Statistical characteristics of polar lows over the Nordic Seas based on satellite passive microwave data

Izvestiya, Atmospheric and Oceanic Physics - In this study polar lows over the Nordic Seas for the period of 1995–2008 have been detected and studied using the Special Sensor Microwave Imager...     

Spatial structure of the <Emphasis Type="Italic">M</Emphasis><Subscript>2</Subscript> tidal wave in the canadian arctic archipelago

The surface M ₂ tide in the Canadian Arctic Archipelago (CAA) is reproduced on the basis of the QUODDY-4 three-dimensional finite-element hydrodynamic model. Particular emphasis has been placed on comparing model estimates for the amplitudes and phases of tidal elevations and the parameters of ellipses (major semiaxis and eccentricity) of the barotropic tidal current velocity with observational data. We present their spatial distributions and the distributions of averaged (over a tidal cycle) values of the density, horizontal transfer, and dissipation rate of barotropic tidal energy. It is found that the CAA is a much less effective dissipator of barotropic tidal energy than the World Ocean.     

Delivery of chemical elements with atmospheric precipitations to the coastal regions of the Crimea in 2004–2008

We study the space-and-time variations of the delivery of fluxes of 26 elements (Na, K, Rb, Cs, Cu, Ag, Au, Ca, Sr, Ba, Zn, Cd, Hg, Hf, Ta, As, Sb, Cr, Se, Mo, W, Mn, Br, Fe, Co and Ni) with atmospheric precipitations to the sea surface in the regions of Sevastopol and the South Coast of Crimea. It is established A series of general regularities of the delivery of the sum of these elements and their soluble and insoluble forms. We also give the characteristics of their space-time variability.     

Spectral contributions of the components of seawater to the beam attenuation coefficient in surface waters of the Mediterranean Sea

We compute model spectra of the beam attenuation coefficient in surface waters of the Mediterranean Sea. These spectra are used to determine the contribution of the components of seawater (suspended matter, yellow substance, pigments of phytoplankton, and pure water) to the beam attenuation coefficient in different types of seawater. For the surface waters, we establish the relationship between the light scattering coefficient and the attenuation coefficient at a wavelength of 547 nm and determine the background (limiting minimum) value of the coefficient of absorption by the yellow substance in waters of the Mediterranean Sea. It is compared with the values of the same parameter for some other basins (Black Sea, Lake Baikal, Baltic Sea, and oceanic waters).     

Changes in the macrobenthic communities of the Gudauta Oyster Bank

Twenty-nine benthic invertebrate species were registered for the Gudauta Bank in the depth range of 8–32 m in 1990. The shallow-water biocenose was defined for the depths of less than 10 m, the biocenoses of Anadara inaequivalvis and A. inaequivalvis-Upogebia pusilla occupied the depths of 10–30 m; and the biocenosis of Pitar rudis was found for the depths of more than 30 m. The highest biodiversity and abundance of benthos was registered for the Anadara biocenoses, while the lowest, for the shallow-water ones. It was found that significant changes in the benthic communities took place in the forty years after the predator gastropod Rapana venosa was introduced into the Black Sea. The oysters became extinct on Gudauta Bank, and the species composition of the benthic community has been significantly depleted. Alien species of Anadara and Rapana became the most abundant by biomass, comprising more than 80% of the total biomass of the benthos. The population density of Rapana constituted 12 ind./m² and was the highest ever registered for the studied areas of the Black Sea. Insufficient nutrition preconditioned the small size of the mollusks.     

Objective analysis of the structure of three-dimensional atmospheric fronts

A computational method for diagnosing three-dimensional atmospheric fronts from temperature, wind, and geopotential fields on a three-dimensional regular grid is proposed. The criterion, which serves for the diagnosis of atmospheric fronts, is discussed. The weights of the input information about the mentioned fields are optimized based on the maximal difference between the correlation functions for (a) pairs of particles separated by the front and (b) pairs from one synoptic mass. These weights were different for different baric levels. The correlation functions and the optimization of weights were estimated on the basis of the archive of fields of the NCEP objective analysis on the half-degree latitude-longitude grid and data from aerological observations. The results of numerical experiments on the construction of atmospheric fronts are presented. Applying the described method to fields predicted for a term of up to 36 h showed that errors in the prognostic models introduce a relatively weak distortion into the geometry of atmospheric fronts.     

Evaluation of the coefficients of horizontal exchange in the Black Sea according to the data of drifter experiments

We generalize the method used for the evaluation of the coefficients of horizontal diffusion of Brownian particles to the nonstationary case, as applied to the drifter experiments. The limits of applicability of the proposed procedure are determined. The coefficients of horizontal exchange are computed with an aim to compare them with the estimates obtained earlier by using the generalized Taylor theory. The mutual agreement of these estimates is demonstrated. It is shown that the difference between the values of the zonal (0.19⋅10⁴ m²/sec) and meridional (0.11⋅10⁴ m²/sec) coefficients of exchange in the Black Sea cannot be explained by the effect of increase in the longitudinal component of pulsations of the velocity as a result of its transverse shear relative to the mean current. A conclusion is made that the processes of horizontal exchange in the Black Sea are geographically anisotropic.     

Seasonal variations in temperature,salinity and density in the southern coastal waters of the Caspian Sea

Variability in water temperature, salinity and density was investigated based on field measurements near Anzali Port, in the Southern Caspian Sea in 2008. Seasonal changes of seawater properties were mainly observed through the upper 100 m layer, while below this layer seasonal variations of the parameters were minor. Vertical structure of the temperature in the southern coastal waters of the Caspian Sea is characterized by a significant seasonal thermocline between 20–50 m depths with vertical variation in temperature about 16°C in midsummer (August). Decrease of the thermocline occurs with the general cooling of the air and sea surface water, and deepening of the mixed layer during late of autumn and winter. Seasonal averages of the salinity were estimated in a range of 12.27–12.37 PSU. The structure of thermocline and pycnocline indicated agreement between changes of temperature and density of seawater. Seasonal pycnocline was observed in position of the thermocline layer.     

Russian studies of atmospheric electricity in 2011–2014

This review contains the most significant results of Russian studies in the field of atmospheric electricity in 2011–2014. It is part of the Russian National Report on Meteorology and Atmospheric Sciences to the International Association of Meteorology and Atmospheric Sciences (IAMAS). The report was presented and approved at the XXVI General Assembly of the International Union of Geodesy and Geophysics (IUGG).¹ The review is followed by a list of the main published works on the studies of atmospheric electricity of Russian scientists in 2011–2014.     

Modeling photosynthesis and the growth of marine phytoplankton

The paper analyzes the most popular models of photosynthesis and growth of marine phytoplankton in the literature and demonstrates their limitations. A new approach to modeling is proposed and used to obtain new models of marine phytoplankton photosynthesis and growth. An important feature of the proposed models is their ability to describe coupled multisubstrate cyclical interactions typical of biochemical and physiological processes. As a first approximation, the mathematical models are represented by equations of nonrectangular hyperbolas. The models describe the stoichiometry of extraction of elements from the medium, whatever the degree of their limitation, an important feature in describing biogeochemical cycles of elements. This stoichiometry is governed by measurable internal parameters of an organism (substrate parameters) and can be a key cause of stoichiometric formation of elements in the ambient medium, described, for example, by the Redfield ratio. The substrate constants are fundamental characteristics of the models, which form “automatically” in the construction of model equations in arbitrary units.