Narrow and broad senses on salinity scale

The narrow sense and applicable limit of Practical Salinity Scale 1978 (PSS78) and volumetric titration using silver nitrate to measure the salinity of non conservative oceanwater are discussed.The salinity obtained by electrical conductivity method and chlorinity salinity method obviously deviates from the absolute salinity( S A). The Density Salinity Scale(DSS98)proposed by the writers can be extensively used in conservative and non conservative water samples. The merits of the density salinity scale are as follows. (1)The Density Salinity Scale is only related to seawater mass and its buoyant effect, and is not influenced by the variation in seawater composition, and therefore,has high reliability,and repeatability for salinity determination. (2)The salinity values measured by the DSS98 have a conservative property.For oceanwater samples the salinity values are the same as those determined by the PSS78; for non conservative water samples(e g. samples from industrial sources),the salinity values are close to the absolute salinity values in comparison with those measured by the PSS78 and the Knudsen method. (3)For a solution with given solute mass,the solution concentration can be converted into the corresponding salinity by the Density Salinity Scale using the expansion coefficient of the solution and the calibration coefficient of the partial molar volume of the solute.

Analysis on the crystals of sea ice cores derived from Weddell Sea,Antarctica

In order to understand the sea ice types and its region of origin frozen in Weddell Sea,27 ice cores were taken from Weddell Sea,Antarctica during September and October,2006.Their crystals were analyzed,and their ice forming processes were evaluated based on the crystals.Photos of the thin sections from two whole ice cores,and from polygonal granular superimposed ice were taken as well as corresponding stratigraphy descriptions.Vertical profiles of salinity, density and grain size were also obtained.Based on ice core structural texture,the findings include that： 1） although large and smooth ice floes were selected as the investigation sites, the ice sheet at the sampling position may be formed by rafted ice,consolidated ice ridges and second-year ice which were affected by dynamic and thermodynamic processes together subsequently.Ice formed in pure thermal growth comprises minority.The polygonal granular superimposed ice from refrozen wetted dense snow is one type of the ice in Antarctica.2） Of the all 27 ice cores,the granular,mixed granular-columnar and columnar crystals in sea ice occupy 28.7%,14.4% and 55.2%,respectively.3） The pure thermal growth ice is predominant in marginal sea ice zone;the rafted ice and consolidated ice ridges,even second-year ice and polygonal granular superimposed ice from dynamic and thermal effects were found in front of Larsen A Ice Shelf;the thermal growth ice froze in the polynyas of Larsen A,and was transferred outwards.