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DRI Stereo Cloud Imaging
Terrain-induced Rotor Experiment (T-REX)
Special Observation Period in March-April 2006
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Principal Investigator and Contact:
Dr. Vanda Grubisic
Division of Atmospheric Sciences
Desert Research Institute
2215 Raggio Parkway
Reno, NV 89512-1095
Phone: (775) 674-7031
Fax : (775) 674-7016
E-mail : Vanda.Grubisic@dri.edu
1. General Description
The location of the T-REX field activities was Owens Valley in the southern Sierra Nevada in eastern California. The enclosed data represents QuickTime animations of stereo cloud images for a number of days during the T-REX Special Observations Period obtained by the DRI stereo cloud imaging system.
2. Stereo Cloud Imaging Location
The cloud imaging system was located at the south end of Owens Valley, west of Lone Pine, in between Alabama Hills and Mt. Whitney. The coordinates of the two cameras, i.e., GPS latitude, longitude and altitude, are specified for each of the dates at the end of this file. The coordinates were measured using GPS post-processed data and the error in position measurements in all three directions is less than 0.5 m.
3. File Naming Convention
Data files are named using the following notation: S-yyyymmdd.mov, where S stands for stereo, yyyy is a four-digit year, mm is a two-digit month, and dd is a two-digit day.
4. Data Set Description
The data is in the QuickTime movie format, compressed with a H.264 video codec. Each frame in the movie consists of two images of resolution of about 720 x 480 pixels placed side by side. The right-camera image is placed on the left side and left-camera image on the right side in order to facilitate, the so-called cross-eyed, unaided (naked-eye) stereo viewing on any computer screen. The temporal resolution of the data set is 5-10 sec with some gaps caused by failure of synchronized camera triggering. The precise GPS coordinates and time are written at the bottom of each frame. The time is local time.
5. Description of the Instrumentation
Two Cannon 20D digital 8 Mpixel cameras were used with radio-synchronized triggering for shorter baseline distances and two manually synchronized timers for larger baseline distances. The baseline distances used were from about 80 m to 670 m.
6. Use of the Animations
Please use the following citation as an acknowledgement, if using these animations in any scientific report/paper/presentation:
"These stereo cloud images were gathered as part of the Terrain-induced Rotor Experiment (T-REX). The primary sponsor of T-REX was the US National Science Foundation. The acquisition of this data was led by the PI Grubisic team from the Desert Research Institute funded in part by NSF grants ATM-0242886 and ATM-0524891 to DRI. "
If the contribution of this data product is significant to the publication/presentation, the DRI PI should be offered the right to joint authorship.
Any redistribution of this data must include this data acknowledgement statement.
7. Data Collection Notes
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T-REX Stereo Cloud Imaging Notes
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Date: 20060302, IOP-1
NAD_83 (EPOCH 2002.0) Lat/deg, Long/deg, E. Height/m
GPS L: 36.62466011, -118.15587742, 1526.947
GPS R: 36.62495212, -118.15523944, 1523.511
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Data Collection Setup
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Left Camera: Camera A, Station 20060302-A
Right Camera: Camera B, Station 20060302-B
Horizontal Baseline: 66 m
Lens Focal Distance: 24 mm
Vertical Angle: 15? degrees
Trigger Interval: 5 s
Start Time: 2006-03-02 23:50 UTC
End Time: 2006-03-03 00:40 UTC
Operators: Boro Grubisic
Brian Billings
Ivana Stiperski
This was a test of the camera alignment and radio triggers in the filed. We drove as far west as we could in the Alabama Hills and than carried the equipment on foot for another kilometer or so, to the northern slope of a small rocky outcrop. The camera positions were chosen to be at approximately the same altitude and with unobstructed view of the T-REX theatre of operations to the north of Alabama Hills. The camera platforms were first leveled to be horizontal, then the cameras were turned to point in each other's direction and centered (both left-right and up-down) in the viewfinder. Note that the cameras were not horizontal after this adjustment, as the left and right cameras are generally at different altitudes ( In this case camera A was about 3 m higher than camera B). The left camera was then turned 90 degrees counter-clockwise and the right camera was turned 90 degrees clockwise. Finally, both cameras were lifted up by the same angle (oral tradition has it that the angle was 15 degrees, but written notes have been lost). The site was somewhat hard to access and the achievable baseline rather short, so we decided to look further next time. The radio transmitter sending the triggering signal was in the middle between the two camera stations and two receivers were connected one to each camera.
