Terry Deshler
University of Colorado Boulder, CO·Earth & Environmental Science
Air enters the stratosphere, the dry upper layer of the atmosphere, by passing slowly upward through a cold band roughly 14 to 18 kilometers above the tropics called the tropical tropopause layer (TTL). How cold and how moist air gets on the way through sets how much water vapor the stratosphere holds, which matters for climate and for the chemistry that affects ozone.
- Fields
Earth & Environmental Science
Physics
Engineering
- Topics
tropical tropopause layer
stratospheric water vapor
supersaturation
- Grants
- 1 known grant, through Jan 2027
What they work on
- Test how important supersaturation is in setting stratospheric humidity, using balloon-borne Vaisala RS41 and tunable diode laser moisture sensors that previously recorded relative humidities above 150% in the tropical tropopause layer.
- Determine whether atmospheric waves generate the thin cirrus ice layers of the tropical tropopause layer, using RACHuTS reeldown profiles with one-meter vertical resolution to resolve layers only about ten meters thick.
- Identify the nature of unexplained layers of 2 to 20 micron particles observed at humidities too low for ice formation, by flying LASP Particle Counters at 20 km where conditions are too warm and dry for ice clouds.
- Build and deploy five LASP Particle Counters and three RACHuTS profilers for the 2025 Strateole-2 deployment of long-duration constant-altitude balloons launched from the Seychelles, and release the data openly.
More about the research
Thin cirrus clouds form there, and atmospheric waves ripple through it. Measuring all of this requires instruments that can stay aloft at those altitudes for weeks. This award supports participation in Strateole-2, a campaign organized by the French space agency CNES and the Laboratory for Dynamic Meteorology at the University of Paris-Saclay, which uses balloons that float at constant altitude for up to three months after launch from the Seychelles, drifting around the equator near 18 or 20 kilometers.
Why it matters
How much water vapor crosses into the stratosphere influences climate and stratospheric chemistry, yet the processes setting it remain uncertain. Long-duration, meter-resolution measurements of humidity, temperature and particles in the tropical tropopause layer give modelers a rare dataset for testing those processes, and the data are to be made freely available. The balloon instruments themselves advance meteorological measurement techniques usable in other settings.
Known grants
From NIH and NSF research grants. Labs often have other funding we can't see.
Closest labs
James Anderson
Harvard University, MA·Earth & Environmental Science
Determine how much water vapor from the 2022 Hunga Tonga eruption remains in the stratosphere and how its spread over time, altitude and latitude reveals stratospheric air circulation.
Angel Adames-Corraliza
University of Wisconsin-Madison, WI·Earth & Environmental Science·Early-career
Test whether colder lower-stratospheric temperatures during the easterly QBO phase strengthen the MJO by promoting cirrus clouds and their infrared radiative feedback, using COSMIC, CALIPSO and MLS satellite data plus reanalyses.
Brentha Thurairajah
Virginia Polytechnic Institute and State University, VA·Earth & Environmental Science
Measure how much of the large-scale gravity wave activity in the thermosphere comes from the troposphere versus from sources above the stratosphere, using controlled SD-WACCM-X whole-atmosphere model simulations.
The school
University of Colorado Boulder: 36 labs on PI Pages, $718M a year on research, 447 research doctorates a year.
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