TROPICAL CYCLONE STRUCTURE (TCS08) FIELD EXPERIMENT IN THE WESTERN NORTH PACIFIC DURING 2008 Russell...

TROPICAL CYCLONE STRUCTURE (TCS08) FIELD EXPERIMENTIN 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)

SPONSORSOffice of Naval Research

Naval Research LaboratoryAir Force*

National Science Foundation

* With thanks to LCOL Kurt Brueske

62nd 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)


FORMATION: SCIENCE HYPOTHESES


Science hypothesesMesoscale 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 operationsGlobal model forecasts for potential cloud clustersRegional model forecasts for likely mesoscale organizationSatellite (geostationary and polar-orbiting for continual monitoring, cross-checking against model output, and aircraft briefing and in-flight support)

STRUCTURE: SCIENCE HYPOTHESES


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


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 convectionDoppler Wind Lidar for inflow measurements

Use of WC-130 to measure the environmental characteristics

BASE OF OPERATIONS AT ANDERSEN AFB, GUAM


Pre-PabukTropical Wave

LawnmowerPattern

PGUM

Man Yi

Tropical Storm WC-130J Survey:BUTTERFLY

PA~300-700 mb, IAS~280-240 kt(280 kt transit)Leg radii~110 nm9.5 hr duration1.5 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 2007TMI 85 GhZ H

PGUM

Track

Targeting Option

Butterfly Pattern

0030 UTC 12 July 2007 0430 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 duration7 sondes per profile x 4 = 28 total(eyewall multi-sonde: +5 per profilex 2 = +10 = 38 total; or x 4 = +20 = 48 total); no creep7 AXBTs per profile x 4 = 28 total

Man Yi

SPECIAL TCS08 RESOURCES


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


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-3VERTICAL 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)


Office of Naval Research (ONR) Air Force (AF) Naval Research Laboratory (NRL) National Science Foundation (NSF)

PLATFORM SPONSOR % SCIENCEOBJECTIVES

P-3 ELDORA ONR/NRL 50 Formation, Structure

NSF 50 Extratropical transition

P-3 Wind Lidar ONR 100 All C-130 Flight hours AF 50 Satellite evaluation

ONR/NRL 50 Formation, Structure c-C-130 Dropsondes AF 100 All Ocean buoys ONR 100 Structure (intensity)

Subtropical operating regionDriftsonde, 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 changeRecurvature, initiation of ET

Okinawa, Kadena AFB

Midlatitude operating regionNRL P-3, FALCON

T-PARC/TCS-08 Components

Guam, Andersen AFB

Tropical operating regionDriftsonde, 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 2004Tracks 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?


TROPICAL CYCLONE STRUCTURE (TCS08) FIELD EXPERIMENT IN THE WESTERN NORTH PACIFIC DURING 2008 Russell...

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