The results of pioneering long-term observations of the surface layer salinity of the Black Sea by means of two drifters deployed in April 2021 are presented. The surface salinity is restored based on data from simultaneous measurements of the speed of sound and the temperature of seawater, which ensures the preservation of the metrological characteristics of the measuring channels under conditions of biological fouling. Analysis of synchronous observations of two buoys indicated that the calculation error of salinity was in the range of ±0.03‰. The variability of the surface layer salinity according to one of the drifters from April 14 to August 2, 2021, was compared with the salinity along the trajectory of the drifter, based on the analysis of the marine forecast service of the Copernicus program. The general trends in salinity changes according to observational and analytical data correspond quite well to each other. At the same time, a number of significant inaccuracies were revealed in the analyses of the marine forecast service in the gyre centers and in the areas of surface fronts.

Purpose. Reliability of knowledge about the ocean dynamics and climate variability is largely limited for lack of systematic in situ observations of the sea surface layer salinity, which is one of the basic hydrological parameters determining circulation and stratification of the water masses. The study is aimed at developing an autonomous device for long-term monitoring of salinity in the seawater upper layer. Methods and Results. One of the most effective tools for in situ observations of the ocean upper layer is the global network of surface drifting buoys – drifters. At present, the network consists of more than 1500 buoys, but only a few of them provide sea surface salinity observations within the framework of a limited number of pilot experiments. In the drifters, salinity is calculated by the traditional method using the results of the electrical conductivity and temperature measurements. There are a few problems related both to the principle of determining salinity by this method and to providing long-term stable running of conductivity sensors under the conditions of pollution and biological fouling. A drifter equipped with the module for the sound velocity and temperature measurements used for calculating salinity by an alternative method just aboard the drifter, was developed in Marine Hydrophysical Institute, Russian Academy of Sciences. The sound velocity and temperature module includes a specially designed time-of-flight sound velocity sensor with the fixed base and a quartz temperature sensor. In course of two years, numerous laboratory and in situ tests of several prototypes of the sound velocity and temperature module were performed. The laboratory tests showed that the repeatability limits for the results of the sound velocity measurements in the distilled water were 0.02 m/s. According to the data of the long-term in situ tests performed at intensive biological fouling, the error of salinity estimation resulted from of the sound velocity and temperature measurements were within 0.05 ‰. This result permits to expect that the sound velocity and temperature module parameters will remain stable in real conditions of long-term autonomous operation. Conclusions. The obtained results make it possible to recommend application of the drifters equipped with the modules for the sound velocity and temperature measurements as an effective tool for regular operational monitoring of the salinity field of the upper sea layer.

The article presents the results of the study of ways to create distributed measuring networks to control the parameters of the surrounding coastal marine environment and atmosphere. The device, the principle of operation and the measuring capabilities of the meteorological station and the measuring buoy are considered. An example of an intelligent hydrometeorological adaptive system for controlling the parameters of the coastal water area is presented.

Purpose. The geographical and climatic features of the Crimean Southern coast condition significant dynamic activity of the water thermal structure. Studies of the temperature vertical variability in the absence of the tides’ dominant affect, permit to specify the upwelling structure and dynamics as well as the characteristics of waves of various origin. Such hardly-forecasted processes, the time scales of which constitute from a few minutes to several days can be revealed and registered only by long-term continuous observations. The aim of the study is to analyze the results of long-term monitoring of the thermal processes in the coastal zone near the Crimean Southern coast. It was performed at the Black Sea hydrophysical scientific polygon. Methods and Results. In December, 2012 the observation system for operational control of the water temperature vertical distribution was installed at the stationary platform located in the coastal zone of the Black Sea (the Blue Bay) at a distance of ~450 m from the coast. The sea depth under the platform was ~30 m. Digital temperature sensors having precision better than 0.1 °C were installed with 1.5 m intervals in the temperature string of the system. The profiling period was 60 s. The 6.5 year-long experiment with the observation system provided statistically significant and duration-unique serious of data on variability of the thermal processes in the sea coastal region. By early April 2019, the total duration of the system productive functioning was ~900 days. During this period, more than 1300000 temperature profiles were obtained. Based on the data obtained in 2013, the estimates of a seasonal cycle of the temperature synoptic variability are represented. The upwelling events not related to the wind impact are considered. Conclusions. The long-term data series resulted from the multi-year experiment permit not only to specify, but also to change some of the existing ideas of the thermal processes’ evolution features in shelf zone of the Black Sea. Noted is the expediency of applying the observation system as a segment of the constantly operating network at the coastal polygons for performing hydrophysical measurements in the Black Sea.

A study of creating the adaptive measuring networks with intellectual setting of the temporal resolution of measurements based on the technology of «Marine Internet of Things» is considered. Analysis of existing satellite communication systems showed that to build a global distributed network with two-way communication based on small-size autonomous measuring platforms, there is only the Iridium communication system. An intelligent adaptive system for water level monitoring in the reservoir is presented.

