January 13, 2009

Cloud Rayleigh Pressure : Results

Cloud Rayleigh Pressure: Consistency

Histogram of the difference between the surface pressure (Psurface)
and the Rayleigh pressure (Prayleigh). Results of the class 1 (old) algorithm
appear in blue when results for the class-2 (new) algorithm appear in red.

The new (class-2) algorithm greatly reduces the number of pixels with too high values of Rayleigh pressure

Cloud Rayleigh Pressure: Angular consistency

Mean Rayleigh pressure variation with the viewing angle.

The Rayleigh pressure parameter exhibits "strange" angular behaviour:

    for near-nadir observations the pressure suddenly increase. This can be observed for pixels located in the middle of the slot (see blue arrows)
    for viewing angles greater than 50°, the retrieved rayleigh pressure can be very different for pixels located West or East of the slot. This leads to discontinuities between two successive overlapping orbits (see red arrow).
    Those no-explained angular effects are specific to POLDER-2 measurements: they don't appear for POLDER-1 Rayleigh pressure whatever used algorithm (class-1 or class-2).

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