Found 14065 items
1 November, 2011 by Mark Clilverd
Observed phases and amplitudes of VLF radio signals propagating on very long paths are used to validate electron density parameters for the lowest edge of the (D region of the)…Read more on Daytime D region parameters from long-path VLF phase and amplitude
1 November, 2011 by Angelika Renner, Sally Thorpe
We present observations of high-frequency current variability on the continental shelf and the slope of the Antarctic Peninsula using Lagrangian surface drifters deployed as part of the Antarctic Drifter Experiment:…27 October, 2011 by Ailsa Stroud, Liz Thomas, Louise Sime, Robert Mulvaney
Recent developments in ice melter systems and continuous flow analysis (CFA) techniques now allow higher-resolution ice core analysis. Here, we present a new method to aid interpretation of high-resolution ice…22 October, 2011 by Robert Mulvaney
The accumulation, isotopic and chemical signals of an ice core from James Ross Island, Antarctica, are investigated for the interval from 1967 to 2008. Over this interval, comparison with station,…Read more on Environmental signals in a highly resolved ice core from James Ross Island, Antarctica
21 October, 2011 by Ed King
The Antarctic Ice Sheet loses mass to the surrounding ocean mainly by drainage through a network of ice streams: fast-flowing glaciers bounded on either side by ice flowing one or…Read more on Ice stream or not? Radio-echo sounding of Carlson Inlet, West Antarctica
16 October, 2011
All-sky CCD observations of mesospheric gravity waves have been made from Halley Station Antarctica (75.5°S, 26.7°W) as part of a collaborative research program between British Antarctic Survey, U.K. and Utah…Read more on The evolution of a breaking mesospheric bore wave packet
16 October, 2011 by Alexandra Weiss, John King, Thomas Lachlan-Cope
We study the effective aerodynamic roughness length z0_eff and scalar roughness length for temperature zT_eff over different compact sea ice types in the Antarctic Weddell Sea by aircraft measurements during…Read more on On the effective aerodynamic and scalar roughness length of Weddell Sea ice
1 October, 2011 by Eric Wolff, Robert Mulvaney
Valuable information about the environment and climate of the past is preserved in ice cores which are drilled through ice sheets in polar and alpine regions. A pivotal part of…Read more on Bayesian Glaciological Modelling to quantify uncertainties in ice core chronologies
1 October, 2011 by Nigel Meredith, Richard Horne
Using the statistical CRRES measurements of the electric field intensities of lower band chorus (LBC) and upper band chorus (UBC) around L = 6 under geomagnetically moderate conditions, we evaluate…29 September, 2011 by Louise Sime
The sensitivity of interglacial Greenland temperature to orbital and CO2 forcing is investigated using the NorthGRIP ice core data and coupled ocean-atmosphere IPSL-CM4 model simulations. These simulations were conducted in…21 September, 2011 by Markus Frey
Measurements of e-folding depth, nadir reflectivity and stratigraphy of the snowpack around Concordia station (Dome C, 75.10 S, 123.31 E) were undertaken to determine wavelength dependent coefficients (350 nm to…16 September, 2011
We investigate enhancements of mesospheric nitric acid (HNO(3)) in the Northern Hemisphere polar night regions during the January 2005 and December 2006 solar proton events (SPEs). The enhancements are caused…12 September, 2011 by Robert Larter
Overall Objective: Review existing data and identify priorities for future geoscience research (terrestrial, marine and airborne) in the Amundsen Sea embayment (ASE) region required to develop a better understanding of…8 September, 2011 by Anna Jones, Eric Wolff
Measurements of a suite of individual NOy components were carried out at Halley station in coastal Antarctica as part of the CHABLIS campaign (Chemistry of the Antarctic Boundary Layer and…1 September, 2011 by Richard Horne
Electromagnetic ion cyclotron (EMIC) waves are an integral component of the Earth's dynamic space environment. In order to quantify their effect, it is necessary to know their saturation amplitude, but…Read more on Saturation characteristic of electromagnetic ion cyclotron waves
1 September, 2011
Both observations and high resolution numerical models show that the Southern Ocean circumpolar flow is concentrated in a large number (approximately 8 to 12) of narrow filamentary jets. It is…Read more on Low frequency variability of Southern Ocean jets
27 August, 2011 by Hua Lu, Mark Clilverd
The relationship between the geomagnetic aa index and the winter North Atlantic Oscillation (NAO) has previously been found to be nonstationary, being weakly negative during the early 20th century and…23 August, 2011 by Neil Brough
The Greenland Summit Halogen-HO(x) (GSHOX) Campaign was performed in spring 2007 and summer 2008 to investigate the impact of halogens on HO(x) (= OH+HO(2)) cycling above the Greenland Ice Sheet.…15 August, 2011
