Climate-Related Changes in the Vegetation Cover of the Taiga and Tundra of West Siberia over the Period of 1982–2015 Based on Satellite Data

Izvestiya, Atmospheric and Oceanic Physics - This paper presents the results of a trend and correlation analysis of the air temperature and the normalized difference vegetation index (NDVI)...     

Response of Landscapes of the Sikhote-Alin Western Slopes to the Middle–Late Holocene Climatic Changes

The response of landscape biotic components of the western slope of the Sikhote-Alin Mountains (Bikin River middle flow) to the Middle–Late Holocene climate changes is discussed. The paleoreconstruction object was the Krasny Yar mari, which developed under the control of multidirectional short-term climatic changes. The last millennium was marked by particularly rapid and frequent changes in the local landscapes. The closely spaced orographic barrier strongly affected the development of biotic components and changes in the swamp hydrological regime. The moisture dynamics within the river catchment considerably controlled the development and change of the peat-forming plants. Several stages of the mari development were reconstructed; each began from the accumulation of eutrophic peat. It was followed by the transitional eutrophic–mesotrophic stage, with a higher role of atmospheric supply. The larch forests appeared in this part of the valley within the Atlantic–Subboreal cooling period. Korean pine developed in the forest vegetation in the low mountain relief at the beginning of the Subboreal and became one of the leading trees ~2.6–2.3 ka BP. The lower role of the Korean pine and birch forest expansion in the first half of the Subatlantic could be related to the fires. The broadleaf–Korean pine forests became widespread in the Medieval Warm Period. Local swamp landscapes changed dramatically in the Little Ice Age, while the slope vegetation was not subject to any major changes. The landscapes were also affected by the fires, which became more frequent. The derivative communities with birch appeared on the mari. Moreover, this part of the valley was occasionally subject to heavy flooding.     

The First Results of Monitoring the Formation and Destruction of the Ice Cover in Winter 2014–2015 on Ilmen Lake according to the Measurements of Dual-Frequency Precipitation Radar

Izvestiya, Atmospheric and Oceanic Physics - The launch of the Dual-frequency Precipitation Radar (DPR) opens up new opportunities for studying and monitoring the land and inland waters. It is the...     

Russian Climate Research in 2015–2018

Izvestiya, Atmospheric and Oceanic Physics - The results of Russian studies of climate and its changes (published in 2015–2018) are presented using a review prepared for the National Report...     

Relationship between Natural Climate Variability and Equilibrium Sensitivity in the Climate Model of the Institute of Numerical Mathematics of the Russian Academy of Sciences to Increasing СО2

Izvestiya, Atmospheric and Oceanic Physics - The amplitude of natural climate variability is considered in several versions of the Institute of Numerical Mathematics, Russian Academy of Sciences...     

Spatiotemporal Spectral-Response Assessment of the Forest Cover of Small Dry Valleys in the Central Russian Forest–Steppe

Izvestiya, Atmospheric and Oceanic Physics - Results of assessment are presented for the relationship between the forest cover of small dry valleys and their spectral response through analysis of...     

Influence of Feedbacks in the Climate–Energetics System on the Intensity of an Urban Heat Island

Both horizontal and vertical heat exchanges and feedbacks between air temperature and anthropogenic heat fluxes significantly affect the characteristics of the urban heat island (UHI). The UHI intensity depends, in particular, on the ratio between the scales L_A (area of anthropogenic forcing) and L_γ (distance passed by an air particle of the oncoming stably stratified flow before its temperature approaches air temperature within the UHI). Both advection and feedback effects may be estimated based on the equation for the local heat balance of the underlying surface. In this case, heat advection is taken into account by calculating temperatures individually for the atmospheric boundary layer and the surface of the urban canopy layer. The estimates show that the asymptotics of strong advection is more characteristic of a typical city. However, under weak winds, with consideration for the feedback between air temperature and anthropogenic heat flux, some deviations from this asymptotics are probable.     

Russian Investigations in the Field of Atmospheric Radiation in 2015–2018

Izvestiya, Atmospheric and Oceanic Physics - A short survey prepared by the Russian Commission on Atmospheric Radiation contains the most significant results of works in the field of...     

