English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

During the second part of theTROCCINOX campaign that took place in Brazil in early 2005,chemical species were measured on-board the high-altitude research aircraftGeophysica (ozone, water vapor, NO, NO<sub>y</sub>, CH<sub>4</sub> and CO)in the altitude range up to 20 km (or up to 450 K potential temperature),i.e. spanning the entire TTL region roughly extendingbetween 350 and 420 K.  Here, analysis of transport across the TTL is performedusing a new version of theChemical Lagrangian Model of the Stratosphere (CLaMS). In this newversion, the stratospheric model has been extended to the earth surface.Above the tropopause, the isentropic and cross-isentropic advection in CLaMSis driven by meteorological analysis windsand heating/cooling rates derived from a radiation calculation.Below the tropopause, the model smoothly transforms from the isentropic tothe hybrid-pressure coordinate and, in this way, takes into account theeffect of large-scale convective transportas implemented in the vertical wind of the meteorological analysis.As in previous CLaMS simulations, the irreversible transport, i.e. mixing,is controlled by the local horizontal strain and vertical shear rates.  Stratospheric and tropospheric signatures in the TTL canbe seen both in the observations and in the model.The composition of air above ≈350 K is mainly controlledby mixing on a time scale of weeks or even months. Based onCLaMS transport studies where mixing can be completely switchedoff, we deduce that vertical mixing, mainly driven by the vertical shear inthe tropical flanks of the subtropical jets and, to some extent, in thethe outflow regions of the large-scale convection, offers anexplanation for the upward transport of trace speciesfrom the main convective outflow at around 350 K up to the tropicaltropopause around 380 K

Contribution of mixing to upward transport across the tropical tropopause layer (TTL)