Article

Rainfall observation from X-band, space-borne, synthetic aperture radar

Natural Hazards and Earth System Sciences 01/2009;
Source: DOAJ

ABSTRACT Satellites carrying X-band Synthetic Aperture Radars (SAR) have recently been launched by several countries. These provide new opportunities to measure precipitation with higher spatial resolution than has heretofore been possible. Two algorithms to retrieve precipitation from such measurements over land have been developed, and the retrieved rainfall distributions were found to be consistent. A maritime rainfall distribution obtained from dual frequency (X and C-band) data was used to compute the Differential Polarized Phase Shift. The computed Differential Polarized Phase Shift compared well with the value measured from space. Finally, we show a comparison between a recent X-band SAR image of a precipitation distribution and an observation of the same rainfall from ground-based operational weather radar. Although no quantitative comparison of retrieved and conventional rainfall distributions could be made with the available data at this time, the results presented here point the way to such comparisons.

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    Article: Evidence of Rainfall Signatures on X-Band Synthetic Aperture Radar Imagery Over Land
    F.S. Marzano, S. Mori, J.A. Weinman
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    ABSTRACT: Five spaceborne X-band synthetic aperture radars (X-SARs) are nowadays operating, and several more will be launched in the coming years. These X-SAR sensors, able to image the Earth's surface at metric resolution, may provide a unique opportunity to measure rainfall over land with spatial resolution of about a few hundred meters due to the moving-target degradation effects. This work is devoted to experimentally demonstrate this X-SAR capability, which can also be exploited to correct synthetic aperture radar (SAR) imagery for rainfall attenuation effects. Several case studies, selected from TerraSAR-X (TSX) overpasses over Europe and the southern U.S. in 2008, are qualitatively analyzed in terms of rainfall signatures. Visual validation of these rainfall SAR signatures is carried out by using available data from ground-based weather radars. A detailed data analysis for the case study of Hurricane ??Gustav?? on September 2, 2008, is carried out to assess a quantitative correlation among X-SAR response and near-surface precipitation rain rate. Two simplified empirical inversion algorithms, based on statistical regression and probability matching, are developed to retrieve rain rate from TSX cross-track ground-range measurements. The TSX-retrieved rain fields are compared to those estimated from the Next Generation Weather Radar (NEXRAD) in Mobile (Alabama, U.S.), showing a root-mean-square error less than 15 mm/h and a correlation of about 0.7.
    IEEE Transactions on Geoscience and Remote Sensing 03/2010; · 2.89 Impact Factor
Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.

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Keywords

available data
 
comparisons
 
computed Differential Polarized Phase Shift
 
conventional rainfall distributions
 
countries
 
Differential Polarized Phase Shift
 
dual frequency
 
ground-based operational weather radar
 
higher spatial resolution
 
maritime rainfall distribution
 
measure precipitation
 
measurements
 
precipitation
 
precipitation distribution
 
provide new opportunities
 
rainfall
 
recent X-band SAR image
 
retrieved rainfall distributions
 
Satellites
 
X-band Synthetic Aperture Radars