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Cite this paper: |
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Lihua WANG, Yanghua GAO, Peng LU, Li FAN, Yunxuan ZHOU. A new Doppler frequency anomaly algorithm for surface current measurement with SAR[J]. Journal of Oceanology and Limnology, 2022, 40(2): 470-484 |
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A new Doppler frequency anomaly algorithm for surface current measurement with SAR |
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| Lihua WANG1,2,3, Yanghua GAO3, Peng LU4, Li FAN3, Yunxuan ZHOU5 |
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1 Department of Geography and Spatial Information Techniques, Center for Land and Marine Spatial Utilization and Governance Research, Ningbo University, Ningbo 315211, China;
2 Institute of East China Sea, Ningbo University, Ningbo 315211, China;
3 Chongqing Institute of Meteorological Sciences, Chongqing 401147, China;
4 College of Geo-Exploration Science and Technology, Jilin University, Changchun 130026, China;
5 State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China |
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| Abstract: |
| Values for Doppler center frequency are calculated from the echo signal at the satellite using the Doppler centroid method and so include the predicted Doppler frequency caused by the relative motion of the satellite and the Earth, which is the main component of Doppler center frequency and must be removed to obtain the Doppler frequency anomaly for ocean current measurement. In this paper, a new Doppler frequency anomaly algorithm was proposed when measuring surface currents with synthetic aperture radar (SAR). The key of the proposed algorithm involved mean filtering method in the range direction and linear fitting in the azimuth direction to remove the radial and the azimuthal component of predicted Doppler frequency from the Doppler center frequency, respectively. The basis is that the theoretical Doppler center frequency model of SAR exhibits an approximately linear characteristic in both the range direction and in the azimuth direction. With the help of the new algorithm for predicted Doppler frequency removal, the estimation error of Doppler frequency anomaly can be reduced by avoiding employing the theoretical antenna pattern and imperfect satellite attitude parameters in the conventional Doppler frequency method. SAR measurement results demonstrated that, compared to the conventional Doppler frequency with/without error correction method, the proposed algorithm allows for a pronounced improvement in the current measuring accuracy in comparison with the global ocean multi-observation (MOB) products. In addition, the effectiveness and robustness of the proposed Doppler algorithm has been demonstrated by its application in the high velocity current in the Kuroshio region. |
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| Key words:
synthetic aperture radar (SAR)|Doppler frequency|Doppler frequency anomaly|current retrieval|ocean surface currents
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| Received: 2020-12-30 Revised: |
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References:
Ambe D, Imawaki S, Uchida H, Ichikawa K.2004.Estimating the Kuroshio axis south of Japan using combination of satellite altimetry and drifting buoys.Journal of Oceanography, 60(2):375-382, https://doi.org/10.1023/B:JOCE.0000038343.31468.fe.
Chapron B, Collard F, Ardhuin F.2005.Direct measurements of ocean surface velocity from space:interpretation and validation.Journal of Geophysical Research:Oceans, 110(C7):C07008, https://doi.org/10.1029/2004JC002809.
Chiri H, Abascal A J, Castanedo S, Antolínez J A A, Liu Y G, Weisberg R H, Medina R.2019.Statistical simulation of ocean current patterns using autoregressive logistic regression models:a case study in the Gulf of Mexico.Ocean Modelling, 136:1-12, https://doi.org/10.1016/j.ocemod.2019.02.010.
Cumming I G and Wong F H C.2005.Digital Processing of Synthetic Aperture Radar Data:Algorithms and Implementation.Artech House, Boston.p.82-94.Danilo C, Chapron B, Mouche A, Garello R, Collard F.2007.
Comparisons between HF radar and SAR current measurements in the Iroise Sea.In:IEEE Oceans 2007-Europe.IEEE, Aberdeen, UK.p.1-5, https://doi.org/10.1109/OCEANSE.2007.4302424.
Deng L J, Wei H, Wang J N.2015.Vertical distribution of the Kuroshio velocity in the pollution Nagasaki section and its formative mechanism.Marine Science Bulletin, 17(1):26-39.
Geng Y, Wang Q, Mu M.2018.Effect of the decadal Kuroshio extension variability on the seasonal changes of the mixedlayer salinity anomalies in the Kuroshio-Oyashio confluence region.Journal of Geophysical Research:Oceans, 123(12):8849-8861, https://doi.org/10.1029/2018JC014139.
