August 17: 16:09:41 - 21:21:47 UTC

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The main feature for the first hour of this animation is a convective boundary layer well-capped below 500 m altitude. At 17:20 clouds begin to appear (white in upper right corner). As the cloud-base lowers, the boundary layer grows and a clean layer (low aerosol scattering, black in color) emerges at 18:30 between 1.5-2.0 km altitude. The clouds are the result of convective storms moving over the lidar site from the Rocky Mountains located immediately west of Boulder. At approximately 20:00 UT we begin to see pulses of clean air (blue) advecting under the polluted boundary layer air. The animation suggests this is one method by which boundary layer pollution can be lofted.

Boulder, CO, Foothills Lab: 12 August 2004: 16:21 - 23:38 UTC

Quicktime [75.3 MB]

This RHI-scan animation is directed toward 285-degrees azimuth. Range rings are drawn in intervals of 1000 m. The horizontal smoothness of the aerosol layer (red) at 1.3 km altitude indicates stability at that altitude at the beginning of the animation. During the course of the day, a turbulent convective boundary layer grows from beneath the layer and gradually entrains it. One can also notice an increase in aerosol scattering throughout the day and "sloshing" of the boundary layer presumably due to mesoscale wave activity.

Boulder, CO, Foothills Lab: 8 July 2004:
15:38 - 17:11 UTC

Quicktime [13.3 MB]

This RHI-scan animation is directed toward 285-degrees azimith. Range
rings are drawn in intervals of 500 m. It shows complex interaction between what appears to be a convective boundary layer (from the surface to about 500 m height) and strong westerly flow and wave activity from aloft.

Boulder, CO, Foothills Lab: 1 July 2004: 22:27 - 23:04 UTC

Quicktime [8.72 MB]

This PPI-scan animation at an elevation angle of 3.9 degrees shows advection of aerosol plumes across north Boulder during a period of NE flow. Range rings are in intervals of 1 km. The composition of the aerosol plumes are unknown.

Boulder, CO, Foothills Lab: 29 June 2004: 16:23 - 17:28 UTC

Quicktime [6.39 MB]

This RHI-scan animation directed to the north shows the mixing action of a convective boundary layer. Wave activity in the capping inversion layer can also be noted. The red plume that emerges at 1.1 km range at 16:29 is the exhaust from a diesel-electric locomotive. Note that large-eddies carried the plume to the top of the CBL (500-600 m) within a few minutes.

Boulder, CO, Foothills Lab: 25 June 2004: 20:10 - 21:09 UTC

Quicktime [8.39 MB]

This PPI-scan animation at an elevation angle of 3.1 degrees shows aerosols advecting under weak wind conditions. One particularly interesting feature is the exhaust plume of a diesel-electric locomotive that penetrates the scan surface at 20:20 at about 500-800 m range and can be followed as an emerging line of pollutants until about 20:30 UTC as it moves to the NE. Range rings are drawn in 500 m intervals.

Boulder, CO, Foothills Lab: 25 June 2004:
22:11 - 23:16 UTC

Quicktime [8.39 MB]

This PPI-scan animation at an elevation angle of 3.1 degrees shows the attenuating effects of a brief rain shower passing over the REAL site. Range rings are drawn in intervals of 500 m.