer dynamics and thence the cloud thickness. Stratocumulus sheets are usually located at the top of a mixed layer beneath a strong inversion. The cloud is maintained by moist fluxes through this mixed layer. However, during the day, short-wave radiation is absorbed by the cloud, warming the cloud layer and decoupling it from the mixed layer below. This reduces the moist fluxes into the cloud layer so that continued short-wave warming and mixing with dry air from above the inversion cause the cloud to thin. At nighttime, the cloud cools by long-wave radiation and recouples with the mixed layer so that, with the resumption of moisture fluxes into the cloud layer, the cloud thickens again.

This case is initiated with a nocturnal stratocumulus sheet but at a local time of 10am. Thus the thinning process due to the incident solar radiation can be seen clearly over the three hour simulation in the time-series of liquid water path, cloud base and cloud top below. Some example flux profiles, averaged over the last three hours of the run, are also shown.

Cloud timeseries.

Cloud, vapour and TL flux profiles. Water vapour flux and radiative flux profiles.

This case is a good example of the use of the LEM with non-precipitating moist processes and interactive radiation with high vertical resolution.

Files required to run test case 3

The files needed to run this test case can be found in /home/lem/VER2.3/TEST_CASES/TEST3_2.3 and the table below indicates which files you'll need for which machines

	Turing (T3E - no longer available)	Department machines	Origins (i.e. wren, fermat or green)	Newton
run...f	runTEST3_2.3.f	runTEST3_2.3-m.f	runTEST3_2.3-w.f	runTEST3_2.3-w.f
end...f	endTEST3_2.3.f	endTEST3_2.3.f	endTEST3_2.3.f	endTEST3_2.3.f
nmlsetup...	nmlsetupTEST3_2.3-t	nmlsetupTEST3_2.3-m	nmlsetupTEST3_2.3-w	nmlsetupTEST3_2.3-w
nmlchain...	nmlchainTEST3_2.3	nmlchainTEST3_2.3	nmlchainTEST3_2.3	nmlchainTEST3_2.3
model...	modelTEST3_2.3-t	modelTEST3_2.3-m	modelTEST3_2.3-w	modelTEST3_2.3-n

Runs for Test Case 3

Computer	Run No	Version	PEs	IIP, JJP, KKP	Time Taken	Results
Newton	126	2.3	10	80, 80, 100	4.50 hrs	Cloud timeseries Cloud, ... profiles Water vapour, ... profiles
Origins	25	2.3	10	80, 80, 100	unknown	Cloud timeseries Cloud, ... profiles Water vapour, ... profiles
GRID	55	2.3	1	32, 32, 100	117 hrs	Cloud timeseries Cloud, ... profiles Water vapour, ... profiles
T3E at Met Office	N/A	2.2	10	80, 80, 100	unknown	Cloud timeseries Cloud, ... profiles Water vapour, ... profiles
Turing	706	2.2	10	80, 80, 100	unknown	Cloud timeseries Cloud, ... profiles Water vapour, ... profiles