HeloAlb: On a few of the helo flights the ASD Ice-1 spectroradiometer was used to measure 
incident and reflected irradiance. One detector was mounted on a metal plate with an unobstructed 
view looking downward. The other detector was mounted high on the fuselage looking upward. 
Unfortunately the field of view of this detector was somewhat blocked by the cowling of the 
helicopter. To minimize the effects of this we: 1) only measured on cloudy days with a 
dense uniform cloud cover and 2) tried to calibrate the two sensors in the working 
configuration by measuring a lead, where the surface was uniform and the albedo known. 
Our precautions were only partially successful. Discrete jumps occurred when the helicopter 
turned to do a different leg of the flight pattern. These jumps are artifacts of sensor shadowing. 
Information can be obtained from the legs where the incident detector was not shadowed.