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Physikalisch-Meteorologisches Observatorium Davos (PMOD), World Radiation Center (WRC), Switzerland

PFR is part of a small network run by PMOD WRC on behalf of the World Meteorological Organization (WMO).

What does this program measure?

The program measures solar spectral irradiance, atmospheric transmission, and aerosol optical depth. The units of measurement are relative, rsp. (a dimensionless quantity)

USDA Ultraviolet Solar Instruments on MLO Sun Deck (courtesy of Forest M. Mims III)
Solar Sensors at MLO sunset (courtesy of Forrest M. Mims III)

How does this program work?

By passive remote sensing of atmospheric transmission using the Sun as a standard light source.

Why is this research important?

Atmospheric turbidity or Aerosol Optical Depth (AOD) is a crucial parameter in understanding the radiative forcing of Earth's climate and a core parameter in the World Meteorological Organization (WMO) Global Atmosphere Watch monitoring program.

Are there any trends in the data?

No trends have been established yet.

How does this program fit into the big picture?

What is it's role in global climate change?

Aerosols exert a predominantly cooling effect on climate. Their optical properties in the atmospheric column are summarized by AOD.

Comments and References

Mauna Loa Observatory is a prime calibration site for WMO/GAW PFR network

Lead Investigator(s):

Christoph Wehrli
+41 (0)81 417 51 37

MLO Contact(s):

Paul Fukumura
808-933-6965 (x223)

Web Site(s)

Date Started


Related Programs

Solar Radiation
Air Quality Control


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