NASA Ames Research Center, Moffett Field, CANASA Ames Research Center, Moffett Field, CA HS3 Science & Deployment Preparation Meeting, 7-9 May, 2013 HS3 Science & Deployment Preparation Meeting, 7-9 May, 2013

A New TC Observing Strategy

Peter G. Black1,Jon Moskaitis2, James Doyle2, Chris Velden3 and Scott Braun4

(With special thanks to Michael Black, NOAA/AOML/HRD for sonde processing)

1Naval Research Laboratory and SAIC, Inc., Monterey, CA 2Naval Research Laboratory, Monterey, CA

3U. Wisconsin/ Cooperative Institute for Meteorological Satellite Studies, Madison, WI4NASA Goddard Space Flight Center, Greenbelt, MD

Analyses of hurricane outflow layer structure using dropsonde observations

deployed from a NASA Global Hawk AUVduring HS3

NASA Ames Research Center, Moffett Field, CANASA Ames Research Center, Moffett Field, CA HS3 Science & Deployment Preparation Meeting, 7-9 May, 2013 HS3 Science & Deployment Preparation Meeting, 7-9 May, 2013

A New TC Observing Strategy

Understand the coupling between the inflow and outflow branches of the secondary circulation (and the relationship of this coupling to intensity changes):

o Upper-level outflow changes lead to increased convection and intensification. Active Outflow Interaction of environment with TC

o Upper-level outflow changes result from increased convection/ low level forcing Passive Outflow Interaction of TC with environment

o Dependencies on boundary layer characteristicso Secondary eyewall cycles

Key Science Issue

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A New TC Observing StrategyUpper-Level Outflow

Background schematic courtesy of NASA

Low-Level Inflow

Secondary Circulation: IN, UP & OUT

Radar

SFMR

CPLHIRAD

HIWRAPGPS

Dropsonde

GPSSonde

Upper-Level Outflow

Strategy: 1) Global Hawks to observe the outflow layer and environment2) WC-130Js to observe the inflow layer structure and intensity

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A New TC Observing Strategy

15

10

5

0radius (nm)

Hei

gh

t (k

m) Outflow

300 600100

Air Force WC-130J:• SFMR: Surface winds/ intensity• Radar: Precipitation structure• AVAPS Dropsondes: Inflow layer vertical structure

SFMR

Radar

Global Hawk:• AV-1 remote sensors

HIRAD HIWRAP HAMSR?

• AV-6 Remote Sensors CPL S-HIS AVAPS DropsondesOutflow layer verticalstructure

Strategy: i) Global Hawks to observe the outflow layer and environmentii) WC-130J to observe inflow layer and inner-core intensity

Observational Strategy

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A New TC Observing Strategy

Lifecycle Hypothesis• Schematic of Outflow Channel Morphology from 7

case studies:- WPAC: Roke and Songda- ATL: Earl and Irene- GOM: Charlie, Katrina, and Opal

• Led to hypothesis relating TC outflow morphology changes to TC intensity changes:

HYPOTHESIS: There is a characteristic evolution of the outflow as the storm interacts with the environment that corresponds to changes in intensity and structure.

Phase I- TC development Phase II- RI

I. II. III.

Phase III- Mature & decay

NASA Ames Research Center, Moffett Field, CANASA Ames Research Center, Moffett Field, CA HS3 Science & Deployment Preparation Meeting, 7-9 May, 2013 HS3 Science & Deployment Preparation Meeting, 7-9 May, 2013

A New TC Observing Strategy

Leslie (7 Sept, 2012): Divergent outflow jets resulting from environmental interactionforce inner-core convection?

ACTIVE OUTFLOW

ORNadine (14-15 Sept, 2012):

Outflow forced by Supercell Convection?

PASSIVE OUTFLOW

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A New TC Observing Strategy

NASA HS3 Observations of Leslie and Nadine

Nadine: 11 Sep – 04 Oct 2012NASA HS3 Global Hawk Flight Tracks

• Nadine was the 5th longest-lived Atlantic hurricane on record.

• Nadine intensity varied from a 35 knot tropical storm to 80 knot hurricane.

• NASA HS3 Global Hawk deployed over 300 dropsondes during 5 flights in Nadine and 30 dropsondes in Leslie.

