DQR ID | Subject | Data Streams Affected |
---|---|---|
D950110.1 | Reprocess: Effect of BBSS ground check on MWR tuning functions | DsgpmwrlosB1.a0, DsgpmwrlosB1.a1, sgpmwrlosB1.a1 |
D950110.2 | SGP/MWR/C1 - Data dropouts due to serial comm problems | sgpmwrlosC1.a1, sgpmwrlosC1.b1 |
D960115.1 | Precipitable Water Vapor (PWV) values at Hillsboro | sgp5mwravgB1.c1, sgpmwrlosB1.a0, sgpmwrlosB1.a1 |
D960129.2 | SGP/MWR/B1/B5 - Calibration questionable | sgpmwrlosB1.a0, sgpmwrlosB1.a1, sgpmwrlosB5.a0, sgpmwrlosB5.a1 |
D960404.1 | SGP/MWR/B1/B4/B5 - Reprocess: Error in MWR calibration | sgpmwrlosB1.a0, sgpmwrlosB1.a1, sgpmwrlosB4.a0, sgpmwrlosB4.a1, sgpmwrlosB5.a0, sgpmwrlosB5.a1 |
D960404.2 | SGP/MWR/B1/B4/B5 - Reprocess: MWR Tuning Functions | sgpmwrlosB1.a0, sgpmwrlosB1.a1, sgpmwrlosB4.a0, sgpmwrlosB4.a1, sgpmwrlosB5.a0, sgpmwrlosB5.a1 |
D960404.3 | ||
D960405.1 | SGP/MWR/C1 - Loss of thermal stabilization | sgp1mwravgC1.c1, sgp5mwravgC1.c1, sgpmwrlosC1.a1, sgpmwrlosC1.b1 |
D961117.2 | Loss of thermal stabilization | sgpmwrlosB1.a1 |
D961120.2 | ||
D980205.2 | Manually corrected error in header files | sgpmwrlosB1.a0, sgpmwrlosB1.a1, sgpmwrlosB5.a0, sgpmwrlosB5.a1, sgpmwrtipB5.a0 |
D980915.1 | SGP/MWR/B1/B4/B6 - Instruments in calibration (tip) mode | sgpmwrlosB1.a0, sgpmwrlosB1.a1, sgpmwrlosB4.a0, sgpmwrlosB4.a1, sgpmwrlosB6.a0, sgpmwrlosB6.a1 |
D990106.1 | SGP/MWR/B1/B4/B6/C1 - software change | sgpmwrlosB1.a0, sgpmwrlosB1.a1, sgpmwrlosB4.a0, sgpmwrlosB4.a1, sgpmwrlosB6.a0, sgpmwrlosB6.a1, sgpmwrlosC1.a1, sgpmwrlosC1.b1, sgpmwrtipB1.a0, sgpmwrtipB4.a0, sgpmwrtipB6.a0 |
D990108.1 | SGP/MWR/B1 out of calibration | sgpmwrlosB1.a0, sgpmwrlosB1.a1 |
D990113.1 | SGP/MWR/B1/B4/B5/B6/C1 - software upgrade (version 3.27) | sgpmwrlosB1.a1, sgpmwrlosB4.a1, sgpmwrlosB5.a1, sgpmwrlosB6.a1, sgpmwrlosC1.a1, sgpmwrlosC1.b1, sgpmwrtipB1.a0, sgpmwrtipB4.a0, sgpmwrtipB5.a0, sgpmwrtipB6.a0 |
D990916.1 | SGP/MWR/B1/B4/B5/B6 - data file split at 23:59 | sgpmwrlosB1.a1, sgpmwrlosB1.b1, sgpmwrlosB4.a1, sgpmwrlosB4.b1, sgpmwrlosB5.a1, sgpmwrlosB5.b1, sgpmwrlosB6.a1, sgpmwrlosB6.b1, sgpmwrtipB1.a1, sgpmwrtipB4.a1, sgpmwrtipB5.a1, sgpmwrtipB6.a1 |
Start Date | Start Time | End Date | End Time |
---|---|---|---|
12/22/1993 | 0000 | 02/28/1994 | 2359 |
02/12/1994 | 0000 | 01/05/1995 | 2359 |
Subject: | Reprocess: Effect of BBSS ground check on MWR tuning functions |
DataStreams: | DsgpmwrlosB1.a0, DsgpmwrlosB1.a1, sgpmwrlosB1.a1 |
Description: | Due to concern over the impact of the Ground Check (a one-point calibration applied to the Vaisala sonde prior to launch) on the MWR tuning functions, I have recalculated the tuning functions without the ground check. The change in the tuning functions is slight and has only a very small (maximum of 1%) impact on the precipitable water vapor and cloud liquid water path values provided by the ARM microwave radiometers. TUNING FUNCTIONS The tuning functions relate microwave brightness temperatures measured by the the radiometer to those computed from simultaneous radiosondes using a model of microwave radiation transfer. The tuning functions are necessary to permit the use of the retrieval functions for precipitable water vapor and cloud liquid water which are based on the model calculations. The tuning functions are dependent only on the model; they are independent of the location and of the instrument (assuming it is properly calibrated). METHODOLOGY Barry Lesht, the BBSS instrument mentor, provided me with 325 soundings from the SGP central facility covering the period