Stratospheric Adiabatic Mixing Rates Derived From the Vertical Gradient of Age of Air
Name
JGR Atmospheres - 2021 - Linz - Stratospheric Adiabatic Mixing Rates Derived From the Vertical Gradient of Age of Air.pdf
Description
Published version
Size
1.02 MB
Format
Adobe PDF
Checksum (MD5)
a98a50bd10eac1a302aa3e53131fb19b
Author(s)
Linz, Marianna
Plumb, R Alan
Gupta, Aman
Gerber, Edwin P
Date Issued
October 13, 2021
Journal
Journal of Geophysical Research: Atmospheres
Publisher
American Geophysical Union
Citation
Linz, M., Plumb, R. A., Gupta, A., & Gerber, E. P. (2021). Stratospheric adiabatic mixing rates derived from the vertical gradient of age of air. Journal of Geophysical Research: Atmospheres, 126, e2021JD035199.
Version
Final published version
Abstract
The circulation of the stratosphere transports important trace gases, including ozone, and can be thought of as having a fast horizontal mixing component and a slow meridional overturning component. Measuring the strength of the circulation directly is not possible, and so it must be inferred from tracer measurements. Long‐lived trace gases can be related to the idealized tracer age of air, which describes how long an air parcel has been in the stratosphere. In this paper, we derive a quantitative relationship between the vertical gradient of age and the horizontal mixing between the tropics and the extratropics using a “leaky pipe” framework in isentropic coordinates. Mixing rates of air into and out of the tropics are related to the vertical gradient of age in the tropics and in the extratropics, respectively. The derivation is repeated with the hemispheres separated so that the vertical structure of the mixing in the two hemispheres can be compared directly. These theories are applied to output from an idealized model of the stratosphere and from a realistic chemistry‐climate model to test our assumptions and calculate the mixing rates in the models. We then perform a quantitative comparison of the mixing rates in the Northern and Southern hemispheres along with an examination of where such a separation is valid. Finally, we perform a very preliminary calculation of mixing efficiency with satellite data to demonstrate the use of the mixing metric to compare mixing in models and data.
MIT Department
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
Terms of Use
Creative Commons Attribution-NonCommercial
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1029/2021jd035199