30 Drops

70 Drops

76 Drops

58 Drops

34 Drops

75 Drops

35 kts

65 kts70 kts 50 kts

55 kts

65 kts

80 kts

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A New TC Observing Strategy

Global Hawk Dropsonde Failure Rate- Nadine, 2012 No. reporting = 283

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A New TC Observing Strategy

Cross Section6 sondes

X

LeslieCenter

HS3 Observations of Leslie’s Outflow (150 mb)

20

40

60

80

Vm

ax

(kt)

Leslie CAT1

4 65 7 8Sept

9

CIMSS SATCON

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A New TC Observing Strategy

7 Sep 20121041-1111Z

HS3 Observations of Leslie’s Outflow

Black, Red, Blue and Pink lines:Global Hawk observedwind speed and temperature profilesalong jet maximum from dropsondes

Green line: COAMPS-TC modelwind speed profile

Red line: Satellite wind speed vertical average

Solid black: TropopauseDashed: Cirrus top / jet maxDotted: Cirrus cloud baseYellow shading: Cloud Physics

Lidar (CPL) domain

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A New TC Observing Strategy

South North

• HS3 dropsondes reveal unprecedented detail in depiction of outflow jet

• Sharp shear zone just above the sloping tropopause (~14 km) and below outflow jet

• Top of outflow jet coincident with top of cirrus deck from CPL

• Detailed cirrus fine structure suggestive of multiple turbulent mixing mechanisms

Total Wind Speed

Isotachs every 2.5 m/s

Tropopause

Cloud Physics LIDAR (CPL): Outflow layer cloud image

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A New TC Observing Strategy

5

10

15

20

25

30

CIMSS shear: 0-20 kt

SHIPS/CIRA shear: 0-50 kt

SHIPS/CIRA SST: 20-30 C

RSS MW-OI SST: 20-30 C

Nadine

GH

AV

-6 F

ligh

t

NASA Ames Research Center, Moffett Field, CANASA Ames Research Center, Moffett Field, CA HS3 Science & Deployment Preparation Meeting, 7-9 May, 2013 HS3 Science & Deployment Preparation Meeting, 7-9 May, 2013

A New TC Observing Strategy

• Outflow jet in Nadine, 14-15 Sept, sampled by multiple dropsondes (triangles- left) and Atmospheric Motion Vectors (AMVs- right).

• Outflow originates with active supercell west of center 13

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A New TC Observing Strategy

Outflow forced by SUPERCELL Convection:PASSIVE OUTFLOW?

OR:

Supercell forced by divergent outflowas a result ofenvironmentalinteraction:ACTIVE OUTFLOW

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A New TC Observing Strategy

o Double jet max below tropopause (dashed line)o Main jet max decreases in height, becomes stronger and thinner withincreasing radial distance.o Structures repeatable in 6 sondes along jet max.

Double wind max and constant wind layers are not observable with satellite AMVs over layer average(green dashed line) and may reflect physical processes not presently understood.

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A New TC Observing Strategy

Green is CIMSS mean upperwind at sonde location.

NASA Ames Research Center, Moffett Field, CANASA Ames Research Center, Moffett Field, CA HS3 Science & Deployment Preparation Meeting, 7-9 May, 2013 HS3 Science & Deployment Preparation Meeting, 7-9 May, 2013

A New TC Observing StrategyDramatic Upper-Level Outflow Change during Hurricane Sandy

o Jet streak associated with upper-level trough (thick blue arrow) approaches Sandy, creating expanded outflow structure (white arrows) toward the north and east.

o Intensity decreases slightly, but the size of the storm increases dramatically.

o Strong anticyclonic outflow displaced east of the center (pink dot): supports asymmetric deep convection.

Strong outflow displaced west and north, intensifying and expanding (jet max of 100–140 kt), with dramatic change forced by intensifying ridge northeast of Sandy (blue arrows) .

Sandy intensifies, further expands and accelerates just prior to landfall.

10/27/06z: Sandy intensity = 60 kt

10/29/12z: Sandy intensity = 80 kt

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A New TC Observing Strategy

Resulting Hurricane Sandy Landfall Impact

• Landfall of larger, more intense storm 12-hours earlier than expected.

• Devastating storm surge superimposed on high tide rather than weaker storm surge superimposed on low tide 12-hours later.

• Driven by Active Outfow?

NASA Ames Research Center, Moffett Field, CANASA Ames Research Center, Moffett Field, CA HS3 Science & Deployment Preparation Meeting, 7-9 May, 2013 HS3 Science & Deployment Preparation Meeting, 7-9 May, 2013

A New TC Observing Strategy

Recommendations and Future Plans

• Focus 2013-14 flight plans on more detailed dropsonde observation of outflow jet vertical structure (see following final slide).

• Obtain observation of magnitude and phasing of low-level mass inflow with respect upper mass outflow and jet structure evolution, i.e. secondary circulation development.

• Extend Global Hawk outflow layer studies to WPAC monsoon depression TCs and interaction with WPAC TUTT cells.

Key Results

• Fine scale outflow layer features and vertical outflow jet structures were recently observed in Hurricanes Leslie and Nadine (2012) by dropsondes deployed from high-altitude Global Hawk AUV

• They provide a new and more accurate representation of TC outflow layers that complement timeevolution provided by AMV’s only.

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A New TC Observing Strategy

Outflow Jet Fan pattern Outflow Jet Racetrack pattern