The stability of the Earth's major ice sheets is a critical uncertainty in predictions of future climate and sea level change. One method of investigating the behaviour of the Greenland…Read more on Sensitivity of Pliocene ice sheets to orbital forcing
2 August, 2011 by Michael Meredith
Results from the development and analysis of a novel temperature dataset for the high latitude North-West Atlantic are presented. The new 1 degrees gridded dataset ("ATLAS") has been produced from…1 August, 2011 by Richard Horne
Plasmaspheric hiss (PH) is a band-limited, incoherent whistler mode emission found predominantly in the plasmasphere or high-density plasma regions in the near-Earth space environment. Since its discovery in the late…Read more on Modeling the evolution of chorus waves into plasmaspheric hiss
1 August, 2011 by Paul Holland
The flow of dense polar shelf waters down continental slopes is a critical component of the global ocean circulation. Recent observations suggest that such plumes can be heavily impacted by…1 August, 2011 by Richard Horne
Radiation belt dynamics have been modeled by the modified Fokker-Planck diffusion equation with sources from the low-energy plasma sheet population and losses to the atmosphere and magnetopause. We perform a…1 August, 2011 by Michael Meredith, Zhaomin Wang
The Coupled Model Intercomparison Project phase 3 (Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report) models show a consistent intensification and poleward shift of the westerly winds over the…27 July, 2011 by Steve Colwell, Tracy Moffat-Griffin
An 8 year series of 965 high-resolution radiosonde soundings over Rothera (67 degrees S, 68 degrees W) on the Antarctic Peninsula are used to study gravity wave characteristics in the…18 July, 2011 by Hugh Corr, Richard Hindmarsh, Richard Hindmarsh
The boundary of grounded ice and the location of ice transitioning to a freely floating state are mapped at 15-m resolution around the entire continent of Antarctica. These data products…18 July, 2011 by Andy Smith
We present results from new geophysical data allowing modelling of the water flow within Subglacial Lake Ellsworth (SLE), West Antarctica. Our simulations indicate that this lake has a novel temperature…16 July, 2011 by Hua Lu, Ingrid Cnossen
We analyzed observational geopotential height data to provide some new insights on the 11 year solar cycle signal in the Northern Hemisphere early winter and its modulation by the quasi-biennial…11 July, 2011 by Chester Sands, David Herbert, David Barnes, Huw Griffiths, Martin Collins, Oliver Hogg, Peter Fretwell
The multilateral failure to apply the Convention on Biological Diversity (CBD) by the target year 2010 was headline news as are the accelerating climatic changes which dictate its urgency. Some…30 June, 2011 by Richard Hindmarsh, Richard Hindmarsh
Ice domes are either axisymmetric, high points along ridges, or ridge triple junctions. We model time-dependent isothermal flow near triple junctions, solving the full set of mechanical equations with a…Read more on Flow at ice-divide triple junctions: 1. Three-dimensional full-Stokes modeling
30 June, 2011 by Ed King, Hugh Corr, Richard Hindmarsh, Robert Mulvaney, Richard Hindmarsh
Ground-based surveys of ice-divide triple junctions in two Antarctic ice rises, the Fletcher Promontory and Berkner Island, have been carried out using low-frequency ice-penetrating radars. These surveys have focused on…27 June, 2011 by Eric Wolff, Howard Roscoe
In the laboratory, we have investigated the growth and composition of frost flowers. Their ionic composition has shown little difference from those of field measurements. Young frost flowers grown on…1 June, 2011 by Hilmar Gudmundsson, Keith Nicholls
Ocean tides under the large Weddell Sea ice shelves are among the least well observed on Earth. Here we present new, spatially extensive observations of the vertical tidal motion of…1 June, 2011 by Richard Hindmarsh, Richard Hindmarsh
In East Antarctica surface mass balance data can only be obtained from the sparsely distributed ice cores when considering time periods greater than a few decades. Observations of internal layers…1 June, 2011 by Nigel Meredith
We perform a comprehensive analysis of resonant scattering of diffuse auroral electrons by oblique nightside chorus emissions present along a field line with an equatorial crossing of 6 R(E) at…1 June, 2011 by Claus-Dieter Hillenbrand
We present results of detailed paleomagnetic investigations on deep-sea cores from sediment drifts located along the Pacific continental margin of the Antarctic Peninsula. High-resolution magnetic measurements on u channel samples…25 May, 2011 by Adrian Jenkins, David Vaughan, Hugh Corr, Hamish Pritchard, Paul Holland, Robert Arthern
The air content of glacial firn determines the effect and attribution of observed changes in ice surface elevation, but is currently measurable only using labor-intensive ground-based techniques. Here a novel…23 May, 2011 by Povl Abrahamsen