October 1992 - December 1993 from which he had removed the effect of the ground check. For each of these soundings I computed the microwave brightness temperatures at the frequencies used by the ARM microwave radiometers. Of these, 91 were determined to have occured during periods when the sky was clear and horizontally homogeneous on the basis of the standard deviation of the measured brightness temperature of the liquid-sensitive channel of the radiometer being less than 0.5 K for the period 10 minutes prior until 30 minutes subsequent to the sonde launch. The mean of the brightness temperatures measured during this time period were then used in a linear regression to determine the intercept and slope of the tuning functions. RESULTS: The new tuning functions are: 23.8 GHz: TB_model = 0.789 + 0.915 TB_measured (R2 = 0.994) 31.4 GHz: TB_model = 1.142 + 0.910 TB_measured (R2 = 0.988) These were applied to the MWR data acquired during the period October 1992 through December 1993 and compared with previous values. Only for values of PWV > 3 cm was the effect of the new tuning functions as much as 1%. For the 91 clear-sky soundings, the RMS difference between the preciptable water vapor from the MWR and from the BBSS was 0.1 cm; the mean difference was 0.00 cm. For 59 soundings during June 1993 (clear and cloudy sky), the mean difference in the PWV computed from the radiosondes (No ground check - ground check) was 0.05 cm; the RMS of the difference was 0.08 cm. Other observations/measurements impacted by this problem: qmemwrlos Suggested Corrections of the Problem: (e.g. change calibration factor and recompute, flag data with this comment, etc.) 1. The new tuning functions were implemented on all SGP MWRs on 5 Jan 1995. 2. The MWR data from Oct 92 - Dec 93 have been recalculated by the mentor and are available from him (as ten-minute averages in ASCII format) upon request. 3. A computer code has been provided by the mentor to the ARM Experiment Center to duplicate this reprocessing, if the PRB so desires. |
Measurements: | sgpmwrlosB1.a1:
DsgpmwrlosB1.a0:
DsgpmwrlosB1.a1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
01/01/1994 | 0000 | 12/31/1994 | 2359 |
Subject: | SGP/MWR/C1 - Data dropouts due to serial comm problems |
DataStreams: | sgpmwrlosC1.a1, sgpmwrlosC1.b1 |
Description: | Conflicts between the drop shipper program and the MWR operation program resulted in serial communication problems which ultimately manifested as spikes and dropouts in the data. |
Measurements: | sgpmwrlosC1.b1:
sgpmwrlosC1.a1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
12/07/1995 | 0300 | 12/10/1995 | 0600 |
Subject: | Precipitable Water Vapor (PWV) values at Hillsboro |
DataStreams: | sgp5mwravgB1.c1, sgpmwrlosB1.a0, sgpmwrlosB1.a1 |
Description: | DQR No: Platform: sgpmwrlos, sgp5mwravg Subject: Precipitable Water Vapor (PWV) values at Hillsboro 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) Period of time in question Begin Date 12/07/95 Time 03:00 (GMT) End Date 12/07/95 Time 16:00 (GMT) Begin Date 12/08/95 Time 20:00 (GMT) End Date 12/10/95 Time 06:00 (GMT) Data should be labeled: ___ questionable _X_ All data fields affected _X_ incorrect ___ Only some data fields affected _X_ wrong calibration ___ others Discussion of Problem: The precipitable water vapor was negative which is unreasonable. At the same time the brightness temperature in the 23.8 GHz was less than that in the 31.4 GHz for apparently clear skies. This is also unreasonable. The calibration needs to be checked and updated. 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.) Correct calibration. Data Processing Notes Date |
