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1

Water treatment design for site remediation at Casey Station, Antarctica: site characterisation and particle separation  

Microsoft Academic Search

Antarctica is commonly regarded as a pristine environment, but more than a century of human activity has left an extensive legacy of abandoned waste. The Australian Antarctic Division (AAD) has identified the Thala Valley Tip near Casey Station as a high priority site for remediation. However, there are difficulties with regards to contaminant dispersal by melt-water during extraction of wastes

Kathy A. Northcott; Ian Snape; Michael A. Connor; Geoffrey W. Stevens

2003-01-01

2

Cost-efficient methods for marine pollution monitoring at Casey Station, East Antarctica: the choice of sieve mesh-size and taxonomic resolution  

Microsoft Academic Search

Contaminants from sewage discharge and abandoned waste tips enter the marine environment adjacent to Australia’s Casey Station, East Antarctica. To establish cost-efficient methods for benthic pollution monitoring the effects of sieve mesh-size (0.5 and 1.0 mm) and taxonomic aggregation (family, order and class) on the description of infaunal assemblages were determined. The abundance and taxonomy of fauna retained on a

Belinda W Thompson; Martin J Riddle; Jonathan S Stark

2003-01-01

3

Multiple Pb sources in marine sediments near the Australian Antarctic Station, Casey.  

PubMed

An extensive Pb isotope ratio survey of approximately 100 marine sediment samples from near Casey Station, East Antarctica has been undertaken. Sediment surface grabs and cores were collected over nine years between 1997-2006 and, following HF total digestion, were analysed by magnetic sector ICP-MS. Fifty-two reference samples ([Pb] range 5-26 mg kg(-1)) from 6 non-impacted locations displayed a broad range of Pb isotope ratios representative of the natural background geology of the region ((208)Pb/(204)Pb ratios of 37.5-40; (206)Pb/(204)Pb ratios of 17-19). Potentially impacted sediments from Brown Bay (n=27, [Pb] range 18-215 mg kg(-1)), adjacent to the current and former Australian Stations at Casey (and the associated Thala Valley tip site) showed contamination by Pb characteristic of Broken Hill and Mt Isa Australian deposits ((208)Pb/(204)Pb and (206)Pb/(204)Pb values of 35.5-36 and 16.0-16.1, respectively). The nearby abandoned Wilkes Station was previously manned by both US (1957-59) and Australian (1959-69) expeditioners. Adjacent marine sediment samples (n=24, [Pb] range 13-40 mg kg(-1)) displayed Pb isotopic signatures suggesting anthropogenic input from multiple sources. On a three-isotope diagram Wilkes sediments were found to display Pb ratios lying intermediate between Missouri (US), Broken Hill/Mt Isa (Australia)/Idaho (US), and natural geogenic Pb end members. Discarded Pb batteries, paint samples and fuel spills were all considered in this work as possible point sources of Pb contamination to the local environment. Batteries are thought to be the dominant source. PMID:17961635

Townsend, A T; Snape, I

2007-10-24

4

Antarctica: A Southern Hemisphere Windpower Station?  

Microsoft Academic Search

The International Polar Year commences in 2007. We offer a macroproject plan to generate a large amount of electricity on the continent of Antarctica by using sail-like wind dams incorporating air turbines. Electricity can be used to make exploration and exploitation efforts on Antarctica easier. We offer the technical specifications for the Fabric Aerial Dam and indicate some of the

Alexander A. Bolonkin; Richard B. Cathcart

2007-01-01

5

Station Climatic Summaries: Antarctica, Australia and Oceania.  

National Technical Information Service (NTIS)

This report contains summarized monthly and annual climatic data for specific locations in Antarctica, Australia, and Oceania. Summarized climatology elements are: percent frequency of occurrence of ceiling and visibility; means, extremes and number of da...

1990-01-01

6

PM(10) source apportionment at McMurdo Station, Antarctica  

Microsoft Academic Search

This source apportionment of PM10 (particulate matter with an aerodynamic diameter of 10 microns or less) resulted from a two year field study performed during the 1995-1996 and 1996-1997 austral summers at McMurdo Station, Antarctica. Source and ambient samples were collected and analyzed for PM10 mass, anions (chloride, fluoride, nitrate, sulfate, and methanesulfonate), cations (sodium, potassium, and ammonium), elemental and

David Mark Mazzera

1999-01-01

7

Surface Flux Measurements at King Sejong Station in West Antarctica  

NASA Astrophysics Data System (ADS)

The Antarctic Peninsula is important in terms of global warming research due to pronounced increase of air temperature over the last century. The first eddy covariance system was established and turbulent fluxes of heat, water vapor, CO2 and momentum have been measured at King Sejong Station (62 \\deg 13øØS, 58 \\deg 47øØW) located in the northern edge of the Antarctic Peninsula since December in 2002. Our objectives are to better understand the interactions between the Antarctic land surface and the atmosphere and to test the feasibility of the long-term operation of eddy covariance system under extreme weather conditions. Various lichens cover the study area and the dominant species is Usnea fasciata-Himantormia. Based on the analyses on turbulent statistics such as integral turbulence characteristics of vertical velocity (w) and heat (T), stationarity test and investigation of correlation coefficient, they follow the Monin-Obukhov similarity and eddy covariance flux data were reliable. About 50 % of total retrieved sensible heat flux data could be used for further analysis. We will report on seasonal variations of energy and mass fluxes and environmental variables. In addition, factors controlling these fluxes will be presented. Acknowledgement: This study was supported by ¡rEnvironmental Monitoring on Human Impacts at the King Sejong Station, Antarctica¡_ (Project PP04102 of Korea Polar Research Institute) and ¡rEco-technopia 21 project¡_ (Ministry of Environment of Korea).

Choi, T.; Lee, B.; Lee, H.; Shim, J.

2004-12-01

8

Production of antibiotics and enzymes by soil microorganisms from the windmill islands region, Wilkes Land, East Antarctica  

Microsoft Academic Search

The distribution of microorganisms in four soil samples taken near Casey Station, Wilkes Land, and on Dewart Island, Frazier\\u000a Islands (East Antarctica), was studied using isolation cultures at different temperatures. The fungal assemblages comprised Penicillium, Alternaria, Cladosporium, Phoma, Verticillium, Phialophora, Candida and Rhodotorula. Microalgal Chlorophyta were also common. Among the bacteria representatives of cyanobacteria, Staphylococcus, Bacillus, Pantoea, Streptomyces, Micromonospora, and

Victoria Gesheva

2010-01-01

9

Baseline metal concentrations in Paramoera walkeri from East Antarctica  

Microsoft Academic Search

Remediation of the Thala Valley waste disposal site near Casey Station, East Antarctica was conducted in the austral summer of 2003\\/2004. Biomonitoring of the adjacent marine environment was undertaken using the gammaridean amphipod Paramoera walkeri as a sentinel species [Stark, J.S., Johnstone, G.J., Palmer, A.S., Snape, I., Larner, B.L., Riddle, M.J., in press, doi:10.1016\\/j.marpolbul.2006.05.020. Monitoring the remediation of a near

Anne S. Palmer; Ian Snape; Jonathan S. Stark; Glenn J. Johnstone; Ashley T. Townsend

2006-01-01

10

Outdoor Education, Camp Casey.  

ERIC Educational Resources Information Center

|A curriculum guide for the Camp Casey Outdoor Education program is contained in this document. Designed for fifth grade students and teachers in Northshore School District, Bothell, Washington, it emphasizes learning activities for use in the outdoors. General understandings relevant to the objectives of the program form the frame into which the…

Stansberry, Steve; And Others

11

Outdoor Education, Camp Casey.  

ERIC Educational Resources Information Center

A curriculum guide for the Camp Casey Outdoor Education program is contained in this document. Designed for fifth grade students and teachers in Northshore School District, Bothell, Washington, it emphasizes learning activities for use in the outdoors. General understandings relevant to the objectives of the program form the frame into which the…

Stansberry, Steve; And Others

12

Measurement of black carbon at Syowa station, Antarctica: seasonal variation, transport processes and pathways  

Microsoft Academic Search

Measurement of black carbon (BC) was carried out at Syowa station Antarctica (69° S, 39° E) from February 2004 until January 2007. The BC concentration at Syowa ranged from below detection to 176 ng m-3 during the measurements. Higher BC concentrations were observed mostly under strong wind (blizzard) conditions due to the approach of a cyclone and blocking event. The

K. Hara; K. Osada; M. Yabuki; M. Hayashi; T. Yamanouchi; M. Shiobara; M. Wada

2008-01-01

13

Monthly scale surface ozone depletion during polar sunrise in 2006 observed at Syowa Station, Antarctica  

Microsoft Academic Search

Surface ozone concentration is monitored at Syowa Station, Antarctica since 1988. The ozone concentration shows clear seasonal cycle with the maximum value in June - July and the minimum value in January reflecting both the seasonal varied intrusion of stratospheric air and the transport of air from sub-polar or middle latitude through lower troposphere in addition to the photochemical destruction.

T. Watai; G. Hashida; T. Yamanouchi

2008-01-01

14

Surface radiation balance in Antarctica as measured with automatic weather stations  

Microsoft Academic Search

We present 4 years of near-surface radiation balance observations of four Antarctic automatic weather stations (AWS). The AWS are situated along a traverse line in Dronning Maud Land, connecting the coastal ice shelf and the inland plateau via the katabatic wind zone, covering the three major climate regimes of East Antarctica. Important differences in the radiation balance of the three

Michiel van den Broeke; Carleen Reijmer; Roderik van de Wal

2004-01-01

15

Burying An Imaging Riometer At Halley Station, Antarctica: A Lesson For Other Riomter Users  

Microsoft Academic Search

This poster describes the unique approach used to deploy an Imaging Riometer system at Halley Station (75S 26W), Antarctica. For practical reasons the antenna array is permanently buried under ice, and we describe how the antenna design was modified to facilitate this. The effect of snow accumulation on the array performance during the burial process is examined, and its importance

M. C. Rose; M. J. Jarvis

2002-01-01

16

Installation of very broadband seismic stations to monitor cryospheric environment, Antarctica  

NASA Astrophysics Data System (ADS)

Korea Polar Research Institute (KOPRI) has successfully installed two autonomous very broadband seismic stations in the King George Island (KGI), Antarctica, during the 24th KOPRI Antarctic Summer Expedition. The seismic observation system is originally designed by the Incorporated Research Institutions for Seismology (IRIS) Program for Array Seismic Studies of the Continental Lithosphere (PASSCAL) Instrument Center, which are compatible with the Polar Earth Observing Network (POLENET) seismic system. The installation is aiming at the following major subjects: 1. Monitoring local earthquakes and icequakes in and around the KGI, 2. Validating the robustness of seismic system operation under harsh environment. Once we achieve the goals, we plan to move and install them adding a couple more stations at ice shelf systems, e.g., Larsen Ice Shelf System, Antarctica (LARISSA), to figure out physical interaction between the Solid-Earth and ice shelf system in near future.

Lee, W.; Seo, K.; Yun, S.; Lee, T.; Choe, H.; Yoon, H.; Chae, N.

2011-12-01

17

Seasonal variation of seismic ambient noise level at King Sejong Station, Antarctica  

NASA Astrophysics Data System (ADS)

The generation of the secondary- or double-frequency (DF) microseisms with dominant frequencies between 0.1 and 0.5 Hz has been explained by nonlinear second-order pressure perturbations on the ocean bottom due to the interference of two ocean waves of equal wavelengths traveling in opposite directions. Korea Polar Research Institute (KOPRI) has been operating a broadband seismic station (KSJ1) at King George Island (KGI), Antarctica, since 2001. Examining the ambient seismic noise level for the period from 2006 to 2008 at KSJ1, we found a significant seasonal variation in the frequency range 0.1-0.5 Hz. Correlation of the DF peaks with significant ocean wave height and peak wave period models indicates that the oceanic infragravity waves in the Drake Passage is a possible source to excite the DF microseisms at KGI. Location of King Sejong Station, Antarctica Seasonal variations of DF peak, significant wave height, and peak wave period

Lee, W.; Sheen, D.; Seo, K.; Yun, S.

