This PDF file contains the front matter associated with SPIE Proceedings Volume 9999 including the Title Page, Copyright information, Table of Contents, Introduction, and Conference Committee listing.

It is well known that Internal Waves of tidal frequency (i.e. Internal Tides) are successfully detected in seasurface height (SSH) by satellite altimetry [1]. Shorter period Internal Solitary Waves (ISWs), whose periods are an order of magnitude smaller than tidal internal waves, are however generally assumed too small to be detected with standard altimeters (at low sampling rates, i.e. 1 Hz). This is because the Radar Altimeter (RA) footprint is somewhat larger, or of similar size at best, than the ISWs typical wavelengths. Here it will be demonstrated that new generation high sampling rate satellite altimetry data (i.e. ~20 Hz) hold a variety of short-period signatures that are consistent with surface manifestations of ISWs in the ocean. Our observational method is based on satellite synergy with imaging sensors such as Synthetic Aperture Radar (SAR) and other high-resolution optical sensors (e.g. 250m resolution MODIS images) with which ISWs are unambiguously recognized. A first order commonly accepted ISW radar imaging mechanism is based on hydrodynamic modulation models [2] [3] in which the straining of surface waves due to ISW orbital currents is known to cause modulation of decimeter-scale surface waves, which have group velocities close to the IW phase velocity. This effect can be readily demonstrated by measurements of wind wave slope variances associated with short-period ISWs, as accomplished in the pioneer work of Hughes and Grant [4]. Mean square slope can be estimated from nadir looking RAs using a geometric optics (specular) scattering model [5][6][7], and directly obtained from normalized backscatter (sigma0) along-track records. We use differential scattering from the dual-band (Ku- and C-bands) microwave pulses of the Jason- 2 high-rate RA to isolate the contribution of small-scale surface waves to mean square slope. The differenced altimeter mean square slope estimate, derived for the nominal wave number range 40–100 rad/m, is then used to detect ISWs in records of along-track high sampling rate RAs. The RA signatures of these ISWs are also apparent in radar backscattered pulse waveforms from the original Sensor Geophysical Data Records (SGDR), in high resolution (20-Hz) data. The shape of these waveforms is modified by the ISWs with respect to waveforms unperturbed by short-period internal waves. Hence, a new method for identification of ISWs in high-rate RA records that combines along-track differenced mean square slopes across ISW crests and waveform shape variation is put forward in this paper. Validation of the method is warranted with quasi-coincident (in time and space) SAR images of ISWs in various deep ocean regions, such as the Andaman Sea, the Mascarene Ridge of the Indian Ocean and the North Atlantic tropical ocean. The practical significance of this new method is related to the anticipated SWOT wide-swath altimeter mission as well as the recently launched Sentinel-3A SARAL, for which removal of internal wave signals may be of critical importance for observing other high-frequency sub-mesoscale dynamics.

In this paper new results of laboratory studies of damping of gravity-capillary waves on the water surface covered by kerosene are presented and compared with our previous analysis of characteristics of crude oil and diesel fuel films. Investigations of kerosene films were carried out in a wide range values of film thicknesses (from some hundreds millimetres to a few millimetres) and in a wide range of surface wave frequencies (from 10 to 27 Hz). The selected frequency range corresponds to the operating wavelengths of microwave, Х- to Ka-band radars typically used for the ocean remote sensing. The studied range of film thickness covers typical thicknesses of routine spills in the ocean. It is obtained that characteristics of waves, measured in the presence of oil derivatives films differ from those for crude oil films, in particular, because the volume viscosity of oil derivatives and crude oil is strongly different. To retrieve parameters of kerosene films from the experimental data the surface wave damping was analyzed theoretically in the frame of a model of two-layer fluid. The films are assumed to be soluble, so the elasticity on the upper and lower boundaries is considered as a function of wave frequency. Physical parameters of oil derivative films were estimated when tuning the film parameters to fit theory and experiment. Comparison between wave damping due to crude oil, kerosene and diesel fuel films have shown some capabilities of distinguishing of oil films from remote sensing of short surface waves.

The feasibility of deriving bathymetry from data acquired with ATLAS, the photon-counting lidar on NASA’s upcoming ICESat-2 satellite, is assessed empirically by examining data from NASA’s airborne ICESat-2 simulator, MABEL. The primary objectives of ICESat-2 will be to measure ice-sheet elevations, sea-ice thickness, and global biomass. However, the 6-beam, green-wavelength photon-counting lidar, combined with the 91-day repeat period and near-polar orbit, may provide unique opportunities to measure coastal bathymetry in remote, poorly-mapped areas of the globe. The study focuses on high-probability bottom returns in Keweenaw Bay, Lake Superior, acquired during the “Transit to KPMD” MABEL mission in August, 2012 at an AGL altitude of 20,000 m. Water-surface and bottom returns were identified and manually classified using MABEL Viewer, an in-house prototype data-explorer web application. Water-surface returns were observed in 12 green channels, and bottom returns were observed in 10 channels. Comparing each channel’s mean water-surface elevation to a regional NOAA Nowcast water-level estimate revealed channel-specific elevation biases that were corrected for in our bathymetry estimation procedure. Additionally, a first-order refraction correction was applied to each bottom return. Agreement between the refraction-corrected depth profile and NOAA data acquired two years earlier by Fugro LADS with the LADS Mk II airborne system indicates that MABEL reliably detected bathymetry in depths up to 8 m, with an RMS difference of 0.7 m. In addition to feeding coastal bathymetry models, MABEL (and potentially ICESat-2 ATLAS) has the potential to seed algorithms for bathymetry retrieval from passive, multispectral satellite imagery by providing reference depths.

Investigation of the Doppler shift of radar return from the sea surface is very important for better understanding of capabilities of exploitation of microwave radar for measuring velocities of marine currents. Here new field experiments carried out from a Platform on the Black Sea with a coherent X-band scatterometer, and a Doppler multifrequency (X- /C-/S-band) dual-polarized radar recently designed at IAP RAS are discussed. It is shown that the radar return contains both Bragg (polarized) and non polarized scattering components, presumably giving different contributions to radar Doppler shifts. Radar Doppler shifts were estimated using two different definitions as a) a frequency of the “centre of gravity” of an instantaneous radar return spectrum (ASIS) averaged over periods of dominant wind waves and b) the “centre of gravity” of the averaged over dominant wave periods spectrum (SAS). The ASIS and SAS values for both VV and HH-polarizations are shown to be different due to effects of radar backscatter modulation by dominant (long) wind waves. The radar Modulation Transfer Function (MTF) has been analyzed from experimental data and difference between SAS- and ASIS-values has been satisfactory explained using the measured MTF-values. It is obtained that experimental values of ASIS can be satisfactory described by the Bragg model despite the significant contribution of NP component to the radar backscatter. A physical explanation of the effect is given.