This cruise report describes the combined JR252 and JR254C cruise on RRS James Clark Ross, departing Port Stanley on March 19th and arriving in Punta Arenas on April 6th. JR252…Read more on Cruise Report RRS James Clark Ross JR252 & JR254C, 19 March – 6 April 2011
12 May, 2011 by Mark Clilverd
The atmospheric chemistry general circulation model ECHAM5/MESSy is used to simulate polar surface air temperature effects of geomagnetic activity variations. A transient model simulation was performed for the years 1960-2004…1 May, 2011
Sea ice friction models are necessary to predict the nature of interactions between sea ice floes. These interactions are of interest on a range of scales, for example, to predict…1 May, 2011 by Mai Mai Lam, Nigel Meredith, Richard Horne
Electron precipitation from the Earth's inner magnetosphere transmits solar variability to the Earth's upper atmosphere and may affect surface level climate. Here we conduct a superposed epoch analysis of energetic…Read more on Energetic electron precipitation during high-speed solar wind stream driven storms
16 April, 2011 by Mark Clilverd
Utilizing observations from the Medium Energy Proton and Electron Detector (MEPED) on board the Polar Orbiting Environmental Satellite (POES) and the Microwave Limb Sounder (MLS) on board the Aura satellite,…1 April, 2011 by Anna Jones, David Maxfield, Eric Wolff, Howard Roscoe, Markus Frey, Michael Rose, Neil Brough
A suite of 10 autonomous ozone monitoring units, each powered using renewable energy, was developed and built to study surface ozone in Antarctica during the International Polar Year (2007-2009). The…1 April, 2011 by Nigel Meredith, Richard Horne
Using statistical wave power spectral profiles obtained from CRRES and the latitudinal distributions of wave propagation modeled by the HOTRAY code, a quantitative analysis has been performed on the scattering…1 April, 2011 by Nigel Meredith, Richard Horne
Using the statistical wave power spectral profiles obtained from CRRES wave data within the 0000–0600 MLT sector under different levels of geomagnetic activity and a modeled latitudinal variation of wave…1 April, 2011 by Nigel Meredith, Richard Horne
The temporal evolution of the phase space density of plasma sheet electrons (100 eV-30 keV) injected into the nightside at L = 6 during moderate geomagnetic activity is investigated using…27 March, 2011 by Hua Lu
In this study, statistical evidence of a possible modulation of the equatorial stratospheric quasi-biennial oscillation (QBO) by the solar wind dynamic pressure is provided. When solar wind dynamic pressure is…27 March, 2011
This paper describes the use of EOS Microwave Limb Sounder (MLS) data to observe the field of traveling planetary waves with quasi 16 day periods. This study utilizes MLS v2.2…Read more on Properties of the quasi 16 day wave derived from EOS MLS observations
18 March, 2011 by Richard Horne
Energetic proton (1–45 keV) distributions measured by the magnetospheric plasma analyzer detector on Los Alamos National Laboratory geosynchronous orbiting satellites are analyzed to study the characteristics of proton ring development…16 March, 2011 by Anna Jones, Eric Wolff
The concentration of atmospheric methane increased from around 360 ppbv at the last glacial maximum (∼20 ka before present) to about 700 ppbv in the pre-industrial era (∼200 years before…1 March, 2011
The international carbon cycle research community is currently coordinating the largest, most comprehensive assessment it has ever undertaken: the Regional Carbon Cycle Assessment and Processes (RECCAP; http://www.globalcarbonproject.org/reccap). The objective is…Read more on An international effort to quantify regional carbon fluxes
1 March, 2011 by Mark Clilverd
The accepted mechanism for whistler generation implicitly assumes that the causative lightning stroke occurs within reasonable proximity to the conjugate foot point of the guiding magnetic field line and that…Read more on Source region for whistlers detected at Rothera, Antarctica
1 March, 2011 by Mark Clilverd
Observed phases and amplitudes of VLF radio signals propagating on a short (∼360 km) path are used to find improved parameters for the lowest edge of the (D region of…28 January, 2011
On 16–17 July 2007 during an observational campaign at Comandante Ferraz Antarctic Station (62 degrees S, 58 degrees W), a mesospheric wall was observed with an airglow all-sky imager. The…Read more on Case study of a mesospheric wall event over Ferraz station, Antarctica (62° S)
27 January, 2011 by Gareth Chisham, Mervyn Freeman
We report a superposed epoch analysis of the hemispheric open magnetic flux, maximum nightside auroral intensity, geomagnetic activity, and solar wind and interplanetary magnetic field conditions around the time of…27 January, 2011 by Hua Lu, Ingrid Cnossen
