Retrieval of Cloud Fraction and Pressure from the Ozone Monitoring Instrument (OMI)
Pepijn Veefkind(1,1), Maarten Sneep(1), Piet Stammes(1) and Pieternel Levelt(1)
(1) KNMI, POBox 201, 3730 AE De Bilt, Netherlands
The Ozone Monitoring Instrument (OMI) is the Dutch-Finnish contribution to the NASA EOS-Aura platform, which was launched in July 2004. OMI is the first of a new generation of UV-Visible spaceborne spectrometers that use two dimensional detectors. These detectors enable OMI to measure atmospheric trace gases and aerosols over the entire Earth within a single day and with high spatial resolution (13 km by 24 km at nadir), which makes this instrument extremely suitable for tropospheric research.
For satellite remote sensing of the lower troposphere, clouds are often a limiting factor. As an example, for the retrieval of tropospheric NO2 from UV/VIS spectrometers, uncertainty in the cloud fraction and pressure contribute strongly to the error budget. To reduce this uncertainty accurate information on cloud properties is needed.
To support the retrieval of trace gases from the Ozone Monitoring Instrument (OMI) a new cloud retrieval algorithm has been developed. This algorithm uses the O2-O2 absorption band around 477 nm to derive an effective cloud fraction and cloud pressure. In this contribution this algorithm will be described and results will be presented. In addition, a future outlook will be given on how cloud correction can be further improved using new algorithms and new instrument characteristics.
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,