FED/MAC Data
Pyranometer Data Sets
Measurements of hemispherical downwelling solar
irradiance and hemispherical upwelling reflected
radiance from the forest canopy were taken with
pyranometers (0.3 to 3.0 micron) mounted on the tower
in the Northern Experimental Forest in Howland, Maine.
Both upward and downward viewing Eppley PSP pyranometers
were mounted on a boom extending 2.4 meters west from
the tower's topmost rail, which is about 25.8 meters
above the ground level. The pyranometer instantaneous
output voltages were recorded in digital form at 59
second intervals on an automatic data logger. The
pyranometers used in this study were intercalibrated
against a reference instrument by exposing all
instruments upward on a clear, cloudless day. Calibration
coefficients were then computed the instruments so
that radiances were equal to the reference instrument
values. The instrument that was used as the reference
instrument was calibrated at the Eppley Laboratory in
November 1989.
Data Available:
Measurements taken by:
Don Deering
NASA/GSFC
Biospheric Sciences Branch, Code 923
Greenbelt, MD 20771
Tom Eck
NASA/GSFC
Biospheric Sciences Branch, Code 923
Greenbelt, MD 20771