Sequoia LISST-100X, Руководство пользователя

Страница: 70 / 144

58 LISST-100X User’s Guide
4

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 41 of the .ASC
file (column AO in Excel).

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).
5

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.
6

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.
7

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.
8
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