Measurement of Neutral Winds and Gradients in the Lower Thermosphere with Multi-Point, Chemical-Release Sounding Rocket Payloads.

Abstract:

Sounding rocket payloads capable of deploying multi-point chemical releases provide a unique tool for investigating the properties of the lower thermosphere. This type of payload consists of a collection of sub-payloads that are propelled laterally out of the rocket during flight. Each contains a canister of liquid tracer (such as tri-methyl aluminum) which, after separating from the main rocket, is dispersed by explosive detonation. The result is a luminous "puff" that can be tracked by triangulation using images taken from several ground stations, producing wind vector velocities with typical uncertainties of just 1-2 m/s. A deployment of puffs throughout a 3-dimensional volume spanning approximately 100x100 km horizontally and from 100 to 180 km altitude, vertically, makes it possible to measure the height profiles of all nine first-order spatial gradients of the neutral wind vector in the lower thermosphere.