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Aerosol Optical Depth Determinations for BOREASAutomated tracking sun photometers were deployed by NASA/Ames Research Center aboard the NASA C-130 aircraft and at a ground site for all three Intensive Field Campaigns (IFCs) of the Boreal Ecosystem-Atmosphere Study (BOREAS) in central Saskatchewan, Canada during the summer of 1994. The sun photometer data were used to derive aerosol optical depths for the total atmospheric column above each instrument. The airborne tracking sun photometer obtained data in both the southern and northern study areas at the surface prior to takeoff, along low altitude runs near the ground tracking sun photometer, during ascents to 6-8 km msl, along remote sensing flightlines at altitude, during descents to the surface, and at the surface after landing. The ground sun photometer obtained data from the shore of Candle Lake in the southern area for all cloud-free times. During the first IFC in May-June ascents and descents of the airborne tracking sun photometer indicated the aerosol optical depths decreased steadily from the surface to 3.5 kni where they leveled out at approximately 0.05 (at 525 nm), well below levels caused by the eruption of Mt. Pinatubo. On a very clear day, May 31st, surface optical depths measured by either the airborne or ground sun photometers approached those levels (0.06-0.08 at 525 nm), but surface optical depths were often several times higher. On June 4th they increased from 0.12 in the morning to 0.20 in the afternoon with some evidence of brief episodes of pollen bursts. During the second IFC surface aerosol optical depths were variable in the extreme due to smoke from western forest fires. On July 20th the aerosol optical depth at 525 nm decreased from 0.5 in the morning to 0.2 in the afternoon; they decreased still further the next day to 0.05 and remained consistently low throughout the day to provide excellent conditions for several remote sensing missions flown that day. Smoke was heavy for the early morning of July 24th but cleared partially by 10:30 local time and cleared fully by 11:30. Heavy smoke characterized the rest of the IFC in both study areas.
Document ID
20020010155
Acquisition Source
Ames Research Center
Document Type
Conference Paper
Authors
Wrigley, R. C.
(NASA Ames Research Center Moffett Field, CA United States)
Livingston, J. M.
(NASA Ames Research Center Moffett Field, CA United States)
Russell, P. B.
(NASA Ames Research Center Moffett Field, CA United States)
Guzman, R. P.
(NASA Ames Research Center Moffett Field, CA United States)
Ried, D.
(NASA Ames Research Center Moffett Field, CA United States)
Lobitz, B.
(NASA Ames Research Center Moffett Field, CA United States)
Peterson, David L.
Date Acquired
August 20, 2013
Publication Date
January 1, 1994
Subject Category
Solar Physics
Meeting Information
Meeting: American Geological Union Fall Meeting
Location: San Francisco, CA
Country: United States
Start Date: December 5, 1994
End Date: December 9, 1994
Sponsors: American Geophysical Union
Funding Number(s)
PROJECT: RTOP 462-33-05
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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