A weighted multi-path model for the composite electromagnetic (EM) scattering and SAR image application of sea surface with a ship target is presented according to the distribution characteristics of specular reflection facets on a deterministic rough sea surface. This model reasonably includes the influence of non-negligible roughness of sea surface in the coupling scattering calculation, which could avoid the error caused by planar approximation in the traditional four-path model. Numerical simulation results show that the entire simulator could provide a preliminary prediction on the radar cross sections (RCS) for the composite scene with electrically large size. In addition, the total scattering contribution contains both the amplitude and phase information of the scattering facets on the composite ship-sea surface, which can be effectively applied in the scattering characteristics identification of ship target on the sea surface and SAR image simulation.

When Osborne and Burch [1] reported their observations of large-amplitude, long internal waves in the Andaman Sea that conform with theoretical results from the physics of nonlinear waves, a new research field on ocean waves was immediately set out. They described their findings in the frame of shallow-water solitary waves governed by the K-dV equation, which occur because of a balance between nonlinear cohesive and linear dispersive forces in a fluid. It was concluded that the internal waves in the Andaman Sea were solitons and that they evolved either from an initial waveform (over approximately constant water depth) or by a fission process (over variable water depth). Since then, there has been a great deal of progress in our understanding of Internal Solitary Waves (ISWs), or solitons in the ocean, particularly making use of satellite Synthetic Aperture Radar (SAR) systems. While two layer models such as those used by Osborne and Burch[1] allow for propagation of fundamental mode (i.e. mode-1) ISWs, continuous stratification permits the existence of higher mode internal waves. It happens that the Andaman Sea stratification is characterized by two (or more) maxima in the vertical profile of the buoyancy frequency N(z), i.e. a double pycnocline, hence prone to the existence of mode-2 (or higher) internal waves. In this paper we report solitary-like internal waves with mode-2 vertical structure co-existing with the large well know mode-1 solitons. The mode-2 waves are identified in satellite SAR images (e.g. TerraSAR-X, Envisat, etc.) because of their distinct surface signature. While the SAR image intensity of mode-1 waves is characterized by bright, enhanced backscatter preceding dark reduced backscatter along the nonlinear internal wave propagation direction (in agreement with Alpers, 1985[2]), for mode-2 solitary wave structures, the polarity of the SAR signature is reversed and thus a dark reduced backscatter crest precedes a bright, enhanced backscatter feature in the propagation direction of the wave. The polarity of these mode-2 signatures changes because the location of the surface convergent and divergent zones is reversed in relation to mode-1 ISWs. Mode-2 ISWs are identified in many locations of the Andaman Sea, but here we focus on ISWs along the Ten Degree Channel which occur along-side large mode-1 ISWs. We discuss possible generation locations and mechanisms for both mode-1 and mode-2 ISWs along this stretch of the Andaman Sea, recurring to modeling of the ray pathways of internal tidal energy propagation, and the P. G. Baines[3] barotropic body force, which drives the generation of internal tides near the shallow water areas between the Andaman and Nicobar Islands. We consider three possible explanations for mode-2 solitary wave generation in the Andaman Sea: (1) impingement of an internal tidal beam on the pycnocline, itself emanating from critical bathymetry; (2) nonlinear disintegration of internal tide modes; (3) the lee wave forming mechanism to the west of a ridge during westward tidal flow out of the Andaman Sea (as originally proposed by Osborne and Burch for mode-1 ISWs). SAR evidence is of critical importance for examining those generation mechanisms.

A study of new-ice formation, using Cosmo-SkyMed (CSK) SAR imagery, was planned for the period February - March, 2015 over Terra Nova Bay (Antarctica). The first survey of the images showed an unexpected surface feature, i.e., a prominent ice gyre which lasted from the image of 20 February to the one of 12 March; in the image of 17 March, the ice gyre appears already completely disrupted and a well-defined polynya comes into sight. The analysis of the gyre extent in the image sequence became the object of our study. The non-linear segmentation of the set of CSK images was performed by the perceptron algorithm; this is a significant challenge because of the random nature of the speckle degradation in SAR images. The final result is a set of binary patterns providing the gyre area of each image; by this it is possible to follow the time evolution of the particular feature.

Retrieving the water-leaving reflectance from airborne hyperspectral data implies to deal with three steps. Firstly, the radiance recorded by an airborne sensor comes from several sources: the real radiance of the object, the atmospheric scattering, sky and sun glint and the dark current of the sensor. Secondly, the dispersive element inside the sensor (usually a diffraction grating or a prism) could move during the flight, thus shifting the observed spectra on the wavelengths axis. Thirdly, to compute the reflectance, it is necessary to estimate, for each band, what value of irradiance corresponds to a 100% reflectance. We present here our calibration method, relying on the absorption features of the atmosphere and the near-infrared properties of common materials. By choosing proper flight height and flight lines angle, we can ignore atmospheric and sun glint contributions. Autocorrelation plots allow to identify and reduce the noise in our signals. Then, we compute a signal that represents the high frequencies of the spectrum, to localize the atmospheric absorption peaks (mainly the dioxygen peak around 760 nm). Matching these peaks removes the shift induced by the moving dispersive element. Finally, we use the signal collected over a Lambertian, unit-reflectance surface to estimate the ratio of the system's transmittances to its near-infrared transmittance. This transmittance is computed assuming an average 50% reflectance of the vegetation and nearly 0% for water in the near-infrared. Results show great correlation between the output spectra and ground measurements from a TriOS Ramses and the water-insight WISP-3.

This study has investigated the physical processes of energy exchange between the water surface and atmosphere over Lake Huron. The four components of surface energy balance, including net radiation, latent heat, sensible heat, and heat storage, were estimated using the eleven years (2002-2012) daily MODIS data together with in-situ measurements. Good agreement was found between the seasonal turbulent heat fluxes calculated from satellite data and those from the direct measurements (eddy covariance method) with correlation coefficients of 0.94 and 0.95 for sensible heat and latent heat, respectively. There were temporal, spatial heterogeneities, and strong seasonal pattern for all of the four components, which were very high in summer and low in winter for net radiation and heat storage. In contrast, latent heat and sensible heat were very high in the winter and very low in the summer. Trend analysis revealed long term changes for each of the energy balance components, particularly the increase in latent heat which was equivalent to evaporation rate of 0.017 mm m^-2 per year, indicating that lake evaporation increased by 0.19 mm m^-2 over the eleven years observation period. This was possibly a result of a smaller amount of over lake ice cover and an increase in surface water temperature of Lake Huron.

