 |
| Titel |
The EarthCARE Doppler radar: forward modelling and performance estimation |
| VerfasserIn |
Alessandro Battaglia, Simone Tanelli, Pavlos Kollias |
| Konferenz |
EGU General Assembly 2010
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250038761
|
|
|
|
|
|
| Zusammenfassung |
| The 94 GHz EarthCARE radar (expected to be launched within three years) will be the first
radar in space with Doppler capabilities. The retrieval of hydrometeor fall speeds and air
motions from the radar signal will be extremely challenging due to a variety of complications.
In EarthCARE configuration (height=395 km, beam-width=0.08-, PRF around 6000 Hz) the
following caveats have to be accounted for: a) the high satellite speed matched to the finite
antenna beam-width produces consistent Doppler fading (ÏDoppler - 3.25 m/s); b) Nyquist
Doppler interval ( 4.5 m/s) can introduce relevant folding; c) non uniform beam filling
conditions may cause biases in the mean Doppler velocity estimates; d) multiple
scattering widens the Doppler spectrum and de-correlate the signal from the real mean
velocity.
A forward Doppler radar simulator capable of accounting both for non uniform beam filling
conditions and multiple scattering enhancements has been coupled to an instrument
simulator in order to reproduce the signal at the antenna port. In this paper the
EarthCARE radar simulator has been applied to a variety of scenarios (convective rain,
drizzle, cirrus sedimentation). The performance of different standard Doppler moment
estimators is discussed for the three different situations. In convective scenarios
it will be utterly tough to extract useful velocity information from EarthCARE
observations. |
|
|
|
|
|
|