METCRAX II An upcoming field investigation of downslopewindstorm-type flows on the inner sidewall of Arizona's Meteor Crater C. David Whiteman, Sebastian W. Hoch, Rich Rotunno, Ron Calhoun, Manuela Lehner, Allison Charland, Matt Jeglum, Tom Horst, Steve Semmer, Bill Brown, Norbert Kalthoff, Bianca Adler, and Roland Vogt
Arizona s Barringer Meteor Crater Diameter: 1.2 km Depth: 170 m Plain-rim: 30-50 m
Meteor Crater Location Nighttime drainage flows approach the crater from the Mogollon Rim Model: 4-6 m/s < 50 m Observations: 5-8 m/s, 35 m
Conceptual model During METCRAX-I in 2006 we found that intermittent downslope-windstorm-type flows developed over the crater s SW sidewall on clear, undisturbed nights. (See Adler et al. 2012) A new experiment, called METCRAX II, will be investigating these flows. Laboratory-like experiment continuous observations of approach flow and response of crater atmosphere.
Experimental Goal Improve understanding of hydraulic-analog atmospheric flows that produce downslope-windstorm-type events. The overall research program will combine modeling with field research to improve understanding of these flows. This presentation will focus on the design of a field program to investigate katabatically driven hydraulic-type flows at Arizona's Meteor Crater in a one-month experiment scheduled for October 2013.
Equipment placement - Sites A through E Site A Site B Site C Site D Site E Far upwind Flow field/ stratification impinging on crater topography Flow field/ stratification at rim In-Crater response Vantage point to remotely sense crater response
(km) ) Height (km) S N distance (km) spd (m s 1 ) spd (m s 1 ) S N distance (km) Height (km) q (K) Height (km) q (K) S N distance (km) q (K) q (K) low in the lee of the crater 2 285 16 0 14 8 12 10 16 14 12 10 16 14 12 10 8 120 min 10 15 20 275 8 W E distance (km) 1.9 14 12 10 Flow upwind of Crater 120 min 10 15 20 W E distance 1 (km) 280 275 300 270 295 290 285 280 275 120 285 m 120 min 0 10 15 20 More W E Model distance (km) results this afternoon 5 in the 1.7 talk by Manuela Lehner! 16 1 4 14 8 120 min 10 15 20 W E distance (km) 8 300 295 290 285 280 270 120 min 5 4 3 2 2 1.8 1.7 1.6 5 4 2 0 1.9 1.8 1.7 2 1.6 1.9 1.8 1.6 2 120 min 0 1 2 3 4 270 3 Distance (km) 0 1 295 290 280 275 1 Dist
Flow and temperature structure upwind of Crater 50 m tower Mobile Tethersonde 40 m tower u(z) u(z) u(z) Site B Site C Radar Wind Profiler SoDAR / RASS Wind-Profiling LiDAR Scanning Doppler LiDAR
Cold air damming upwind of crater Hobo temperature data loggers Site B Mobile tethersonde Between sites B and C
Flow splitting around the crater AWS 6 Automatic Weather Stations Scanning Doppler Wind LiDAR Site B LiDAR
Warm-Air Intrusions & Wind Field in Crater RHI 200S HALO PAM Co-planar RHI scans
Temperature in Crater Basin 0-400 m AGL TS TS HOBO PAM
Warm-Air Intrusions & TKE Variable Extent of Warm-Air Intrusion Sonic Effect on near-surface turbulence Sonic Pressure sensor PAM Mini-PAM / AWS : 1 level: Pressure, Sonic, T/RH
Warm-Air Intrusions & Pressure Field Pressure sensor Variable Extent of Warm-Air Intrusion
Summary METCRAX II, October 2013, will investigate katabatically driven hydraulic flows over the rim of Meteor Crater that produce warm air intrusions and hydraulic jumps. Unusual field equipment resources: 3 LiDARs and 2 tall towers Selected science issues: evolution of 3-D structure controlling upstream parameters evaluation of existing theories modeling
Project personnel - METCRAX II Matt Jeglum UU Dave Whiteman UU Sebastian Hoch UU Manuela Lehner UU Allison Charland UU Ron Calhoun Arizona State University Rich Rotunno NCAR Bill Brown NCAR Steve Semmer NCAR Tom Horst NCAR Norbert Kalthoff Karlsruhe Inst. Tech. Bianca Adler KIT Roland Vogt Uni. Basel Christian Bernhofer TU-Dresden Jan Cermak Ruhr Univ. Bochum Funded by NSF
Questions?
Warm-Air Intrusions
Warm-Air Intrusions & LiDAR siting LiDAR Siting Sites and ranges Alignment & geometry RHI co-plane or virtual towers?
Warm-Air Intrusions & LiDAR siting Sites and ranges in co-planar geometry 70-100 m blind spot 1000 m range 1-2 min / scan ASU ISS 1 km range UU
Meso-scale drainage flow formation & evolution Full Energy Balance along the slope: PAMs at A, B Mini- SoDAR observations A, B Temperature profile at B (50 m tower, RASS, Tethersonde) u(z) u(z) Pulsations & changes in wind speeds, direction, stability A ~ 5.5 km B???
32m 16 m 8 m 4 m 2 m
What is so special about Meteor Crater? Near-circular basin Surrounded by a uniform plain sloping upwards to the SW with 2% slope Uniform rim height - no major saddles or passes 170 m 50 m John S. Shelton
10m wind speed & direction Flux-PAM Instrumentation Sensible & latent heat fluxes; momentum flux; {u,v,w,tc,q } 2m P, T, RH PC-104 Linux data system 12 V solar-charged batteries 2.4 GHz radio K&Z CG4 s K&Z CM21s Soil measurements
Logistics
Synoptic situation & weather pattern Radiosondes Flagstaff NWS & (ISS- GAUSS) Wind Profiler / RASS (ISS)
ISS Locations
ISFS Instrumentation Profile Towers at sites B (50m) & C (40m) Sonic Anemometers & {T,RH} at 5m height intervals
Meso-scale drainage flow formation & evolution METCRAX 1.5: Jet nose : 6-8 m/s at 30 m AGL
The Meteor Crater A near-circular basin with a diameter of 1.2 km and a depth of 170 m. The crater's rim projects 30-50 m above an extensive surrounding plain, which is tilted upward to the southwest. During clear undisturbed nights, a shallow mesoscale drainage flow comes down this plain from a collection of plateaus and mesas (the Mogollon Rim) to interact with the crater topography. Hydraulic flows over the crater's rim lead to occasional downslope-windstorm-type events on the inner southwest sidewall of the crater, and a hydraulic jump sometimes forms locally over the sidewall. These katabatically driven events were discovered serendipitously in a previous field program at the crater, but the characteristics of the flows were not well observed with the instruments deployed during those experiments.
Warm-Air Intrusions & Pressure Field Pressure sensor Variable Extent of Warm-Air Intrusion PAM