Infrared polarimetry is an emerging sensing modality that offers the potential for significantly enhanced contrast in situations where conventional thermal imaging falls short. Polarimetric imagery leverages the different polarization signatures that result from material differences, surface roughness quality, and geometry that are frequently different from those features that lead to thermal signatures. Imaging of the polarization in a scene can lead to enhanced understanding, particularly when materials in a scene are at thermal equilibrium. Polaris Sensor Technologies has measured the polarization signatures of oil on water in a number of different scenarios and has shown significant improvement in detection through the contrast improvement offered by polarimetry. The sensing improvement offers the promise of automated detection of oil spills and leaks for routine monitoring and accidents with the added benefit of being able to continue monitoring at night. In this paper, we describe the instrumentation, and the results of several measurement exercises in both controlled and uncontrolled conditions.

This study presents the results from a combined aerial survey performed with a hexacopter and a gyrocopter over a part of the Elbe estuary near Hamburg, Germany. The survey was conducted by the Federal Institute of Hydrology, Germany, and the Fraunhofer Application Center for Multimodal and Airborne Sensors as well as by a contracted engineering company with the aim to acquire spatial thermal infrared (TIR) data of the Hahnöfer Nebenelbe, a branch of the Elbe estuary. Additionally, RGB and NIR data was captured to facilitate the identification of water surfaces and intertidal mudflats. The temperature distribution of the Elbe estuary affects all biological processes and in consequence the oxygen content, which is a key parameter in water quality. The oxygen levels vary in space between the main fairway and side channels. So far, only point measurements are available for monitoring and calibration/validation of water quality models. To better represent this highly dynamic system with a high spatial and temporal variability, tidal streams, heating and cooling, diffusion and mixing processes, spatially distributed data from several points of time within the tidal cycle are necessary. The data acquisition took place during two tidal cycles over two subsequent days in the summer of 2015. While the piloted gyrocopter covered the whole Hahnöfer Nebenelbe seven times, the unmanned hexacopter covered a smaller section of the branch and tidal mudflats with a higher spatial and temporal resolution (16 coverages of the subarea). The gyrocopter data was acquired with a thermal imaging system and processed and georeferenced using the structure from motion algorithm with GPS information from the gyrocopter and optional ground control points. The hexacopter data was referenced based on ground control points and the GPS and position information of the acquisition system. Both datasets from the gyrocopter and the hexacopter are corrected for the effects of the atmosphere and emissivity of the water surface and compared to in situ measurements, taken during the data acquisition. Of particular interest is the effect of the observation angle on the brightness temperature acquired by the wide angle lenses on the platforms, which is up to 40° at the margins of the imagery. Here, both datasets show deviating temperatures, which are probably not due to actual temperature differences. We will discuss the position accuracy achieved over the water areas, the adaptation of atmospheric and emissivity correction to the observation angle and subsequent improvement of the temperature data. With two datasets of the same research area at different resolutions we will investigate the effects of the acquisition platforms, acquisition system and resolutions on the accuracy of the remotely sensed temperatures as well as their ability to represent temperature patterns of tidal currents and mixing processes.

We have examined the L-band radiometer and radar data from NASA’s Soil Moisture Active Passive (SMAP) mission for ocean research and applications. We find that the SMAP data are in excellent agreement with the geophysical model function (GMF) derived from the Aquarius data up to a wind speed of 20 ms^-1. For severe wind conditions, the higher resolution data from SMAP allowed us to assess the sensitivity of L-band radiometer signals to hurricane force winds. We applied the L-band GMF to the retrieval of ocean surface wind and SSS from the SMAP data. Comparison with the European Center for Medium-Range Weather Forecasting, WindSat and RapidSCAT wind speeds suggests that SMAP’s radiometer wind speed reaches an excellent accuracy of about 1.1-1.7 ms^-1 below a wind speed of 20 ms^-1. We have also found that the maximum wind speed derived from the SMAP radiometer data can reach 140 knots for severe storms and are generally in good agreement with the hurricane track analysis and operational aircraft Stepped Frequency Microwave Radiometer wind speeds. The spatial patterns of the SMAP SSS agree well with climatological distributions, but exhibit several unique spatial and temporal features.

We present the results of using Sentinel-2A Multispectral Imager Instrument (MSI/S2) and Landsat-8 Operational Land Imager (OLI/L8) data to monitor river plumes in the eastern Black Sea and from the Rhône River in the Mediterranean Sea. The focus is on exploring the possibility to investigate hydrodynamic processes associated with river outflows, in particular internal waves (IWs). Submesoscale IWs having wavelengths less than 50 m and generated by unstable sharp front of a river plume were revealed and their parameters were assessed. A map of surface manifestation of IW trains in the Gulf of Lions was created based on MSI/S2 images. There are different mechanisms of IW generation in river outflow zones, they are determined by a number of parameters including river discharge, bottom topography and presence of tidal currents or inertial period IWs in the shelf zone. A new phenomenon manifested as a chain of quasi circles was discovered. Inertial water motions were suggested as its prime cause, however, this hypothesis is yet to be investigated. An analysis of OLI/L8 and MSI/S2 data enabled us to consider in detail river debouchment streams. For the first time a wave pattern of such stream in the eastern Black Sea was observed in conditions of foehn winds. Usually, foehn winds are distinctly manifested in radar images. A joint analysis of quasi simultaneous ocean color MSI/S2 and Sentinel-1A SAR images demonstrated how water stream wave-like signatures differ from those of foehn winds.

