Vol 56, No 3 (2016)

A new algorithm for cloud cover estimation has been formulated and developed based on the synthetic control index, called the grayness rate index, and an additional algorithm step of adaptive filtering of the Mie scattering contribution. A setup for automated cloud cover estimation has been designed, assembled, and tested under field conditions. The results shows a significant advantage of the new algorithm over currently commonly used procedures.

Winter convection in the Irminger Sea leading to the formation of Labrador Sea Water (LSW) is analyzed using CTD data collected along the 59.5° N transatlantic section in 2004–2014, winter Argo data from 2012–2014, and daily North American regional reanalysis (NARR). The interannual variability of LSW in the Irminger Sea is investigated. The dissolved oxygen saturation rate of 93% is used to indicate maximal local convection depth. It is shown that the deepest convection (up to 1000 m) resulting in the largest LSW volume that formed in the Irminger Sea in 2008 and 2012. These years were characterized by numerous storms with anomalously strong turbulent heat loss from the ocean to the atmosphere and negative air temperature to the east of the southern tip of Greenland in January–March. LSW became warmer by 0.42°C, saltier by more than 0.03 PSU, and more oxygenated by 8 µmol/kg between 2004 and 2014. A strong LSW decay in the Iceland Basin is also noted.

The paper presents results of analyzing the data on the variability of salinity in the upper layer of the coastal zone (including the seasonal thermocline) of the Black Sea during the 2010–2013 warm seasons (April–November). The data for the analysis were obtained from the regularly conducted CTD probing the by R/V Ashamba on a cross section abeam the Golubaya Bay (Gelendzhik). The relationship between salinity anomalies, coastal precipitation, and wind forcing is analyzed. It is shown that the contribution of thermal stratification to the density stratification in the seasonal thermocline is almost always greater than the contribution of salinity stratification, and the ratio of the former to the latter increases from April to November.

Background concentrations of Fe, Mn, Cu, Zn, Pb, Cd, and Ni were calculated for thalli of abundant algae of Fucus, Silvetia, Sargassum, Cystoseira spp. from the northwest Sea of Japan during 1987–2008. As the upper threshold levels of metal background concentrations, the median values plus double medians of absolute deviations from the medians were used (Me + 2MAD). The lower threshold level of the background concentration equal to the physiological need for an element is the median of 15% minimum values in the sampling minus the double median of absolute deviations from the median (Me₁₅–2MAD₁₅). The range of Me₁₅ ± 2MAD₁₅ is considered the natural background range of concentrations.

The species composition and biomass of phytoplankton, concentrations of chlorophyll a (Chl a) and nutrients, and accompanying hydrophysical conditions have been studied in the White Sea on July 6–11, 2009. The temperature of the surface water layer was lower than the multiyear average in July. Dinoflagellates dominated in the entire studied area; this was not the typical event for July. We suggest that domination of dinoflagellates was caused by low water temperature, when the nutrient regeneration rate was insufficient to support diatom growth. The abundance of microalgae and the structure of the phytoplankton community depended on the water structure. Variations in the phytoplankton community structure were caused not by substitution of specific species but rather by variability of the abundance of a single species, Heterocapsa triquetra. The highest phytoplankton biomass has been recorded in weakly stratified waters, where tidal mixing supplied the income of inorganic nutrients. The income of nutrients to the photic layer was limited in the stratified waters of Dvina Bay during the summer low-water period, so the phytoplankton abundance was low. We suggest that the lens of surface desalinated water presumably originated from the outlet of the Dvina River was registered in the central part of the White Sea.

In the Russian sector of the northern and middle Caspian Sea, 36 species of macroalgae have been identified. The green and red algae from the mesosaprobic group are dominant. An increase in the number of green algae species is revealed. The distribution of macroalgae is inhomogeneous. It is confined to the solid substrate and epiphyton. The biomass of seaweeds reaches 1.5 kg/m². Climate change has little influence on the appearance of new species in the northern Caspian Sea, but new invaders can appear in the Middle and Southern Caspian. The distribution of aquatic and coastal hygrophytic vegetation shows considerable spatial dynamics due to fluctuations in the level and salinity of the Caspian Sea. The biomass of aquatic vegetation varies in a wide range from 0.5 to 10.0 kg/m₂. Spatially detailed mathematical models adequately reflect the changes in key species of aquatic plants in space and time. It is shown that expansion of the zone of the seagrass Zostera noltii to shallow water areas is occurring at present, as well as shrinkage of the range of the dominant littoral aquatic plant Phragmites australis.

The REE contents (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) are determined by atomic emission spectroscopy in the subcolloidal fraction of bottom sediments in the Razdol’naya River–Amur Bay section. The mean contents of lanthanides in soils and river bottom sediments (before the mixing zone) are calculated. The increase in REE content and the fractioning in the series from light to middle and heavy REE in sediments of different estuary zones (river, water mixing, and marine), with the latter related to flocculation, sorption on iron and manganese hydroxides, clay minerals (hydromica, smectites), and lifetime accumulation of marine plankton, are dtermined. Via extraction of 0.5 N sodium hydroxide solution, the content of lanthanides associated with humic substances of subcolloidal fraction from the Amur Bay sediments are determined: 1.3 to 8.2% of La; 1.1 to 11% of Ce; and 0.3 to 1.5 of Gd.

The VDM (virtual dipole moment) is one of the most significant characteristics describing the behavior of the time evolution of the terrestrial magnetic field. However, we have revealed that the formulas with which VDM calculations are performed often do not coincide with each other in various literature sources. Hence, results are obtained from these calculations that cannot be identical. Their correctness is verified by comparing the dimension and obtained results with the known value of the VDM for our time.

The spatial variability of chlorophyll a concentrations was studied from the data of two near-shore expeditions and the cruise of the R/V Akademik M.A. Lavrent’ev in October–November 2010 over the northwestern part of the Sea of Japan. The sections across eddies showed a maximum of chlorophyll a at a depth of 40 m. According to the data from the cruise, the chlorophyll a concentration was maximum in the north of the sea and decreased to the south. In parallel, the procedures for chlorophyll a determination were compared for spectrophotometry with a fluorescence probe and a fluorescence flow system. The probe data of chlorophyll a fluorescence showed a high correlation with the chlorophyll a concentrations by spectrophotometry. On the contrary, data on chlorophyll a concentrations from spectrophotometry did not agree with those from the flow system. It was shown that a fluorimeter in the flow system recorded dissolved organic matter along with the chlorophyll a fluorescence.