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.