The interannual variability of the World Ocean mean level, according to altimeter data was 3.35 ± 0.4 mm/year at a 90% confidence interval, and the trend acceleration was 0.12 ± 0.07 mm/year2 for 1993-2018. Regional variability tends to be lower. The linear trend, based on altimetry data, was 3.15 mm/year for the Black Sea during the same period. Simultaneously, based on coastal tide gauge data, the linear trend is much lower than 1.6÷2.2 mm/year. The contribution of freshwater balance variability is roughly the same for both types of data; the difference lies in the additional contribution of the dynamic level, which is recognized by altimetry in more extent than by tidal gauge observations. The work focuses on the impact of dynamic processes of different spatial scales on the interannual variability of the Black Sea level. The influence of mesoscale processes was treated as dynamic noise and was removed by spatial filtering of sea level data. As a result, estimates of linear trends and acceleration of trends (quadratic trend coefficient) and errors of their determination for 95% confidence interval are obtained. Comparison of annual sea level anomalies after filtration with coastal observations clarifies the interannual variability of the Black Sea level.
The runoff of Yenisei and Ob has a significant impact on the Kara Sea freshening. The paper analyzes longterm satellite data on the sea surface salinity in the Kara Sea during the ice-free period for 2015–2021 in order to identify the position and dynamics of the river plumes and the region of the freshwater influence. It was found that the area of the freshwater influence limited by the isohaline of 26 psu, is determined by the total Yenisei and Ob inflow into the Kara Sea. The interannual variability of the freshwater area in August is determined by the runoff of the Ob and Yenisei accumulated for June–August and the wind regime. Analysis of the sea surface salinity identified three types of freshwater distribution based on the analysis of salinity at the sea surface. The different types of large-scale atmospheric circulation over the Kara Sea, determined by the Arctic Oscillation index, has also been shown to affect the formation of freshwater regions. It was found that during the negative phase of the Arctic Oscillation, when the anticyclonic pressure area is over the Arctic, most part of the Kara Sea is occupied by freshwater and the position of the 26 psu isohaline is northern of 77°N. This type of freshwater propagation was observed in August 2015 and 2019. Other types of freshwater propagation are characteristic of the positive phase of the Arctic Oscillation, when a cyclonic pressure area is located on the Arctic Ocean.
The maximum rivers inflow into the northwestern part of the Black Sea is on May-June. The plume occupies the largest area during this period. The alongshore current of desalinated waters, directed to the south, is formed, its transport increases. The mixing of water and its transport affect the spatiotemporal distribution of chlorophyll-"a" concentrations and, in general, the ecological state of the shelf waters. The six typical wind field distributions are obtained as a result of synoptic situations analysis by self-organizing Kohonen map method. It’s can be grouped by the predominance of the northward and southward winds. Estimates of the frequency of occurrence of synoptic situations for a decade have been obtained and their interannual variability has been analyzed in comparison with climatic indices characterizing large-scale atmospheric circulation.
The relationships of meteorological parameters (total and lower clouds, temperature and relative humidity) with variations in the flux of cosmic rays and solar activity at the South coast of Crimea are considered. The anomalies of cosmic radiation, the solar activity and the considered meteorological parameters are determined. The correlation relationships between the cosmic ray anomalies, solar radiation, cloudiness, air temperature, and air humidity are revealed. The presented data confirm the fact of a significant influence of cosmic ray anomalies and solar activity on the meteorological parameters.
The spatiotemporal variability of chlorophyll concentrations on the North-Western Shelf of the Black Sea was studied. The monthly average chlorophyll data of the CMEMS for 2007-2017 are analyzed with a spatial resolution of 1 km. As a result, a breakdown scheme for 4 regions is proposed and the cross-correlation coefficients are estimated for each pair of neighboring regions by the moving correlation method. The wind field repeatability was analyzed using the six-hour ERA-Interim reanalysis surface wind data for the periods which were identified by the maximum values of the correlation coefficients. The duration and frequency of transport of chlorophyll between regions has significant interannual variability due to the variability of the wind field on the same time-scale. The results are discussed and compared with recent achievements about the spatial variability and cross-frontal exchange of chlorophyll on the North-Western Shelf of the Black Sea.
