Description: | DQR No: Platform: sgpmwrlos, sgp5mwravg,
sgpqmemwrlos
Subject: Loss of thermal stabilization
Date Submitted:
Submitted By: JIM LILJEGREN _X_ Instrument Mentor
___ EST Member
___ Science Team Member
___ Other _____________________________
For questions or problems, please contact the ARM Experiment Center at
509-375-6898 or via email at dqr@arm.gov.
Platform/Measurement:
What level data: a0,a1,c1
What location was the data collected at: SGP B1 (Hillsboro, KS)
SGP B4 (Vici, OK)
SGP B5 (Morris, OK)
SGP B6 (Purcell, OK)
SGP C1 (Lamont, OK)
Period of time in question (see table below)
Data should be labeled:
___ questionable ___ All data fields affected
_X_ incorrect _X_ Only some data fields affected:
___ wrong calibration
___ others "23tbsky","31tbsky","vap","liq"
Discussion of Problem:
I pointed out in a previous DQR (P960405.1) that during August of 1994
and 1995 the microwave radiometers would lose thermal stabilization on
very hot, sunny days when the temperature in the radiometer enclosure
rose above the set point for thermal stabilization (~50 deg C). Although
I had planned to travel to the SGP prior to August 1996 to adjust the
set points upward to prevent this problem from occuring this year, the
temperatures in July 1996 were hotter than in previous years and the
loss of stabilization problem occurred before I could make the needed
adjustment.
The purpose of this note is the identify the time periods for which
this problem occurred. More specific information about the problem,
including how the problem is detected and its effect on the reported
values of integrated water vapor and integrated cloud liquid water are
provided in the earlier DQR.
It is useful to repeat here that when the thermal stabilization is
lost, the reported precipitable water vapor increases and the liquid
water path decreases (and becomes SIGNIFICANTLY NEGATIVE (-0.1 mm) on
clear sky days). The RMS noise level in the data also increases
sharply. THESE ANOMALOUS VALUES HAVE BEEN INCLUDED IN THE 5-MINUTE
AVERAGES.
LOCATION BEGINNING DATE AND TIME ENDING DATE AND TIME
C1 (Central Facility)
1 July 96 18:25 GMT 2 July 96 02:00 GMT
2 16:45 3 02:30
3 17:40 4 02:15
4 15:50 4 17:10
5 17:00 6 03:30
6 16:00 7 03:00
7 20:20 8 01:30
18 20:00 18 23:45
19 18:30 20 01:20
20 19:45 21 02:25
21 17:00 22 02:20
22 19:30 23 23:00
B1 (Hillsboro, KS)
1 July 96 20:30 2 July 96 01:15
2 17:00 3 02:00
17 20:30 18 00:15
18 19:25 19 02:00
19 19:00 20 02:30
20 18:35 21 00:30
21 20:20 22 01:40
28 20:55 28 00:15
B4 (Vici, OK) 2 July 96 19:25 2 July 96 23:15
3 19:35 3 21:15
4 20:40 5 00:30
5 19:15 6 02:00
6 19:00 6 22:40
7 20:45 8 00:30
21 19:45 22 02:00
B5 (Morris, OK)
1 July 96 18:35 2 July 96 00:45
2 17:20 3 01:15
3 17:25 4 02:00
5 20:20 6 01:45
6 16:45 7 02:30
7 18:10 8 01:00
19 20:00 20 00:20
20 19:30 21 00:55
21 18:15 22 01:30
22 19:30 23 01:15
23 22:00 24 00:15
B6 (Purcell, OK)
1 July 96 20:15 2 July 96 00:10
2 18:40 3 00:05
3 20:40 4 00:35
4 20:15 5 00:10
5 19:45 6 01:15
6 19:10 7 01:40
19 21:30 19 23:00
20 20:15 21 00:05
21 21:45 22 01:00
22 21:45 23 00:00
Other observations/measurements impacted by this problem:
none
Suggested Corrections of the Problem: (e.g. change calibration factor and
recompute, flag data with this comment, etc.)
Flag with this comment. |