Rain footprints on C-band synthetic aperture radar images of the ocean - Revisited
Abstract
It is well known that rain leaves footprints on the sea surface that sometimes become visible on synthetic aperture radar (SAR) images. Rain cells can easily be detected on SAR images at all radar frequencies when they are associated with a downdraft pattern. But rain cells are not always associated with downdraft and rain can also occur in other forms, as stratified rain, rain bands, and squall lines. It turns out that radar signatures of rain at C-band are much more complex than at L- or X-band radar and that it is particularly difficult to identify unambiguously rain events on C-band SAR images acquired over the ocean. This is because C-band lies in the transition region where raindrops impinging onto the sea surface can increase (usually) or decrease the backscattered radar power and where volume scattering and attenuation by rain drops in the atmosphere are not always negligible (at very high rain rates). In order to get an insight into the physical mechanisms causing the C-band radar signatures of rain, we first revisit results obtained from historic laboratory and field experiments and multi-frequency/multi-polarization SAR data acquired during the SIR-C/X-SAR spaceshuttle mission in 1994. Then we analyze several C-band SAR imagesmore »
- Authors:
-
- Univ. of Hamburg, Hamburg (Germany). Inst. of Oceanography
- Nanjing Univ. of Information Science and Technology, Nanjing (China). School of Marine Sciences; Jiangsu Research Center for Ocean Survey and Technology, Nanjing (China)
- IFREMER, Plouzane (France). Laboratoire d'Oceanographie Spatiale
- Ocean Univ. of China, Qingdao (China). Ocean Remote Sensing Inst.
- Hong Kong Observatory, Tsim Sha Tsui (Hong Kong)
- Publication Date:
- Research Org.:
- Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). National Energy Research Scientific Computing Center (NERSC)
- Sponsoring Org.:
- USDOE
- OSTI Identifier:
- 1478754
- Resource Type:
- Accepted Manuscript
- Journal Name:
- Remote Sensing of Environment
- Additional Journal Information:
- Journal Volume: 187; Journal Issue: C; Journal ID: ISSN 0034-4257
- Publisher:
- Elsevier
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 54 ENVIRONMENTAL SCIENCES
Citation Formats
Alpers, Werner, Zhang, Biao, Mouche, Alexis, Zeng, Kan, and Chan, Pak Wai. Rain footprints on C-band synthetic aperture radar images of the ocean - Revisited. United States: N. p., 2016.
Web. doi:10.1016/j.rse.2016.10.015.
Alpers, Werner, Zhang, Biao, Mouche, Alexis, Zeng, Kan, & Chan, Pak Wai. Rain footprints on C-band synthetic aperture radar images of the ocean - Revisited. United States. https://doi.org/10.1016/j.rse.2016.10.015
Alpers, Werner, Zhang, Biao, Mouche, Alexis, Zeng, Kan, and Chan, Pak Wai. Thu .
"Rain footprints on C-band synthetic aperture radar images of the ocean - Revisited". United States. https://doi.org/10.1016/j.rse.2016.10.015. https://www.osti.gov/servlets/purl/1478754.
