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Regional algorithms for the estimation of chlorophyll and suspended matter concentration in the Gulf of Finland from MODIS-Aqua satellite data

Vazyulya S., Khrapko A., Kopelevich O., Burenkov V., Eremina T., Isaev A.

Oceanologia

2014

No. 56 (4)

737--756

Validation of algorithms for the retrieval of concentrations of chlorophyll (Chl) and total suspended matter (TSM) in the Gulf of Finland from satellite ocean colour data was carried out using field measurement data from summer 2012 and 2013. These data included spectral values of the remote sensing reflectance Rrs(λ), Chl and TSM concentrations. Testing of the existing algorithms (OC4v4, OC3M, and the Baltic regional algorithms developed by Polish specialists) showed that all of them overestimated Chl several times. The new regional algorithms were developed on the basis of measured values of Rrs(λ), Chl and TSM (40 stations in total). Direct comparison of Chl and TSM values, obtained from MODIS-Aqua data with the algorithms developed here, with their in situ values showed reasonable agreement. The spatial distributions of Chl and TSM concentrations were constructed from MODIS-Aqua data. Errors of the atmospheric correction were analysed.

Round-robin intercomparison of hydrophone calibration in Russia

Isaev A., Likhachev S., Platonov V.

Hydroacoustics

1999

Vol. 2

201--204

The results of an interlaboratories round-robin comparison of hydrophone calibration techniques in the frequency range 0,1 Hz - 200 kHz carried out in Russia in 1993-97 are described. Six hydrophones of two types were circulated to twelve laboratories involved in defence, education, shipbuilding, and state metrology activity. Bofh types of hydrophones were designed in All-Russian Scientific Research Institute for Physical-Technical and Radiofechnical measurements (VNIIFTRI). Each laboratory determined the open-circuit end-of-cable hydrophone sensitivity using their normal calibration methods. The agreement between all the participants was within 1 dB at frequencies 0,1 Hz -100 kHz and within 2 dB at frequencies 100 - 200 kHz.