| DQR ID | Subject | Data Streams Affected |
|---|---|---|
| D000907.1 | SGP/SIRS/E24 - SIRS Signal Cable Damage at E24 | sgpsirsE24.00, sgpsirsE24.01, sgpsirsE24.a0, sgpsirsE24.a1 |
| D010423.22 | SGP/SIRS/E24 - Diffuse Pyranometer Thermal Offsets | sgpsirsE24.a0, sgpsirsE24.a1 |
| D010423.23 | SGP/SIRS/E25 - Diffuse Pyranometer Thermal Offsets | sgpsirsE25.a0, sgpsirsE25.a1 |
| D021025.1 | SGP/SIRS/E25 Upwelling Longwave Data Out of Range | sgpsirsE25.a0, sgpsirsE25.a1 |
| D990716.31 | SGP/SIRS - SIRS E24 April 1999 | sgpsirsE24.a0, sgpsirsE24.a1 |
| D990716.32 | SGP/SIRS - SIRS E25 April 1999 | sgpsirsE25.a0, sgpsirsE25.a1 |
| Start Date | Start Time | End Date | End Time |
|---|---|---|---|
| 02/08/2000 | 0510 | 02/10/2000 | 1700 |
| Subject: | SGP/SIRS/E24 - SIRS Signal Cable Damage at E24 |
| DataStreams: | sgpsirsE24.00, sgpsirsE24.01, sgpsirsE24.a0, sgpsirsE24.a1 |
| Description: | Cattle from adjoining field had broken the electric fence wire around the equipment and chewed radiometer cables in half adn damaged the shading arm(s) on the SciTec tracker. The NIP and DD shortwave data collected during this time were recorded by the logger as 'over-range' or 'open-channel' (with corresponding data values stored as '-99999') or a numeric value not representative of the real irradiance conditions due to faulty connections. Data for this period are to be considered MISSING. |
| Measurements: | sgpsirsE24.a1:
sgpsirsE24.a0:
sgpsirsE24.00:
sgpsirsE24.01:
|
| Start Date | Start Time | End Date | End Time |
|---|---|---|---|
| 12/03/1997 | 0730 | 02/22/2001 | 1615 |
| Subject: | SGP/SIRS/E24 - Diffuse Pyranometer Thermal Offsets |
| DataStreams: | sgpsirsE24.a0, sgpsirsE24.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: | sgpsirsE24.a1:
sgpsirsE24.a0:
|
| Start Date | Start Time | End Date | End Time |
|---|---|---|---|
| 11/12/1997 | 0226 | 02/21/2001 | 1600 |
| Subject: | SGP/SIRS/E25 - Diffuse Pyranometer Thermal Offsets |
| DataStreams: | sgpsirsE25.a0, sgpsirsE25.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: | sgpsirsE25.a1:
sgpsirsE25.a0:
|
| Start Date | Start Time | End Date | End Time |
|---|---|---|---|
| 03/10/1999 | 0000 | 03/31/2001 | 2359 |
| Subject: | SGP/SIRS/E25 Upwelling Longwave Data Out of Range |
| DataStreams: | sgpsirsE25.a0, sgpsirsE25.a1 |
| Description: | Upwelling longwave irradiance exceeds physical limits. Data are consistently negative and range from -1000 to -2000 W/sq m due to equipment problem(s). |
| Measurements: | sgpsirsE25.a1:
sgpsirsE25.a0:
|
| Start Date | Start Time | End Date | End Time |
|---|---|---|---|
| 04/01/1999 | 0001 | 04/30/1999 | 2359 |
| Subject: | SGP/SIRS - SIRS E24 April 1999 |
| DataStreams: | sgpsirsE24.a0, sgpsirsE24.a1 |
| Description: | Data quality at this site is very good this month. Nearly all 99.6% of the daytime data is present. Passing or low-level flags are assigned to 93.5% of the present daytime data. High level flags seen in the first two days of the month indicate that the DD is above daytime empirical limits. A diurnal plot for the 1st shows that the suntracker has failed: the DD is tracking the DS, and the NIP signal is flat. Low to mid-level flags observed from late morning to mid-afternoon late in the month indicate that the DS is too high by the three-component test. Alternatively, the flags may signal that the NIP or the DD is too low. The DS and DD were forced below daytime or twilight empirical limits by heavy cloud cover on a number of occasions. On the 27th at 1657 GMT the US and UIR signal fields are filled with the data logger value representing missing data - -99999 as if the instruments were disconnected. The Operations Management Information Systems Instrument and Corrective Maintenance Report for this site indicate that the UIR and US were disconnected and the 10m tower taken down for upgrade on the 26th. No problems were noted in the DIR signal. |
| Measurements: | sgpsirsE24.a1:
sgpsirsE24.a0:
|
| Start Date | Start Time | End Date | End Time |
|---|---|---|---|
| 04/01/1999 | 0001 | 04/30/1999 | 2359 |
| Subject: | SGP/SIRS - SIRS E25 April 1999 |
| DataStreams: | sgpsirsE25.a0, sgpsirsE25.a1 |
| Description: | Data quality at this site is very good. All daytime data are present. Passing or low-level flags are assigned to 91.2% of the present daytime data. Another 5.8% of the data are labeled strange-but-true. Low- to mid-level flags in the late afternoon to early evening indicate that the DS is too low by the three-component test. Late in the month overcast skies drove the DS and DD signals below twilight or daytime empirical limits. Shortly after noon on the 14th a possible instance of cloud refraction is recorded in the DS. On the afternoon of the 19th the DS and DD signals fall into the physically impossible region of K-space. The DD signal is recorded as missing (-99999) by the data logger in a few short-lived instances (1-3 in duration minutes each) early in the afternoon of the 25th. Both the UIR and DIR signals continue to be noisy. No problems were noted in the US signal. |
| Measurements: | sgpsirsE25.a1:
sgpsirsE25.a0:
|