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Buchwaldoboletus xylophilus and Phlebopus portentosus (Boletales) are two non-ectomycorrhizal boletes, which are widely reported in tropical Asia. However, there is little information available about the taxonomy of these two boletes. Here, B. xylophilus and P. portentosus are redescribed based on morphology and molecular phylogenetic analyses of DNA sequences from nuclear 28S rDNA (28S), nuc rDNA internal transcribed spacer region ITS1-5.8S-ITS2 (ITS), translation elongation factor 1-α gene (TEF1) and the RNA polymerase II second largest subunit gene (RPB2). Detailed descriptions, color photos of fresh basidiomata, and line-drawings of microscopic features of the two taxa are presented.

Ketocarotenoids were synthesized successfully in Camelina sativa seeds by genetic modification without using a traditional selection marker genes. This method provided an interesting tool for metabolic engineering of seed crops. Camelina sativa (L.) Crantz is an important oil crop with many excellent agronomic traits. This model oil plant has been exploited to accumulate value-added bioproducts using genetic manipulation that depends on antibiotic- or herbicide-based selection marker genes (SMG), one of the major concerns for genetically modified foods. Here we reported metabolic engineering of C. sativa to synthesize red ketocarotenoids that could serve as a reporter to visualize transgenic events without using a traditional SMG. Overexpression of a non-native β-carotene ketolase gene coupled with three other carotenogenous genes (phytoene synthase, β-carotene hydroxylase, and Orange) in C. sativa resulted in production of red seeds that were visibly distinguishable from the normal yellow ones. Constitutive expression of the transgenes led to delayed plant development and seed germination. In contrast, seed-specific transformants demonstrated normal growth and seed germination despite the accumulation of up to 70-fold the level of carotenoids in the seeds compared to the controls, including significant amounts of astaxanthin and keto-lutein. As a result, the transgenic seed oils exhibited much higher antioxidant activity. No significant changes were found in the profiles of fatty acids between transgenic and control seeds. This study provided an interesting tool for metabolic engineering of seed crops without using a disputed SMG.

Hydrochemistry is an important parameter for wetland water environmental assessment. To study the hydrochemistry and main ion sources in the Qilihai wetland in Tianjin, river water, groundwater, and water in the marsh were collected and analyzed. The results show that:① The river and marsh waters are SO

Since the outbreak of a large-scale Ulva prolifera bloom in the Yellow Sea during the Qingdao Olympic Sailing Competition in summer 2008, Ulva blooms have been a marine hazard every summer. Accurate and timely information on Ulva areal coverage and biomass is of critical importance for governmental responses, decision making, and field studies. Previous studies have shown that satellite remote sensing is the most effective method for this purpose, yet Ulva areal coverage has been estimated in different ways with significantly different results. The objective of this paper is to determine the lower and upper bounds (T0 and T1) of algae-containing pixels in Floating Algae Index images with an objective method that accurately estimates the Ulva areal coverage in individual images, and then converts coverage to biomass using a previously established conversion equation. First, a seawater background image, FAIsw, is constructed to determine T0, which varies for different algae patches. Then, T1 is determined from water tank and in situ measurements as well as radiative transfer simulations to account for different sensor configurations, solar/viewing geometry, and atmospheric conditions. Such determined T1 for MODIS 250-m resolution data is validated using concurrent and collocated 2-m resolution WorldView-2 data. Finally, Ulva areal coverage derived from MODIS data using this method are compared with those from the high-resolution data (OLI/Landsat, WFV/GaoFen-1), with a mean relative difference of 9.6%. Furthermore, an analysis of 17 same-day MODIS/Terra and MODIS/Aqua image pairs shows that large viewing angles, atmospheric turbidity, and sunglint can lead to an underestimation of Ulva coverage of up to 45% under extreme conditions.

The state-of-the-art OpenFOAM technology is used to develop a numerical model that can be devoted to numerically investigating wake-collapse internal waves generated by a submerged moving body. The model incorporates body geometry, propeller forcing, and stratification magnitude of seawater. The generation mechanism and wave properties are discussed based on model results. It was found that the generation of the wave and its properties depend greatly on the body speed. Only when that speed exceeds some critical value, between 1.5 and 4.5 m/s, can the moving body generate wake-collapse internal waves, and with increases of this speed, the time of generation advances and wave amplitude increases. The generated wake-collapse internal waves are confirmed to have characteristics of the second baroclinic mode. As the body speed increases, wave amplitude and length increase and its waveform tends to take on a regular sinusoidal shape. For three linearly temperature-stratified profiles examined, the weaker the stratification, the stronger the wake-collapse internal wave.

