Albedo and depth of melt ponds on sea-ice

For a 1-month period during the spring-summer season, over 500 in situ measurements of the albedo, depth and selected properties of melt ponds were made at four sea-ice sites in the Canadian Arctic Archipelago. There are three aims of the investigation: to examine the variation in spectral reflectance of melt ponds in relation primarily to clouds, pond depth, and ice type; to compute and assess with reliability, and for the first time, the statistical properties of pond depth; and to derive pond albedo parameterizations for implementation in sea-ice model simulations. It was found that pond reflectance curves vary significantly with cloud cover, pond depth, and ice type. A simple univariate statistical analysis showed that surface ice morphology controls pond depth. Application of the Kruskal-Wallis test evidenced that differences between first-year ice, multiyear ice, and landfast ice-pond-depth distributions are statistically significant. Lastly, calibrated non-linear regression functions show that visible and near-infrared pond albedos decrease exponentially with depth until some critical depth value is exceeded. The relationship is weakest in the visible spectrum, particularly under cloudy sky conditions.