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Date: 20060305, IOP-2
NAD_83 (EPOCH 2002.0) Lat/deg, Long/deg, E. Height/m
GPS L: 36.62819615, -118.13773316, 1461.603
GPS R: 36.62857514, -118.13693206, 1460.585
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Data Collection Setup
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Left Camera: Camera A, Station 20060305-A
Right Camera: Camera B, Station 20060305-B
Horizontal Baseline: 83 m
Lens Focal Distance: 24 mm
Vertical Angle: 15? degrees
Trigger Interval: 10 s
Start Time: 2006-03-05 23:20 UTC
End Time: 2006-03-06 01:25 UTC
Operators: Boro Grubisic
Brian Billings
Ivana Stiperski
This was primarily a test of the camera alignment and radio triggers in the filed on a new and much better site. The new site was a nice and quite level part of Alabama Hills easily accessible with a 4-wheel drive vehicle. The baseline was still rather short, in order to facilitate visual camera alignment, but the site was level enough for much larger baselines. We changed the alignment procedure this time. The camera platforms were first leveled to be horizontal, then they were turned to point in each other's direction and centered in the viewfinder only in the left-right direction, thus leaving the camera platforms horizontal. The left camera was then turned 90 degrees counter-clockwise and the right camera was turned 90 degrees clockwise. Finally, both cameras were lifted up by the same angle (15 degrees, according to the oral tradition). This alignment procedure was used throughout the rest of the campaign. Radio trigger synchronization was used.
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Date: 20060316
NAD_83 (EPOCH 2002.0) Lat/deg, Long/deg, E. Height/m
GPS L: 36.62741718, -118.13782855, 1464.547
GPS R: 36.62869247, -118.13661423, 1461.552
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Data Collection Setup
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Left Camera: Camera B, Station 20060316-B
Right Camera: Camera A, Station 20060316-A
Horizontal Baseline: 178 m
Lens Focal Distance: 10 mm
Vertical Angle: 29 degrees
Trigger Interval: 5 s
Start Time: 2006-03-16 22:25 UTC
End Time: 2006-03-17 01:15 UTC
Operators: Boro Grubisic
Brian Billings
Ivana Stiperski
Radio trigger synchronization.
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Date: 20060323
NAD_83 (EPOCH 2002.0) Lat/deg, Long/deg, E. Height/m
GPS L: 36.62584194, -118.14271173, 1478.487
GPS R: 36.62892052, -118.13631440, 1464.240
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Data Collection Setup
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Left Camera: Camera B, Station 20060323-B
Right Camera: Camera A, Station 20060323-A
Horizontal Baseline: 666 m
Lens Focal Distance: 10 mm
Vertical Angle: 30 degrees
Trigger Interval: 5 s
Start Time: 2006-03-24 00:00 UTC
End Time: 2006-03-24 01:40 UTC
Operators: Boro Grubisic
Brian Billings
Ivana Stiperski
No radio synchronization. The baseline was increased to enhance the stereo effect. Such large distance was beyond the radio trigger range, so, we used two separate timers that were initially synchronized manually, by one person pressing the start button at the same time on both timers. The two ticking timers where then connected one to each camera. The synchronization achieved was between about 0.1 to 0.5 seconds during the whole shooting interval. Camera A incorrectly stayed at 22mm focal length for a long time, so, there is only a small number of good stereo images.
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Date: 20060324, IOP-6
NAD_83 (EPOCH 2002.0) Lat/deg, Long/deg, E. Height/m
GPS L: 36.62584194, -118.14271173, 1478.487
GPS R: 36.62892052, -118.13631440, 1464.240
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Data Collection Setup
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Left Camera: Camera B, Station 20060323-B
Right Camera: Camera A, Station 20060323-A
Horizontal Baseline: 666 m
Lens Focal Distance: 10 mm
Vertical Angle: 30 degrees
Trigger Interval: 10 s
Start Time: 2006-03-24 22:35 UTC
End Time: 2006-03-25 01:05 UTC
Operators: Brian Billings
Ivana Stiperski
Both cameras set to f8, 1/640.
