[ TERC VHS-1 Sun Photometer ] [ Manual TOC ]
There are many ways to modify the TERC VHS-1. Just be sure
that the diameter of the sunlight port and its distance from the
LED have the same dimensions as those given in this manual.
It's okay to use a Radio Shack printed circuit board instead
of a solderless breadboard. But you will need to solder the parts
and wires to the board. It's also possible to use a smaller
switch with solder, instead of screw, terminals. Soldering is
easy if you know what to do. See "Getting Started in Electronics"
(Radio Shack, 1983) for simple soldering instructions and
information about electronic parts such as the operational
amplifier, LED and resistor used in the TERC VHS-1.
Finally, the solderless breadboard inside the TERC VHS-1 has
room for up to two additional amplifiers and LEDs. This means you
can expand the instrument to measure other wavelengths of light
by using different LEDs. You will need to provide a way to select
which amplifier is connected to the voltmeter.
Many articles on haze have been published in magazines. See,
for example, "Lost Horizons" by Stephen F. Corfidi (Weatherwise,
12-17, June/July 1993); "The Parasol Effect" by David Berreby
(Discover, 44-50, July 1993); and "Haze Clouds the Greenhouse" by
Richard Monastersky (Science News, 141, 232-233, April 11, 1992).
Hundreds of papers on haze and its measurement have been
published in scientific journals. An especially good general
paper is "Haze and Sulfur Emission Trends in the Eastern United
States" by Rudolf B. Husar and William E. Wilson (Environmental
Science Technology, 27, 1, 12-16, 1993).
Astronomer Robert G. Roosen has specialized in interpreting
old Sun photometer data collected by the Astrophysical
Observatory of the Smithsonian Institution at various sites
around the world from the early part of this century until the
1960's. See, for example, Dr. Roosen's classic paper, written
with Ronald J. Angione and Clara H. Klemcke, "Worldwide
Variations in Atmospheric Transmission: 1. Baseline Results from
Smithsonian Observations" (Bulletin of the American
Meteorological Society, 54, 4, 307-316, 1973).
An excellent reference on haze in the United States is
"Acidic Deposition: State of Science and Technology, Report 24,
Visibility: Existing and Historical Conditions--Causes and
Effects," John C. Trijonis et al., U. S. Government Printing
How Sun photometers on the ground are used to verify Sun
photometers in satellites is described by G. S. Kent, M. P.
McCormick and P. -H. Wang in "Validation of Stratospheric Aerosol
and Gas Experiments I and II satellite aerosol optical depth
measurements using surface radiometer data (Journal of
Geophysical Research, 99, D5, 10,333-10,340, 1994).
You can find more articles on haze by looking under the
keyword "haze" in various reference indexes at a library.
For more information on finding the local apparent time for
your location, see The USA Today Weather Almanac (Vintage
Books, 1995). You can also find information on this subject in
basic books about astronomy and sun dials.
At the time of this writing, there is very little
information about haze on the Internet. Hopefully, your data will
someday appear there!