Skip to content. | Skip to navigation

Personal tools

 

 

 

 
     

 

 

 

 

 

 

 

 

 

 

 

 

You are here: Home / PDFs on demand / Bibliographical References of PDFs on demand / Quantification of errors in transmissometer-derived concentration of suspended particulate matter in the coastal zone: implications for flux determinations

C. Jago and C. Bull (2000)

Quantification of errors in transmissometer-derived concentration of suspended particulate matter in the coastal zone: implications for flux determinations

Marine Geology, 169(3):273-;286.

Optical beam transmissometers were tested at two shallow water sites off the English coast of the southern North Sea. Concentration and particle size of suspended particulate matter (SPM) or suspended sediment were measured over tidal cycles using transmissometers and laser sizer. SPM concentrations and horizontal fluxes, derived from calibrated transmissometer data, were compared with measured concentrations and fluxes, determined gravimetrically from filtered samples.SPM displayed a bimodal particle size spectrum with primary modes at 20 and 125–250μm. The first site, in the Wash embayment, was dominated by tidal resuspension with semi-diurnal addition of a coarse resuspension mode to a fine background mode. The second site, adjacent to the mouth of the Humber estuary, was dominated by tidal advection of the turbid Humber plume so that SPM concentration and quality varied diurnally as a strong lateral concentration gradient (from turbid, plume water to clear, plankton-rich shelf water) advected along the coast.Short-term variability of particle size and type diminished the correlation between optical beam attenuation and SPM concentration. Transmissometer calibration was improved by adopting a two-part correlation. At the resuspension site, the two parts were separated by onset and cessation of resuspension, one part corresponding to SPM in long-term suspension, the other to resuspended SPM. At the turbid plume site, the two parts were separated by advection of the salinity front so that one part characterised lower salinity, turbid plume water, the second part higher salinity, clear shelf water.Calculated flood and ebb SPM fluxes were inaccurate (up to 23\% error) using conventional transmissometer calibration, but error reduced to an average 3\% using two-part calibrations. There were large errors (up to 51\%) in net tidal SPM flux estimates, but these reduced to an average 16\% using two-part calibrations.

Suspended sediment, Transmissometer, Suspended particulate matter
Year

1875 1876 1877 1878 1879
1880 1881 1882 1883 1884
1885 1886 1887 1888 1889
1890 1891 1892 1893 1894
1895 1896 1897 1898 1899

1900 1901 1902 1903 1904
1905 1906 1907 1908 1909
1910 1911 1912 1913 1914
1915 1916 1917 1918 1919
1920 1921 1922 1923 1924

1925 1926 1927 1928 1929
1930 1931 1932 1933 1934
1935 1936 1937 1938 1939
1940 1941 1942 1943 1944
1945 1946 1947 1948 1949

1950 1951 1952 1953 1954
1955 1956 1957 1958 1959
1960 1961 1962 1963 1964
1965 1966 1967 1968 1969
1970 1971 1972 1973 1974

1975 1976 1977 1978 1979
1980 1981 1982 1983 1984
1985 1986 1987 1988 1989
1990 1991 1992 1993 1994
1995 1996 1997 1998 1999

2000 2001 2002 2003 2004
2005 2006 2007 2008 2009
2010 2011 2012 2013 2014
2015 2016 2017 2018 2019
2020 2021 2022 2023 2024

 
e-ressources

 

PDFs on demand
 

 

 

RBINS private PDFs