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[atmos-physics]

[University of Wuppertal]


F. Olschewski [mailto]
last updated: 07. 03. 2007



CRISTA is a limb-scanning experiment that measures thermal emissions (4 - 71 µm) of selected trace gases with high spatial resolution in three dimensions.
By means of the measured limb radiance fields, dynamic structures of the atmosphere with small horizontal scales (300 km) can be resolved. The vertical resolution is in the order of 2 - 3 km.
 
Fig. 1 Viewing geometry of CRISTA

The CRISTA instrument is mounted on the ASTRO-SPAS platform (Fig. 1) which is released from the Shuttle and operates at a distance of 20 - 100 km behind the Shuttle. For improved horizontal resolution CRISTA uses three telescopes that sense the atmosphere simultaneously at angles 18° apart (Fig. 1 and 2). To achieve high measuring speed and, consequently, high spatial resolution along the track, the detectors and the optics of the instrument are cooled by cryogenic helium. The incoming limb radiance is analyzed by four grating spectrometers of the Ebert-Fastie type with a spectral resolving power of about 500.


Fig. 2 Cross sectional view of CRISTA


Fig. 3 Central telescope of CRISTA (concept)


Fig. 4 Central telescope of CRISTA


Fig. 5 CRISTA Electronics

see some images of CRISTA and CRISTA-SPAS