کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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1261833 | 1496713 | 2009 | 7 صفحه PDF | دانلود رایگان |

The conductivities and densities were measured on 331 samples collected in the South Pacific Ocean during the P18 CLIVAR (Climate Variability and Predictability) cruise. The relative densities (ρ − ρ0) were compared to those determined from the equation of state of seawater. The excess densities (Δρ = ρMeas − ρCalc) ranged from ± 0.003 kg m− 3 in surface waters to 0.015 kg m− 3 in deep waters due to additions of nutrients and carbonates. The values of Δρ were found to be a linear function of the increases of ΔNTA, ΔSi(OH)4 and ΔNO3 in the deep waters (σ = 0.002 to 0.005 kg m− 3). The best correlations of Δρ with changes in concentration of ΔSi(OH)4 are (N = 331) given byΔρ/kgm−3=−1.7·10−3+9.4·10−5ΔSi(OH)4(σ=0.0043kgm−3).Correlation of the South Pacific data with earlier measurements made in the North Pacific and Indian oceans (N = 596) are given byΔρ/(kgm−3)=−1.7·10−3+9.44·10−5ΔSi(OH)4(σ=0.0043kgm−3).The excess densities can also be accounted for by determining the change in the absolute salinity (SA) of seawater. The values of ΔS have been estimated fromΔS=50ΔNTA+68ΔSiO2+63ΔHNO3+82ΔH3PO4.The values of Δρ/kg m− 3 calculated from the estimated values of SA agreed with the measured densities with a standard error of ± 0.004 kg m− 3. Values of SA determined from density measurements also show a correlation with ΔSi(OH)4. The Indian and South Pacific values have been fitted to (σ = 0.0044)ΔS=−2.4·10−3+1.06·10−4ΔSi(OH)4.An error of ± 0.0044 g kg− 1 in SA is equivalent to and error of ± 0.003 kg m− 3 in the density (which is the precision of the density measurements).
Journal: Marine Chemistry - Volume 114, Issues 1–2, 20 April 2009, Pages 56–62