Andreas Engel, (Co-I of P1, Partner of P2), Prof. Dr., the responsible scientist, has been involved in atmospheric research since 1990. He is an associate Professor at the University Frankfurt since 2010. He has a long standing experience in the observation of atmospheric trace gases from many different platforms (balloons, aircraft and stations) and has participated in and coordinated many national and international (funded by the EC) campaigns and projects. His scientific interests include stratospheric chemistry and dynamics with a special emphasis on long-term change of stratospheric composition. He is author or co-author of more than 60 peer reviewed publications and has authored or co-authored several European and International reports (e.g., WMO reports, 2nd Assessment report on European research in the stratosphere, EC report on ozone-climate interactions, currently lead author for the SPARC lifetime assessment report).