Title: Tomographic filtering of high-resolution mantle circulation models: Can seismic heterogeneity be explained by temperature alone?
Authors: B. S. A. Schuberth and H.-P. Bunge: Department of Earth and Environmental Sciences, Ludwig-Maximilians-Universitt Mnchen, Munich, Germany;
J. Ritsema: Department of Geological Science, University of Michigan, Ann Arbor, Michigan, USA.
Source: Geochemistry, Geophysics, Geosystems (G3) paper 10.1029/2009GC002401, 2009; http://dx.doi.org/10.1029/2009GC002401
9. New model shows how short-lived chemicals get to the stratosphere
The exchange of chemicals between the troposphere and the stratosphere can influence ozone production and longevity. For example, bromine compounds can turn into active forms that can efficiently deplete ozone if they are transported from the troposphere to the stratosphere through what is known as the tropical tropopause layer (TTL). To better understand how compounds are transported through the TTL, Gettelman et al. develop a model that simulates the effect of chemical reactions important to several short-lived compounds that pass through this region. Their model is one-dimensional, allowing complex processes to be reduced to a few simple relationships. The authors find that compounds that pass through the TTL with chemical lifetimes of 25 days or longer will have significant concentrations in the stratosphere and will be governed by vertical advection. By contrast, convection cycles govern the distribution of compounds with lifetimes of less than 25 days. This fundamental difference will help scientists understand the mechanics of how stratospheric ozone becomes depleted through interactions with these short-lived compounds.
Process regulating short-lived species in the tropical tropopause layer
|Contact: Maria-Jose Vinas|
American Geophysical Union