Tropical Cyclone Structure I: Tropical Cyclone Formation II: Tropical Cyclone Intensification III: Tropical Cyclone Structure Change Acknowledgments: Office of Naval Research, Marine Meteorology National Science Foundation, Large-Scale Dynamics USAF, 13 th AF

Tropical cyclone formation, structure and structure change: Challenges to Maritime Operations Variety of conditions from which a tropical cyclone may form over the western North Pacific Warning graphics from the Joint Typhoon Warning Center for TY Tokage. The shaded region defines the danger area to be avoided. This area is based on the uncertainty associated with track and outer wind structure over the ensuing five days. Note: The danger area nearly covers the entire East China Sea for a period of at least 5 days. The change in track forecast from straight to recurvature, which may be due to the influence of the outer wind structure Pre-TY Tokage monsoon depressionTY Tokage 0000 UTC 14 October 2004 TY Tokage: 0000 UTC 14 October 2004TY Tokage: 1200 UTC 15 October 2004

Midget tropical cyclones often develop in narrow zone along the periphery of a monsoon gyre or in association with an upper-level trough For this small tropical cyclone, the danger area is only 4 deg. in diameter and there is no change in track TS Danas (11W) 1200 UTC 8 Sep 2007 TS Danas (11W) Danger area graphic 0000 UTC 9 Sep 2007 Tropical cyclone formation, structure and structure change: Challenges to Maritime Operations

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 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)

How does the large-scale atmosphere and ocean environment control the mesoscale environment prior to tropical cyclone formation? Objective: medium-range predictability of the tropical large-scale environmental factors that influence tropical cyclone formation Large-scale modes of variability Shading represents positive (light) and negative (dark) OLR anomalies. Streamlines represent anomalous flow patterns at 850 hPa. The pattern to the left leads the pattern on the right by an average of 10 days.

What are the relative roles of the primary mesoscale mechanisms (bottom-up and top-down) in determining the location, timing, and rate of tropical cyclone formation in the monsoon trough environment of the tropical western North Pacific? Pre-Fitow (10W 2007) disturbance Pre-Man-Yi (04W 2007) disturbance Objective: Increased predictability associated with the location, timing, and rate of tropical cyclone formation over the western North Pacific 19 o 10 o

What are the relative roles of environmentally-induced and vortex- generated mechanisms versus cyclogenesis-determined initial conditions in determining the outer wind structural evolution of western North Pacific tropical cyclones? Objective: Increased understanding and predictability of factors that impact the evolution of the outer-wind structure of an intensifying tropical cyclone over the western North Pacific. Mesoscale Forcing Synoptic Forcing Mesoscale type: Small Tropical Cyclones Combination type Large and Small Tropical Cyclones Synoptic Type: Large Tropical Cyclones

North NW TMI 85H Z NOAA Z 10,000’ Satellite – Aircraft Comparisons Hurricane Rita Graphic supplied by J. Hawkins

VALIDATION OF SATELLITE ALGORITHMS 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)

Observing Platforms (1 August – 30 September) NRL P-3/ NCAR ELDORA/ DWL lidar/ GPS Dropwindsondes 50/50 funding split between NSF and ONR Operation from Andersen AFB, Guam, Kadena AFB, Okinawa, Atsugi NAF, Misawa NAF Japan Total of 150 research hours 450 dropwindsondes (30 sondes per mission) USAF Reserve 53rd Weather Squadron (Hurricane Hunter) WC-130J Funding from ONR and USAF Operation from Andersen AFB, Guam, Kadena AFB, Okinawa, Yokota AFB, Japan Dropwindsondes Stepped Frequency Microwave Radiometer AXBTs, Drifting Buoys Other Components DOTSTAR Driftsondes –Launch from Hawaii –20 balloons with dropwindsonde gondolas –40 dropwindsondes per gondola Satellite: MTSAT rapid scan, Polar orbiting platforms

Combined missions during tropical cyclone formation Use of Eldora to measure characteristics associated with deep convection Use of WC-130 to measure the environmental characteristics Pre- TY 10W (Fitow) Disturbance

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

Summary Much recent national and international attention on TCs Four Major Weather Forecast Problems in the Pacific Lack of understanding of storm scale processes is the biggest knowledge gap (basic research common to all four) Proposing: –First major WESTPAC field experiment since TCM93 –First detailed observations of TC outer winds, genesis & life-cycle (in situ aircraft, radar, dropsondes, lidar, remote sensing) –First measurements. to validate new and advanced satellite obs. of WP TCs –Utilize the post-CBLAST coupled ocean-wave-atmosphere modeling system as a testbed to gain understanding of the processes as informed and constrained by the field data Expected accomplishments: –Increase the predictability of the environmental forcing, formation, outer wind structure and intensity of TCs over the western North Pacific –Leverage several international efforts –GOAL: to reduce errors in TC structure and intensity forecasts by 50% within a decade –will also increase warning times and improve ocean and wave forecasts