DQR ID | Subject | Data Streams Affected |
---|---|---|
D020905.3 | SGP/MWR/C1 - IRT not insulated | sgpmwrlosC1.a1, sgpmwrlosC1.b1 |
D080103.2 | SGP/MWR/C1 - Missing data | sgpmwrlosC1.b1 |
D940820.1 | SGP/MWR/C1 - IRT rain lid removal | sgpmwrlosC1.a1, sgpmwrlosC1.b1 |
D950110.2 | SGP/MWR/C1 - Data dropouts due to serial comm problems | sgpmwrlosC1.a1, sgpmwrlosC1.b1 |
D950501.2 | SGP/MWR/C1 - IR thermometer calibration check | sgpmwrlosC1.a1, sgpmwrlosC1.b1 |
D960405.1 | SGP/MWR/C1 - Loss of thermal stabilization | sgp1mwravgC1.c1, sgp5mwravgC1.c1, sgpmwrlosC1.a1, sgpmwrlosC1.b1 |
D960422.1 | SGP/MWR/C1 - Radio Frequency Interference during IOP | sgp5mwravgC1.c1, sgpmwrlosC1.a1, sgpmwrlosC1.b1 |
D961114.1 | SGP/MWR/C1 - IRT lens replaced | sgpmwrlosC1.a1, sgpmwrlosC1.b1 |
D961120.1 | SGP/MWR/B1/B4/B5/B6/C1 - Thermal Stabilization Adjustment | sgp1mwravgC1.c1, sgp5mwravgB1.c1, sgp5mwravgB4.c1, sgp5mwravgB5.c1, sgp5mwravgB6.c1, sgp5mwravgC1.c1, sgpmwrlosB1.a0, sgpmwrlosB1.a1, sgpmwrlosB4.a0, sgpmwrlosB4.a1, sgpmwrlosB5.a0, sgpmwrlosB5.a1, sgpmwrlosB6.a0, sgpmwrlosB6.a1, sgpmwrlosC1.a1, sgpmwrlosC1.b1 |
D961220.1 | SGP/MWR/C1 - IRT Calibration check | sgpmwrlosC1.a1, sgpmwrlosC1.b1 |
D970509.1 | SGP/MWR/C1 - IRT Calibration | sgpmwrlosC1.a1, sgpmwrlosC1.b1 |
D980130.1 | SGP/MWR/C1 - IRT offline | sgpmwrlosC1.a1, sgpmwrlosC1.b1 |
D980507.1 | SGP/MWR/C1 - IRT lens replaced | sgpmwrlosC1.a1, sgpmwrlosC1.b1 |
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 |
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 |
---|---|---|---|
01/19/1994 | 0000 | 11/27/1998 | 1930 |
Subject: | SGP/MWR/C1 - IRT not insulated |
DataStreams: | sgpmwrlosC1.a1, sgpmwrlosC1.b1 |
Description: | The downwelling IRT was insufficiently insulated to maintain an internal reference temperature above 0 degrees C (P971213.1). Measurements of sky temperature were over-estimated when instrument was below freezing. |
Measurements: | sgpmwrlosC1.b1:
sgpmwrlosC1.a1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
07/21/1993 | 1809 | 07/23/1993 | 1541 |
08/07/1993 | 2143 | 08/09/1993 | 1308 |
08/14/1993 | 2233 | 08/16/1993 | 1300 |
08/29/1993 | 1207 | 08/31/1993 | 1206 |
09/17/1993 | 2158 | 09/20/1993 | 1311 |
10/02/1993 | 1612 | 10/04/1993 | 1338 |
10/09/1993 | 0741 | 10/11/1993 | 1319 |
11/12/1993 | 1207 | 11/15/1993 | 1413 |
11/19/1993 | 2027 | 11/21/1993 | 1957 |
12/14/1993 | 2300 | 03/21/1994 | 1759 |
03/28/1994 | 1459 | 03/30/1994 | 2225 |
05/16/1994 | 1900 | 05/19/1994 | 2018 |
06/22/1994 | 1600 | 07/11/1994 | 1859 |
07/16/1994 | 0300 | 07/19/1994 | 2006 |
09/03/1994 | 1647 | 09/05/1994 | 1341 |
09/09/1994 | 2325 | 09/11/1994 | 1543 |
12/17/1994 | 0049 | 12/19/1994 | 1441 |
01/05/1995 | 0000 | 01/05/1995 | 2359 |
01/28/1995 | 0054 | 01/30/1995 | 1443 |
04/01/1995 | 0000 | 04/03/1995 | 1610 |
05/09/1995 | 2200 | 05/11/1995 | 2350 |
06/24/1995 | 0903 | 06/26/1995 | 0159 |
07/07/1995 | 1625 | 07/10/1995 | 1409 |
07/19/1995 | 1741 | 07/21/1995 | 1906 |
07/28/1995 | 1900 | 07/31/1995 | 1918 |
08/22/1995 | 1616 | 08/25/1995 | 2359 |
12/01/1995 | 1434 | 01/11/1996 | 2214 |
01/12/1996 | 2000 | 01/23/1996 | 2030 |
01/23/1996 | 2332 | 02/08/1996 | 2359 |
08/06/1996 | 0000 | 08/06/1996 | 2359 |
09/04/1996 | 1910 | 09/08/1996 | 2359 |
09/14/1996 | 0700 | 09/16/1996 | 1759 |
09/30/1996 | 0000 | 09/30/1996 | 2359 |
12/01/1996 | 0000 | 12/01/1996 | 2359 |
07/01/1997 | 0000 | 07/01/1997 | 2359 |
02/20/1998 | 2339 | 02/22/1998 | 0042 |
