BEN # 174
aceska at CUE.BC.CA
Mon Oct 27 02:19:20 EST 1997
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No. 174 October 26, 1997
aceska at freenet.victoria.bc.ca Victoria, B.C.
Dr. A. Ceska, P.O.Box 8546, Victoria, B.C. Canada V8W 3S2
BOTANY BC - AS IT HAPPENED IN AUGUST 1997
From: Del Meidinger <Del.Meidinger at gems2.gov.bc.ca>
BOTANY BC was held at Cathedral Park on the 1-2 August 1997. It
was well attended and the sessions, both inside and outside,
proved to be excellent. The staff of the Conservation Data
Centre, especially Jan Kirkby, did an outstanding job of or-
ganizing the program, facilities, and tour guides. It will
definitely live on in the memories of those who attended as one
of the best BOTANY BC meetings.
The official program began with an evening of interesting
presentations by staff of the CDC (although many of us were able
to fit in an afternoon hike and plant identification tour). The
presentations were well presented and received. Hans' slides of
plants of the Alps were incredible. The next day involved a long
hike along the ridge trail with George Douglas and Hans Roemer
pointing out the plants along the trail. The evening concluded
with one of the best Botany Boogie's ever (thanks to Andy MacK-
innon and all others around the fire).
BOTANY BC is still the best botanical meeting in BC and it has
the added attraction of being every year! See you next year in
the Peace River area.
IS IT EL NINO OR PACIFIC DECADAL OSCILLATION ?
[This News Release was originally posted on ECOLOG-L.]
It looks like El Nino, it feels like El Nino, and if you are
watching fish stocks, reservoir levels or farm production, you
would say it is El Nino. But it isn't.
Researchers at the University of Washington are describing in
two recent research papers what they call a decades-long climate
shift in the Pacific Ocean that seems to explain many of the
changing environmental patterns seen across North America, and
particularly in the Pacific Northwest, since the late 1970s.
The scientists are calling this climatic phenomenon the PDO, for
Pacific decadal oscillation. And, they say, its current positive
cycle helps to explain why U.S. West Coast ocean temperatures
have been warmer than average, why winters have been wetter than
usual in the South, and why Alaska salmon harvests have been at
historic highs, while there have been record declines along the
El Nino, it appears, is only one small -- albeit exaggerated --
phase of this cycle, says David Battisti, UW atmospheric
sciences associate professor, who was the first to show why El
Nino recurs on an average of every four years. He describes this
latest discovery as an index of sea-surface temperatures in the
North Pacific, "which my guess also involves the tropics." Says
Battisti: "This phenomenon explains much about what is happening
in regional climate change. And if we could predict the PDO, we
would have much more reliable forecasts."
However, says Nate Mantua, a UW research associate, scientists
probably will not have the ability to begin making accurate
forecasts for at least another five years. A PDO prediction
system, he says, would allow long-term planning in such areas as
fisheries, water supplies, agriculture and energy production.
"The science right now is more like our understanding of El Nino
15 to 20 years ago," says Mantua. But when a PDO forecast is
developed, he says, it will become an important measure of
climate across North America.
The discovery of the PDO has been something of a scientific
detective story. Using high-speed computers, researchers combed
the past century's meteorological records to see if they could
spot any recurring patterns of climate change. In more recent
decades, El Nino quickly emerged as the dominant recurring
pattern of year-to-year climate variability on the planet. But
when records were studied back to 1900, with the focus on the
region north of Hawaii in the Pacific basin, the PDO revealed
itself with positive and negative phases lasting from 10 to 30
With a few interruptions, researchers found that since 1977 the
PDO has been in a positive phase with cool air in the Southeas-
tern U.S., and a tendency to dry weather over the Columbia Basin
and the Great Lakes. In the Northwest, winters have been largely
warm and dry, water levels have been down because there have
been fewer storms than normal, and snow packs have been low. In
the previous negative phase of the PDO, lasting from 1947 to
1976, the Northwest's water supplies were an average of 20
percent higher than between the 1920s and the 1940s, with more
precipitation and higher snow packs.
Evidence also suggests that many populations of Pacific salmon
are influenced by changes in marine climate. This could explain
why in the last negative phase of the PDO, when coastal ocean
temperatures were cooler, coho and chinook salmon were in abun-
dance off the coasts of Washington, Oregon and California, but
Alaska's stocks were greatly depleted. Since the 1970s, warmer
coastal waters have reversed these conditions. However, the UW
researchers say, the present positive phase of the PDO should be
expected to reverse within a decade, at which time favorable
ocean conditions should return for West Coast salmon.
Many of these climate changes are felt across North America
because of wave patterns -- like ripples in a stream -- in the
atmosphere, which is directly affected by changes of temperature
in Pacific Ocean currents. But the phenomenon is particularly
evident in the Northwest because of a feature in the wind field
called the Aleutian low, which directs atmospheric patterns
across the region.
One of the puzzles of the PDO, says Mantua, is whether it acts
as a restraint on El Nino, or whether it is a long-term response
to the phenomenon. Mantua says he prefers the argument that the
PDO is a slower change in the climate system of the oceans and
atmosphere over the entire Pacific basin which influences how El
One frustrating aspect of attempting to forecast the PDO is that
it develops over such a long period that a negative or a posi-
tive phase can have passed before researchers even discover it.
"We can recognize the phenomenon, but we can't say what phase
we're in at the time," says Battisti. "But that's only because
we don't yet fully understand it. After all, it has only been in
recent years that we've recognized it even exists."
To find out what the PDO forecast could be for your region, call
Battisti at (206) 543-2019 --- <david at atmos.washington.edu>, or
call Mantua at (206) 616-5347 --- <mantua at atmos.washington.edu>.
Mantua, N.J. and S.R. Hare, Y. Zhang, J.M. Wallace, and R.C.
Francis. 1997. A Pacific interdecadal climate oscillation
with impacts on salmon production. Bulletin of the American
Meteorological Society 78(6): 1069-1079.
Full article is accessible at:
Zhang, Y., J.M. Wallace and D.S. Battisti. 1997. ENSO-like
Decade-to-Century Scale Variability: 1900-93. J. Climate 10:
The abstract is at:
Note: See also Steven Hare's bibliography page at:
/decadal/decadal.html [this should be all on one line]
GOOD NEWS FROM THE CANADA MUSEUM OF NATURE
From: Irwin Brodo <ibrodo at mus-nature.ca> originally posted on
lichens-l at hawaii.edu [abbreviated]
I am happy to report that the Canadian Museum of Nature has just
signed a contract with Yale University Press for the production
of "Lichens of North America," and as a result, I have been
given permission to resume work on the book. Many of you will
recall that the work was halted, first in early October 1996 and
then, after I was given the go-ahead in November, again in
December pending the signing of the contract.
[BEN # 148 (November 2, 1996) paid some attention to this mat-
ter. - AC]
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