U.S. Contribution to T-NAWDEX: “DOWNSTREAM” Heather Archambault (NPS), Steven Cavallo (OU), Dan...
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Transcript of U.S. Contribution to T-NAWDEX: “DOWNSTREAM” Heather Archambault (NPS), Steven Cavallo (OU), Dan...
U.S. Contribution to T-NAWDEX:
“DOWNSTREAM”
Heather Archambault (NPS), Steven Cavallo (OU), Dan Cziczo (MIT), Chris Davis (NCAR), Pat Harr (NPS),
Laura Pan (NCAR), Mark Zondlo (Princeton)
T-NAWDEX WorkshopKarlsruhe, Germany
20 March 2013
“DOWNSTREAM”
Dynamics and Observations of the Waveguide: North–South Transport
and Rossby wave Excitation over Atlantic Midlatitudes
Synergy with T-NAWDEX
• Focused over eastern North America and the western North Atlantic
• Scientific foci:– Stratospheric–tropospheric exchange– Tropical, midlatitude, and polar forcing of
waveguide perturbations – Predictability– Multiscale interactions
Waveguide forcing
PV distribution
“DOWNSTREAM” Science Themes
Synoptic-to-hemispheric scaleRossby wave amplification, dispersion, breaking along North Atlantic
waveguide, tropospheric–stratospheric exchange (water vapor)
Meso-to-sub-synoptic scaleTropopause polar vortices, transitioning tropical cyclones, warm conveyor belts, diabatic Rossby vortices, predecessor rain events
MicroscaleClouds, aerosols, trace constituents, radiation, turbulence
Impacts on medium-range predictability
1. Science Questions Related to Extratropical Transition
Midlatitude impactregion
TC–midlatitudeinterface region
Decaying tropical cyclone core region
• How do sub-synoptic-scale phenomena generate waveguide perturbations?
• What is relative contribution of diabatic heating in frontal zones versus tropical cyclone (TC) core?
• Is TC outflow the primary means of perturbing the waveguide?
• What is the detailed vertical structure of:• TC outflow?• merger of TC outflow and midlatitude jet?•
1. Science Questions Related to Extratropical Transition
Grams et al., 2013: QJRMS
“No radiation” minus “with radiation”
In composite numerical simulated vortices, a weaker TPV occurs without radiation
• Formation and extrusion of tropopause polar vortices (TPV) and sensitivities to diabatic (e.g., radiation) variations:
• How well are these represented?
• How do clouds influence process?
• How do these coherent structures evolve as they approach the jet?
• What happens to the jet itself?
2. Science Questions Related to Polar Vortices
Cavallo and Hakim, 2012: MWR
8 Sep 2012 9 Sep 2012 10 Sep 2012 11 Sep 2012
Potential temperature on 2-PVU surface (0000 UTC) (ET of Leslie)
3. Science Questions Related to Predictability
How do multiple sources of waveguide perturbations influence predictability on synoptic to hemispheric scales?
250-hPa v’
30
31
01
02
03
04
05
06
07
08
09
X
OCT
NOV
30
31
01
02
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09120°E 180° 120°W 60°W 0°
+1.0 +1.5 +2.0 +2.5-1.0-1.5-2.0-2.5
NASAOUTFLOW
DOWNSTREAMT-NAWDEX
Flooding rain
4. Science Questions Related to UTLS Transport of Water and Other Constituents
Figure 1 from Pan et al., 2008: BAMS (adapted from Stohl et al. 2003 : (BAMS)
• How are water vapor and other constituents transported into the lower stratosphere in outflow (WCB) regions associated with extratropical and tropical cyclones?
• What are the source regions?
5. Science Questions Related to Cirrus Clouds• What drives the spatial variability of ice, H2O, T, and w on scales of
0.2–20 km?
• How do water and temperature define the spatial distribution of relative humidity?
• How can tracer correlations be used to understand larger-scale dynamics?