2009-12-01

18

Bursts of cloud condensation nuclei (CCN) by dissipating clouds at Palmer Station, Antarctica  

Microsoft Academic Search

The authors present here a case study of cloud-mediated production of cloud condensation nuclei (CCN) recorded at Palmer Station (64°46`S, 64°05`W), Antarctica on 20 Jan 1994. Four instances of CCN bursts occured on January 17, 19, 20 and February 7, 1994 when cloud base descended to the surface and dissipated under prevailing meteorlogical conditions. The most spectacular event ocurred on

V. K. Saxena

1996-01-01

19

Alien lichens unintentionally transported to the “Arctowski” station (South Shetlands, Antarctica)  

Microsoft Academic Search

The recent climate changes combined with intensified human activity in Antarctica are promoting the synanthropization process\\u000a and increasing the likelihood of alien species establishing in the native communities. Cargo items, expedition members’ equipment\\u000a and food destined for the 32nd Polish Antarctic Expedition to the “Arctowski” station in the 2007\\/2008 season were inspected\\u000a to determine their potential as vectors for alien

Piotr Osyczka

2010-01-01

20

Absolute-gravity stations in Western Dronning Maud Land, Antarctica  

NASA Astrophysics Data System (ADS)

Absolute-gravity stations are an important part of the geodetic infrastructure of the Antarctic. They provide accurate starting values for gravity surveys performed e.g. for the determination of the geoid, for geological studies and for geophysical investigations. The time variation in gravity determined from repeated absolute-gravity measurements provides insights into the Glacial Isostatic Adjustment (GIA) and into solid Earth deformation due to variation in contemporary ice load. Given sufficient joint coverage with International Terrestrial Reference Frame (ITRF) sites, gravity rates in high latitudes could in principle provide an independent check of the geocentricity of the z-dot (velocities in the direction of the rotation axis of the Earth) of the ITRF. We review the absolute gravity stations in Western and Central Dronning Maud Land. The oldest station is at the Finnish base Aboa, with 5 measurements by the Finnish Geodetic Institute (FGI) starting with the FINNARP 1993 expedition. Measurements at Maitri (India) and Novolazarevskaya (Russia) were first performed in 2004 by the National Geophysical Research Institute (NGRI) of India, and by the FGI, respectively. In the season 2010/11 a new station was constructed at Troll (Norway). In the season 2011/12 the aforementioned four sites were occupied by the FG5-221 absolute gravimeter of the FGI. At Sanae IV (South Africa) there are previous occupations by the FG5-221, in 2003/4 and 2005/6. All these bases have continuous GNSS stations. Numerous supporting measurements have been made at the sites: microgravity networks, levelling and GNSS ties to excentres etc., for controlling the stability of the stations. At some sites, nearby glacier elevations were surveyed to monitor the attraction of the variable close-field snow and ice masses. We give a description of the sites and the measurements performed at them. The work has benefited from the co-operation in the COST Action ES0701 "Improved Constraints on Models of GIA".

Mäkinen, Jaakko; Rasindra, Ravik; Chand, Uttam; Tiwari, Virendra; Lukin, Valery; Anisimov, Michail; Melvaer, Yngve; Melland, Gudmund; Koivula, Hannu; Näränen, Jyri; Poutanen, Markku

2013-04-01

21

Dome Fuji Station in East Antarctica and the Japanese Antarctic Research Expedition  

NASA Astrophysics Data System (ADS)

Japanese Antarctic Research Expedition (JARE) commenced on the occasion of International Geophysical Year in 1957-1958. Syowa Station, the primary station for JARE operations, is located along the northeastern coastal region of Lützow-Holm Bay, East Antarctica (69° 00'S, 39° 35'E), and was opened on 29 January 1957. Since then, JARE have been carrying out research in various fields of earth and planetary sciences and life science. Astronomical science, however, has not been popular in Antarctica. In 1995, JARE established a new inland station, Dome Fuji Station (77° 19'S, 39° 42'E), which, at 3,810 m a.s.l., is located on one of major domes of the Antarctic ice sheet, some 1,000 km south of Syowa. The climatic conditions at Dome Fuji are harsh, with an annual average air temperature of -54°C, and a recorded minimum of -79°C. In 2007, JARE completed scientific drilling to obtain ice core samples of the Antarctic ice sheet reaching 3,050 m in depth. These ice cores record environmental conditions of the earth extending back some 720,000 B.P. In recent years, it is widely known that the high-altitude environment of inland Antarctica is suitable for astronomical observations and the Japanese astronomy community identified Dome Fuji Station as a potential candidate for a future astronomical observatory. In this article, the history of Japanese Antarctic activities are described in terms of access to the inland plateau of the Antarctic continent. The general scheme and future plans of science objectives and logistics of JARE will also be introduced.

Shiraishi, Kazuyuki

2013-01-01

22

VLF wave stimulation experiments in the magnetosphere from Siple Station, Antarctica  

SciTech Connect

The experimental methods used in the VLF stimulation experiments at the Siple Station, Antarctica, are described together with the results of observations and their interpretations. Consideration is given to the equipment employed in the experiments, with special attention to the Jupiter VLF transmitter, and to the methodology used to stimulate VLF signals. Data are presented on the following types of experiments: (1) single-frequency growth and triggering, (2) frequency ramp, (3) multifrequency, and (3) noise simulation. The possibilities for new controlled VLF wave injection experiments in the earth's magnetospheric plasma are discussed. 44 references.

Helliwell, R.A.

1988-08-01

23

Meso-scale auroral dynamics at magnetically conjugate points at Syowa Station, Antarctica and Iceland  

NASA Astrophysics Data System (ADS)

Simultaneous observations of interhemispheric conjugate auroras provide a unique opportunity to examine how and where the invisible geomagnetic field lines connect the two hemispheres. Conjugate aurora should help us to infer the physical nature of auroral phenomena which occur between the magnetosphere and the ionosphere. Syowa Station in Antarctica and stations in Iceland form an ideal set of observatories to study geomagnetically conjugate optical auroras in the auroral zone. Conjugate auroral observations using all-sky TV cameras has been carried out since 1984 during the equinox periods. Using selected events, the dynamics of conjugate auroral features and the dynamic tracing of footprint of real geomagnetic conjugate point of Syowa, with temporal and spatial resolution of ~10 minute and ~10 km, was possible. Dynamic longitudinal displacement of conjugate point was strongly affected by the orientation of interplanetary magnetic field (IMF).

Sato, N.; Kadokura, A.; Motoba, T.; Hosokawa, K.; Bjornsson, G.; Saemundsson, T.

2011-12-01

24

Year Round Operation of Autonomous, Low Power Geophysical Stations in Antarctica  

NASA Astrophysics Data System (ADS)

Year round operation of autonomous, low power geophysical stations in Antarctica presents both technical and logistical challenges. Prior to 2005, few if any autonomous seismic or GPS stations operated continuously throughout the austral winter. There are two basic environmental challenges in Antarctica beyond the logistical challenge: the margins with relatively mild temperatures but extreme winds and the Polar Plateau with extreme temperatures but relatively little wind. Large caches of lead-acid batteries can operate stations on the Antarctic margins where temperatures are relatively high, but are logistically expensive and will not survive the extreme temperatures of the Polar Plateau. Primary lithium thionyl chloride batteries have been proven to be successful and economical for use in the extreme plateau environment. These technical and logistical challenges were the focus of an IRIS/PASSCAL-UNAVCO collaboration to design power and communications for a < 5W system capable of continuous operation without intervention for two years. This collaboration has resulted in the successful operation of close to 100 GPS and seismic stations on several IPY projects with better than 80% data return. Our systems were designed to challenging logistical constrains for increased efficiency in polar operations. These year-round systems can now be deployed in a single twin otter flight. The IRIS/PASSCAL-UNAVCO collaboration has resulted in deployable systems backed by facilities with proven track records of longevity of technical field support. Our expertise and sustained engineering has resulted in a robust community product. We have significantly lowered the barriers of entry to scientists who desire year-round autonomous data collection in the Polar regions. A transparent development process with broad community support and input has resulted in a new generation of GPS and seismic systems fielded on several major IPY projects. The challenge now is how to keep the development and testing effort sustained to take advantage of the evolving renewable energy research.

Beaudoin, B. C.; White, S.; Bonnett, B.; Parker, T.; Johns, B.; Anderson, K. R.

2009-12-01

25

An automatic snow station experiment in Western Dronning Maud Land, Antarctica  

NASA Astrophysics Data System (ADS)

Snow and ice cover 98% of all surfaces in Antarctica and it is one of the principal components of our global climate system. Snow properties easily respond to changes in environmental conditions and therefore studying the spatio-temporal variations in the physical properties of Antarctic snow cover is crucial. We present here results from a snow station experiment recording the temperature evolution of the snow surface layer over one year in two stations. The snow stations were installed in December 2009 to measure the snow temperature at 15 different depths for one year, the deepest sensor being at 4 m at the moment of installation. The stations were recovered in January 2011 and both were still fully operational. It was the first time when this kind of experiment was successful in the western Dronning Maud Land. The stations were located 50 km (station 1) and 10 km (station 2) from the Finnish research station Aboa (73o 02.5'S, 013o24.4'W), 80 and 130 km south of the ice shelf edge. The temperature data are analyzed for the annual temperature cycle of surface layer temperature, surface heat budget, and net snow accumulation. The power spectra of temperature at the depth of 54 cm were calculated for the whole measurement interval, and separately for the polar night and polar day seasons. The daily cycle was strong during the polar day but disappeared when the polar night started. The daily cycle is also seen when looking over the whole measurement interval. Also physical characterization of the snow stratigraphy was made at the installation sites at the start and end of the recordings, including thickness, density, hardness (hand test), and grain size and shape (photographs from crystals). Also the dielectric constant was measured using the Snow Fork (designed and manufactured by Toikka Oy) to estimate the liquid water content (wetness).

Järvinen, O.; Leppäranta, M.

2012-04-01

26

Casey Doyle: Artist at Play  

ERIC Educational Resources Information Center

|The article discusses the work of Casey Doyle, and the narrative metaphors and personal explorations that inform his sculptures and how, for his undergraduate thesis, he selected a body of work whose central theme explores his identity as a gay man, informing his relationships with family, friends and society. (Contains 5 figures.)|

Sanders, James H., III; Doyle, Casey

2008-01-01

27

Quantification of polycyclic aromatic hydrocarbons in soil at McMurdo Station, Antarctica.  

PubMed

Polycyclic aromatic hydrocarbons (PAHs) are a group of compounds that have attracted much attention over the past several years. The United States Environmental Protection Agency (USEPA) has identified numerous PAHs as known or probable human carcinogens. The quantity of PAHs in the environment has dramatically increased, with the majority emitted from fossil fuel combustion sources. Surface soil samples were collected at McMurdo Station, Antarctica (77 degrees 51S, 166 degrees 41E), during peak summer activity and analyzed for PAHs. PAHS were detected at several locations, with maximum concentrations for naphthalene, acenaphthene, acenaphthylene, and fluoranthene at 27,000, 17,800, 15,700 and 13,300 mg/kg, respectively. Results suggest anthropogenic activities may be contributing to increased levels of PAHs present in McMurdo soils. PMID:10454905

Mazzera, D; Hayes, T; Lowenthal, D; Zielinska, B

1999-05-01

28

Ozone and temperature profiles over McMurdo Station Antarctica in the Spring of 1989  

SciTech Connect

Ozone and temperature were measured in 39 balloon soundings at McMurdo station Antarctica (78{degree}S) in the spring of 1989. Compared to 1986 and 1988 the stratosphere was colder and ozone depletion worse. Compared to 1987 the stratosphere warmed earlier but ozone depletion was similar, both in the magnitude and rate of depletion. Within regions of the atmosphere in 1989 ozone depletion was between 80 and 98% complete. This was again similar to 1987 and suggests that conditions observed in 1987 exceeded the minimum required for rapid and complete ozone depletion. As in previous years ozone was destroyed primarily between 12 and 20 km and there were several short periods, < 5 days, when rapid depletion was observed.

