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Accomplishments

Estimating surface albedo from passive microwave satellite observations.
The linear model was developed, approximating the AVHRR-derived clear-sky broadband albedo by the surface air temperature measurements from the International Arctic Buoy Program (IABP/POLES SAT), SSM/I brightness temperatures and SSM/I-derived sea ice characteristics (concentration, age, thickness). Figure 1 shows changes in the surface broadband albedo, estimated from different satellite observations.

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Figure 1. Interannual, seasonal and latitudinal changes of surface broadband clear-sky albedo estimated from the AVHRR (source) and the integrated satellite-observation model (fitted).
The derived approximation of the surface broadband albedo by the passive microwave data was validated over SHEBA in situ observations. Figure 2 shows the results of this approximation. Mean July melt pond concentration (1990-1999) was 26%. There was a strong correlation observed between melt pond concentrations and surface albedo (r=-0.74).
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Figure 2. Seasonal, interannual and regional changes in the Arctic sea ice albedo and melt pond concentrations. a-c) melt ponds in the melting area (observed from melt onset date through freeze onset date, or, from melt onset date through ice disappearing date), d) melt ponds for the whole ice covered Arctic.

Figures 3 and 4 show monthly mean (July) melt pond concentrations and sea ice albedo.

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Figure 3. Interannual changes in the monthly mean (July) melt pond concentrations during 1990-1999 from passive microwave satellite observations.
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Figure 4. Interannual changes in the monthly mean (July) all-sky surface broadband albedo for 1990-1999 from passive microwave satellite observations derived using least square method.
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