Effective detection and tracking of Karenia brevis Harmful Algal Blooms (KB HAB) that frequently plague the coasts and beaches of the West Florida Shelf (WFS) is important because of their negative impacts on ecology. They pose threats to fisheries, human health, and directly affect tourism and local economies. Detection and tracking capabilities are needed for use with the Visible Infrared Imaging Radiometer Suite (VIIRS) satellite, so that HABs monitoring capabilities, which previously relied on imagery from the Moderate Resolution Imaging Spectroradiometer Aqua, can be extended to VIIRS. Unfortunately, VIIRS, unlike its predecessor MODIS-A, does not have a 678 nm channel to detect chlorophyll fluorescence, which is used in the normalized fluorescence height (nFLH) algorithm, or in the Red Band Difference (RBD) algorithm. Both these techniques have demonstrated that the remote sensing reflectance signal from the MODIS-A fluorescence band (Rrs 678 nm) helps in effectively detecting and tracking KB HABs in the WFS. To overcome the lack of a fluorescence channel on VIIRS, the approach described here, bypasses the need for measurements at 678nm, and permits extension of KB HABs satellite monitoring to VIIRS. The essence of the approach is the application of a standard multiband neural network (NN) inversion algorithm, previously developed and reported by us, that takes VIIRS Rrs measurements at the 486, 551 and 671nm bands as inputs, and produces as output the related Inherent Optical Properties (IOPs), namely: absorption coefficients of phytoplankton (aph443) dissolved organic matter (ag) and non-algal particulates (adm) as well as the particulate backscatter coefficient, (bbp) all at 443nm. We next need to relate aph443 in the VIIRS NN retrieved image to equivalent KB HABs concentrations. To do this, we apply additional constraints, defined by (i) low backscatter manifested as a maximum Rrs551 value and (ii) a minimum [Chla] threshold (and hence an equivalent minimum aph443min value) that are both known to be associated with KB HABs in the WFS. These two constraining filter processes are applied sequentially to the VIIRS NN retrieved aph443 image. First an image is made of retrieved VIIRS Rrs551. A mask is then made of all pixels with Rrs551≥ Rrs551max, the maximum value known to be compatible with the existence KB HABs. This is applied, as a filter to the VIIRS NN retrieved aph443 image to exclude pixels with Rrs551≥ Rrs551max. The residual image will then only show aph443 values that comply with Rrs551≤ Rrs551max. Then, in a second filter process, all values of aph443 ≤ aph443min are eliminated. The residual image will now only show aph443 values that are compatible with both criteria for KB HABs, and are therefore representative of KB HABs. It will be shown that when both these filter condition are applied to VIIRS NN aph443 retrievals, they can be used to effectively delineate and quantify KB HABs in the WFS. The KB HABs retrieved in this manner also show good correlations with in-situ KB HABs measurements as well as with nFLH retrievals and other techniques to which the same filtering criteria have been applied, confirming the viability of the approach.

Mapping of coral reefs provides information to support the conservation and monitoring of this vulnerable benthic habitat. Coral reef environment has a high level of complexity and spatial heterogeneity, however, typical maps derived using remote sensing data only includes classification of benthic communities. The study aims to update the status of coral reef classification through the advancement of remote sensing technology in the Philippines. This shows the coral community condition in the area. With the use of hyperspectral Compact Airborne Spectrographic Imager (CASI) and bathymetric LiDAR, data were acquired in Apo Reef, Province of Mindoro. Apo Reef is known as the second largest contiguous coral reef in the world. The image taken has a spatial resolution of 0.5 meters with spectral resolution of approximately 10nm between 385nm to 1047nm wavelength regions. Pre-processing of LiDAR data includes extraction of surface bottom and generating derivatives such as Digital Surface Model (DSM), Digital Terrain Model (DTM), rugosity, and slope. Data on spectral reflectance of coral reef types and other substrates, bathymetry, validation points and geotagged underwater video were gathered in situ simultaneous with the image acquisition. Derivative analysis is then applied to the field spectra to determine the wavelength bands for discriminating coral reef types. The optimal subset bands and LiDAR derivatives were used in classifying coral reef types using the supervised classification. Geotagged photos and sampling points were used to validate and assess the accuracy of the map.

With the successful launch of Landsat-8 in 2013 followed by a very recent launch of Sentinel-2A, we are entering a new area where frequent moderate resolution water quality products over coastal/inland waters will be available to scientists and operational agencies. Although designed for land observations, the Operational Land Imager (OLI) has proven to provide high-fidelity products in these aquatic systems where coarse-resolution ocean color imagers fail to provide valid observations. High-quality, multi-scale ocean color products can give insights into the biogeochemical/physical processes from the upstream in watersheds, into near-shore regions, and further out in ocean basins. In this research, we describe a robust cross-calibration approach, which facilitates seamless ocean color products at multi scales. The top-of-atmosphere (TOA) OLI imagery is cross-calibrated against near-simultaneous MODIS and VIIRS ocean color observations in high-latitude regions. This allows for not only examining the overall relative performance of OLI but also for characterizing non-uniformity (i.e., banding) across its swath. The uncertainty of this approach is, on average, found to be less than 0.5% in the blue channels. The adjustments made for OLI TOA reflectance products are then validated against in-situ measurements of remote sensing reflectance collected in research cruises or at the AERONET-OC.

Hyperspectral measurements of the water surface of urban coastal waters are presented. Oblique bidirectional reflectance factor imagery was acquired made in a turbid coastal sub estuary of the Indian River Lagoon, Florida and along coastal surf zone waters of the nearby Atlantic Ocean. Imagery was also collected using a pushbroom hyperspectral imager mounted on a fixed platform with a calibrated circular mechatronic rotation stage. Oblique imagery of the shoreline and subsurface features clearly shows subsurface bottom features and rip current features within the surf zone water column. In-situ hyperspectral optical signatures were acquired from a vessel as a function of depth to determine the attenuation spectrum in Palm Bay. A unique stationary platform methodology to acquire subsurface acoustic images showing the presence of moving bottom boundary nephelometric layers passing through the acoustic fan beam. The acoustic fan beam imagery indicated the presence of oscillatory subsurface waves in the urbanized coastal estuary. Hyperspectral imaging using the fixed platform techniques are being used to collect hyperspectral bidirectional reflectance factor (BRF) measurements from locations at buildings and bridges in order to provide new opportunities to advance our scientific understanding of aquatic environments in urbanized regions.

Retrieving the water-leaving reflectance from airborne hyperspectral data implies to deal with three steps. Firstly, the radiance recorded by an airborne sensor comes from several sources: the real radiance of the object, the atmospheric scattering, sky and sun glint and the dark current of the sensor. Secondly, the dispersive element inside the sensor (usually a diffraction grating or a prism) could move during the flight, thus shifting the observed spectra on the wavelengths axis. Thirdly, to compute the reflectance, it is necessary to estimate, for each band, what value of irradiance corresponds to a 100% reflectance. We present here our calibration method, relying on the absorption features of the atmosphere and the near-infrared properties of common materials. By choosing proper flight height and flight lines angle, we can ignore atmospheric and sun glint contributions. Autocorrelation plots allow to identify and reduce the noise in our signals. Then, we compute a signal that represents the high frequencies of the spectrum, to localize the atmospheric absorption peaks (mainly the dioxygen peak around 760 nm). Matching these peaks removes the shift induced by the moving dispersive element. Finally, we use the signal collected over a Lambertian, unit-reflectance surface to estimate the ratio of the system's transmittances to its near-infrared transmittance. This transmittance is computed assuming an average 50% reflectance of the vegetation and nearly 0% for water in the near-infrared. Results show great correlation between the output spectra and ground measurements from a TriOS Ramses and the water-insight WISP-3.

