WJ Reburn (CCLRC Rutherford Appleton Lab.), R Siddans (CCLRC Rutherford Appleton Lab.), BJ Kerridge (CCLRC Rutherford Appleton Lab.), S Buhler (Institute of Environmental Physics, Bremen U), A von Engeln (Institute of Environmental Physics, Bremen U.), P Eriksson (Institute of Environmental Physics, Bremen U.), T Kuhn-Sander (Institute of Environmental Physics, Bremen U.), K Kunzi (Institute of Environmental Physics, Bremen U.), C Verdes (Institute of Environmental Physics, Bremen U.)