Heterogeneity of sea ice surface temperature at SHEBA from aircraft measurements

[1] Large variations in surface temperature of sea ice occur on a seasonal scale, and spatial variations are also significant due to exposure of open water in leads and varying thickness of sea ice. In this paper we examine aircraft, ground-based, and satellite measurements of sea ice surface temperature over the region surrounding the Surface Heat Budget of the Arctic Ocean (SHEBA) ice station. Aircraft measurements from May and July demonstrate the spatial and temporal variability of surface temperature for the consolidated ice pack and for leads over the local area (which is defined here as the 30 × 30 km square observed by the aircraft). Data from May show a large increase in surface temperature during the month, but spatial variability of the thick ice temperature over the local area is not large with standard deviations on the order of 0.5 K. Surface temperatures during the melt season (July) were more uniform and near freezing as expected. Standard deviations during this period are smaller than in spring. Our analysis shows that surface temperature at a point (the SHEBA ice station) approximates the mean value over the local area during late spring and summer with an RMS error of 0.75 K. Lead temperatures cannot be reliably represented by the point measurements at the ice station. Surface temperature retrievals from advanced very high resolution radar (AVHRR) were compared with aircraft and ground-based measurements in late May. Mean surface temperature values over the local area as derived from AVHRR and aircraft measurements were within 1.5 K of each other. Mean surface temperatures over varying spatial scales were calculated and found to differ by as much as 1.3 K from local to regional scales (500 km) in late May.