METCRAXMETCRAXThe Meteor Crater The Meteor Crater

ExperimentExperimentAn Upcoming Study of Cold Air Pools and An Upcoming Study of Cold Air Pools and

Seiches in Arizona’s Meteor CraterSeiches in Arizona’s Meteor Crater

Maura Hahnenberger and C. David Whiteman, Maura Hahnenberger and C. David Whiteman, University of UtahUniversity of Utah

Andreas Muschinski, U of Mass AmherstAndreas Muschinski, U of Mass AmherstSharon Zhong, University of HoustonSharon Zhong, University of Houston

David C. Fritts, Northwest Research Associates, David C. Fritts, Northwest Research Associates, Inc.Inc. © John S. Shelton© John S. Shelton

METCRAX overviewMETCRAX overview 3 year meteorological research program 3 year meteorological research program

supported bysupported by NSF grantsNSF grants NCAR field support NCAR field support

PIs: Andreas Muschinski, Dave Fritts, Dave PIs: Andreas Muschinski, Dave Fritts, Dave Whiteman, Sharon ZhongWhiteman, Sharon Zhong

Field phase: October 2006Field phase: October 2006 Continuous measurements during monthContinuous measurements during month ~8 intensive observational periods (IOPs) in which ~8 intensive observational periods (IOPs) in which

tethersondes and rawinsondes will be flowntethersondes and rawinsondes will be flown Numerical modeling and analysisNumerical modeling and analysis

METCRAX ObjectivesMETCRAX Objectives

Seiches & Internal WavesSeiches & Internal Waves Determine the role played in transport Determine the role played in transport

and mixing in basin stable layersand mixing in basin stable layers Temperature Inversions & Cold Air Temperature Inversions & Cold Air

PoolsPools Investigate the diurnal buildup and Investigate the diurnal buildup and

breakdown and the associated physical breakdown and the associated physical and dynamical processesand dynamical processes

MotivationMotivation Inversion EvolutionInversion Evolution

Physical processes are poorly Physical processes are poorly understood in complex terrainunderstood in complex terrain

Leading forecast problem in the Leading forecast problem in the Western USWestern US

Improved understanding may lead to Improved understanding may lead to better forecastsbetter forecasts

Understanding of physics may be Understanding of physics may be easier in simple laboratory-like easier in simple laboratory-like conditionsconditions

Why the Meteor Crater?Why the Meteor Crater?

On a flat plainOn a flat plainUniform rim heightUniform rim height

No large-scale advectionNo large-scale advectionThe right sizeThe right size

Seiches/Gravity WavesSeiches/Gravity Waves

Basin cold pools can exhibit Basin cold pools can exhibit oscillations similar to a basin of oscillations similar to a basin of waterwater

Seiches have been observed in Seiches have been observed in lake basinslake basins

Have not yet been studied in Have not yet been studied in atmosphereatmosphere

Cold Pool Buildup/BreakupCold Pool Buildup/Breakup

Determine physical processes that Determine physical processes that govern buildup/breakupgovern buildup/breakup Slope flowsSlope flows Radiative transfer (long- and short-wave)Radiative transfer (long- and short-wave) Turbulent transferTurbulent transfer Asymmetries in BL structure and evolutionAsymmetries in BL structure and evolution Ambient flows above basinAmbient flows above basin

Preliminary MeasurementsPreliminary Measurements

Crater Rim & Floor Crater Rim & Floor Temperatures, Oct. 2005Temperatures, Oct. 2005

- (triangle) 1 ISS (triangle) 1 ISS - (dashed lines) 50 - (dashed lines) 50 HOBOs HOBOs - (square) 7 ISFFs- (square) 7 ISFFs - (X) 3 tethersondes- (X) 3 tethersondes

InstrumentationInstrumentation

ISSISS

ISFFISFFHOBOHOBOTethered balloon Tethered balloon sounding systemsounding system

Field Plan: 1-31 October Field Plan: 1-31 October 20062006

Continuous observations:Continuous observations: Outside the CraterOutside the Crater

Radar profiler/RASSRadar profiler/RASS Doppler sodar/RASSDoppler sodar/RASS Weather station, 1 ISFF tower, HOBOsWeather station, 1 ISFF tower, HOBOs

Inside the CraterInside the Crater 6 ISFF towers - 5 on slopes, 1 on rim6 ISFF towers - 5 on slopes, 1 on rim HOBOs, N-S and E-W lines across craterHOBOs, N-S and E-W lines across crater

Special IOP operations:Special IOP operations: Outside the CraterOutside the Crater

Rawinsondes at 3-h intervalsRawinsondes at 3-h intervals Inside the CraterInside the Crater

Tethered balloon soundings, 3pm to 10am to 325 mTethered balloon soundings, 3pm to 10am to 325 m

Questions?Questions?

© John S. Shelton© John S. Shelton