Overview of and first observations from the TILDAE High-Altitude Balloon Mission

Bennett A Maruca,David Sundkvist,Herb Zimmerman,Vincenzo Carbone,Raffaele Marino,Stephane Constantin,Niharika H Godbole

doi:10.5194/amt-10-1595-2017

Abstract

Abstract. Though the presence of intermittent turbulence in the stratosphere has been well established, much remains unknown about it. In situ observations of this phenomenon, which have provided the greatest details of it, have mostly been achieved via sounding balloons (i.e., small balloons which burst at peak altitude) carrying constant-temperature hot-wire anemometers (CTAs). The Turbulence and Intermittency Long-Duration Atmospheric Experiment (TILDAE) was developed to test a new paradigm for stratospheric observations. Rather than flying on a sounding balloon, TILDAE was incorporated as an add-on experiment to the payload of a NASA long-duration balloon mission that launched in January 2016 from McMurdo Station, Antarctica. Furthermore, TILDAE's key instrument was a sonic anemometer, which (relative to a CTA) provides better-calibrated measurements of wind velocity and a more robust separation of velocity components. During the balloon's ascent, TILDAE's sonic anemometer provided atmospheric measurements up to an altitude of about 18 km, beyond which the ambient air pressure was too low for the instrument to function properly. Efforts are currently underway to scientifically analyze these observations of small-scale fluctuations in the troposphere, tropopause, and stratosphere and to develop strategies for increasing the maximum operating altitude of the sonic anemometer.

Highlights

The Turbulence and Intermittency Long-Duration Atmospheric Experiment
While it had been hoped that Turbulence and Intermittency Long-Duration Atmospheric Experiment (TILDAE) would collect measurements during the balloon’s “float” phase, the ascent-phase measurements have provided scientifically useful observations of the tropopause and the lower stratosphere
– The dissipation rate of kinetic energy provides an important diagnostic for characterizing any turbulent phenomenon. Using techniques such as those developed by Theuerkauf et al (2011) for single-point balloon measurements, dissipation rates will be inferred for various periods in the TILDAE dataset

Summary

Introduction

The Turbulence and Intermittency Long-Duration Atmospheric Experiment A. Maruca) was developed to make high-cadence in situ measurements of the stratosphere’s velocity fields. As detailed below, this type of device measures the transit time of ultrasonic pulses through the air. This type of device measures the transit time of ultrasonic pulses through the air This techniques provides wellcalibrated measurements of the wind velocity and of the air’s sound speed (and temperature)

Results

Discussion

Conclusion