Results of Russian Studies of the Middle Atmosphere in 2015–2018

Izvestiya, Atmospheric and Oceanic Physics - A review of the results of Russian studies of the middle atmosphere in 2015–2018 prepared by the Commission on the Middle Atmosphere of the...     

Changes in the population structure of Calanus sinicus during summer–autumn in the southern Yellow Sea

Calanus sinicus is a calanoid copepod widely distributed in coastal waters of China and Japan, and oversummering strategies may have major impacts on their population dynamics which in turn affect local marine food web structure. The abundance, stage composition, and sex composition of the planktonic copepod C. sinicus were studied from August to October 2002 in the southern Yellow Sea to understand how its population recovers from the over-summering state. Results showed that C. sinicus had low reproduction in August due to high temperature, except in waters near the Cheju Island with rich food and moderate bottom temperature, but the reproduction rates here decreased in September–October as food availability declined. When temperature dropped in September–October, C. sinicus actively propagated in coastal shallow waters. However, reproduction rates of C. sinicus individuals inhabiting the Yellow Sea Cold Water Mass(YSCWM) remained low during the three months of the study. The percentage of C. sinicus females was high during the reproductive period, which suggests that the sex composition of adult C. sinicus may reflect whether or not the population is in the reproductive mode.Numerous fifth copepodite stage(CV) C. sinicus aggregated in the YSCWM in a suspended developmental stage during the three months of this study, and they potentially served as the parental individuals for population development when conditions became optimal for reproduction later in the year.     

Response of Temperature Field in the Western Tropical Pacific to El Nino Events

El Nino, Anti-El Nino and normal years are defined in this paper according to time-de-pendent variations of El Nino and Southern Oscillation index. Statistics and analyses have been made of hydrological observation data related to 137°E section (34°N-l°S) from 1967 to 1983. It is shown from the results that there are obvious interannual variabilities of tempera-     

Wave Activity and Its Changes in the Troposphere and Stratosphere of the Northern Hemisphere in Winters of 1979–2016

An analysis of spectra of wave disturbances with zonal wave numbers 1 ≤ k ≤ 10 is carried out using winter (November to March) ERA-Interim reanalysis geopotential data in the troposphere and stratosphere for 1979–2016. Contributions of eastward-traveling (E), westward-traveling (W), and stationary (S) waves are estimated. The intensification of wave activity is observed in the tropical troposphere and stratosphere and in the upper stratosphere of the entire Northern Hemisphere. The intensification of wave activity in the tropics and subtropics is noted for waves of all types (E, W, and S), while in the middle and higher latitudes it is related mainly to stationary and eastward waves. Near the subtropical tropopause, the energy of stationary waves has increased in recent decades. In addition, in the tropical and subtropical troposphere and in the subtropical lower stratosphere, the energy of the eastward-traveling waves in El Niño years may be one and a half times or twice the energy in La Niña years. The spectrally weighted zonal wave numbers for waves of all types (E, W, and S) are the largest in the upper subtropical troposphere. The spectrally weighted zonal wave number for W and S waves is correlated with the Atlantic Multidecadal Oscillation index and varies by 15% in 1979–2016 (on an interdecadal time scale). The spectrally weighted wave period is larger in the stratosphere than in the troposphere. It is maximal in the middle extratropical stratosphere. The spectrally weighted wave periods correlate with the activity of sudden stratospheric warmings. The sign of this correlation depends on the latitude, atmospheric layer, and zonal wave number.     

Relationship between Anomalies of the Rate of Snow Cover Formation in Western Siberia and Atmospheric Dynamics in the Northern Hemisphere in the Autumn–Winter Season

Izvestiya, Atmospheric and Oceanic Physics - The relationship between the anomalies of the intensity of snow cover formation in Western Siberia (WS) and thermodynamic state of the atmosphere of...     

Climate Change in the Hydrometeorological Parameters of the Black and Azov Seas (1980–2020)

Oceanology - To study the nature of climate change in the hydrometeorological parameters of the Black and Azov Seas—surface air temperature (SAT), sea surface temperature (SST), ice cover,...     