Goldstein R M, Zebker H A, Barnett T P.1989.Remote sensing of ocean currents.Science, 246(4935):1282-1285, https://doi.org/10.1126/science.246.4935.1282.
Guo X Y, Miyazawa Y, Yamagata T.2006.The Kuroshio onshore intrusion along the shelf break of the East China Sea:the origin of the Tsushima Warm Current.Journal of Physical Oceanography, 36(12):2205-2231, https://doi.org/10.1175/JPO2976.1.
Han S Z, Yang H, Xue W H, Wang X C.2017.The study of single station inverting the sea surface current by HF ground wave radar based on adjoint assimilation technology.Journal of Ocean University of China, 16(3):383-388, https://doi.org/10.1007/s11802-017-3189-8.
Hansen M W, Collard F, Dagestad K F, Johannessen J A, Fabry P, Chapron B.2011a.Retrieval of sea surface range velocities from Envisat ASAR Doppler centroid measurements.IEEE Transactions on Geoscience and Remote Sensing, 49(10):3582-3592, https://doi.org/10.1109/TGRS.2011.2153864.
Hansen M W, Johannessen J A, Dagestad K F, Collard F, Chapron B.2011b.Monitoring the surface inflow of Atlantic water to the Norwegian Sea using Envisat ASAR.Journal of Geophysical Research:Oceans, 116(C12):C12008, https://doi.org/10.1029/2011JC007375.
He Y J, Yang X B, Yi N, Liu B C.2020.Progress in sea surface current retrieval from spaceborne SAR measurements.
Journal of Nanjing University of Information Science and Technology (Natural Science Edition), 12(2):181-190, https://doi.org/10.13878/j.cnki.jnuist.2020.02.005. (in Chinese with English abstract)
Johannessen J A, Chapron B, Collard F, Kudryavtsev V, Mouche A, Akimov D, Dagestad K F.2008.Direct ocean surface velocity measurements from space:improved quantitative interpretation of Envisat ASAR observations.Geophysical Research Letters, 35(22):L22608, https://doi.org/10.1029/2008GL035709.
Klemas V.2012.Remote sensing of coastal and ocean currents:an overview.Journal of Coastal Research, 28(3):576-586, https://doi.org/10.2112/JCOASTRES-D-11-00197.1.
Kneller B, Buckee C.2000.The structure and fluid mechanics of turbidity currents:a review of some recent studies and their geological implications.Sedimentology, 47(S1):62-94, https://doi.org/10.1046/j.1365-3091.2000.047s1062.x.
Kudryavtsev V, Akimov D, Johannessen J, Chapron B.2005.On radar imaging of current features:1.Model and comparison with observations.Journal of Geophysical Research:Oceans, 110(C7):C07016, https://doi.org/10.1029/2004JC002505.
Kudryavtsev V, Hauser D, Caudal G, Chapron B.2003.A semiempirical model of the normalized radar crosssection of the sea surface 1.Background model.Journal of Geophysical Research:Oceans, 108(C3):8054, https://doi.org/10.1029/2001JC001003.
Liu B C, He Y J, Li Y K, Duan H Y, Song X.2019.A new azimuth ambiguity suppression algorithm for surface current measurement in coastal waters and rivers with along-track InSAR.IEEE Transactions on Geoscience and Remote Sensing, 57(6):3148-3165, https://doi.org/10.1109/TGRS.2018.2881958.
Madsen S N.1989.Estimating the Doppler centroid of SAR data.IEEE Transactions on Aerospace and Electronic Systems, 25(2):134-140, https://doi.org/10.1109/7.18675.
Martin A C H, Gommenginger C P, Quilfen Y.2018.Simultaneous ocean surface current and wind vectors retrieval with squinted SAR interferometry:geophysical inversion and performance assessment.Remote Sensing of Environment, 216:798-808, https://doi.org/10.1016/j.rse.2018.06.013.
Mouche A A, Collard F, Chapron B, Dagestad K F, Guitton G, Johannessen J A, Kerbaol V, Hansen M W.2012.On the use of Doppler shift for sea surface wind retrieval from SAR.IEEE Transactions on Geoscience and Remote Sensing, 50(7):2901-2909, https://doi.org/10.1109/TGRS.2011.2174998.
