- 194: LOG, Site All, Thu 24-Sep-1998 13:25:45 MDT, Reprocessing
The oasis data has been rerun with these corrections:
1. sonic data (except for NUW sonics) tilt corrected, and rotated to
geographic coordinates.
2. CSI soil moisture (Msoil.5cm.1,2,3) corrected by a quadratic fit to the
manual measurements (from Tony and SteveS)
3. Fix to Tcase.CNR1a as requested by Scott and Jerry. Recalc
of Rlw.in|out.CNR1a using Rpile and corrected Tcase.
4. NCAR prop data from Jun 17-Jun 21 21:15Z flagged as NA.
(The azimuths were entered into the props on Jun 21).
The OKMN data starts on Jun 24.
5. Units of rain corrected from "183mm/hr" to "mm/hr" in netcdf file.
- 141: RADIATION, Site All, Mon 20-Jul-1998 11:19:45 CDT, Comparison of radiometers
Inspection of the radiation record from the beginning of the program until
July 20, indicates that July 15 was a most nearly perfect day. The
24 hour period: July 14, 18:00 until July 15, 18:00 was used to compare
radiometer responses.
Before undertaking the analysis, the pyrgeometer corrections were evoked by:
dpar(robust=F)
A comparison was made between the three four components system: NCARsum, OKMNsum and CNR1asum.
For these systems the four components sw.in, sw.out, lw.in and lw.out can be
individually examined as well as algebraically added to form a summation
or "sum"
The NCARsum and the OKMNsum both use Eppley radiometers, whereas the CNR1asum
uses Kipp and Zonen radiometers.
Note that the CNR1asum is designated Rnet.CNR1a, but is, in fact, a sum
sw.in: NCAR and OKMN agree well during the day, with a maximum difference
OKMNsw.in < NCARsw.in by 20 Wm-2 at noon.
The CNR1a shows a greater difference with a maximum difference
CNR1asw.in < NCARsw.in by 60 Wm-2 at noon
At night the OKMNsw.in is set, by software, to be 0.0 Wm-2,
The NCARsw.in has an instrumentation response of - 4 to -2 Wm-2.
The CNR1asw.in also shows this instrumentation response.
For the CNR1a the value is -10 Wm-2.
These nighttime negative instruentation responses are due to a real export
of energy by the radiometers. The treatment of the OKMNsw data is probably
reasonable, but masks the problem, which also occurs during the daytime.
sw.out: In the day time the three systems differ over a range of 25 Wm-2 at
noon. As the three look down at different surfaces this can be due
to the albedo differences. Thus the OKMN albedo is greater than that
for the NCAR site because a different grass cutting method is used
for the land under the OKMN radiometer stands. There is also more
surface shading directly under the radiometers on the NCAR stand by
the CR10 box, boom and 4-component mount.
At night the OKMNsw.out is set by software to be 0.0 Wm-2.
The NCARsw.out and the CNR1asw.out show instrumentation
responses of -2 and -5 Wm-2
lw.in: The OKMNlw.in response is very similar to the NCARlw.in response, both
in the day and at night, with the exception of the 15 Wm-2 higher
value for the 3 hour period around noon. This anomoly may be due to
photodegradation of the vacuum-deposited silicon coating on the
pyrgeometer dome.
At night the CNR1alw.in shows a fairly consistant offset of
CNR1alw.in > NCARlw.in of 20 to 30 Wm-2
In the daytime CNR1alw > NCARlw increases with a maximum difference of
+60 Wm-2 at midday.
This could be due to an incomplete dome heating correction or even to
sensitivity to sw radiation.
lw.out: The response of the three radiometer to the emission of lw radiation
by the surface is simple.
OKMNlw.out < NCARlw.out by 5 Wm-2 at night,
OKMNlw.out > NCARlw.out by 5 Wm-2 by day
Similarly
CNR1alw.out > NCARlw.out by 20 Wm-2 by night
CNR1alw.out > NCARlw.out by 35 Wm-2 by day
The difference of both the OKMNlw.in and the OKMNlw.out to the NCARlw appear
to be offsets rather than proportional differences in gain.
Comparison of net radiometers and four components summations.
The ******sum parameters are generated from the algebraic addition of the
four components. The ******net parameters correspond to the output of integral
net radiometers. Note that although the K&Z four component output is designated
"Rnet.CNR1a", it is a summation product, and here is termed CNR1asum.
Six systems were investigated:
NCARsum, OKMNsum, NCARQ7, OKMNQ7, CNR1asum and NRLite.
The general agreement was good with the only significant disagreements being
the OKMNQ7 at night and the NRLite at noon. The midday anomoly of the OKMNlw
is obvious.