Deshler, T.; Hofmann, D.J.; Hereford, J.V.; Sutter, C.B. (Univ. of Wyoming (USA))

1990-02-01

29

Mesospheric nitric oxide (NO) enhancements above Troll Station, Antarctica during March-May 2008  

NASA Astrophysics Data System (ADS)

Nitric oxide (NO) vertical volume mixing ratio profiles, measured using a ground-based passive sub-millimetre (250 GHz) radiometer at Troll Station, Antarctica (72.0 ° S, 2.5 ° E, invariant latitude 62.5° ), are reported for a 50-day period during March-May 2008. Enhanced levels of mesospheric NO are observed in the 75 km-90 km altitude range following a series of small geomagnetic storms (peak Ap index daily mean of 36) close to the minimum of solar cycle 23. Detailed analysis of the period 26 March to 3 April (2008 days 86-94) with 3-hour temporal resolution indicates significant differences in night-time and day-time production of odd nitrogen (NOx ). The characteristics of the energetic particle flux and energy spectrum and its impact on atmospheric chemistry have been investigated using the Sodankylü Ion-Neutral Chemistry a (SIC) model.

Newnham, David; Espy, Patrick; Clilverd, Mark; Rodger, C. J.; Seppala, Annika; Maxfield, David; Hartogh, Paul

30

Column ozone measurements from Palmer Station, Antarctica: Variations during the Austral Springs of 1988 and 1989  

SciTech Connect

The National Science Foundation scanning spectroradiometer at Palmer Station, Antarctica (64{degree}-46{prime}S, 64{degree}04{prime}W), provides hourly ground-based measurements of solar ultraviolet (UV) irradiance. In addition to defining the UV radiation environment of the region, these measurements allow the derivation of the column density of atmospheric ozone above the station nearly every daylight hour. This hourly time resolution, not generally available from other methods of monitoring Antarctic ozone abundances, enables the detection of large and rapid changes in total column ozone and UV surface irradiance associated with the dynamics of the polar vortex. Column ozone abundance is derived from a ratio of measured irradiances at 300 and 313.5 nanometers (nm) by means of theoretical calculation of this ratio as a function of total ozone amount. Noontime ozone abundances over Palmer Station obtained from this method agree with those obtained by the Total Ozone Mapping Spectrometer (TOMS) instrument aboard Nimbus 7 to within about 10% throughout the austral spring of 1988. Ozone recovery at Palmer Station, associated with the breakup of the polar vortex as indicated by TOMS satellite ozone observations, occurred rapidly within a 24-hour period beginning in midafternoon on November 15. Over the Antarctic Peninsula, the 1989 ozone depletion was slightly greater than in 1988, the minimum noontime ozone abundances over Palmer Station as measured by the spectroradiometer being 194 and 166 Dobson units for October 14, 1988, and October 14, 1989, respectively. The 1989 ozone depletion however ended by November 5 over the Antarctic Peninsula, 10 days earlier than the 1988 event.

Lubin, D. (Univ. of California, San Diego, La Jolla (USA)); Frederick, J.E. (Univ. of Chicago, IL (USA))

1990-08-20

31

Monthly scale surface ozone depletion during polar sunrise in 2006 observed at Syowa Station, Antarctica  

NASA Astrophysics Data System (ADS)

Surface ozone concentration is monitored at Syowa Station, Antarctica since 1988. The ozone concentration shows clear seasonal cycle with the maximum value in June - July and the minimum value in January reflecting both the seasonal varied intrusion of stratospheric air and the transport of air from sub-polar or middle latitude through lower troposphere in addition to the photochemical destruction. Surface ozone depletion (SOD) prolonged for about a month was observed in July 2006. The SOD during polar sunrise was sometimes observed in polar region; however, its duration was almost a several days. Monthly scale SOD was rarely observed. The atmospheric temperature was considerably low in July 2006 and the monthly averaged value of -24.1°C recorded lowest value in history at Syowa Station. Inspection of potential height at 500 hPa suggests Syowa Station was situated in polar vortex that intensified in July relative to anteroposterior months. Backward trajectory shows no intrusion of lower troposphere air from sub-polar region or mid latitude. Variation of greenhouse gases observed simultaneously at Syowa Station shows no local contamination occurred. Ozone concentration is known to decrease by dry deposition and photochemical destruction with halogen species. Its reaction and also release of halogen species from sea surface is active under low temperature. Another factor leading monthly scale SOD was considered to be bromine that accumulated into snow layer. Blizzard was rarely observed in previous month (June 2006) at the station, but observed a few times in July 2006. This phenomenon implies the possibility that the bromine accumulated into snow during June was released into atmosphere in July and activated the photochemical reaction under polar sunrise. These evidence suggests that the monthly scale SOD observed at Syowa Station in July 2006 is probably caused by 1) holding of extremely low temperature around Syowa Station caused by intense and continued polar vortex, 2) formation of inversion layer over the ground surface caused by extremely low temperature, 3) increase of Br- and BrO release, which excites catalytic cycle of ozone destruction, from sea surface and its activated reaction at record low temperature, 4) diffusion of Br- particle stored in snow to lower troposphere by turbulences occurred in July 2006.

Watai, T.; Hashida, G.; Yamanouchi, T.

2008-12-01

32

Sulphate profile in EPICA-DML ice core (Kohnen Station East Antarctica) by Fast Ion Chromatography.  

NASA Astrophysics Data System (ADS)

Kohnen Station (Dronning Maud Land - Atlantic sector of Antarctica) is one of the two drilling sites, the other being located at Dome C, chosen in the framework of EPICA project. Unlike Dome C ice core (EDC), where the low accumulation rate allowed recovering climatic and environmental data covering more than 800.000 years, the Kohnen Station ice core (EDML) is expected to provide paleo-data related to the last two glacial/interglacial cycles, due to the higher accumulation rate. On the other hand, the thicker annual accumulation rate grants a stratigraphy with higher temporal detail, providing more accurate information about fast climatic variations super-imposed to the major cycles. Moreover, EDML is expected to be influenced by Atlantic Ocean, then potentially able to give information about variations in the North Atlantic Deep Water and its relationship with global climate change. In order to temporally set the EDML paleo-records and allow a reliable synchronization with paleo-data memorised in Greenland and Antarctica ice cores, an accurate dating of the ice core is fundamental. The high accumulation rate and relative closeness to the sea drives toward the use of marine biogenic substances, irreversibly fixed in the snow layers as seasonal markers. Non-sea-salt sulphate coming from atmospheric oxidation of dimethylsulphide emitted by phytoplanktonic activity seems to be useful to this purpose. Since at Kohnen Station nss-sulphate is the dominant contribute to the sulphate budget, high-resolution sulphate profile could be used for a stratigraphic dating (summer maxima). An improvement of the FIC method, successfully used for in field measurement on EDC ice core, was performed. The method was applied to ice core processing at Bremerhaven (D) in June 2002 (113 to 449 m depth), giving a continuous sulphate record at 1.0 cm ice resolution, with a melting rate of 4.0 cm/min. The measured standard deviation is lower than 5.0 % and the detection limit is 4.0 ug/l. The data elaboration is in progress but preliminary results related to selected ice core sections seem to confirm a seasonal trend able to allow a reliable annual layer counting. Abrupt sulphate peaks, related to volcanic eruptions, superimposed to the seasonal trend, provide depth horizons for an absolute dating by knowing the event date or by comparing the same volcanic signatures recorded in already dated ice cores.

Severi, M.; Becagli, S.; Benassai, S.; Castellano, E.; Migliori, A.; Udisti, R.

2003-04-01

33

Streaky noise in seismic normal mode band observed at Syowa Station, Antarctica  

NASA Astrophysics Data System (ADS)

Background free oscillations are known as continuous and global signals on noise level in seismic normal mode band. These were found from record of superconducting gravimeter (SG) at Syowa Station, Antarctica in 1998 [Nawa et al. 1998], and then were confirmed at various sites. Other unknown slightly broad spectrum peaks were also found as streak on spectrogram of Syowa SG data in seismic normal mode band. But the feature is not found in gravimeter and seismometer records from any other sites, including IDA gravimeter record at SPA station, Antarctica. New SG (SG058), that is the third generation at Syowa Station, has started to observe since January 2010. The second generation SG (CT43, 2004-2009) had strong drift. The auxiliary barometer was less resolution (0.1 hPa) and its pressure record had a lot of steps and spikes occurring frequently by housing problem. To study in seismic normal mode band, high quality pressure data is needed to remove atmospheric pressure effect to gravity from SG data because a nominal admittance factor for its effect is -3 nm/s^2/hPa. The new barometer of SG058 system has a resolution of 0.001 hPa, and the housing problem has been fixed. In this study, we investigated the unknown streaky noise in seismic normal mode band using spectrograms of the new SG and other data observed at Syowa Station. The slightly broad spectrum peaks are clearly found at 2.5, 3.5, 7.6, 8.2 13.2, 16.7 mHz from the SG data during January - May 2010. Strength of these peaks shows time variation and it is not necessarily for phase to agree with each others. These unknown peaks are not intrinsic noise of the first generation SG (TT70, 1993 - 2003) but are local or regional signal (noise) around Syowa Station. The atmospheric pressure doesn’t have this steaky feature. The sea level variation causes noise level of Syowa SG data to be high by the effect of attraction and loading [Nawa et al. 2003]. Because the noise spectral peaks less than 3 mHz are removed by applying a transfer function method, it is reasonable to consider ocean variation as source of the streak at 2.5 mHz. Seismograms from the broad band seismometers (STS-1) at Syowa Station showed different features by its direction. The LHZ has similar feature with the SG. The LHE shows high noise level without peak. The LHN shows some weak streaks at different frequencies from LHZ and a streak of much strong spectral peak at 3.5 mHz. This strong wobble at 3.5 mHz should have different source from the other spectral peaks because its signal only is obtained from both in vertical and north-south direction. One of source candidate is wind. It tends to flow with constant direction in the Antarctic Continent. In that case, time variation of this streak might correspond with meteorological variation around Syowa Station.

Hayakawa, H.; Shibuya, K.; Doi, K.; Aoyama, Y.

2010-12-01

34

Measurement of black carbon at Syowa station, Antarctica: seasonal variation, transport processes and pathways  

NASA Astrophysics Data System (ADS)

Measurement of black carbon (BC) was carried out at Syowa station Antarctica (69° S, 39° E) from February 2004 until January 2007. The BC concentration at Syowa ranged from below detection to 176 ng m-3 during the measurements. Higher BC concentrations were observed mostly under strong wind (blizzard) conditions due to the approach of a cyclone and blocking event. The BC-rich air masses traveled from the lower troposphere of the Atlantic and Indian Oceans to Syowa (Antarctic coast). During the summer (November-February), the BC concentration showed a diurnal variation together with surface wind speed and increased in the katabatic wind from the Antarctic continent. Considering the low BC source strength in the Antarctic continent, the higher BC concentration in the continental air (katabatic wind) might be caused by long range transport of BC via the free troposphere from mid- and low- latitudes. The seasonal variation of BC at Syowa had a maximum in August, while at the other coastal stations (Halley, Neumayer, and Ferraz) and the continental station (Amundsen-Scott), the maximum occurred in October. This difference may result from different transport pathways and scavenging of BC by precipitation during the transport from the source regions. During the austral summer, long-range transport of BC via the free troposphere is likely to make an important contribution to the ambient BC concentration. The BC transport flux indicated that BC injection into the Antarctic region strongly depended on the frequency of storm (blizzard) conditions. The seasonal variation of BC transport flux increased by 290 mg m-2 month-1 in winter-spring when blizzards frequently occurred, whereas the flux decreased to lower than 50 mg m-2 month-1 in the summer with infrequent blizzards.

Hara, K.; Osada, K.; Yabuki, M.; Hayashi, M.; Yamanouchi, T.; Shiobara, M.; Wada, M.

