Dr. Holger Vömel comes from the Meteorological Observatory in Lindenberg, Germany, where he has been Head of the GCOS Reference Upper Air Network (GRUAN) Lead Center. Before taking over at the GRUAN Lead Center, Holger was a research scientist at the University of Colorado and NOAA for many years. In his work there he has made excellent contributions to the understanding of stratospheric water vapor, tropical tropopause processes and the measurements of upper air trace gases. His past work also includes characterizing uncertainties of radiosondes and other in-situ measurements, which he considers essential elements in any observational program.