FATE OF MERCURY IN THE ARCTIC Michael Evan ... - COGCI

Fate of Mercury in the Arctic 42
vertical wind velocity, needed to calculate the REA flux, see later, and the value beta,
also needed to calculate the vertical flux and the number of times each valve was
switched in during the run. The data could only be retrieved by stopping the system, so
data was seen only first after the sampling period. The text output file was not
comparable with the file saved for each individual run, the .ACU extension files. In the
text output file, the total number of counts did not add up to the total run time, and the
value for the standard deviation of the vertical wind velocity and sometimes, beta, was
different for the run than the value found in the .ACU file. Therefore, the .ACU values
were used for consistency throughout analysis, since the counts in the .ACU file
equalled the total run time. The data from the .ACU file for each run was imported by
hand-typing into a spreadsheet where it was averaged for the entire sampling period and
total sampling time for each denuder calculated by multiplying the switching time by the
sampling frequency. The software allows adjustment of the sampling frequency and for
the third channel, known as the MID channel to either remain open for constant, co-
located sampling, or to open recording the air in the dead band, such that the sum of the
three channels should equal concentrations contained from a separate constant sampling
system, allowing some aspect of quality control, and employed for this study. The
computer time was not internally changed for this study, but left at its original setting, 4
hours ahead of Barrow, i.e., a run name with a start time noted as 20:00 was started at
16:00 local time.
4. A REA valve box, METSUPPORT model 1006-01, serial no. 10013, built to interface
with the sampling front end with fast response valves, that are meant to run with 5 m
long cables between the valve box and the switches, so that they might be mounted as
close to the outgoing end of the denuder as possible. It was thought that heat from