Caulis spatholobi and caulis sargentodoxae are two different kinds of traditional Chinese medicine, which are similar to each other in appearance, but they are from differ sources with different functions.. This paper presents their spectrum using terahertz time-domain spectroscopy technology combines spectral matching algorithm to identify five different kinds of these samples. Due to the complex chemical composition of traditional Chinese medicine, different components of the characteristic absorption peak occurred easily mutually overlapping, therefore, it’s very difficult to find obvious characteristic absorption peak in terahertz range, caulis spatholobi and caulis like this. Every sample was measured 10 times in some position. These standard spectral data have been calculated in different frequency, data show good stability in range of 0.2~1.3 THz. The second order differential method is used to process the THz spectrum data from 0.2~1.3 THz. These tiny differences of absorption coefficient have been hemerged between caulis sargentodoxae and caulis spatholobi and compare with these data using the method of correlation coefficient block coding method, spectral angle method and information divergence method, respectively. The analysis results, the spectral angle method is the best algorithm, the discriminate accuracy of a total of 100 sets of data is 95%. It is a new way to distinguish difference of traditional Chinese medicine.

To acquire high-quality operational data products for Chinese in-orbit and scheduled ocean color sensors, the performances of two operational atmospheric correction (AC) algorithms (ESA MEGS 7.4.1 and NASA SeaDAS 6.1) were evaluated over the East China Seas (ECS) using MERIS data. The spectral remote sensing reflectance R rs(λ), aerosol optical thickness (AOT), and Angstrom exponent (α) retrieved using the two algorithms were validated using in situ measurements obtained between May 2002 and October 2009. Match-ups of R rs, AOT, and α between the in situ and MERIS data were obtained through strict exclusion criteria. Statistical analysis of R rs(λ) showed a mean percentage difference (MPD) of 9%–13% in the 490–560 nm spectral range, and significant overestimation was observed at 413 nm (MPD>72%). The AOTs were overestimated (MPD>32%), and although the ESA algorithm outperformed the NASA algorithm in the blue-green bands, the situation was reversed in the red-near-infrared bands. The value of α was obviously underestimated by the ESA algorithm (MPD=41%) but not by the NASA algorithm (MPD=35%). To clarify why the NASA algorithm performed better in the retrieval of α, scatter plots of the α single scattering albedo (SSA) density were prepared. These α-SSA density scatter plots showed that the applicability of the aerosol models used by the NASA algorithm over the ECS is better than that used by the ESA algorithm, although neither aerosol model is suitable for the ECS region. The results of this study provide a reference to both data users and data agencies regarding the use of operational data products and the investigation into the improvement of current AC schemes over the ECS.

Properly interpreting lidar (light detection and ranging) signal for characterizing particle distribution relies on a key parameter, χ p ( π ) , which relates the particulate volume scattering function (VSF) at 180° ( β p ( π ) ) that a lidar measures to the particulate backscattering coefficient ( b bp ). However, χ p ( π ) has been seldom studied due to challenges in accurately measuring β p ( π ) and b bp concurrently in the field. In this study, χ p ( π ) , as well as its spectral dependence, was re-examined using the VSFs measured in situ at high angular resolution in a wide range of waters. β p ( π ) , while not measured directly, was inferred using a physically sound, well-validated VSF-inversion method. The effects of particle shape and internal structure on the inversion were tested using three inversion kernels consisting of phase functions computed for particles that are assumed as homogenous sphere, homogenous asymmetric hexahedra, or coated sphere. The reconstructed VSFs using any of the three kernels agreed well with the measured VSFs with a mean percentage difference < 5 % at scattering angles < 170 ∘ . At angles immediately near or equal to 180°, the reconstructed β p ( π ) depends strongly on the inversion kernel. χ p ( π ) derived with the sphere kernels was smaller than those derived with the hexahedra kernel but consistent with χ p ( π ) estimated directly from high-spectral-resolution lidar and in situ backscattering sensor. The possible explanation was that the sphere kernels are able to capture the backscattering enhancement feature near 180° that has been observed for marine particles. χ p ( π ) derived using the coated sphere kernel was generally lower than those derived with the homogenous sphere kernel. Our result suggests that χ p ( π ) is sensitive to the shape and internal structure of particles and significant error could be induced if a fixed value of χ p ( π ) is to be used to interpret lidar signal collected in different waters. On the other hand, χ p ( π ) showed little spectral dependence.

