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Air-sea Interaction of Typhoon Sinlaku (2002) Simulated by the Canadian MC2 Model

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Advances in Atmospheric Sciences 2006年第4期23卷 521-530页

作者：任雪娟 William perrie Department of Atmospheric Sciences Nanjing University Bedford Institute of Oceanography P. O. Box 1006 DartmouthNSB2Y 4A2Canada

Three experiments for the simulation of typhoon Sinlaku （2002） over the western North Pacific are performed in this study by using the Canadian Mesoscale Compressible Community （MC2） atmospheric model. The objective of these simulations is to investigate the air-sea interaction during extreme weather conditions, and to determine the sensitivity of the typhoon evolution to the sea surface temperature （SST） cooling induced by the typhoon. It is shown from the three experiments that the surface heat fluxes have a substantial influence on the slow-moving cyclone over its lifetime. When the SST in the East China coastal ocean becomes 1℃ cooler in the simulation, less latent heat and sensible heat fluxes from the underlying ocean to the cyclone tend to reduce the typhoon intensity. The cyclone is weakened by 7 hPa at the time of its peak intensity. The SST cooling also has impacts on the vertical structure of the typhoon by weakening the warm core and drying the eye wall. With a finer horizontal resolution of （1/6）° × （1/6）°, the model produces higher surface wind, and therefore more surface heat fluxes are emitted from the ocean surface to the cyclone, in the finer-resolution MC2 grid compared with the relatively lower resolution of 0.25° × 0.25° MC2 grid.

关键词： typhoon air-sea interaction SST cooling MC2

Effective dielectric constant model of electromagnetic backscattering from stratified air–sea surface film–sea water medium

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Chinese Physics B 2017年第5期26卷 120-125页

作者：谢涛 William perrie 方贺赵立于文金何宜军 School of Marine Sciences Nanjing University of Information Science and Technology Nanjing 210044 China Jiangsu Engineering Technology Research Center of Marine Environment Detection Nanjing 210044 China Fisheries & Oceans Canada Bedford Institute of Oceanography Dartmouth Nova Scotia B2Y4A2 Canada

Studies of surface film medium on the sea surface are carried out in this paper for developing the technology to automatically detect and classify sea surface films, and an effective dielectric constant model of electromagnetic backscattering from a stratified air–ocean interface. Numerical results of the new model show the characteristics of effective dielectric constants for the air–sea surface film–sea water medium as follows. The effective dielectric constants decrease with increasing relative dielectric constants of the sea surface films. The effective dielectric constants decrease in horizontal polarization（abbr. HH polarization） and increase in VV vertical polarization（abbr. VV polarization） with increasing radar incident angle. Effective dielectric constants vary with relative sea surface film thickness as a cosinusoidal function of sea surface film thickness. Effective dielectric constant of VV polarization is larger than that of HH polarization. Two potential applications are found with our model, i.e., the retrieval of dielectric constants from the sea surface film, and the film thickness retrieval with our model. Our model has a highly significant influence on improving the technology related to the remote sensing of sea surface films.

关键词： dielectric retrieval constants automatically classify stratified ocean imaginary incident layered

Oil spill detection on the ocean surface using hybrid polarimetric SAR imagery

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Science China Earth Sciences 2016年第2期59卷 249-257页

作者： LI HaiYan perrie William ZHOU YuanZe HE YiJun Key Laboratory of Computational Geodynamics Chinese Academy of Sciences College of Earth Sciences University of Chinese Academy of Sciences Fisheries and Oceans Canada Bedford Institute of Oceanography School of Marine Sciences Nanjing University of Information Science and Technology

Hybrid-polarimetric SAR(synthetic aperture radar) is a new SAR mode, with relatively simple architecture, low cost, and wide swath, which will be carried by several Earth-observing systems from now to the near future. Here, we show how the second Stokes parameter of hybrid-polarimetric SAR can be employed to detect oil on the ocean surface using the classic well-known Otsu threshold methodology, in relation to contributions from different polarizations and dampening effects on backscatter intensity, neglecting the specific scattering mechanisms and oil types for an oil-covered surface. The detection methodology is demonstrated to be reliable in three example cases: oil-on-water experiments conducted by the Norwegian Clean Seas Association, natural oil seeps from the Gulf of Mexico, and observations from the Deep Water Horizon oil spill disaster in 2010.

