Global Radiation and Aerosols - NOAA Global Monitoring Laboratory
Source: https://gml.noaa.gov/grad/srf.html
Archived: 2026-04-23 17:35
Global Radiation and Aerosols - NOAA Global Monitoring Laboratory
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Global Monitoring Laboratory
Solar Radiation Calibration Facility
Solar Radiation Calibration Facility
Routine Operations
Calibration support for the GML
baseline observatories and the
BSRN
sites
at Kwajalein, Bermuda, and BAO is carried out by the GML Solar Radiation
Calibration Facility (SRCF). Calibrations and characterizations of
pyranometers
and
pyrheliometers
are performed as well
as field exchanges of recalibrated instruments.
Standards Activities
The GML reference
cavity radiometers
were
compared with reference cavities from other organizations during 1994 and
1995. A cavity intercomparison was held at the National Renewable Energy Laboratory
in Golden, Colorado, October 8- 10, 1994. In 1995 the GML references were
taken to the World Radiation Center in Davos, Switzerland, for participation
in the
WMO
sponsored eighth International
Pyrheliometer Comparison (IPCVIII). These comparisons are typically conducted
every 5 years and allow reference instruments from all of the WMO regions
to document their performance relative to a standard group of instruments
maintained at the World Radiation Center. Participation of the GML reference
cavities (TM167502 and AHF28553) in IPCVIII maintains the historical traceability
of the NOAA standards to the World Radiometric Reference maintained in Davos
and the World Radiation Center. All solar radiation measurements made by GML
are thus traceable to the world reference.
SRCF was designated as the WMO/CIMO Region IV National Radiometric Calibration Center for the US in the late 1970s and has carried out the related tasks since that time.
Instrument Development Activities
Solar tracking accuracy at field sites has been improved by implemention
of a more accurate solar position algorithm in the tracker control program,
precision leveling of the solar tracker during installation and setup, and
the addition of a solar position detector designed and built by GML to the
solar tracker. Tracking accuracies of better than 0.1 degrees are achievable
with these improvements. In addition, software was added to the tracker control
computer that allows remote access to the tracker control program via modem.
This capability, together with the solar position detector data, will allow
monitoring of tracker performance at the remote sites and tracker control
from Boulder if necessary. Installation of a new
Eppley
automated self-calibrating cavity radiometer system in the refurbished MLO
solar dome was also completed during the latter part of 1995. Continuous direct-solar-
beam data is now available in addition to the NIP data that have been collected
since 1958.
Special Projects
In addition to the routine GML monitoring support for the four baseline
observatories. The SRCF provides support, resources, training, and logistics
assistance in other areas such as the World Meteorological Organization/Global
Environmental Fund/ Global Atmospheric Watch
(WMO/GEF/
GAW
)
baseline station network.
Skip to main content
An official website of the United States government
Here's how you know
Official websites use .gov
A
.gov
website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or
https://
means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.
Global Monitoring Laboratory
Solar Radiation Calibration Facility
Solar Radiation Calibration Facility
Routine Operations
Calibration support for the GML
baseline observatories and the
BSRN
sites
at Kwajalein, Bermuda, and BAO is carried out by the GML Solar Radiation
Calibration Facility (SRCF). Calibrations and characterizations of
pyranometers
and
pyrheliometers
are performed as well
as field exchanges of recalibrated instruments.
Standards Activities
The GML reference
cavity radiometers
were
compared with reference cavities from other organizations during 1994 and
1995. A cavity intercomparison was held at the National Renewable Energy Laboratory
in Golden, Colorado, October 8- 10, 1994. In 1995 the GML references were
taken to the World Radiation Center in Davos, Switzerland, for participation
in the
WMO
sponsored eighth International
Pyrheliometer Comparison (IPCVIII). These comparisons are typically conducted
every 5 years and allow reference instruments from all of the WMO regions
to document their performance relative to a standard group of instruments
maintained at the World Radiation Center. Participation of the GML reference
cavities (TM167502 and AHF28553) in IPCVIII maintains the historical traceability
of the NOAA standards to the World Radiometric Reference maintained in Davos
and the World Radiation Center. All solar radiation measurements made by GML
are thus traceable to the world reference.
SRCF was designated as the WMO/CIMO Region IV National Radiometric Calibration Center for the US in the late 1970s and has carried out the related tasks since that time.
Instrument Development Activities
Solar tracking accuracy at field sites has been improved by implemention
of a more accurate solar position algorithm in the tracker control program,
precision leveling of the solar tracker during installation and setup, and
the addition of a solar position detector designed and built by GML to the
solar tracker. Tracking accuracies of better than 0.1 degrees are achievable
with these improvements. In addition, software was added to the tracker control
computer that allows remote access to the tracker control program via modem.
This capability, together with the solar position detector data, will allow
monitoring of tracker performance at the remote sites and tracker control
from Boulder if necessary. Installation of a new
Eppley
automated self-calibrating cavity radiometer system in the refurbished MLO
solar dome was also completed during the latter part of 1995. Continuous direct-solar-
beam data is now available in addition to the NIP data that have been collected
since 1958.
Special Projects
In addition to the routine GML monitoring support for the four baseline
observatories. The SRCF provides support, resources, training, and logistics
assistance in other areas such as the World Meteorological Organization/Global
Environmental Fund/ Global Atmospheric Watch
(WMO/GEF/
GAW
)
baseline station network.