The T-REX experiment
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Transcript of The T-REX experiment
The T-REX experimentRalph Burton1, Stephen Mobbs1, Barbara Brooks1
Harold Klieforth2, Martin Hill1
1 IAS 2 Desert Research Institute, Reno NV
1. Motivation.
2. Rotors: brief overview.
3. T-REX.
From
“Hazardous Mountain Windsand their Visual Indicators”Federal Aviation Authority,
U.S.Dept. of Transportation, 1988
• Accidents not limited to one operating altitude, or time of year, or specific type of aircraft
• In many cases, other aircraft operating in thevicinity of the accident encountered only weakturbulence severe wind events can be highly
localised, violent, andshort-lived
From “Hazardous Mountain
Windsand their
Visual Indicators”,
1988
Accident rate less than 3 per 100,000Accident rate greater than 3 per 100,000
Accident rate 40% higher in the 11 mountainstates
DEM of the U.S. showing regionsof elevated terrain
http://adds.aviationweather.gov
From
From http://adds.aviationweather.gov
For aviation weather reports,see
http://adds.aviationweather.gov
Extensive mountain
obscuration
Owens (dry) lake
• Probably the largest single source of PM10 dust in the United States
• Dust plumes tracked to 3000m AGL, 100 km north of the lake
• Affects visibility and vegetation in many neighbouring wilderness areas
• Dust storms regularly cause suspension of operations at China Lake Naval Weapons Center
See geochange.er.usgs.gov/sw/impacts/geology/owens
From Reheis (1997)
Looking South from 9800m/32000ft
W
I
Sierra wave Project (1950s)
Sierra WaveProject (1950s)
Flight of Feb. 16th 1952
From Holmboeand Klieforth 1957
A: Type 1 rotor
B: Type 2 rotor
From Kuettner (1959)
Maximum rates of climb
Cessna 172: 720 ft/min
Ibis aerospace 270: 1791 ft/min
Boeing Chinook: 1840 ft/min
Sierra WaveProject (1950s)
Flight of Feb. 16th 1952
From Holmboeand Klieforth 1957
W=-31ft/s
w=+41ft/s
Maximum rates of climb
Cessna 172: 720 ft/min
Ibis aerospace 270: 1791 ft/min
Boeing Chinook: 1840 ft/min
Rotor: -1860ft/min
Net downward
Net downward
Net downward
“Type 1”rotor
“Type 2”rotor
“Inversion effects onmountain lee waves”
Vosper, QJR 2003
Inversion height
Wind constant with height
Regime diagram
H = hill heightzi = inversion height;
Fi = U/(g’zi)1/2
g’ = g/0
U = background wind
BLASIUS;idealised ridge
H/Zi > 0.3
Consider u=10 ms-1
surf temp = 200C,Zi = 3600m,
then we have
U2 ~ 45
gives ~ 2K
Climatologyof wave events
Based upon satellite imagery,1km resolution,15 minute intervals(visible channel)
From Grubišić,T-REX proposal
Oct 29th 2000
From Doyle and Durran (2004)
GOES -Vis
Regime diagram
“Inversion effects onmountain lee waves”
Vosper, QJR 2003
29/10/2000
Doyle and Durran (2004)
• Fully 3-d simulation using 5 nested grids, finest resolution x=333m
• Fully compressible, nonhydrostatic
• Mixing length scheme
• Terrain-following coordinates
Coupled Ocean-Atmospheric MesoscalePrediction System (COAMPS)
Doyle and Durran (2004)
Doyle and Durran (2004)
The biggest field campaign ever mounted to studyrotors/gravity waves
T-REX
ARL White Sands Missile RangeScripps Institute of Oceanography
Colorado Research AssociatesCooperative Research in Environmental
ScienceDesert Research Institute
DLRLawrence Livermore National Laboratory
UK Met OfficeNASANCAR
Naval Research LaboratoryNOAA
Arizona State UniversityColorado State University
Harvard UniversityUniversity of Houston
University of InnsbruckUniversity of LeedsUniversity of New
HampshireNorth Carolina State
UniversityStanford UniversityUniversity of Utah
Yale University
Location of field campaign
Masts currently installed in the Owens Valley (DRI)
See www.wrcc.dri.edu/trex
Roll cloud observed over the Owens Valley, April 2004Photo by James Pinto
From Grubišić and Cohn (2004)
Roll cloud over Owens Valley March 24 2004
From Grubišić and Cohn (2004)
From Grubišić and Kuettner (2004)
T-REX Phase I
NationalForest Service
Bureau of Land
Management
Dept. ofWater
Resources
Sierra
Inyo
Valley
Location of proposed Leeds masts
Lower Sierra station site
Valley station site
Inyo station site
Sonic anemometer
GPS aerial
Solar panel
Logger box
Batteries
Temperature sensors
T-REX IOP: March – April 2006
• At least 28 10m towers• Wind profilers• Lidars• Radiosondes• NCAR Gulfstream• Univ. of Wyoming King Air• FAAM BAe146• 50 temperature loggers• 3 x 30m flux towers• Univ. Innsbruck mobile met system• …
T-REX Phase II
Map: V. Grubišić in collaboration with the UCAR Joint Office of Scientific Support
T-REX Phase II
Typical flight plans
Schematic: V. Grubišić and J. Doyle
Rotors – some key scientific questions
Climatology:
- frequency,preferred location
Dynamics
-to establish the conditions required for the formation of rotors
Modelling
- Ability of current models to predict the occurrence of rotor events
- Model validation
Summary
• Preparations in place for the most comprehensive field campaign to study rotors/lee waves ever made, using AWS, lidars, aircraft, flux towers, …
• Permissions granted for installation of a further 12 10m towers: deployment early 2005
• Phase I completed; some case studies already being undertaken in the US
Rotors pose a severe aviation hazard and have been citedas being responsible for several major accidents.Still poorly understood.