Dropsondes (mobile radiosondes) were launched by 5 mobile radiosonde teams. The launching sites were different from IOP to IOP. The positions are identical with the positions of the meteorological towers (imkmt1 to imkmt4). There have been no more than 4 teams operational on each IOP. The dropsondes are radiosonde-like systems. The maximum height is 12050 m above MSL. At this height, the sondes are separated from the balloon and then glide to the ground. Drop points are up to 70 kilometres apart from launching sites. For detailed information about the sites see supplement file and map.