Observational evidence of moistening the lowermost stratosphere via isentropic mixing across the subtropical jet
<p>Isentropic mixing across and above the subtropical jet is a significant mechanism for stratosphere–troposphere exchange. In this work, we show new observational evidence on the role of this process in moistening the lowermost stratosphere. The new measurement, obtained from the Spatial Hete...
| Main Authors: | , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2020-05-01
|
| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://www.atmos-chem-phys.net/20/5477/2020/acp-20-5477-2020.pdf |
| Summary: | <p>Isentropic mixing across and above the subtropical jet is a
significant mechanism for stratosphere–troposphere exchange. In this work,
we show new observational evidence on the role of this process in moistening
the lowermost stratosphere. The new measurement, obtained from the Spatial
Heterodyne Observations of Water (SHOW) instrument during a demonstration
flight on the NASA's ER-2 high-altitude research aircraft, captured an event
of poleward water vapour transport,
including a fine-scale (vertically <span class="inline-formula"><i><</i>∼1</span> km) moist
filament above the local tropopause in a high-spatial-resolution
two-dimensional cross section of the water vapour distribution. Analysis of
these measurements combined with ERA5 reanalysis data reveals that this
poleward mixing of air with enhanced water vapour occurred in the region of
a double tropopause following a large Rossby wave-breaking event. These new
observations highlight the importance of high-resolution measurements in
resolving processes that are important to the lowermost-stratosphere
water vapour budget.</p> |
|---|---|
| ISSN: | 1680-7316 1680-7324 |