26
SYSTEM
Flared hole
Tipping
spoon
Gold
electrodes
Downspout
& screen
Figure 12 ATMOS 41W interior
3.2.1 PYRANOMETER (SOLAR RADIATION)
Solar radiation is measured by a pyranometer embedded in the lip of the rain gauge funnel
at the top of the ATMOS 41W. Designed, manufactured, and calibrated by experts at Apogee
Instruments, Inc., the miniature pyranometer uses a silicon-cell sensor to measure the
total incoming (direct and diffuse) solar radiation. A carefully developed cosine-correcting
head ensures accurate readings regardless of sun angle, while the painstakingly researched
optical filter material balances cost and performance to ensure the silicon-cell provides
good accuracy regardless of temperature or sensor age. Silicon-cell sensors have excellent
response time to changing radiation conditions and acceptable sensitivity across the solar
spectrum (
), which make them perfect for use on the ATMOS 41W.
