This paper is devoted to the study of the possibilities of restoring the concentrations of chlorophyll-a (Chl-a) and total
suspended matter (TSM) in fresh waterbodies using the images of Sentinel-2 / MSI of the Gorky reservoir as an
example, validated via the high-resolution ground-truth data obtained by fluorescence lidar UFL. This water area in the
period of intense chromaticity of cyanobacteria is distinguished by their completely heterogeneous spatial-temporal
distribution with scales of patchiness from several tens of meters and high temporal variability. For this reason, direct
methods of “spot” measurements in place on water samples in a small part of the reservoir for 3 hours relative to the
satellite’s span do not provide us with reliable and statistically proved data. In this regard, the work proposed an original
method of high-performance sub-satellite synchronous measurements of the brightness of the water column,
concentrations of Chl-a and TSM with a fluorescent lidar onboard a high-speed vessel. This technique is provided with a
spatial (8 m) and a temporary (1 s) resolution. Based on this, 4 independent regional models for the recovery of Chl-a
concentrations, as well as TSM were developed based on in-situ measurements of the brightness of the water surface, or
from Sentinel-2 / MSI images. To ensure the possibility of using satellite images, the analysis of atmospheric correction
algorithms was performed and the best one was determined. The proposed models can be used for regular environmental
monitoring of the Gorky Reservoir according to the in-situ ship measurements of the brightness of the water surface or
from Sentinel-2 / MSI images. When using the proposed methodology for lidar high-performance collection of sub-satellite
data, the developed models can be adapted for limnological monitoring of other freshwater bodies with high
spatial and temporal variability of the optical properties of water.
An experimental study of statistical characteristics of fluorescent lidar echo signals and spatial distribution of optically active components in waters of the Gorky reservoir at 40 x 10 km experimental area covering the floodplain, channel and estuaries of inflowing rivers was performed. The measurements were carried out during 4 days from 1 August to 4 August 2017 and from 20 September to 22 September 2018 at the stations and continuously along the motorboat track with the help of fluorescent lidar UFL-9 which allows to restore concentrations of chlorophyll a, colored organic matter and total suspended matter in the upper water layer with thickness of about 0.2 to 1.0 m for eutrophic waters. This paper presents maps of their spatial distribution, demonstrating different scales of inhomogeneities, average values and spatial variability of chlorophyll a, total organic carbon and total suspended matter as well as data on variance and spatial spectrum of fluctuations of the elastic backscattering signal. Regressions between mean values and coefficients of variation of suspension and chlorophyll a, and between coefficients of variation of suspension and energy of the elastic backscattering signal are established.
The three-stage thermodynamical model of tropical cyclone generation is suggested. According to this model the
decisive role for tropical cyclone starting plays combination of the three following factors: high ocean surface
temperature, high value of air humidity and low wind velocity in the atmospheric layer above water surface. All these
parameters can be successfully measured by microwave radiometry methods, satellite microwave scanner data giving
the possibility to examine the distribution of these physical parameters over different aquatoria of World Ocean and to
follow their alteration within the day. A new complex criterion Ω was developed which we gave the name of Pelevin
criterion. It is calculated using the values of ocean surface temperature, water vapor amount in the air layer above water
surface and Carioles parameter that depends on the place latitude. The value of the criterion is shown to be proportional
to the probability of cyclones generation estimated by frequency of cyclones generation in the Indian and Atlantic
Oceans during the 1 6-year-period. Using the maps of monthly averaged ocean surface temperature and humidity of the
adjacent atmospheric air layer in the Atlantic and Indian Oceans the distribution of average values of Pelevin criterion
over these aquatoria is calculated. The obtained results give the possibility to explain seasonal and latitudinal
peculiarities of tropical cyclones generation.
Using data obtained in Canarian Upwelling, Black and Marmora Seas from board research ships of Shirshov Institute of Oceanology RAS the possibility of 'yellow substance' concentration determination in productive and polluted waters by one of the four optical methods was shown. The first method is based on the contact measurements of the vertical light attenuation coefficient at 500 nm with descending devices. The second method uses remote measurements of the sea-water radiance coefficient spectra from board a moving ship with three-channel spectrophotometer. The water type optical index is calculated from the obtained sea water radiance spectrum, then using the appropriate classification the main natural admixtures concentrations are estimated. According to the third method 'yellow substance' concentration is estimated from the measurements of sea water fluorescence intensity in blue-green spectral band (approximately 440 nm) by laser remote sensing of water surface in UV. The results of 'yellow substance' concentration estimation in sea water by these three methods were proved by the comparison with the concentration measurements data obtained by the two-ray laboratory photometer in filtrated samples of sea water taken at the stations.
The task of investigation of distribution in upper ocean waters of light absorbing and light scattering admixtures is of great interest for oceanology and, specifically, for appreciation of ecological state of sea waters and their contamination of human matters, first of all, by oil products. Among different measuring methods there are especially perspective ones -- methods of sea laser probing from ship's side without stopping of the ship, which allow to make 'simultaneous measures' in quite different voyages -- tourist, cargo, research cruises and etc. Measures (which did not request stopping of the ship), accompanied by taking of probes during motion for subsequent laboratory analyses were organized in the 53 cruise of R/V 'Akademik Kurchatov' around European continent (1994). The works of such type were executed also in the 26 cruise of R/V 'Vityaz' in Atlantic ocean (1991).
A new characteristic of the sea surface radiance spectrum is suggested as a parameter for the optical remote sensing. It gives the possibility of efficient estimation of light absorbing and light scattering admixture concentrations in sea-water being practically invariant to the affection of the atmosphere. This parameter is the gradient of the sea spectral radiance coefficient distribution within the band 490-510 nm. The investigation of this gradient dependence upon the type of sea water in the open ocean, as well as in the Mediterranean, Black and Baltic Seas was carried out. The results are given, showing the high informativity of the suggested parameter. It should be stressed that the atmospheric light scattering doesn't contribute much to this parameter by ocean remote sensing through the atmosphere. That's why the spectral gradient of sea- atmosphere radiance coefficient at about 500 nm can be used for sea monitoring practically without atmospheric correction.
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