Field observations on board HALO
The research aircraft HALO (High Altitude and Long Range Research Aircraft) provides an excellent combination of high flight altitude and long range for investigations of climate processes in the UTLS. IEK-7 substantially contributed to HALO missions such as TACTS (Transport and Composition in the UT/LMS), ACRIDICON-CHUVA (Tropical Deep Convective Clouds and Precipitation over Amazonia) , ML-Cirrus (Formation, Lifetime, Properties and Radiative Impact of Mid–Latitude Cirrus Clouds) , POLSTRACC (Polar Stratosphere in a Changing Climate), GW-LCYCLE (Gravity Wave Life-Cycle), ESA´s GWEX (gravity wave experiment, coordinated by IEK-7) , and SALSA (Seasonality of Air mass transport and origin in the Lowermost Stratosphere using the HALO Aircraft).
In 2017, theWISE mission (Wave-driven Isentropic Transport, coordinated by IEK-7 and the University of Mainz) will focus on the exchange of air masses between the tropical upper troposphere and the extratropical lowermost stratosphere, including effects of the Asian summer monsoon. Future plans include a HALO mission investigating the composition and transport of the UTLS in the southern hemisphere (SOUTHTRAC-DYN, coordinated by DLR-IAP and IEK-7 in cooperation with the University of Mainz).
The in-situ instrumentation for HALO includes an ice-water package consisting of the Lyman-α hygrometer FISH (Fast In-situ Stratospheric Hygrometer)  and NIXE-CAPS (New Ice Experiment – Cloud and Aerosol Particle Spectrometer), which also participated in COALESC. In particular, FISH is one of the most advanced and sensitive in-situ instruments world-wide for measuring water vapor in the UTLS. In 2011, IEK-7 was therefore invited by NASA to participate in the water vapor inter-comparison aircraft campaign MACPEX .
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