The SMOS (soil moisture and ocean salinity) mission undertaken by the European Space Agency (ESA) has provided sea surface salinity (SSS) measurements at global scale since 2009. Validation of SSS values retrieved from SMOS data has been done globally and regionally. However, the accuracy of SSS measurements by SMOS in the China seas has not been examined in detail. In this study, we compared retrieved SSS values from SMOS data with in situ measurements from a South China Sea (SCS) expedition during autumn 2011. The comparison shows that the retrieved SSS values using ascending pass data have much better agreement with in situ measurements than the result derived from descending pass data. Accuracy in terms of bias and root mean square error (RMS) of the SSS retrieved using three different sea surface roughness models is very consistent, regardless of ascending or descending orbits. When ascending and descending measurements are combined for comparison, the retrieved SSS using a semi-empirical model shows the best agreement with in situ measurements, with bias -0.33 practical salinity units and RMS 0.74. We also investigated the impact of environmental conditions of sea surface wind and sea surface temperature on accuracy of the retrieved SSS. The SCS is a semi-closed basin where radio frequencies transmitted from the mainland strongly interfere with SMOS measurements. Therefore, accuracy of retrieved SSS shows a relationship with distance between the validation sites and land.

The semi-closed Rushan Bay is one of the largest aquaculture bases in North China, with its only navigation channel connecting the Rushan harbour and the Yellow Sea. Recent economic growth with increased import and export demands have stimulated a dredging operation, starting on 26 March 2010, which was paused on 17 June 2010 after numerous reports of mortality of cultured shellfish, such as clam (Ruditapes philippinarum), among other precious marine animals. A lawsuit was filed to settle the dispute between the dredging company and an aquaculture company, yet there was endless debate on whether the mortality was caused by the dredging operations. Here, using multi-sensor remote-sensing data collected by Landsat/ETM+, HJ-1A&1 B/CCD, and Aqua & Terra/MODIS, we addressed the two critical questions of (1) whether there was a significant increase in the suspended particulate matter (SPM) in the aquaculture area during and after the dredging operations; and (2) if the answer is yes, whether such an increase wa...

Optical models for the retrieval of shallow water bottom depth and albedo using multispectral data usually require in situ water depth data to tune the model parameters. In the South China Sea (SCS), however, such in situ data are often lacking or obsolete (perhaps from half a century ago) for most coastal waters around its islands and reefs. Here, we combine multispectral data collected by MODIS and Landsat to estimate bottom depth and albedo for four coral reef regions in the SCS, with results partially validated by some scarce in situ data. The waters in these remote regions are oligotrophic whose optical properties can be well derived from Moderate Resolution Imaging Spectroradiometer (MODIS) measurements when the waters are optically deep. The MODIS-derived optical properties are used to estimate the water column attenuation to the Landsat measurements over shallow waters, thus eliminating the requirement of model tuning using field measured water depths. The model is applied to four Landsat Thematic...

An optical closure study on bio-optical relationships was carried out using radiative transfer model matrix operator method developed by Freie Universitat Berlin. As a case study, the optical closure of bio-optical relationships empirically parameterized with in situ data for the East China Sea was examined. Remote-sensing reflectance (Rrs) was computed from the inherent optical properties predicted by these biooptical relationships and compared with published in situ data. It was found that the simulated Rrs was overestimated for turbid water. To achieve optical closure, bio-optical relationships for absorption and scattering coefficients for suspended particulate matter were adjusted. Furthermore, the results show that the Fournier and Forand phase functions obtained from the adjusted relationships perform better than the Petzold phase function. Therefore, before bio-optical relationships are used for a local sea area, the optical closure should be examined.

The recently commercialized LISST-VSF instrument measures the volume scattering function (VSF) from 0.1° to 15° with a traditional laser diffraction unit (LISST) and from 15° to 155° with an eyeball component. Between these two optical components, only the LISST unit is calibrated. The eyeball measurements are scaled using the VSFs at 15° that are measured by both components. As this relative calibration relies on a valid measurement at 15° by the LISST, it might fail in clear oceanic waters, where the forward scattering is relative weak either due to a lack of large particles or an overall low concentration of all particles. In this study, we calibrated the LISST-VSF eyeball component through a series of lab experiments using standard polystyrene beads. Validation with the beads of two different sizes showed a median difference of 11.1% between theoretical and calibrated values. Further evaluations with in situ data collected by the LISST-VSF and an ECO-BB3 meter indicated that the new calibration worked well in both turbid and clear waters, while the relative calibration method tended to overestimate VSFs in clear waters.