@article{osti_1478754,
title = {Rain footprints on C-band synthetic aperture radar images of the ocean - Revisited},
author = {Alpers, Werner and Zhang, Biao and Mouche, Alexis and Zeng, Kan and Chan, Pak Wai},
abstractNote = {It is well known that rain leaves footprints on the sea surface that sometimes become visible on synthetic aperture radar (SAR) images. Rain cells can easily be detected on SAR images at all radar frequencies when they are associated with a downdraft pattern. But rain cells are not always associated with downdraft and rain can also occur in other forms, as stratified rain, rain bands, and squall lines. It turns out that radar signatures of rain at C-band are much more complex than at L- or X-band radar and that it is particularly difficult to identify unambiguously rain events on C-band SAR images acquired over the ocean. This is because C-band lies in the transition region where raindrops impinging onto the sea surface can increase (usually) or decrease the backscattered radar power and where volume scattering and attenuation by rain drops in the atmosphere are not always negligible (at very high rain rates). In order to get an insight into the physical mechanisms causing the C-band radar signatures of rain, we first revisit results obtained from historic laboratory and field experiments and multi-frequency/multi-polarization SAR data acquired during the SIR-C/X-SAR spaceshuttle mission in 1994. Then we analyze several C-band SAR images acquired by the European satellites Envisat and Sentinel-1A, and the Canadian satellite Radarsat-2 and compare them, whenever possible, with quasi-coincident and collocated weather radar images. The observational data show that, at low to medium rain rates, the main physical mechanism causing C-band radar signatures of rain is Bragg scattering at ring waves generated by the rain drops impinging onto the sea surface, which increase the radar backscatter. However, areas of increased radar backscatter are often accompanied by adjacent areas of decreased radar backscatter, which is due to attenuation of the Bragg waves by turbulence also generated by the impinging rain drops. Furthermore, we present a full-polarimetric Radarsat-2 SAR image of a rain cell together with a polarimetric decomposition analysis, which shows that the C-band radar signature of a rain cell is caused by surface scattering. The observation show that radar signatures of rain cells often contain segments, where the co-polarized as well the cross-polarized radar backscatter are strongly enhanced, which indicates non-Bragg scattering contributions to the scattering process. Furthermore, the polarimetric decomposition analysis shows that the C-band radar signature of a rain cell is dominated by surface scattering. Possible mechanisms, like scattering at splash products, are discussed. Whether the normalized radar cross section (NRCS) due to rain is increased or decreased depends on rain rate, wind speed, incidence angle, and history of the rain event. At low to moderate wind speeds (< 10 ms- 1) and low to medium high rain rates (< 50 mm h- 1), the NRCS is usually increased by up to 8 dB, and at high wind speeds (> 10 m s- 1) and low to high rain rates (but < 50 mm h- 1), the NRCS is usually decreased by up to 3 dB.},
doi = {10.1016/j.rse.2016.10.015},
journal = {Remote Sensing of Environment},
number = C,
volume = 187,
place = {United States},
year = {Thu Dec 01 00:00:00 EST 2016},
month = {Thu Dec 01 00:00:00 EST 2016}
}
Web of Science
Works referenced in this record:
A northerly winter monsoon surge over the South China Sea studied by remote sensing and a numerical model
journal, July 2012
- Alpers, Werner; Wong, Wai Kin; Dagestad, Knut-Frode
- International Journal of Remote Sensing, Vol. 33, Issue 23
Study of a Wind Front over the Northern South China Sea Generated by the Freshening of the North-East Monsoon
journal, June 2015
- Alpers, Werner; Wong, Wai Kin; Dagestad, Knut-Frode
- Boundary-Layer Meteorology, Vol. 157, Issue 1
Origin of Storm Footprints on the Sea Seen by Synthetic Aperture Radar
journal, November 1994
- Atlas, D.
- Science, Vol. 266, Issue 5189
An analysis of scatterometer returns from a water surface agitated by artificial rain: evidence that ring-waves are the main feature
journal, August 1993
- Bliven, L. F.; Branger, H.; Sobieski, P.
- International Journal of Remote Sensing, Vol. 14, Issue 12
Rain generated ring-waves: Measurements and modelling for remote sensing
journal, January 1997
- Bliven, L. F.; Sobieski, P. W.; Craeye, C.
- International Journal of Remote Sensing, Vol. 18, Issue 1
Multi‐frequency scatterometer measurements on water surfaces agitated by artificial and natural rain
journal, January 2006
- Braun, N.; Gade, M.
- International Journal of Remote Sensing, Vol. 27, Issue 1
The effect of artificial rain on wave spectra and multi-polarisation X band radar backscatter
journal, January 2002
- Braun, N.; Gade, M.; Lange, P. A.
