Pavel A. Salyuk

Optical properties of Peter the Great Bay waters compared with satellite ocean colour data

The shipboard measurements of optical and hydrological properties of seawater were used for development of regional bio-optical algorithms of waters of Peter the Great Bay. The shipboard measurements of chlorophyll-a and dissolved organic matter (DOM) concentrations were obtained by flow-through laser fluorometer (LF-3) (Institute for Automation and Control Processes, Vladivostok, Russia) and Sea-Bird Profiling CTD SBE-19plus (Conductivity, Temperature and Depth Sea-Bird Electronics, Sea-Bird Electronics, Inc., Washington, USA) equipped with WetStar fluorometers (WET Labs, Oregon, USA). The measurements were optically weighted according to light attenuation by depth. Ocean colour Moderate Resolution Imaging Spectroradiometer (MODIS)-Aqua data were used for our comparative analysis. Chlorophyll-a concentrations from ocean colour data were retrieved by OC3M, Garver-Siegel-Maritorena (GSM) and Carder algorithms. Relationships of the shipboard and satellite sensor data were analysed comparatively in our work. The Carder model gives the most general results of estimation of chlorophyll-a concentrations for all observed water cases. OC3M and GSM algorithms show good performance in case I water but they have large errors in the Amur Bay waters because of a large impact of the Razdolnaya river and Vladivostok city anthropogenic activity. Two regional chlorophyll-a algorithms were offered and they improve significantly the accuracy of chlorophyll-a concentration estimation. The first one is based on empirical regression between chlorophyll-a concentration and remotely sensed reflectance ratio. The second one uses satellite-derived values of sun-induced chlorophyll-a fluorescence when chlorophyll-a concentrations are higher than 3 mg m−3. The last one gives the best results for all water cases and provides an approach for separation between DOM produced by phytoplankton and DOM not connected with phytoplankton activity. This allows a regional DOM algorithm to be made.

Mobile hyper spectral optical complex for under satellite ocean research

This paper presents the mobile complex to perform continuous measurements of chlorophyll-A concentrations and dissolved organic matter by the laser induced fluorescence method. The obtained data allow evaluating the state of the photosynthetic system of phytoplankton cells. In addition, the complex allows recording the CO2 gas analyzer data, the sea water saltiness sensors, pH, temperature, and solar illumination meter. The mobility this complex ensures a possibility working on different ships and under stationary conditions. The configuration of the complex can be promptly changed for solving the current problem by promptly adding or replacing various devices and sensors. The developed software integrates all devices into the complex. The enclosure of system allows use of conventional laboratory equipment, which is resistant to vibration, but not protected from the effects of the marine environment. Results of in situ measurements performed in Sea of Japan (Peter the Great Bay) by experimental setup are given.

Use of laser induced fluorescence method for phytoplankton communities describing

THe seawater flurescence spectra were measured by laser induced fluorescence (LIF) method. ND:YAG laser with frquency-doubled output at 532 nm was used to induce the fluorescence. The laser fluorometer measured the fluorescence spectral distribution in the band from 540 nm to 740 nm. Chlorophyll-a concentration and conventional concentration of dissolved organic matter fluorescence (FDOM) in wavelength range from 560nm to 740nm wer calulated from LIF spectra. The correlation coefficient between chlorophyll-a and FDOM concentrations was calculated in the floating window along ship track. High value coefficient means that FDOM produced by phhytoplankton living on the investigation sea area at the given time interval. Chlorophyll-a-FDOM relationships were described by linear regression. Intercept coefficient is a background FDOM (or FDOM do not produced by phytoplankton living on the investigation sea area in given time interval) and the slope coefficient is FDOM productivity by one μg/l of chlorophyll-a of phytoplankton. The clusters were determined from calculated slope, intercept and correlation coefficients. The clusters correspond to phytoplankton communities and calculating coefficients characterize condition and the evloution stage of these phytoplakton communities.

Performance of satellite regional bio-optical algorithms depending on relationships between chlorophyll-a and dissolved organic matter concentrations

The validity of satellite regional algorithms depends on variability of optical properties of coastal waters and especially on relationships between concentrations of chlorophyll-a (chlA) and dissolved organic matter (DOM). The subject of the current researches is the role of characteristics of clusters in chlA - DOM scatter plot while developing of the regional biooptical algorithm. Regular undersatellite shipboard measurements of chlorophyll-a and DOM concentrations by means of contemporary laser fluorometer obtained in the various regions of Peter the Great Bay from 2007 to 2010 were used for the analysis.