05/04/1998 | 0000 | 05/04/1998 | 2359 |
07/18/1998 | 0337 | 07/20/1998 | 1355 |
09/28/1998 | 0000 | 09/28/1998 | 2359 |
10/10/1998 | 2359 | 10/12/1998 | 1959 |
10/17/1998 | 1705 | 10/19/1998 | 1535 |
12/25/1998 | 2233 | 12/28/1998 | 2026 |
02/06/1999 | 1235 | 02/08/1999 | 1652 |
03/13/1999 | 2048 | 03/15/1999 | 2040 |
07/23/1999 | 2059 | 07/26/1999 | 1408 |
12/04/1999 | 0800 | 12/06/1999 | 1821 |
01/07/2000 | 1446 | 02/02/2000 | 2224 |
05/24/2000 | 1455 | 05/31/2000 | 1505 |
06/06/2000 | 1620 | 06/14/2000 | 1451 |
09/01/2000 | 2200 | 09/05/2000 | 1526 |
09/15/2000 | 2057 | 09/18/2000 | 1339 |
09/23/2000 | 1236 | 09/25/2000 | 1430 |
01/13/2001 | 2011 | 01/16/2001 | 1647 |
02/24/2001 | 0230 | 02/26/2001 | 1508 |
03/03/2001 | 0701 | 03/05/2001 | 1546 |
03/10/2001 | 0702 | 03/12/2001 | 1535 |
03/17/2001 | 0702 | 03/19/2001 | 1422 |
03/24/2001 | 0703 | 03/26/2001 | 1516 |
03/30/2001 | 2038 | 04/02/2001 | 1423 |
05/05/2001 | 1042 | 05/07/2001 | 1514 |
05/18/2001 | 1534 | 05/21/2001 | 1451 |
06/22/2001 | 2200 | 06/25/2001 | 1438 |
06/30/2001 | 0616 | 07/02/2001 | 1435 |
07/28/2001 | 1944 | 07/30/2001 | 1357 |
08/24/2001 | 1348 | 08/27/2001 | 1751 |
09/07/2001 | 1842 | 09/10/2001 | 1439 |
09/15/2001 | 1533 | 09/17/2001 | 1459 |
10/13/2001 | 0033 | 10/15/2001 | 1526 |
11/03/2001 | 0840 | 11/05/2001 | 1613 |
11/10/2001 | 0558 | 11/13/2001 | 1518 |
11/16/2001 | 1701 | 11/19/2001 | 1706 |
12/21/2001 | 2153 | 12/24/2001 | 1442 |
01/30/2002 | 0845 | 02/11/2002 | 1632 |
03/02/2002 | 0339 | 03/04/2002 | 1533 |
03/09/2002 | 0340 | 03/11/2002 | 1621 |
06/26/2002 | 1639 | 06/28/2002 | 2057 |
09/01/2002 | 1002 | 09/03/2002 | 1332 |
12/21/2002 | 1124 | 12/23/2002 | 1510 |
01/04/2003 | 0703 | 01/06/2003 | 1529 |
08/09/2003 | 0037 | 08/11/2003 | 1456 |
08/23/2003 | 2101 | 08/25/2003 | 1456 |
10/12/2003 | 2025 | 10/14/2003 | 1414 |
11/29/2003 | 1840 | 12/01/2003 | 1502 |
01/24/2004 | 0743 | 01/26/2004 | 1505 |
02/14/2004 | 2316 | 02/17/2004 | 1520 |
09/04/2004 | 0250 | 09/07/2004 | 1419 |
10/09/2004 | 0745 | 10/11/2004 | 1739 |
10/16/2004 | 2250 | 10/18/2004 | 1355 |
11/13/2004 | 1849 | 11/15/2004 | 1521 |
12/03/2004 | 1940 | 12/06/2004 | 1454 |
01/15/2005 | 0652 | 01/18/2005 | 1446 |
01/22/2005 | 1449 | 01/24/2005 | 1444 |
06/10/2005 | 2118 | 06/13/2005 | 1603 |
08/05/2005 | 1701 | 08/30/2005 | 2001 |
10/07/2005 | 1658 | 11/16/2005 | 1945 |
11/18/2005 | 1801 | 11/21/2005 | 1521 |
11/23/2005 | 2201 | 11/25/2005 | 1550 |
11/26/2005 | 0101 | 11/28/2005 | 1543 |
12/03/2005 | 1043 | 12/05/2005 | 1559 |
01/14/2006 | 1822 | 01/17/2006 | 1512 |
01/21/2006 | 0708 | 01/23/2006 | 1515 |
02/03/2006 | 1903 | 02/06/2006 | 1533 |
02/25/2006 | 0730 | 02/27/2006 | 1420 |
07/01/2006 | 2225 | 07/03/2006 | 1413 |
11/28/2006 | 2143 | 12/01/2006 | 1911 |
06/09/2007 | 1150 | 06/11/2007 | 1300 |
07/07/2007 | 1642 | 07/09/2007 | 1304 |
08/03/2007 | 1601 | 11/19/2007 | 2135 |
12/22/2007 | 2112 | 12/24/2007 | 1504 |
05/25/2008 | 1815 | 05/27/2008 | 1335 |
06/06/2008 | 1512 | 06/09/2008 | 0238 |
Subject: | SGP/MWR/C1 - Missing data |
DataStreams: | sgpmwrlosC1.b1 |
Description: | Data are missing and unrecoverable. |
Measurements: | sgpmwrlosC1.b1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
01/01/1994 | 0000 | 08/16/1994 | 2359 |
Subject: | SGP/MWR/C1 - IRT rain lid removal |
DataStreams: | sgpmwrlosC1.a1, sgpmwrlosC1.b1 |
