Lagrangian Balloon for Atmospheric Research

University Of Massachusetts Amherst, Amherst MA

Investigators

Abstract

This grant supports the design, construction, and testing of a balloon for atmospheric sounding that has an active buoyancy control to enable it to move with the wind. By faithfully tracking the air motions, it provides a so-called Lagrangian frame of reference for measurements of temperature, pressure, humidity, ozone, and other trace gases. These measurements are needed to observe the histories of air parcels as they undergo photochemical and cloud physical processes in the high atmosphere. For example, important details in the formation of polar stratospheric clouds are lacking because the temperature histories of the air parcels in which these clouds form are not known with sufficient accuracy. Moreover, uncertainties in air parcel motion in the tropics mask the mechanism by which water vapor enters the stratosphere, confounding attempts to predict how the ozone layer will respond to climate change. The Lagrangian balloon is of "pumpkin" design, nine meters in diameter, equipped with an interior servomechanism to change its volume in response to vertical air motions relative to the balloon. The buoyancy is continually adjusted to minimize the vertical air motion, so that the balloon tracks the air with a relative velocity held as near to zero as possible. The balloon can carry a light payload of instruments for measuring the vertical air velocity relative to the balloon, thermodynamic variables, and a satellite modem for communicating with the ground. Students from the University of Massachusetts and the Picker Engineering Program at Smith College will participate in the project.