RCM Characteristics

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RCM Characteristics

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RCM Characteristics

Major Characteristics of Regional Climate Models Participating in NARCCAP

	CRCM	ECPC/ECP2	HRM3	MM5I	RCM3	WRFP/WRFG
Dynamics	Nonhydrostatic, Compressible	Hydrostatic, Incompressible	Hydrostatic, Compressible	Nonhydrostatic, Compressible	Hydrostatic, Compressible	Nonhydrostatic, Compressible
Lateral Boundary Treatment	9 points (Davies 1976); spectral nudging of horizontal wind.	Perturbations relaxed at boundaries; spectral filter	4 points (Davies and Turner 1977)	4 points (linear relaxation)	12 points (exponential relaxation)	15 grid points (exponential relaxation)
Land Surface	CLASS	NOAH	MOSES	NOAH	BATS	NOAH
Thermal/Water Layers	3/3	4/4	4/4	4/4	1/3	4/4
Vegetation Types	21 vegetation classes	13 classes	53 classes (Wilson and Henderson- Sellers 1985)	16 classes from USGS SiB model	19 classes	24 classes from USGS
Boundary Layer	Local K, gradient Richardson number formulation	Hong-Pan non-local K	First order turbulent mixing	Hong-Pan (MRF) countergradient, non-local K	Non-local K, countergradient flux	Yonsei Univ. (explicit entrainment)
Explicit Moist Physics	Removal of supersaturation	Removal of supersaturation	Prognostic cloud liquid and ice; liquid potential temperature	Dudhia simple ice	SUBEX, prognostic cloud water	Prognostic cloud liquid and ice, rain, snow
Cumulus Parameterization	Mass Flux	Simplified Arawaka- Schubert	Mass Flux, including downdraft	Kain- Fritsch2 mass flux	Grell with Fritsch- Chappell closure	Kain- Fritsch2 mass flux [WRFP] / Grell [WRFG]
Number of Vertical Levels	29	28	19	23	18	35
Type of Vertical Coordinate	Gal-Chen scaled-height	Normalized pressure	Hybrid terrain following & pressure	Sigma	Terrain following	Terrain following
Original Grid Size*	160 x 135	193 x 152	171 x 146	154 x 129	160 x 130	155 x 130
Sponge Zone Depth (pts)**	10	23 (x) / 18 (y)	8	15	13	10.5
Length of Timestep	900 Seconds	100 seconds	300 Seconds	120 seconds	150 Seconds	150 seconds
tasmin/tasmax Calculation***	timestep	timestep	timestep	timestep	3-hourly	hourly
Spectral Nudging	Yes	Yes	No	No	No	No
Longwave Radiation Scheme	Morcrette (1984)	Chou and Suarez (1994)	PRECIS	RRTM	CCM3	CAM3
Shortwave Radiation scheme	Fouquart and Bonnel (1980)	Chou (1992)	PRECIS	MM5 cloud scheme (not CCM2)	CCM3	CAM3
Uniform Aerosols?	No	Yes	No	Yes	Yes	Yes* *(ozone varies)

* Original Grid Size: The original ECPC run had a smaller domain, 161 x 136, with a spong depth of 7 / 10.

** Sponge Zone Depth: Values given are depth along each edge. Total points removed from each dimension are twice the given values.

*** tasmin/tasmax Calculation: the frequency of the values from which daily minimum and maximum temperature values (variables tasmin and tasmax) are calculated. "Timestep" means that min and max values are updated on every internal timestep of the model. "Hourly" and "3-hourly" mean that min and max are calculated from tas values recorded at hourly/3-hourly intervals.

The National Center for Atmospheric Research is sponsored by the National Science Foundation. Any opinions, findings and conclusions or recommendations expressed in this material do not necessarily reflect the views of the National Science Foundation.