High-resolution density and temperature profiling in the stratosphere using bi-chromatic scintillation measurements by GOMOS
Francis Dalaudier(1), Alain Hauchecorne(1), Viktoria Sofieva(2) and Erkki Kyrölä(2)
(1) Service d'Aéronomie, BP 3, 91371 Verrieres-le-Buisson CEDEX, France
(2) Finnish Meteorological Institute, Erik Palmenin aukio, 1, FIN-00101 Helsinki, Finland
The GOMOS instrument on board the Envisat satellite is equipped with two photometers sampling simultaneously the star flux at two wavelengths in low-absorption regions (~499 and ~675nm) with a frequency of 1 kHz. The intensity of light measured by the GOMOS photometers exhibit fluctuations that may exceed its regular value by several hundred percent. These fluctuations are called scintillation. They are caused by air density irregularities.
The bi-chromatic scintillations allow the determination of refractive angle, which is proportional to the time delay between the photometer signals. We present the measurement principle and inversion algorithms for reconstruction of high resolution density and temperature profiles (HRTP) in the stratosphere from scintillation measurements. This new approach allows temperature and density profiling with very good vertical resolution ~200 m and high accuracy ~1-3 K at altitudes 15-40 km. The best accuracy is achieved in vertical (in orbital plane) occultations. Validation results are also shown.
HRTP can be assimilated into atmospheric models, used in studies of stratospheric clouds and in analysis of internal gravity waves activity.
Keywords: ESA European
Space Agency - Agence spatiale europeenne,
observation de la terre, earth observation,
satellite remote sensing,
teledetection, geophysique, altimetrie, radar,
chimique atmospherique, geophysics, altimetry, radar,