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Hurricane outflow structures observed during HS3 2012-13 from AV-6 dropsondes and CIMSS Atmospheric Motion Vectors. Peter G. Black 1 , James D. Doyle 2 , Jon Moskaitis 2 , Scott Braun 3 and Chris Velden 4 1 SAIC, Inc ./ Naval Research Laboratory, Monterey, CA
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Hurricane outflow structures observed during HS3 2012-13 from AV-6 dropsondesand CIMSS Atmospheric Motion Vectors Peter G. Black1, James D. Doyle2, Jon Moskaitis2, Scott Braun3 and Chris Velden4 1SAIC, Inc./ Naval Research Laboratory, Monterey, CA 2Naval Research Laboratory, Monterey, CA 3NASA Goddard Spaceflight Center, Greenbelt, MD 4Cooperative Institute for Meteorological Satellite Studies, University of Wisconsin, Madison, WI
Objective Establish the pattern of outflow layer jet features with which hurricane structure and intensity change may be associated. Approach Utilize in-situ, new-generation atmospheric profiling dropsondes (AVAPS minisonde, HDSS/XDD-2014) and state-of-the-art remote sensors flown on Global Hawk UAVs and reconditioned WB-57 aircraft, in concert with satellite-derived Atmospheric Motion Vectors (AMVs), to directly observe hurricane outflow layer features.
HYPOTHESIS TC Life Cycle, including Rapid Intensification (RI), is associated with environmentally-forced outflow jet evolution: TC development- Single Equatorward-directed Jet Intensification and RI: Dual Equatorward and Poleward Jets Mature & decay: Primarily, single Poleward-directed Jet
Storm Intensity Leslie, 2012 Nadine, 2012
Leslie Outflow Jet Leslie
Leslie Cloud Physics Lidar
Nadine Outflow Jet Nadine Nadine
Pre-Gabrielle (30 kt), 2013 04/ 1930Z – 05/ 1017Z 0240-0435Z, 2240-0035L 4 Sept 18Z, 14L 5 Sept 00Z, 20L 200 mb • Single environmental, poleward-directed outflow jet develops during GH legs 3-hr after center passage. • Thick outflow jet typical of inner-core develops with multiple constant-wind shear layers • Intense convective development south of P.R., 100 km east of surface, after GH sampling- from WC-130J, NWS 88D Radar. 5 Sept 06Z, 02L 925 mb
Convective Development ACHA vs SJU Radar 04/2130Z 05/0000Z 05/0600Z 04/1730L 05/0330Z 05/0600Z 05/0330Z 05/0000Z 04/2130Z 05/0600Z 05/0900Z 05/1200Z 05/1500Z Pre-Gabrielle 2013
AMV Diurnal Outflow Pattern Pre- Gabrielle 2013 4 Sept 21Z, 17L 4 Sept 18Z, 14L 5 Sept 06Z, 02L 5 Sept 09Z, 05L 5 Sept 03Z, 4/23L 5 Sept 00Z, 4/20L 5 Sept 12Z, 08L 5 Sept 15Z, 11L 5 Sept 18Z, 14L
TC Diurnal Cycle (2001-2010: 31 Major Hurricanes) Courtesy: Jason Dunion • Key Features from Major Hurricanes • TCs have a clear diurnal cycle in IR Brightness Temperature (TB) • The TC diurnal cycle has the form of a pulse with coldest TB originating near the inner core at midnight, propagating outward to the 600 km radius by evening (1800-2100 LST) • Upper outflow jets appear to exhibit a strong diurnal pulse.
Outflow Layer Analysis • Achievements and Key Findings • Three TC outflow layers sampled 2012-13: Leslie, Nadine, Pre-Gabrielle. • Outflow layer jets appear to precede intense inner core convection • Thin peripheral outflow jets are forced by environmental features: Leslie • Subtropical jets • Upper cold lows • Tropical Upper Tropospheric Troughs (TUTTs) • Thick inner-core outflow jets associated with convective bursts: Nadine and Pre-Gabriel • Here-to-for unknown outflow jet fine-structure may lead to instabilities which enhance outflow layer mixing not yet adequately modelled. • Outflow jets appear to have diurnal modulation.