Results of microwave radar Doppler spectra from 1-D nonlinear ocean surface at moderate- and low-grazing angles are calculated by the composite surface scattering model. For the large-scale undulating surface description, the narrow-band Lagrange model is used, which takes into account the vertical and horizontal skewnesses. Moreover, the shadow and the curvature effects of large-scale waves on the Doppler spectra are also considered in our calculations. Comparisons of computed curves with experimentally measured Doppler spectra at different incidence angles and at various wind speeds show that the simulated results can fit the measured data well at moderate incident angles. From the simulations, we also find that the hydrodynamic modulation and the horizontal skewness of the large-scale waves can induce remarkable influence on Doppler shift. In addition, when the shadow and the curvature effects of large-scale waves are considered in the calculations, the Doppler shifts grow more quickly and the spectral widths become narrower at low-grazing angles, and this is consistent with the numerical results given by Toporkov in the nonlinear surface case. The conclusions obtained in this work seem promising for better understanding the properties of time-dependent radar echoes from oceanic surfaces.

Ocean oil spills cause serious damage to the marine environment, especially around coastal waters. Synthetic aperture radar (SAR) has been proven to be a useful tool for oil spill detection under low to moderate wind conditions. SAR operates in the microwave band and the data is not affected by the cloud cover and day/night conditions. However, the operational application of SAR for oil spill detection in the ocean is limited by false alarm targets or lookalike phenomena such as low wind speed, natural films, etc. In this study, we develop analysis of variance (ANOVA) to extract the features based on their characteristic geometry, grey level and texture features in the SAR images. We further analysed a fuzzy logic algorithm to separate oil spills features from lookalikes. We trained this algorithm using 38 SAR images (11 ENVISAT-Advanced Synthetic Aperture Radar (ASAR) and 27 European Remote Sensing (ERS)-2 SAR images) with 120 known oil spills and 80 lookalikes to generate an oil spill probability of a dark pixel in a SAR image. An independent set of 26 SAR images were used to validate the algorithm and it was found that 80.9% of the oil spills were correctly classified, and 20.0% of the lookalikes were wrongly classified as oil spills. The complete algorithmic procedure was coded in Matlab7.0 using its Fuzzy Logic Toolbox.

The design of vision measurement system of double optical paths with single CCD based on the digital signal processor (DSP) is presented. Using TMS320F2812 as the intelligent control unit, the CCD driving circuit, level conversion circuit and CCD output signal data acquisition and processing circuit are designed. By means of plane reflectors, the optical structure of the system is optimized, which reduces errors owing to tilt effect of the measured unit, improves measuring accuracy and makes the system more compact. Double optical paths signal data acquisition with single CCD is demonstrated. In addition, the improved resolution is enhanced up to sub-pixel level by the average polynomial interpolation algorithm.

Wave-number spectrum technique is proposed to retrieve coastal water depths by means of Synthetic Aperture Radar (SAR) image of waves. Based on the general dispersion relation of ocean waves, the wavelength changes of a surface wave over varying water depths can be derived from SAR. Approaching the analysis of SAR images of waves and using the general dispersion relation of ocean waves, this indirect technique of remote sensing bathymetry has been applied to a coastal region of Xiapu in Fujian Province, China. Results show that this technique is suitable for the coastal waters especially for the near-shore regions with variable water depths.

In the present paper new algorithms to derive sea state developed at the German Aerospace Center are briefly introduced and used to determine SAR derived spectral sea state and individual parameters. As an example of SAR measurements for a severe North Pacific storm, which produced significant wave height (SWH) above 10 m are compared to ECMWF model results and Radar Altimeter. The results are intercompared and validated. Further an example of a cross sea is analyzed. It occurred in the South East Pacific and was captured clearly by consecutive ERS-2 SAR wave mode images acquired on August 10, 2000. The WAM model spectra, SAR cross spectra and nonlinear SAR retrieved spectra together with derived integral parameters of the spectra are used to analyze the generation and development of the cross sea. The swell dissipation is observed to increase in the cross sea.

