DQR ID | Subject | Data Streams Affected |
---|---|---|
D010423.10 | SGP/SIRS/E9 - Diffuse Pyranometer Thermal Offsets | sgpsirsE9.a0, sgpsirsE9.a1 |
D010423.8 | SGP/SIRS/E7 - Diffuse Pyranometer Thermal Offsets | sgpsirsE7.a0, sgpsirsE7.a1 |
D010423.9 | SGP/SIRS/E8 - Diffuse Pyranometer Thermal Offsets | sgpsirsE8.a0, sgpsirsE8.a1 |
D010430.11 | SGP/SIRS/E7 - Tracking Problems | sgpsirsE7.a1 |
D020619.2 | SGP/SIRS/E7 - April 1999 Quality Review | sgpsirsE7.a0, sgpsirsE7.a1 |
D020909.3 | SGP/SIRS/E8 - Solar Tracker Failure | sgpsirsE8.a1 |
D031124.2 | SGP/SIRS/E8 - | sgpsirsE8.a0, sgpsirsE8.a1 |
D031124.3 | SGP/SIRS/E9 - | sgpsirsE9.a0, sgpsirsE9.a1 |
D970927.1 | SIRS NIPs affected by condensation at E8, E11, E13, & E15 | sgpsirsE8.a1, sgpsirsE11.a1, sgpsirsE13.a1, sgpsirsE15.a1 |
D990716.11 | SGP/SIRS - SIRS E7 April 1999 (part 2 of 3) | sgpsirsE7.a0, sgpsirsE7.a1 |
D990716.13 | SGP/SIRS - SIRS E8 April 1999 (SERI-QC Results) | sgpsirsE8.a0, sgpsirsE8.a1 |
D990716.14 | SGP/SIRS - SIRS E9 April 1999 (SERI-QC Results) | sgpsirsE9.a0, sgpsirsE9.a1 |
Start Date | Start Time | End Date | End Time |
---|---|---|---|
02/07/1998 | 0215 | 02/13/2001 | 1540 |
Subject: | SGP/SIRS/E9 - Diffuse Pyranometer Thermal Offsets |
DataStreams: | sgpsirsE9.a0, sgpsirsE9.a1 |
Description: | Broadband downwelling shortwave diffuse (sky) irradiance measurements available from SIRS during the period of this Data Quality Report (DQR), require adjustment for thermal offsets. These thermal, or ?zero? offsets refer to the generally reduced output signals from a shaded pyranometer due to the exchange of longwave (infrared) irradiance between the single black thermopile detector, the protective glass domes surrounding the detector, and the atmosphere. Originally considered an acceptable nighttime response of thermopile-type pyranometers, the generally negative bias is now recognized to significantly effect the accuracy of SIRS diffuse irradiance data during daylight periods. Studies of the Eppley Laboratory, Inc. Model PSP (Precision Spectral Pyranometer), used for the SIRS measurements of diffuse irradiance, suggest the thermal offset correction can range from near 0 to as much as 30 Watts per square meter, depending on the coincident net longwave, or infrared irradiance [1, 2]. Under very clear-sky conditions, the diffuse irradiance from a shaded PSP can be less than the minimum physical limit defined by radiative transfer model estimates based only on Rayleigh scattering effects. A correction method has been developed for adjusting SIRS diffuse irradiance data [3]. The resulting Value Added Product (VAP) will be applied to SIRS data for the period of this DQR. The VAP will not be applied to SIROS data collected before the instrument platform was converted to SIRS. Additionally, the Model PSP radiometer has been replaced by a Model 8-48 which uses a black and white thermopile detector known to reduce the thermal offset errors to less than 2 Watts per square meter [3]. The radiometer replacement at this SIRS location was completed on the ending date of this DQR. References: 1. Gulbrandsen, A., 1978: On the use of pyranometers in the study of spectral solar radiation and atmospheric aerosols. J. Appl. Meteorol., 17, 899-904. 2. Cess, R. D., X. Jing, T. Qian, and M. Sun, 1999: Validation strategies applied to the measurement of total, direct and diffuse shortwave radiation at the surface. J. Geophys. Res. 3. Dutton, E.G., J. Michalsky, T. Stoffel, B. Forgan, J. Hickey, D. Nelson, T. Alberta, and I. Reda, 2001: Measurement of Broadband Diffuse Solar Irradiance Using Current Commercial Instrumentation With a Correction for Thermal Offset Errors. J. Atmos. Oceanic Tech. Vol 18, No. 3, 297-314. (March 2001) |
Measurements: | sgpsirsE9.a1:
sgpsirsE9.a0:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
10/31/1997 | 0227 | 02/13/2001 | 1925 |
Subject: | SGP/SIRS/E7 - Diffuse Pyranometer Thermal Offsets |
DataStreams: | sgpsirsE7.a0, sgpsirsE7.a1 |