Measurements: | sgpmwrlosB1.a1:
sgp5mwravgB1.c1:
sgpmwrlosB1.a0:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
01/13/1996 | 0000 | 01/19/1996 | 2359 |
Subject: | SGP/MWR/B1/B5 - Calibration questionable |
DataStreams: | sgpmwrlosB1.a0, sgpmwrlosB1.a1, sgpmwrlosB5.a0, sgpmwrlosB5.a1 |
Description: | At the present time, calibrations at B1 and B5 appear out of date. SGP-B1 (Hillsboro, KS) Precipitable vapor amounts occasionally negative - calibration needs to be checked when sky becomes clear. Data quality is questionable. Precipitable vapor amounts about 0.6 cm less than integrated soundings. SGP-B5 (Morris, OK) Data from this instrument are missing for 12-15 Jan. Reason unknown. Because precipitable vapor amount was negative during 7-8 Jan, calibration is still suspect. Liquid water path appears positive for periods when sky is clear (positive bias). Data quality is questionable. Precipitable vapor amounts 0.3-0.5 cm less than integrated soundings. |
Measurements: | sgpmwrlosB5.a1:
sgpmwrlosB1.a1:
sgpmwrlosB1.a0:
sgpmwrlosB5.a0:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
02/12/1994 | 0000 | 04/04/1996 | 2359 |
Subject: | SGP/MWR/B1/B4/B5 - Reprocess: Error in MWR calibration |
DataStreams: | sgpmwrlosB1.a0, sgpmwrlosB1.a1, sgpmwrlosB4.a0, sgpmwrlosB4.a1, sgpmwrlosB5.a0, sgpmwrlosB5.a1 |
Description: | The effect of this error is small. At most, it results in a bias of about -0.015 cm in precipitable water vapor and -0.015 mm in liquid water path during clear sky conditions. The error is largest when the brightness temperatures are small (i.e. clear skies and low PWV). The error results from failing to correctly account for the effect of the Teflon window covering the radiometer mirror. Although the contribution of the window is subtracted when the tip curve data are reduced to determine the true zenith brightness temperature, it is not added back in when the zenith brightness temperature is used to calibrate the noise diode. This would still not be a problem if the contribution of the window where not subtracted (again) during zenith line-of-sight (LOS) operations. But it is and the net effect is to subtract the contribution of the window twice. The calibrations ('Noise Injection Temperatures') are off by a factor of 1.00164 and 1.00217 for the 23.8 and 31.4 GHz frequencies, respectively. The magnitude of the error is equal to the emissivity of the window multiplied by the difference between the brightness temperature and the temperature of the window. The latter is taken to be equal to the temperature of the internal blackbody target (which is about 10 deg C above ambient.) The emissivity of the window is 0.00164 at 23.8 GHz and 0.00217 at 31.4 GHz. For a reference temperature of 292.6 K and brightness temperatures of 32.3 and 20.8 K at 23.8 and 31.4 GHz respectively, this amounts to errors of -0.43 and -0.59 K at the respective frequencies. The average PWV for this date (5 April 1995) was 1.4 cm. At higher levels of PWV and for cloudy conditions, the brightness temperatures are higher and so the error is smaller. I will adjust the calibrations of all SGP radiometers to account for this problem by the end of tomorrow (4 April 1996). |
Measurements: | sgpmwrlosB5.a1:
sgpmwrlosB1.a1:
sgpmwrlosB4.a0:
sgpmwrlosB1.a0:
sgpmwrlosB5.a0:
sgpmwrlosB4.a1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
02/12/1994 | 0000 | 04/04/1996 | 2359 |
