March 17, 1999
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Editor: Cheryl Dybus
Contents of this News Tip:
Researchers at the Universities of Massachusetts and Arizona who study
global warming have released a report strongly suggesting that the 1990s
were the warmest decade of the millennium, with 1998 the warmest year
so far. The scientists have also found that the warming in the 20th century
counters a 1,000-year-long cooling trend.
The study, by Michael Mann and Raymond Bradley of the University of
Massachusetts and Malcolm Hughes of the University of Arizona, appears
in the March 15 issue of Geophysical Research Letters, published
by the American Geophysical Union. The research was supported in part
by the National Science Foundation (NSF).
"Temperatures in the latter half of the 20th century were unprecedented," said
Bradley. The study involved a close examination of natural archives, such
as tree rings and ice cores, which record climate variations each year.
These natural archives are called "proxy indicators" by scientists. They
allow researchers to consider the short instrumental record of climate
in a longer-term perspective. Using proxy information gathered by scientists
around the world during the past few decades, the team used sophisticated
computer analysis and statistics to reconstruct yearly temperatures and
their statistical uncertainties, going back to the year AD 1000.
"As you go back farther in time, the data become sketchier. One can't
quite pin things down as well," noted Mann, "but, our results do reveal
that significant changes have occurred, and temperatures in the latter
20th century have been exceptionally warm compared to the preceding 900
years." [Cheryl Dybas]
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How much do sulfate aerosols -- a form of pollution -- cool the climate?
That's one of the most pressing questions for understanding global climate
change. To help find the answer, the National Center for Atmospheric Research
(NCAR) has sent researchers, instruments, and an NSF-owned C-130 research
aircraft to the $25-million Indian Ocean Experiment (INDOEX). NSF is NCAR's
primary sponsor and a partial sponsor of INDOEX.
INDOEX is based in the Republic of the Maldives, an archipelago southwest
of India's southern tip. There, NCAR scientists are working alongside
more than 70 researchers from a dozen nations to observe the tropical
oceans and atmosphere. The highly instrumented C-130 aircraft will be
based through March 27 at Male airport, which occupies its own island
in the archipelago.
The Indian subcontinent and surrounding nations are rich sources for
many kinds of aerosols, including those produced from industrial and auto
emissions, biomass burning, and soil dust. With Asia's population rising
at a dramatic rate, the amount of sulfur dioxide released into the atmosphere
is expected to increase. Sulfur dioxide is converted into sulfate aerosol
in the atmosphere. The ability of sulfate aerosols to reflect the sun's
radiation may be one reason that increasing greenhouse gases have not
warmed the earth as much as some climate models have predicted. Sulfates
also contribute to local pollution and acid rain.
According to NCAR's Jeffrey Kiehl, a principal investigator for INDOEX,
Pollution in the tropics will increase in the future, "so we'd better
understand it now. The chemistry in the tropics is severely undersampled." [Cheryl
Dybas]
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A $2-million NSF grant has made it possible for Purdue University's
Schools of Veterinary Medicine, Science and Education to generate a fun,
cutting-edge interactive computer program called BioScope to help high
school students learn biology. The program uses the Internet and makes
biology a learning experience with the characteristics of a video game.
Purdue researchers have incorporated music and electronic sounds, as
well as animations and video, into this educational tool. This CD-based
system is designed for automatic updates. Each time the student signs
onto the program's computer, the software updates BioScope's web paths
and links. Because the site can be constantly changed, students' interest
is maintained in part by the site's everchanging look.
BioScope is based on light microscope images that lead to other images
from electron microscopy, laser confocal microscopy, fluorescence microscopy
and laser flow cytometry. The goal is to use these microscope and research
technologies -- considered the "bedrock" of experimental biological research
-- to provide teachers and students with non-textbook-based biology images
that better reflect the current status of cell biology knowledge. BioScope
uses the talents of active research scientists to produce materials for
the program. [Lee Herring] Top of Page
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