Abstract
Air masses in the convective outflows of four large convective systems near Borneo Island in Malaysia were sampled in the height range 11–13 km within the frame of the SHIVA (Stratospheric Ozone: Halogen Impacts in a Varying Atmosphere) FP7 European project in November and December 2011. Correlated enhancements of CO, CH4 and the short‐lived halogen species (CH3I and CHBr3) were detected when the aircraft crossed the anvils of the four systems. These enhancements were interpreted as the fingerprint of vertical transport from the boundary layer by the convective updraft and then horizontal advection in the outflow. For the four observations, the fraction f of air from the boundary layer ranged between 15 and 67%, showing the variability in transport efficiency depending on the dynamics of the convective system.
Highlights
The composition of the tropical upper troposphere (UT) is affected by the efficiency of the convective transport of chemical species (Fueglistaler et al, 2009)
Observational campaigns can only address the transport into the UT on an event-like basis but they are of high interest because the convection parameterisation is a major source of uncertainty in chemistry transport models (Arteta et al, 2009; Hoyle et al, 2011)
We present airborne measurements for four mesoscale convective events indicating enhanced UT CO and CH4 volume mixing ratios that directly correlate with CHBr3 and CH3I enhancements when the aircraft passed the anvil of convective cumulus clouds
Summary
The composition of the tropical upper troposphere (UT) is affected by the efficiency of the convective transport of chemical species (Fueglistaler et al, 2009). Previous observational studies of convective outflows at mid-latitudes (Bertram et al, 2007) and in the tropics (Ray et al, 2004) reported an effective transport of short-lived trace gases (Cohan et al, 1999; Bechara et al, 2010) by.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
