Navy Research Priorities for Tropical Cyclones Simon W. Chang 1 and Ronald J. Ferek 2 1 Naval Research Laboratory, Monterey, CA 2 Office of Naval Research, Arlington, VA 62 nd Interdepartmental Hurricane Conference Charleston, SC March 3-7, 2008

Navy Operational Goals For Maritime/Tropical Cyclones Develop and improve cogent communication and articulation of impending hazard/risk Accurate quantification of risk probabilistic Sensitive and adaptable to user timelines and operational constraints Maintain track excellence 5-day requirement (50/100/150/200/250 nm), multi-model ensemble Improve operational forecasting of TC structure and its effects Significant wave spectra, impact on ocean structure, storm surge, precipitation, intensity, ET Develop ability to operationally forecast TC genesis out to 5 days Maintain ATCF capability to meet user requirements (from “Modeling and Automation Requirements in Support of NOOC”, RDML David Titley, CNMOC, 2007)

Navy Research Related to Tropical Cyclones Naval operations depend critically on accurate analysis and prediction of tropical cyclones. Naval Research aligns with operational requirements. Office of Naval Research (ONR) has long-term, extramural, basic and applied research program in tropical meteorology. Two new research initiatives with field campaigns focused on couple atmosphere-ocean problems were launched in FY08. Naval Research Laboratory (NRL) has on-going basic and applied research program. Topics related to tropical cyclones are: tropical wave dynamics, predictability, deterministic and ensemble prediction systems, optimal data selection for assimilation, observation sensitivity, and targeted observations. The Office of the Oceanographer and Navigator of the Navy provides long-term investment for transitioning of observing and prediction systems into operations for atmospheric and ocean analysis and prediction.

Navy Research Priorities For Tropical Cyclones Major research foci: Cyclogenesis and formation Intensification processes Structure and intensity changes Extratropical transition (ET) Air-sea interactions Companion research foci in ocean responses: SST Current and waves Internal structure Transition to operational NWP and Satellite Application systems through on-going transition programs

Navy Research Priorities For Tropical Cyclones Current integrated programs for transition to operational NWP and Satellite Application systems: Strong- and weak-constraint 4DVAR Hybrid (VAR + EnKF), nonlinear data assimilation Observation sensitivity and optimal data selection Air-sea coupled high resolution TC model Spectral element and discrete Galerkin, nonhydrostatic dynamic cores Semi-Lagrangian and semi-implicit numerics Global and mesoscale deterministic and ensemble prediction systems Multi-sensor satellite and NWP data fusion Following slides show some research highlights

Pre-TY Harry Pre-TY Gladys TY Fred Tropical Cyclone Structure 2008 (TCS08) Experiment Emphasis: To improve the capability to predict the evolution of disturbances in the monsoon trough over the western North Pacific (genesis, structure & intensity changes, outer winds, etc.) o Guam Phillipines GOAL: to reduce errors in TC structure and intensity forecasts by 50% within a decade TCS-08 is coordinated with the international T-PARC. TCS-08/T-PARC are jointly supported by Navy, NSF and USAF.

Research to Operation in TCS-08 Observation assets: In 2008 NRL P-3 with Eldora, dropsonde and lidar. AFR C-130 with SFMR, dropsonde, AXBT, and drifting buoys. (First WestPac TC recon since 1993.) For 2010: drifters gliders, profiling floats, buoys, AXBT and AXCD. Specially tailored images of the atmosphere and ocean surface from geostationary and polar-orbiting satellites. SAR images of ocean waves. Numerical testbeds: NOGAPS, COAMPS ®, and associated ensemble prediction systems with 3D/4D VAR data assimilation at NRL and FNMOC. Initial condition (SV/ET) and observation sensitivity products. More than 20 PIs in the research community are funded to participate. Observation and model data available for post-experimental analyses, basic research, and prediction system improvements. New discovery and invention will transition to operations through existing transition programs.