Subject: | SGP/MWR/B1/B4/B5 - Reprocess: MWR Tuning Functions |
DataStreams: | sgpmwrlosB1.a0, sgpmwrlosB1.a1, sgpmwrlosB4.a0, sgpmwrlosB4.a1, sgpmwrlosB5.a0, sgpmwrlosB5.a1 |
Description: | The 'tuning functions' used to adjust the equivalent brightness temperatures (TBs) measured by the ARM microwave radiometers (MWRs) are now believed to be both incorrect and unnecessary. They should no longer be used and the data (going back to 1992) that incorporated them should be reprocessed. By eliminating these tuning functions the radiometer retrievals would be independent of the soundings. BACKGROUND A recent comparison by Barry Lesht (ANL) of the precipitable water vapor (PWV) retrieved from the MWR-measured brightness temperatures against PWV derived by integrating along the trajectory of radiosonde ascents has revealed that the MWR values are about 90% of those derived from the soundings. This is directly attributable to the slope of the tuning function for the vapor-sensing channel (23.8 GHz) of 0.915 which is applied to the measured brightness temperatures prior to retrieval of PWV. The rationale behind the use of the tuning functions is that the radiation model (Liebe 87), on which the retrieval is based, is imperfect whereas the radiosondes represent 'ground truth.' Thus the observed brightness temperatures must be adjusted to match those calculated with the model using co-located soundings so that the retrieval yields precipitable vapor amounts that agree with the soundings. Tuning functions were developed for the present ARM MWRs using co-located soundings launched between October 1992 and December 1993. These were adjusted slightly in January 1995 to account for the effects of the 1-point calibration check performed prior to launch (see DQR P950110.1): 23.8 GHz: TB_model = 0.789 + 0.915 TB_measured (R2 = 0.998) 31.4 GHz: TB_model = 1.142 + 0.910 TB_measured (R2 = 0.984) However, repeating this exercise for soundings launched during 1994 and 1995 (excepting those that were mis-calibrated by the manufacturer; see D960229.1) it now appears that the model-calculated brightness temperatures are in much closer agreement with the measured values and that the tuning functions account more for variations in the radiosonde calibration than for any deficiencies in the radiation model. Consequently, it appears that the present tuning functions are incorrect and bias the retrieved PWV low by 10%. In addition, given the present agreement between measured and modeled brightness temperatures, the tuning functions are also unnecessary. METHODOLOGY Brightness temperatures measured with microwave radiometer (MWR) serial number 10, which was deployed at the central facility in December 1993, have been compared against calculations using measurements from the co-located Balloon-Borne Sounding System (BBSS). The results are summarized in two tables. In each table, the calibration dates of the sondes and MWR are listed as well as the time period and number of samples included in each regression. Each MWR sample is a 40-minute average, centered on the time of the sonde launch, of the microwave brightness temperature. In order to include only clear sky conditions, samples for which the standard deviation of the liquid-sensing (31.4 GHz) channel exceeded 0.3 K were eliminated. To assure that the water vapor was reasonably homogeneous horizontally, samples for which the standard deviation in the vapor-sensing (23.8 GHz) channel exceeded 0.4 K (in 1995) or 0.5 K (in 1994) were eliminated. The 1994 threshold is larger in order