National Center for Atmospheric Research - Mesoscale and Microscale Meterology (NCAR/MMM)

Domains

Horizontal

• 12 km (469 by 424)
• MMM1: 12 km grid
• 12 km (469 by 424) / 4 km (202 by 202) / 1.33 km (241 by 241) )
• MMM3: 1.33 km grid
• MMM4: 4 km grid

Vertical

36 full levels with model top at 20 mb

Atmosphere

Model: WRF ARW V3.0.1.1

Overview

The WRF model is designed to be a flexible, state-of-the-art, portable code that offers two dynamic solvers and numerous physics options. The Advanced Research WRF (ARW) solver developed at NCAR, utilizes the Arakawa C grid on several different projections and a terrain-following mass coordinate. The ARW also employs higher order numerics for advection and time integration. For this test, the ARW is configured using the Lambert-Conformal projection with one static domain and either one or two moving, two-way interactive nested domains. For more detailed information on the ARW, please see Skamarock et al, 2008.

View a subset of the configuration

Initialization

EnKF method in a 6-hour cycling mode, with WRF ARW V2.2 on a 36-km grid, assimilating surface pressure, rawinsonde (including G-IV dropsondes), ACARS, cloud motion vectors and tropical cyclone best track data each six hours.  Six-hour forecasts on the lateral boundaries are taken from the one-degree six-hour GFS forecast valid at the appropriate time.  The ensemble is initialized roughly two days prior to being classified as a depression by adding balanced perturbations from the WRF-Var system to the GFS 36-h forecast valid at the appropriate time.  Using an old forecast with high amplitude perturbations helps the ensemble develop a flow-dependent ensemble quicker than starting from short-term forecasts.

Lateral Boundary Conditions

6-h GFS forecast output on 1 deg grid

Physics

Cumulus	new Kain Fritsch (12 km only)
Microphysics	WSM 5
PBL	YSU
Surface Layer	Monin-Obukov
Land Surface	5-layer thermal diffusion soil model
Radiation	RRTM (longwave) / Dudhia(shortwave)

Ocean

1-D ocean mixed-layer model

Initialization

Based on daily HYCOM temperature fields.
SST from real-time global 0.5 and 0.0833 (when it was available) degree daily analysis (from NCEP).

Archival

Entire model output archived

References

Skamarock, W. C., J. B. Klemp, J. Dudhia, D. O. Gill, D. M. Barker, W. Wang and J. G. Powers, 2008: A Description of the Advanced Research WRF Version 3. NCAR Technical Note TN-468+STR. 113 pp