Oil spills are one of the major environmental concerns, especially in the coastal zones of the ocean. Synthetic aperture radar (SAR) imagery from the European Remote Sensing (ERS)-2 and Envisat satellites has proved to be a useful tool for monitoring oil spills in the marine environment due to its all-weather and all-time capability. More than 600 scenes with SAR images acquired over the western part of the East China Sea in 2002-2005 were collected, and of these, 120 scenes containing pronounced oil spills were processed and analysed. To analyse SAR image signatures of the oil spills, a geographic information system (GIS) framework was used. The oil spills were distinguished from look-alike phenomena by using other remote sensing data, and contextual information was incorporated into the GIS to obtain an oil spill distribution map for the western part of the East China Seas. Analysis of the temporal and spatial distribution of the oil spills revealed the risk areas and confirmed previous findings that oil spills are mainly distributed along regional shipping routes. This verifies that illegal discharges from ships are the main source of oil pollution in this region. The detailed analysis also revealed different types of oil pollution and showed diurnal and seasonal variations in the amount of oil spills detected by SAR images acquired in the morning/evening time and in the summer/winter.

Previous studies of the Mediterranean Sea outflow and meddies (O&M) were limited by the poor spatial and temporal resolution of conventional in situ observations as well as the confinement of satellite observations to the ocean’s surface. Accordingly, little is known about the formation and transport of meddies and the spatial and temporal variation of O&M trajectories, which are located, on average, at a depth of 1000 m. However, a new remote sensing method has been developed by the authors to observe and study the O&M through unique approaches in satellite multisensor data integration analyses. Satellite altimeter, scatterometer, infrared satellite imagery, and XBT data were used to detect and calculate the trajectories and the relative transport of the O&M (January 1993–December 2002). Two experiments [covering 1993–95: A Mediterranean Undercurrent Seeding Experiment (AMUSE) and Structures des Echanges Mer–Atmosphère, Propriétés des Hétérogénéités Océaniques: Recherche Expérimentale (SEMAPHORE)] and XBT temperature measurements were used to directly validate the method presented herein. The monthly mean features derived from floats and XBTs for multiple meddies and the results of the presented method were significantly correlated based on a statistical chi-square test. In addition, the complex singular value decomposition method was used to identify the propagating features and their phase speeds. It was found that saltier water from the Mediterranean Sea was transported into the North Atlantic Ocean over the Strait of Gibraltar in boreal spring and summer relative to boreal autumn and winter. Streamfunctions using altimetry, and time–frequency energy distributions using the Hilbert–Huang transform, were computed to evaluate the meddy interactions with the sea surface variation. Since the O&M play a significant role in carrying salty water from the Mediterranean Sea into the Atlantic, such new knowledge about their trajectories, transport, and life histories is important to the understanding of their mixing and interaction with North Atlantic water. This may lead to a better understanding of the global ocean circulation and global climate change.

Satellite multi-sensor data is used to derive sensible heat flux (SHF), Bowen ratio (Bo), and thus latent heat flux (LHF) in the tropical Pacific. The temperature differences at the air–sea interface are determined empirically for regions where strong deep air convection is present due to the buoyancy force. The vertical airflow results in surface wind divergence, which is estimated from scatterometer wind vector fields. The areas of positive temperature differences between sea surface temperature and atmospheric temperature estimated using surface wind divergence and in situ measurements are highly consistent in the tropical Pacific, especially in two convergence zones, i.e., the Intertropical Convergence Zone (ITCZ), and the South Pacific Convergence Zone (SPCZ). The bulk formulated SHF, determined by surface wind divergence (SHFBWD), is compared with a long-term time series (January 1993–December 1999) of the SHF from the National Centers for Environmental Prediction (NCEP) reanalyzed model data (SHFM). In the ITCZ, the correlation coefficients and the Root Mean Square (RMS) differences between SHFBWD and SHFM are over 70% and in the order of less than 4 W/m2, respectively. Furthermore, the bulk formulated latent heat flux (LHFB) is obtained using the empirical Bowen ratio (BoE) and SHFBWD. The BoE for the tropical Pacific was estimated using only sea surface temperature, which is valid when the vapor is saturated near sea surface. The RMS differences between SHFBWD and LHFB are estimated as 3.5 and 39.3 W/m2, respectively. In addition, the differences of SHFBWD and LHFB during the boreal winters are smaller than that in the boreal summers. Finally, in order to study spatial and temporal variations, we apply Empirical Orthogonal Function (EOF) analysis to SHFBWD and LHFB and compare with EOF analysis of Coupled Ocean and Atmosphere Data Set (COADS)'s SHF and LHF.