to increase the number of samples and reduce the standard error in the results. The microwave radiometer measurements used in this comparison have been reprocessed to account for calibration changes and other problems (see P940813.1) TB vs PWV The first table is a comparison of microwave brightness temperature (TB_mwr) regressed against the precipitable water vapor (PWV) computed by integrating along the trajectory of the radiosonde ascent. The sondes launched during May - December 1994 are compared against two sets of MWR data; the first uses the May 1994 calibration, and the second uses the calibration of July 1994. A comparison is also made of TB_model vs PWV ('Liebe87') for reference. The intercepts indicate the contribution due to molecular oxygen (i.e. the tail of the 60 GHz line) which is affected by temperature and pressure. Note that the 'Liebe87' intercepts vary seasonally as the temperature changes. Note also that the effect of MWR calibration changes is most evident in the intercept: offsets of 1-2 K are observed. Because the MWR calibration values represent the slope of the radiometer equation (see Appendix), the magnitude of the offset is largest at 0 K (i.e. the intercept) and declines to zero at ambient temperature (~290 K). The slope of the regression is essentially unaffected by the MWR calibration. Variations in the slope of the regression correlate with sonde calibration date. The sondes calibrated in May 1994 or later appear to yield much closer agreement between the measured brightness temperatures and those calculated with the Liebe 87 model than those calibrated in January 1994 or earlier, with which the present tuning functions were developed. TABLE 1. Microwave brightness temperature vs. precipitable water vapor Relationship: TB_mwr (K) = intercept (K) + slope (K/cm) * PW_sonde (cm) Standard Error of the intercepts and slopes are given in parentheses. Date of Date of Period ------ 23.8 GHz ----- ----- 31.4 GHz ----- Sonde Cal MWR tip Covered N intercept slope intercept slope 1991-93 92-93 Oct92-Dec93 91 6.7 14.7 8.1 5.3 1992,93 Dec 93 Jan-Feb 94 85 6.9(0.19) 15.8(0.26) 8.8(0.13) 5.6(0.17) 1992,93 Liebe87 Jan-Feb 94 85 6.5(0.02) 13.8(0.03) 8.9(0.07) 4.5(0.09) Jun 93 Dec 93 Apr 94 16 10.6(1.11) 14.8(0.55) 10.1(0.51) 5.6(0.25) Jun 93 Liebe87 Apr 94 16 6.9(0.05) 13.6(0.02) 8.1(0.09) 5.0(0.05) 1992,93 May 94 May-Jun 94 48 7.0(1.03) 14.9(0.45) 7.8(0.41) 5.7(0.17) 1992,93 Jul 94 May-Jun 94 48 5.1(1.03) 14.9(0.44) 6.6(0.39) 5.7(0.17) 1992,93 Liebe87 May-Jun 94 48 7.1(0.11) 13.5(0.05) 8.4(0.16) 4.9(0.07) Jan 94 Dec 93 Feb-May 94 95 7.6(0.27) 14.3(0.14) 8.5(0.15) 5.5(0.08) Jan 94 Liebe87 Feb-May 94 95 6.9(0.05) 13.6(0.02) 8.1(0.09) 5.0(0.05) May 94 May 94 Jun-Aug 94 78 12.3(1.04) 13.0(0.34) 11.0(0.39) 4.8(0.13) May 94 Jul 94 Jun-Aug 94 78 10.3(1.04) 13.1(0.34) 9.8(0.39) 4.8(0.13) May 94 Liebe87 Jun-Aug 94 78 7.8(0.22) 13.3(0.07) 8.6(0.29) 4.9(0.10) Jun 94 May 94 Jul-Dec 94 57 8.3(0.37) 13.6(0.21) 8.8(0.19) 5.2(0.11) Jun 94 Jul 94 Jul-Dec 94 57 6.4(0.37) 13.6(0.21) 7.7(0.18) 5.2(0.10) Jun 94 Liebe87 Jul-Dec 94 57 6.9(0.08) 13.5(0.04) 8.3(0.10) 4.9(0.06) Aug 94 May 94 Sep-Dec 94 90 7.4(0.15) 13.5(0.09) 8.8(0.11) 5.1(0.07) Aug 94 Jul 94 Sep-Dec 94 90 5.5(0.14) 13.6(0.09) 7.8(0.12) 5.0(0.07) Aug 94 Liebe87 Sep-Dec 94 90 6.8(0.05) 13.6(0.03) 8.6(0.09) 4.9(0.06) |
Measurements: | sgpmwrlosB5.a1:
sgpmwrlosB1.a1:
sgpmwrlosB4.a0:
sgpmwrlosB1.a0:
sgpmwrlosB5.a0:
sgpmwrlosB4.a1:
|
Start Date | Start Time | End Date | End Time |
---|
Subject: | |
DataStreams: | |
Description: | |
