Surface Energy Balance and Turbulence Characteristics Observed at the SHEBA Ice Camp During FIRE III

摘要

The Institute for Marine and Atmospheric Research Utrecht (IMAU) participated inudthe FIRE III (First ISCCP Regional Experiment, ISCCP International Satellite CloududClimatology Project) experiment in May 1998. In this paper we describe surface layerudmeasurements performed on the sea ice at the SHEBA (Surface Heat and Energy Balance ofudthe Arctic ocean) camp and compare these with measurements collected above a grasscoveredudsurface in Cabauw, the Netherlands. The observations consist of both highfrequencyudturbulence measurements and mean-profile measurements of wind, temperatureudand humidity. In addition, we measured the upward and downward components of both theudlongwave and shortwave radiation, and the snow and ice temperatures in the upper 40 cm.udThe observations give a detailed picture of all components of the energy balance of theudArctic sea-ice surface.udThe turbulence measurements are used to study the surface layer scaling of theudturbulence variables in the stable boundary layer. More specifically, we showed that theudintegral length scale of the vertical velocity fluctuations serves as the relevant turbulenceudlength scale. The monthly-averaged energy balance of the Arctic sea-ice was dominated byudradiative fluxes, whereas, the sensible and latent heat flux and the energy flux into theudsurface were rather small. A detailed inspection of the diurnal variations in the turbulentudfluxes however indicates that although the monthly-averaged values are small, the hourlyaveragedudvalues for these fluxes are significant in the surface energy balance.