Mesoscale Parallel Experiment Log

Experiment Name

Eta-32 with modified thermal conductivity through snow cover

Parallel Slot

ETAL

Control Slot

ETAV

Start date of parallel experiment

00Z 2002/01/23

End date of parallel experiment

00Z 2002/02/22

Environmental Modeling Center scientists

Mike Ek, Ken Mitchell, Eric Rogers

Abstract (including Motivation, Hypothesis and Method)

The Eta-32 parallel system is being used to test a modification to the thermal conductivity through snow and the inclusion of snow cover patchiness in the ground heat flux calculation.
FORECAST MODEL CHANGES

The change to the land-surface scheme (SFLX) in the operational mesoscale Eta model reflects a modification to the thermal conductivity through snow and the inclusion of snow cover patchiness in the ground heat flux calculation, where snowcover can be less than one if snow cover is less that some threshold snow depth (nominally about 12.5-40 cm depending on model surface type and snow density). As such, the ground heat flux is increased, especially under shallow snow cover conditions, resulting in more heat flux from below at night, partially offseting snow-surface nighttime radiative cooling, and subsequently reducing the cold bias in the 2-meter air temperature at night.

Experiment changes log

Implementation changes list

Product changes list

Background links

Evaluation of parallel results

Daily forecast maps

Daily forecast stats

Verification of precipitation and against rawinsondes / surface data

Conclusion

IMPLEMENTED 12Z 2/26/2002

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