Nilsson C S, Tildesley P C.1995.Imaging of oceanic features by ERS 1 synthetic aperture radar.Journal of Geophysical Research:Oceans, 100(C1):953-967, https://doi.org/10.1029/94JC02556.
Purkis S, Klemas V.2011.Remote Sensing and Global Environmental Change.John Wiley & Sons Ltd., West Sussex, U.K.367p, https://doi.org/10.1002/9781118687659.
Qiu B, Chen S M, Klein P, Torres H, Wang J B, Fu L L, Menemenlis D.2020.Reconstructing upper-ocean vertical velocity field from sea surface height in the presence of unbalanced motion.Journal of Physical Oceanography, 50(1):55-79, https://doi.org/10.1175/JPO-D-19-0172.1.
Raney R K.1986.Doppler properties of radars in circular orbits.International Journal of Remote Sensing, 7(9):1153-1162, https://doi.org/10.1080/01431168608948916.
Ren Y Z, Li X M, Gao G P, Busche T E.2017.Derivation of sea surface tidal current from spaceborne SAR constellation data.IEEE Transactions on Geoscience and Remote Sensing, 55(6):3236-3247, https://doi.org/10.1109/TGRS.2017.2666086.
Rio M H, Mulet S, Picot N.2014.Beyond GOCE for the ocean circulation estimate:synergetic use of altimetry, gravimetry, and in situ data provides new insight into geostrophic and Ekman currents.Geophysical Research Letters, 41(24):8918-8925, https://doi.org/10.1002/2014GL061773.
Romeiser R, Suchandt S, Runge H, Steinbrecher U, Grunler S.2010.First analysis of TerraSAR-X along-track InSARderived current fields.IEEE Transactions on Geoscience and Remote Sensing, 48(2):820-829, https://doi.org/10.1109/TGRS.2009.2030885.
Rouault M J, Mouche A, Collard F, Johannessen J A, Chapron B.2010.Mapping the Agulhas Current from space:an assessment of ASAR surface current velocities.Journal of Geophysical Research:Oceans, 115(C10):C10026, https://doi.org/10.1029/2009JC006050.
Sparr T, Krane B.2003.Micro-Doppler analysis of vibrating targets in SAR.IEE Proceedings-Radar, Sonar and Navigation, 150(4):277-283, https://doi.org/10.1049/iprsn:20030697.
Toporkov J V, Brown G S.2000.Numerical simulations of scattering from time-varying, randomly rough surfaces.IEEE Transactions on Geoscience and Remote Sensing, 38(4):1616-1625, https://doi.org/10.1109/36.851961.
Toporkov J V, Brown G S.2002.Numerical study of the extended Kirchhoff approach and the lowest order small slope approximation for scattering from ocean-like surfaces:Doppler analysis.IEEE Transactions on Antennas and Propagation, 50(4):417-425, https://doi.org/10.1109/TAP.2002.1003376.
Wang L H, Zhou Y X, Ge J Z, Johannessen J A, Shen F.2014.Mapping sea surface velocities in the Changjiang coastal zone with advanced synthetic aperture radar.Acta Oceanologica Sinica, 33(11):141-149, https://doi.org/10.1007/s13131-014-0563-x.
Wang S Q.2005.Research on the Doppler Centroid Real-Time Estimation Technology of Space-Borne SAR.Graduate School of Chinese Academy of Sciences (Institute of Electronics), Beijing, China. (in Chinese with English abstract)
Wong F, Cumming I G.1996.A combined SAR Doppler centroid estimation scheme based upon signal phase.IEEE Transactions on Geoscience and Remote Sensing, 34(3):696-707, https://doi.org/10.1109/36.499749.
Yu M C.2006.Research on New Methods of Parameters Estimation and Signal Simulation for SAR.Tsinghua University, Beijing, China. (in Chinese with English abstract)
Zhao B J, Qi X Y, Song H J, Zhou H.2013.Analysis of effective slant range model accuracy based on Low-EarthOrbital (LEO) spaceborne SAR.35(1):56-62, https://doi.org/10.3724/SP.J.1146.2012.00647. (in Chinese with English abstract)
Zhuang Z P, Hui Z L, Yang G B, Zhao X H, Yuan Y L.2020.Principal-component estimates of the Kuroshio Current axis and path based on the mathematical verification between satellite altimeter and drifting buoy data.Acta Oceanologica Sinica, 39(1):14-24, https://doi.org/10.1007/s13131-019-1523-2.
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