Results of regular observations and data analysis show significant correlation between the total ozone in the atmosphere with cosmic rays and hydrometeorological parameters (air and sea water temperature, humidity, precipitation) at the Black Sea Hydrophysical Proving Ground (BSHPG) located at the Southern Coast of Crimea at synoptic, seasonal and interannual scales of temporal variability. The maximum and minimum annual, monthly, decade, and daily values of total ozone, as well as its long-term norm for South Coast of Crimea, are estimated. The comparative plots of total ozone, cosmic rays intensity and hydrometeorological parameters are analyzed and correlations between them calculated. The obtained results confirm the important role of total ozone as an intermediate link between cosmic and solar radiation fluxes and atmospheric processes governing the formation of climate and weather pattern in the contact zone of marine and continental air masses.
KEYWORDS: Climatology, Temperature metrology, Atmospheric physics, Atmospheric modeling, Climate change, Gases, Data analysis, Brain mapping, Composites, Control systems
The interannual variability of the surface air temperature (SAT) in the Arctic region, including the Barents Sea, is studied on based of use ERA-Interim re-analysis data for the period 1979-2017. The mean SAT map, root-mean-square values and coefficients of linear trend maps are constructed. The obtained estimates are compared with observational data, and with the influence of large-scale atmospheric circulation processes. The relationship between the different types of the atmospheric circulation over the region and the spatial distribution of surface air temperature on seasonal and interannual scales is analyzed. The relevance of the study is determined by the need to study the physical patterns of intensive atmospheric circulation development over the Arctic, the trends of their inter-annual variability, and the relationships with surface air temperature anomalies on the long-term scales.
It is studied the plume response, formed by the Danube River in the North-Western part of the Black Sea, to the wind forcing. Two cases are considered: the wind of the N-NE and S-SW directions. The plume evolution, alongshore flow formation and suspended matter transfer are analyzed on the base of satellite data at a wavelength of 551 nm for these two wind forcing scenarios. The coastal current dynamics and formation of Danube plume and salinity front are studied on the basis of 3D numerical model which was adapted to the conditions of the North-Western shelf. The obtained results from the satellite data analysis are compared with results of numerical simulation of plume formation under the action of wind in order to estimate the model sensitivity to variations of the wind direction and of the wind speed magnitude.
This paper uses an original approach for the typification of synoptic situations from re-analysis data over a long period of time. This approach includes the typification of surface atmospheric pressure and surface wind velocity fields over the Azov-Black Sea basin. The results of typification (structures) of surface atmospheric pressure and surface velocity are presented in the form of Kohonen self-organizing maps (SOM), and the percentage of time recurrence of the allocated structures is given. The relevance of the study is due to the need to study the physical patterns of development of various types of intense atmospheric circulation over the Azov-Black Sea basin and their relationship with the largescale atmospheric circulation on multi-annual scales.
In order to determine the influence of corpuscular solar and galactic fluxes on meteorological processes, a comparison was made of the time variation of cosmic radiation in the range of more than 3 MeV with the change in atmospheric precipitation and other atmospheric parameters for the period 2009-2017 obtained during observations at the Black Sea Hydrophysical Proving Ground (BSHPG) of Russian Academy of Sciences in Katsiveli settlement (Southern coast of Crimea). The results confirm the fact that the intensity of cosmic radiation has a significant effect on the formation of a number of hydrometeorological characteristics of the atmosphere (precipitation, air temperature, humidity, total and low clouds) at synoptic, seasonal and interannual scales of temporal variability.
The main objective of this research is to study the interannual variability of the Black Sea chlorophyll-a concentrations related to the forcing of physical factors (SST, wind, sea circulation) and/or influence of climate variability. The Self-Organization Map (SOM) analysis was applied to identify typical (recurrent) spatial patterns of chlorophyll-a concentrations and physical forcing data. The results of SOM analysis are compared with temporal variability of the climatic indices (NAO, EAWR). The propagation of desalinated water through Danube delta along the Western Black Sea coast and the hydrological structure of shelf water are studied. The dynamics, the coastal current, and formation of Danube plume and salinity front are studied on the basis of numerical modeling which was adapted to the conditions of the North-Western shelf. The results of numerical modeling of effects of plume and buoyancy current evolution, shelf water stratification and wind forcing for summer period conditions are discussed. As a result, the model gives qualitatively correct position of salinity front related with Danube discharge, plume and alongshore current evolution.
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