Hydration and dehydration at the tropical tropopause

by C. Schiller, J.-U. Grooß, P. Konopka, F. Plöger, F. H. Silva dos Santos, N. Spelten
Atmospheric Chemistry and Physics Discussions ()
Get full text at journal

Abstract

High-resolution water measurements from three tropical airborne missions in Northern Australia, Southern Brazil and West Africa in different seasons are analysed to study the transport and transformation of water in the tropical tropopause layer (TTL) and its impact on the stratosphere. The mean profiles are quite different according to the season and location of the campaigns, with lowest mixing ratios below 2 ppmv at the cold point tropopause during the Australian mission in November/December and high TTL mixing ratios during the African measurements in August. We present backward trajectory calculations considering freeze-drying of the air to the minimum saturation mixing ratio and initialised with climatological satellite data. This trajectory-based reconstruction of water agrees well with the observed H2O average profiles and therefore demonstrates that the water vapour set point in the TTL is primarily determined by the Lagrangian saturation history. Deep convection was found to moisten the TTL, in several events even above the cold point up to 420 K potential temperatures. However, our study does not provide evidence for a larger impact of these highly-localised events on global scales.

Cite this document (BETA)

Readership Statistics

19 Readers on Mendeley
by Discipline
 
 
 
by Academic Status
 
32% Ph.D. Student
 
32% Post Doc
 
11% Professor
by Country
 
11% United States
 
5% Switzerland
 
5% Australia

Sign up today - FREE

Mendeley saves you time finding and organizing research. Learn more

  • All your research in one place
  • Add and import papers easily
  • Access it anywhere, anytime

Start using Mendeley in seconds!

Sign up & Download

Already have an account? Sign in