In-situ measurement of bottom reflectance signatures and bottom features in water are used to test an analytical based irradiance model protocol. Comparisons between predicted and measured bottom reflectance signatures are obtained using measured hyperspectral remote sensing reflectance signatures, water depth and water column constituent concentrations. Analytical solutions and algorithms are used to generate synthetic signatures of different bottom types. The analytical methodology used to simulated bottom reflectance contains offset and bias that can be corrected using spectral window based corrections. Example results are demonstrated for application to coral species, submerged aquatic vegetation and a sand bottom type. Spectral windows are identified for predicting the above bottom types. Sensitivity analysis of predicted bottom reflectance signatures is conducted by varying water depth, chlorophyll, dissolved organic matter and total suspended mater concentrations. The protocol can be applied to shallow subsurface geospatial mapping using sensor based water surface reflectance based upon an analytical model solution derived from primitive radiative transfer theory.

Until now, Indonesia only had a single large-scale bathymetry map (1:250.000) for the entire nation and detailed maps (1:50.000 or 1:25.000) of a few locations. A straightforward and cost-efficient bathymetry mapping of the Indonesian coral reef is urgently needed. To address this problem, we present a generalized multispectral bathymetry estimation formula that requires few field measurement data to adjust coefficients. The simulation dataset corresponding to the Indonesian coral reef and Worldview-2 Imagery spectral response was built to extract the coefficient. Then, the formula was validated using real Worldview- 2 images from three shallow coral reef sites: the Gili Mantra islands, Menjangan Island, and Gondol Beach in Indonesia. During the evaluation of the dataset simulation, the formulated equation was tested; it achieved an adjusted R² of 0.93 and an RMSR (Root Mean Square Residual) of 0.9 m. Such results show the good quality of our generalized bathymetry formula. Moreover, we tested the described formula using the imagery. The Gili islands shows that the best estimations of the depth corresponded to 0.62 and 1.5 m for R² and RMSR, respectively. In the shallow areas, the depth estimation was accurate, but the error gradually increased with depth. The depth estimation for the Menjangan and Gondol sites failed (R² ≤ 0.1), mostly because of a high image noise. In conclusion, the formula was able to estimate the depth accurately in a shallow water area using the least noisy image, but its error increased with depth.

The optical imagery has the potential for extraction of spatially and temporally explicit bathymetric information in inland/coastal waters. Lyzenga’s model and optimal band ratio analysis (OBRA) are main bathymetric models which both provide linear relations with water depths. The former model is sensitive and the latter is quite robust to substrate variability. The simple regression is the widely used approach for calibration of bathymetric models either Lyzenga’s model or OBRA model. In this research, a multiple regression is examined for empirical calibration of the models in order to take the advantage of all spectral channels of the imagery. This method is applied on both Lyzenga’s model and OBRA model for the bathymetry of a shallow Alpine river in Italy, using WorldView-2 (WV-2) and GeoEye images. Insitu depths are recorded using RTK GPS in two reaches. One-half of the data is used for calibration of models and the remaining half as independent check-points for accuracy assessment. In addition, radiative transfer model is used to simulate a set of spectra in a range of depths, substrate types, and water column properties. The simulated spectra are convolved to the sensors’ spectral bands for further bathymetric analysis. Investigating the simulated spectra, it is concluded that the multiple regression improves the robustness of the Lyzenga’s model with respect to the substrate variability. The improvements of multiple regression approach are much more pronounced for the Lyzenga’s model rather than the OBRA model. This is in line with findings from real imagery; for instance, the multiple regression applied for calibration of Lyzenga’s and OBRA models demonstrated, respectively, 22% and 9% higher determination coefficients (R²) as well as 3 cm and 1 cm better RMSEs compared to the simple regression using the WV-2 image.

Sea ice is an important factor for understanding Antarctic climate change. Especially, annual change of sea ice shows different trend in Antarctica and Arctic. This different variation need to continuously observe the Polar Regions. Sea Ice Albedo (SIA) and Sea Ice Concentration (SIC) are an indicator of variation on sea ice. In addition, albedo is key parameter to understand the energy budget in Antarctica. This being so, it is important to analyze long-term variation of the two factors for observing of change of Antarctic environment. In this study, we analyzed long-term variability of SIC and SIA to understand the changes of sea ice over Antarctic and researched the relationship with two factors. We used the SIA data at The Satellite Application Facility on Climate Monitoring (CM SAF) and the SIC data provided by Ocean and Sea Ice Satellite Application Facility (OSI-SAF) from 1982 to 2009. The study period was selected to Antarctic summer season due to polar nights. We divided study periods into two terms, Nov-Dec(ND) and Jan-Feb(JF) in order to reflect the characteristics of sea ice area, which minimum extend occurred in September and maximum extend occurred in February. We analyzed the correlation between SIA and SIC. As a results, two variables have a strong positive correlation (each correlation coefficients are 0.91 in Nov-Dec and 0.90 in Jan-Feb). We performed time series analysis using linear regression to understand the spatial and temporal tendency of SIA and SIC. As a results, SIA and SIC have a same spatial trend such as Weddle sea and Ross sea sections show the positive trend and Bellingshausen Amundsen sea shows the negative trend of two factors. Moreover, annual SIA change rate is 0.26% ~ 0.04% yr^-1 over section where represent positive trend during two study periods. And annual SIA change rate is - 0.14 ~ - 0.25 % yr^-1 of in the other part where represent negative trend during two study periods.

Numerous empirical algorithms have been operationally used to retrieve the global ocean chlorophyll-a concentration (Chla) from ocean color satellite data, e.g., the OC4V4 algorithm for SeaWiFS and OC3M for MODIS. However, the algorithms have been established and validated based on the in situ data mainly measured under low to moderate solar zenith angle (<70°). Currently, with the development of the geostationary satellite ocean color remote sensing which observes from early morning to later afternoon, it is necessary to know whether the empirical Chla algorithms could be applied to high solar zenith angle. In this study, the performances of seven widely-used Chla algorithms under high solar zenith angles, i.e., OC2, OC3M, OC3V, OC4V4, CLARK, OCI, and YOC algorithms, were evaluated using the NOMAD global in situ ocean color dataset. The results showed that the performances of all the seven algorithms decreased significantly under high solar zenith angles as compared to those under low-moderate solar zenith angles. For instance, for the OC4V4 algorithm, the relative percent difference (RPD) and root-mean-square error (RMSE) were 13.78% and 1.66 μg/l for the whole dataset, and 3.95% and 1.49 μg/l for the solar zenith angles ranged from 30° to 40°, respectively. However, the RPD and RMSE increased to 30.45% and 6.10μg/l for solar zenith angle larger than 70°.