The engineering and operational features of the satellite trackers iceST/40-Glacier developed in the Marine Hydrophysical Institute, Russian Academy of Sciences, and produced by Marlin-Yug Ltd are considered. The trackers are developed to monitor the glaciers' movements. The glaciers' motion characteristics are calculated using the tracker coordinates measured by the satellite GPS receiver and distributed among the users due to the worldwide location and data collection system Argos-2. The satellite tracker construction is simple enough to place it on a glacier. It represents a specially developed measurement algorithm that permits, first, to apply a standard low-cost GPS receiver and, second, to define location with accuracy not exceeding 1.7 m. The measurements required to determine location are done once a week. The tracker lifetime is not less than 24 months. Statistical analysis of the long-term field experiments carried out on the Arctic archipelagos' glaciers results in drawing a conclusion that, the iceST/40-Glacier satellite trackers, being used as a basis, make creation of reliable, technological and low-cost network for regular monitoring the glaciers' movements possible and expedient. The information obtained due to such a network permits to increase navigation safety in the Arctic Ocean marginal seas and can be used for verifying remote sensing data.

In the early 70s, 20th century, the tools for studying the World Ocean (besides the already existing research vessels equipped with celestial navigation) were expanded with automatic buoys and remote sensing technologies. The first idea was to create the global observing system on basis of large quantity of surface mooring buoys, equipped with hydrological and meteorological equipment. The evaluation of this suggestion revealed the fact that such tool was too expensive. It was decided to construct a network on the basis of drifting buoys which are significantly cheaper. The article shows the results of scientific and practical efforts to perform a step by step development of the drifter technology, which is the main instrument for global observation in the Ocean now.The cycle of works executed from 1973 to 2016 provided a creation of a world-class drifter technology for solution of different scientific and practical challenges. The research results are actively used for the needs of the Russian Federation and the global drifter program. The prospect of future works is related to the national challenges on the research of the Arctic and other World Ocean regions, participation in national and international projects on calibration of satellite onboard systems for the Earth remote sensing and also to validation of numerical simulation results for refining the marine environment variability forecast.

The constructional and operational features of the BTC60/GPS/ice temperature-profiling drifters, developed in Marine Hydrophysical institute RAS for investigation of polar areas, are considered in this article. The drifters operated in completely automatic mode measuring air pressure, water temperatures at 17 depths down to 60 m, ocean pressures at 20, 40 and 60 m nominal depths and current locations. Accuracies of measurements were: +/-2 hPa for air pressure, +/-0.1 degrees C for temperatures, +/-30 hPa for ocean pressure, 60 m for locations. Iridium satellite communication system was used for data transfer. Time delay between sample and delivery to a user did not exceed 10 minutes. More than 30 thermodrifters were developed in the Beaufort Sea - Canada Basin and central Arctic for the period from September 2012 to September 2014. Total duration of drifting buoys in operation was more of 4800 days. It was accepted the data of hourly samples about variability of ice-flows and ice field as a whole movements, therm degrees processes within upper water layer below ice, air pressure in near surface atmosphere of the Arctic region. The article includes some results of statistical analysis of data from drifter ID247950, the 3-year trajectory of which depended on the processes of transfer and evolution of ice fields in the Beaufort Sea - Canada Basin. Over a long period of time the Arctic buoy in-situ experiments allowed resulting about capability and reasonability to create reliable, technological and low-cost buoy network on basis of BTC60/GPS/ice drifters to monitor Arctic area of the World Ocean.

В работе выполнена валидация восьми международных продуктов оперативного спутникового мониторинга температуры поверхности моря c высоким пространственным разрешением: CMS_L3 (Франция), CNR (Италия), OSTIA (Великобритания), CMC (Канада), DMI (Дания), GAMSSA (Австралия), ODYSSEA (Франция), NOAA (США).Натурные измерения поверхностной температуры Черного моря осуществлялись автоматическими поверхностными свободно дрейфующими буями (дрифтерами) типа Iridium SVP-BTC80RTC/GPS.С целью устранения влияния ошибок, связанных с дневным прогревом поверхности, валидация проводилась по ночным измерениям температуры и в холодное полугодие -с ноября 2013 г. по март 2014 г.Наименьшую погрешность восстановления температуры поверхности Черного моря обеспечивают массивы OSTIA (среднее отклонение -0,14°C, среднеквадратическая ошибка 0,24°C), GAMSSA (среднее отклонение -0,05°C, среднеквадратическая ошибка 0,28°C) и CMC (среднее отклонение 0,06°C, среднеквадратическая ошибка 0,30°C).На точность восстановления температуры поверхности моря влияют как ошибки алгоритма восстановления, так и природные условия.Дистанционное зондирование районов со сложной гидрологической обстановкой (распреснение черноморских вод речными, установление и таяние льда) или аномальными атмосферными условиями (нетипичное вертикальное распределение или количество водяного

