Wednesday night, 20th November, the last two radiosonde balloons of the SouthTRAC campaign were released from Rio Grande Airport.The SouhtTRAC team has started the preparations for the return to Germany.
It was decided to choose this clear night to coordinate the wind and temperature measurements of the radiosonde with the ground-based temperature measurements of CORAL. The first balloon was released at 9pm local time and the second one at midnight. It takes about one hour for the balloon to get up to 15 km altitude. This is the altitude where CORAL temperature measurements start; they reach up to 90 km altitude (the mesopause region).
Shortly after sunset, CORAL measurements were started by remote control from Germany. Usually, CORAL measures fully autonomous during night based on weather forecast data and local observations (weather station, all-sky camera, star detection). For this coordinated measurements, CORAL was remotely controlled to ensure that all is running as planned and to start the measurements a bit early than it’s usually the case. It was successful. Both balloon reached an altitude close to 30 km and lidar measurements were possible during the whole night.
In the meantime, teams here in Rio Grande are packing all their equipment that needs to be shipped back to Germany. Unfortunately, no more measurement flights were possible due to the technical issue that grounded the aircraft the last days. The aircraft will return to Oberpfaffenhofen within the next few days. The flight safety for HALO as well as the crew on board of the aircraft is not affected. Statements regarding the cause which led to the complications, can only be made after final inspections.