- International Journal of Remote Sensing, Vol. 23, Issue 20
Radar modeling of a boreal forest
journal, July 1991
- Chauhan, N. S.; Lang, R. H.; Ranson, K. J.
- IEEE Transactions on Geoscience and Remote Sensing, Vol. 29, Issue 4
A review of target decomposition theorems in radar polarimetry
journal, March 1996
- Cloude, S. R.; Pottier, E.
- IEEE Transactions on Geoscience and Remote Sensing, Vol. 34, Issue 2
An entropy based classification scheme for land applications of polarimetric SAR
journal, January 1997
- Cloude, S. R.; Pottier, E.
- IEEE Transactions on Geoscience and Remote Sensing, Vol. 35, Issue 1
Effects of rain on Ku-band backscatter from the ocean
journal, January 2003
- Contreras, Robert F.
- Journal of Geophysical Research, Vol. 108, Issue C5
Assessment of Atmospheric Propagation Effects in SAR Images
journal, October 2009
- Danklmayer, A.; Doring, B. J.; Schwerdt, M.
- IEEE Transactions on Geoscience and Remote Sensing, Vol. 47, Issue 10
Modeling and observation of the radar polarization signature of forested areas
journal, May 1989
- Durden, S. L.; van Zyl, J. J.; Zebker, H. A.
- IEEE Transactions on Geoscience and Remote Sensing, Vol. 27, Issue 3
SIR-C/X-SAR observations of rain storms
journal, February 1997
- Jameson, Arthur R.; Li, Fuk K.; Durden, Stephen L.
- Remote Sensing of Environment, Vol. 59, Issue 2
The SIR-C/X-SAR Synthetic Aperture Radar system
journal, July 1995
- Jordan, R. L.; Huneycutt, B. L.; Werner, M.
- IEEE Transactions on Geoscience and Remote Sensing, Vol. 33, Issue 4
A semiempirical model of the normalized radar cross-section of the sea surface 1. Background model
journal, January 2003
- Kudryavtsev, Vladimir
- Journal of Geophysical Research, Vol. 108, Issue C3
Drop size effects on rain-generated ring-waves with a view to remote sensing applications
journal, January 2002
- Lemaire, D.; Bliven, L. F.; Craeye, C.
- International Journal of Remote Sensing, Vol. 23, Issue 12
An ERS-1 synthetic aperture radar image of a tropical squall line compared with weather radar data
journal, May 2001
- Lin, I. -I.; Alpers, W.; Khoo, V.
- IEEE Transactions on Geoscience and Remote Sensing, Vol. 39, Issue 5
The Distribution of Raindrops with size
journal, August 1948
- Marshall, J. S.; Palmer, W. Mc K.
- Journal of Meteorology, Vol. 5, Issue 4
SAR Polarimetry to Observe Oil Spills
journal, February 2007
- Migliaccio, Maurizio; Gambardella, Attilio; Tranfaglia, Massimo
- IEEE Transactions on Geoscience and Remote Sensing, Vol. 45, Issue 2
On the co‐polarized phase difference for oil spill observation
journal, March 2009
- Migliaccio, M.; Nunziata, F.; Gambardella, A.
- International Journal of Remote Sensing, Vol. 30, Issue 6
A simplified asymptotic theory for ocean surface electromagnetic wave scattering
journal, June 2007
- Mouche, A. A.; Chapron, B.; Reul, N.
- Waves in Random and Complex Media, Vol. 17, Issue 3
A C-Band Wind/Rain Backscatter Model
journal, March 2007
- Nie, Congling; Long, David G.
- IEEE Transactions on Geoscience and Remote Sensing, Vol. 45, Issue 3
Rain Effects on ASCAT-Retrieved Winds: Toward an Improved Quality Control
journal, July 2012
- Portabella, Marcos; Stoffelen, Ad; Lin, Wenming
- IEEE Transactions on Geoscience and Remote Sensing, Vol. 50, Issue 7
Characterization of Marine Surface Slicks by Radarsat-2 Multipolarization Features
journal, September 2014
- Skrunes, Stine; Brekke, Camilla; Eltoft, Torbjorn
- IEEE Transactions on Geoscience and Remote Sensing, Vol. 52, Issue 9
Scatterometry of a drop impact on a salt water surface
journal, September 1995
- Sobieski, P. W.; Bliven, L. F.