We analyze the refraction of long oceanic waves at the Gulf Stream's north wall off the Florida coast as observed in imagery obtained from the RADARSAT-1 synthetic aperture radar (SAR) during the passage of Hurricane Bonnie on August 25, 1998. The wave spectra are derived from RADARSAT-1 SAR images from both inside and outside the Gulf Stream. From the image spectra, we can determine both the long wave's dominant wavelength and its propagation direction with 180/spl deg/ ambiguity. We find that the wavelength of hurricane-generated ocean waves can exceed 200 m. The calculated dominant wavelength from the SAR image spectra agree very well with in situ measurements made by National Oceanic and Atmospheric Administration National Data Buoy Center buoys. Since the waves mainly propagate toward the continental shelf from the open ocean, we can eliminate the wave propagation ambiguity. We also discuss the velocity-bunching mechanism. We find that in this very long wave case, the RADARSAT-1 SAR wave spectra should not be appreciably affected by the azimuth falloff, and we find that the ocean swell measurements can be considered reliable. We observe that the oceanic long waves change their propagation directions as they leave the Gulf Stream current. A wave-current interaction model is used to simulate the wave refraction at the Gulf Stream boundary. In addition, the wave shoaling effect is discussed. We find that wave refraction is the dominant mechanism at the Gulf Stream boundary for these very long ocean swells, while wave reflection is not a dominant factor. We extract 256-by-256 pixel full-resolution subimages from the SAR image on both sides of the Gulf Stream boundary, and then derive the wave spectra. The SAR-observed swell refraction angles at the Gulf Stream north wall agree reasonably well with those calculated by the wave-current interaction model.

An adaptive threshold segmentation algorithm to extract dark targets from SAR images is presented, which is the key procedure to establish an automatic oil spill detection system. The extracted dark targets will then be sent to a classifier, such as a neural network, to discriminate oil spills and look-alikes. In order to reduce the calculation amount of following classifier, some simple filters are applied to reduce the look-alikes as many as possible while ensuring all oil spills are remained. Accurate local background estimation is required to determine the dark targets. Usually, the mean brightness of a small sliding window is used to estimate the background brightness. But it is not suitable for big dark targets. To avoid the effect of big dark targets, the proposed algorithm firstly estimates a rough background and then iteratively refines the background estimation. In each step, the rough dark targets are extracted based on the rough background. The new background is then calculated by removing the dark targets. The procedures above repeat iteratively and finally the best estimated background and dark targets are obtained simultaneously. The first guess background can be calculated by fitting the azimuthal averaged brightness trend along the range with parabolic curve.

Our recent study shows that Hyperion data and Hyperspectral Optimization Process Exemplar (HOPE) can effectively retrieve the shallow water depth in the South China Sea. In this study, the HJ-1A/HSI and EO-1/Hyperion remote sensing reflectance (R rs ) is simulated by the ocean radiative transfer software Hydrolight and used to derive shallow water depth with HOPE. Data merging is simulated in four different types of sea water inherent optical properties and four different bottom types. The results show Lee's weight mean theory performs obviously better than arithmetic mean, geometric mean in different conditions, which relates to bottom reflectance and seawater inherent optical properties. We further find that the difference between arithmetic mean, geometric mean and weighted mean decrease with the increase of water depth in the range of 0 to 20m and which depends on the bottom reflectance and seawater inherent optical properties. It will contribute to data merging of shallow water depth derived from hyperspectral data.

The general process of oil spill detection from SAR image with artificial neural network (ANN) classifier briefly includes five steps, target extraction, feature extraction, feature selection, ANN training and ANN classification. Feature extraction and feature selection are concerned in this paper. Firstly, 68 features are calculated for each target. By cross-correlation analysis, 24 features are selected to build a neural network to classify oil spills and look-alikes. The impact of imbalance sample data set on the performance of classification is also considered. In the end, principal component analysis (PCA) is applied on 24 features to reduce the dimension of feature space. The best number of principal components is found out.

A radiative transfer model was applied to examine the effects of vertically stratified inherent optical properties of the water column associated with near-surface plumes of suspended particulate matter on spectral remote-sensing reflectance, R(rs)(λ), of coastal marine environments. The simulations for nonuniform ocean consisting of two layers with different concentrations of suspended particulate matter (SPM) are compared with simulations for a reference homogeneous ocean whose SPM is identical to the surface SPM of the two-layer cases. The near-surface plumes of particles are shown to exert significant influence on R(rs)(λ). The sensitivity of R(rs)(λ) to vertical profile of SPM is dependent on the optical beam attenuation coefficient within the top layer, c(1)(λ), thickness of the top layer, z(1), and the ratio of SPM in the underlying layer to that in the top layer, SPM(2)/SPM(1), as well as the wavelength of light, λ. We defined a dimensionless spectral parameter, P(λ)=c(1)(λ)×z(1)×(SPM(2)/SPM(1)), to quantify and examine the effects of these characteristics of the two-layer profile of SPM on the magnitude and spectral shape of R(rs)(λ). In general, the difference of R(rs)(λ) between the two-layer and uniform ocean decreases to zero with an increase in P(λ). For the interpretation of ocean color measurements of water column influenced by near-surface plumes of particles, another dimensionless parameter P'(λ) was introduced, which is a product of terms representing homogenous ocean and a change caused by the two-layer structure of SPM. Based on the analysis of this parameter, we found that for the two-layer ocean there is a good relationship between R(rs)(λ) in the red and near-infrared spectral regions and the parameters describing the SPM(z) profile, i.e., SPM(1), SPM(2), and z(1).

