International Polar Year 2007–2008 - WMO

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IPY 20 07–20 08
base Syowa via the deep drilling sites at Kohnen and
at Dome Fuji. Data collected included radar soundings
for ice depth and snow layering, air sampling,
snow sampling for chemical analyses, snow sampling
for physical property measurements, snow pit studies
for snow sampling, firn coring for various analyses
and 10 m temperature, weather observations, GPSmeasurements
and ground truth surveys for satellite
data. The traverse enabled extensive ground truth
sampling of physical snow properties such as snow
grain size. Snow grain size is determined by moisture
content and air temperature, and shows decreasing
size towards the center of Antarctica and larger grains
in the coastal areas. The grain size and shape results
are correlated with coincident and historical satellite
data including SAR imagery from ENVISAT ASAR,
QuikSCAT scatterometry and optical-thermal satellite
data (MERIS & MODIS) over the study area. Preliminary
results indicate that the black carbon content in air
and snow over the Antarctic plateau is higher than expected.
The concentration in air is higher than found
near the coast, and the content in snow is about 10
times larger than used in published climate simulations,
albeit with large spatial variations. Subglacial
landforms that may be relicts from the initiation of the
Antarctic glaciation about 30 million years ago were
described and continuous measurements of aerosols,
bed topography, ice layering, snow layering and surface
topography were measured en route.
The Norwegian-U.S. Scientific Traverse of East
Antarctica completed two seasons (2007 and
2008/2009) of overland traverses of East Antarctica
beginning at the Norwegian Troll Station, following an
ice divide to the South Pole and returning to Troll by
a route over the Recovery Subglacial Lakes. The main
research focus of the program was to examine climate
variability in Dronning Maud Land, East Antarctica
on time scales of years to a 1000 years by a series of
shallow cores, firn studies and temperature profiles.
The team has been able to establish spatial and
temporal variability in snow accumulation over this
area of Antarctic both through ice cores and linking
the surface based studies to satellite measurements.
Results from new ice cores are providing new
constraints on the accumulation in East Antarctica for
the past 2000 years. Analysis of the surface radar has
enabled a robust relationship between the surface
and space observations. Detailed snow pits enable
new insights into the impact of atmospheric and
oceanic variability on the chemical composition of firn
and ice in the region. The physical properties of snow
and firn, from crystal structure to mesoscale strata
morphology, reveal a complicated East Antarctic
climate history. Five 90 m-long in situ thermal profiles
obtained from automated, satellite-uplinked stations
provide an independent, new assessment of climate
trends in the remotest parts of Antarctica.
d. Change
The planners of IPY envisioned that programs
targeted at Change in the Polar Regions would seek
to quantify, and understand, past and present natural
environmental change in the polar regions, and to
improve projections of future change. IPY 2007–2008
programs addressing change covered the spectrum of
past change through present change to projections of
future change.
The existing Antarctic Climate Evolution (ACE,
www.ace.scar.org) activity, a Scientific Research Project
(SRP) of the Scientific Committee on Antarctic
Research (SCAR) emerged as a core IPY project and
was an umbrella for many smaller projects fitting beneath.
ACE’s mission is to facilitate the study of Antarctic
climate and glacial history through integration
of numerical modeling with geophysical and geological
data. The overall goal of ACE is to facilitate those
model-data interactions for better understanding of
Antarctic climate and ice sheet variability over the full
range of Cenozoic (last ~65 million years) timescales.
Over the last five years, ACE has made major contributions
to the understanding of the early development
of the Antarctic Ice Sheet in the Oligocene and
its variability through the Miocene. Much of this work
has led to a new appreciation for the importance of atmospheric
greenhouse gas concentrations relative to
other potential forcing mechanisms (e.g. orbital forcing,
ocean circulation, etc.) in controlling the onset of
glaciation and magnitude of subsequent ice volume
variability.
A direct outcome of ACE was the ANDRILL project
that included a major drilling field campaign integrated
with a numerical modeling effort. During IPY, ANDRILL
completed its first two seasons of sedimentary drilling
in the Ross Sea. The drilling effort recovered over 2400