ASM Project Update:Atmospheric Modeling
John J. Cassano and Mark W. Seefeldt
University of ColoradoCooperative Institute for Research in Environmental Sciences
Department of Atmospheric and Oceanic Sciences
Goals for Year 1 of DOE Project
• Develop and evaluate Polar WRF– Univ. of Colorado– Sub-contract to Bromwich / Hines - OSU
• Coupling of WRF to CCSM cpl7– Lead by Juanxiong He, UAF
Strategy for Polar WRF Development
• Use lessons from development of Polar MM5• Identify parameterizations that are well-suited for polar
use• Preference for parameterizations that are most physically
realistic• Add “missing” physics• Collaboration with several research groups
– OSU / BPRC– NOAA ESRL– NCAR– University of Colorado
Polar WRF Evaluation• Evaluate over a variety of polar surface types
– Ice sheet (Hines / Bromwich - Greenland)– Sea ice / ocean (Hines / Bromwich and CU - SHEBA)
• Implementation of fractional sea ice treatment (OSU)– Non-ice covered land
• Evaluate atmospheric state• Evaluate atmospheric processes
– Are we getting the right answer for the right reasons?• Initial work at University of Colorado
– Identify parameterizations that are inappropriate for polar use– Identify “ideal” suite of model parameterizations– Identify aspects of model in need of improvement
SHEBA Simulations• Simulations during SHEBA year
– January and June 1998 (CU) - climate mode– January, June, and August 1998 (OSU) - forecast mode
• Model forcing (CU)– ECMWF TOGA
atmospheric data and SST– ERA40 sea ice and
soil state• Model grid (CU)
– 50 km horizontal– 31 vertical levels– Model top: 50 mb
WRF Physics• Land surface: Noah (Thermal diffusion)• Longwave radiation: RRTM• Shortwave radiation: Goddard (Dudhia)• Boundary layer: YSU (MYJ)• Microphysics: Morrison (WSM5)• Cumulus: Kain-Fritsch (Grell-Devenyi)
• Bromwich / Hines have used a slightly different selection of model physics for their Greenland and SHEBA simulations
Shortwave Radiation: Goddard and DudhiaGoddard SW
Dudhia SW
June 1998RRTM LW
WSM5 MP
KF CU
YSU PBL
Noah LSM
Land surface: Noah LSM and thermal diffusionNoah LSM
Thermal diffusion model
January 1998Dudhia SW
RRTM LW
WSM5 MP
KF CU
YSU PBL
Cumulus: Kain-Fritsch and Grell-DevenyiKain-Fritsch
Grell-Devenyi
June 1998Goddard
RRTM LW
Morrison MP
MYJ PBL
Noah LSM
Cumulus: Kain-Fritsch and Grell-DevenyiKain-Fritsch
Grell-Devenyi
June 1998Goddard
RRTM LW
Morrison MP
MYJ PBL
Noah LSM
Cumulus: Kain-Fritsch and Grell-DevenyiKain-Fritsch
Grell-Devenyi
June 1998Goddard
RRTM LW
Morrison MP
MYJ PBL
Noah LSM
Boundary Layer: YSU and MYJYSU
MYJ
January 1998Goddard
RRTM LW
Morrison MP
KF CU
Noah LSM
Cloud Microphysics: Morrison and WSM5Morrison
WSM5
January 1998Goddard
RRTM LW
KF CU
YSU PBL
Noah LSM
Cloud Microphysics: Morrison and WSM5Morrison
WSM5
June 1998Goddard
RRTM LW
KF CU
YSU PBL
Noah LSM
Polar WRF and Polar MM5Polar WRF
Polar MM5
January 1998Goddard
RRTM LW
Morrison MP
KF CU
YSU PBL
Noah LSM
Polar WRF and Polar MM5Polar WRF
Polar MM5
January 1998Goddard
RRTM LW
Morrison MP
KF CU
YSU PBL
Noah LSM
Polar WRF and Polar MM5Polar WRF
Polar MM5
June 1998Goddard
RRTM LW
Morrison MP
KF CU
YSU PBL
Noah LSM
Polar WRF and Polar MM5Polar WRF
Polar MM5
June 1998Goddard
RRTM LW
Morrison MP
KF CU
YSU PBL
Noah LSM
Polar WRF and Polar MM5Polar WRF
Polar MM5
June 1998Goddard
RRTM LW
Morrison MP
KF CU
YSU PBL
Noah LSM
Conclusions: Polar WRF Development• Some WRF physics options are clearly inappropriate for
polar applications– Dudhia SW: large negative bias in SWD– Thermal diffusion soil model: large warm bias
• There appear to be issues with other physics options, which need more analysis– Grell-Devenyi cumulus: excessive cloud cover– MYJ PBL: wintertime cold bias
• Polar WRF has better skill than PMM5 for Jan• Polar WRF has similar skill as PMM5 for June • Processes in Polar WRF appear more realistic than in
Polar MM5
Meetings, Presentations, and Publications
• Conferences– DOE CCPP Science Team Meeting (Sept 07)
• Poster overview of RACM project– SEARCH for DAMOCLES (Oct 07)
• Atmospheric Modeling in an Arctic System Model• Polar Optimized WRF
– Little Alaska Weather Symposium (May 08)• Development and evaluation of Polar WRF
• Publications• Bromwich, D.H., K.M. Hines, and L.-S. Bai, 2008:
Development and testing of Polar WRF. Part II. The Arctic Ocean, submitted to J. Geophys. Res.