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This overview discusses the WC-130J aircraft's performance and observational strategies during the TPARC/TCS08 experiment, focusing on the vertical structure of tropical cyclones and their intensity change. It also examines the hypotheses related to typhoon formation and rapid intensity change and presents preliminary results.
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Overview of WC-130J storm-scale observations during TPARC/TCS08 Peter G. Black (1) and Jeffrey D. Hawkins (2) (1) SAIC, Inc. and Naval Research Laboratory, Monterey, CA (2) Naval Research Laboratory, Monterey, CA Third THORPEX International Science Symposium Monterey, CA 14-18 September, 2009
TCS08 Experiment Analysis: Tools What did we use? • WC-130J Aircraft (2) • GPS dropsonde (750, ~ 26/flt) for • atmospheric profiling (high-altitude) • AXBT*- ocean thermal profiling (250, ~ 13/flt) • SFMR- surface winds • Radar Video Recording*- TC structure • ADOS profiler/ Minimet drift buoys- 3D ocean structure, surface currents (24) • NRL P3 (1) • Eldora Doppler Radar- 3D winds • LIDAR*- boundary layer wind profiles • GPS dropsonde- atmospheric profiling (low) • *First used in TCS08
TCS08 Experimental Analysis: Statistics WC-130J Aircraft Performance • Research Flights • Missions: 26 • Mission Flight Hours: 263 • High-Level Missions, 300mb: 12 • TC 700mb Missions: 12 • Buoy Deployment Missions: 2 • Tropical Cyclones: 4
TC Observational Strategy • Define vertical structure over a TC vortex-scale domain (WC-130J) in developing/intensifying systems within environmental domain (SAT, DOTSTAR, FALCON) to provide context for mesovortex (VHT) domain (P3) • Focus on better definition of asymmetric 3D initial vortex in sheared environment for evolving coupled models • Driven by emerging requirements for improved 5 to 7 day forecasts
TCS08 Experiment Analysis:Situational Awareness Real-Time Data Fusion Real-Time Communications
TCS08 Experiment Analysis:HYPOTHESES I First of Two Key Hypotheses: • Typhoon Formation emerges from initial • meso-vortex in Convective Cloud Clusters via: • Mid-level spin-up and downward growth, i.e.- • Top-Down • OR • Low-level spin-up and upward growth, i.e.- • Bottom-Up
TCS08 Experiment Analysis: Scenarios Two of several Key Formation Scenarios: • Tropical Easterly Wave/ Upper Trough Interactions: (Many observed during TCS08) • Westerly Wind Burst associated with • monsoon trough: (NONE observed during TCS08)
TCS08 Experiment Analysis: RATIONALE I Why Investigate TC Formation? • New 5-day forecasts (soon 7-day forecasts) • require improved knowledge of TC Formation: • Where? • How Fast? • Strategic and economic consequences • increasing exponentially with time!
TCS08 Experiment Analysis: OBJECTIVE I • Address Hypothesis I: Develop • high-level WC-130J Aircraft observing • strategy to define: • TC 3D storm-scale structure • Intensity Change • Context for NRL P3 meso-scale obs
TCS08 Experiment Analysis: RESULTS I (Preliminary) • Hypothesis I: Concurrent low- and mid-level • vortices were observed in developing and • non-developing TC Formation cases • with 120 – 200 km separation (In Tropical • Wave/ TUTT interaction cases), i.e. not single • tilted vortex, but distinct vortex pairs Challengeis to learn to distinguish developers from non-developers
TCS-25 27-28, Aug Surface TCS-25 27-28, Aug 700 mb Surface 120 km 700 mb 15 kt 20 kt x x 20 kt 15 kt
SSMIS- F16 27 Sept, 2213 GMT WC-130J sondes- SFC 27 Sept, 21 UTC - 28 Sept, 03 UTC x
TCS-37 Surface 15 kt 15 kt 200 km separation TCS-37 400 MB 25 kt 25 kt
Data Fusion: Google-Earth Enhanced IR + WC-130J flight track, Dropsonde locations Active convection At begining of flight 0330 UTC 7 Sept, 2008 Convection collapses near end of flight TCS-37 0030 UTC 7 Sept, 2008
TCS08 Experiment Analysis: HYPOTHESES II Second of Two Key Hypotheses: • II. Typhoon Intensity Change, including Rapid • Intensification (RI), is driven by atmospheric • conditioning: • Large-scale environmental interaction • Oceanic Variability
TCS08 Experiment Analysis: RATIONALE II Why Investigate TC Rapid Intensity (RI) Change? • Rapid Intensity (RI) Change accounts • for more than half of the large TC intensity • forecast errors. • Strategic and economic consequences • for unforecasted RI, which occur in only • 15% of the TC life cycle, account for 85% • of TC losses.