2008-05-01

35

Comprehensive characterization report on Winter Quarters Bay, McMurdo Station, Antarctica  

SciTech Connect

Winter Quarters Bay is a small embayment located adjacent to the United States largest base in Antarctica, McMurdo Station. McMurdo Station, which is managed by the National Science Foundation`s Office of Polar Programs, was constructed in 1955, has been in constant use since that time, and has a population of about 1,000 persons during the summer and about 250 people for the winter. The bay offers shelter for ships and an ice dock is used during January and February to off load fuel and cargo. During earlier times, trash from the McMurdo Station was piled on the steep shoreline of the bay, doused with several thousand gallons of fuel and ignited. That practice has ceased and the site has been regraded to cover the waste. The bottom of the bay is littered with drums, equipment, tanks, tires, all sorts of metal objects, cables, etc., especially the southeastern side where dumping took place. The sediments are gravel in some places yet fine and fluid at other sites with coarse particles intermixed. The original benthic community is not well recorded but significant ecological changes have occurred. Sediments are contaminated with PCBs, metals, and hydrocarbon fuels. This report summarizes available information on Winter Quarters Bay and was originally intended to be used by workshop participants to become familiar with the bay prior to becoming updated with unpublished data by various Antarctic investigators. The proposed workshop was to assist the National Science Foundation in determining whether and how the bay should be remediated and to develop an integrated research plan if additional data were needed. However, plans changed, the workshop was never conducted, but the briefing report was prepared. Most of this report reviews and summarizes other published data. The only new data are those from the Idaho National Engineering and Environmental Laboratory`s investigation into the distribution of organic contaminants in the bay and sediment toxicity testing.

Crockett, A.B.; White, G.J.

1997-01-01

36

18 years of Energy Balance Observations on Antarctica using Automatic Weather Stations  

NASA Astrophysics Data System (ADS)

Since 1995, the Institute for Marine and Atmospheric research, Utrecht (IMAU) operates Automatic Weather Stations (AWS) on Antarctica. A total of 17 stations of which three located on the Larsen ice shelf, one on Berkner Island, and 13 in Dronning Maud Land (DML), are or have been operational. The obtained records are fairly complete and between 4 and 14 years long. The observed quantities include air temperature, relative humidity, wind speed, air pressure and incoming and outgoing short- and longwave radiation. These data are used to calculate the surface turbulent heat fluxes and study the temporal and spatial variability of meteorological quantities and the surface energy budget. The turbulent heat fluxes are calculated using the aerodynamic 'bulk' method between a single AWS sensor level and the surface, where the surface temperature is calculated using a surface energy balance closure assumption for a surface skin layer. At all sites the annual mean net radiation is negative and the near-surface air is on average stably stratified. The negative net radiative flux is largely balanced by a positive sensible heat flux. The latent heat flux is on average small and negative indicating a small net mass loss through sublimation. The spatial variations reflect differences in elevation, cloud cover and wind speed. The temporal variability on annual time scales is fairly similar from site to site. The three sites with the longest records (>8 years) show an increase in annual average temperature. The largest temperature change occurs in DML on the Plateau. For this station the annual mean fluxes also show a trend towards less negative net radiation, smaller sensible heat flux and larger latent heat flux. However, these trends are not significant.

Reijmer, Carleen; Van den Broeke, Michiel; Smeets, Paul; Boot, Wim

2013-04-01

37

Simultaneous aerosol measurements of unusual aerosol enhancement in troposphere over Syowa Station, Antarctica  

NASA Astrophysics Data System (ADS)

Unusual aerosol enhancement is often observed at Syowa Station, Antarctica during winter through spring. Simultaneous aerosol measurements near the surface and in the upper atmosphere were conducted twice using a ground-based optical particle counter, a balloon-borne optical particle counter, and micro-pulse LIDAR (MPL) in August and September 2012. During 13-15 August, aerosol enhancement occurred immediately after a storm condition. A high backscatter ratio and aerosol concentrations were observed from the surface to ca. 2.5 km over Syowa Station. Clouds appeared occasionally at the top of aerosol-enhanced layer during the episode. Aerosol enhancement was terminated on 15 August by strong winds caused by a cyclone's approach. In the second case on 5-7 September, aerosol number concentrations in Dp > 0.3 ?m near the surface reached > 104 L-1 at about 15:00 UT on 5 September in spite of calm wind conditions, whereas MPL measurement exhibited aerosols were enhanced at about 04:00 UT at 1000-1500 m above Syowa Station. The aerosol enhancement occurred near the surface-ca. 4 km. In both cases, air masses with high aerosol enhancement below 2.5-3 km were transported mostly from the boundary layer over the sea-ice area. In addition, air masses at 3-4 km in the second case came from the boundary layer over the open-sea area. This air mass history strongly suggests that dispersion of sea-salt particles from the sea-ice surface contributes considerably to the aerosol enhancement in the lower free troposphere (about 3 km) and that the release of sea-salt particles from the ocean surface engenders high aerosol concentrations in the free troposphere (3-4 km).

Hara, K.; Hayashi, M.; Yabuki, M.; Shiobara, M.; Nishita-Hara, C.

2013-10-01

38

Validation of sprite-inducing cloud-to-ground lightning based on ELF observations at Syowa station in Antarctica  

Microsoft Academic Search

Waveform monitoring of ELF radio signals in the frequency range of 1–400Hz have been carried out on a routine basis at Syowa station (69.0°S, 39.6°E in geographic coordinates), Antarctica since February, 2000. The main purpose of these observations is to monitor global lightning activity and to locate lightning-induced sprites and elves. The ELF observation system consisting of two search coil

Mitsuteru Sato; Hiroshi Fukunishi; Masayuki Kikuchi; Hisao Yamagishi; Walter A Lyons

2003-01-01

39

Mesospheric CO above Troll station, Antarctica observed by a ground based microwave radiometer  

NASA Astrophysics Data System (ADS)

This paper presents mesospheric carbon monoxide (CO) data acquired by the ground-based microwave radiometer of the British Antarctic Survey (BAS radiometer) stationed at Troll station in Antarctica (72° S, 2.5° E, 1270 m a.s.l.). The dataset covers the period from February 2008 to January 2010, however, due to very low CO concentrations below approximately 80 km altitude in summer, profiles are only presented during the Antarctic winter. CO is measured for approximately 2 h each day and profiles are retrieved approximately every half hour. The retrieved profiles, covering the pressure range from 1 to 0.01 hPa (approximately 48 to 80 km), are compared to measurements from Microwave Limb Sounder on the Aura satellite (Aura/MLS) and Whole Atmosphere Community Climate Model with Specified Dynamics (SD-WACCM). This intercomparison reveals a low bias of 0.5 to 1 ppmv at 0.1 hPa (approximately 64 km) and 2.5 to 3.5 ppmv at 0.01 hPa (approximately 80 km) of the BAS microwave radiometer compared to both reference datasets. One explanation for this low bias could be the known high bias of MLS which is on the same order of magnitude. The ground based radiometer shows high and significant correlation (coefficients higher than 0.9/0.7 compared to MLS/SD-WACCM) at all altitudes compared with both reference datasets. The dataset can be accessed under http://dx.doi.org/10/mhq.

Straub, C.; Espy, P. J.; Hibbins, R. E.; Newnham, D. A.

2013-06-01

40

Dworkin and Casey on abortion.  

PubMed

This article responds to two important recent treatments of abortion rights. I will mainly discuss Ronald Dworkin's recent writings concerning abortion: his article "Unenumerated rights: whether and how Roe should be overruled," and his book Life's Dominion. In these writings Dworkin presents a novel view of what the constitutional and moral argument surronding abortion is really about. Both debates actually turn, he argues, on the question of how to interpret the widely shared idea that human life is sacred. At the heart of the abortion debate is the essentially religious notion that human life has value which transcends its value to any particular person; abortion is therefore at bottom a religious issue. Dworkin hopes to use this analysis to show that the religion clauses of the First Amendment provide a "textual home" for a woman's right to choose abortion. I wish to scrutinize this suggestion here; I want to probe the precise consequences for abortion rights of such an understanding of their basis. I will argue that the consequences are more radical than Dworkin seems to realize. The other work I will examine here is the important 1992 Supreme Court decision on abortion, Planned Parenthood v. Casey. The controlling opinion in that case, written jointly by Justices Kennedy, O'Connor, and Souter, strongly reaffirmed Roe v. Wade, but also upheld most of the provisions of a Pennsylvania statute that had mandated various restrictions on abortion. The justices' basis for upholding these restictions was their introduction of a new constitutional standard for abortion regulations, an apparently weaker standard than those that had governed previous Supreme Court abortion decisions. I think there is a flaw in Casey's new constitutional test for abortion regulations, and I will explain, when we turn to Casey, what it is and why it bears a close relation to Dworkin's reluctance to carry his argument as far as it seems to go. PMID:11660187

Stroud, Sarah

1996-01-01

41

Culturable bacterial diversity at the Princess Elisabeth Station (Utsteinen, Sør Rondane Mountains, East Antarctica) harbours many new taxa.  

PubMed

We studied the culturable heterotrophic bacterial diversity present at the site of the new Princess Elisabeth Station at Utsteinen (Dronning Maud Land, East Antarctica) before construction. About 800 isolates were picked from two terrestrial microbial mat samples after incubation on several growth media at different temperatures. They were grouped using rep-PCR fingerprinting and partial 16S rRNA gene sequencing. Phylogenetic analysis of the complete 16S rRNA gene sequences of 93 representatives showed that the isolates belonged to five major phyla: Actinobacteria, Bacteroidetes, Proteobacteria, Firmicutes and Deinococcus-Thermus. Isolates related to the genus Arthrobacter were the most prevalent whereas the genera Hymenobacter, Deinococcus, Cryobacterium and Sphingomonas were also recovered in high numbers in both samples. A total of 35 different genera were found, the majority of which has previously been reported from Antarctica. For the genera Aeromicrobium, Aurantimonas, Rothia, Subtercola, Tessaracoccus and Xylophilus, this is the first report in Antarctica. In addition, numerous potential new species and new genera were recovered; many of them currently restricted to Antarctica, particularly in the phyla Bacteroidetes and Deinococcus-Thermus. PMID:21501941

Peeters, Karolien; Ertz, Damien; Willems, Anne

2011-04-17

42

Polycyclic aromatic hydrocarbons in soil and surface marine sediment near Jubany Station (Antarctica). Role of permafrost as a low-permeability barrier  

Microsoft Academic Search

Although Antarctica is still considered as one of the most pristine areas of the world, the growing tourist and fisheries activities as well as scientific operations and their related logistic support are responsible for an increasing level of pollutants in this fragile environment. Soils and coastal sediments are significantly affected near scientific stations particularly by polycyclic aromatic hydrocarbons (PAHs). In

Antonio Curtosi; Emilien Pelletier; Cristian L. Vodopivez; Walter P. Mac Cormack

2007-01-01

43

Observed trends for CF 3-containing compounds in background air at Cape Meares, Oregon, Point Barrow, Alaska, and Palmer Station, Antarctica  

Microsoft Academic Search

The concentrations of CF3-containing compounds in archived air samples collected at Cape Meares, Oregon, from 1978 to 1997, at Point Barrow, Alaska, from 1995 to 1998, and at Palmer Station, Antarctica, from 1991 to 1997, were determined by high resolution gas chromatography and high resolution mass spectrometry. The CF3-containing compounds measured by this method and discussed here are: the perfluorinated

J. A Culbertson; J. M Prins; E. P Grimsrud; R. A Rasmussen; M. A. K Khalil; M. J Shearer

2004-01-01

44

Visible and near-ultraviolet spectroscopy at McMurdo Station, Antarctica. 6. Observations of BrO  

SciTech Connect

Observations of the evening twilight BrO abundance over McMurdo Station, Antarctica during austral spring, 1987, are described. The observed variation of the slant column abundance with increasing solar zenith angles suggests that most of the BrO is located near 15 km. The total vertical column abundance observed during 1 week of measurements yielded an average value of 2.5 {times} 10{sup 13} cm{sup {minus}2}, assuming the room temperature absorption cross sections measured by Cox et al. (1982). These values are consistent with BrO mixing ratios of about 5-15 parts per trillion by volume distributed from 150 to 20 mbar. If the differential absorption cross section of BrO increases by 30% at temperatures characteristic of the Antarctic lower stratosphere, as indicated by Sander and Watson (1981), then the BrO measurements reported in this paper should be decreased by 30%.