Measurements: |
Start Date | Start Time | End Date | End Time |
---|---|---|---|
08/19/1995 | 0000 | 08/20/1995 | 2359 |
08/26/1995 | 0000 | 09/04/1995 | 2359 |
07/01/1996 | 1825 | 07/23/1996 | 2300 |
Subject: | SGP/MWR/C1 - Loss of thermal stabilization |
DataStreams: | sgp1mwravgC1.c1, sgp5mwravgC1.c1, sgpmwrlosC1.a1, sgpmwrlosC1.b1 |
Description: | Periodically during August and September 1995 all microwave radiometers at the SGP CART generated error messages in the Site Operations Log like: Time: Sat Aug 19 18:41:20 1995 MWRLOS.C1, tkxc: Value above Maximum. This indicates that the temperature of the microwave hardware (specifically, the cross-coupler or "xc") exceeded its controlled temperature (47-52 deg C) at which point it was no longer thermally stabilized and the gain was uncontrolled. During these periods which typically last about 8 hours from about local noon until about sunset the data behave anomalously and should be considered invalid. Specifically the 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. The 'Tkxc' field appears ONLY in the a0-level data and does NOT appear in either the a1 (mwrlos) or c1 (mwr5avg) files. Therefore THESE ANOMALOUS VALUES HAVE BEEN INCLUDED IN THE 5-MINUTE AVERAGES. The microwave hardware is thermally stabilized to about +/- 0.1 deg C by resistive heating. When the internal temperature rises above the set point the thermal stabilization of the instrument gain is lost. >From an examination of the component temperature data it appears that increasing the set point temperature to about 55 deg C (328 K) would prevent a re-ocurrance of this problem at the SGP. The manufacturer, Radiometrics, concurs that raising the set point will fix this problem and will not cause other problems. I will have to carefully examine the MCTEX data to determine whether this will be a problem for the TWP. The manufacturer and I had discussed this possibility prior to building the TWP MWRs (S/N 015, 016, and 017) and those instruments have set points above 50 deg C. Note that MWR 018 has a set point near 52 deg C (like the TWP models) but it still experienced a few loss-of-stabilization events. Note that the instruments with the lowest set points had the most loss-of-stabilization events. |
Measurements: | sgp5mwravgC1.c1:
sgpmwrlosC1.b1:
sgp1mwravgC1.c1:
sgpmwrlosC1.a1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
07/01/1996 | 2030 | 07/28/1996 | 0015 |
Subject: | Loss of thermal stabilization |
DataStreams: | sgpmwrlosB1.a1 |
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. |
Measurements: | sgpmwrlosB1.a1:
|
Start Date | Start Time | End Date | End Time |
---|
Subject: | |
DataStreams: | |
Description: | |
Measurements: |
Start Date | Start Time | End Date | End Time |
---|---|---|---|
10/27/1997 | 2000 | 11/10/1997 | 1940 |
Subject: | Manually corrected error in header files |
DataStreams: | sgpmwrlosB1.a0, sgpmwrlosB1.a1, sgpmwrlosB5.a0, sgpmwrlosB5.a1, sgpmwrtipB5.a0 |
Description: | On 10/27/97 at 20:00 UTC, an error was made while remotely editing the MWR configuration file. This produced an error in the data file header which made the normal processing programs fail. The problem was identified on 11/10/97. The configuration file at BF1 was corrected on 11/11/97 at 19:40. MWR.BBF5 wasremoved from service on 11/5/97 17:54. The configuration file at BF5 was corrected prior to reinstalling the MWR on 1/9/98. The file headers of these data were reconstructed and the data were delivered to the Archive on 11/26/97 for MWR.BF1 and on 12/3/97 for MWR.BF5. This DQR is being filed to note that the headers were manually recreated. The data should be unaffected. This DQR is based on information obtained from Victor Morris and Robin Perez. |
