SunScan User Manual v 1.05
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Local time
- the time used in your particular time zone. It varies from GMT by an
amount depending on longitude, political boundaries, and any daylight saving time.
Mean Leaf Angle
(also Mean Tip Angle, Mean Inclination Angle) is the average
angle of all the leaf elements relative to the horizontal, weighted according to area.
This can be directly related to ELADP.
PAR
- Photosynthetically Active Radiation is visible light of wavelength 400 nm -
700 nm. It is measured in units of
µ
mol.m
-2
.s
-1
(micromoles per square metre per
second) or formerly
µ
E (micro-Einstein). The normal daylight maximum is a little
over 2000
µ
mol.m
-2
.s
-1
.
PAR mapping
- the study of distribution and variation of PAR within and below a
canopy.
PRN
a text file format intended for directly printable output.
Spread
- a measure of the relative variation in light intensity along the SunScan
probe. It is calculated as the Standard Deviation divided by the Mean (sometimes
called coefficient of variation).
SunData software
- the software used to drive the SunScan probe and calculate and
store the results. There are two versions, one which runs in the Psion Workabout, the
other in an IBM compatible PC. They are functionally very similar.
SunScan probe
- the long light sensitive wand and handle used for light readings
within the canopy.
Total PAR
- the sum of Direct beam PAR and the Diffuse light PAR.
Transmission fraction
- the fraction of incident light that passes through a given
canopy. It can refer to Direct, Diffuse, or Total incident light.
Zenith angle
- the angle between the centre of the sun and the point directly
overhead.
