Radiation:
Spectral reflected
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Radiation: |
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The reflectance of sunlight from the surface is important for understanding the surface heat budget of the ice cover and for interpreting visible and near-infrared remote sensing signatures. Because of this significance we made measurements of spectral reflectance on 19 days while the ship was in transit. An Analytical Spectral Devices FieldSpecPro spectroradiometer. The instrument provided spectral coverage from 375 to 2500 nm. It was the same device used for the spectral incident measurements with a a narrow (1, 5, or 17 degree) field of view lens used instead of a cosine collector . Measurements were typically made near solar noon from the flying bridge of the ship. Sky conditions were usually cloudy, with the solar disk not visible. Measurements were made in pairs: the reflectance from the surface and the from a white reference standard. The foreoptics were aimed at a 45 degree angle. The reflectances were scaled by 0.83 to account for shadowing and the white standard. Two types of observations were made: i) sampling at set time intervals or ii) selecting ice types. Mean values of spectral reflectances for
the surveys are plotted on the right. The gaps are due to small values of
incident irradiance due to low sun angles and cloudy skies. Individual results can be accessed using the
links in the table below. |
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