The Arctic atmospheric boundary layer (ABL) has been considered to be a statically stable environment generally inhibiting vertical exchange. However, recent field programs and modeling studies have shown that the ABL has a complicated structure involving generally quasi-persistent, thermal and kinematic features (e.g., surface-based mixed layers, low-level jets within the stable air above, and low-level stratus clouds and fog), and more transitory features and processes often related to the quasi-persistent features. These transitory features and processes may facilitate vertical exchange. Some of the structures and processes possibly related to vertical exchange include breaking gravity waves, cloud-top cooling, surface mixed layers, horizontal roll vortices, and propagating lead-induced "microfronts". Many of these transitory features and processes occur on time scales of an hour or less.

To facilitate linking changes in atmospheric properties and aerosol concentrations to ABL structures and processes, a suite of remote sensors were deployed on the Swedish icebreaker Oden and on the pack ice near the North Pole during the Arctic Ocean Expedition-2001 (AOE-2001) in July and August, 2001. This suite consisted of two Doppler sodars, a 915 MHz wind profiler, a scanning 5 mm radiometer, and an S-band radar. These sensors were chosen to obtain observations of the thermal, kinematic and turbulent structure in the lowest 400-1000 m of the ABL with temporal resolution of less than an hour. These instruments complement each other well, but also have a degree of redundancy. They also complement the radiosonde measurements obtained typically every 6-12 hours, the episodic measurements with a tethered balloon and kites, and the hourly surface data. This paper will discuss the characteristics of the remote sensors, the necessary data processing, and the data recovery to obtain useful data in this unique environment. Validation with radiosonde data and in-situ data from the tethered balloons and kites will be presented. Some examples of the remote-sensing data during selected stability regimes and transitions will also be presented.