Improvements to GFDN Planned for Operational Implementation in 2008

Morris Bender, Timothy Marchok (GFDL) Isaac Ginis, Biju Thomas, Richard Yablonsky (URI) Carey Dickerman and Roger Stocker (FNMOC)

LAST MAJOR GFDN UPGRADE WAS IN 2003 !!!THIS HAS RESULTED IN STEADY DECREASE IN MODEL RELIABILITY

COMPARED TO THE WEATHER SERVICE’S VERSION OF THE GFDL MODEL

4 YEAR AVERAGE TRACK SKILL 4 YEAR AVERAGE INTENSITY SKILL

GFDL

GFDN GFDN

GFDL

GFDN model Physics and Resolution will be consistent with NCEP’s GFDL Model

• Addition of Third Mesh (Doubling of the Innermost Resolution to 1/12 degree)

• Upgrade with NCEP’s Ferrier Micro-physics

(Replaces simplified large-scale condensation)• Dissipative Heating Effect Added• Improved Surface Momentum Fluxes Derived

from Wave Model

SUMMARY OF 2008 GFDN MODEL UPGRADES

CURRENT GFDL COUPLED TO PRINCETON OCEAN MODEL (POM) SINCE 2001

CURRENT GFDN MODEL IS STILL UNCOUPLED !!

NEW GFDN MODEL WILL BE COUPLED TO AN OCEAN MODEL IN ALL WORLD BASINS

•Coupled to 3d version of POM model in Atlantic (Identical to current version operational in GFDL)•Coupled to 1d Version of POM in all Other Ocean Basins (e.g.,Epac, Wpac, Indian Ocean, South Pacific)(Current GFDL coupled to 1d version of POM in Eastern and Central Pacific)• Improved Loop Current Initialization in the Atlantic(Will also be made operational in GFDL and HWRF in 2008)•Ocean to be initialized by the Navy Coupled Ocean Data Assimilation (NCODA) model on a daily basis.

Improved Detail with High Resolution NCODA Ocean Data Set

CLIMATOLOGY NCODA DATA

NOGAPS SSTs

Temperatures at 75 m

NCODA SSTs

Temperatures at 75 m

IMPROVED TRACK AND INTENSITY SKILL AT ALL TIME LEVELS FOR SELECTED WPAC CASES (2005-2007)

AVERAGE TRACK SKILL AVERAGE INTENSITY SKILL

Removal of Severe West Bias in Tropical Storm Wukong (August 2006)

1 OLD GFDN

2 NEW GFDN

1 OLD GFDN2 NEW GFDN

Modest Improvement for Typhoon Cimaron (October 2006)

1 OLD GFDN

2 NEW GFDN

1 OLD GFDN

2 NEW GFDN

Mixed Result for Typhoon NESAT (June 2005)

1 OLD GFDN

2 NEW GFDN

1 OLD GFDN

2 NEW GFDN

INITIAL TEMPERATURES AT THE 75 METER DEPTH

72H FORECASTED SSTs

IMPROVED INITIALIZATION OF LOOP CURRENT & OCEAN EDDIES

HURRICANE KATRINA (INITIAL TIME: 1200 UTC 26 AUGUST

IMPROVED INTENSITY PREDICTION FOR KATRINA WITH BETTER INITIALIZATION OF LOOP CURRENT AND OCEAN EDDIES

1 OPERATIONAL 2005 GFDL

2 CURRENT LOOP CURRENT

3 NEW LOOP CURRENT

1 OPERATIONAL 2005 GFDL2 CURRENT LOOP CURRENT3 NEW LOOP CURRENT

CENTRAL PRESSURE (hPa) MAXIMUM SURFACE WINDS (Knots)

1200 UTC 26 AUGUST

IMPROVED PREDICTION OF HURRICANE DEAN (2007) WITH UPGRADED GFDN

IMPROVED TRACK SKILL FOR DEAN

AVERAGE TRACK SKILL

NORTH BIAS ENTIRELY REMOVED

1 GFDL

2 NEW GFDN

3 OLD GFDN

AUG. 16, 0Z

AUG. 16, 12Z

CONSISTENT TRACK PREDICTION WITH NEW GFDN MODEL FOR ALL OF DEAN

COMPOSITE OF TRACKS FOR NEW GFDN

PREDICTED MAJOR HURRICANE STATUS

MA

XIU

M S

UR

FA

CE

WIN

DS (K

NO

TS

)

CAT 3

CAT 4

1 GFDL2 NEW GFDN3 OLD GFDN

AUG. 16, 0Z

AUG. 15, 18Z

SUMMARY

• GFDN MODEL TO BE UPGRADED WITH PHYSICS AND RESOLUTION CONSISTENT WITH PRESENT VERSION OF NCEP’S GFDL MODEL

• TEST RESULTS INDICATED SIGNIFICANTLY IMPROVED RELIABILITY BOTH FOR TRACK AND INTENSITY PREDICTION WITH THE UPGRADED GFDN MODEL

• IMPROVED PREDICTION INDICATED FOR HURRICANE DEAN (2007) AT ALL OF THE LEAD TIMES

• GFDN, GFDL AND HWRF MODELS TO BE UPGRADED WITH IMPROVED INITIALIZATION OF THE LOOP CURRENT AND OCEAN EDDIES IN THE GULF OF MEXICO