Carroll, M.A.; Solomon, S.; Schmeltekopf, A.L. (NOAA, Boulder, CO (United States)); Sanders, R.W. (Univ. of Colorado, Boulder (United States))

1989-11-30

45

Simultaneous PMC and PMSE observations with a ground-basedlidar and SuperDARN HF radar over Syowa Station, Antarctica  

NASA Astrophysics Data System (ADS)

A Rayleigh-Raman lidar system had been installed by the 52nd JapaneseAntarctic Research Expedition on February, 2011 at Syowa Station Antarctica(69.0°S, 39.5°E). Polar Mesospheric Cloud (PMC) was detected by the lidar at22:30UT (+3hr for LT) on Feb 4th, 2011, the first day of a routineoperation. This event is the first time to detect PMC over Syowa Station bya lidar. In the same night, SuperDARN HF radar with oblique incidence beamsalso detected Polar Mesosphere Summer Echoes (PMSEs) during 21:30UT to23:00UT. Although these signals were detected at different times andlocations, PMC motion estimated using horizontal wind velocities obtained bya collocated MF radar strongly suggests that they have a common origin (i.e.ice particle). We consider that this event occurred in the end of PMCactivity period at Syowa Station in the austral summer season (2010-2011),since the lidar did not detected any PMC signals on other days in February,2011. This is consistent with satellite-born PMC observations by AIM/CIPSand atmospheric temperature observations by AURA/MLS instruments.

Suzuki, Hidehiko; Nakamura, Takuji; Tsutsumi, Masaki; Kawahara, Takuya D.; Ogawa, Tadahiko; Tomikawa, Yoshihiro; Ejiri, Mitsumu K.; Sessai Yukimatu, Akira; Abo, Makoto

2012-07-01

46

Why Antarctica?  

NASA Astrophysics Data System (ADS)

The dry, cold, tenuous and stable air above the Antarctic Plateau provides superb conditions for the conduct of many classes of astronomical observations. We review in particular the rationale for undertaking near- IR, mm and particle astronomy in Antarctica, disciplines where telescopes are now operating at the US Amundsen-Scott South Pole Station.

Burton, M. G.

1996-01-01

47

Validation of sprite-inducing cloud-to-ground lightning based on ELF observations at Syowa station in Antarctica  

NASA Astrophysics Data System (ADS)

Waveform monitoring of ELF radio signals in the frequency range of 1-400Hz have been carried out on a routine basis at Syowa station (/69.0°S, /39.6°E in geographic coordinates), Antarctica since February, 2000. The main purpose of these observations is to monitor global lightning activity and to locate lightning-induced sprites and elves. The ELF observation system consisting of two search coil sensors (geomagnetic north-south (H) and east-west (D) sensors) was installed at a remote unmanned observatory in West Ongul Island located 5km southwest from Syowa station. As a back up system, the same system was installed near Syowa station in East Ongul Island. Signals from these sensors were digitally sampled at 1000Hz with a GPS time code. On July 4, 2000 during the STEPS (Severe Thunderstorm Electrification and Precipitation Studies) 2000 campaign carried out over the Great Plains in the US, 57 sprite events were observed from Yucca Ridge Field Station (/40.7°N, /104.9°W), Colorado, and 53 out of these sprite events had one-to-one correspondence to transient Schumann resonances (SR) detected at Syowa station. The waveforms of these SR are characterized by sharp initial pulses and following damped oscillations. The great circles representing the propagation paths are determined from the Lissojous plots of the H and D magnetic field data of the transient SR. It has been demonstrated that the minimum distance between the great circles and the locations of causative cloud-to-ground (CG) discharges is ~240km on average. It is thus concluded that the method to determine the propagation paths from Lissajous plots is extremely accurate when we use the Syowa ELF waveform data. Consequently, it would be possible to globally triangulate sprite-inducing CG locations by setting up at least one more observation site with the same system.

Sato, Mitsuteru; Fukunishi, Hiroshi; Kikuchi, Masayuki; Yamagishi, Hisao; Lyons, Walter A.

2003-03-01

48

Atmospheric ozone above Troll station, Antarctica observed by a ground based microwave radiometer  

NASA Astrophysics Data System (ADS)

This paper describes the stratospheric and mesospheric ozone profiles retrieved from spectral measurements of the 249.96 GHz O3 line, using the British Antarctic Survey's ground-based Microwave Radiometer at Troll (BAS-MRT), Antarctica (72°01' S, 02°32' E, 62° Mlat). The instrument operated at Troll from February 2008 through January 2010, and hourly averaged spectra were used to retrieve approximately 22 ozone profiles per day. The ozone profiles cover the pressure range from 3 to 0.02 hPa (approximately 38 to 72 km) which includes the topside of the stratospheric ozone layer and the peak of the tertiary maximum. Comparing the retrieved ozone volume mixing ratio (vmr) values to Aura/MLS and SD-WACCM shows no significant bias to within the instrumental uncertainties. The long-term variations (> 20 days) between MLS and SD-WACCM agree well with BAS-MRT at all altitudes with significant correlation coefficients of at least 0.9 (0.7 with SD-WACCM) in the upper stratosphere and middle mesosphere. A weaker correlation is found for the long-term variations in summer when most of the vmr values are below the random noise level of Aura/MLS. The correlation of short-term variations (< 20 days) between MLS and BAS-MRT agree well at all altitudes with significant correlation coefficients of at least 0.7 in the upper stratosphere and middle mesosphere. The ozone profiles retrieved at Troll, Antarctica extend the sparse data coverage of middle atmospheric ozone above Antarctica, where, due to the dynamic nature of the ozone concentrations, systematic observations with a high temporal resolution are desirable. The O3 profiles presented here are stored at the UK's Polar Data Centre (http://doi.org/nc3) and are available for public scientific use.

Daae, M.; Straub, C.; Espy, P. J.; Newnham, D. A.

2013-09-01

49

Sulfur and Oxygen Isotopic Composition of Sulfate in the Fresh Water, King Sejong Station, King George Island, Antarctica  

NASA Astrophysics Data System (ADS)

Isotopic compositions of sulfur (?34S) and oxygen (?18O) were measured for the sulfate of the fresh water near the King Sejong Station, King George Island, Antarctica. Sejong station is located in the Barton peninsular of the King George Island. The geology around King Sejong station mainly composed of basalt-andesite, quart monzodiorite, and granodiorite. Lapilli tuff, conglomerate, sandstone, and siltstone occur along the southern and eastern shore of the Barton peninsula. Lapilli tuff also occurs on the highland located on southeastern part of the Barton peninsula. The ?34S values of sulfate extracted from fresh water samples at King Sejong Station range from 13.7 to 16.3 per mil excluding 1 sample. These sulfur values are very narrow in their range compared with those from anthropogenic sources. These sulfur values are 5 to 7 per mil lower than those of typical present seawater. Considering the rocks occurring near the King Sejong station, these sulfur isotopic values do not seem to be related to any evaporites of certain age. In Antarctic region the natural source of sulfate dissolved in water could be originated from marine biogenic source (DMS), sea-salt, volcanic source, or other continental sources. Most of the ?34S values of sulfate at King Sejong station seems to indicate the dominance of marine biogenic origin for the source of sulfur. The ?18O values of sulfate extracted from fresh water samples at King Sejong Station range from 1.9 to 6.4 per mil excluding 1 sample. These oxygen isotope values are lower than those of the sulfate in the present seawater by 6 per mil. However, both sulfur and oxygen isotope values strongly represent the influence of the seawater sulfate. One sample have 2.6 and -1.1 per mil in its ?34S and ?18O values, respectively, that are quite different from the isotopic values of other samples. This sample was collected in the highland far from the King Sejong station. Therefore this sample might reflect the composition of rather pure precipitation not affected by seawater sulfate. The atmospheric deposition might have been the major source of dissolved sulfate but it is not clear whether the source materials are from natural and/or anthropogenic origin.

Kim, M.; Lee, I.; Lee, J.; Park, B.; Mayer, B.; Kaufman, A. J.; Park, S.; Kim, G.; Lee, K.

2008-12-01

50

Reading Casey: Structuring the Woman's Decisionmaking Process  

Microsoft Academic Search

In this Article, Professor Goldstein argues that the primary concerns of Planned Parenthood v. Casey's joint opinion were expressive, not regulatory, in nature: to allow the state more leeway to structure the woman's decisionmaking process and to engage in its own speech regarding her exercise of her procreative choice. To this end, he identifies three models by which the state

Robert D. Goldstein

1996-01-01

51

Analysis of Background Seismic Noise Recorded at the Amundsen-Scott South Pole Station, Antarctica  

NASA Astrophysics Data System (ADS)

A small array of high frequency seismometers was recently placed around the Amundsen-Scott South Pole Station in order to characterize seismic noise generated by the station during operations. This week long experiment, titled, "South Pole Analysis of Machines" or SPAM was conducted in January of 2006 using equipment provided by IRIS PASSCAL to sample the high frequency noise sources generated at the NSF's research base. These data will be correlated to those observed at the ultra quiet GSN seismic station (QSPA) located 5 miles from the base. The purpose of the experiment is to show that although the QSPA sensors are 5 miles away and nearly 1000 feet deep in the ice, there is still a risk of contamination of the signals by cultural noise from the South Pole research base. A Quiet Sector was established around the QSPA station in order to minimize vibrational noise sources, but there is interest in moving some experiments out into the Quiet Sector. Characterizing the noise sources will help us determine the potential reduction in data quality expected at the QSPA station as experiments move closer to the site. Sensors were placed next to the power generators, aircraft taxiway, large antenna towers, as well as at the base of the new station itself. Sensors were also placed between the research base and the QSPA station to get an idea of the propagation of the noise toward the QSPA station. Several high frequency noise sources are clearly seen on all array elements with a number of very clear spectral lines above 1 Hz. These are primarily associated with snow moving tractors and power generators. Smaller signals are seen that may be related to wind loading on the new South Pole elevated station along with harmonics that appear to be correlated with large air handling equipment in the station. Also evident are air operations with landings, takeoffs, taxi and idling C-130's evident. Although greatly attenuated, almost all of these signals are observed at the QSPA station. Therefore, encroachment of any of these noise sources into the Quiet Sector will adversely affect the signal-to-noise ratio in the frequencies above 1 Hz for seismograms recorded at QSPA. At this point, QSPA is by far the quietest seismic station in the world at these high frequencies. We hope that we can preserve these low background noise levels and keep the QSPA one of the quietest places on Earth.

Anderson, K. R.; Aster, R.; Beaudoin, B. C.; Butler, R.

2006-12-01

52

Glacio-meteorological conditions in the vicinity of the Belgian Princess Elisabeth Station, Antarctica  

Microsoft Academic Search

During two consecutive reconnaissance surveys in 2004 and 2005 and a revisit in 2008, the glaciological and meteorological conditions of the vicinity of the new Belgian Princess Elisabeth Station (71°57'S; 23°20'E) on Utsteinen Ridge were investigated. We set up an automatic weather station, measured the ice thickness around the Utsteinen Ridge, and established a stake network. Results of these baseline

FRANK PATTYN; KENICHI MATSUOKA; JOHAN BERTE

2009-01-01

53

Glacio-meteorological conditions in the vicinity of the Belgian Princess Elisabeth Station, Antarctica  

NASA Astrophysics Data System (ADS)

During two consecutive reconnaissance surveys in 2004 and 2005 and a revisit in 2008, the glaciological and meteorological conditions of the vicinity of the new Belgian Princess Elisabeth Station (71°57'S; 23°20'E) on Utsteinen Ridge were investigated. We set up an automatic weather station, measured the ice thickness around the Utsteinen Ridge, and established a stake network. Results of these baseline investigations show that Utsteinen Ridge is a sheltered spot from the main katabatic winds and that also during the winter months, air temperatures are rather mild and witness the coreless winter. Mass balance is generally low (near zero) with accumulation to the east and relatively small ablation to the west of Utsteinen Ridge. Ice flow in the vicinity of the station is also minimal, since the Sor Rondane Mountains upstream of the station block most of the ice flow, a feature that is most apparent in the area where the station is situated. Measurements of the surface topography separated by four years show that the construction of the station seems to have a limited effect on the redistribution of snow around it.

Pattyn, F.; Matsuoka, K.; Berte, J.