5. Science Questions Related to Cirrus Clouds• What are the mechanisms yielding ice supersaturated regions for
cirrus formation?
• How does cirrus formation differ as aerosol characteristics change?
• How do cirrus clouds affect the overall budget of water vapor in the upper troposphere/lower stratosphere region?
Extratropical transition of TC Leslie 0000 UTC 10 Sep 2012
96Cirrus shield extends far downstream of TC
G-V Flight Range
IR satellite
A Candidate DOWNSTREAM Case
Potential temperature on dynamic tropopause
A Candidate DOWNSTREAM Case
Extratropical transition of TC Leslie 0000 UTC 10 Sep 2012
Potential temperature on dynamic tropopause
TC Outflow Layer
Instrumentation and Uses• W-band cloud radar (Doppler)• Ka Band radar (?)• VCSEL – water vapor• Microwave Temperature Profiler (MTP)• Dropsondes• CVI (Counterflow Virtual Impactor)• Fast Ozone• CO• Various trace species
MTP? HCR?
GV Cloud Radar:15°–20° scan
If variation in ‘x’ is slow compared to variation in ‘y’:
• MTP can obtain gradients of potential temperature within “curtain” along flight track
• Cloud radar can obtain velocities below aircraft
• PV estimates with a resolution of <10 km horizontal, roughly 200 m vertical
x
y
Approximate form, if slowly varying along the jet relative to across jet
PV Estimation from MTP Data
Jet Stream
z
NRC (Canadian) Convair-580 The National Research Council (NRC) of Canada operates a twin-
turboprop Convair-580 research aircraft. Operation is on a full cost-recovery basis, so full funding is required even
for government-backed projects.
Service ceiling: 7200 m (23,500 ft)Cruising speed at altitude: ~215 ktRange Out-and-back: 1000 km
One-way: 2000 kmAircrew: 2 peopleResearch crew: ~12 peopleHome page: www.nawx.nrc.gc.ca
The Convair-580 is used heavily for microphysical measurements, particularly for projects related aircraft icing and air quality
Can carry a range of remote sensing equipment: W- and X-band radars (up, down, side views) and a G-band water vapour radiometer
Bulk cloud parameters EC Cloud Extinction Probe (CEP)
Cloud particles SPEC Cloud Particle Imager (CPI), SPEC 2D-S (10-1280um)
NRC (Canadian) Convair-580 The Convair-580 flew into hurricanes Michael (2000), Karen (2000) and
Isabel (2003) during extratropical transition (ET). The Isabel mission was the first to sample an ET with flight level sensors
and dropsondes over land.
(Above) Equipment installed during flight into Hurricane Michael (2000). (Right) Storm track and near-surface winds from dropsondes, and radar cross-section wind dropsonde winds. All panels from adapted from Abraham et al. (BAMS, 2004).
NRC (Canadian) Convair-580 The Convair-580 could be booked for a 2-month period (i.e. Sept-Oct
2016), but deployed only when a feature of interest is predicted. If based in St. John's, Newfoundland, the Convair could be ready for
operation (i.e. ferried from Ottawa) with 3-days notice: may be more consistent with more predictable features.
All previous flights into storms undergoing ET have been round-trip
To extend coverage to 40oN, 40oW (or slightly further south) the Convair could land to refuel in the Azores; however, crew rest requirements probably mean an overnight before the return flight
40oW
Azores
Range rings for Convair-580 based in St. John's, Newfoundland. Red ring is for a round-trip flight, magenta ring is for a one-way flight.
Summary
• DOWNSTREAM: Sept-Oct. 2016• Eastern U.S., Canada and Northwest Atlantic• Dynamics-driven study of origin of waveguide perturbations• Transport and small-scale cloud processes• Effects on PV distribution• Predictability associated with mesoscale features• NSF-NCAR GV aircraft: unique collaborative opportunity with
two G-Vs.