Description: | Broadband downwelling shortwave diffuse (sky) irradiance measurements available from SIRS during the period of this Data Quality Report (DQR), require adjustment for thermal offsets. These thermal, or ?zero? offsets refer to the generally reduced output signals from a shaded pyranometer due to the exchange of longwave (infrared) irradiance between the single black thermopile detector, the protective glass domes surrounding the detector, and the atmosphere. Originally considered an acceptable nighttime response of thermopile-type pyranometers, the generally negative bias is now recognized to significantly effect the accuracy of SIRS diffuse irradiance data during daylight periods. Studies of the Eppley Laboratory, Inc. Model PSP (Precision Spectral Pyranometer), used for the SIRS measurements of diffuse irradiance, suggest the thermal offset correction can range from near 0 to as much as 30 Watts per square meter, depending on the coincident net longwave, or infrared irradiance [1, 2]. Under very clear-sky conditions, the diffuse irradiance from a shaded PSP can be less than the minimum physical limit defined by radiative transfer model estimates based only on Rayleigh scattering effects. A correction method has been developed for adjusting SIRS diffuse irradiance data [3]. The resulting Value Added Product (VAP) will be applied to SIRS data for the period of this DQR. The VAP will not be applied to SIROS data collected before the instrument platform was converted to SIRS. Additionally, the Model PSP radiometer has been replaced by a Model 8-48 which uses a black and white thermopile detector known to reduce the thermal offset errors to less than 2 Watts per square meter [3]. The radiometer replacement at this SIRS location was completed on the ending date of this DQR. References: 1. Gulbrandsen, A., 1978: On the use of pyranometers in the study of spectral solar radiation and atmospheric aerosols. J. Appl. Meteorol., 17, 899-904. 2. Cess, R. D., X. Jing, T. Qian, and M. Sun, 1999: Validation strategies applied to the measurement of total, direct and diffuse shortwave radiation at the surface. J. Geophys. Res. 3. Dutton, E.G., J. Michalsky, T. Stoffel, B. Forgan, J. Hickey, D. Nelson, T. Alberta, and I. Reda, 2001: Measurement of Broadband Diffuse Solar Irradiance Using Current Commercial Instrumentation With a Correction for Thermal Offset Errors. J. Atmos. Oceanic Tech. Vol 18, No. 3, 297-314. (March 2001) |
Measurements: | sgpsirsE7.a1:
sgpsirsE7.a0:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
08/21/1997 | 0700 | 02/13/2001 | 1815 |
Subject: | SGP/SIRS/E8 - Diffuse Pyranometer Thermal Offsets |
DataStreams: | sgpsirsE8.a0, sgpsirsE8.a1 |
Description: | Broadband downwelling shortwave diffuse (sky) irradiance measurements available from SIRS during the period of this Data Quality Report (DQR), require adjustment for thermal offsets. These thermal, or ?zero? offsets refer to the generally reduced output signals from a shaded pyranometer due to the exchange of longwave (infrared) irradiance between the single black thermopile detector, the protective glass domes surrounding the detector, and the atmosphere. Originally considered an acceptable nighttime response of thermopile-type pyranometers, the generally negative bias is now recognized to significantly effect the accuracy of SIRS diffuse irradiance data during daylight periods. Studies of the Eppley Laboratory, Inc. Model PSP (Precision Spectral Pyranometer), used for the SIRS measurements of diffuse irradiance, suggest the thermal offset correction can range from near 0 to as much as 30 Watts per square meter, depending on the coincident net longwave, or infrared irradiance [1, 2]. Under very clear-sky conditions, the diffuse irradiance from a shaded PSP can be less than the minimum physical limit defined by radiative transfer model estimates based only on Rayleigh scattering effects. A correction method has been developed for adjusting SIRS diffuse irradiance data [3]. The resulting Value Added Product (VAP) will be applied to SIRS data for the period of this DQR. The VAP will not be applied to SIROS data collected before the instrument platform was converted to SIRS. Additionally, the Model PSP radiometer has been replaced by a Model 8-48 which uses a black and white thermopile detector known to reduce the thermal offset errors to less than 2 Watts per square meter [3]. The radiometer replacement at this SIRS location was completed on the ending date of this DQR. References: 1. Gulbrandsen, A., 1978: On the use of pyranometers in the study of spectral solar radiation and atmospheric aerosols. J. Appl. Meteorol., 17, 899-904. 