NREL's Solar Radiation Research Laboratory performs annual comparisons of Absolute Cavity Radiometers Intercomparisons for transferring the World Radiometric Reference to international, national, and regional researchers. Reference Irradiances, Pictures, and Reports from the following NREL Pyrheliometer Comparisons (NPC) are available:
Reference Irradiance (CSV 15 KB)
Reference Irradiance (CSV 22 KB)
Reference Irradiance (CSV 60 KB) and Report (PDF 1.2 MB)
Reference Irradiance (CSV 112 KB) and Pictures
Reference Irradiance (CSV 79 KB) and Pictures
Reference Irradiance (CSV 81 KB) and Pictures
- Reference Irradiance (CSV 83 KB)
- Picture Set A and Picture Set B
- Report (PDF 32.5 MB)
- Reference Irradiance (CSV 59 KB)
- Pictures
- Report (PDF 6.06 MB)
- Reference Irradiance (CSV 92 KB)
- Pictures
- Info Packet (PDF 586 KB)
- Report (PDF 10.2 MB)
- Reference Irradiance (CSV 96 KB)
- NREL News & Feature Stories
- Pictures Set A and Pictures Set B
- Info Packet (PDF 446 KB)
- Report (PDF 11.2 MB)
- A Tribute to John Hickey (PDF 3.48 MB)
- Reference Irradiance (CSV 55 KB)
- Pictures Set A and Pictures Set B
- Info Packet (PDF 441 KB)
- Report (PDF 4.15 MB)
- Reference Irradiance (CSV 69 KB)
- Pictures Set A and Pictures Set B
- Info Packet (PDF 2.63 MB)
- NPC Report (PDF 2.85 MB)
- ACP/IRIS Report (PDF 603 KB)
- Reference Irradiance (CSV 93 KB)
- Pictures Set A and Pictures Set B
- Info Packet (PDF 426 KB)
- NPC Report (PDF 3.13 MB)
- ACP/IRIS Report (PDF 485 KB)
- Reference Irradiance (CSV 45 KB)
- NPC Report (PDF 685 KB)
- Reference Irradiance (CSV 70 KB)
- Pictures Set A and Pictures Set B
- Info Packet (PDF 893 KB)
- NPC timing and data format (PDF 142 KB)
- NPC Report (PDF 2.3 MB)
- ACP/IRIS Report (PDF 583 KB)
- Reference Irradiance (CSV 129 KB)
- Pictures Set A and Pictures Set B
- Info Packet (PDF 1189 KB)
- NPC timing and data format (PDF 142 KB)
- NPC Report (PDF 3.1 MB)
- ACP/IRIS Report (PDF 838 KB)
- In Memoriam - Dr. Frank Vignola (PDF 178 KB)
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