关键词： Oil spill detection Hybrid polarization Compact polarimetric SAR Stokes parameters Otsu threshold

Numerical study of electromagnetic scattering from one-dimensional nonlinear fractal sea surface

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Chinese Physics B 2010年第2期19卷 234-239页

作者：谢涛何超 William perrie 旷海兰邹光辉陈伟 School of Information Engineering Wuhan University of Technology Bedford Institute of Oceanography B2Y 4A2DartmouthNSCanada

In recent years, linear fractal sea surface models have been developed for the sea surface in order to establish an electromagnetic backscattering model. Unfortunately, the sea surface is always nonlinear, particularly at high sea states. We present a nonlinear fractal sea surface model and derive an electromagnetic backscattering model. Using this model, we numerically calculate the normalized radar cross section （NRCS） of a nonlinear sea surface. Comparing the averaged NRCS between linear and nonlinear fractal models, we show that the NRCS of a linear fractal sea surface underestimates the NRCS of the real sea surface, especially for sea states with high fractal dimensions, and for dominant ocean surface gravity waves that are either very short or extremely long.

关键词： fractals nonlinearities sea surface electromagnetic scattering

The observed analysis on the wave spectra of Hurricane Juan (2003)

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Acta Oceanologica Sinica 2014年第11期33卷 112-122页

作者： XU Fumin BUI THI Thuy Duyen perrie Will Key Laboratory of Coastal Disaster and Defense Ministry of EducationCollege of HarbourCoastal and Offshore EngineeringHohai University Fisheries & Oceans Canada Bedford Institute of Oceanography

Hurricane Juan provides an excellent opportunity to probe into the detailed wave spectral patterns and spectral parameters of a hurricane system, with enough wave spectral observations around Juan＇s track in the deep ocean and shallow coastal water. In this study, Hurricane Juan and wave observation stations around Juan＇s track are introduced. Variations of wave composition are discussed and analyzed based on time series of one-dimensional frequency spectra, as well as wave steepness around Juan＇s track： before, during, and after Juan＇s passing. Wave spectral involvement is studied based on the observed one-dimensional spectra and two-dimensional spectra during the hurricane. The standardization method of the observed wave spectra during Hurricane Juan is discussed, and the standardized spectra show relatively conservative behavior, in spite of the huge variation in wave spectral energy, spectral peak, and peak frequency during this hurricane. Spectral widths＇ variation during Hurricane Juan are calculated and analyzed. A two-layer nesting WW3 model simulation is applied to simulate the one-dimensional and two-dimensional wave spectra, in order to examine WW3＇s ability in simulating detailed wave structure during Hurricane Juan.

关键词： Hurricane Juan wave spectra wave steepness spectral width WW3

A new modulation transfer function for ocean wave spectra retrieval from X-band marine radar imagery

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Chinese Journal of Oceanology and Limnology 2015年第5期33卷 1132-1141页

作者：陈忠彪张彪何宜军丘仲锋 perrie William Nanjing University of Information Science and Technology Bedford Institute of Oceanography

When imaging ocean surface waves by X-band marine radar, the radar backscatter from the sea surface is modulated by the long surface gravity waves. The modulation transfer function （MTF） comprises tilt, hydrodynamic, and shadowing modulations. A conventional linear MTF was derived using HH-polarized radar observations under conditions of deep water. In this study, we propose a new quadratic polynomial MTF based on W-polarized radar measurements taken from heterogeneous nearshore wave fields. This new MTF is obtained using a radar-observed image spectrum and in situ buoy-measured wave frequency spectrum. We validate the MTF by comparing peak and mean wave periods retrieved from X-band marine radar image sequences with those measured by the buoy. It is shown that the retrieval accuracies of peak and mean wave periods of the new MTF are better than the conventional MTF. The results also show that the bias and root mean square errors of the peak and mean wave periods of the new MTF are 0.05 and 0.88 s, and 0.32 and 0.53 s, respectively, while those of the conventional MTF are 0.61 and 0.98 s, and 1.39 and 1.48 s, respectively. Moreover, it is also shown that the retrieval results are insensitive to the coefficients in the proposed MTF.

