Sequoia LISST-200X - Page 73

LISST-200X User’s Manual LISST-200X Operation Details Page 65
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• The next thing to look for is to check the
Transmission values. The transmission must be a
number between 0 and 1.
• It is physically impossible for the transmission to be
negative or larger than 1 (one).
• Tip: The transmission value is in column 56 of the
.CSV file.
• If transmission shows up as being larger than 1
(one), then your measurement is most likely taken
in very clear water and/or you have a bad zscat
measurement obtained with dirty water and/or dirty
windows.
• If your zscat measurement was obtained using dirty
water, it may be possible to redo the zscat using
clean water and re-process the data, then check to
see if the transmission values drop below 1 (one).
It is physically
impossible for the
Transmission value to
be less than 0 (zero) or
larger than 1 (one).
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• If your transmission values generally are in the
0.98-0.995 range, your measurements are taken in
very clear water.
• This means that the signal-to-noise ratio will be low,
and the data may have a lot of noise in them, but
can most likely still be used.
Transmission values
very close to 1 yields
noisy data.
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• If your transmission values are < 0.10 (or 10%), the
water is too turbid. Disregard these data.
Data with transmission
values < 10% should
be disregarded.
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• If your transmission values are > 0.995 (or 99.5%),
the water is too clear. Disregard these data.
Data with transmission
values > 99.5% should
be disregarded.
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Summarizing
• Disregard data if laser reference is 0 or very close
to 0 (laser is dead, contact Sequoia).
• Disregard data if transmission is > 0.995 (> 99.5%).
• Disregard data if transmission is < 0.10 (< 10%).
• Be wary of data collected at transmission values
between 0.98 and 0.995 – low signal-to-noise ratio.
• Be wary of data collected at transmission values
between 0.30 and 0.10 – generally decreasing data
quality as the transmission decreases below 0.30
(30%).
Quick quide for data
QC