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
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)
62nd Interdepartmental Hurricane Conference, Charleston, SC, 3-7 March 2008
FORMATION: SCIENCE HYPOTHESES
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)
62nd Interdepartmental Hurricane Conference, Charleston, SC, 3-7 March 2008
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
62nd Interdepartmental Hurricane Conference, Charleston, SC, 3-7 March 2008
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)
62nd Interdepartmental Hurricane Conference, Charleston, SC, 3-7 March 2008
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
PGUM
Lawnmower
Pattern
Tropical Storm
WC-130J Survey:
1944 UTC 10 July 2007 BUTTERFLY
TMI 85 GhZ H
PA~300-700 mb,
IAS~280-240 kt
Targeting Option (280 kt transit)
Leg radii~110 nm
9.5 hr duration
Track 1.5 hr creep/day
GPS Dropsonde:
7 sondes per leg
+3 = 24 total
(eyewall multi-
PGUM sonde ~5 per leg
= +15; 39 total)
Butterfly Pattern AXBTs:
7 AXBTs per leg
Man Yi +2 diagonals x4
= 29 total
Typhoon WC-130J Survey
RODN 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
PGUM
0030 UTC 12 July 2007 Man Yi 0430 UTC 12 July 2007
amsre 89 GhZ H
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
62nd Interdepartmental Hurricane Conference, Charleston, SC, 3-7 March 2008
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)
62nd Interdepartmental Hurricane Conference, Charleston, SC, 3-7 March 2008
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 % SCIENCE
OBJECTIVES
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)
62nd Interdepartmental Hurricane Conference, Charleston, SC, 3-7 March 2008
TY Nabi, 29 Aug – 8 Sep, 2005
T-PARC/TCS-08 Components
Midlatitude operating region Extratropical Transition
NRL P-3, FALCON
(ET – recurvature),
Japan, Yokota AFB Downstream Impacts
ET characteristics, forcing
of downstream impacts,
tropical/midlatitude
interactions, extratropical
cyclogenesis
Subtropical operating region
Driftsonde, NRL P-3,
DOTSTAR, WC-130 TC Intensification
TC track characteristics, and structure
tropical/midlatitude
interaction change
Recurvature, initiation of
Tropical operating region ET
Driftsonde, NRL P-3,
Okinawa, DOTSTAR, WC-130 Tropical Measurements
Kadena AFB
Large-scale circulation,
deep convection,
monsoon depressions,
Guam, Andersen AFB tropical waves,
TC formation
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?
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
62nd Interdepartmental Hurricane Conference, Charleston, SC, 3-7 March 2008