Measurements: | sgpmwrtipB5.a0:
sgpmwrlosB5.a1:
sgpmwrlosB1.a1:
sgpmwrlosB1.a0:
sgpmwrlosB5.a0:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
09/03/1998 | 2200 | 09/15/1998 | 2100 |
Subject: | SGP/MWR/B1/B4/B6 - Instruments in calibration (tip) mode |
DataStreams: | sgpmwrlosB1.a0, sgpmwrlosB1.a1, sgpmwrlosB4.a0, sgpmwrlosB4.a1, sgpmwrlosB6.a0, sgpmwrlosB6.a1 |
Description: | These instruments were placed in calibration (tip) mode at the same time as the central facility (CF) instrument. Line-of-sight (LOS) data are not collected while the instrument is in tip mode. Note that the instrument at Hillsboro, KS (B1) is not reachable by telnet; it will not begin acquiring zenith line-of-sight data until its computer is rebooted. |
Measurements: | sgpmwrlosB1.a1:
sgpmwrlosB4.a0:
sgpmwrlosB6.a0:
sgpmwrlosB1.a0:
sgpmwrlosB4.a1:
sgpmwrlosB6.a1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
04/03/1995 | 0000 | 10/12/1998 | 1900 |
Subject: | SGP/MWR/B1/B4/B6/C1 - software change |
DataStreams: | sgpmwrlosB1.a0, sgpmwrlosB1.a1, sgpmwrlosB4.a0, sgpmwrlosB4.a1, sgpmwrlosB6.a0, sgpmwrlosB6.a1, sgpmwrlosC1.a1, sgpmwrlosC1.b1, sgpmwrtipB1.a0, sgpmwrtipB4.a0, sgpmwrtipB6.a0 |
Description: | The MWR operating software was changed on 12 October 1998 to provide additional functionality as described below. This change affects the format of the raw and ingested data. NEW FEATURES 1. Faster sampling rate Standard line-of-sight (LOS) observations can now be acquired at 15-second intervals vs. 20-second intervals previously. (The standard LOS cycle is comprised of one sky sample per blackbody sample and gain update.) 2. More flexible sampling strategy Multiple sky observations can be acquired during a LOS cycle, up to 1024 per gain update. This permits sky samples to be acquired at intervals of 2.67 seconds for improved temporal resolution of cloud liquid water variations and better coordination with the millimeter cloud radar during IOPs. 3. Separation of zenith LOS observations from TIP data When the radiometer is in TIP mode, the zenith LOS observations are now extracted, the PWV and LWP computed and reported separately in the output file. This eliminates the periods of missing LOS data during calibration checks/updates. 4. Automatic self-calibration The software now permits the calibration to be updated at specified intervals or continuously. In the first case, LOS mode is automatically changed to TIP mode at user-specified intervals or whenever clear sky conditions occur, the tip data reduced, the calibration updated ,and the radiometer returned to LOS mode without operator intervention. In the second case, the radiometer is continuously is TIP mode until changed by the operator. 5. Graphical user display The graphical display is comprised of a status display, a message display, a temperature plot, a plot of the retrieved PWV and LWP, and (in TIP mode) a plot of the latest tip curves. Editor's Note: The SGP.C1 data were reprocessed in 2004 and enhancement #3 described above was applied to the data prior to Oct 1998. The SGP.BF data are queued for reprocessing as well. |
Measurements: | sgpmwrtipB1.a0:
sgpmwrlosB1.a1:
sgpmwrlosB4.a0:
sgpmwrlosB6.a0:
sgpmwrlosC1.b1:
sgpmwrtipB6.a0:
sgpmwrlosB1.a0:
sgpmwrtipB4.a0:
sgpmwrlosC1.a1:
sgpmwrlosB4.a1:
sgpmwrlosB6.a1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
