TROPICAL CYCLONE STRUCTURE (TCS08) FIELD EXPERIMENT IN THE WESTERN NORTH PACIFIC DURING 2008 Russell L. Elsberry (Naval Postgraduate School) Ronald J. Ferek (Office of Naval Research) Simon Chang (Naval Research Laboratory) Daniel Eleuterio (Naval Research Laboratory) Patrick A. Harr (Naval Postgraduate School) SPONSORS Office of Naval Research Naval Research Laboratory Air Force* National Science Foundation * With thanks to LCOL Kurt Brueske 62 nd Interdepartmental Hurricane Conference, Charleston, SC, 3-7 March 2008

Key science questions to be addressed in a program aimed at increased understanding and predictability of tropical cyclone characteristics during formation, intensification, and recurvature over the western North Pacific Highlights –Incorporates multiple space and time scales Large scale controls –Global and basin-wide spatial scales –Medium-range and synoptic temporal scales Mesoscale organization pathways –During formation –During intensification –Primary hypotheses with respect to: Large-scale role in pre-conditioning or inhibition due to ventilation Mesoscale organizational pathways leading to construction of a potential vorticity monolith –Role of low-level convergence associated with deep convective cells –Stratiform regions of mesoscale convective systems Relative roles of environmental and vortex structures in determining the evolution of the outer wind structure –In tandem with the THORPEX Pacific Asian Regional Campaign (T-PARC) 62nd Interdepartmental Hurricane Conference, Charleston, SC, 3-7 March 2008

FORMATION: SCIENCE HYPOTHESES 62nd Interdepartmental Hurricane Conference, Charleston, SC, 3-7 March 2008 Science hypotheses Mesoscale processes determine the location and timing of tropical cyclone formation within the favorable environment Top-down: MCV near center merges with monsoon depression circulation Bottom-up: Low-level cyclonic vortices form from intense convection in “sweet spot” Environmental processes lead to amplification of the secondary circulation that spin-up the tropical cyclone, but may inhibit via ventilation Concept of operations Global model forecasts for potential cloud clusters Regional model forecasts for likely mesoscale organization Satellite (geostationary and polar-orbiting for continual monitoring, cross- checking against model output, and aircraft briefing and in-flight support)

STRUCTURE: SCIENCE HYPOTHESES 62nd Interdepartmental Hurricane Conference, Charleston, SC, 3-7 March 2008 Environmental dominance: Outer wind structure evolves only slowly from the structure determined at the time of formation Internally determined: Dynamic and thermodynamic imbalances in the inner region generate outward-and-upward-propagating Rossby waves that modify the outer wind structure Super-intensity: Frequent dropwindsonde releases through the eyewall of typhoons will detect structures leading to super-intensity

SPECIAL TCS08 RESOURCES 62nd Interdepartmental Hurricane Conference, Charleston, SC, 3-7 March 2008 AIRCRAFT Naval Research Laboratory P-3 ELDORA (Doppler Radar) Dropwindsondes Flight-level meteorological variables Doppler wind lidar Air Force C-130 reconnaissance aircraft Stepped frequency microwave radiometer (SFMR) Dropwindsondes Flight-level meteorological variables Airborne Expendable BathyThermographs Air Force support aircraft Ocean buoy deployment Taiwan DOTSTAR (if operating near Taiwan)

Combined missions during tropical cyclone formation Use of Eldora to measure characteristics associated with deep convection Doppler Wind Lidar for inflow measurements Use of WC-130 to measure the environmental characteristics BASE OF OPERATIONS AT ANDERSEN AFB, GUAM 62nd Interdepartmental Hurricane Conference, Charleston, SC, 3-7 March 2008

Pre-Pabuk Tropical Wave Lawnmower Pattern PGUM

Man Yi Tropical Storm WC-130J Survey: BUTTERFLY PA~ mb, IAS~ kt (280 kt transit) Leg radii~110 nm 9.5 hr duration 1.5 hr creep/day GPS Dropsonde: 7 sondes per leg +3 = 24 total (eyewall multi- sonde ~5 per leg = +15; 39 total) AXBTs: 7 AXBTs per leg +2 diagonals x4 = 29 total 1944 UTC 10 July 2007 TMI 85 GhZ H PGUM Track Targeting Option Butterfly Pattern