Radiative components dynamics at the Far East region

This document is a review of our investigations of the atmosphere and ocean radiative components are presented. Paper is focused on three major factors must taken into account at the Far Eastern region. The first is atmosphere aerosols, the second - ozone and the third - phytoplankton communities. Here we discuss how aerosols are distributed in the atmosphere (spatiotemporal characteristics), how they interacts with other atmosphere constituents, its impaction on cirrus clouds formation. We also present atmosphere ozone layer dynamics and its wintertime specific features, discuss primary and secondary maxima evolution and causes of secondary maximum formation.

Characterization of phytoplankton communities by laser induced seawater fluorescence measurements

The results and methods obtained in one round-the world sea expedition and several north-western Pacific expeditions are presented. Measurements of hydrological and bio-optical parameters of seawater were carried out. It was used method of ship-borne laser-induced fluorescence realized in flowing variant which allow to conduct measurements during ship movement. In some expeditions in-depth fluorescence measurements were obtained with the help of fiber add-on device and in some cases two excitation wavelengths were used (355 and 532 nm). Dissolved organic matter (DOM) fluorescence - chlorophyll-a fluorescence scattering diagrams were investigated in various seawater areas of Oceans in different algae development stage. Procedure of phytoplankton communities characterization were offered, it is based on the data of hydrological measurements and on the parameters of linear regression between chlorophyll-a and DOM fluorescence. It was shown that significant linear correlation between chlorophyll-a fluorescence and DOM fluorescence induced by 532 nm Nd:YAG laser radiation generally observed during algae blooming and for all waters with chlorophyll-a concentration upper then 5 ug/l. The procedure can be used for flowing fluorometers or LIDAR fluorometers which allow to conduct measurements from moving carrier with spatial resolution better then 500 m.

Automatic identification of various spectral features at the time-resolved excitation emission matrix of dissolved organic matters and phytoplankton cells in seawater

The variation of the different parameters of the exciting radiation and the registration of the fluorescence of the investigated object allows to obtain multidimensional spectral images: from three-dimensional (length of the exciting radiation, the wavelength of the emitted radiation, the fluorescence intensity) to eight and more dimensions (in addition to three of these dimensions: spatial coordinates x, y, z; time of measurements; the duration and the intensity of the exciting radiation and etc.). In the case of measurements in natural conditions is highly desirable that the result of the processing performed during a single measurement for the operation in real time. In this paper we consider the approach described for the treatment of fluorescence measurements of dissolved organic matter and chlorophyll-a in seawater. Joint analysis of the various pairs of wavelengths of excitation / emission fluorescence, fluorescence analysis at different durations of the exciting radiation and the time-spatial analysis of the received signal allow identifying different types of fluorescent dissolved organic matter and estimate their stage of biodegradation, to study the functional state of phytoplankton cells. So it is possible to provide real-time investigation of environmental indicators of seawater.

The equipment for time-resolved measurements of excitation-emission matrix of seawater fluorescence in natural conditions

Excitation-emission matrix (EEM) technique is widely used to study the properties of organic matter in seawater. Additional variations of the exciting radiation parameters (in addition to the wavelengths), such as duration and intensity, allow to get more spectral information about the object of research, and allow to identify some individual components or to study the dynamics of the molecular changes in the sample of analyzed liquid. One of the main limitations of the EEM is that usually necessary to carry out research in the laboratory on the specialized equipment. The paper describes the hardware system allowing carry out measurements in the field studies. The hardware system includes a set of light-emitted diodes (LEDs) working in the range from 245 to 600 nm, which produce sequential excitation fluorescence of the sample liquid, which is detected using a 32-channel photomultiplier tube (PMT). Number of LEDs can vary from 7 to 16. Through the use of multi-channel photomultiplier reached the required measurement sensitivity and efficiency measurement is less than 1 minute for full cycle. Minimum 4 channel in excitation range of 350-600 nm support the work of variable duration excitation pulses from microseconds to seconds. It makes possible to measure the fluorescence of the chlorophyll-a with closed or open reaction centers of phytoplankton cells. The use of multiple excitation radiation allows to activate various mechanisms of energy transfer in the photosynthetic apparatus of phytoplankton cells, improves measurement accuracy, reduces dependence on the variation in species composition and functional state of phytoplankton.

Optimization of the search algorithm for the shortest route

The exact and heuristic algorithms of search of the shortest routes on the graph are analyzed in the article. The realization of Floyd-Warshall algorithm of search for the shortest routes is shown. The description and realization of the authors heuristic algorithm of search for the shortest route for two chosen vertexes of graph for the given heuristic estimated function is given.

Method of forming the estimated vector for sections of the shipping route

The article presents formalization of the problem of determining the optimal shipping route based on graph and multi-criteria optimization theory. Methods of forming weight coefficients for sections of the shipping route are shown. Possible target functions and optimization criteria based on predetermined factors are listed.