Attributes of turbulence over the Arctic Ocean with partial ice cover near Barrow, Alaska during spring 2012

Melting of the permanent ice is engendering myriad changes in the Arctic lower atmosphere. The seasonal formation and melting of the ice can produce heterogeneous surfaces with a mix of fresh ice, leads, and polynyas observed in late winter and early spring. Changes in the sea ice coverage can accelerate the exchanges of gases, particulate matter, and energy between the ocean surface and the atmosphere. As part of the BRomine, Ozone, and Mercury EXperiment (BROMEX) field campaign near Barrow, Alaska during March 2012, airborne air turbulence measurements were made using Purdue's Airborne Laboratory for Atmospheric Research (ALAR) equipped with a calibrated Best Air Turbulence Probe along several transects and as a function of altitude over the Arctic Ocean, and the frozen tundra along Alaska's North Slope. We will address two research objectives using the air turbulence measurements made over tundra snowpack, ice surfaces and leads. First, results will be presented to demonstrate how atmospheric instability and turbulence intermittency vary over the Arctic Ocean as a function of the nature of the surface. The variability of turbulence parameters (e.g., turbulent kinetic energy, isotropy, etc.), within and above the Arctic stable boundary layer, extending from 10 m (during low approaches) to about 3,500 m above the surface, will be presented and discussed. Second, results from ensembles of turbulence intermittent bursts are used to investigate whether similarity gradient-diffusion approaches can be reliably employed to determine mass and energy exchanges between the Arctic Ocean and the atmosphere. We also investigate the effects of the spatial temperature contrasts and scales of leads associated with the energy exchanges determined with the eddy covariance onboard the aircraft.