The hydrography and circulation of the upper 1200 meters in the tropical North Atlantic during 1982-91

We assemble a collection of 7591 conductivity-temperature-depth stations in the tropical Atlantic between 5S and 20N for the period 1982–1991 using data from the Soviet SECTIONS program enhanced by contributions primarily from the WESTRAX and FOCAL/SEQUAL programs. Most of the stations are west of 30W, forming a series of 21 surveys. In addition there were five multi-ship basinwide surveys, each taking 1.5–3 months to complete. The quality of the SECTIONS data is discussed and comparisons between the data sets are shown. Within the pycnocline, southern water is distinguished by salinity that is 0.3 psu lower than its northern counterpart at the same density. This difference allows us to distinguish the origin of pycnocline water. Based on this information together with geostrophic analysis we confirm that much of the water transported across the equator in the North Brazil Current retroflects eastward south of 8N. In summer and fall the water of the North Brazil Current merges with the water of the North Equatorial Current to form the North Equatorial Countercurrent, whose axis shifts southward with depth. East of 35W part of the mass transport in the Countercurrent is lost to the equatorial zone, while the rest continues eastward. During winter and spring eastward currents are found in two latitude bands, a surface current between 5–10N and a weaker current south of 5N confined to the thermocline. This latter North Equatorial Undercurrent has no surface expression in winter. During the summer and fall the northern boundary of Southern Hemisphere water at pycnocline depths is given by the North Equatorial Countercurrent. During the rest of the year the northern boundary of Southern Hemisphere water only penetrates to the edge of the weaker North Equatorial Undercurrent south of 5N. The availability of ten years of data allows us to examine aspects of year-to-year variability. Among these results the data set reveals strong meandering of the North Equatorial Countercurrent between 42W and 35W during the summer of 1987. The meandering also appears in contemporaneous Geosat altimetry. Another unusual feature occurred in the summer 1986 when there was a strong thermocline current transporting water northward at the rate of 26 Sv. Water mass analysis shows that this current was the result of a pressure gradient set up by an intrusion of warm low-salinity water from the Southern Hemisphere. The fact that this high transport occurred in the interior ocean suggests that interior flows must be monitored during any attempt to observe meridional transports of mass or heat

Interannual to Decadal Variability of Atlantic Water in the Nordic and Adjacent Seas

Warm salty Atlantic Water is the main source water for the Arctic Ocean and thus plays an important role in the mass and heat budget of the Arctic. This study explores interannual to decadal variability of Atlantic Water properties in the Nordic Seas area where Atlantic Water enters the Arctic, based on a reexamination of the historical hydrographic record for the years 1950-2009, obtained by combining multiple data sets. The analysis shows a succession of four multi-year warm events where temperature anomalies at 100m depth exceed 0.4oC, and three cold events. Three of the four warm events lasted 3-4 years, while the fourth began in 1999 and persists at least through 2009. This most recent warm event is anomalous in other ways as well, being the strongest, having the broadest geographic extent, being surface-intensified, and occurring under exceptional meteorological conditions. Three of the four warm events were accompanied by elevated salinities consistent with enhanced ocean transport into the Nordic Seas, with the exception of the event spanning July 1989-July 1993. Of the three cold events, two lasted for four years, while the third lasted for nearly 14 years. Two of the three cold events are associated with reduced salinities, but the cold event of the 1960s had elevated salinities. The relationship of these events to meteorological conditions is examined. The results show that local surface heat flux variations act in some cases to reinforce the anomalies, but are too weak to be the sole cause

The Ocean Reanalysis Intercomparison project (ORA-IP)

Uncertainty in ocean analysis methods and deficiencies in the observing system are major obstacles for the reliable reconstruction of the past ocean climate. The variety of existing ocean reanalyses is exploited in a multi-reanalysis ensemble to improve the ocean state estimation and to gauge uncertainty levels. The ensemble-based analysis of signal-to-noise ratio allows the identification of ocean characteristics for which the estimation is robust (such as tropical mixed-layer-depth, upper ocean heat content), and where large uncertainty exists (deep ocean, Southern Ocean, sea ice thickness, salinity), providing guidance for future enhancement of the observing and data assimilation systems

