- 273: RAD, Site , Wed 24-Nov-1999 16:54:19 MST, Calibration of 1/2 bubble
Using a tilt platform, I crudely estimate that changing the Q7 level
from having the bubble centered to having the center of the bubble on
the scribed circle (is this what is meant by "1/2 bubble"?) to be
equal to 37 minutes of arc. For field purposes, we should be able
to assume that this is 1/2 degree.
P.S. I calculate that a 1/2 degree tilt lowers the net radiation by about
0.5%:
The untilted net radiation measurement is: 2 pi R^2 sigma ( T1^4 - T2^4 ).
The area of the "wedge" exposed to the other surface from a tilted
sensor is: 4 pi R^2 (theta/360), for a tilt angle, theta, in degrees.
Thus, the tilted measurement is: 2 pi R^2 sigma ( T1^4 - T2^4) +
4 pi R^2 (theta/360) sigma ( T2^4 - T1^4 - T1^4 + T2^4 ) =
2 pi R^2 sigma ( T1^4 - T2^4 ) * [1 - 4 (theta/360) ].
For theta 37/60 degrees, [] = 1 - 0.7%.
Thus, for Rnet = 600 W/m2, the error due to observed tilts is about 4 W/m2.
- 271: RAD, Site , Wed 24-Nov-1999 16:41:09 MST, Rad maintainance summary
Summary from logbook entries:
Site 1:
4/9 2012 setup
5/8 1946 cleaned net & licor
Site 2:
4/9 1616 setup
5/8 1722 leveled net (off by 1/2 bubble)
~5/23 teardown the cows chewed on the [net] domes, but that probably
happened recently
Site 3:
4/16 1944 setup, but not correctly
4/27 2146 moved to real location
5/13 1917 cleaned & leveled net (off by 1/2 bubble)
~5/23 teardown the [net] dome was slightly dimpled
Site 4:
4/12 1813 setup
4/19 2325 mounted licor
5/5 1035 leveled net (slanted to west)
Site 5:
4/28 1821 installed
5/3 1740 cleaned licor (dusty)
5/4 2017 cleaned net (dirty)
~5/23 teardown the [net] dome was dirty and smashed down
Site 6:
4/7 1333 setup?
5/12 1711 cleaned net
Site 7:
4/18 1834 setup?
Site 8:
- 270: RAD, Site all, Fri 21-May-1999 16:47:07 MDT, Recalibration of Licors
This file was originally generated by Steve Oncley on 25 Feb''99
using calibration summary (from factory certificates in Cathy's files)
The file was modified by Tony delany 21 May 1999 to include the later
calibrations done by Don Nelson
To see how Don presented the sensitivity see below.
Sensor 1994 calib 1997 calib 1999 calib CASES97 site
7121 53.3 - 52.7 8
7122 50.8 50.4 48.8 4
7922 - 50.6 49.0 3
9024 61.7 - -
10835 66.0 65.6 62.6 6
10836 72.7 73.0 - 5 (also Tblmtn, Devel)
13331 86.9 89.7 87.3 7
26596 - 88.5 92.8 1
26597 - 86.5 89.8 2
All values in microamps/(1000 W/m2). Multiply by a resistance of 147 ohms
to get microvolts/(1000 W/m2). We usually use an amp/filter gain of 200
with this sensor.
1999 calibration data reported by Don Nelson was sensitivity in milleVolts/Wm-2
I have converted it to the same form as the previous calibration data by
dividing by 147 ohms x 1000
Sensor milleVolts/Wm-2 divided by 147 ohms x 1000 = microamps/Wm-2
7121 7.75 52.7
7122 7.18 48.8
7922 7.21 49.0
9024 - -
10835 9.20 62.6
10836 - -
13331 12.84 87.3
26596 13.64 92.8
26597 13.20 89.8
Ratio of (1997 or 1994 calib) / (1999 calib)
Sensor 1994 calib 1997 calib 1999 calib Ratio CASES97 site
7121 53.3 - 52.7 1.011 8
7122 50.8 50.4 48.8 1.033 4
7922 - 50.6 49.0 1.033 3
10835 66.0 65.6 62.6 1.048 6
13331 86.9 89.7 87.3 1.027 7
26596 - 88.5 92.8 0.954 1
26597 - 86.5 89.8 0.963 2
- 263: RAD, Site 7, Tue 24-Jun-1997 17:41:16 GMT, PAR sensors at site s7
The Photosynthetically Active Radiation, PAR, or Quantum sensors
used during CASES97 were deployed only at the Super-Site, s7.