Efficiency of the problem solution to create a regionally-oriented data computing system for marine dynamics and ecosystem evolution modeling and forecasting (that should be capable for providing reliable information for managerial decision making, justifying future economic projects and adjusting the existing ones) depends on development level of observational systems, environmental evolution, mathematical models and techniques for observational data assimilation. The analysis of the system as an observational segment of modern geo-informational technology allows us to draw a conclusion that the system of drifter observations is one of the most effective ones nowadays. Surface drifter network, continuously operating in the World Ocean, provides systematic operational data on the surface water circulation, thermal processes in the upper ocean and air pressure. Drifter data, acquired over the past 15 years, allowed one to improve and even change the existing concepts of patterns and mechanisms of regional climatic trend and hydrometeorological anomaly formation under effect of global processes in the Ocean – Atmosphere model (in the high latitudes as well). In the present paper the principle results of the analysis of expediency and feasibility of drifting systematic operative pressure field monitoring establishment in the near-surface atmosphere layer over the Arctic Ocean and the seas of the Russian Federation Arctic Zone have been considered. More than 30 drifters of BTC60/GPS/ice type, whose summarized lifetime as for June 2015 exceeded 6500 days, were deployed in the Arctic in 2012–2015. According to data acquired from the drifters, more than 155 000 air pressure readings were received. The most intensive drifter observations were carried out in two regions: in the Beaufort Sea – Canada Basin and in the Central Arctic. The results of experiments revealed that hardware-software solutions implemented in polar modifications of barometric drifters provide reliable long-term operation of these apparatus as autonomous instruments of air pressure field operative systematic monitoring in the Arctic Region. With regard to relatively low cost and acceptable dimensions and weights barometric drifters may be considered as the elements of reliable and low-cost polar network of operative meteorological observations.

The technical characteristics of the new satellite communication system Argos-3 are investigated with reference to the drifter experiments in the World Ocean and the Black Sea. A comparison of the standards of satellite communication systems Argos-2 and Argos-3 is carried out. The distinctive features of the Argos-3 from the previous generations of the system are greatly increased bandwidth and a significant reduction of the data equipment power consumption through the use of the reverse link for the guarantee of prediction of the satellite transmission and acknowledgment during the message transferring. In the context of the international pilot project "Argos-3 Pilot Project" the Argos-3 equipment performance is evaluated and its configuration is determined according to the insitu operation as a part of the marine drifting buoys (drifters). The results of in-situ experiments with new Argos-3 drifters and traditional Argos-2 drifters are compared and the performances of both systems are analyzed. The recommendations on the optimum configuration of the equipment Argos-3 as part of drifting buoys are given. The results of the laboratory and long-term field experiments have shown the efficacy of the solutions to adapt the surface drifting buoys to the satellite system Argos-3, developed in MHI и "Marlin-Yug Ltd" and which is now widely used to improve the global drift-monitoring network.

The technical characteristics of the new satellite communication system Argos-3 are investigated with reference to the drifter experiments in the World Ocean and the Black Sea. A comparison of the standards of satellite communication systems Argos-2 and Argos-3 is carried out. The distinctive features of the Argos-3 from the previous generations of the system are greatly increased bandwidth and a significant reduction of the data equipment power consumption through the use of the reverse link for the guarantee of prediction of the satellite transmission and acknowledgment during the message transferring. In the context of the international pilot project "Argos-3 Pilot Project" the Argos-3 equipment performance is evaluated and its configuration is determined according to the insitu operation as a part of the marine drifting buoys (drifters). The results of in-situ experiments with new Argos-3 drifters and traditional Argos-2 drifters are compared and the performances of both systems are analyzed. The recommendations on the optimum configuration of the equipment Argos-3 as part of drifting buoys are given. The results of the laboratory and long-term field experiments have shown the efficacy of the solutions to adapt the surface drifting buoys to the satellite system Argos-3, developed in MHI и "Marlin-Yug Ltd" and which is now widely used to improve the global drift-monitoring network.

Abstract. Regular observations in the Black Sea basin started in the past century, and quite good multidisciplinary observing system operated in the 70–80ies based on the ship observations. Modern oceanographic observing system in the basin is built according to the GOOS principles. It includes space remote sensing observations, data of free floating buoys and costal observational network. Integration of the observing system and its real-time operation were started within the framework of the FP5 ARENA project and later were improved during the FP6 ASCABOS project. The coastal observing system which includes time series from the coastal platforms and multidisciplinary surveys of the coastal areas fulfilled by the research vessels was set up during the ECOOP. Paper describes all components of the Black Sea observing system operated during the ECOOP project and its applications in the framework of the project.

The autonomous drifting buoys equipped with satellite link turn into one of the most important components of the global system of operative observations of the ocean and the surface layer of the atmosphere. However, on the regional level, the problem of analysis of the surface circulation of waters in the coastal zone and sea straits remains quite urgent because the available drifters cannot be used in this case due to their sizes and long intervals between measurements. We present the results of development and testing of a new drifter system aimed at measuring currents. The system is based on the use of buoys operating at depths less than 1 m. To improve the space-and-time resolution of measurements, the buoys are equipped with receivers of the global positioning system ( GPS ) and GSM modems for the data transfer via cellular communication networks. The drifter system guarantees the possibility of determination of the coordinates of buoys with a resolution of 3 min in time and 14 m in space. We describe the specific features of the design of the proposed information-and-measuring drifter system and present the first results of application of new buoys called “minidrifters” for the pilot monitoring of currents in the Kerch Strait.