No radio synchronization.
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Date: 20060325, IOP-6
NAD_83 (EPOCH 2002.0) Lat/deg, Long/deg, E. Height/m
GPS L: 36.62584194, -118.14271173, 1478.487
GPS R: 36.62892052, -118.13631440, 1464.240
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Data Collection Setup
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Left Camera: Camera B, Station 20060323-B
Right Camera: Camera A, Station 20060323-A
Horizontal Baseline: 666 m
Lens Focal Distance: 10 mm
Vertical Angle: 29.5 degrees
Trigger Interval: 10 s
Start Time: 2006-03-25 26:40 UTC
End Time: 2006-03-26 00:50 UTC
Operators: Boro Grubisic
Brian Billings
Ivana Stiperski
Both cameras initially set to f8, 1/500, until about 0020 UTC, automatic shutter speed after that. Changed memory cards at about 2215 UTC (Camera A) and 2225 (Camera B), Camera A had some shots with 5.0 apeture after this point. No radio synchronization.
Wave clouds and rotors visible over the study area during the morning. Moderate southerlies turning to dead calm. During the afternoon, some isolated roll clouds, with mainly cap cloud making variable penetrations into the valley. Strong westerlies with some sideways rain. Dead calm period around 0015 UTC. Spectacular lenticular, roll cloud, and dust lofting visible over Owens Lake. After stereo session, took some single shots from Onion Valley road and of roll cloud north of Independence. Very strong westerlies and some strong easterlies in and north of Independence.
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Date: 20060329
NAD_83 (EPOCH 2002.0) Lat/deg, Long/deg, E. Height/m
GPS L: 36.62667734, -118.14053301, 1470.988
GPS R: 36.62892052, -118.13631440, 1464.240
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Data Collection Setup
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Left Camera: Camera B, Station 20060325-B
Right Camera: Camera A, Station 20060323-A
Horizontal Baseline: 453 m
Lens Focal Distance: 10 mm
Vertical Angle: 29 degrees
Trigger Interval: 10 s
Start Time: 2006-03-29 20:15 UTC
End Time: 2006-03-30 00:00 UTC
Operators: Brian Billings
Yanping
Both cameras set to f8, 1/640.
No radio synchronization. Primarily a test of the camera system. Detached cumulus rolls in the morning gave way to stratiform cloud flowing down the Sierra slopes through most of the afternoon, with gradual clearing toward the end of the photo session. Some isolated cumulus in viewing area, with more extensive cumulus over Inyos and Owens Lake.
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Date: 20060331, IOP-8
NAD_83 (EPOCH 2002.0) Lat/deg, Long/deg, E. Height/m
GPS L: 36.62667734, -118.14053301, 1470.988
GPS R: 36.62892052, -118.13631440, 1464.240
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Data Collection Setup
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Left Camera: Camera B, Station 20060325-B
Right Camera: Camera A, Station 20060323-A
Horizontal Baseline: 453 m
Lens Focal Distance: 10 mm
Vertical Angle: 29 degrees
Trigger Interval: 5 s
Start Time: 2006-03-31 23:05 UTC
End Time: 2006-04-01 00:10 UTC
Operators: Brian Billings
Ivana Stiperski
Both cameras set to f8, 1/400.
No radio synchronization. Attempted to coordinate with IOP 8 King Air flight, but delayed by transportation issues and King Air flight aborted. Cloud cover all of cumuliform variety with no obvious organizational structure. Moderately strong south winds during majority of session.
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Date: 20060402, IOP-9
NAD_83 (EPOCH 2002.0) Lat/deg, Long/deg, E. Height/m
GPS L: 36.62584194, -118.14271173, 1478.487
GPS R: 36.62892052, -118.13631440, 1464.240
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Data Collection Setup
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Left Camera: Camera B, Station 20060323-B
Right Camera: Camera A, Station 20060323-A
Horizontal Baseline: 666 m
Lens Focal Distance: 10 mm
Vertical Angle: 29 degrees
Trigger Interval: 10 s
Start Time: 2006-04-02 16:45 UTC
End Time: 2006-04-02 21:40 UTC
Operators: Brian Billings
Ivana Stiperski
Both cameras set to f8, 1/250.
