Middle/Upper Atmosphere – Fieldwork (Past Research)
Launched in 2002 by the European Space Agency, the Sun-synchronous ENVISAT satellite orbits at an altitude of 800 km with a descending node at 1000 local time. With the overall mission objective of advancing our knowledge of all components of the Earth environment, ENVISAT plays host to a large number of instruments including; ASAR (Advanced Synthetic Aperture Radar), AATSR (Advanced Along Track Scanning Radiometer), MERIS (Medium-spectral Resolution Imaging Spectrometer), RA-2 (Radar Altimeter 2), MWR (Microwave radiometer), GOMOS (Global Ozone Monitoring by Occultation of Stars), MIPAS (Michelson Interferometer for Passive Atmospheric Sounding), SCIAMACHY (SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY), DORIS (Doppler Orbitography and Radio-positioning Integrated by Satellite) and LRR (Laser Retro-Reflector).
The SCIAMACHY instrument measures irradiance at wavelengths between 240 and 1700 nm (plus between 2000 and 2400 nm in selected regions), with a spectral resolution between 0.2 and 1.5 nm. The default observing mode employs limb-scanning from the troposphere to the mesosphere/lower thermosphere (MLT) (10-100 km) with a vertical resolution of ~3 km. In addition, scans are made up to 150 km every two weeks to better cover the MLT region.
Utilising SCIAMACHY data, work has started on modifying an existing retrieval scheme (Gumbel et al. 2007) based on optimal estimation theory, to produce the first global datasets of satellite-borne measurements for the Fe, Ca and K metal layers, in addition to extending the current Na dataset. These datasets will provide a unique way to validate the chemistry and physics of the NCAR Whole Atmosphere Community Climate Model (WACCM) as part of the NERC 4M project.