A New Versatile Dropsonde for Atmospheric Soundings with HALO – The KITsonde

Abstract. A new modular multi-sensor aerological dropsonde system for high and fast-flying research aircraft has been developed for studying atmospheric processes. This new system allows to drop release containers with up to 4 sondes inside and data from up to 30 sondes can be transmitted simultaneously. After separation from the release container, the sondes enable high-resolution spatio-temporal profiling of temperature, humidity, pressure, and wind with a time resolution of 1.2 s corresponding to approximately 10 m vertical resolution. The modular design ensures simple integration of additional sensors without extensive flight tests and recertification for e.g. particle measurements and radioactivity.

The standard meteorological sonde comprises sensor elements of a commercial Graw DFM-17 radiosonde, a 400 to 406 MHz band communication link to the aircraft, and an optional satellite communication module. By means of the satellite link, the data can be made ​​available worldwide in near real time and data loss is avoided when the dropping aircraft leaves the telemetry range.

The main feature of the new system is the release container, which allows for dropping through standard dropsonde dispensers of both mid-size turbo-prop aircraft (e.g. Dornier Do 128-6) and jet aircraft (e.g. the Gulfstream 550 “High Altitude and Long Range Research Aircraft, HALO”). The release container ensures safe separation from the aircraft and protects its payload during deceleration from aircraft speed to fall speed before the sondes are released by an electro-mechanical mechanism. Operations in different campaigns have confirmed the reliability of the entire system and the quality of acquired data. Feasibility of the technical and operational approach for targeted observations of a mesoscale convective system in Argentina was demonstrated by HALO measurements during the SouthTRAC (TRAnsport and Composition of the southern hemisphere UTLS campaign) campaign. Moreover, a configuration consisting of one meteorological sonde coupled (a) with an optical counter for particle sizing was tested using a Dornier Do 128-6 aircraft during a Saharan dust episode over Germany and (b) with a radioactivity sensor was successfully dropped from a Learjet 35A.