Re: [Phys-l] Antarctic Ice Shelf Falling Apart

[marx@phy.ilstu.edu]

Is an an article about the Antarctic Peninsula and the observed rapid warming, which is in contrast to
what is happening elsewhere on the continent (see below).
http://www.antarctica.ac.uk/bas_research/our_research/topics/climate_change/our_world/antarctic_pe
ninsula.php

The Arctic and Antarctic Ice Area has been monitored since 1978-9.  While there has been a
decreasing ice area in the Artctic, there has been a positive trend toward increased ice area throughout
this period for Antarctica.

Here is a link to relevant data, which is updated on a daily basis:
http://arctic.atmos.uiuc.edu/cryosphere/

Additional Info.

Antarctica has 70% of all the world's freshwater frozen as ice - and 90% of all the world's ice.
Mean Thickness
1,829 m / 6,000 ft
Mean thickness East Antarctica:
2,226 m / 7,300 ft
Mean thickness West Antarctica:
1,306 m / 4,285 ft
Maximum ice thickness:
4,776 m / 15,670ft

Coldest Temp:
-129°F (-89°C) on July 21, 1983
Location: Vostok Station
Warmest Temp:
+59°F (+15°C) on Jan 5, 1974
Location: Vanda Station
Mean Temps:
Winter: -40 to -94°F (-40 to -70°C)
Summer: -5 to -31°F (-15 to -35°C)

Temperature Studies:
Chapman, W.L. and Walsh, J.E. 2007. A synthesis of Antarctic temperatures. Journal of Climate 20:
4096-4117.
Temperatures over land were obtained from 19 manned stations of the World Monthly Surface Station
Climatology network, most of which were located in coastal areas of the Antarctic continent, plus 73
stations of the Automated Weather Station network, many of which were situated further inland.
Temperatures over the sea were obtained from the International Comprehensive Ocean-Atmosphere
Data repository. Of particular importance in their melding of these diverse data, the authors used
correlation length scaling "to enhance information content while limiting the spatial extent of influence
of the sparse data in the Antarctic region.  Between 1958 and 1970, there was a slight warming period
of about 0.4 C, but the average temperature has remained fairly constant since then.

Josefino C. Comiso, Journal of Climate, Volume 13, Issue 10, 1674-1696 (May 2000)
The surface air temperatures observed from stations in Antarctica have been shown to have
predominantly positive trends that are as high as 0.5°C decade-1 along the Antarctic Peninsula. To
evaluate whether the trends are caused by a local or large-scale phenomenon in the Antarctic region,
surface temperatures inferred from infrared satellite data from 1979 to 1998 have been analyzed in
combination with data from 21 stations that have long record lengths. The surface temperatures
derived from infrared data are coherent spatially and temporally and are shown to agree well with
Antarctic station data with a correlation coefficient of 0.98 and a standard deviation of about 3°C. The
trend analysis on station data yielded on the average 0.012 ± 0.008°C yr-1 and -0.008 ± 0.025°C yr-1
for the 45- and 20-yr record, respectively. The latter reasonably agrees with the trend of -0.042 ±
0.067°C yr-1 inferred from the satellite 20-yr record. The 20-yr record length is shown to be about the
minimum length required for a meaningful trend analysis study. However, interannual fluctuations of
the temperatures are large and the 95% confidence level for the satellite trends ranges from -0.177 to
0.094°C yr-1 for the Antarctic ice sheet.

Nature 415, 517-520 (31 January 2002)
"Climate models generally predict amplified warming in polar regions3, 4, as observed in Antarctica's
peninsula region over the second half of the 20th century5, 6, 7, 8, 9. Although previous reports
suggest slight recent continental warming9, 10, our spatial analysis of Antarctic meteorological data
demonstrates a net cooling on the Antarctic continent between 1966 and 2000, particularly during
summer and autumn. The McMurdo Dry Valleys have cooled by 0.7 °C per decade between 1986 and
2000, with similar pronounced seasonal trends. Summer cooling is particularly important to Antarctic
terrestrial ecosystems that are poised at the interface of ice and water. Here we present data from the
dry valleys representing evidence of rapid terrestrial ecosystem response to climate cooling in
Antarctica, including decreased primary productivity of lakes (6-9% per year) and declining numbers of
soil invertebrates (more than 10% per year). Continental Antarctic cooling, especially the seasonality of
cooling, poses challenges to models of climate and ecosystem change."


On 30 Apr 2009 at 7:44, Spinozalens@aol.com wrote:

> Average temperatures in the Antarctic Peninsula have  risen by 3.8 degrees
> Fahrenheit over the past 50 years - higher than the average  global rise,
> according to studies.
> Over the next several weeks, scientists estimate the  Wilkins shelf will
> lose some 1,300 square miles - a piece larger than the state  of Rhode Island,
> or two-thirds the size of Luxembourg.
>
> _http://news.aol.com/article/antarctic-ice-shelf-falling-apart/452969?icid=m