- 322: Soil, Site all, Wed 09-Oct-2002 08:26:25 MDT, Trime soil moisture sensor calibration
The Trime manual TDR soil moisture sensor was re-calibrated by the
manufacturer. The pre-calibration numbers showed the instrument was
well within needed specs.
reference pre-cal
2.8% 3.0%
44.2% 44%
- 320: Soil, Site all, Thu 19-Sep-2002 16:30:30 MDT, CS615 in-situ calibrations
I have calculated a linear fit for the Trime volumetric water content
data (Qsoil, % volumetric water content) versus CS615 output period
(Qtsoil, msec) for each site, Qsoil = a + b*Qtsoil. The Trime data
were collected manually during periodic site visits. The data used for
the fits also include CS615 data collected in the laboratory, both
before and after the field project, with the CS615 inserted into a
container of glass beads. The total number of data points in each fit
ranges from 5 to 7.
Note that the response of the CS615 at site 1, s/n 001, appears to
have shifted significantly around 19:40 CDT 6/20/02 and a different
calibration (1b) is used for data after that time.
In the following table, rms is the root-mean-square of the residuals
of the linear fit (% volumetric water content)
Site S/N a b rms
1a 001 -30.87 39.93 2.9
1b 001 -22.10 22.76 0*
2 005 -40.48 54.74 2.4
3 011 -37.00 51.18 1.1
4 009 -42.18 54.27 2.4
5 012 -50.22 60.33 2.3
6 008 -43.52 59.94 2.5
7 010 -30.94 39.48 1.4
8 006 -42.31 55.55 3.6
9 009 -28.03 37.08 2.4
*only two data points
- 217: Soil, Site , Fri 07-Jun-2002 22:06:56 CDT, Summary of soil profile noise
Since this project began, we have struggled with noise on the soil profile data,
especially in the water potential data. After several tests, it was found that
two changes reduce the noise significantly (at least an order of magnitude):
1. At the sites with 4-component radiation sensors (s1,8,9), the fans used to
aspirate these sensors were generating continuous noise. We disconnected
all power to all of these fans. [The primary reason for these fans is
to make the pyrgeometer dome temperature uniform, but with good natural
aspiration (wind > 2 m/s?) or uniform radiation (clear, cloudy, or night),
this isn't necessary. There could be some error at dawn or dusk.]
Sites 2-7 don't have fans anyway.
THIS HAS BEEN DONE TO ALL OF THE SITES - 1,8,9
2. At the solar-powered sites, there was daytime noise which appeared to be
related to the solar charging of the batteries. The solution we have
adopted is to run the data logger on a separate battery. These sites then
have two batteries connected to solar panels to operate the rest of the
station. Since the power consumption of the logger is quite small, we
expect the separate battery to be adequate for the rest of the project. It
also is possible that batteries could be swapped during station service
visits.
This has been done to sites 2,3,4,5,6. We still need to convert sites 7,9.
- 138: Soil, Site 9, Sun 26-May-2002 08:49:53 CDT, Repaired cable in profile 9
Did a solder & tape repair of the broken cable in profile 9 at site 9,
May 25, 19:30 - 20:00 CDT. I haven't mastered soldering while kneeling
in the mud - so don't expect a beautiful repair.
This is the cable that was apparently broken by an inquisitive cow
before the electric fence was installed. There are several cables
exposed, about 5 feet from the electronics box for profile 9. The only
obvious damage there was a broken black 3 wire cable with
black, red, and shield conductors.
Had to splice in a 1 inch piece of wire on the red conductor.
From the data, it appears that this cable is the ECH2O probe at level 1,
Qsp.l1.p9, since that signal jumps into better agreement with
the others at 20:00 CDT.
- 86: Soil, Site 8, Thu 16-May-2002 14:15:22 MDT, Checked Soil profile connections at 8
We checked the connections from the CONXALL connector inside the
logger and soil profile multiplexer boxes.
Multiplexer: all connections from CONXALL were OK.
Measured less than 1mV between ground and AG.
Logger: looked OK. Saw 11.5 V at power connector. Is this sufficient?
Also measured < 1mV between ground and AG.
- 78: Soil, Site 9, Thu 16-May-2002 10:32:59 CDT, Checked Soil profile connections
Per Steve Semmer's suggestion, checked soil profile connections in the
logger and AM16/32 multiplexers at site 9.
We checked the connections from the CONXALL connector inside the
logger and profile multiplexes boxes.. Steve wants to make sure
the power ground (pin 3 on CONXALL) and AG (analog ground?, pin 4)
were separate connections.
Profile #8: all connections from CONXALL were OK.
Banana plug connector for H2O #4 was disconnected - they come apart
easily.
Measured 9mV between ground and AG.
Profile #9: CONXALL connections OK. 9mV between grounds.
Profile #13: CONXALL connections OK. 9mV between grounds.
Reconnected banana plug connection for H2O #5.
Logger: likewise ok. 9mV between ground and AGs.
- 60: Soil, Site 2, Mon 13-May-2002 15:03:22 CDT, Trime readings at site 2
Trime: took 4 readings at site 2
%vol TDR
23.2 24
9.3 53 loose contact of trime in soil - easy to slide in/out
18.3 48
13.1 35
- 55: Soil, Site 8, Sun 12-May-2002 15:43:17 CDT, Added earth ground to soil profile multiplexer
Steve added an earth ground to the soil profile multiplexer in an
attempt to eliminate apparent noise on the data. After returning to
the base, this appears to have clobbered the data!
- 50: Soil, Site all, Sat 11-May-2002 18:28:57 CDT, Daily Status, May 11, for soil profiles
Daily Status, Saturday, May 11
Addendum as of 2210 GMT, 1710 CDT.
Fixed wind direction at site 6 and pyg.in, pyg.out at site 5.
Soil Profiles
-------------
Tsoil Some profiles missing at site 1 after rain;
all levels noisy at site 8
Qsoil High at site 1 after 2200 May 10
Qsoil1 noisy at site 3 after 1400 May 9
Qsoil1,4,5 < 0 at site 9; Qsoil6 < 0 at site 1
WPtemp some profiles missing at site 1 after rain;
all levels noisy at site 8
WPdiff WPdiff < 0 at site 1 after rain; also frequenty at site 9
all levels noisy at site 8