2009-04-01

54

Tethered balloon-borne aerosol measurements: seasonal and vertical variations of aerosol constituents over Syowa Station, Antarctica  

NASA Astrophysics Data System (ADS)

Tethered balloon-borne aerosol measurements were conducted at Syowa Station, Antarctica during the 46th Japanese Antarctic expedition (2005-2006). Direct aerosol sampling was operated from near the surface to the lower free troposphere (approximately 2500 m) using a balloon-borne aerosol impactor. Individual aerosol particles were analyzed using a scanning electron microscope equipped with an energy dispersive X-ray spectrometer. Seasonal and vertical features of aerosol constituents and their mixing states were investigated. Results show that sulfate particles were dominant in the boundary layer and lower free troposphere in the summer, whereas sea-salt particles were dominant during winter-spring. Minerals, MgSO4, and sulfate containing K were identified as minor aerosol constituents in both boundary layer and free troposphere over Syowa Station. Although sea-salt particles were dominant during winter-spring, the relative abundance of sulfate particles increased in the boundary layer when air masses fell from the free troposphere over the Antarctic coast and continent. Sea-salt particles were modified considerably through heterogeneous reactions with SO42-, CH3SO3-, and their precursors during the summer, and were modified slightly through heterogeneous reactions with NO3- and its precursors. During winter-spring, sea-salt modification was insignificant, particularly in the cases of high relative abundance of sea-salt particles and higher number concentrations. In August, NO3- and its precursors contributed greatly to sea-salt modification over Syowa Station. Because of the occurrence of sea-salt fractionation on sea-ice, Mg-rich sea-salt particles were identified during April-November. In contrast, Mg-free sea-salt particles and slightly Mg-rich sea-salt particles co-existed in the lower troposphere during summer. Thereby, Mg separation can proceed by sea-salt fractionation during summer in Antarctic regions.

Hara, K.; Osada, K.; Yamanouchi, T.

2013-03-01

55

Tethered balloon-borne aerosol measurements: seasonal and vertical variations of aerosol constituents over Syowa Station, Antarctica  

NASA Astrophysics Data System (ADS)

Tethered balloon-borne aerosol measurements were conducted at Syowa Station, Antarctica, during the 46th Japanese Antarctic expedition (2005-2006). Direct aerosol sampling was operated from near the surface to the lower free troposphere (approximately 2500 m) using a balloon-borne aerosol impactor. Individual aerosol particles were analyzed using a scanning electron microscope equipped with an energy dispersive X-ray spectrometer. Seasonal and vertical features of aerosol constituents and their mixing states were investigated. Results show that sulfate particles were predominant in the boundary layer and lower free troposphere in summer, whereas sea-salt particles were predominant during winter through spring. Minerals, MgSO4, and sulfate containing K were identified as minor aerosol constituents in both boundary layer and free troposphere over Syowa Station. Although sea-salt particles were predominant during winter through spring, the relative abundance of sulfate particles increased in the boundary layer when air masses fell from the free troposphere over the Antarctic coast and continent. Sea-salt particles were modified considerably through heterogeneous reactions with SO42- CH3SO3- and their precursors during summer, and were modified slightly through heterogeneous reactions with NO3- and its precursors. During winter through spring, sea-salt modification was insignificant, particularly in the cases of high relative abundance of sea-salt particles and higher number concentrations. In August, NO3- and its precursors contributed greatly to sea-salt modification over Syowa Station. Because of the occurrence of sea-salt fractionation on sea ice, Mg-rich sea-salt particles were identified during the months of April through November. In contrast, Mg-free sea-salt particles and slightly Mg-rich sea-salt particles coexisted in the lower troposphere during summer. Thereby, Mg separation can proceed by sea-salt fractionation during summer in Antarctic regions.

Hara, K.; Osada, K.; Yamanouchi, T.

2013-09-01

56

Visible and near-ultraviolet spectroscopy at McMurdo Station, Antarctica 10. Reductions of stratospheric NO2 due to Pinatubo aerosols  

Microsoft Academic Search

Visible absorption spectroscopy was employed for stratospheric measurements at McMurdo Station, Antarctica, during the summer and fall seasons in 1990, 1991, 1992, and 1993. Observed column amounts of NO2 were as much as 50% smaller in 1992 and 1993 than in 1990 and 1991. The measured decreases in NO2 are believed to be due to the hydrolysis of N2O5 on

S. Solomon; R. W. Sanders; R. O. Jakoubek; K. H. Arpag; S. L. Stephens; J. G. Keys; R. R. Garcia

1994-01-01

57

Visible and near-ultraviolet spectroscopy at McMurdo Station, Antarctica. VIII - Observations of nighttime NO2 and NO3 from April to October 1991  

Microsoft Academic Search

Lunar absorption spectra have been used to determine the vertical column abundances of NO2 and NO3 above McMurdo Station, Antarctica, during the fall, winter, and spring seasons in 1991. The observed nighttime NO2 and NO3 amounts during the fall and spring were broadly consistent with model predictions and with daytime measurements. During winter, local photochemistry would imply a long polar

S. Solomon; J. P. Smith; R. W. Sanders; L. Perliski; H. L. Miller; G. H. Mount; J. G. Keys; A. L. Schmeltekopf

1993-01-01

58

Seasonal variations in the horizontal wind structure from 0 100 km above Rothera station, Antarctica (67° S, 68° W)  

NASA Astrophysics Data System (ADS)

A medium frequency spaced-antenna radar has been operating at Rothera station, Antarctica (67° S, 68° W) for two periods, between 1997-1998 and since 2002, measuring winds in the mesosphere and lower thermosphere. In this paper monthly mean winds are derived and presented along with three years of radiosonde balloon data for comparison with the HWM-93 model atmosphere and other high latitude southern hemisphere sites. The observed meridional winds are slightly more northwards than those predicted by the model above 80 km in the winter months and below 80 km in summer. In addition, the altitude of the summer time zero crossing of the zonal winds above the westward jet is overestimated by the model by up to 8 km. These data are then merged with the wind climatology obtained from falling sphere measurements made during the PORTA campaign at Rothera in early 1998 and the HWM-93 model atmosphere to generate a complete zonal wind climatology between 0 and 100 km as a benchmark for future studies at Rothera. A westwards (eastwards) maximum of 44 ms-1 at 67 km altitude occurs in mid December (62 ms-1 at 37 km in mid July). The 0 ms-1 wind contour reaches a maximum altitude of 90 km in mid November and a minimum altitude of 18 km in January extending into mid March at 75 km and early October at 76 km.

Hibbins, R. E.; Shanklin, J. D.; Espy, P. J.; Jarvis, M. J.; Riggin, D. M.; Fritts, D. C.; Lübken, F.-J.

2005-07-01

59

Seasonal variations in the horizontal wind structure from 0-100 km above Rothera station, Antarctica (67° S, 68° W)  

NASA Astrophysics Data System (ADS)

A medium frequency spaced-antenna radar has been operating at Rothera station, Antarctica (67° S, 68° W) for two periods, between 1997-1998 and since 2002, measuring winds in the mesosphere and lower thermosphere. In this paper monthly mean winds are derived and presented along with three years of radiosonde balloon data for comparison with the HWM-93 model atmosphere and other high latitude southern hemisphere sites. The observed meridional winds are slightly more northwards than those predicted by the model above 80 km in the winter months and below 80 km in summer. In addition, the altitude of the summer time zero crossing of the zonal winds above the westward jet is overestimated by the model by up to 8 km. These data are then merged with the wind climatology obtained from falling sphere measurements made during the PORTA campaign at Rothera in early 1998 and the HWM-93 model atmosphere to generate a complete zonal wind climatology between 0 and 100 km as a benchmark for future studies at Rothera. A westwards (eastwards) maximum of 44 ms-1 at 67 km altitude occurs in mid December (62 ms-1 at 37 km in mid July). The 0 ms-1 wind contour reaches a maximum altitude of 90 km in mid November and a minimum altitude of 18 km in January extending into mid March at 75 km and early October at 76 km.

Hibbins, R. E.; Shanklin, J. D.; Espy, P. J.; Jarvis, M. J.; Riggin, D. M.; Fritts, D. C.; Lübken, F.-J.

2005-11-01

60

Observations of Earth space by self-powered stations in Antarctica  

NASA Astrophysics Data System (ADS)

Coupling of the solar wind to the Earth magnetosphere/ionosphere is primarily through the high latitude regions, and there are distinct advantages in making remote sensing observations of these regions with a network of ground-based observatories over other techniques. The Antarctic continent is ideally situated for such a network, especially for optical studies, because the larger offset between geographic and geomagnetic poles in the south enables optical observations at a larger range of magnetic latitudes during the winter darkness. The greatest challenge for such ground-based observations is the generation of power and heat for a sizable ground station that can accommodate an optical imaging instrument. Under the sponsorship of the National Science Foundation, we have developed suitable automatic observing platforms, the Automatic Geophysical Observatories (AGOs) for a network of six autonomous stations on the Antarctic plateau. Each station housed a suite of science instruments including a dual wavelength intensified all-sky camera that records the auroral activity, an imaging riometer, fluxgate and search-coil magnetometers, and ELF/VLF and LM/MF/HF receivers. Originally these stations were powered by propane fuelled thermoelectric generators with the fuel delivered to the site each Antarctic summer. A by-product of this power generation was a large amount of useful heat, which was applied to maintain the operating temperature of the electronics in the stations. Although a reasonable degree of reliability was achieved with these stations, the high cost of the fuel air lift and some remaining technical issues necessitated the development of a different type of power unit. In the second phase of the project we have developed a power generation system using renewable energy that can operate automatically in the Antarctic winter. The most reliable power system consists of a type of wind turbine using a simple permanent magnet rotor and a new type of power control system with variable resistor shunts to regulate the power and dissipate the excess energy and at the same time provide heat for a temperature controlled environment for the instrument electronics and data system. We deployed such systems and demonstrated a high degree of reliability in several years of operation in spite of the relative unpredictability of the Antarctic environment. Sample data are shown to demonstrate that the AGOs provide key measurements, which would be impossible without the special technology developed for this type of observing platform.

Mende, S. B.; Rachelson, W.; Sterling, R.; Frey, H. U.; Harris, S. E.; McBride, S.; Rosenberg, T. J.; Detrick, D.; Doolittle, J. L.; Engebretson, M.; Inan, U.; Labelle, J. W.; Lanzerotti, L. J.; Weatherwax, A. T.

2009-12-01

61

Observations of Earth space by self-powered stations in Antarctica.  

PubMed

Coupling of the solar wind to the Earth magnetosphere/ionosphere is primarily through the high latitude regions, and there are distinct advantages in making remote sensing observations of these regions with a network of ground-based observatories over other techniques. The Antarctic continent is ideally situated for such a network, especially for optical studies, because the larger offset between geographic and geomagnetic poles in the south enables optical observations at a larger range of magnetic latitudes during the winter darkness. The greatest challenge for such ground-based observations is the generation of power and heat for a sizable ground station that can accommodate an optical imaging instrument. Under the sponsorship of the National Science Foundation, we have developed suitable automatic observing platforms, the Automatic Geophysical Observatories (AGOs) for a network of six autonomous stations on the Antarctic plateau. Each station housed a suite of science instruments including a dual wavelength intensified all-sky camera that records the auroral activity, an imaging riometer, fluxgate and search-coil magnetometers, and ELF/VLF and LM/MF/HF receivers. Originally these stations were powered by propane fuelled thermoelectric generators with the fuel delivered to the site each Antarctic summer. A by-product of this power generation was a large amount of useful heat, which was applied to maintain the operating temperature of the electronics in the stations. Although a reasonable degree of reliability was achieved with these stations, the high cost of the fuel air lift and some remaining technical issues necessitated the development of a different type of power unit. In the second phase of the project we have developed a power generation system using renewable energy that can operate automatically in the Antarctic winter. The most reliable power system consists of a type of wind turbine using a simple permanent magnet rotor and a new type of power control system with variable resistor shunts to regulate the power and dissipate the excess energy and at the same time provide heat for a temperature controlled environment for the instrument electronics and data system. We deployed such systems and demonstrated a high degree of reliability in several years of operation in spite of the relative unpredictability of the Antarctic environment. Sample data are shown to demonstrate that the AGOs provide key measurements, which would be impossible without the special technology developed for this type of observing platform. PMID:20059157

Mende, S B; Rachelson, W; Sterling, R; Frey, H U; Harris, S E; McBride, S; Rosenberg, T J; Detrick, D; Doolittle, J L; Engebretson, M; Inan, U; Labelle, J W; Lanzerotti, L J; Weatherwax, A T

2009-12-01

62

Soil formation in coastal continental Antarctica (Wilkes Land)  