Three PAR sensors borrowed from NOAA were mounted on the dark
horse at s7. One was used to monitor incoming PAR,one was used to measure
outgoing PAR, and one was kept as a spare
All sites, including s7in had Licor solar incoming radiation
sensors, soldn, and it is intended to define a ratio
PAR/soldn
for s7 and then to use soldn at all other sites to obtain
the respective PAR's.
The two NOAA sensors used both were connected via 604 ohm adapters:
rad.par.in
NOAA S/N Q22668, cal date 3 Sept''96
-168.4 umol/m^2/s/uA with 604 ohm adaptor
-168.4/604 = .2788 umol/m^2/s/uV
cal factor: .2788e6 umol/m^2/s/V
rad.par.out
NOAA S/N Q22666, cal date 3 Sept''96
-181.8 umol/m^2/s/uA with 604 ohm adaptor
-181.8/604 = .3010 umol/m^2/s/uV
cal factor: .3010e6 umol/m^2/s/V
spare
NOAA S/N Q22678, cal date 3 Sept''96
-169.8 umole/m^2/s/uA with 604 ohm adaptor
PS added by Gordon Maclean, June 24:
A gain of 1000 was applied to these analog channels, which caused them
to saturate the +-5V AtoD during the day. (A gain of 100 would have been
a better choice).
- 220: RAD, Site , Fri 16-May-1997 19:54:36 GMT, Tsfc Has Bad Aim At St. 6
Tsfc at station #6 seems to be pointed at both a small patch of wheat growing
on the very edge of a corn field and at the corn in the field. Probably when
the station was set up there was bare ground every where. The wheat is about
3 feet tall. Since this was noticed, it was decided not to repoint it.
- 95: RAD, Site 7, Thu 24-Apr-1997 16:28:19 GMT, Campbell loggers at 7 and 8
The loggers at 7 and 8 where changed to an output rate
of 1 sec. Recycling power will set the loggers back to a
5 sec output rate. The change was made to clean up the
cockpit displays.
- 77: RAD, Site 7, Tue 22-Apr-1997 16:04:52 GMT, vegguie removed from #7
Since Bob Grossman thinks the veggiemeter should be at the grassland site
(#8), I have just removed it from #7. I'll reconfigure "ops1" now.
- 54: RAD, Site 7, Sat 19-Apr-1997 19:33:06 GMT, PAR sensors
Photosynthetically-Active Radiation
There are two PAR sensors at site 7, mounted on the cross beam of the
radiation stand. They are on the upper and lower surfaces of a set of plates.
Sensor Serial# Cal date Multiplier Units
par.in Q22668 03 Sept''96 -168.4 umol. s-1. m-2 / uA
par.out Q22666 03 Sept''96 -181.8 umol. s-1. m-2 / uA
The wheat rows do not run North-South but rather about 20 degrees to the west
of South
- 46: RAD, Site 7, Fri 18-Apr-1997 18:34:35 GMT, Cal factors for 4-comp rad array
The cal factors for the piranometers and pyrgeometers deployed at super site
as components of the four component radiometer array.
NB The ASTER pyg.out was broken. It is replaced by another pyrgeometer with
only a single dome thermister. As the pyg.out dome is not subjected to
direct solar heating the single dome thermister is adequate.
Radiometer Serial # Date of cal Calfactor uV/Wm-2
ASTER psp.in 26214 8/92 8.57
ASTER psp.out 26226 8/92 8.63
ASTER pyg.in 29260 9/92 3.56 (3.27 after mod?)
L6 pyg.out 29137 4/92 4.05