Science Seminars

Stratéole 2: Detailed Measurements of the Tropical Tropopause Layer from Constellations of Long Duration Super Pressure Balloons

Speaker: Lars Kalnajs (LASP)
Date: Thursday, Nov 30, 2017
Time: 4:00 PM
Location: SPSC W120

Seminar Abstract:

The Tropical Tropopause Layer (TTL) is the gateway for air to enter the global upper atmosphere, thorough a gradual upwelling from the tropical troposphere, punctuated by deep convection. The conditions in the TTL set the boundary conditions for the global distribution of stratospheric water vapor, aerosols and ozone, all of which have a significant impact on climate. The Brewer-Dobson circulation in the stratosphere and the time varying Quasi Biennial Oscillation of stratospheric winds are both driven by dynamical wave driven processes that originate in or transit through the TTL. Understanding the chemical and dynamical processes in the TTL is critical to our understanding of the global atmosphere. Yet, due to a variety of challenges, the TTL is still one of the more poorly observed regions of the atmosphere and the fine scale processes within the TTL are inadequately resolved in general circulation models. Stratéole 2 presents an entirely new paradigm for collecting high resolution in situ measurements of the TTL using constellations of ultra long duration super pressure balloons that will circumnavigate the globe at the top edge of the TTL. At LASP we are developing three new types of highly specialized instrumentation to probe the TTL from these CubeSat like platforms – a deployable fiber optic temperature profiler, a tethered water vapor, cloud, aerosol and temperature profiling package and an optical particle counter for measuring stratospheric aerosol size distributions. The profile measurements of temperature, water vapor and clouds will give a remarkably detailed view of wave dynamics, dehydration processes and cloud formation in the TTL while providing far more in situ observations in the TTL than all prior measurements combined. I will talk about the scientific questions that Stratéole 2 is designed to address, describe the physics and techniques behind super pressure ballooning and the Stratéole 2 platform, and explain how the new instruments we have developed will help answer these outstanding questions.