Ocean Mixed Layer Evolution in Hurricanes Building on the Accomplishments of CBLAST Before CBLAST: usual drag coefficient approach, mixing by KPP, Mellor-Yamada Out of CBLAST: wind forcing via the wave based momentum calculation. Use CBLAST Tested Ocean Observation Technologies Major field program in WestPac planned for 2010First workshop in Taipei March 2008

Coupled COAMPS ® with Ocean Circulation Model Use ESMF methodology to couple COAMPS with NCOM ocean circulation and ocean wave models, in conjunction with the BEI project Explore the air-ocean coupled response New Suite of Physical Parameterizations for COAMPS-TC New surface flux parameterization based on CBLAST observations New microphysics development for more accurate TC intensity forecasts Application of new Fu-Liou 4-stream radiation package to TCs New sea spray parameterization New Tropical Cyclone Analysis Technique Development of new TC analysis packages that features relocation of the TC and augmentation with synthetic observations Formulated in NAVDAS (3DVar) framework Improved intensity analysis that is balanced and dynamically consistent High Resolution NWP System For Intensity Forecast

New TC Analysis: TC Isabel Observations: 940 mb, 64 m s -1 New NAVDAS TC Analysis Improves Location, Structure, Intensity and Balance 956 mb 960 mb 980 mb 67 m/s 81 m/s 53 m/s OI Analysis Standard NAVDAS NAVDAS for TC

Min. SLP for Isabel Obs No spray Spray No SpraySpray Sfc. Precip. Rate (78 h) mm h -1 New CBLAST Sea Spray Algorithm (Fairall) implemented in COAMPS shows a more intense cyclone and better organization to the convection for TC Isabel. New Spray Parameterization Based on CBLAST Measurements

Ocean response in coupled COAMPS Cold wake forms in right rear quadrant and dramatically impacts azimuthally averaged flux. Katrina forces a strong cold wake that has an asymmetric impacts on fluxes Cold wake NW SESW NE Total Heat Flux SST Difference: (48h-initial) 12Z 29 Aug 2005 The SST decreases by 7°C in the wake over the 48h period. Evolution of Total Heat Flux

coupled uncoupled 08/28/ UTC /29/ UTC TRMM Model-simulated radar reflectivity indicates that rainband structure is relatively insensitive to the coupling when compared to TRMM estimated precipitation Comparison of Structure Forecast in coupled and uncoupled COAMPS

For probabilistic intensity forecasting: Mesoscale Ensemble ET+Pert physics 48-h forecasts from 00 UTC 09 July 2005 (TC Dennis) Physics perturbations further increase variability in intensity (~987 to 1002 hPa) as well as track among ensemble members (T. Holt, C. Bishop, J. Nachamkin, J. Doyle)

Adjoints of the NOGAPS-NAVDAS are used to calculate the impact of observations on forecast error (Langland and Baker, Tellus 2004). The impact of each type of observation: rawinsonde, dropsonde, particular satellite channels, or temperature vs. wind or humidity can be easily quantified using this method Evaluate the Observation Impact KATRINA case Observations at 00UTC 27 Aug 2005 analysis time (+/- 3 hr) Forecast error reduction Forecast Error Increase Rawinsondes 19 out of 34 reduce 24 h forecast error Dropsondes 11 out of 16 reduce 24h forecast error

COAMPS Moist Adjoint Adjoint Sensitivity for Tropical Cyclogensis COAMPS Moist Adjoint Adjoint Sensitivity for Tropical Cyclogensis J. Doyle, C. Amerault, C. Reynolds TC Fitow (Western Pacific) Adjoint to nonhydrostatic COAMPS ® model Exact adjoint to 6 class microphysics, 1.5 order TKE PBL, and simple cumulus scheme Moist adjoint sensitivity can provide insight into the predictability of tropical cyclones Initial Perturbation Total Energy & SLP Optimal perturbations computed from moist adjoint (24 h) P’=-18 mb U’=30 m s -1 Final Perturbation Total Energy & SLP (24 h) Targeting Implication: Observe Convection in NE Quadrant for This Case

Navy Research Priority in Tropical Cyclones SUMMARY Navy Research programs can contribute to Research Priority topics in Interagency Strategic Research Plan for Tropical Cyclones: The Way Ahead. There are strong basic and applied research programs in all three interagency priority topics: General Research and NWP Modeling NWP Model Development Observations and Observing Strategies Navy integrated research programs in tropical cyclones are being executed in collaboration with other federal agencies, national and international research communities, and operational centers.

Navy Research Priority in Tropical Cyclone The End