Quantifying the Stratospheric Circulation from Satellite Measurements
Abstract
The stratospheric circulation is important for transporting ozone and water vapor, which affect radiation and climate. The stratospheric circulation consists of a slow meridional overturning and a comparatively rapid horizontal mixing component. These have both been difficult to quantify from observations. We present a simplified framework that allows quantification of both the slow and fast components using the idealized tracer "age of air". Age is the time since an air parcel entered the stratosphere at the tropical tropopause. Although this is an idealized tracer, we can calculate it from observations from three satellite instruments (Microwave Limb Sounder, the Atmospheric Chemistry Experiment Fourier Transform Spectrometer, and the Michelson Interferometer for Passive Atmospheric Sounding) and in situ aircraft and balloon data. The strength of the overturning circulation at 460 K is 6.3-7.6 x10 9 kg/s, and the mixing efficiency is about 0.75, though the mixing efficiency is much more uncertain. We also show the average circulation strength in the different hemispheres and a preliminary time series. The time series is necessarily preliminary, since the recent in situ observations for calculating the tracer-tracer relationships do not exist. We highlight uncertainties and the need for specific new observations.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.A44F..04L
- Keywords:
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- 0340 Middle atmosphere: composition and chemistry;
- ATMOSPHERIC COMPOSITION AND STRUCTURE;
- 0341 Middle atmosphere: constituent transport and chemistry;
- ATMOSPHERIC COMPOSITION AND STRUCTURE;
- 0342 Middle atmosphere: energy deposition;
- ATMOSPHERIC COMPOSITION AND STRUCTURE;
- 0394 Instruments and techniques;
- ATMOSPHERIC COMPOSITION AND STRUCTURE