Measurements of sensible and latent heat and momentum flux within the boundary layer were acquired using an instrumented aircraft. The NOAA P3 research aircraft was instrumented with a specially modified NOAA Air Resources Laboratory 'Best Aircraft Turbulence' (BAT) probe to measure simultaneously the three-dimensional wind vector and ambient air temperature to near 1 m spatial resolution. This paper describes modifications and the overall evolution of the BAT probe from the pre-existing design that had been and continues to be used on small, single engine research aircraft to investigate turbulent fluxes in the atmospheric boundary layer under fair weather conditions.

The BAT probe, designed originally through a collaboration between NOAA/ARL and Airborne Research Australia (ARA), has flown on several aircraft since the early 1990's. The probe combines integrated pressure and temperature sensors, accelerometers and a GPS antenna/receiver in a single package that makes this instrument truly unique amongst airborne gust probes. As part of the Office of Naval Research (ONR) CBLAST-Hurricane initiative, a BAT probe was modified to operate on a NOAA P3 flying through hurricanes. Several iterations of the BAT probe occurred over a two-year period. Some of the changes/improvements to the original BAT probe design include: (1) an active back flush system to keep pneumatic lines clear of water when penetrating rainbands, (2) a passive drain system to prevent water from filling the larger design stagnation port, (3) a more robust machined aluminum hemisphere to replace the standard carbon-fiber hemisphere that was damaged in heavy rains at P3 flight speeds, (4) a more robust aluminum housing.