Atmosphere-surface exchange is dominated by turbulent fluxes. Measurements are traditionally taken using fixed sensors bolted to masts, buoys or ships, sampling in the surface layer of the planetary boundary layer. However, studies at meso-scale and smaller show this fails to deliver dependable data as there is no distinction between genuine dynamics and mere advection. The solution is an airborne platform flying at a fixed height above ground level with minimal vertical deviation, acting as a mobile turbulence mast.
Although simple in theory, there are practical problems operating aircraft within boundary layers that have inversions, or are over smooth water or snow. These 'shallow' boundary layers require turbulence measurements at heights of just 4m, requiring an extremely responsive sensing and control system. The project aims to assess the suitability of a variety of fixed- and rotary-wing platforms for the proposed boundary layer sampling mission, and to develop, test and implement a suitable sensing and control system. The system will ultimately be field tested and results compared with established boundary layer measurement techniques.