| Summary: | Progress Code: completed Statement: Breaks in dataset occur when calibrations were run on instrument (every 24-48 hours, when weather was permitting), when lamp voltage had to be adjusted, or an Argon leak was detected and fixed (instrument has to be turned off when no carrier gas connected). Breaks in the dataset are recorded in the scanned logbooks, all times are in UTC. Variability in wind direction and ship position caused exhaust smoke from ship to sometimes blow in front of sample line, causing artificial peaks in total mercury measurements. The mercury dataset is to be interpreted in coordination with wind direction data (from an anemometer attached to sample inlet or from the ships own underway data) in order to detect contamination of the sample with exhaust plume. A significant break in data collection occurred between 25/10/2012 and 28/10/2012 when the photodiode on the instrument became faulty. Lamp voltage and intensity controls were adjusted and data collection resumed with an altered lamp circuit board (the instrument was run with a fixed lamp voltage of 9.5 V). Raw data collected from 28/10/2012 is still valid. Instrument description: Gaseous elemental mercury (GEM) was measured at five minute intervals. GEM was collected and analysed on two parallel gold traps. While GEM was collected on one gold trap, the mercury on the other traps was simultaneously being thermally desorbed and detected by a cold vapour atomic fluorescence spectrometer. The Tekran was calibrated approximately every 24 - 48 hours using an internal Hg permeation source. The internal calibration source was checked prior to shipping the instrument to Australia using an external Hg source. The internal calibration source will be verified upon return of the instrument. Instrument Setup: This instrument was sampling from a weather protected inlet positioned ~3 m off the front port side of the Monkey Deck of the Aurora Australis, directly above the bridge. The 35m heated Teflon sample line end and filter is contained within the ...
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