Chlorophyll concentration is one of the important parameters of water quality assessment, and the quantitative retrieval of chlorophyll concentration and its distribution is one of the main applications of remote sensing in the coastal waters. Because of its unique geographical position and economic value, Hangzhou Bay has a very important research significance. By hyperspectral remote sensing technology effectively overcomes the effect of turbid coastal for chlorophyll concentration estimates, the researchers by accurate measurement of chlorophyll spectral characteristics of chlorophyll concentration for quantitative retrieval possible. The Hyperion hyperspectral imager for Hangzhou Bay estuary area of chlorophyll remote sensing monitoring data were chlorophyll a concentration in remote sensing inversion model is constructed, and combined with pretreated Hyperion high image data inversion of regional chlorophyll a concentration, and then analyzes the uneven distribution of Hangzhou Bay Estuary chlorophyll content space, near the Yangtze River Estuary and Hangzhou Bay estuarine research area of chlorophyll concentration is lower than that far from the coast in the study area, and the conclusion of regional autumn average CHL concentration is higher than in winter.

Currently, global sea surface salinity (SSS) can be retrieved by the satellite microwave radiometer onboard the satellite, such as the Soil Moisture and Ocean Salinity(SMOS) and the Aqurius. SMOS is an Earth Explorer Opportunity Mission from the European Space Agency(ESA). It was launched at a sun-synchronous orbit in 2009 and one of the payloads is called MIRAS(Microwave Imaging Radiometer using Aperture Synthesis), which is the first interferometric microwave radiometer designed for observing SSS at L-band(1.41 GHz).The foundation of the salinity retrieval by microwave radiometer is that the sea surface radiance at L-band has the most suitable sensitivity with the variation of the salinity. It is well known that the sensitivity of brightness temperatures(TB) to SSS depends on the sea surface temperature (SST), but the quantitative impact of the SST on the satellite retrieval of the SSS is still poorly known. In this study, we investigate the impact of the SST on the accuracy of salinity retrieval from the SMOS. First of all, The dielectric constant model proposed by Klein and Swift has been used to estimate the vertically and horizontally polarized brightness temperatures(TV and TH) of a smooth sea water surface at L-band and derive the derivatives of TV and TH as a function of SSS to show the relative sensitivity at 45° incident angle. Then, we use the GAM(generalized additive model) method to evaluate the association between the satellite-measured brightness temperature and in-situ SSS at different SST. Moreover, the satellite-derived SSS from the SMOS is validated using the ARGO data to assess the RMSE(root mean squared error). We compare the SMOS SSS and ARGO SSS over two regions of Pacific ocean far from land and ice under different SST. The RMSE of retrieved SSS at different SST have been estimated. Our results showed that SST is one of the most significant factors affecting the accuracy of SSS retrieval. The satellite-measured brightness temperature has a higher sensitivity with SSS variation and better accuracy of SSS retrieval at higher SST. For the most open oceans where surface salinity is typically greater than 32 psu, the sensitivity is around 0.2-0.25 K/psu for both vertical polarization and horizontal polarization when SST is 5°C,and the TB is more sensitive to the SSS for vertical polarization than horizontal polarization with the increase of SST. When SST increases to 30°C, the sensitivity is around 0.8 K/psu for vertical polarization which is about 40% larger than it of the horizontal polarization. In addition, the result of GAM model indicates that satellite-measured brightness temperature has better correlation with in-situ SSS at higher SST. The mean absolute error of the SMOS-derived SSS is around 0.9 psu when SST is 15°C, and decreases to 0.4 psu when the SST is 30°C.

Development and operational planning for ocean color satellite requires lots of careful consideration of the spatial and radiometric performance, which are represented by modulation transfer function (MTF) and signal-to-noise ratio (SNR) respectively. Those representative values are crucial indicator of sensor performance so that small changes of ocean properties (e.g., remote sensed reflectance (Rrs), surface chlorophyll-a concentrations (Chl-a), and so on) can be quantified and directly related with those values. MTF is affected from a performance of instrument itself and environmental conditions, and its variation leads to change the final products. The goal of this study is to simulate and to analyze the relationship between MTF parameter and ocean product variations, and then to provide a reference for the design of future ocean color sensors. In this study, we used the Geostationary Ocean Color Imager (GOCI) data to generate the simulated atmospheric correction band image. And then Rrs data and ocean products were generated with imagery from two different locations and acquisition times, and we analyzed and compared the statistical results with study area having different characteristics. For ocean products relationships, we notify the linear variation of the absolute percentage difference (APD) according to the changeable MTF value. Especially, Case-II water (turbid water) area shows more sensitive variation than Case-I water (clear water) area. Even though the same area was applied in the simulation, it was 1-2 times higher sensitivity of variation when a specific ocean phenomena such as red tide. The suggested simulation can be confirmed the relationship between blurred NIR band image and ocean products. And statistical results with MTF values were able to help estimating ocean product precision and designing a future mission such as the Geostationary Ocean Color Imager-II (GOCI-II) mission currently being progressed.

The influence of temperature variations on the determined concentrations of dissolved organic matter (DOM) in water was investigated by laser induced fluorescence (LIF) technique in laboratory. The effect of temperature on CDOM fluorescence was investigated in freshwaters of Xixi River and in aqueous standards. The total luminescence spectra (TLS) of CDOM in several types of water samples with laser-induced fluorescence (LIF) measurements using a 405 nm wavelength excitation source were measured in the laboratory. A temperature calibration equation was derived to standardize CDOM fluorescence measurements to a specific reference temperature. Laboratory experiments with a portable LIF LiDAR showed that CDOM fluorescence intensity decreased as ambient water temperature increased. High correlation (R²=0.91) was observed between concentration of CDOM and fluorescence normalized to water Raman scattering with the temperature calibration method. The results demonstrated that temperature calibration is a necessary and important aspect of CDOM monitoring using in situ fluorescence sensors.

