В журнале Reviews of Geophysics была напечатана обзорная статья по состоянию климата Антарктики и Южного океана (State of the Antarctic and Southern Ocean climate system). В подготовке статьи принимали участие многие видные исследователи Антарктики.
Статья доступна по запросу на нашем форуме.
State of the Antarctic and Southern Ocean climate system
State of the Antarctic and Southern Ocean climate system
P. A. Mayewski
Climate Change Institute, University of Maine, Orono, Maine, USA
M. P. Meredith
British Antarctic Survey, Cambridge, UK
C. P. Summerhayes
Scientific Committee for Antarctic Research, Cambridge, UK
J. Turner
British Antarctic Survey, Cambridge, UK
A. Worby
Australian Antarctic Division and Antarctic Climate and Ecosystems Cooperative Research Centre, University of Tasmania, Hobart,
Tasmania, Australia
P. J. Barrett
Antarctic Research Centre, Victoria University of Wellington, Wellington, New Zealand
G. Casassa
Glaciology and Climate Change Laboratory, Centro de Estudios Científicos, Valdivia, Chile
N. A. N. Bertler
Climate Change Institute, University of Maine, Orono, Maine, USA
Antarctic Research Centre, Victoria University of Wellington, Wellington, New Zealand
T. Bracegirdle
British Antarctic Survey, Cambridge, UK
A. C. Naveira Garabato
School of Ocean and Earth Science, University of Southampton, Southampton, UK
D. Bromwich
Byrd Polar Research Center, Ohio State University, Columbus, Ohio, USA
H. Campbell
British Antarctic Survey, Cambridge, UK
G. S. Hamilton
Climate Change Institute, University of Maine, Orono, Maine, USA
W. B. Lyons
Byrd Polar Research Center, Ohio State University, Columbus, Ohio, USA
K. A. Maasch
Climate Change Institute, University of Maine, Orono, Maine, USA
S. Aoki
Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan
C. Xiao
China Meteorological Administration, Beijing, China
Tas van Ommen
Australian Antarctic Division and Antarctic Climate and Ecosystems Cooperative Research Centre, University of Tasmania, Hobart,
Tasmania, Australia
This
paper reviews developments in our understanding of the state of the
Antarctic and Southern Ocean climate and its relation to the global
climate system over the last few millennia. Climate over this and
earlier periods has not been stable, as evidenced by the occurrence of
abrupt changes in atmospheric circulation and temperature recorded in
Antarctic ice core proxies for past climate. Two of the most prominent
abrupt climate change events are characterized by intensification of
the circumpolar westerlies (also known as the Southern Annular Mode)
between ∼6000 and 5000 years ago and since 1200–1000 years ago.
Following the last of these is a period of major trans-Antarctic
reorganization of atmospheric circulation and temperature between A.D.
1700 and 1850. The two earlier Antarctic abrupt climate change events
appear linked to but predate by several centuries even more abrupt
climate change in the North Atlantic, and the end of the more recent
event is coincident with reorganization of atmospheric circulation in
the North Pacific. Improved understanding of such events and of the
associations between abrupt climate change events recorded in both
hemispheres is critical to predicting the impact and timing of future
abrupt climate change events potentially forced by anthropogenic
changes in greenhouse gases and aerosols. Special attention is given to
the climate of the past 200 years, which was recorded by a network of
recently available shallow firn cores, and to that of the past 50
years, which was monitored by the continuous instrumental record.
Significant regional climate changes have taken place in the Antarctic
during the past 50 years. Atmospheric temperatures have increased
markedly over the Antarctic Peninsula, linked to nearby ocean warming
and intensification of the circumpolar westerlies. Glaciers are
retreating on the peninsula, in Patagonia, on the sub-Antarctic
islands, and in West Antarctica adjacent to the peninsula. The
penetration of marine air masses has become more pronounced over parts
of West Antarctica. Above the surface, the Antarctic troposphere has
warmed during winter while the stratosphere has cooled year-round. The
upper kilometer of the circumpolar Southern Ocean has warmed, Antarctic
Bottom Water across a wide sector off East Antarctica has freshened,
and the densest bottom water in the Weddell Sea has warmed. In contrast
to these regional climate changes, over most of Antarctica,
near-surface temperature and snowfall have not increased significantly
during at least the past 50 years, and proxy data suggest that the
atmospheric circulation over the interior has remained in a similar
state for at least the past 200 years. Furthermore, the total sea ice
cover around Antarctica has exhibited no significant overall change
since reliable satellite monitoring began in the late 1970s, despite
large but compensating regional changes. The inhomogeneity of Antarctic
climate in space and time implies that recent Antarctic climate changes
are due on the one hand to a combination of strong multidecadal
variability and anthropogenic effects and, as demonstrated by the
paleoclimate record, on the other hand to multidecadal to millennial
scale and longer natural variability forced through changes in orbital
insolation, greenhouse gases, solar variability, ice dynamics, and
aerosols. Model projections suggest that over the 21st century the
Antarctic interior will warm by 3.4° ± 1°C, and sea ice extent will
decrease by ∼30%. Ice sheet models are not yet adequate enough to
answer pressing questions about the effect of projected warming on mass
balance and sea level. Considering the potentially major impacts of a
warming climate on Antarctica, vigorous efforts are needed to better
understand all aspects of the highly coupled Antarctic climate system
as well as its influence on the Earth's climate and oceans.
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