2. Cess, R. D., X. Jing, T. Qian, and M. Sun, 1999: Validation strategies applied to the measurement of total, direct and diffuse shortwave radiation at the surface. J. Geophys. Res. 3. Dutton, E.G., J. Michalsky, T. Stoffel, B. Forgan, J. Hickey, D. Nelson, T. Alberta, and I. Reda, 2001: Measurement of Broadband Diffuse Solar Irradiance Using Current Commercial Instrumentation With a Correction for Thermal Offset Errors. J. Atmos. Oceanic Tech. Vol 18, No. 3, 297-314. (March 2001) |
Measurements: | sgpsirsE8.a0:
sgpsirsE8.a1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
09/10/2000 | 0000 | 10/10/2000 | 2359 |
Subject: | SGP/SIRS/E7 - Tracking Problems |
DataStreams: | sgpsirsE7.a1 |
Description: | Nip off the solar disk, diffuse has become completely unshaded, per Karen Sonntag. |
Measurements: | sgpsirsE7.a1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
04/01/1999 | 0000 | 04/08/1999 | 1500 |
04/09/1999 | 1801 | 04/30/1999 | 2359 |
Subject: | SGP/SIRS/E7 - April 1999 Quality Review |
DataStreams: | sgpsirsE7.a0, sgpsirsE7.a1 |
Description: | Data quality is good at this site this month with just under 96% of the daytime data present. Passing or low-level flags are assigned to 96.1% of the present daytime data. |
Measurements: | sgpsirsE7.a1:
sgpsirsE7.a0:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
03/18/2000 | 0000 | 06/20/2000 | 1700 |
Subject: | SGP/SIRS/E8 - Solar Tracker Failure |
DataStreams: | sgpsirsE8.a1 |
Description: | Downwelling Diffuse values too high and Direct Normal values too low. Diffuse pyranometer not shaded due to tracker failure. Direct Normal pyrheliometer not properly aligned with the solar disc due to tracker failure. (These radiometers are mounted on the same solar tracker.) |
Measurements: | sgpsirsE8.a1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
01/01/2000 | 0000 | 02/01/2000 | 0000 |
Subject: | SGP/SIRS/E8 - |
DataStreams: | sgpsirsE8.a0, sgpsirsE8.a1 |
Description: | Data quality this month is OK. The noteable problems follow. Nighttime offsets in the Downwelling pyranometer (DS) average about -5 W/m^2 for the month. The Downwelling Diffuse pyranometer (DD) averages about -6 W/m^2 for its nighttime offset. There are inconsistencies between the Global (DS), Direct (NIP) and Diffuse (DD) components for the 4th, 6th and 7th in the afternoon and the 1st, 2nd, 4th, 5th, 7th, 9th, 11th, 15th, 19th, and 20th in the morning. These inconsistencies range in severity from mild to substansial even though they all trigger yellow flags only (or stay green). In every case the DD and NIP are responsivity for all solar zenith angles, or the switchover from daylight to twilight testing regimes. The daytime negative offset in the DS PSP is also a probable factor in the error. It should also be noted that the calibration factors for the PSP's have a tolerance of plus or minus 5% and the NIP has a tolerance of plus or minus 3%. Upwelling Longwave goes below empirical limits on the 4th from 12:25 to 13:25 GMT, the 29th from 13:00 to 15:20 GMT and on the 31st from 05:15 to 06:30 GMT. The winter Longwave empirical limit of 250 W/m^2 is currently under further review. (A reading of 250 W/m^2 suggests a temperature between 5 and 20 degrees Fahrenheit.) DD goes below nighttime empirical limits on the local night of the 1st intermittently for a total of about an hour and a half. DS and DD go daytime empirical limits on the 4th and 7th. Finally, the two longwave components are conducted to make a conjecture for possible failure. Upwelling Shortwave (US) goes below its nighttime empirical limit after sunset on the local nights of the 5th, 12th, and the 15th. The duration is substantial on the 12th. Something happens on the 27th and 29th where US exceeds its daytime empircal limit. Snowy conditions is a possible cause. |