- International Journal of Remote Sensing, Vol. 16, Issue 14
Scatterometer data interpretation: Estimation and validation of the transfer function CMOD4
journal, March 1997
- Stoffelen, Ad; Anderson, David
- Journal of Geophysical Research: Oceans, Vol. 102, Issue C3
C-Band Cross-Polarization Wind Speed Retrieval
journal, May 2011
- Vachon, Paris W.; Wolfe, John
- IEEE Geoscience and Remote Sensing Letters, Vol. 8, Issue 3
Theories for the interaction of electromagnetic and oceanic waves ? A review
journal, January 1978
- Valenzuela, Gaspar R.
- Boundary-Layer Meteorology, Vol. 13, Issue 1-4
Theoretical model for scattering of radar signals in K u - and C-bands from a rough sea surface with breaking waves
journal, July 2001
- Voronovich, A. G.; Zavorotny, V. U.
- Waves in Random Media, Vol. 11, Issue 3
Measurements of the Effect of Rain-Induced Sea Surface Roughness on the QuikSCAT Scatterometer Radar Cross Section
journal, October 2008
- Weissman, David E.; Bourassa, Mark A.
- IEEE Transactions on Geoscience and Remote Sensing, Vol. 46, Issue 10
The Influence of Rainfall on Scatterometer Backscatter Within Tropical Cyclone Environments—Implications on Parameterization of Sea-Surface Stress
journal, December 2011
- Weissman, D. E.; Bourassa, M. A.
- IEEE Transactions on Geoscience and Remote Sensing, Vol. 49, Issue 12
On the theory of electromagnetic scattering from a raindrop splash
journal, November 1990
- Wetzel, L. B.
- Radio Science, Vol. 25, Issue 6
Surface layer response to weak winds, westerly bursts, and rain squalls in the western Pacific warm pool
journal, January 1996
- Wijesekera, Hemantha W.; Gregg, Michael C.
- Journal of Geophysical Research: Oceans, Vol. 101, Issue C1
A Backscattering Model of Rainfall Over Rough Sea Surface for Synthetic Aperture Radar
journal, June 2015
- Xu, Feng; Li, Xiaofeng; Wang, Peng
- IEEE Transactions on Geoscience and Remote Sensing, Vol. 53, Issue 6
Mapping sea surface oil slicks using RADARSAT-2 quad-polarization SAR image: MAPPING OIL SLICKS BY QUAD-POLARIZED SAR
journal, May 2011
- Zhang, Biao; Perrie, William; Li, Xiaofeng
- Geophysical Research Letters, Vol. 38, Issue 10
Study of a Wind Front over the Northern South China Sea Generated by the Freshening of the North-East Monsoon
journal, June 2015
- Alpers, Werner; Wong, Wai Kin; Dagestad, Knut-Frode
- Boundary-Layer Meteorology, Vol. 157, Issue 1
Simultaneous observations of rain cells over the ocean by the synthetic aperture radar aboard the ERS satellites and by surface-based weather radars
journal, March 2001
- Melsheimer, Christian; Alpers, Werner; Gade, Martin
- Journal of Geophysical Research: Oceans, Vol. 106, Issue C3
An improved composite surface model for the radar backscattering cross section of the ocean surface: 1. Theory of the model and optimization/validation by scatterometer data
journal, November 1997
- Romeiser, Roland; Alpers, Werner; Wismann, Volkmar
- Journal of Geophysical Research: Oceans, Vol. 102, Issue C11
Investigation of multifrequency/multipolarization radar signatures of rain cells over the ocean using SIR-C/X-SAR data
journal, August 1998
- Melsheimer, Christian; Alpers, Werner; Gade, Martin
- Journal of Geophysical Research: Oceans, Vol. 103, Issue C9
Drop size effects on rain-generated ring-waves with a view to remote sensing applications
journal, January 2002
- Lemaire, D.; Bliven, L. F.; Craeye, C.