0030 UTC 12 July UTC 12 July 2007 amsre 89 GhZ H PGUM RODN Typhoon WC-130J Survey 700 mb, 220 kt IAS 110 nm radius legs, 7.5 hr duration 7 sondes per profile x 4 = 28 total (eyewall multi-sonde: +5 per profile x 2 = +10 = 38 total; or x 4 = +20 = 48 total); no creep 7 AXBTs per profile x 4 = 28 total Man Yi

SPECIAL TCS08 RESOURCES 62nd Interdepartmental Hurricane Conference, Charleston, SC, 3-7 March 2008 SATELLITE MTSAT Continual monitoring during all phases of operations Rapid scan – desirable during all flight operations Polar-orbiters Microwave for convective structure Scatterometers NUMERICAL MODEL ANALYSES AND FORECASTS Global models (NOGAPS, GFS, UKMO, ECMWF) Environmental conditions in all phases Focus attention on cloud clusters Mesoscale models Naval Research Lab COAMPS Central Weather Bureau NFS and WRF

VALIDATION OF SATELLITE ALGORITHMS 62nd Interdepartmental Hurricane Conference, Charleston, SC, 3-7 March 2008 WESTERN NORTH PACIFIC TROPICAL CYCLONE STRUCTURE AND STRUCTURE CHANGE INCLUDING INTENSITY CHANGE AF C-130 STEPPED FREQUENCY MICROWAVE RADIOMETER (SFMR) AND DROPWINDSONDES AT ALL STAGES FROM FORMATION TO EXTRATROPICAL TRANSITION IN COOPERATION WITH T-PARC DOPPLER WIND LIDAR ON NRL P-3 VERTICAL PROFILES OF WIND VECTORS TO THE SURFACE (CROSS-CALIBRATION WITH C-130 SFMR) IN CLOUD-FREE SCENES – FIRST TIME IN TROPICAL CYCLONE COHERENT WIND STRUCTURES IN BOUNDARY LAYER OVER OCEAN IN TROPICAL CYCLONES (Emmitt and Foster)

U.S. FUNDING SOURCE INTERESTS AND REQUIREMENTS (TCS08-specific but affects other science objectives) 62nd Interdepartmental Hurricane Conference, Charleston, SC, 3-7 March 2008 Office of Naval Research (ONR) Air Force (AF) Naval Research Laboratory (NRL) National Science Foundation (NSF) PLATFORMSPONSOR% SCIENCE OBJECTIVES P-3 ELDORAONR/NRL50 Formation, Structure NSF50 Extratropical transition P-3 Wind LidarONR100All C-130 Flight hoursAF50 Satellite evaluation ONR/NRL50 Formation, Structure c- C-130 DropsondesAF100All Ocean buoysONR100 Structure (intensity)

Subtropical operating region Driftsonde, NRL P-3, DOTSTAR, WC-130 Japan, Yokota AFB Large-scale circulation, deep convection, monsoon depressions, tropical waves, TC formation TC track characteristics, tropical/midlatitude interaction ET characteristics, forcing of downstream impacts, tropical/midlatitude interactions, extratropical cyclogenesis Extratropical Transition (ET – recurvature), Downstream Impacts Tropical Measurements TC Intensification and structure change Recurvature, initiation of ET Okinawa, Kadena AFB Midlatitude operating region NRL P-3, FALCON T-PARC/TCS-08 Components Guam, Andersen AFB Tropical operating region Driftsonde, NRL P-3, DOTSTAR, WC-130 TY Nabi, 29 Aug – 8 Sep, 2005

Increase in forecast uncertainty over tropical and midlatitude regions often occurs due to tropical cyclones and the movement of tropical cyclones into the midlatitudes TY Tokage, October 2004 Tracks from the JMA ensemble prediction system Tracks supplied by Dr. T. Nakazawa What are the key structural aspects of the tropical cyclone and its environment that limit the predictability of recurvature and the start of extratropical transition over the subtropical western North Pacific? 62nd Interdepartmental Hurricane Conference, Charleston, SC, 3-7 March 2008