Description: | The IR thermometer (or IRT) was deployed at the SGP central facility in January 1994 with an automatic mechanism which closed a protective lid over the zenith-viewing lens when a moisture detector indicated condensation or precipitation. Since that time the 120 VAC-to-12 VAC transformer in the lid mechanism has failed 5 times with an average downtime of two weeks. In addition, the collar by which the (normally open) lid is attached to the lens barrel of the IRT has made it difficult for site operations personnel to observe the condition of the IRT lens. As a result, dirt and insects have been able to accumulate on the lens. This has resulted in long periods of invalid data. To alleviate these problems the lid mechanism was removed from service on 16 August at my recommendation. It is anticipated that condensation and precipitation will result in invalid data. However, these events should be readily detectable because the observed IR temperature will closely match the ambient temperature (e.g. the temperature of the moisture on the lens) which is usually much greater than the sky or cloud base temperature normally measured. I believe that this will not result in a large increase in invalid data because these data would have been invalid anyway when the lid was closed. (This situation is now the same as for the other radiometers at the site.) In addition, removing the attaching collar from the lens barrel will prevent insects from nesting in it, and will permit site operations personnel easy access to the lens so that they may more easily maintain it in a clean condition. A summary of the quality of the IR thermometer data in general, including notes on the performance of the protective lid, follows: JANUARY 1994 19-JAN: Operational. No IR data collected. FEBRUARY 1994 2-FEB: Failure of lid reported. Transformer burned out. 15-FEB: IRT returned to service. 24-FEB: Valid data begin. MARCH 1994 3-MAR: Failure of lid reported. Transformer burned out. 8-MAR: IRT returned to service. 8-MAR: Cable problems reported. 17-MAR: Cable problems resolved. IRT returned to service. 17-27-MAR: Comparison with AERI indicates IRT 1-10 deg C higher; increasing error with decreasing temperatures. Probably due to dirt/debris on lens. Also, IRT calibration not valid below -50 deg C (223 K). 21-MAR: Problems with O-ring on lid sticking reported/repaired. APRIL 1994 Data values below -50 deg C (223 K) not valid - below range of calibration. Otherwise data within 2-3 degrees of AERI. 24-APR: Large (10-20 Deg C) offset between IRT and AERI develops. MAY 1994 7-MAY: Mentor visits site, observes spider's nest and dead insects inside collar attaching lid to lens barrel in optical path of instrument. Probably the source of the offset between IRT and AERI during late and April. 9-MAY: Insects removed, lens cleaned by site operations personnel. Agreement between IRT and AERI within 1 deg C. 23-MAY: Failure of lid reported. Transformer burned out. JUNE 1994 22-JUN: Rebuilt/redesigned lid mechanism put in service; data collection computer fails same day. JULY 1994 11-JUL: Computer returned to service. Agreement between IRT and AERI within 1 deg C. 22-JUL: Failure of lid reported. Transformer burned out. AUGUST 1994 3-AUG: IRT returned to service. 12-AUG: Failure of lid reported. Transformer burned out. 16-AUG: Lid mechanism abandoned. |
Measurements: | sgpmwrlosC1.b1:
sgpmwrlosC1.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 |
---|---|---|---|
04/30/1995 | 1630 | 04/30/1995 | 1700 |
Subject: | SGP/MWR/C1 - IR thermometer calibration check |
DataStreams: | sgpmwrlosC1.a1, sgpmwrlosC1.b1 |