The Persian Gulf and the Gulf of Oman locate at the northwest of the Arabian Sea, with the total area more than 50,0000 km². The Persian Gulf is a semi-enclosed subtropical sea with high water temperature, extremely high salinity, and an average depth of 50 meters. By the Strait of Hormuz, the Persian Gulf is connected to the Gulf of Oman which is significantly affected by the monsoonal winds and by water exchange between the Arabian Sea and the Persian Gulf. Algal blooms occurred frequently in the Persian Gulf and the Gulf of Oman, and some of them are harmful algal blooms which may lead to massive fish death and thereby serious economic loss. Due to the widely spatial coverage and temporal variation, it is difficult to monitoring the dynamic of the algal bloom based on in situ measurement. In this study, we used the remote sensing data from the Moderate Resolution Imaging Spectroradiometer (MODIS) onboard the Aqua satellite to investigate a massive algal bloom event in the Persian Gulf and the Gulf of Oman during 2008-2009. The time series of MODIS-derived chlorophyll concentration (Chl-a) indicated that the bloom event with high Chl-a concentration (~60 percent higher than corresponding climatological data) appeared to lasting more than 8 months from autumn of 2008 to spring of 2009. In addition, the bloom was widespread from the Persian Gulf to the Gulf of Oman and neighboring open ocean. The MODIS-derived net primary production (NPP) collected from MODIS showed the same trend with Chl-a. Multiple forces including upwelling, dust deposition was taken into account to elucidate the mechanisms for the long-lasting algal bloom. The time series chlorophyll concentration of the Persian Gulf emerges a significant seasonal pattern with maximum concentrations seen during the winter time and lowest during the summer. It also indicated slight disturbances occurred in June (May/July) and December (November/ January) in some years. The sea surface temperature and water transparency in the Persian Gulf increased with the rates of 0.3% (<0.01) and 3.02% (p<0.01) during 2003-2014, respectively. Chl-a and NPP declined with the rates of 1.61% (p=0.06) and 1.09% (p=0.08), respectively. However, there are no significant changes of the bloom initiation, termination and duration time among years over 2003-2014.

The electromagnetic (EM) scattering features of radar scattered echoes from nearshore sea surfaces are investigated using the second-order small-slope approximation (SSA-II). The joint influences of wind fetch and water depth on the normalized radar cross section (NRCS) of and Doppler spectra for echoes from nearshore sea surfaces are mainly studied. The numerical results show that with a further increasing fetch, the excess of NRCS for small depth sea over that for deeper sea increases, and Doppler spectral features are also intensely influenced by nonlinear interactions between waves in the large wind fetch and small water depth marine environment. These both indicate that the effects of the finite depth are more prominent with increasing wind fetch, especially for HH polarization.

A coordinated retrieval method for sea surface salinity based on SMOS and ocean color data was developed. The method retrieved sea surface salinity in open sea based on SMOS data, and those with much RFIs in the coastal area using ocean color data, a_CDOM. Tight relationships between surface water salinity and in situ a_CDOM were found during the cruises in the Yangtze River estuary on April 2013 and Hangzhou Bay in May 2014, distributions of a_CDOM revealed gradual downward trends of magnitudes, as water flowed down the Yangtze River estuary into the ECS coast. A dilution process was detected as water flowed down the Yangtze River and into the ECS coast. Thus, a salinity inversion model from the negative relationship between salinity and a_CDOM was developed firstly. Then we matched the SSS products with different spatial resolution retrieved based on SMOS and ocean color and combined them. In the end, we compared the SSS measurements between those based on only SMOS data and those based on method in this paper, and found that the method can make up the phenomenon of lack of data effectively.

The measurement of hyperspectral diffuse attenuation coefficients (K_d(λ)) in shallow turbid waters cannot be successfully achieved by the original Satlantic profiling system, because of less data available in the near-surface waters due to the rapid decrease of light intensity. In this paper, an improved profiling system and processing method are proposed. Firstly, a convenient buoyancy device is designed and mounted on the Satlantic Profiler II to allow the profiler to loiter close to the sea surface, thereby significantly improving the vertical sampling resolution to 1cm/s in near-surface waters, particularly in the depth between 0 and 1 meter. In addition, customized processing software CProSoft is developed to subjectively select the depths for various wavelengths that meet their different requirement for regression analysis. Comparison with original system results shows that our novel method can significantly improve the accuracy of K_d(λ) measurements especially in the short blue and red spectral range, and can even effectively derive near-surface K_d values in the extremely turbid waters with attenuation coefficients greater than 30 m^-1, which dramatically enlarge the K_d(λ) measuring range

In order to obtain the spectral information of objects and improve the retrieval of quantitative parameters from remotely sensing data accurately on land or over water bodies, atmospheric correction is a vital step, certainly, it is also a prerequisite to hyperspectral imagery data analysis approaches. On the base of previous studies, the atmospheric correction algorithms were divided to two categories: image-based empirical and model-based correction methods. The Quick Atmospheric Correction (QUAC) and Dark Object Subtraction (DOS) methods belong to the empirical or semiempirical methods, however, the Fast Line-of-sight Atmospheric Analysis of Spectral Hypercube (FLAASH) method was developed from the radiative transfer model. In this paper, we initially evaluated the performance from Hyperspectral Imager for the Coastal Ocean (HICO) of 16 Nov 2013 using QUAC, DOS, and MODTRAN integrated in FLAASH, and compared the results of these correction methods with in situ data. The results indicate that the method of FLAASH model performs much better than DOS and QUAC in atmospheric correction for HICO hyperspectral imagery, although the DOS and QUAC method is conducted more easily and do not require inputs of complex parameters.

The significant wave height can be measured only on the track of satellite observation, while wind field can be obtained on the whole satellite scan-view region. In this paper, the wind speed retrieved from the HY-2 Scatterometer and significant wave height con-observed from the HY-2 radar altimeter are used to analyze the wind-wave relationship over the western north Pacific and China seas on July 2015. The significant wave height, which is measured from altimeter, is defined as the average height of the highest one-third waves in a wave spectrum, which is the mixture of swells and wind-waves. In order to deeply understand the wind-wave relationship, we use the criteria that is the total amount of energy contained in the wave field is less than or equal to the wave energy for a fully developed sea in terms of wind speed U₁₀. Some the wind speed and significant wave height data eliminated the effect of swell are selected to study the wind-wave relationship, a second-degree polynomial wind-wave relationship is presented. It reveals a nonlinear relationship with the standard error is 0.59m, and it has an approximate linear relationship above 10 m s^-1. Those make it possible to get the wind-generated wave information from the satellite-based wind fields. This relationship is coincident with the other two wind-wave models from in situ observations and significant wave height of wind-generated wave is also predicted from the HY2-SCAT wind speed based on this wind-wave model. However, it is still required to be validated by more observations for the wind-wave model, and it is possible to better or operationally apply for wave forecasting based on satellite-retrieved wind speed.