We use a troposphere-stratosphere model of intermediate complexity to study the atmospheric response to an idealized solar forcing in the subtropical upper stratosphere during Northern Hemisphere (NH) early winter. We…Read more on Solar signal propagation: The role of gravity waves and stratospheric sudden warmings
1 January, 2011 by Vsevolod Afanasyev
Each autumn billions of songbirds migrate between the temperate zone and tropics, but little is known about how events on the breeding grounds affect migration to the tropics. Here, we…1 January, 2011 by Katrin Linse
Three hundred and fifty specimens of the endemic Southern Ocean octopus genus Pareledone, were sequenced for the barcoding gene COI. Geographic coverage comprised the South Shetland Islands, the Ross Sea,…1 January, 2011 by Claire Allen
Sea-ice growth and decay in Antarctica is one of the biggest seasonal changes on Earth, expanding ice cover from 4 106 km2 to a maximum of 19 106 km2 during…1 January, 2011 by Claire Allen
We have developed cleaning methods for extracting diatomopal from bulk marine sediment samples, for measurement of both zinc (Zn) abundance and isotope composition. This cleaning technique was then applied to…1 January, 2011 by Mark Belchier
Patagonian toothfish (Dissostichus eleginoides) or ‘Chilean sea bass’ support a valuable and controversial fishery, yet their life history is not well understood and longevity estimates range from ~20 to >50…1 January, 2011
A global chemistry-climate model is used to assess the impact on atmospheric composition of the regeneration and recycling of HOx in the photo-oxidation of isoprene. The impact is explored subject…1 January, 2011 by Kevin Hughes
Antarctica is the most isolated continent on Earth, but it has not escaped the negative impacts of human activity. The unique marine ecosystems of Antarctica and their endemic faunas are…Read more on Anthropogenic impacts on marine ecosystems in Antarctica
1 January, 2011 by Eric Wolff
We constructed an 800,000-year synthetic record of Greenland climate variability based on the thermal bipolar seesaw model. Our Greenland analog reproduces much of the variability seen in the Greenland ice…1 January, 2011 by Andrew Clarke, David Barnes
Antarctica is a continent of extremes: on average it is the highest, windiest, coldest and driest land mass on Earth. It also has the largest ice-mass, with less than 1%…1 January, 2011 by David Barnes, Terri Souster, Terri Souster
The West Antarctic Peninsula (WAP) is a hotspot of recent rapid regional warming and ice loss1. The WAP sea surface freezes each winter to form a ‘fast-ice’ skin that can…Read more on Reduced survival of Antarctic benthos linked to climate-induced iceberg scouring
1 January, 2011 by Povl Abrahamsen
Extremely low summer sea-ice coverage in the Arctic Ocean in 2007 allowed extensive sampling and a wide quasi-synoptic hydrographic and δ18O dataset could be collected in the Eurasian Basin and…Read more on Origin of freshwater and polynya water in the Arctic Ocean halocline in summer 2007
1 January, 2011 by Fausto Ferraccioli, Hugh Corr, Tom Jordan
An International Polar Year aerogeophysical investigation of the high interior of East Antarctica reveals widespread freeze-on that drives substantial mass redistribution at the bottom of the ice sheet. Although the…1 January, 2011 by Dominic Hodgson, Joanne Johnson
Glacial geological evidence of rapid ice stream retreat is important for the potential insight it can bring to understanding of contemporary rapid ice sheet change. Here, we report new chronological…Read more on Rapid deglaciation of Marguerite Bay, western Antarctic Peninsula in the Early Holocene
1 January, 2011 by David Vaughan
Observations from satellite and airborne platforms are combined with model calculations to infer the nature and efficiency of basal melting of the Pine Island Glacier ice shelf, West Antarctica, by…Read more on Variability of basal melt beneath the Pine Island Glacier ice shelf, West Antarctica
1 January, 2011 by Richard Phillips
Relationships between events in one period of the annual cycle and behaviour in subsequent seasons are key determinants of individual life histories and population dynamics. However, studying such associations is…1 January, 2011 by Peter Convey
Passive chambers are used to examine the impacts of summer warming in Antarctica but, so far, impacts occurring outside the growing season, or related to extreme temperatures, have not been…1 January, 2011 by Thomas Bracegirdle
The semi-annual oscillation (SAO) in sea-level pressure at high southern latitudes is the consequence of a twice-yearly contraction (and strengthening) and expansion (and weakening) of the storm track between 50…1 January, 2011 by Katrin Linse
The benthic fauna was investigated during the expedition ANT-XXIV/2 (2007/08) in relation to oceanographic features, biogeochemical properties and sediment characteristics, as well as the benthic, pelagic and air-breathing fauna. The…Read more on Maud Rise – a snapshot through the water column
