Here an impression from our daily morning walk to replace the battery of the FMI sodar. A beautiful sunrise, even decorated by a sun dog. Our IOP3 was terminated around 5 local time this night, as fog came in and caused considerable icing on the propellers, wings and sensors of our aircraft. A safe and responsible operation of the UAVs was no longer possible. Up to that point it was a good measurement night, with SUMO profiles every 3 hours and low level profiling by the three quadcopter systems at least once per hour. A first check of the ground based measurements also indicates that all systems were up and running throughout the night. We can also look forward to analyze another valuable data set.