Microsoft Academic Search

Recent antarctic soil studies suggest that in terrestrial ecosystems of coastal regions soil formation and chemical weathering occur to a greater extent than predicted by former models. This paper summarizes pedogenic findings from the Casey area on the coast of East Antarctica and presents a proposal of soil formation sequences on a large-scale data base. Soil organic matter accumulation and

Lothar Beyer; Kristina Pingpank; Gunther Wriedt; Manfred Bölter

2000-01-01

63

Broad-band seismometers in the extreme cold: what we learn from the observatory station CCD (Concordia, Antarctica)  

NASA Astrophysics Data System (ADS)

The seismological station CCD, located at Concordia (Dome C, East Antarctica) has been continuously operating since the year-round opening of the base in 2005. For the first two years, technical problems due to the extreme cold conditions (the seismic vault is at a constant temperature of -54°C) resulted in data whose quality was too poor to permit distribution. Since January 2007, after significant improvements, the data from CCD have been officially open to public distribution upon request to the operators. However, up to 2010, we have only been able to provide nominal seismometer responses along with the data, despite suspecting that the extreme cold could affect the characteristics of the instruments. Several attemps were made during the summer campaigns of 2008, 2009 and 2010 to perform an in situ calibration of the instruments, but were unsuccessful for various reasons, and finally, the first results came from the calibrations made in early 2011. Two instruments were calibrated in 2011: an STS-2 running at -30°C (heated to come closer to the instrument specifications), and a T240 running at the ambient temperature of -54°C. We have found the response of the «warm» STS-2 to be near nominal, while that of the «cold T240» differs substantially from its nominal response. Furthermore, during the time period 2007-2009, the «warm» STS-2 was running alongside an identical but unheated STS-2, for which we attempted to make a relative calibration. Due to the much smaller excitation provided by natural signals, this relative calibration is by far less precise than a true active one, and does not provide reliable instrumental constants. However, no evidence was found for significant differences between the heated and non-heated STS2 seismometers. In January 2012, a second set of in situ calibrations was performed, whose results will also be presented here.

Lévêque, J.-J.; Bès de Berc, M.; Maggi, A.; Thoré, J.-Y.

2012-04-01

64

Airborne Radar Sounding Studies of a Subglacial "Lake" Near South Pole Station, Antarctica  

NASA Astrophysics Data System (ADS)

Radar ice sounding transects have revealed what appears to be a subglacial lake beneath 2800 meters of ice 10.5 kilometers from the South Pole. It has been proposed that sterile drilling be tested at this lake, a location accessible from the existing South Pole Station. Not only would this allow for techniques to be tested before risking contamination of Lake Vostok, but there is also the possibility of finding exotic microorganisms in a permafrost-like bed. Other workers have concluded that the lake is frozen by analyzing temperature measurements in the South Pole ice and extrapolating a base temperature at the "lake" using several different models. Here, we attempt to determine the material of the lake by extracting its properties through a complete solution to the radar equation. The radar equation accounts for all the factors that influence the returned echo strength, including radar system parameters and propagation effects. The largest unknown quantity is the ice loss, which depends on the temperature and impurities throughout the ice. For this analysis, we use temperature profiles corresponding to both a frozen and a liquid base and several possible dielectric loss models to compute ice loss. The strength of the returned echo is also affected by the material making up the "lake" and its roughness. The reflection coefficients calculated for a temperature profile allowing melt are not consistent with a glacier/liquid-water interface, thus implying that this "lake" is indeed frozen. Further analysis of the reflection coefficients indicates that they correspond to impure ice, and local topography suggests that this feature is possibly an ancient lake.

Lindzey, L. E.; Blankenship, D. D.; Peters, M. E.

2003-12-01

65

Welcome to Antarctica!  

NSDL National Science Digital Library

This site provides a virtual tour of Antarctica and the Amundsen-Scott research station at the South Pole. The tour begins in New Zealand and goes to the station at McMurdo on the coast of Antarctica and finally to the center of the continent and the South Pole. Photos accompanied by brief captions are provided of scenes along the tour route. Users can also go directly to McMurdo or the South Pole, use a site map for the tour, or use a search engine.

66

Soviet Medical Research in Antarctica.  

National Technical Information Service (NTIS)

Contents: Peculiarities of the course of reparative processes in Antarctica; Changes in the cardiovascular system in personnel of high-altitude stations and participants in sled-tractor expeditions; Experience of medical services at the transcontinental s...

G. A. Barashkov I. V. Shastin N. V. Bystrov

1969-01-01

67

Seasonal variation of upper mesospheric temperatures from the OH and O2 nightglow over King Sejong Station, Antarctica  

Microsoft Academic Search

A spectral airglow temperature imager SATI was operated at King Sejong Station 62 22 r S 301 2 r E Korea Antarctic Research Station during a period of 2002 - 2005 Rotational temperatures from the OH 6-2 and O 2 0-1 band airglow were obtained for more than 600 nights during the 4 year operation Both the OH and O

J.-H. Kim; Y. H. Kim; B.-K. Moon; J.-K. Chung; Y.-I. Won

2006-01-01

68

Occurrence of microbial indicators and Clostridium perfringens in wastewater, water column samples, sediments, drinking water, and Weddell seal feces collected at McMurdo Station, Antarctica.  

PubMed

McMurdo Station, Antarctica, has discharged untreated sewage into McMurdo Sound for decades. Previous studies delineated the impacted area, which included the drinking water intake, by using total coliform and Clostridium perfringens concentrations. The estimation of risk to humans in contact with the impacted and potable waters may be greater than presumed, as these microbial indicators may not be the most appropriate for this environment. To address these concerns, concentrations of these and additional indicators (fecal coliforms, Escherichia coli, enterococci, coliphage, and enteroviruses) in the untreated wastewater, water column, and sediments of the impacted area and drinking water treatment facility and distribution system at McMurdo Station were determined. Fecal samples from Weddell seals in this area were also collected and analyzed for indicators. All drinking water samples were negative for indicators except for a single total coliform-positive sample. Total coliforms were present in water column samples at higher concentrations than other indicators. Fecal coliform and enterococcus concentrations were similar to each other and greater than those of other indicators in sediment samples closer to the discharge site. C. perfringens concentrations were higher in sediments at greater distances from the discharge site. Seal fecal samples contained concentrations of fecal coliforms, E. coli, enterococci, and C. perfringens similar to those found in untreated sewage. All samples were negative for enteroviruses. A wastewater treatment facility at McMurdo Station has started operation, and these data provide a baseline data set for monitoring the recovery of the impacted area. The contribution of seal feces to indicator concentrations in this area should be considered. PMID:15574926

Lisle, John T; Smith, James J; Edwards, Diane D; McFeters, Gordon A

2004-12-01

69

Visible and near-ultraviolet spectroscopy at McMurdo Station, Antarctica 8. Observations of nighttime NO[sub 2] and NO[sub 3] from April to October 1991  

Microsoft Academic Search

Lunar absorption spectra have been used to determine the vertical column abundances of NO[sub 2] and NO[sub 3] above McMurdo Station, Antarctica (77.8[degrees]S), during the fall, winter, and spring seasons in 1991. The observed nighttime NO[sub 2] and NO[sub 3] amounts during the fall and spring were broadly consistent with model predictions and with daytime measurements. During winter, local photochemistry

S. Solomon; R. W. Sanders; G. H. Mount; J. P. Smith; L. Perliski; H. L. Miller; J. G. Keys; A. L. Schmeltekopf

1993-01-01

70

Casey and the resuscitation of Roe v. Wade.  

PubMed

Casey v. Planned Parenthood Association of Southeastern Pennsylvania, 60 U.S. 4795 (1992) is a great victory for procreative liberty. The US Supreme Court reaffirmed the principe of Roe v. Wade, 410 U.S. 113 (1973): a women has a right to terminate a pregnancy up until viability, and thereafter when necessary to protect her life or health. The decision allows the states to impose regulations insuring that abortion decisions are "thoughtful and informed," provided they do not impose an "undue burden," a change from Roe where early pregnancy regulations were permitted only when the state had a compelling interest. In Casey, the Court's perception of its legitimacy and its reliance on stare decisis left intact the substantive due process line of cases establishing the privacy interest related to marriage, procreation, contraception, family relationships, childbearing, and education, reaffirming its authority to define fundamental unenumerated rights through "reasoned judgment" in interpreting the liberty clause of the 14th Amendment. Casey leaves the US with the most liberal system in the world, but the issue is unnecessarily politicized because constitutionalizing the issue has removed almost all ability for compromise. If the federal Freedom of Choice Act is defeated, Casey may provide the vehicle for a compromise. The affirmation of abortion presents the possibility that the manufacturer of the contragestive drug RU 486 will lift its self-imposed prohibition against marketing RU 486 in US. Casey sympathetically describes the choice facing a pregnant woman and explicitly sees abortion as a quintessential issue of women's rights. "Her suffering is too intimate and personal for the State to insist, without more, upon its own vision of the woman's role, however dominant that vision has been in the course of our history and our culture." PMID:1428831

Robertson, J A

71

The role of sublimation and condensation in the formation of ice sheet surface at Mizuho Station, Antarctica  

Microsoft Academic Search

Three methods were used to determine the sublimation and condensation at Mizuho Station in 1977-1978, that is, direct observations with an evaporimeter filled with ice and repeated measurements of offset stakes and indirect estimation using an empirical formula derived from meteorological parameters. A comparison of three methods shows satisfactory agreement, especially in the weekly average of sublimation in the 1977-1978

Yoshiyuki Fujii; Kou Kusunoki

1982-01-01

72

Biologically effective ultraviolet radiation, total ozone abundance, and cloud optical depth at McMurdo Station, Antarctica, September 15 1988 through April 15 1989  

SciTech Connect

Spectral measurements of solar ultraviolet (UV) radiation taken at McMurdo Station, Antarctica are used to determine biologically effective UV dose, ozone column content, and effective cloud optical depth. The seasonal variation in these parameters from September 15, 1988 through April 15, 1989 is presented and discussed. Although no days from September 15 through October experienced UV dose exceeding that occurring at summer solstice, the temporal variation in the level of UV radiation is markedly asymmetric with respect to summer solstice. A general enhancement by about 20% in biologically effective UV dose in October, 1988 compared to March, 1989 is clearly evident. The main cause of this asymmetry appears to be the coincident deficiency in ozone abundance appears to be the coincident deficiency in ozone abundance by about 8% in spring compared to fall. The percent increase in UV dose per percent decrease in ozone abundance is about 2.5 in agreement with theoretical predictions. The total ozone amount is generally depleted (to about 250 DU) during October 1988, but there are large day-to-day fluctuations. Presumably these fluctuations are caused primarily by the motion of the polar vortex. After summer solstice UV radiation levels and ozone amounts exhibit much less pronounced day-to-day fluctuations. No spring/fall asymmetry in cloudiness, as it affects the surface ultraviolet radiation budget, is discernible from the measurements if the surface albedo is assumed to vary symmetrically around solstice.

Stamnes, K.; Slusser, J.; Bowen, M. (Univ. of Alaska, Fairbanks (USA)); Booth, C.; Lucas, T.

1990-11-01

73

Visible and near-ultraviolet spectroscopy at McMurdo Station, Antarctica. 7. OClO diurnal photochemistry and implications for ozone destruction  

SciTech Connect

Observations of the ratio between the change in slant column abundance of OClO and that of ozone as a function of solar zenith are used to deduce the diurnal cycle of the daytime OClO column abundance above Antarctica during September 1987. This approach effectively normalizes other factors such as air mass factor changes and allows study of the photochemical variations of OClO during twilight. The data exhibits a marked increase in OClO at large solar zenith angles in the evening twilight (near 90{degree}-93{degree}), in agreement with model predictions. The increase is likely caused primarily by the attenuation of the OClO photolysis rate in the twilight. Knowledge of both the full diurnal and daily variations of OClO deduced from the data can be used to evaluate the destruction of the ozone column due to coupled chlorine-bromine chemistry. The inferred ozone loss above McMurdo Station assuming presently accepted photochemistry is 19.5 {plus minus} 10 Dobson units over the entire month of September, or about 20 {plus minus} 10% of the observed total column decline. This value is in general agreement with inferences drawn from in-situ measurements of ClO and BrO. In mid-September, available OClO and HOCl column measurement suggest that the chlorine-bromine and chlorine-hydrogen cycles respectively contribute about 22-28% and 3-4% of the observed rate of column ozone decrease at that time of the month. Model calculations constrained by ClO, BrO, and OClO measurements suggest that these mechanisms combined with photolysis of the ClO dimer can account for much, and possibly all, of the total ozone destruction rate observed in mid-September 1987.