03/10/1998 | 2000 | 05/19/1998 | 0000 |
Subject: | SGP/MWR/B1 out of calibration |
DataStreams: | sgpmwrlosB1.a0, sgpmwrlosB1.a1 |
Description: | A shift in the calibration of MWR/B1 occurred on 10 March 1998, apparently due to a power failure (see P980513.1). The calibration was corrected on 19 May. |
Measurements: | sgpmwrlosB1.a1:
sgpmwrlosB1.a0:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
07/21/1993 | 1406 | 01/12/1999 | 2359 |
Subject: | SGP/MWR/B1/B4/B5/B6/C1 - software upgrade (version 3.27) |
DataStreams: | sgpmwrlosB1.a1, sgpmwrlosB4.a1, sgpmwrlosB5.a1, sgpmwrlosB6.a1, sgpmwrlosC1.a1, sgpmwrlosC1.b1, sgpmwrtipB1.a0, sgpmwrtipB4.a0, sgpmwrtipB5.a0, sgpmwrtipB6.a0 |
Description: | At 00:00 GMT on 7 January version 3.27 of the MWR operating program was installed and made operational at the SGP central facility (C1). No problems were noted over the next few days and the boundary facility MWRs (B1, B4, B5, B6) were upgraded at 20:00 GMT on 11 January. This version includes a beam width correction I developed as well as providing the capability to automatically level the elevation mirror (that is, to automatically detect and correct offsets in the elevation angle stepper motor position.) On 12 January I discovered that the '486-based MWR computers at B1, B4 and B6 were not executing the system command to move and rename the data files so that the ARM data system could retrieve them. Reducing the length of the storage arrays in the auto-leveling feature from 1000 to 250 resolved the problem. This results in the auto-leveling being based on only 4 hours of clear sky data rather than 16 hours at B5 and C1. This version of the program is 3.28. Version 3.27 (running at B5 and C1) can be installed if and when these computers are upgraded to Pentium-class machines. The improvement in the quality of the tip curves resulting from the auto-leveling has been dramatic: differences in the brightness temperatures at 3 airmasses (19.5 and 160.5 degrees) have been reduced from +/- 5 K to +/- 0.5 K. The goodness-of-fit coefficient for the tip curves has improved from about 0.995 to over 0.998. In order to take full advantage of this improvement to detect and reject cloudy tip curves, the minimum value of the goodness-of-fit coefficient for a valid tip curve has been increased from 0.995 to 0.998. Editor's Note: The SGP.C1 data were reprocessed in 2004 to produce a common DOD for all time. The 1996-1998 data reprocessing included beam width and mirror-leveling corrections, but the data prior to that range did not have these corrections applied. |
Measurements: | sgpmwrtipB1.a0:
sgpmwrlosB5.a1:
sgpmwrtipB5.a0:
sgpmwrlosB1.a1:
sgpmwrlosC1.b1:
sgpmwrtipB6.a0:
sgpmwrtipB4.a0:
sgpmwrlosC1.a1:
sgpmwrlosB4.a1:
sgpmwrlosB6.a1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
10/29/1998 | 0000 | 08/12/1999 | 2359 |
Subject: | SGP/MWR/B1/B4/B5/B6 - data file split at 23:59 |
DataStreams: | sgpmwrlosB1.a1, sgpmwrlosB1.b1, sgpmwrlosB4.a1, sgpmwrlosB4.b1, sgpmwrlosB5.a1, sgpmwrlosB5.b1, sgpmwrlosB6.a1, sgpmwrlosB6.b1, sgpmwrtipB1.a1, sgpmwrtipB4.a1, sgpmwrtipB5.a1, sgpmwrtipB6.a1 |
Description: | A problem with the MWR operating software has been corrected. However, several files were generated that contain one record of data collected at midnight but labeled with the previous day's date. |
Measurements: | sgpmwrlosB5.a1:
sgpmwrlosB1.a1:
sgpmwrtipB6.a1:
sgpmwrlosB6.b1:
sgpmwrlosB4.b1:
sgpmwrtipB4.a1:
sgpmwrtipB5.a1:
sgpmwrlosB1.b1:
sgpmwrtipB1.a1:
sgpmwrlosB4.a1:
sgpmwrlosB5.b1:
sgpmwrlosB6.a1:
|