No radio synchronization. Missing spare memory cards, so coordinated with Hiaper flight over Owens Valley. For the first time, we were setup before the best clouds formed, so formation and dissipation were captured. Nice lenticulars formed during the first 15-30 minutes of the shoot. Most clouds concentrated over the Sierra and first wave crest. Near noon, a thin line of cirrus extended over the valley in advance of the rest of the overcast. Winds were moderate and mostly southerly, with possible westerly gusts.
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Date: 20060408, IOP-10
NAD_83 (EPOCH 2002.0) Lat/deg, Long/deg, E. Height/m
GPS L: 36.62584194, -118.14271173, 1478.487
GPS R: 36.62892052, -118.13631440, 1464.240
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Data Collection Setup
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Left Camera: Camera B, Station 20060323-B
Right Camera: Camera A, Station 20060323-A
Horizontal Baseline: 666 m
Lens Focal Distance: 10 mm
Vertical Angle: 29 degrees
Trigger Interval: 10 s
Start Time: 2006-04-08 14:15 UTC
End Time: 2006-04-08 19:15 UTC
Operators: Brian Billings
Ivana Stiperski, Heather
Both cameras set to f8, 1/250.
No radio synchronization. Coordinated with HIAPER IOP 10 flight. Generally clear skies to begin. Moisture began to move in shortly after shooting began. One lenticular formed and dissipated in the center of the valley. Numerous lenticulars were observed upstream of the Sierra crest. A train of cirrus waves moved across the valley during the shooting session.
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Date: 20060409, IOP-11
NAD_83 (EPOCH 2002.0) Lat/deg, Long/deg, E. Height/m
GPS L: 36.62584194, -118.14271173, 1478.487
GPS R: 36.62892052, -118.13631440, 1464.240
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Data Collection Setup
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Left Camera: Camera B, Station 20060323-B
Right Camera: Camera A, Station 20060323-A
Horizontal Baseline: 666 m
Lens Focal Distance: 10 mm
Vertical Angle: 29.5 degrees
Trigger Interval: 5 s
Start Time: 2006-04-09 22:15 UTC
End Time: 2006-04-10 00:40 UTC
Operators: Brian Billings
Ivana Stiperski
Both cameras set to f8, 1/500.
No radio synchronization. Coordinated with afternoon King Air flight. High overcast quickly transitioned into a well-defined cloud (wave or wave-organized) over the center of the valley. Rolling cumulus were observed early in the shoot. Better defined lenticulars over Owens Lake. Lower overcast developed again toward the end of the shoot. Southerly winds became very strong, then abruptly calmed out. Isolated westerlies occurred later, but still before local sunset.
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Date: 20060411, IOP-12
NAD_83 (EPOCH 2002.0) Lat/deg, Long/deg, E. Height/m
GPS L: 36.62584194, -118.14271173, 1478.487
GPS R: 36.62892052, -118.13631440, 1464.240
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Data Collection Setup
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Right Camera: Camera A, Station 20060323-A
Left Camera: Camera B, Station 20060323-B
Horizontal Baseline: 666 m
Lens Focal Distance: 10 mm
Vertical Angle: 29.5 degrees
Trigger Interval: 5 s
Start Time: 2006-04-11 16:15 UTC
End Time: 2006-04-11 18:30 UTC
Operators: Brian Billings, Suzanne
Ivana Stiperski
Both cameras set to f8, 1/400.
No radio synchronization. Attempted to coordinate with King Air flight. Cloud over the Sierra crest throughout session. Cloud over Owens Valley cleared shortly after shooting began with the exception of cumulus and cirrus apparently associated with gap jets. Later, cumulus began circling the Alabama Hills. Higher cloud began to move in late, and precipitation descended further down the Sierra slopes. Winds were southerly throughout and increased in strength near the end of the session.