Measurements: | sgpsirsE8.a0:
sgpsirsE8.a1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
01/01/2000 | 0000 | 02/01/2000 | 0000 |
Subject: | SGP/SIRS/E9 - |
DataStreams: | sgpsirsE9.a0, sgpsirsE9.a1 |
Description: | Data quality this site- month is excellent. In fact, there are only unnoteworthy and insignificant problems from the 8th thru the end of the month. Nighttime offsets for the Global (DS) and Diffuse (DD) pyranometers are -7 W/m^2 a piece. DS and DD dip below their daytime empirical limits on the 3rd and 8th. Both days DS is under the limit for under an hour and a half inconsistencies between the Global (DS), Direct (NIP) and Diffuse (DD) components for the mornings of the 4th and 5th. NIP exceeds its daytime empirical limit on the 7th for about 20 minutes. Longwave looks good by automated testing and visual inspection. |
Measurements: | sgpsirsE9.a1:
sgpsirsE9.a0:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
09/26/1997 | 1230 | 09/26/1997 | 1330 |
09/26/1997 | 1230 | 09/26/1997 | 1345 |
09/26/1997 | 1230 | 09/26/1997 | 1415 |
Subject: | SIRS NIPs affected by condensation at E8, E11, E13, & E15 |
DataStreams: | sgpsirsE8.a1, sgpsirsE11.a1, sgpsirsE13.a1, sgpsirsE15.a1 |
Description: | Comparison of data from the unshaded PSP to that derived from the 'direct + diffuse' (NIP + shaded PSP) indicated low values of the 'direct+diffuse' combination starting at sunrise and lasting for about an hour at E8, E11, E13 and E15. Futher examination revealed that the NIPs were reading low and were likely affected by condensation during this brief period. Weather conditions were foggy over the area early that morning, and fog quickly dissipated after sunrise. |
Measurements: | sgpsirsE15.a1:
sgpsirsE11.a1:
sgpsirsE8.a1:
sgpsirsE13.a1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
04/08/1999 | 1501 | 04/09/1999 | 1800 |
Subject: | SGP/SIRS - SIRS E7 April 1999 (part 2 of 3) |
DataStreams: | sgpsirsE7.a0, sgpsirsE7.a1 |
Description: | **Times are Local Standard** Data are missing during this period. |
Measurements: | sgpsirsE7.a1:
sgpsirsE7.a0:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
04/01/1999 | 0001 | 04/30/1999 | 2359 |
Subject: | SGP/SIRS - SIRS E8 April 1999 (SERI-QC Results) |
DataStreams: | sgpsirsE8.a0, sgpsirsE8.a1 |
Description: | Data quality for this site is very good this month. All data are present, and 95.5% of the present daytime data are assigned passing or low-level flags. Low-level flags seen mid-day into early afternoon on clear or partly cloudy days indicate that the DS is too high by the three-component test. Alternatively, the DD or NIP may be too low. Strange-but-true flags can be seen mid-day on cloudy and overcast. Shortly after sunrise on the 22nd the DS and DD were forced below twilight empirical limits by overcast conditions. Shortly after noon on the 26th the DS was higher than daytime empirical limits for a short time, possibly a case of sunlight reflecting from the edge of a cloud onto the radiometer. No problems noted in the UIR, DIR or US signals. |
Measurements: | sgpsirsE8.a0:
sgpsirsE8.a1:
|
Start Date | Start Time | End Date | End Time |
---|---|---|---|
04/01/1999 | 0001 | 04/30/1999 | 2359 |
Subject: | SGP/SIRS - SIRS E9 April 1999 (SERI-QC Results) |
DataStreams: | sgpsirsE9.a0, sgpsirsE9.a1 |
Description: | Data quality for this site is very good this month. All data are present, and 88% of the present daytime data earns passing or low-level flags. This would be higher but for the large number of strange-but-true flags, many of them occurring between the 23rd and 27th. Overcast skies forced the DS and DD below the appropriate empirical limits on a number of afternoons. Late on the 2nd both the DS and the DD were forced above twilight empirical limits. Low-level flags seen shortly after sunrise on clear or partly cloudy days indicate that the DS is too low, or that the DD or NIP is too high by the three-component test. The NIP fell below daytime empirical limits around noon on the 22nd. |
Measurements: | sgpsirsE9.a1:
sgpsirsE9.a0:
|