Campbell Scientific CS110 Electric Field Meter - Manual (Page 26)

CS110 Electric Field Meter
utilized to autonomously measure, process and store data to aid in site
correction.
Campbell Scientific, Inc. has performed a site correction on the CS110 2 Meter
CM10 Tripod Site described in Appendix G. The collected data between the
upward-facing unit and a downward facing CS110 2 Meter CM10 Tripod Site
is illustrated in Fig 10. A best-fit line computed from the data resulted in C
site
= 0.105 ± 4%, which is valid for users at other sites who use the same site
dimensions on level terrain clear of vegetation. Dimensional details of the 2
meter standard meteorological site are described in Appendix F.
10/02/05 Site Correction of CS110 2 Meter CM10 Tripod Site
Results indicate Csite = 0.105.
y = 0.1051x - 35.664
R 2 = 0.9996
-10000
-8000
-6000
-4000
-2000
0
2000
4000
6000
8000
-80000 -60000 -40000 -20000 0 20000 40000 60000 80000
10/02/05 Site Correction of CS110 2 Meter CM10 Tripod Site
Results indicate Csite = 0.105.
Elect
ric F
ield
(
vo
lt
/met
er f
o
r U
p
ward
F
acin
g
C
S110 SN
:1022
Mparallel_plat
e = 87.6 volt
/met
er*millivolt
Electric F
iel
d (volt/meter) for Upwar
d F
acin
g
CS110 SN:1
0
22
Mparal
le
l_p
late
=
87.6 volt/meter*mill
ivolt
Uncorrected (Csite = 1) Electric Field (volt/meter) for 2 Meter Mounted CS110 on CM10
Tripod. SN: 1023 (Mparallel_Plate = 81.77 volt/meter*millivolt)
Uncorrected (Csite = 1) Electric Field (volt/meter) for 2 Meter Mounted CS110 on CM10
Tripod. SN: 1023 Mparallel_Plate = 81.77 volt/meter*millivolt
FIGURE 11. Site correction data for CS110 2 Meter CM10 Tripod Site
The user is responsible for determining if a CS110 site is representative of
the CS110 2 Meter CM10 Tripod Site, and if not, for determining the
appropriate site correction.
The atmospheric electric field at the Earth’s surface during fair weather
conditions is on the order of –100 V/m; the negative sign indicating that the
electrostatic force on a positive charge is directed downward to the Earth’s
surface [McGorman and Rust],[Rakov and Uman]. Ballpark site corrections are
sometimes computed in fair weather conditions by assuming a -100 V/m fair
weather field. The accuracy of a fair weather site correction is questionable
because local conditions may result in a fair weather field significantly different
(>100%) from –100 V/m. Also, the unknown electric field offset may be
significant when calibrating at –100 V/m. This offset can be measured by
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