Terahertz time-domain spectroscopy (THz-TDS) is an important part of THz technology, but its low scan speed always becomes the bottleneck In this article signals of TDS system under different scan speed were compared. The signal quality was getting worse while scan speed was increasing, and the time constant of lock-in amplifier plays an important role in the process. The main noise was found introduced from the circuit according to the experiment results.

International audience; So far, sea surface scattering polarization sensitivity is still difficult to fully understand. To gain understanding, full polarization C-band data spectral analysis is considered and the de-polarization (HV) and polarization ratio (PR) are jointly analysed with in-situ wind and wave observations.

International audience; A simulation of the radar backscatter from the complex sea surface has been established based on the eigenvector invariant property under rotations about the line of sight. The complex sea surface may have stationary or anchoring man-made targets as well as may be contaminated by surface covering layers such as oil spill. To better understand the scattering mechanism on the radar imagery from sea surface, we view the latter as a surface abnormal modulation (Mab) using a physical scattering method based on the target decomposition (TD) theorem.

International audience; In the present paper, Equivalent Number of Looks (ENL) are estimated for quad polarization RADARSAT-2 SLC data, and used to define a detection method. The method is using a threshold two-tuple, combining a polarimetric ENL estimator with CFAR to reveal ship region of interesting (ROI). The ROIs are then further investigated by polarization synthesis. An optimal VV/HH ratio was calculated for both ship and speckle, and a Polarization Orientation Angle (PAO) based analysis for microwave backscatter ship ROIs has further been carried out.

[1] A massive bloom of the green macroalgae Ulva prolifera (previously known as Enteromorpha prolifera) occurred in June 2008 in the Yellow Sea (YS), resulting in perhaps the largest “green tide” event in history. Using a novel index (Floating Algae Index) and multiresolution remote sensing data from MODIS and Landsat, we show that U. prolifera patches appeared nearly every year between April and July 2000–2009 in the YS and/or East China Sea (ECS), which all originated from the nearshore Subei Bank. A finite volume numerical circulation model, driven by realistic forcing and boundary conditions, confirmed this finding. Analysis of meteorological/environmental data and information related to local aquaculture activities strongly supports the hypothesis that the recurrent U. prolifera in the YS and ECS resulted from aquaculture of the seaweed Porphyra yezoensis (or nori) conducted along the 200 km shoreline of the Subei Bank north of the Changjiang (Yangtze) River mouth. Given the continuous growth in aquaculture efforts in the region, similar macroalgae bloom events, such as the summer 2008 event, are likely to occur in the future, particularly between May and July. This was confirmed by the 2009 bloom event in the same regions and the same period. The profit of the local P. yezoensis aquaculture industry (∼16,000 Ha in 2007) is estimated as U.S. $53 million, yet the cost to manage the impact of the summer 2008 U. prolifera bloom exceeded U.S. $100 million. Therefore, better strategies are required to balance the economic benefit of seaweed aquaculture and the costs of environmental impacts.

The theory and experiments for a multichannel optical system for pseudocolor encoding of images are presented. Spatial-frequency pseudocolor encoding is accomplished by spatial filtering different-colored spectra in different channels. Density pseudocolor encoding is accomplished by the incoherent addition of three primary color images: a contrast-reversal image in one color, a positive image in the second color, and a contrast half-reversal image in the third color. This is a simple, real-time technique. It has no resolution loss that is due to the use of gratings or halftone screens, and the optical system does not require Fourier-transform lenses with large relative apertures.

