Vertical Air Profiler

The Vertical Air Profiler consists of an air sampler with associated sensor electronics carried aloft up to 3000 ft by a blimp. On the ground a winch, batteries, ground electronics, and laptop computer are used to remotely power and control the airborne instrument. This is another fine example that shows that an Amy Instrumentation Facility prototype instrument must also be a final production unit.

In this photo, the Shepson team deploys the blimp in Barrow, Alaska. The vertical air sampler hangs under the blimp as the winch raises and lowers it to different sampling altitudes. The shack is used by team members to view the laptop computer that remotely controls the air sampler and gathers data.

A smaller cooler mounted on top of the winch contains the electronics that convert the battery power to high AC voltage for transmission to the airborne system. The cooler also contains a microprocessor that controls the AC voltage and bridges the communications between a ground based laptop computer and the airborne instrumentation. The circuit boards were designed, built, tested, and programmed by Amy Facility members. The 100 MHz microprocessor was programmed in assembly language to run the real-time data acquisition, data communications, and instrument control required by the system. The off-the-shelf laptop runs a custom control program that runs under Windows and was written in Visual Basic. The laptop gathers data and sends commands to the system by communicating with the winch electronics through an RS-232 serial port.

The winch is one of the key pieces in the Vertical Air Profiler. The winch was custom designed to meet the requirements of frigid arctic temperatures (-40 degrees), reeling the blimp in and out under high wind conditions, non-polluting, and able to power the airborne instrumentation and itself for up 8 hours. We combine off-the-shelf components with custom designed ones to create one-of-kind instrumentation. The winch uses ordinary plastic picnic coolers to house the gel-cell batteries and keep them from freezing. The electric motor and primary gear drive for the winch is actually a bumper-mountable 4x4 truck winch.

Vertical Air Profiler Publications

Tackett, P. J., A. E. Cavender, et al. (2007). "A study of the vertical scale of halogen chemistry in the Arctic troposphere during Polar Sunrise at Barrow, Alaska." Journal of Geophysical Research-Atmospheres 112(D7).