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Date: 20060415, IOP-13
NAD_83 (EPOCH 2002.0) Lat/deg, Long/deg, E. Height/m
GPS L: 36.62584194, -118.14271173, 1478.487
GPS R: 36.62892052, -118.13631440, 1464.240
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Data Collection Setup
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Left Camera: Camera B, Station 20060323-B
Right Camera: Camera A, Station 20060323-A
Horizontal Baseline: 666 m
Lens Focal Distance: 10 mm
Vertical Angle: 29 degrees
Trigger Interval: 10 s
Start Time: 2006-04-15 14:50 UTC
End Time: 2006-04-15 23:05 UTC
Operators: Brian Billings
Ivana Stiperski
Both cameras set to f8, 1/400.
No radio synchronization. Shot at medium resolution to maximize shooting time. Large, long-wavelength lenticular extending south to Mount Whitney in place at the start of the shoot. Clearing occurred after sunrise, but lenticulars remained in favored place over Inyos for longer. Small cumulus patches began forming just to the lee of the Sierra and above the slopes, which increased in size throughout the rest of the shoot. Remained near the lee side and grew above the crest, but did not organize into a line structure. High lenticulars began to reappear later in the afternoon.
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Date: 20060416, IOP-13
NAD_83 (EPOCH 2002.0) Lat/deg, Long/deg, E. Height/m
GPS L: 36.62584194, -118.14271173, 1478.487
GPS R: 36.62892052, -118.13631440, 1464.240
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Data Collection Setup
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Left Camera: Camera B, Station 20060323-B
Right Camera: Camera A, Station 20060323-A
Horizontal Baseline: 666 m
Lens Focal Distance: 10 mm
Vertical Angle: 29 degrees
Trigger Interval: 10 s
Start Time: 2006-04-16 15:15 UTC
End Time: 2005-04-16 23:15 UTC
Operators: Brian Billings
Johanna
Both cameras set to f8, 1/250.
No radio synchronization. Shot at medium resolution to maximize shooting time. First few shots of camera A are on high zoom. Lenticulars were in place over Sierra crest when shooting began. These clouds gradually became convective from the south northward, and then convection spread over the valley. Strong southerly winds developed at this time which created a major dust storm, which was diverted around the shooting area and into the study area. After the dust storm abated, strong westerly and southwesterly winds began at the shooting area. However, skies cleared during this time except for cap clouds over the crest of the Sierra Nevada.
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Date: 20060426, IOP-15
NAD_83 (EPOCH 2002.0) Lat/deg, Long/deg, E. Height/m
GPS L: 36.96341536, -118.10914497, 2707.589
GPS R: 36.96647113, -118.11203906, 2723.680
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Data Collection Setup
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Left Camera: Camera B, Station 20060426-B
Right Camera: Camera A, Station 20060426-A
Horizontal Baseline: 425 m
Lens Focal Distance: 10 mm
Vertical Angle: 29.5 degrees
Trigger Interval: 10 s
Start Time: 2006-04-26 18:20 UTC
End Time: 2006-04-26 22:15 UTC
Operators: Boro Grubisic
Brian Billings
Ivana Stiperski
Both cameras set to f8, 1/500.
Radio synchronization used, with the transmitter at camera station A and receiver at camera station B. Easterly wind case. No wave clouds. Overcast. Camera B lens was not initially set at 10mm, and when eventually set at 10mm, the radio pole was visible in the frame.
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Date: 20060427
NAD_83 (EPOCH 2002.0) Lat/deg, Long/deg, E. Height/m
GPS L: 37.35207491, -118.31743978, 1210.355
GPS R: 37.35238620, -118.31492497, 1211.977
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Data Collection Setup
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Left Camera: Camera B, Station 20060427-B
Right Camera: Camera A, Station 20060427-A
Horizontal Baseline: 226 m
Lens Focal Distance: 10 mm
Vertical Angle: 29.5 degrees
Trigger Interval: 10 s
Start Time: 2006-04-27 15:35 UTC
End Time: 2006-04-27 20:05 UTC
Operators: Boro Grubisic
Brian Billings
Ivana Stiperski
Both cameras set to f8, 1/320.
Two GPS PPS counters used for synchronization. Easterly wind case. Some wave clouds.