Biological Research in the Siberian Arctic Seas in Summer–Autumn 2019 (Cruise of the R/V Professor Levanidov)

Oceanology - The article presents the results of hydrobiological, ichthyological, trophological, acoustic, and genetic research aboard the R/V Professor Levanidov in the Chukchi, East Siberian,...     

Response of rock-lobster populations in the Benguela ecosystem to environmental change — a hypothesis

Studies some years ago suggested that yields of Jasus lalandii in the northern Cape and Namibia had declined as a result of severe overfishing and progressive reductions of minimum size limits, especially between 1960 and 1970. Although catches were temporarily boosted to artificially high levels by reductions in minimum size, evidence is presented which suggests that sustainable yields may have declined largely as a result of environmental changes during and after the 1960s. It is postulated that a progressive expansion of oxygen-deficient shelf water may have forced lobsters to occupy a much-reduced habitat in shallow waters, where overcrowding has resulted in reduced growth and survival, and production and yields have declined accordingly. It is suggested that increased competition for food and space in the better-oxygenated shallows has led to a diminution in the size at sexual maturity of female lobsters and reduced adult growth rates. In addition, low levels of dissolved oxygen may have direct physiological effects on rates of feeding, growth and mortality. Possible reasons for the likely change in oxygen concentrations after the mid 1960s are discussed. Reduced grazing of phytoplankton by planktonic herbivores (zooplankton and clupeoid fish) as well as increased phytoplankton production per se are considered to be possible causative factors leading to the carbon-overloading prevalent in the central and northern Benguela system during the past two decades.     

An early footprint of fisheries: Changes for a demersal fish assemblage in the German Bight from 1902–1932 to 1991–2009

Groundfish survey data from the German Bight from 1902–08, 1919–23, and 1930–1932 and ICES International Bottom Trawl Survey (IBTS) quarter 3 data from 1991 to 2009 were analysed with respect to species frequencies, maximum length, trends in catch-per-unit-effort, species richness parameters (SNR) and presence of large fish (Φ₄₀), the latter defined as average presence of species per haul with specimens larger than 40 cm given. Four different periods are distinguished: (a) before 1914 with medium commercial CPUE and low landings, Φ₄₀ ≈ 2, high abundance in elasmobranchs and SNR conditions indicating highly diverse assemblages, (b) conditions immediately after 1918 with higher commercial CPUE, recovering landings, Φ₄₀ at > 4 in 1919, and SNR conditions indicating highly diverse assemblages, (c) conditions from 1920 to the early 1930's with decreasing commercial CPUE, increased landings, decreasing Φ₄₀, SNR conditions similar to later years indicating less diverse assemblages, and a decrease in elasmobranchs. In the IBTS series (d), Φ₄₀ remains low indicating an increased rarity of large specimens, and SNR characteristics are similar to the third period. Dab, whiting and grey gurnard have increased considerably in the IBTS series as compared to the historic data. Φ₄₀ is suggested an alternative indicator reflecting community functional diversity when weight based indicators cannot be applied.     

The heat balance on the sea surface in the mature phase of 1982/83 El Nino event

Using the air-sea data set of January, 1983 (the mature phase of the 1982/83 El Nino event), the net radiation on the sea surface, the fluxes of the latent and the sensible heat from ocean to the atmosphere and the net heat gain of the sea surface are calculated over the Indian and the Pacific Oceans for the domain of 35°N-35°S and 45°E-75°W. The results indicate that the upward transfer of the latent and the sensible heat fluxes over the winter hemisphere is larger than that over the summer hemisphere. The sensible heat over the tropical mid Pacific in the Southern Hemisphere is transported from the atmosphere to the ocean, though its magnitude is rather small. The latent heat flux gained by the air over the eastern Pacific is less than the mean value of the normal year. The net radiation, on which the cloud amount has considerable impact, is essentially zonally distributed. Moreover, the sea surface temperature (SST) has a very good correlation with the net radiation, the region of warm SST coinci