The Ocean Reanalyses Intercom parison Project (ORA - IP)

Uncertainty in ocean analysis methods and deficiencies in the observing system are major obstacles for the reliable reconstruction of the past ocean climate. The variety of existing ocean reanalyses is exploited in a multi-reanalysis ensemble to improve the ocean state estimation and to gauge uncertainty levels. The ensemble-based analysis of signal-to-noise ratio allows the identification of ocean characteristics for which the estimation is robust (such as tropical mixed-layer-depth,upper ocean heat content), and where large uncertainty exists (deep ocean, Southern Ocean, sea-ice thickness, salinity), providing guidance for future enhancement of the observing and data assimilation systems

An assessment of upper ocean salinity content from the ocean reanalyses inter-comparison project (ORA-IP)

Many institutions worldwide have developed ocean reanalyses systems (ORAs) utilizing a variety of ocean models and assimilation techniques. However, the quality of salinity reanalyses arising from the various ORAs has not yet been comprehensively assessed. In this study, we assess the upper ocean salinity content (depth-averaged over 0–700 m) from 14 ORAs and 3 objective ocean analysis systems (OOAs) as part of the Ocean Reanalyses Intercomparison Project. Our results show that the best agreement between estimates of salinity from different ORAs is obtained in the tropical Pacific, likely due to relatively abundant atmospheric and oceanic observations in this region. The largest disagreement in salinity reanalyses is in the Southern Ocean along the Antarctic circumpolar current as a consequence of the sparseness of both atmospheric and oceanic observations in this region. The West Pacific warm pool is the largest region where the signal to noise ratio of reanalysed salinity anomalies is >1. Therefore, the current salinity reanalyses in the tropical Pacific Ocean may be more reliable than those in the Southern Ocean and regions along the western boundary currents. Moreover, we found that the assimilation of salinity in ocean regions with relatively strong ocean fronts is still a common problem as seen in most ORAs. The impact of the Argo data on the salinity reanalyses is visible, especially within the upper 500m, where the interannual variability is large. The increasing trend in global-averaged salinity anomalies can only be found within the top 0–300m layer, but with quite large diversity among different ORAs. Beneath the 300m depth, the global-averaged salinity anomalies from most ORAs switch their trends from a slightly growing trend before 2002 to a decreasing trend after 2002. The rapid switch in the trend is most likely an artefact of the dramatic change in the observing system due to the implementation of Argo

Operational features of batteries used in aviation equipment

The basic characteristics of aviation batteries both acid and alkaline are described. Their operational features are considered

On Solving Statistical Problems for the Stochastic Processes by the Sufficient Empirical Averaging Method

A problem of the statistical estimation of stochastic process functionals is considered. The sufficient empirical averaging method is used. The method requires the existence of the complete sufficient statistics for unknown parameters. Some examples are considered

QUALIFICATIONS FRAMEWORK DEVELOPMENT AND QUALIFICATIONS RATING IN THE LAND MANAGEMENT SPHERE

The aim of the research is to observe the existing approaches to qualifications framework development in the sphere of land management, cadastres and real estate management, as well as the qualifications framework adaptation to European system. The relevance of the issue is related to the specific professional and institutional problems facing Russian educational establishments engaged in personnel training in the given sphere. The authors demonstrate the qualifications framework development in the land management sector regarding it as a key mechanism of educational mobility and the router for knowledge acquisition and updates. The qualifications framework is referred to as a systematic and structured description of recognized qualifications. The accepted worldwide methodology of organizing the educational process and quality control system is given. The emphasis is on the need to comply the qualifications framework with the Russian State Educational Standards