Description: | Mentor used an Everest model 1000 ambient temperature target (emis.=0.98) to check the calibration of the Heiman IR pyrometer (IR thermometer). Data collected during this period will be anomalous due to the modifications of the instrument settings required to facilitate the calibration. The emissivity of the instrument was changed to match the target; units were changed to deg C (from K) to match the target LCD units; integration time on the instrument was changed to 3 seconds (from 1 second). Centered the target on the instrument lens and allowed it to rest on the lens barrel so that it filled the field of view of the instrument. Both the instrument LCD and target LCD indicated 16.7 deg C. Noted that although the lens appeared clean, there was some liquid water around the edge which formed a meniscus with the inside of the lens barrel. Wiped this away with a clean, lint-free cotton cloth. Replaced the target on the lens barrel; both instrument and target then indicated 17.1 deg C. Reset the instrument emissivity (=1.0), the units (kelvins) and the integration time (=1 sec). The IRT was deployed in December 1993. Its calibration appears to have been stable since deployment. Liquid water around the edge of the lens appears to be out of the field of view and does not appear to affect the data. |
Measurements: | sgpmwrlosC1.b1:
sgpmwrlosC1.a1:
|
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 |
---|---|---|---|
04/09/1996 | 1337 | 04/09/1996 | 1834 |
04/10/1996 | 0625 | 04/10/1996 | 1823 |
04/11/1996 | 1149 | 04/11/1996 | 1649 |
04/12/1996 | 0917 | 04/12/1996 | 1858 |
04/13/1996 | 0605 | 04/13/1996 | 1801 |
Subject: | SGP/MWR/C1 - Radio Frequency Interference during IOP |
DataStreams: | sgp5mwravgC1.c1, sgpmwrlosC1.a1, sgpmwrlosC1.b1 |
Description: | During the specified times a strong, continuous signal was measured by the 31.4 GHz of the MWR. The signal was present in all 31.4 GHz measurements including the sky measurement, the internal reference target measurement, and the measurement of the internal noise injection source from which the instantaneous instrument gain is computed. The source of the interference has not yet been identified. Because the gain is computed using the difference of the noise injection and target measurements, and because the sky brightness temperature is computed relative to the internal target temperature, the data appear anomalous only for a period of an hour after the interference starts and ends. This is due to the low pass filter applied to the instantaneous gain. However the data should be considered invalid or at least questionable during the entire period for which the interference was present. |
Measurements: | sgp5mwravgC1.c1:
sgpmwrlosC1.b1:
sgpmwrlosC1.a1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
01/19/1994 | 0000 | 10/28/1996 | 1618 |
Subject: | SGP/MWR/C1 - IRT lens replaced |
DataStreams: | sgpmwrlosC1.a1, sgpmwrlosC1.b1 |
Description: | The lens of the uplooking "IR thermometer" (a 10 micrometer pyrometer) was replaced on 28 October 1996 at 16:18 GMT. At the time the sky was heavily overcast (0.1-0.5 mm liquid water path, IR temperature = 281-285 K) with about 4 cm integrated water vapor. A comparison was carried out against the Atmospheric Emitted Radiance Interferometer (AERI) both prior to and subsequent to the lens change. The statistics of the differences (IRT-AERI) are as follows: Mean (K) Std Dev (K) No. Before: 0.64 0.24 122 After: 