INTRODUCTION
Solar radiation at Earth’s surface is typically defined as total radiation across a wavelength range of 280 to 4000
nm (shortwave radiation). Total solar radiation, direct beam and diffuse, incident on a horizontal surface is defined
as global shortwave radiation, or shortwave irradiance (incident radiant flux), and is expressed in Watts per square
meter (W m
-2
, equal to Joules per second per square meter).
Pyranometers are sensors that measure global shortwave radiation.
Larson Electronics
solar radiation meters
incorporate silicon-cell pyranometers, and are only sensitive to a portion of the solar spectrum, approximately
350-1100 nm (approximately 80 % of total shortwave radiation is within this range). However, silicon-cell
pyranometers are calibrated to estimate total shortwave radiation across the entire solar spectrum. Silicon-cell
pyranometer specifications compare favorably to specifications for World Meteorological Organization (WMO)
moderate and good quality classifications and specifications for International Organization of Standardization (ISO)
second class and first class classifications, but because of limited spectral sensitivity, they do not meet the spectral
specification necessary for WMO or ISO certification.
Typical applications of silicon-cell pyranometers include incoming shortwave radiation measurement in
agricultural, ecological, hydrological weather networks, and solar panel arrays.
Larson Electronics
series solar radiation meters consist of a handheld meter and a dedicated pyranometer that is
integrated into the top of the meter housing or connected by cable to an anodized aluminum housing. Integrated
and separate sensors consist of a cast acrylic diffuser (filter), photodiode, and are potted solid with no internal air
space.
These
meters provide a real-time irradiance reading on the LCD display that determines the radiation
incident on a planar surface (does not have to be horizontal), where the radiation emanates from all angles of a
hemisphere.
Larson Electronics solar radiation
meters include manual and automatic data logging features for
making spot-check measurements or calculating daily solar insolation.
Larson Electronics, LLC
Phone: (800) 369-6671
Fax: (903) 498-3364
www.larsonelectronics.com