A theoretical model was developed estimating the scattering by seawater that are due to concentration fluctuation. Combining with the model proposed for density fluctuation (Optics Express, 17, 1671, 2009), we evaluated the overall effect of sea salts on the scattering. The variation of seawater scattering with the salinity is a combination of two factors: decreasing contribution due to density fluctuation and increasing contribution due to concentration fluctuation, with the latter effect dominating. The trend is, however, slightly non-linear and the linear adjustment of scattering with salinity that is frequently used would lead to an underestimate by an average of 2%. The results estimated at S = 38.4 per thousand agree with the measurements by Morel (Cahiers Oceanographiques, 20, 157, 1968) with an average difference of 1%, well within his experimental error of 2%. The spectral signature also varies with salinity, with the power-law slope increasing from -4.286 to -4.306 for salinity from 0 to 40 per thousand.

This paper discusses the relationship between the observations of submarine sand wave SAR images in Taiwan shoal and sea surface wind. A total of 43 SAR images over 11 years are collected and 496 profiles of sand wave SAR images are used, the wind are estimated from blended wind data and current direction is from mode. Results show submarine sand waves are observed by SAR under wind speed of 10 m/s, only littlie are imaged above 10 m/s. The number of observed sand waves reaches its maximum under the adverse wind direction, while the crosswind has its minimum. These support that low and middle wind speed and adverse wind direction are favorable for SAR imaging submarine sand waves, high wind speed and crosswind are unfavorable. The comparison between monthly mean wind speed and sand waves observed by SAR also shows a strong correlation between both, which is lower wind speeds, the higher probability of sand waves observed by SAR. This may indicate that the higher observation of the sand waves by SAR is partly due to wind speed.

The East China Sea is a typical case 2 water environment, where concentrations of phytoplankton pigments, suspended matter, and chromophoric dissolved organic matter (CDOM) are all higher than those in the open oceans, because of the discharge from the Yangtze River and the Yellow River. By using a hyperspectral semianalytical model, we simulated a set of remote-sensing reflectance for a variety of chlorophyll, suspended matter, and CDOM concentrations. From this simulated data set, a new algorithm for the retrieval of chlorophyll concentration from remote-sensing reflectance is proposed. For this method, we took into account the 682-nm spectral channel in addition to the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) channels. When this algorithm was applied to a field data set, the chlorophyll concentrations retrieved through the new algorithm were consistent with field measurements to within a small error of 18%, in contrast with that of 147% between the SeaWiFS ocean chlorophyll 2 algorithm and the in situ observation.

Based on the analytical expression derived from the high frequency ocean spectrum balance equation but not surface wave action balance equation, continuity equation and the first order Bragg backscattering theory, a simulating model for the shallow water bathymetry SAR relative normalized radar backscattering cross-section has been developed. The relationship between SAR relative normalized radar backscattering cross-section and currents, winds, wave length, incidence angle and the polarization has been simulated and the optimal conditions for shallow water bathymetry by SAR was also analyzed, the conclusion was given in the last section. Valuable help for the study on SAR shallow water bathymetry surveys will be provided from this paper.

Analytical expression of normalized radar backscattering cross-section (NRCS) contrasts for shallow water bathymetry SAR images has been firstly obtained by applying the continuity equation and the first order Bragg backscattering theory, and replacing the surface wave action balance equation with high frequency ocean wave spectrum balance equation. Based on the expression, we have simulated C band NRCS contrasts under different currents and sea surface winds firstly, results show the trend of NRCS contrasts' change with the shallow water bathymetry, and preferable currents and sea surface winds conditions for mapping shallow water bathymetry by SAR, which agree well with observations and shallow water bathymetry SAR images simulations. Moreover, the NRCS contrasts index which means the relationship between each currents and sea surface winds under given bathymetry parameters is first quantitatively calculated, which gives scientific proof for carrying SAR shallow water bathymetry surveys according to the ocean and weather conditions.

Oil spills in the ocean are one of major environmental concerns, especially in the coastal waters. Multispectral satellite sensors, such as AVHRR, MODIS and MERIS, have been used to detect oil spills which often exhibit a differing spectral reflectance than the surrounding waters. Some simple image processing methods, such as contrast enhancement, have been applied to remote sensing images to delineate the oil spills. But these methods often require subjective judgment from an operator and can not be used in an automatic manner, which is desirable when there is no a priori knowledge of occurrence or the spectral attributes of spills. In this study, we used a fuzzy C-means (FCM) cluster algorithm with a texture feature analysis to detect oil spill using MODIS images. The MODIS images of one incident, which happened near the new port of Dalian in Northeast China's Liaoning Province on April 3, 2005, were analyzed and the results proved the efficiency of algorithm. However, in very near shore regions, delineation of water and oil boundary is noisy due to a similar spectral signature across land-water boundary.