| Volumes and Issues Contents of Issue 3 Special Issue |
www.hydrol-earth-syst-sci.net/15/859/2011/
doi:10.5194/hess-15-859-2011
© Author(s) 2011. This work is distributed
under the Creative Commons Attribution 3.0 License.
Potential of high-resolution detection and retrieval of precipitation fields from X-band spaceborne synthetic aperture radar over land
1Department of Information Engineering, Electronics and Telecommunications (DIET), Sapienza University of Rome, Via Eudossiana 18, 00184 Rome, Italy
2Center of Excellence CETEMPS, University of L'Aquila, L'Aquila, Italy
3Istituto Nazionale di Geofisica e Vulcanologia, Rome, Italy
4Department of Atmospheric Sciences, University of Washington, Seattle, Washington, USA
5Department of Electric and Information Engineering, University of L'Aquila, L'Aquila, Italy
Abstract. X-band Synthetic Aperture Radars (X-SARs), 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 few hundred meters, due to the atmospheric moving-target degradation effects. This capability has become very appealing due to the recent launch of several X-SAR satellites, even though several remote sensing issues are still open. This work is devoted to: (i) explore the potential of X-band high-resolution detection and retrieval of rainfall fields from space using X-SAR signal backscattering amplitude and interferometric phase; (ii) evaluate the effects of spatial resolution degradation by precipitation and inhomogeneous beam filling when comparing to other satellite-based sensors. Our X-SAR analysis of precipitation effects has been carried out using both a TerraSAR-X (TSX) case study of Hurricane "Gustav" in 2008 over Mississippi (USA) and a COSMO-SkyMed (CSK) X-SAR case study of orographic rainfall over Central Italy in 2009. For the TSX case study the near-surface rain rate has been retrieved from the normalized radar cross section by means of a modified regression empirical algorithm (MREA). A relatively simple method to account for the geometric effect of X-SAR observation on estimated rainfall rate and first-order volumetric effects has been developed and applied. The TSX-retrieved rain fields have been compared to those estimated from the Next Generation Weather Radar (NEXRAD) in Mobile (AL, USA). The rainfall detection capability of X-SAR has been tested on the CSK case study using the repeat-pass coherence response and qualitatively comparing its signature with ground-based Mt. Midia C-band radar in central Italy. A numerical simulator to represent the effect of the spatial resolution and the antenna pattern of TRMM satellite Precipitation Radar (PR) and Microwave Imager (TMI), using high-resolution TSX-retrieved rain images, has been also set up in order to evaluate the rainfall beam filling phenomenon. As expected, the spatial average can modify the statistics of the high-resolution precipitation fields, strongly reducing its dynamics in a way non-linearly dependent on the rain rate local average value.
Final Revised Paper (PDF, 3917 KB) Discussion Paper (HESSD) Special Issue
Citation: Marzano, F. S., Mori, S., Chini, M., Pulvirenti, L., Pierdicca, N., Montopoli, M., and Weinman, J. A.: Potential of high-resolution detection and retrieval of precipitation fields from X-band spaceborne synthetic aperture radar over land, Hydrol. Earth Syst. Sci., 15, 859-875, doi:10.5194/hess-15-859-2011, 2011. Bibtex EndNote Reference Manager XML
