Aerial observations
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Aerial observations |
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| A crucial
element of SHEBA is to extend process-oriented observations and models to
larger-scales. Local measurements provide data on mass changes, optical
properties, and structural properties of individual ice categories, and ground surveys allowed us to define spatial variability within each
category. We then use larger scale aerial surveys to generate regional
estimates of the
fractional area covered by these categories.
Combining these observations with process-oriented modeling results makes it
possible to generate areally averaged estimates of such quantities as
albedo, solar heat input to the ice and ocean, ice concentration,
pond fraction, and lateral melt rates.
Between May and October 1998 more than a dozen helicopter survey flights were made. An instrument package consisting of a Nikon 35-mm camera, a videocamera, and a KT-19 thermal radiometer was mounted, in a downward-looking orientation, on the back of the helicopter's storage compartment. Whenever possible surveys were flown at an altitude of 6000 ft under either clear skies or high clouds. The flight pattern was a box centered on the Des Groseilliers. The first leg was 25 km east followed by 25 km due north, 50 km due west, 50 km south, then 25 km east, and finally 25 km north back to the ship.
From left to right the instruments are Nikon 35-mm camera with film pack and motor drive, KT-19 thermal radiometer, Hi-8 video camera, and downwarding-looking spectroradiometer. |
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Helicopter doing airborne oceanography.
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Instrument package mounted on edge of helo storage compartment. |
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