A new level 2 (c2/s2) release for the Data Quality Assessment for ARM Radiation Data (QCRAD) value-added product (VAP) is now available. This release covers the following 13 extended facilities at the Atmospheric Radiation Measurement (ARM) user facility’s Southern Great Plains atmospheric observatory:
- E9 (Ashton, Kansas) from June 3, 2016, to August 25, 2019
- E11 (Byron, Oklahoma) from June 18, 2017, to August 1, 2019
- E12 (Pawhuska, Oklahoma) from June 15, 2017, to August 26, 2019
- E15 (Ringwood, Oklahoma) from June 21, 2017, to August 20, 2019
- E21 (Okmulgee, Oklahoma) from July 21, 2017, to May 22, 2018
- E31 (Anthony, Kansas) from May 30, 2018, to July 28, 2019
- E34 (Maple City, Kansas) from July 24, 2018, to July 21, 2019
- E36 (Marshall, Oklahoma) from July 21, 2016, to June 25, 2019
- E37 (Waukomis, Oklahoma) from July 20, 2016, to June 21, 2019
- E38 (Omega, Oklahoma) from August 3, 2018, to July 26, 2019
- E39 (Morrison, Oklahoma) from August 1, 2018, to September 4, 2019
- E40 (Pawnee, Oklahoma) from August 1, 2018, to July 23, 2019
- E41 (Peckham, Oklahoma) from July 14, 2017, to June 18, 2019.
QCRAD has long been ARM’s recommended datastream for broadband surface irradiance measurements. The QCRAD methodology uses climatological analyses of the surface radiation measurements to define reasonable limits for testing the data for unusual values. QCRAD applies multiple data quality checks, corrects for errors due to infrared loss in shortwave (SW) radiometric measurements, and calculates a best-estimate total downwelling SW irradiance value.
The QCRAD VAP produces two daily files containing 1-minute radiation measurement fields and their quality control (QC) values. The *.c1 file—the asterisk represents the datastream name—includes auxiliary information and detailed qc flags. The *.s1 summary file includes a simplified version of the qc flags and fewer auxiliary data values.
During operational processing, the QCRAD VAP applies a generic correction to the downwelling SW hemispheric flux to correct for infrared loss within the radiometer. This processing produces the .c1 and .s1, or level 1, datastreams.
On a yearly basis, the VAP applies a more detailed correction using infrared loss corrections derived for the specific instruments, rather than the generic correction. This processing produces .c2 and .s2, or level 2, datastreams. This correction will affect the output of the downwelling SW values when the sum of the direct plus diffuse SW is not available as the best estimate for downwelling SW. When *.c2 and *.s2 files are available, they should be used.
Read this article announcing an earlier QCRAD release for Southern Great Plains extended facilities.
Scientists can use the new QCRAD data now. Yearly processing for remaining ARM fixed sites will follow.
Please note: Use E9 shortwave and longwave broadband downwelling irradiance data near the sunset horizon with caution. A nearby windmill will shade the instruments near sunset.
To share your experience with QCRAD—such as how you use the data and how well they work for you—or to ask a question, contact Josh Howie.
To cite the QCRAD data, please use the following DOIs:
- qcrad1long.c2 datastreams: 10.5439/1227214
- qcradbrs1long.c2 datastreams: 10.5439/1227217
- qcradbeflux1long.c2 datastreams: 10.5439/1227218.
ARM is a DOE Office of Science user facility operated by nine DOE national laboratories.