DQRID : D961117.14
Start DateStart TimeEnd DateEnd Time Data Quality Metric
07/01/1996201507/23/19960000Suspect
more
Subject:
Loss of thermal stabilization
DataStreams:sgp5mwravgB6.c1
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.
Suggestions: 
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Measurements:sgp5mwravgB6.c1:
  • 31tbsky
  • tbsky23_sdev
  • num_obs
  • base_time
  • tbsky31_sdev
  • time_offset
  • water_flag_fraction
  • lat
  • vap
  • alt
  • vap_sdev
  • lon
  • 23tbsky
  • liq
  • liq_sdev
more

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