The fossil history of plant life in Antarctica is central to our understanding of the evolution of vegetation through geological time and also plays a key role in reconstructing past configurations ...of the continents and associated climatic conditions. This book provides the only detailed overview of the development of Antarctic vegetation from the Devonian period to the present day, presenting Earth scientists with valuable insights into the break up of the ancient supercontinent of Gondwana. Details of specific floras and ecosystems are provided within the context of changing geological, geographical and environmental conditions, alongside comparisons with contemporaneous and modern ecosystems. The authors demonstrate how palaeobotany contributes to our understanding of the palaeoenvironmental changes in the southern hemisphere during this period of Earth history. The book is a complete and up-to-date reference for researchers and students in Antarctic palaeobotany and terrestrial palaeoecology.
The target is the non-secular, non-seasonal, interannual ice-mass redistribution over the Antarctica continent, as observed by the satellite mission GRACE (Gravity Recovery and Climate Experiment) ...for the period from 2002 to 2016. We employ the empirical orthogonal function (EOF) and complex EOF (CEOF) methods on the GRACE monthly time-variable gravity in the form of the mascon data. We find three separate phenomena on different timescales that are hitherto unreported: (i) EOF Mode 1 represents an interannual standing “seesaw” pattern largely concentrates along the coast, which we refer to as the Antarctica Coastal Dipole (ACD), with turnarounds coincident with ENSO events, relative to precipitation anomalies, whereas Mode 2-3 both correlate with the Antarctica Oscillation (AAO); (ii) the leading CEOF Mode shows two different propagating waves, one is the Eastward Propagation (EP) with the periodicity of ∼4.7 years most evident in the East Antarctica, may be induced by the Antarctica Circumpolar Wave; (iii) another is a Westward Propagation (WP) with ∼2 years periodicity in the West Antarctica that mainly travels from the Ronnie Ice Shelf to the Ross Ice Shelf, may relate to AAO.
•EOF and CEOF solve for interannual Antarctica ice-mass variations.•Leading EOF Mode is an Antarctica Coastal Dipole influenced by ENSO events.•EOF Modes 2-3 correlate with Antarctic Oscillation.•CEOF shows a 4.7-year Eastward Propagation and a 2-year Westward Propagation.
The Technocratic Antarcticis an ethnographic account of the scientists and policymakers who work on Antarctica. In a place with no indigenous people, Antarctic scientists and policymakers use ...expertise as their primary model of governance. Scientific research and policymaking are practices that inform each other, and the Antarctic environment-with its striking beauty, dramatic human and animal lives, and specter of global climate change-not only informs science and policy but also lends Antarctic environmentalism a particularly technocratic patina.
Jessica O'Reilly conducted most of her research for this book in New Zealand, home of the "Antarctic Gateway" city of Christchurch, and on an expedition to Windless Bight, Antarctica, with the New Zealand Antarctic Program. O'Reilly also follows the journeys Antarctic scientists and policymakers take to temporarily "Antarctic" places such as science conferences, policy workshops, and the international Antarctic Treaty meetings in Scotland, Australia, and India. Competing claims of nationalism, scientific disciplines, field experiences, and personal relationships among Antarctic environmental managers disrupt the idea of a utopian epistemic community. O'Reilly focuses on what emerges in Antarctica among the complicated and hybrid forms of science, sociality, politics, and national membership found there.The Technocratic Antarcticunfolds the historical, political, and moral contexts that shape experiences of and decisions about the Antarctic environment.
We examine data continuity between the Gravity Recovery and Climate Experiment (GRACE) and GRACE Follow‐On (FO) missions over Greenland and Antarctica using independent data from the mass budget ...method, which calculates the difference between ice sheet surface mass balance and ice discharge at the periphery. For both ice sheets, we find consistent GRACE/GRACE‐FO time series across the data gap, at the continental and regional scales, and the data gap is confidently filled with mass budget method data. In Greenland, the GRACE‐FO data reveal an exceptional summer loss of 600 Gt in 2019 following two cold summers. In Antarctica, ongoing high mass losses in the Amundsen Sea Embayment of West Antarctica, the Antarctic Peninsula, and Wilkes Land in East Antarctica cumulate to 2130, 560, and 370 Gt, respectively, since 2002. A cumulative mass gain of 980 Gt in Queen Maud Land since 2009, however, led to a pause in the acceleration in mass loss from Antarctica after 2016.