Responses of the sum/net systems compared to the NCARsum:
Night-time Noon
OKMNsum: +10 Wm-2 -25 Wm-2 if noon anomoly removed
NCARQ7: +10 Wm-2 -15 Wm-2
OKMNQ7: +25 Wm-2 -20 Wm-2
CNR1asum: +0 Wm-2 -30 Wm-2
NRLite: +15 Wm-2 -50 Wm-2
Responses of the sum/net systems compared to the CNR1asum:
Night-time Noon
NCARsum 0 Wm-2 +20 Wm-2
OKMNsum +10 Wm-2 -25 Wm-2
NCARQ7 +10 Wm-2 0 Wm-2
OKMNQ7 +25 Wm-2 0 Wm-2
NRLite -10Wm-2 -40 Wm-2
- 122: SONICS, Site All, Wed 15-Jul-1998 11:10:23 CDT, uw sonics up to 4.5m
The UW sonics have been moved up to 4.5m in the nominally parallel
configuration. (I had wondered why the data didn't agree better between the
UW and ATIs and then realized that the UWs had been at 1m.) Unfortunately,
it appears from a distance that the UW1 (actually UW3) array is bent!
This also would explain why the zero calibrations found that the paths were
18.8, rather than 20 cm. I noticed that the array had been skewed during
shipping, but it may have suffered even more.
I'm going back now to bring it down and try realigning it in the jig.
- 89: SONICS, Site All, Tue 07-Jul-1998 08:34:02 CDT, Sonic tilts calculated
Steve calculated the sonic tilt angles yesterday, using fun.sonic.tilt.dat.
We used three days of data beginning June 29 16:30 CDT.
Sonic offset pitch roll b1 b2 b3 lean phase
cm/s deg deg deg deg
---------------------------------------------------------------------
ATIK
4.5m -1 0.4 0.1 -0.012 0.006 -0.001 0.36 170
CSAT
4.5m 3 0.4 0.2 0.029 0.008 -0.003 0.49 157
ATIK
9m -1 -0.4 0.6 -0.015 -0.008 -0.010 0.73 54
These fits included two groups of data, one for wind from the east and
a second for wind from the south.
We applied this to two sets of data and found that the changes in u*
and were on the order of 1-2% and that the differences between
the two 4.5m sonics were less than ~1%.
- 88: RADIATION, Site All, Mon 06-Jul-1998 09:36:37 CDT, Peculiar lw.in radiometer response
There is a discrepancy between the responses of the uplooking NCAR lw radiometer
and the uplooking OKMN lw radiometer. This is well illustrared on Jul 3, a
clear, cloud-free day.
The Rlw.in plot shows an earlier and higher peak for the OKMN than for the NCAR.
Note that the Rlw.out plots show agreement between OKMN and NCAR.
The Tdome and Tcase plots showed that the OKMN were 1-2 degreeC warmer than
NCAR, but no structure which could lead, in compensation correction, or
dome/case correction to the structural difference showed in Rlw.in.Note that
the difference of 1-2 degreeC is significant.
The Rpile.in plot shows the strong feature.Several aspects were considered:
- Ventilation: the OKMN is ventilated differently than the NCAR. However
the dome and case temperatures plots do not show the strong
feature.
- Level: to account for the phase shift a tilt of ~11 degrees would be needed
- Photodegradation: the Si vacuum deposited coating inside the dome is
susceptable to uv degradation. This could allow a non-
uniform illumination of the photopile. What history
does this radiometer have?
- 74: KRYPTONS, Site All, Wed 01-Jul-1998 11:32:06 CDT, Krypton calibrations changed
The NCAR Kryptons have been using the scaled, full-range calibrations
and for the OKMN Krypton I used the clean, wet-range calibration.
I will change both to use the scaled, wet-range calibration.
Using Campbell calibrations dated 22-May-98, I changed the files
cal_files/kryton1101 and cal_files/krypton1133:
Changed NCAR s/n 1101 to Kw = -0.137, Intercept = 2663, X = 1.011
Changed NCAR s/n 1133 to Kw = -0.137, Intercept = 2431, X = 1.434
Using the Campbell calibration dated 8-97, I changed the file
OASIS98/okmn.q
Changed OKMN s/n 1090 to Kw = -0.142, Intercept = 2271, X = 1.012
Restarted covars
- 69: SONICS, Site All, Wed 01-Jul-1998 08:50:56 CDT, Sonic elevation angles
Calculated elevation angles of the wind for the period
June 29, 16:35 CDT to July 1 8:35 CDT. During this period
u ranged from -4 to +8 m/s and v from -5 to +6 m/s.
sonic atan(w/u) atan(w/v)
4.5m NCAR 0.4 deg -0.2 deg
4.5m OKMN 0.7 deg -0.5 deg
9m NCAR -0.3 deg -0.3 deg
Mean offsets in w were on the order of a few cm/s