This paper evaluates the rain effects on Ku-band radar backscatter at low incidence angles. The data used consisted of the sea surface backscatter and averaged rain rates from Tropical Rainfall Mapping Mission precipitation radar (TRMM PR) measurements and the collocated 10-m height numerical prediction wind speeds from the European Centre for Medium-Range Weather Forecasts (ECMWF). The wind-induced backscatter was estimated by the Ku-band low incidence backscatter model (KuLMOD) and possible bias due to different wind speed inputs was considered. The rain effect was analysed by comparing the TRMM PR-measured surface backscatter for the rain-affected sea surface with the collocated wind-induced backscatter. We found that the surface backscatter decreases with increases in the averaged rain rate. The rain-induced backscatter was clearly dependent of the wind speed and was slightly dependent of the incidence angle. Results show that it is necessary to develop a wind and rain backscatter model instead of single wind backscatter model.

The beam attenuation coefficient (c), an inherent optical property of water, can provide information about the particulate matter in the water. In this study, the vertical distribution of the particulate beam attenuation coefficient at 660 nm (c_p(660)) and its correlation to the particulate organic carbon (POC) and chlorophyll a (Chl-a) concentrations in the north South China Sea (NSCS), was investigated based on the in situ data from two cruises covering the summer and autumn seasons during 2009-2010year. The results showed that in summer, the profiles of c_p(660) at the near shore stations were generally well vertical mixed, except at the bottom layer where c_p(660) sharply increased due to sediment resuspension. However, in the slope and basin, the profiles of c_p(660) had the peak value in the subsurface layer, and the depth of maximum increased with the increasing of the water depth. The subsurface maximum of the c_p(660) was corresponding to the subsurface maximum Chl-a in the shelf and basin in the NSCS in summer. In autumn, the depth profile of c_p(660) was also well mixed in the near shore, similar as it in summer. In the basin, unlike the subsurface maximum in summer, c_p(660) had the decreasing trend with the increasing of depth in most stations in autumn. The spatial distribution pattern of the surface c_p(660) was similar in the two seasons, with high values in near shore and low values in the shelf and basin. This was mainly attributed to the river and terrigenous organic materials. There were good correlations between c_p(660) and POC in both seasons, except some near shore stations with high sediment resuspension. That made the possibility of estimating the POC profile using the c_p(660), and further calculating the vertical structure with satellite-derived surface POC.

Results of satellite observations of surface manifestations of internal waves in the Caspian Sea are presented. Our work produced data on a spatial and temporal variability of internal waves of non-tidal origin via their surface manifestations. By using high-resolution satellite data, we were able to get a clear picture of generation, propagation and interaction of internal wave packets and significantly broadened our insights on the physics and geography of internal waves in the World Ocean. The large amount of the data available allowed us to make some generalizations and obtain statistically significant results on a spatial and temporal variability of various internal wave surface manifestations in satellite images. We discovered numerous diverse instances of internal wave manifestations in satellite images of the Caspian Sea. We further demonstrated that this observed diversity of internal wave behavior is due to a diversity of their generation mechanisms and indicates the complexity of the dynamic environment in the region. We put together a detailed map of spatial distribution of surface manifestations of the internal waves in the Caspian Sea. We revealed a seasonal and inter-annual variability of wave activity, identified main regions of the internal wave localization for each season and revealed causes of a spatial inhomogenity of internal wave packet manifestations. Possible factors leading to the generation of non-tidal internal waves are determined on the basis of joint analysis of available satellite remote sensing data of the sea surface in microwave, visible (VIS) and infra-red (IR) ranges complemented by contact measurements.

Synthetic aperture radar (SAR) is an active instrument which is used to create images of an object. Underwater bottom topography can be retrieved indirectly by measuring variations of the sea surface roughness in the SAR images, although the microwaves cannot penetrate into the water. In this paper, we present a new simple method for bathymetric mapping in the shallow sea. Based on the radiometric correction, sea surface roughness is derived using SAR images. These results are then used for water depth inversions based on the Alpers-Hennings (AH) model, supported by a few true depth data points (sounding data or chart data). This method is used to bathymetric mapping of two areas in the Subei shoal. The study results of the two cases show that the trend of the inversion and true depths match well. The retrieval accuracy depends on the true depth data points. In a case, the true depth data is the sounding data, the relative errors between the inversion and true depths is less than 20%. In the other case, the true depth data is the chart data. And the result is worse, because the measure time of the chart is 1979, and the time of SAR images are 2000s. The bottom topography was changed. The proposed method has two advantages in that it does not require environmental parameters and it is relatively simple to operate.

At present a sufficient amount of methods is offered for determining the characteristics of sea roughness in accordance with optical images of wavy water surface obtained from different near-shore constructions, sea platforms, vessels, aircraft and satellites. The most informative elements in this case are solar path and peripheral areas of the image free from sun glitters. However, underwater images of the surface obtained with the help of optical receiver located at a certain depth contain apart from the mentioned elements one more informative element– Snell’s window. It is an underwater sky image which distortions of border contain information on roughness characteristics and serve as the indicator of its variability. The research offers the method for determining energy spectra of wind waves in accordance with the second statistical moment of Snell’s window image. The results of testing of the offered method are provided based on natural images registered in the course of trip to the Black Sea under conditions of different wind and wave environment for clear surface and surface covered by surfactant films. For both cases frequency spectra of surface slopes are recovered and their good coincidence to the spectra received by processing of signals from a string wave recorder is established. Efficiency of application of the offered method for tasks of remote monitoring and environmental control of natural reservoirs is shown.

The National Development and Reform Commission of China has approved a large number of nuclear power projects, with a total capacity of 23,000 MW. However, concomitant with the accelerated development of nuclear power stations, the environmental effects of thermal discharge will become a problem that cannot be avoided. Real-time monitoring of water temperature needs to be installed following station construction in order to measure its variation with time and to ensure that the operation of the nuclear plant does not result in adverse environmental damage. Landsat is the world’s oldest, continuously acquired collection of space-based, moderate-resolution, land remote sensing data. On May 30, 2013, data from the Landsat 8 satellite became available, and the data quality and radiometric quantization of the thermal infrared sensor (TIRS) are significantly greater than those of previous Landsat instruments. The analysis of sea surface temperature (SST) obtained from Landsat 8’s TIRS data was used to enhance information about the plume shape, dimensions, and direction of dispersion of the thermal discharge from the Qinshan Nuclear Power Plant in Hangzhou Bay on the East China Sea coast. Both single-channel and split-window algorithms were used and focused. The detection of temperature increases through split-window algorithms is considered a preferable method for warm discharge monitoring. Recent results showed that the thermal discharge from the nuclear plant was controlled over a small area, and that it never breached national water quality standards.