Key Points
We demonstrate data continuity of the GRACE and GRACE‐FO missions over Greenland and Antarctica using independent data
GRACE‐FO data capture a record‐high summer loss (600 Gt) in Greenland in 2019
Mass gain in Queen Maud Land mitigate high losses in the Amundsen Sea, Peninsula, and Wilkes Land to pause the acceleration in mass loss
Polar Cousins Leuprecht, Christian; Causey, Douglas
2022, Letnik:
29
eBook
Odprti dostop
Geopolitics and climate change now have immediate consequences for national and international security interests across the Arctic and Antarctic. The world’s polar regions are contested and ...strategically central to geopolitical rivalry. At the same time, rapid political, social, and environmental change presents unprecedented challenges for governance, environmental protection, and maritime operations in the regions. With chapters that raise awareness, address challenges, and inform policy options, Polar Cousins reviews the state of strategic thinking and options on Antarctica and the Southern Oceans in light of experience in the circumpolar North. Prioritizing strategic issues, it provides an essential discussion of geostrategic thinking, strategic policy, and strategy development. Featuring contributions from international defence experts, scientists, academics, policymakers, and decisionmakers, Polar Cousins offers key insights into the challenges unique to the polar regions.
Winter owns most of the year at the South Pole, starting in
mid-February and ending in early November. Total darkness lasts for
months, temperatures can drop below -100 degrees Fahrenheit, and
...windchill can push temperatures to -140 degrees. At those
temperatures a person not protected with specialized clothing and
an understanding of how to wear it would be reduced to an icicle
within minutes. Few people on the planet can say they know what it
feels like to walk in the unworldly, frigid winter darkness at the
South Pole, but Wayne L. White can-having walked several thousand
miles and never missing a day outside during his stay, regardless
of the conditions. As the winter site manager of the Amundsen-Scott
South Pole Station in Antarctica, White was responsible for the
selection, training, and health and safety of the forty-two- and
forty-six-person crews. Motivated by the determination and bravery
of historical pioneers such as Roald Amundsen, Robert Falcon Scott,
and Ernest Shackleton, White honed his leadership skills to guide a
diverse group of experienced and talented craftsmen, scientists,
and artisans through three winters, the longest term of any winter
manager. Despite hardships, disasters, and watching helpless as a
global pandemic unfolded far beyond their horizon, his crews
prevailed. In Cold White documents his time in these
extreme elements and offers a unique perspective on the United
States Antarctic Program at the South Pole.
Antarctic paleotemperatures
It has been widely thought that East Antarctica was ∼9°C cooler during the Last Glacial Maximum, close to the ∼10°C difference between then and now determined ...independently for West Antarctica. Buizert
et al.
used borehole thermometry, firn density reconstructions, and climate modeling to show that the temperature in East Antarctica was actually only ∼4° to 7°C cooler during the Last Glacial Maximum. This result has important consequences for our understanding of Antarctic climate, polar amplification, and global climate change.
Science
, abd2897, this issue p.
1097
East Antarctica temperature increased since the Last Glacial Maximum by only about half of previous estimates.
Water-stable isotopes in polar ice cores are a widely used temperature proxy in paleoclimate reconstruction, yet calibration remains challenging in East Antarctica. Here, we reconstruct the magnitude and spatial pattern of Last Glacial Maximum surface cooling in Antarctica using borehole thermometry and firn properties in seven ice cores. West Antarctic sites cooled ~10°C relative to the preindustrial period. East Antarctic sites show a range from ~4° to ~7°C cooling, which is consistent with the results of global climate models when the effects of topographic changes indicated with ice core air-content data are included, but less than those indicated with the use of water-stable isotopes calibrated against modern spatial gradients. An altered Antarctic temperature inversion during the glacial reconciles our estimates with water-isotope observations.
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