关键词： X-band marine radar modulation transfer function ocean wave spectra

A new model to estimate significant wave heights with ERS-1/2 scatterometer data

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Chinese Journal of Oceanology and Limnology 2009年第1期27卷 112-116页

作者：过杰何宜军 William perrie 申辉储小青 Institute of Oceanology Chinese Academy of Sciences Key Laboratory of Ocean Circulation and Wave CAS Graduate School of the Chinese Academy of Sciences Bedford Institute of Oceanography

A new model is proposed to estimate the significant wave heights with ERS-1/2 scatterometer data. The results show that the relationship between wave parameters and radar backscattering cross section is similar to that between wind and the radar backscattering cross section. Therefore, the relationship between significant wave height and the radar backscattering cross section is established with a neural network algorithm, which is, if the average wave period is ≤7s, the root mean square of significant wave height retrieved from ERS-1/2 data is 0.51 m, or 0.72 m if it is >7s otherwise.

关键词： scatterometer significant wave height neural networks wind waves swell

Electromagnetic backscattering from one-dimensional drifting fractal sea surface Ⅱ：Electromagnetic backscattering model

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Chinese Physics B 2016年第6期25卷 214-219页

作者：谢涛 William perrie 赵尚卓方贺于文金何宜军 School of Marine Sciences Nanjing University of Information Science and Technology Nanjing 210044 China Jiangsu Engineering Technology Research Center of Marine Environment Detection Nanjing 210044 China Bedford Institute of Oceanography B2 Y 4A2 Dartmouth NS Canada

Sea surface current has a significant influence on electromagnetic（EM） backscattering signals and may constitute a dominant synthetic aperture radar（SAR） imaging mechanism. An effective EM backscattering model for a one-dimensional drifting fractal sea surface is presented in this paper. This model is used to simulate EM backscattering signals from the drifting sea surface. Numerical results show that ocean currents have a significant influence on EM backscattering signals from the sea surface. The normalized radar cross section（NRCS） discrepancies between the model for a coupled wavecurrent fractal sea surface and the model for an uncoupled fractal sea surface increase with the increase of incidence angle,as well as with increasing ocean currents. Ocean currents that are parallel to the direction of the wave can weaken the EM backscattering signal intensity, while the EM backscattering signal is intensified by ocean currents propagating oppositely to the wave direction. The model presented in this paper can be used to study the SAR imaging mechanism for a drifting sea surface.

关键词： fractal ocean current electromagnetic scattering normalized radar cross section(NRCS)

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Simulation of Typhoon-Driven Waves in the Yangtze Estuary with Multiple-Nested Wave Models

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China Ocean Engineering 2005年第4期19卷 613-624页

作者：徐福敏 will perrie 张君伦宋志尧 Bechara Toulany College of Ocean Engineering Hohai University Nanjing210098China Fisheries and Oceans Canada Bedford Institute of Oceanography DartmouthNova Scotia Canada

Typhoon-generated waves are simulated with two numerical wave models, the SWAN model for the coastal and Yangtze Estuary domain, nested within the WAVEWATCHIII （WW3） for the basin-scale East China Sea domain. Typhoon No. 8114 is chosen because it was very strong, and generated high waves in the Estuary. WW3 was implemented for the East China Sea coarse-resolution computational domain, to simulate the waves over a large spatial scale and provide boundary conditions for SWAN model simulations, implemented on a fine-resolution nested domain for the Yangtze Estuary area. The Takahashi wind model is applied to the simulation of the East China Sea scale （3-hourly） and Yangtze Estuary scale （1-hourly） winds. Simulations of significant wave heights in the East China Sea show that the highest waves are on the right side of the storm track, and maxima tend to occur at the eastern deep-water open boundary of the Yangtze Estuary. In the Yangtze Estuary, incoming swell is dominant over locally generated waves before the typhoon approaches the Estuary. As the typhoon approaches the Estuary, wind waves and swell coexist, and the wave direction is mainly influenced by the swell direction and the complex topography.

关键词： WW3 SWAN typhoon-generated waves East China Sea Yangtze Estuary Takahashi wind model 2 D wave spectra significant wave height