REBS Radiation and Soil Sensors
Q*7
HFT
Introduction
Net radiometers are used to determine the total net radiation (sum of
visible and infrared; difference between incoming and outgoing) near the
Earth's surface.
We use the Model Q*7 made by REBS (Radiation and Energy Balance Systems, Inc.).
They have two calibration coefficients -- one for positive
values (generally daytime, dominated by visible radiation) and another,
smaller, value for negative values (nighttime, infrared). ISFF also routinely
measures all 4 of these radiation components at up to 4 locations individually
with pyranometers and pyrgeometers, but usually still uses net radiometers for
redundancy.
In the Q7 manual provided by Campbell Scientific, there is a correction for convective
cooling as a function of wind speed, that we often apply.
ISFF also uses the REBS heat flux plates (HFT) and soil temperature
sensors to determine the heat flux into, and heat storage by, the top layer
of soil.
These sensors are used to determine components of the total surface energy
balance.
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