1 January, 2011 by Lloyd Peck, Melody Clark
Echinoderms and in particular brittle stars display a remarkable ability to regenerate lost or damaged tissues. They offer an excellent model in which to study regeneration displaying extensive regenerative ability…1 January, 2011 by Vsevolod Afanasyev
The population decline of the Lesser Kestrel Falco naumanni has been the subject of studies across its Western Palaearctic breeding range, but little is known about its use of pre-migratory…1 January, 2011 by Richard Phillips
Although seabirds that are trans-equatorial migrants show apparently broad overlap among populations in the non-breeding season, such large-scale pattern may conceal subtle but nevertheless key differences in migratory behaviour. These…1 January, 2011 by Jaume Forcada
Black-browed albatrosses Thalassarche melanophris are currently classified as globally endangered. The most important populations of this species are believed to be declining due to, amongst other factors, unsustainable levels of…1 January, 2011 by Richard Phillips
It has long been known that birds change their behaviour, reproductive performance and survival as they mature, including in the first few years after recruitment into the breeding population. However,…1 January, 2011 by Lloyd Peck, Michael Thorne, Melody Clark
Background: The Antarctic krill Euphausia superba is a keystone species in the Antarctic food chain. Not only is it a significant grazer of phytoplankton, but it is also a major…Read more on Antarctic krill 454 pyrosequencing reveals chaperone and stress transcriptome
1 January, 2011 by David Pearce
One of the most remarkable discoveries resulting from the robotic and remote sensing exploration of space is the inferred presence of bodies of liquid water under ice deposits on other…Read more on Subglacial environments and the search for life beyond the Earth
1 January, 2011
The Twentieth Century Reanalysis (20CR) project is an international effort to produce a comprehensive global atmospheric circulation dataset spanning the twentieth century, assimilating only surface pressure reports and using observed…1 January, 2011 by Peter Convey
Recent analyses of Antarctic terrestrial biodiversity data, in combination with molecular biological studies, have created a new paradigm that long-term persistence and regional isolation are general features of most of…Read more on Antarctic terrestrial biodiversity in a changing world
1 January, 2011 by Peter Convey, Stephen Roberts
The ecosystems of the western Antarctic Peninsula, experiencing amongst the most rapid trends of regional climate warming worldwide, are important “early warning” indicators for responses expected in more complex systems…Read more on Global southern limit of flowering plants and moss peat accumulation
1 January, 2011 by Mark Belchier, Peter Convey
The human-assisted establishment of two non-native predatory carabid beetles (Merizodus soledadinus (Guerin-M,n,ville), Trechisibus antarcticus (Dejean)) on the sub-Antarctic island of South Georgia occurred 30-50 years ago, but the distribution of…Read more on Recent range expansions in non-native predatory beetles on sub-Antarctic South Georgia
1 January, 2011 by Kevin Hughes, Peter Convey
The Antarctic continent is frequently cited as the last pristine continent on Earth. However, this view is misleading for several reasons. First, there has been a rapid increase in visitors…Read more on Non-indigenous microorganisms in the Antarctic: assessing the risks
1 January, 2011 by Jonathan Watkins
Antarctic krill are important in the South Georgia (548S 358W) marine ecosystem. They form aggregations that vary widely in packing density (,1 to 1000 s of individuals m23), length (tens…1 January, 2011 by Pierre Dutrieux
The Solomon Sea, in the western tropical Pacific, is part of a major oceanic pathway for waters connecting the tropics to the equator via low latitude western boundary currents. Shipboard…Read more on Observed circulation in the Solomon Sea from SADCP data
1 January, 2011
Diatom cells have distinctive optical characteristics, originating from their relatively large cell size, fucoxanthin content and silica cell wall. It has been proposed that diatom-dominated phytoplankton blooms can be identified…1 January, 2011 by Eugene Murphy
Determining the form of key predator-prey relationships is critical for understanding marine ecosystem dynamics. Using a comprehensive global database, we quantified the effect of fluctuations in food abundance on seabird…Read more on Global seabird response to forage fish depletion – one-third for the birds
1 January, 2011
The Citarum river basin of western Java, Indonesia, which supplies water to 10 million residents in Jakarta, has become increasingly vulnerable to anthropogenic change. Citarum's streamflow record, only similar to…