Tropical Cyclone Reconnaissance with the Global Hawk: Opera9onal Requirements, Benefits, and Feasibility

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1 Tropical Cyclone Reconnaissance with the Global Hawk: Opera9onal Requirements, Benefits, and Feasibility Patrick Harr, Department of Meteorology, Naval Postgraduate School NASA Global Hawk flight tracks over Hurricane Nadine in September 2012

2 Uncertainty in forecasts of tropical cyclone tracks Defined by ensemble prediction systems at global operational weather centers Represents the chaotic nature of the atmosphere and sensitivity to initial conditions ECMWF/UKMO Ensemble track predictions for TY Sinlaku in 2008 Forecasts obtained from the THORPEX Interactive Global Grand Ensemble (TIGGE) database

3 Western Pacific: Active Area of Maneuverability 1.4M sq miles of area lost to error swath at 72 hours. A 50% reduction in error would add up to 21M sq miles of sea maneuver per year. Current uncertainty Desired uncertainty PACOM Goal: Increase US/Coalition Sea Maneuver Space Naval Oceanography

4 JTWC TRACK ERRORS (Western North Pacific Hours) Annual errors are at all time low values But 5 yr averages are not decreasing Naval Oceanography

5 JTWC TRACK ERRORS (Western North Pacific Hours) Annual errors are at Trends in forecast accuracy: all time low values Natural variability certain tracks may be But 5 yr averages are not decreasing more difficult to predict Availability of data to assess initial conditions Storm structure o Remote sensing data o In situ data Large-scale environment Limits to predictability Naval Oceanography

6 Extratropical Downstream Impacts TC structure change, track uncertainty Recurvature, ini9a9on of ET Large- scale circula9on, deep convec9on, monsoon depressions, tropical waves, TC forma9on

7 Simultaneous observations of TY-core, TY-environment and distant sensitive region associated with TY Sinlaku Joint mission of: Falcon (yellow) C-130 (black) DOTSTAR (red) Inner core Immediate vicinity Remote sensitivity region From M. Weissmann

8 Weissmann et al. Mon. Wea. Rev Differences in 72- h DROP and NODROP track forecast errors Sinlaku Forecast degrada@on arer recurvature Incorpora@on of aircrar observa@ons improve forecasts prior to recurvature The tropical regions are rela@vely data- void compared to midla@tude regions over which the storm moves following recurvature Forecasts that are very accurate without aircrar data are degraded by the use of aircrar data

9 Western North Pacific Tropical Cyclone Reconnaissance: Andersen AB, Guam Andersen AFB, Guam

10 Current NASA Global Hawk Instrument Design

11 Global Hawk Dropwindsondes Basic sensor that provides numerous profiles of the typhoon environment Intended to improve weather models used to forecast TC and intensity

12 Remote Sensing Instrumenta9on Measures hurricane surface wind speeds and rain rates over a wideswath: Swath Width ~ 80 km Resolution ~ 1-5 km Wind speed ~10 85 m/s Rain rate ~ mm/hr Key Feature: Near-instantaneous mapping of entire inner-core hurricane surface wind field and rain structure. Operational advantages: Surface wind and rain swath will complement SFMR and airborne Doppler radar mapping of innercore structure for improved shortterm advisories and numerical model initialization. HIRAD Swath Geometry NASA HS3 Global Hawk configura9on for

13 Tropical Cyclone Structure Environmental are oren concentrated in the ouvlow layer, which is above 45,000 feet. Upper Level OuSlow

14 WPAC Global Hawk Demo: concept of operations Height (km) Radar Outflow Air Force WC-130J SFMR: Surface winds / intensity Radar: Precipitation structure Flight level instruments SFMR Global Hawks Suite of remote sensing Ø Environmental Ø Over-Storm Dropsondes Ø YES sondes radius (nm)

15 Some numbers: Global Hawk tropical cyclone reconnaissance 2 months of from Andersen AB, Guam Workshop 6-8 November to coordinate USAF, USN, and NOAA