Derivation of melt pond coverage on Arctic sea ice using MODIS observations

The formation of meltponds on the surface of sea ice during summer is one of the main factors affecting variability in surface albedo over the ice cover. However, observations of the spatial extent of ponding are rare. To address this, a MODIS surface reflectance product is used to derive the daily melt pond cover over sea ice in the Beaufort/Chukchi Sea region through the summer of 2004. For this region, the estimated pond cover increased rapidly during the first 20 days of melt from 10% to 40%. Fluctuations in pond cover occurred through summer, followed by a more gradual decrease through late August to 10%. The rapid initial increase in pond cover occurred later as latitude increased and melt progressed northward.A surface campaign at Barrow in June 2004 provided pond and ice spectral reflectance needed by the MODIS algorithm to deduce pond coverage. Although individual pond and ice reflectance varies within the comparatively small region of measurement, the mean values used within the algorithm ensured that relevant values (i.e. concurrent with satellite observations) were being applied.Aerosonde unpiloted aerial vehicles (UAVs) were deployed in June 2004 from Barrow, Alaska, to photograph the sea ice so melt pond cover could be estimated. Although the agreement between derived pond cover from UAV photos and estimates from MODIS varies, the mean estimates and distribution of pond coverages are similar, suggesting that the MODIS technique is useful for estimating pond coverage throughout the region. It is recommended that this technique be applied to the entire Arctic through the melt season.