History of GFDL hurricane group and highlights of its research

1. History of GFDL hurricane group and highlights of its research Robert E. Tuleya (GFDL retired & CCPO/ODU) May 2, 2017 GFDL Hurricane Symposium

2. Tropical cyclone model vs. Extra-tropical/global modelduring dawn of numerical weather prediction and simulation Specifically for tropical cyclone Locally forced (latent heating) Limited data available in tropics over oceans Spans scales from cumulus through synoptic Variety of wx systems (fronts, cyclones, etc) Linear instability (baroclinic, barotropic) Relevant data more available Cumulus scale less important

3. Y. Kurihara with GFDL’s Founder Joe Smagorinsky “This is to reaffirm our telephone conversation of about a week ago on the above subject and to add some details. Starting FY71, Dr. Yoshio Kurihara will be spending full time on the hurricane genesis/propagation problem…..” Joseph Smagorinsky to Robert White (ESSA head) … 7/1/1970

4. Development of Box Method (1967,MWR) the sole surviving a-grid model !??

5. A different erauni programing, card decks, magnetic tapes, no computer graphics,even before TRS-80! https://en.wikipedia.org/wiki/Computer_programming_in_the_punched_card_era

6. CHRONOLOGY of HURRICANE MODELING at GFDL １９９５ １９８６ ２０００ １９７０ １９９０ １９８０ Hurricane Project established Movable Nested Mesh Model Conversion Work started GFDL Hurricane PredictionSystem adopted by NOAA & NAVY Upgrade Model, Climate Studies based onKuri’s talk at 50th GFDL anniversary

8. GFDL nested model GFDL hurricane model becomes operational 1st 3D Hurricane model R30L18 T126L18 T170L42 T574L64 Operational GFS model resolution ---> 70km 38km 23km

9. Early 3-D hurricane models NHRL(HRD)Anthes, Rosenthal, Trout, 1971 GFDL Kurihara, Y., and R. E. Tuleya, 1974 Evolved into MM5 model 3-D model on stretched grid

10. TC genesis-impact of environmentKurihara, Y., and R. E. Tuleya, 1981, MWR Tuleya and Kurihara, 1981, MWR Preference for easterly vertical shear Wave  TC Effect of shear

11. Nested Grid System(an impressive scientific tool !)Kurihara, Y., G. Tripoli and M. Bender, 1979, MWR

12. GFDL Hurricane Group (~1990)

13. Impacts on and by TCBender,M.A, R.E. Tuleya and Y. Kurihara,1987,MWRRoss, R. J., and Y. Kurihara, 1995,MWR with without Topographical impact TC’s impact on coastal front

14. Asymmetries & relative flow Hurricane Landfallimpact of beta effect reduction of surface evaporationTuleya, Bender, Kurihara, MWR, 1984Bender (JAS,1997) Tuleya (MWR, 1994)

15. Effect of stability… vertical shearShen, Tuleya, and Ginis 2000, J.Clim.Tuleya, Bender, Knutson, Siurtis, B Thomas, and I Ginis, JAS (2016) Slight preference for easterly vertical shear for weak initial systems ‘. Preference as easterly shear increases for robust initial systems due to ocean coupling

16. Addition of visiting scientists Ginis & Wu

17. Other Research • Time differencing scheme (Tripoli) • Lateral boundary conditions • Convective adjustment scheme • Idealized & model spiral band analyses • Vortex specification • Hurricane eye • Rainfall evaluation • Ocean interaction (Ginis) • Hurricane & Climate(Knutson)

18. Development of Operational System(includes vortex initialization, boundary conditions, & model)Bender, Ross, Tuleya and Kurihara, 1993, MWRKurihara, Y., R. E. Tuleya, and M.A. Bender, 1998 , MWR Improved initial condition Gloria (1985) 1st real data case by nested hurricane model

19. Jerry Mahlman director during operational implementation of GFDL Hurricane Model GFDL Science and Athletics J.Mahlman to W. Bonner,NMC, 7/16/86

20. Issues in model development and transitions to operations • Morris very enthusiastic and focused • Thank You Chris Kerr Biju Thomas and Matt Morin • Roadblocks to progress comes from unexpected sources

21. Where do we (you) go from here?? • Transition to HWRF complete • Impact of HFIP & FV3 • Impact of assimilating more storm data • Deterministic vs Probabilistic intensity forecasts • Global vs Regional Models

22. Thank you Kuri!!!!

23. Congratulations Morris!!