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|
SAM Specifications |
|
|
Quantity |
SAM |
|
Scatterer |
clouds
(and aerosols) |
|
Size Range |
~
5 - 100 µm |
|
OD
range -direct
-indirect |
0
to 10
up to 100 |
|
Minimum aureole angle from disk edge |
~0.25o |
|
Measurement sampling |
~10
sec
(adjustable) |
|
Field
of View |
~50o
(imaging) |
|
OD
measurement accuracy (absolute) |
~0.03 |
|
OD
measurement precision (relative) |
~0.01 |
SAM is a precision solar
tracking instrument that utilizes multiple cameras (filtered
at 670nm) and
a spectrometer to simultaneously measure
the solar aureole caused by forward scattering and the
optical depth of clouds.
|
|
Software:
- The acquired data are processed on-site to deliver
optical depths, aureole profiles and column water vapor
- Automated software is also available from Visidyne for
data validation and analysis, and to produce corrected
optical depths and particle size distributions (effective
particle size)
SAM instrument suites include an integral,
temperature-controlled VIS/NIR Sun spectrometer. It is a CCD
based sensor that uses a Czerny-Turner optical bench. Its
pointing and exposure durations are automatically controlled
by the software, and the instrument electronics has
capability for automatic subtraction of dark pixel values.
Wavelength range = 400 to 950nm
Resolution = 1/3 nm
Dynamic range = 1300:1 for a single acquisition, and >108
for the system
Signal-to-noise = 250:1 at full signal
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