Description of task
Investigations of several models’ representation of boundary-layer processes using the SHEBA data set will provide insight into the problems and lay a foundation for the planned experiments.
Arctic expeditions with an ABL measurement program will be made in the summer of 2007 with a Swedish ice-breaker, and for a longer period during IPY by a Russian drifting ice station. Fluxes of heat and sea spray will be obtained from RV Oceania during summer expeditions to the Arctic. Routine atmospheric measurements including rawinsonde and ice data obtained by RV Polarstern during the ARCTIC expeditions in the summers 2007, 2008, 2009 will be analysed. Measurements of the structure of the ABL and turbulent fluxes will be made using research aircraft as well as ground - and ship-based remote sensing and in situ instruments. ABL observations from 1995 (REFLEX), 1998 (ARTIST), 1997-1998 (SHEBA), 2001, 2003 (WARPS) and 2005 (SVALEX) will also be used.
The complex-instrumented buoys (will gather data on mean quantities and turbulent fluxes.
The complex-instrumented ice-tethered platforms (see “Clouds, radiative fluxes and surface albedo”) will gather data on wind, air temperature and air humidity.
Air-ice interaction, mixing in the stably stratified ABL, and interaction of the ABL and the free atmosphere will be studied by using process-oriented models being initialized on the basis of observed data and run with different horizontal and vertical resolutions.
The NWP model system HIRLAM will be improved with respect to stability in the planetary boundary layer.
The interaction of the Arctic ABL with leads, polynyas and thin ice will be studied. High-resolution remote sensing data on sea ice concentration (deliverable from core theme 1), ABL data and mesoscale models will be utilized to study (i) the sensitivity of the ABL on sea ice concentration and surface geometry and (ii) the effect of the atmospheric forcing on the sea ice drift, concentration, and thickness distribution (collaboration with core theme 1).
As results, we expect an improved knowledge on the structure of and processes in the Arctic AB and improved parameterization schemes for the exchange processes between the atmosphere and sea ice as well as between the atmosphere and the open ocean (applicable in core themes 1, 3, and 4).
