Upgrades to the GFDL/GFDN Hurricane Model for 2014 (A JHT Funded Project) Morris A. Bender, Matthew Morin, Timothy Marchok, Isaac Ginis, Biju Thomas, Richard Yablonsky and Robert Tuleya
68th Interdepartmenal Hurricane Conference Tuesday, March 5th GFDL 2014 Hurricane Model Upgrade
• Increased horizontal resolution of inner nest from 1/12th to 1/18th degree with reduced damping of gravity waves in advection scheme • Improved specification of surface exchange coefficients (ch, cd) and surface stress computation in surface physics • Improved specification of surface roughness and wetness over land. • Modified PBL with variable Critical Richardson Number. • Advection of individual micro-physics species. (Yet to test impact of Rime Factor Advection) • Improved targeting of initial storm maximum wind and storm structure in initialization. (Reduces negative intensity bias in vortex specification) • Remove vortex specification in Atlantic for storms of 40 knots and less • Upgrade ocean model to 1/12th degree MPI POM with unified trans-Atlantic basin and 3D ocean for Eastern Pacific basin • Remove global_chgres in analysis step (direct interpolation from hybrid to sigma coordinates) New Cd and Ch formulation
New Ch New Cd Current HWRF and GFDL Cd
Current HWRF Ch Comparison of New cd and ch with Recent Referenced Studies Cd Ch Impact of Bogusing on Intensity Errors For Storms 40 knots or less
Bogus No Bogus Bogusing Significantly Atlantic Degraded performance in Atlantic for weak systems
No Bogus Bogus Bogusing Eastern Significantly Improved Pacific Performance in Eastern Pacific VERTICAL CROSS-SECTION FOR UNBOGUSED INITIAL CONDITION THROUGH STORM CENTER
Hurricane Earl th Total August 26 , 12z, 2010 Wind Speed (knots)
Tropical Storm Bud Hurricane Mariam nd May 22nd , 6z, 2012 September 22 , 6z, 2012 Impact of Bogusing in Atlantic and Eastern Pacific Hurricane Earl August 26th, 12z, 2010
New GFDL Unbogused New GFDL Bogused
Tropical Storm Bud Hurricane Mariam May 22nd , 6z, 2012 September 22nd, 6z, 201212 Bogused
Unbogused Bogused Unbogused New GFDL Model Significantly Improved Intensity Skill at all Time Levels In Both Basins
Atlantic
Eastern Pacific Percent of Storms which have Improved Intensity Forecasts with new model
For days 3-5 over 80% of storms in the Atlantic Atlantic have improved Intensity Guidance
For days 3-5 Eastern 60% of storms in the Eastern Pacific Pacific have improved Intensity Guidance
Overall Reduced Intensity Bias with New GFDL Model Much Reduced Over-Intensification Tendency for Weaker Storm Intensity with New Model Hurricane Isaac Hurricane Katia nd August 22 , 12z, 2012 Current GFDL August 29th, 18z, 2011 Current GFDL New GFDL
Current GFDL New GFDL Current GFDL New GFDL New GFDL
Hurricane Maria Hurricane Philippe th September 9th, 12z, 2011 September 28 , 6z, 2011 Current GFDL Current GFDL
New GFDL New GFDL Current GFDL New GFDL Improved Intensification for Developing Hurricanes with New GFDL Model Hurricane Danielle Hurricane Earl rd August 23 , 6z. 2010 August 27th, 18z, 2010 New GFDL New GFDL
Current GFDL
Current GFDL Current GFDL New GFDL
Hurricane Igor Hurricane Ike September 11th, 0z, 2010 September 3rd, 12z, 2008 New GFDL
New GFDL Current GFDL Current GFDL Current GFDL New GFDL Neutral Impact on Track Errors
Atlantic
Eastern Pacific Examples of Track Improvement In Atlantic
Tropical Storm Lisa September 22nd , 0z, 2010 Current GFDL
New GFDL
Current GFDL
Hurricane Irene Current GFDL August 21st, 12z, 2011 New GFDL
Hurricane Ernesto August 6z, 0z, 19`1 New GFDL
New GFDL
Current GFDL
Hurricane Ophelia September 22nd, 0z, 2011 Compared to Current Model New Model Demonstrated Some Reduction in North Bias for Storms Near Mexican Coast Hurricane Dalila Hurricane Dalila July 1st, 12z, 2013 July 2nd , 12z, 2013
Current GFDL Current GFDL
New GFDL HWRF New GFDL
New GFDL Current GFDL Current GFDL HWRF
HWRF
Tropical Storm Kristy Tropical Storm Kristy September 12th, 12z, 2012 September 13th, 12z, 2012 Preliminary GFDL/HWRF Comparison
TRACK GFDL HWRF GFDL
ATLANTIC EASTERN PACIFIC
HWRF HWRF GFDL INTENSITY GFDL New GFDL model will run in near real time in the Western Pacific on Jet Computer system during summer 2014
Earlier Study Demonstrated superior track performance in WPAC for GFDL model run from GFS boundary conditions • 25% reduction in GFDL average track error at days 2, 3 and 4 • 15% reduction at day 5 when run from GFS analysis compared to NOGAPS Example of New GFDL performance in Western Pacific (Typhoon Haiyan) New GFDL Initial Time: November 5th, 2013, 0z
HWRF GFS NavGEM Current GFDN
HWRF New GFDL GFDN DSHP New GFDL HWRF New GFDL Surface winds (knots) Central Pressure (hPa)