0.35 0.20 89 In addition, the downward step change in the time series plot of the temperature difference (IRT-AERI) at the time of the lens replacement is obvious. This suggests, but is not conclusive evidence, that the primary cause of the differences between the IRT and AERI reported previously (PIF no. P960809.2) may have been the weather-worn lens. However, as this instrument has not been calibrated since it was deployed in December 1993, there may also be calibration drift to contend with. Arrangements are being pursued with NREL to check the calibration of this instrument. It is preferable to carry out the IRT vs AERI comparison for clear sky conditions to be certain that both instruments are observing the same scene at the moment when they make sky measurements. However, it is not possible at this time of the year to carry out a clear sky comparison because the integrated water vapor is generally less than 2.0 cm which means that the IR temperature is less than 223 K, the lower limit of the D/A converter on the IRT. On the positive side, the AERI and the IRT are within 10 m of each other and have similar fields of view (about 2 degrees) so their scenes should be comparable for clear or cloudy skies. |
Measurements: | sgpmwrlosC1.b1:
sgpmwrlosC1.a1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
08/01/1996 | 0000 | 08/31/1996 | 2359 |
Subject: | SGP/MWR/B1/B4/B5/B6/C1 - Thermal Stabilization Adjustment |
DataStreams: | sgp1mwravgC1.c1, sgp5mwravgB1.c1, sgp5mwravgB4.c1, sgp5mwravgB5.c1, sgp5mwravgB6.c1, sgp5mwravgC1.c1, sgpmwrlosB1.a0, sgpmwrlosB1.a1, sgpmwrlosB4.a0, sgpmwrlosB4.a1, sgpmwrlosB5.a0, sgpmwrlosB5.a1, sgpmwrlosB6.a0, sgpmwrlosB6.a1, sgpmwrlosC1.a1, sgpmwrlosC1.b1 |
Description: | In order to correct a thermal stabilization problem identified earlier I adjusted the thermal set point of the microwave radiometers at the SGP upward from 48-50 deg C to 55 deg C in early August 1996 according to the schedule given below. B6 5 August 1996 C1 6 August 1996 B1 7 August 1996 B5 8 August 1996 Subsequent to making this adjustment the MWRs were put in TIP mode to check on whether the change in set point temperature affected their calibration. Because clear sky conditions were quite intermittent, it is difficult to determine whether the substantial variability in the tip data were attributable to the change in thermal set point. The instrument calibration was not altered in August. Tip data were again collected with these instruments in September prior to the beginning and at the close of the Water Vapor IOP. For example, the calibration of the instrument at the central facility (S/N 10) derived from the September data was essentially the same as that derived from calibration data acquired in February 1996. Although this would lead one to believe that altering the thermal set point did not affect the instrument calibration, it may be that some transient effect was induced. In comparing soundings launched from the central facility with the microwave radiometer there, I noticed that those sondes calibrated in June 1996 consistently reported lower integrated water vapor than the radiometer in July and September (during the IOP) but were in better agreement with the radiometer for the two weeks period immediately after the set point was adjusted. I suspect that adjusting the thermal set point may have temporarily increased the radiometer gain (kelvins/volt) thereby lowering the measured brightness temperature and the retrieved integrated water vapor. It is not clear why a temporary change in gain should occur or even whether it did. But users of the data should be aware that the data from the microwave radiometers at the SGP may be anomalous during August 1996. |
