SAFARI
2000: The Southern African Regional Science Initiative Fires
routinely scorch the Southern African landscape at this time of year, blackening
an area larger than Montana, Wyoming, Idaho, North Dakota and South Dakota combined.
But this year's burning season, which reaches its peak this month, could be nearly
twice as big as usual, according to researchers taking part in a NASA-supported
field experiment studying the impact of these fires on global climate and the
region's air quality and ecosystems. SAFARI
2000, the Southern African Regional Science Initiative, brings together nearly
200 African, U.S., and international scientists in a multidisciplinary research
effort aimed at understanding the sustainability of the region's sensitive and
pressured ecosystems. An intensive six-week field experiment began on August 13
combining observations from NASA's Terra and Landsat 7 spacecraft, NASA's ER-2
high-altitude research aircraft, and several other aircraft and ground stations.
The base of operations is in Pietersburg, South Africa. SAFARI
2000 coincides with Southern Africa's dry season, the time of the most extensive
biomass burning. The region is subject to some of the highest levels of biomass
burning in the world. "This
will be a humdinger of a season," says ecologist Robert Scholes of the South African
research organization CSIR Environmentek and one of the organizers of SAFARI 2000.
Heavy rains earlier this year in southeastern Africa caused extensive flooding
in Mozambique and spurred the growth of more plant biomass, says Scholes, which
results in more plant fuel to burn in the current dry season. Scholes,
noting that heavy fires followed a similar wet year in 1994, predicts that as
much as twice the average acreage could burn this season. Grass-fueled fires burn
rapidly and do little damage to mature trees. August
and September are the peak months for fires in most of Southern Africa. In an
average year, nearly 500,000 square miles of grasslands burns in Africa south
of the equator. The region's heaviest burning is concentrated in the moist subtropical
belt that includes Angola, the southern Congo, Zambia, northern Mozambique, and
southern Tanzania. In
addition to observations of the fires and smoke from space, SAFARI 2000 researchers
are using an arsenal of airborne and ground-based scientific instruments to sample
the chemistry and measure the thickness of the smoke plumes, map the movements
of large plumes, and investigate how smoke and other fine particles affect clouds.
The collective data will be used to improve the ability of new instruments on
Terra to monitor active fires, map "burn scars" left after the fires, and measure
the amount of carbon monoxide in the lower atmosphere. SAFARI
2000 planners track the changing location of fires with daily satellite maps provided
by researchers at NASA's Goddard Space Flight Center. At several times during
the field experiment, preplanned fires in protected areas such as game reserves
are set to coincide with spacecraft passes over the region. Aircraft flights are
also coordinated with these burns so that detailed measurements can be made of
the fire and smoke plume. Fire
management practices are a subject of much debate in Southern Africa, as they
are in the United States, says Scholes. But in Africa fire is considered less
of a disaster and more of a natural and necessary part of healthy ecosystem functioning.
Fire
management policies in South Africa's largest game reserve, Kruger National Park,
have changed over the years from a ban on all fires to a systematic cycle of controlled
burns over the entire park. Both practices resulted in unwanted changes to ecosystems
and losses of biodiversity, says Scholes. As a result, Kruger instituted a new
policy in the mid-1990s of fighting all man-made fires and allowing all natural
fires (those ignited by lightning) to burn uncontrolled. It's
not yet clear, says Scholes, whether the benefits to the ecosystem of this new
approach will outweigh the danger of allowing the load of plant fuel on the ground
to accumulate. "If you don't keep the fuel load down, you can get yourself into
a fire trap, like parts of California have done recently, where there is so much
fuel on the ground that you're stuck," Scholes believes. Madikwe
Game Reserve in northern South Africa has adopted a different experimental approach.
Small areas of the reserve's grasslands are intentionally burned on a schedule
designed by computers to mimic the natural cycles and patterns of fires. One such
controlled burn of 250 acres in Madikwe was set on the morning of August 20 to
coincide with SAFARI 2000 research activities. Less
than 20 percent of Southern African fires are controlled fires like these, Scholes
estimates. NASA's Earth Observing System Project, a suite of spacecraft and interdisciplinary
science investigations dedicated to advancing our knowledge of global change,
is the primary sponsor of U.S. participants in SAFARI 2000.
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Image
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Ecologist
Dr. Robert Scholes of the South African research organization CSIR Environmentek
at an instrumented tower site in Kruger National Park, South Africa. Scholes is
one of the organizers of the SAFARI 2000 field campaign.
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Image
2 | | A
small prescribed grassland fire on August 15, 2000 in Kruger National Park, South
Africa, set to coincide with the overpass of NASA's Terra spacecraft and research
aircraft involved in the SAFARI 2000 field campaign. Back
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