The COST 723 action

An overview is provided of the COST 723 Action, 'Data Exploitation and Modelling of the Upper Troposphere and Lower Stratosphere'. The three working groups are introduced and a summary of Action activities within them is provided. The achievements of the Action are: three international workshops; the LAUTLOS humidity measurement campaign; dedicated meetings to discuss the quality of upper troposphere/lower stratosphere ozone and humidity measurements; two journal special issues; more than 90 papers in the peer-reviewed literature; one international summer school; and a successor COST Action which builds on COST 723. The recommendations made are: for COST to continue to support the short-term scientific missions instrument, as they are perceived to be value for money; to encourage the use of COST money to increase links between COST Actions and other scientific communities; and for the COST secretariat to recommend that Actions consider a summer school instead of a final workshop or meeting.