Measurements: | sgpmwrlosB5.a1:
sgp5mwravgC1.c1:
sgp5mwravgB6.c1:
sgpmwrlosB4.a0:
sgpmwrlosB6.a0:
sgpmwrlosC1.b1:
sgpmwrlosB1.a0:
sgp1mwravgC1.c1:
sgpmwrlosC1.a1:
sgpmwrlosB4.a1:
sgpmwrlosB1.a1:
sgp5mwravgB1.c1:
sgp5mwravgB5.c1:
sgpmwrlosB5.a0:
sgp5mwravgB4.c1:
sgpmwrlosB6.a1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
12/03/1996 | 1937 | 12/12/1996 | 1920 |
Subject: | SGP/MWR/C1 - IRT Calibration check |
DataStreams: | sgpmwrlosC1.a1, sgpmwrlosC1.b1 |
Description: | IRT was out of service for calibration check. MWR was powered down on 96/12/03 1937-1949 to remove IRT and on 96/12/12 1848-1920 to re-install IRT. The following is from the NREL Metrology Laboratory test report of 12/10/97: Temperature Nominal Value Measured Value ----------- ------------- -------------- 0 C 273.2 K 274.1 K 10 283.2 283.6 20 293.2 293.6 30 303.2 303.2 40 313.2 313.2 In the range tested, the temperature difference is within the resolution of the instrument, so the IRT was not adjusted and the calibration factor was not changed. |
Measurements: | sgpmwrlosC1.b1:
sgpmwrlosC1.a1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
05/05/1997 | 0000 | 05/05/1997 | 2359 |
Subject: | SGP/MWR/C1 - IRT Calibration |
DataStreams: | sgpmwrlosC1.a1, sgpmwrlosC1.b1 |
Description: | Comparison of the uplooking IRT with AERI for 5 May 1997 during a time when the 9-11 micrometer sky temperature was in the range 220-228 K, according to AERI, the IRT indicated approximately 3 K higher. This is outside of the specified uncertainty in the IRT and indicates that the calibration needs to be revised. |
Measurements: | sgpmwrlosC1.b1:
sgpmwrlosC1.a1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
09/09/1997 | 1811 | 09/12/1997 | 2037 |
Subject: | SGP/MWR/C1 - IRT offline |
DataStreams: | sgpmwrlosC1.a1, sgpmwrlosC1.b1 |
Description: | The IRT was removed from the MWR to perform a comparison/calibration check prior to the Integrated IOP. |
Measurements: | sgpmwrlosC1.b1:
sgpmwrlosC1.a1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
04/01/1998 | 0000 | 04/30/1998 | 2042 |
Subject: | SGP/MWR/C1 - IRT lens replaced |
DataStreams: | sgpmwrlosC1.a1, sgpmwrlosC1.b1 |
Description: | During my recent trip to the SGP I noticed that the IRT was reading too high (about 250 K for clear sky with less than 2 cm PWV). The anti-reflective coating on the lens appeared to have deteriorated significantly. Because I observed no change in the measurements after cleaning the lens, I replaced it with the original lens which had been saved as a spare. The measured sky temperature fell to 232 K, which appeared more reasonable. The next morning I realized that I had forgotten to clean the lens after replacing it. After cleaning the IR temperature fell from 219 to 213 K with about 1.2 cm PWV. This appeared to be in agreement with Martin Platt's radiometer which measures the same passband (10 micrometers.) Upon returning to Ames, I compared the IRT with AERI for April 1998. It appears that at least as far back as 1 April the IRT data are bad. |
Measurements: | sgpmwrlosC1.b1:
sgpmwrlosC1.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 |
---|---|---|---|
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:
|