1,721,047 research outputs found
Cold core eddies and fronts of the Antarctic Circumpolar Current south of New Zealand from in situ and satellite data
No full textMesoscale variability of the carbonate system in the Ross Sea (Antarctica) during the 2014 summer season
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Position of main ACC fronts south of New Zealand from satellite altimetry and XBT data in the period 1994-2015
No full textA long time series of XBT data collected during Austral summers and satellite altimetry data south of New Zealand
are used to identify the positions of the main Antarctic Circumpolar Current (ACC) fronts and their branches from 1994
to 2015. The study area has been investigated since 1994 in the framework of the Climatic Long-term Interaction for the
Mass balance in Antarctica (CLIMA), the Southern Ocean Chokepoints Italian Contribution (SOChIC) and the Marine
Observatory in the Ross Sea (MORSEA) projects of the Italian National Research Program in Antarctica (PNRA). During
these projects, in situ temperature sections of the surface layer (0-800 m) of the Southern Ocean along the track New
Zealand-Ross Sea have been occupied almost every summer season by means of XBT.
The flow of the ACC is well known to be concentrated in several jets associated with fronts, or regions of strong
horizontal gradients in water mass properties and sea surface height. These fronts are linked to particular water mass
features, allowing simple criteria based on temperature and salinity to be used to locate them. In this study regional
thermal criteria have been used for the detection of ACC fronts from in situ XBT data. The positions of ACC fronts from
in situ XBT data agree with existing literature even if a slight increase in the standard deviation during last years is found
and the indication of a southward trend in the positions of fronts is shown.
Moreover, satellite altimetry data provided by AVISO have been used to identify the positions of the fronts on the
basis of specific dynamic height values usually associated to each front as well as through the location on the maximum
Absolute Dynamic Topography gradient within a predetermined frontal region. Both altimetry-based methods allowed us
to partially fill the gap between consecutive in situ measurements and offered different results. These positions have been
compared with those determined from in situ data and finally results from the three identification methods are discussed
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Surface Heat Budgets in the Ross and Weddell Seas and their relationship to Global Climate
No full textQuasi synoptical detection of the ACC fronts south of Africa and New Zealand from in situ data
No full textExistence and inter-decadal changes of the Antarctic Circumpolar Wave during last 142 years and its relationship to large scale modes of variability
No full textXXXIV SCAR meeting - Position of main ACC fronts south of New Zealand from satellite altimetry and XBT data in the period 1994- 2015
No full textRelationship between surface heat budgets in the Ross and Weddell Seas and global climate variability
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