Campbell Scientific CS725 Snow Water Equivalency Sensor - Manual (Page 22)

CS725 Snow Water Equivalency Sensor
Once the soil is frozen, this quantity is relatively constant. The
format is an integer between 1 and 150.
[10] Estimated soil humidity in % weight (min: 1, max: 150) for
HCalib mode
This is a site-specific parameter used for the auto calibration of the
CS725. The auto calibration mechanism calculates baseline values
for the coefficients n0Ke and n0Tl. These coefficients correspond to
the integrated rates of gamma rays seen by the detector for the K peak
(n0Ke) and the Tl peak (n0Tl) with zero moisture. The HCalib
parameter is normally the humidity measured by some other means at
the time of the calibration in order to account for this humidity in the
soil when the parameters n0Ke and n0Tl are evaluated. The format is
an integer.
[11] N0K
This site specific parameter is used in the calculation of the SWE. It
represents the integrated gamma ray count rate for the potassium
40 K
isotope peak, with no snow cover and dry soil. This number is, of
course, dependent upon the level of natural radio-activity of the soil
at the installation site. It can only be calculated on the site. The auto-
calibration method is a tool to obtain the first estimate of that
parameter . The format is an integer.
[12] N00K (residual K counting) Default: 0
This is a parameter to account for the gamma rays coming from
above the surface of the snow. This is typically a very small number
(less than 225), and affects the SWE evaluation only under very high
SWE conditions (above 300 mm). This value is normally obtained
after a full season of operation and can only be determined by
comparing the CS725 data with manual measurements.
This value should not be altered above 225 unless extensive site
data analysis has been completed and Campbell Scientific has
been consulted. NOTE
[13] N0Tl
This site-specific parameter is used in the calculation of SWE. It
represents the integrated gamma ray count rate for the thallium
208 Tl
isotope peak, with no snow cover and dry soil. This number is, of
course, dependent upon the level of natural radio-activity of the soil
at the installation site. It can only be calculated on the site. The auto-
calibration method is a tool to obtain the first estimate of that
parameter. The format is an integer.
[14] N00Tl ( residual Tl counting)
This is a parameter to account for the gamma rays coming from
above the surface of the snow. It affects the SWE evaluation only
under high SWE conditions (above 300 mm). This value is normally
determined after the first year of operation. The value is typically
1900 or less.
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