CRISTA-NF - a Helium-cooled Infrared Telescope for the Atmosphere
From CRISTA to CRISTA-NF
CRyogenic Infrared Spectrometers and Telescopes for the Atmosphere (CRISTA) is a scientific instrument developed by the University of Wuppertal, which performed very successfully during two Space Shuttle flights in November 1994 and August 1997. During these measurement flights small scale structures in atmospheric trace gas distributions were observed with an unprecedented vertical resolution.
CRISTA combines a high temporal resolution with a very high vertical sampling of the atmosphere, which is perfectly suited for a deployment on an aircraft. An adaption of the measurement technique to an aircraft platform would enable the observation of small scale structures with even higher vertical and horizontal resolution. Such structures frequently occur in the upper troposphere and lower stratosphere (UTLS), a region with large impact on many atmospheric processes. Due to its maximum flight altitude of about 20 km the M55 Geophysica is an excellent platform for measurements in the UTLS.
In cooperation with the Research Center Juelich (IEK-7, formerly ICG-1) the main telescope of CRISTA was adapted to the structure of the research plane M55 Geophysica. That included a new design of a compact light-weight cryostat, the modification of the electronics, as well as the installation of a new instrument control and data acquisition system. So CRISTA became the new airborne instrument CRISTA-NF.
Using the M55-Geophysica as a scientific platform the CRISTA-NF telescope measures altitude profiles of different trace gases, which are important in the UTLS such as H2O, O3, N2O, and CFC-11, at once. Additionally, CRISTA-NF is able to detect clouds and in the case of polar stratospheric clouds (PSC) the measurements can be used to distinguish different PSC types. With a vertical sampling of 100 – 300 m in the altitude range from around 5 to 20 km CRISTA-NF is an excellent scientific instrument for exploration of the dynamics, the structure and the composition of the Upper Troposphere / Lower Stratosphere (UTLS) region.
