Introduction
The goals of this
project are to educate students about noctilucent clouds (NLCs)
and involve them in NLC observations. The
project will provide
guest lectures, tutorials on the
internet, and prepare teachers
to continue this education. Students
will observe NLCs using local and remote digital
cameras. Images
from these cameras will be posted here for public viewing.
Relevant Links
From Pekka Parviainen of Finland
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Noctilucent
Clouds and Climate Change
Noctilucent clouds
(NLCs), otherwise known as polar mesospheric clouds (PMCs), form near
82 km altitude at high latitudes during summer in both hemispheres,
and can be viewed with the naked
eye .
When viewed from the ground, NLCs
appear in reflected sunlight against
the dark twilight sky. These sightings
can be brilliant, leading ground-based
observers to call them noctilucent or ”night-shining” clouds. NLCs consist
of tiny water ice particles, and
thus are controlled
by temperature and humidity. Mesospheric temperature and humidity
respond to changes in CO2 and CH4
, gases that are increasing due to human activity. As a result, NLCs are one of the few
visible indicators of global
climate change, and indeed evidence shows that NLC
patterns are
changing. An analysis of over 25 years of satellite measurements shows that
NLC occurence frequencies are increasing by about 8% every 10 years
[Shettle et al., 2002]. Historically, NLCs have only been viewed at latitudes between
50 ° to 65 ° (in both
hemispheres). In
recent years, however, NLCs have been sighted at
mid-latitudes
for the first time. A recent
report in
the Journal
of Geophysical Research [Wickwar et al.,
2002] describes NLCs over Logan, Utah, that were viewed
with the naked eye, photographed, and measured by lidar
("light detection and ranging"). Changes in NLC
patterns
have sparked an increase in the awareness of these clouds, and
motivate an increased effort to understand these clouds and what they
tell us about our environment.
References
Shettle, E. P., Thomas, G.E., Olivero, J.J., Evans, W.F.J., Debrestian,
D.J., Chardon, L., 2002. Three-satellite comparison of polar mesospheric
clouds: Evidence for long-term change. Journal of Geophysical Research,
107(D12), 4134, doi:10.1029/2001JD000668.
Wickwar, V. B., M. J. Taylor, J. P. Herron, and B. A.
Martineau, Visual and lidar observations of noctilucent clouds
above Logan, Utah, at 41.7N, J. Geophys. Res.,
10.1029/2001JD001180, 2002.
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Lesson Materials
This
project offers a variety of lessons covering topics relevant the
atmosphere, climate, and NLCs. These Powerpoint lessons
target general audiences and are designed to be 1 hour presentations.
This program is funded
by NASA's Office of Space Science.
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The principal
investigator is
Mark Hervig of GATS Inc.
Our primary partner is
Bret Graves at Teton High School in Driggs, Idaho.
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