- International Journal of Remote Sensing, Vol. 23, Issue 12
Rain generated ring-waves: Measurements and modelling for remote sensing
journal, January 1997
- Bliven, L. F.; Sobieski, P. W.; Craeye, C.
- International Journal of Remote Sensing, Vol. 18, Issue 1
Rain Identification in ASCAT Winds Using Singularity Analysis
journal, September 2014
- Lin, W.; Portabella, M.; Stoffelen, A.
- IEEE Geoscience and Remote Sensing Letters, Vol. 11, Issue 9
Polarimetric Analysis of Backscatter From the Deepwater Horizon Oil Spill Using L-Band Synthetic Aperture Radar
journal, October 2012
- Minchew, Brent; Jones, Cathleen E.; Holt, Benjamin
- IEEE Transactions on Geoscience and Remote Sensing, Vol. 50, Issue 10
ASCAT Wind Quality Control Near Rain
journal, August 2015
- Lin, Wenming; Portabella, Marcos; Stoffelen, Ad
- IEEE Transactions on Geoscience and Remote Sensing, Vol. 53, Issue 8
Works referencing / citing this record:
Detection of convective systems through surface wind gust estimation based on Sentinel-1 images: A new approach
journal, October 2018
- La, Tran Vu; Messager, Christophe; Honnorat, Marc
- Atmospheric Science Letters, Vol. 19, Issue 12
A labelled ocean SAR imagery dataset of ten geophysical phenomena from Sentinel‐1 wave mode
journal, July 2019
- Wang, Chen; Mouche, Alexis; Tandeo, Pierre
- Geoscience Data Journal, Vol. 6, Issue 2
Integrated Observations of Global Surface Winds, Currents, and Waves: Requirements and Challenges for the Next Decade
journal, July 2019
- Villas Bôas, Ana B.; Ardhuin, Fabrice; Ayet, Alex
- Frontiers in Marine Science, Vol. 6
A Study of the Intensity of Tropical Cyclone Idai Using Dual-Polarization Sentinel-1 Data
journal, November 2019
- Yu, Peng; Johannessen, Johnny A.; Yan, Xiao-Hai
- Remote Sensing, Vol. 11, Issue 23
Combining ASCAT and NEXRAD Retrieval Analysis to Explore Wind Features of Mesoscale Oceanic Systems
journal, September 2018
- Priftis, G.; Lang, T. J.; Chronis, T.
- Journal of Geophysical Research: Atmospheres, Vol. 123, Issue 18
Copolarized and Cross‐Polarized SAR Measurements for High‐Resolution Description of Major Hurricane Wind Structures: Application to Irma Category 5 Hurricane
journal, June 2019
- Mouche, Alexis; Chapron, Bertrand; Knaff, John
- Journal of Geophysical Research: Oceans, Vol. 124, Issue 6
Developing a Quality Index Associated with Rain for Hurricane Winds from SAR
journal, November 2018
- Shen, Hui; Seitz, Chana; Perrie, William
- Remote Sensing, Vol. 10, Issue 11
Estimation of Wind Direction in Tropical Cyclones Using C-Band Dual-Polarization Synthetic Aperture Radar
journal, February 2020
- Fan, Shengren; Zhang, Biao; Mouche, Alexis A.
- IEEE Transactions on Geoscience and Remote Sensing, Vol. 58, Issue 2
Integrated Observations of Global Surface Winds, Currents, and Waves: Requirements and Challenges for the Next Decade
journal, July 2019
- Villas Bôas, Ana B.; Ardhuin, Fabrice; Ayet, Alex
- Frontiers in Marine Science, Vol. 6