TCS08 Experiment Analysis: OBJECTIVE II • Address Hypothesis II: Develop TC • and ocean observing strategy to define • background ocean conditions and • ocean-TC interaction • (Environmental monitoring accomplished by TPARC • large-scale observing strategy)
TCS08 Experiment Analysis: RESULTS II (Preliminary) • Hypothesis II: Rapid TC Intensification • and Rapid TC Filling occurred over Warm • and Cold eddies, respectively, in the WPAC • Southern Eddy Zone* • Defined by Wu, et al. (18-25N)
TCS08 Jangmi Sept, 2008 Track, Intensity Change JMA Aircraft Pmin Aircraft 1000 OHC Gradient 150 980 Landfall Rapid Intensification Wind Speed (kt) Pressure (mb) 100 960 Rapid Filling Kuroshio SATCON Intensity: Velden, CIMSS Hawkins, NRL 940 50 920 Rapid Structure Change 900 0 9/23 9/24 9/25 9/26 9/27 9/28 9/29 9/30 10/1 10/2
Eyewall open west, NW quad rainbands disappear Rapid Structure Change STY Jangmi 27 Sept, 0445 Time Concentric Eyewalls: Peak Intensity SSTA 27 Sept, 2132 Eyewall, bands decay 27 Sept, 1134 28 Sept, 0006 Eyewall shrinks, asymmetric band structure forms Cold, Shallow OHC Gradient Warm, Deep
Jangmi OHC 27 Aug Jangmi SSTA 2008 26 Aug Jangmi SSTA 2008 28 Aug
QSCAT- and ASCAT-only Data over-estimates size And under-estimates intensity WC-130J SFMR data defines true TC intensity and size
Super-Typhoon Jangmi Radar Video defines Eyewall and Rainband Structure and Evolution 27 Sept., 2008 0935 UTC
Aircraft – Buoy Deployment First occurrence of the deployment of drifting buoys ahead of a category 5 tropical cyclone (Jangmi). Chart at left and imagery below are from a few hours after the deployment of the buoys along the diagonal to the northwest of the TC 2313 UTC 26 September First buoy deployment In TY Hagupit several days earlier P-3 flight track Second deployment in STY Jangmi Buoy, aircraft, and satellite data in Google Earth
TCS08 Ocean Heat • Content Obs: • Concurrent with GPS dropsondes • Preview of ITOP2010 AXBT vs NRL Ocean Model Initial Conditions Ocean Heat Content (OHC) Model underpredicts high heat content TCS08 AXBT Locations Ko, NRL Stennis
Data Gap Data Gap AXBT’s act to fill data gaps in drifter coverage And define spacial gradients
2008 Drifters 25 Aug 27 Aug 29 Aug
50 m 100 m D26 AXBT’s help to adjust model-predicted eddy locations Ko, NRL Stennis
FINAL COMMENT • We are at an historic turning point in history for improving hurricane intensity observation and forecasting where the capability to observe the TC surface and mid-level wind domain concurrent with subsurface ocean thermal structure matches the improved coupled model capabilities to assimilate and model the total TC environment. • This alignment should provide the next best opportunity for improving hurricane intensity and structure forecasting.
CONCLUSIONS • ‘Tip-of-the-iceberg’ Results: • Co-existence of low/mid level vortex pairs is typical of formation events • Strong relation of RI/RF to warm/cold ocean eddies in absence of strong • atmospheric forcing • The observation strategy for TCS08 was sound • ‘Stage is set’ for additional in-depth analysis • Determine system evolution with time • Validate satellite estimation schemes • Elaborate theoretical hypotheses leading to new physics • Conduct coupled numerical model simulations to test new physics • For the Future- Fill GAPS (possibly in concert with ITOP 2010) by observing: • Normally-dominant monsoon trough/ westerly burst formation events • Vortex-pair TC formation scenarios • Satellite validation cases to reach statistical significance • Air-sea RI events with and without strong shear for small/large TCs
Overview of WC-130J storm-scale observations during TPARC/TCS08 AUXILLARY SLIDES Peter G. Black (1) and Jeffrey D. Hawkins (2) (1) SAIC, Inc. and Naval Research Laboratory, Monterey, CA (2) Naval Research Laboratory, Monterey, CA Third THORPEX International Science Symposium Monterey, CA 14-18 September, 2009
TCS08 Experiment Analysis: Milestones What did we do? • Developed detailed flight plan and communications strategies • Developed and implemented AXBT observing system and implemented drift buoy deployments • Implemented high altitude (300 mb) TC formation flight strategy with concurrent GPS sonde and AXBT deployments over a 5 deg grid • Provided maximum surface wind and minimum surface pressure observations during TC life cycle for validation of satellite TC Intensity estimates (Hawkins, et al) • Provided aircraft SFMR, radar video, AXBT and GPS dropsonde data for initialization/validation of COAMPS-TC coupled model simulations of STYJangmi and other TCS08 typhoons (Doyle, et al)
Zig-Zag Square Spiral Racetrack Bow-Tie TCS08 Flight Patterns: Formation Base of Operations Define multi-level vortex and cloud cluster evolution Most frequently used
Rotated Fig 4 Butterfly Bow-Tie Figure 4 TCS08 Flight Patterns: TC Structure Base of Operations Define mean vortex Observe Pmin, Vmax Define structure, TC asymmetries