Institute of Meteorology and Climate Research

Instruments

We use satellite measurements to infer the atmospheric composition relevant to our work and for the evaluation of climate models. The European research satellite ENVISAT hosts the two main instruments MIPAS and SCIAMACHY. They are in a sun-synchronous orbit since 2002, at about 800 km altitude. ENVISAT is flying along the 10:00 and 22:00 local solar time line with an orbital period of about 100 minutes. In April 2012 the communication to the satellite was lost, but we have an almost daily global data set over ten years of atmospheric spectra.

The SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY) is a spectrometer with eight channels ranging from the UV (230 nm) to the visible range to the near infrared (2300 nm) with a resolution from 0.22 nm to 0.54 nm, but also 1.5 nm in one channel.

The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) range from 4150 nm to 14600 nm with a resolution from 0.11 nm to 1.33 nm. Both instruments' field of view are directed along the flight path, SCIAMACHY "looking" forward, and MIPAS scanning the backward direction. The orientation of the instruments allows us to validate the measurements against each other.

Both MIPAS and SCIAMACHY feature a measurement mode that scans the mesosphere and lower thermosphere (50...150 km), but in sparsely sampled time intervals. The MIPAS upper atmosphere (UA) mode was scheduled every 10 days, and the SCIAMACHY mesosphere and lower thermosphere (MLT) mode was scheduled every two weeks. This schedule, however, allowed simultaneous measurements of the middle atmosphere with both instruments once a month.

First results include the nitric oxide (NO) number density in the middle atmosphere from the SCIAMACHY UV spectra using the NO gamma bands. We achieve a vertical resolution of about 5 to 10 km and our results are in line with the results from MIPAS and from other instruments measuring the NO density in that atmospheric region.