Mesoscale Parallel Experiment Log for " Eta-32 with reduced aerodynamic resistance and reduced canopy resistance to transpiration "

Mesoscale Parallel Experiment Log

Experiment Name: Eta-32 with reduced aerodynamic resistance and redeuced canopy resistance to transpiration
Parallel Slot: ETAL
Control Slot: ETAV
Start date of parallel experiment: 12Z 2002/10/08
End date of parallel experiment: 00Z 2002/10/30
Environmental Modeling Center scientists: Mike Ek, Ken Mitchell, Geoff Manikin, Eric Rogers
Abstract (including Motivation, Hypothesis and Method): The Eta-32 parallel system is being used to test changes to the model land-surface scheme to reduce warm 2-m temperature biases
FORECAST MODEL CHANGES

Reduced parameter CZIL reduced from 0.2 to 0.07. This change will reduce aerodyamnic resistance (i.e. surface turbulent exchange coefficients are too low during mid-day)
Reduced canopy resistance to transpiration; the vapor pressure (relative humidity) stress term therein is too strong and acts in a too heavy handed fashion to close the canopy leaf stomata too agressively during mid-day transpiration. Hence the latent heat flux is modestly too low over non-sparse green vegetation regions (eastern half of U.S. from late spring, thru summer, thru early Fall), even when we have good soil moisture.
Experiment changes log
Background links
Evaluation of parallel results: Daily forecast maps; Daily forecast stats; Verification of precipitation and against rawinsondes / surface data
Conclusion

Page Last Modified: January 16, 2002