Solomon, S.; Sanders, R.W. (NOAA, Boulder, CO (USA)); Miller, H.L. Jr. (Univ. of Colorado, Boulder (USA))

1990-08-20

74

High-resolution dimethyl sulfide and dimethylsulfoniopropionate time series profiles in decaying summer first-year sea ice at Ice Station Polarstern, western Weddell Sea, Antarctica  

NASA Astrophysics Data System (ADS)

High-resolution profiles of ice dimethyl sulfide (DMS) and dimethylsulfoniopropionate (DMSP) concentrations were measured together with a suite of ancillary physical and biological properties during a time series of decaying summer-level first-year sea ice throughout December 2004 during the Ice Station Polarstern drift experiment (western Weddell Sea, Antarctica). Ice DMSP and DMS concentrations were always maximum at the bottom of the ice sheet (636-2627 and 292-1430 nM, respectively) where the highest chlorophyll a levels were also found (15-30 ?g L-1). Throughout the observation period, the autotrophic surface community (32-205 ?g C L-1) was dominated by Phaeocystis sp. while the bottom community (1622-3830 ?g C L-1) mainly consisted of pennate diatoms. This illustrates that, although being known for lower DMSP-to-chlorophyll a ratios than Phaeocystis sp., diatoms dominated the overall DMSP production because of their much larger biomass. Decreasing DMSP concentrations and increasing DMS-to-DMSP ratios in the bottom layers with time suggested active DMSP-to-DMS conversion in a slowly degrading environment. Drastic temporal brine volume and brine salinity changes associated with the decaying sea ice cover are shown to directly impact (1) the migration of DMSP and DMS through the brine network, (2) the DMSP-to-DMS conversion processes within the ice interior, and (3) the physiological response of the ice algae. First-order flux estimates show that decaying summer-level first-year sea ice alone can significantly contribute to the regional sulfur budget of the Weddell Sea with an estimated average loss rate of 5.7 ?mol DMS(P) m-2 d-1) toward the atmosphere and the ocean.

Tison, J.-L.; Brabant, F.; Dumont, I.; Stefels, J.

2010-12-01

75

Observed trends for CF3-containing compounds in background air at Cape Meares, Oregon, Point Barrow, Alaska, and Palmer Station, Antarctica.  

PubMed

The concentrations of CF(3)-containing compounds in archived air samples collected at Cape Meares, Oregon, from 1978 to 1997, at Point Barrow, Alaska, from 1995 to 1998, and at Palmer Station, Antarctica, from 1991 to 1997, were determined by high resolution gas chromatography and high resolution mass spectrometry. The CF(3)-containing compounds measured by this method and discussed here are: the perfluorinated compound, C(3)F(8) (FC 218); four perhalogenated compounds, CF(3)Cl (CFC 13), CF(3)CF(2)Cl (CFC 115), CF(3)CFCl(2) (CFC 114a), and CF(3)Br (Halon 1301); and three hydrofluorocompounds, CF(3)H (HFC 23), CF(3)CH(3) (HFC 143a), and CF(3)CH(2)F (HFC 134a). For four of these compounds, very few measurements have been previously reported. The atmospheric concentrations of all of the CF(3)-containing compounds continuously increased in time over the sample collection periods. From these data, the annual rates of emission into the atmosphere have been estimated. The emission rates fall into one of three distinct categories. The annual emission rates of C(3)F(8), CF(3)H, CF(3)CH(3), and CF(3)CH(2)F have continuously increased over the last two decades. That of CF(3)CFCl(2) has decreased continuously. Emission rates for CF(3)Cl, CF(3)CF(2)Cl, and CF(3)Br reached maximum levels in the late 1980s, and have been decreasing in the 1990s. The emission rates of C(3)F(8), CF(3)CH(3) and CF(3)CH(2)F were nearly zero 20 years ago but have increased rapidly during the last decade. PMID:15050808

Culbertson, J A; Prins, J M; Grimsrud, E P; Rasmussen, R A; Khalil, M A K; Shearer, M J

2004-05-01

76

Five-year analysis of background carbon dioxide and ozone variations during summer seasons at the Mario Zucchelli station (Antarctica)  

NASA Astrophysics Data System (ADS)

The work focuses on the analysis of CO2 and O3 surface variations observed during five summer experimental campaigns carried out at the ‘Icaro Camp’ clean air facility (74.7°S, 164.1°E, 41 m a.s.l.) of the ‘Mario Zucchelli’ Italian coastal research station. This experimental activity allowed the definition of summer average background O3 values that ranged from 18.3 ± 4.7 ppbv (summer 2005-2006) to 21.3 ± 4.0 ppbv (summer 2003-2004). Background CO2 concentrations showed an average growth rate of 2.10 ppmv yr-1, with the highest CO2 increase between the summer campaigns 2002-2003 and 2001-2002 (+2.85 ppmv yr-1), probably reflecting the influence of the 2002/2003 ENSO event. A comparison with other Antarctic coastal sites suggested that the summer background CO2 and O3 at MZS-IC are well representative of the average conditions of the Ross Sea coastal regions. As shown by the analysis of local wind direction and by 3-D back-trajectory calculations, the highest CO2 and O3 values were recorded in correspondence to air masses flowing from the interior of the Antarctic continent. These results suggest that air mass transport from the interior of the continent exerts an important influence on air mass composition in Antarctic coastal areas.

Cristofanelli, P.; Calzolari, F.; Bonafè, U.; Lanconelli, C.; Lupi, A.; Busetto, M.; Vitale, V.; Colombo, T.; Bonasoni, P.

2011-11-01

77

Chemical composition of size-segregated aerosol collected all year-round at Concordia Station (Dome C, Antarctica). Transport processes and climatic implications.  

NASA Astrophysics Data System (ADS)

Ice-core stratigraphies of chemical components of atmospheric gases and aerosols trapped in the snow layers by scavenging processes are a powerful tool in understanding past climatic and environmental changes. The deep ice core drilled at Dome C in the framework of the EPICA project allowed reconstructing the last 8 glacial-interglacial cycles and highlightened the complex relationships between climatic forcings and environmental feedback processes. In interpreting ice core records as a function of past climatic variations, some difficulties arise from uncertainties in considering selected chemical species as reliable markers of climatic and environmental processes and in attributing the different load and composition of aerosols over Antarctica to changes in source intensity (such as aridity, wind strength, emersion of continental platform by sea-level lowering etc..) and/or to variations in atmospheric processes (such as meridional and zonal atmospheric circulation, polar vortex intensity, scavenging efficiency, transport pathways etc..). Besides, two new aspects are actually under discussions: the possible use of Na as sea-ice cover marker (via frost flower formation on the sea-ice surface during the pack-ice formation) and the identification of continental source areas for mineral dust reaching internal regions of Antarctica during glacial and interglacial periods. In order to better address such controversial issues, since 2005 a continuous, high temporal resolution size-segregated aerosol and surface snow sampling has been performed at Dome C (central East Antarctic Plateau, 75° 06' S, 123° 23' E), in the framework of "Station Concordia" Project (a Italian PNRA- French IPEV joint program). The chemical analysis of size-segregated aerosol and daily superficial snow samples, collected all year-round for more than 4 years, can contribute to clarify some of the above mentioned topics. In particular: the possible seasonal pattern of sea spray aerosol could be related to sea-ice formation timing and/or to changes in zonal wind intensity and atmospheric pathway; the mineralogical analysis of insoluble dust particles can allow the identification of continental sources, by comparison with soils collected in the potential source areas (PSAs); finally, the seasonal pattern of biogenic markers (such as methanesulphonic acid and non-sea-salt sulphate) can be linked to sea surface temperature, sea-ice cover and southern-hemisphere circulation modes (e.g., SOI, AAO or SAM and ACW). As regard as depositional and post-depositional processes, the analysis of chemical markers in aerosol, superficial snow and hoar crystals, sampled contemporaneously, will allow understanding the key factors (e.g., snow acidity, solar irradiation) affecting the preservation of components reversibly fixed in the snow layers (such as, for instance, methanesulphonic acid, nitrate and chloride). A summary of the major results from the chemical analysis of aerosol and snow collected at Dome C is here presented.

Udisti, Roberto; Becagli, Silvia; Frosini, Daniele; Galli, Gaia; Ghedini, Costanza; Rugi, Francesco; Severi, Mirko; Traversi, Rita

2010-05-01

78

GIS-based application of resource selection functions to the prediction of snow petrel distribution and abundance in East Antarctica: Comparing models at multiple scales  

Microsoft Academic Search

Snow petrel numbers must be of the order of several millions. However, accurate population estimates are sparse although such information is necessary to monitor potential changes in the Antarctic ecosystem. A census of snow petrel nests was conducted at Casey (East Antarctica) during summer 2002–2003. Twenty percent of the ice-free areas (available nesting habitat for snow petrels) was surveyed using

Frédérique Olivier; Simon J. Wotherspoon

2005-01-01

79

Distribution and abundance of Wilson’s storm petrels Oceanites oceanicus at two locations in East Antarctica: testing habitat selection models  

Microsoft Academic Search

Over the last decades, Antarctic seabird populations have been studied as bioindicators of the variability in the Southern Ocean marine ecosystem. Little information is available on the distribution and abundance of Wilson’s storm petrel (Oceanites oceanicus) in East Antarctica although the bioindicator value of this species has been investigated. Regional surveys were conducted at two coastal locations, Casey (66°S, 110°E)

Frédérique Olivier; Simon J. Wotherspoon

2006-01-01

80

Long-period tides observed with a superconducting gravimeter at Syowa Station, Antarctica, and their implication to global ocean tide modeling  

NASA Astrophysics Data System (ADS)

The long-period tides (Mf and Mm waves) were analyzed with the 2 years data obtained with a superconducting gravimeter (SG) installed at Syowa Station (69.0° S, 39.6° E), Antarctica. The observed amplitudes, phase lags and amplitude factors (? factors) were 11.642 +/- 0.035 ?Gal, -0.12° +/- 0.17° and 1.1218 +/- 0.0034 for the Mf wave, and 6.143 +/- 0.058 ?Gal, 0.33° +/- 0.54° and 1.1205 +/- 0.0106 for the Mm wave, respectively (1 ?Gal = 10-8 m s-2). The ocean tide effects (effects of the attraction and loading due to the ocean mass) at the observation site were estimated using the five global ocean tide models: equilibrium ocean tide model, Schwiderski model, Dickman model, CSR model, and Desai and Wahr model. The averages of the five estimates are 0.433 ?Gal and 0.244 ?Gal in amplitude and 192.9° and 179.5° in phase for the Mf and Mm waves, respectively. The five estimates differ by a maximum of 0.104 ?Gal in amplitude and 18.8° in phase for the Mf wave, and by 0.033 ?Gal and 6.4° for the Mm wave. The estimated Mm phases are nearly 180° for the five models, and the variation of their values among the models is relatively small compared with that of the Mf phases. These indicate that the Mm wave is much closer to an equilibrium tide than the Mf wave. Due to the variation of the ocean tide corrections, the corrected ? factors were scattered within the ranges of 1.158 to 1.169 for the Mf wave and 1.163 to 1.169 for the Mm wave. However, it is noted that the mean ? factors of the five ocean models, i.e. 1.162 +/- 0.023 for the Mf wave and 1.165 +/- 0.014 for the Mm wave, prefer slightly larger value rather than those estimated from the theory of the elastic tide.

Sato, Tadahiro; Ooe, Masatsugu; Nawa, Kazunari; Shibuya, Kazuo; Tamura, Yoshiaki; Kaminuma, Katsutada

1997-10-01

81

A dramaturgical analysis of social order in the Supreme Court Casey decision  

Microsoft Academic Search

When the Supreme Court handed down its decision in Casey v Planned Parenthood of Pennsylvania, the abortion debate was effectively ended. While the Casey decision upheld the central holding of Roe v Wade , the Court legitimized extensive restrictions on abortion. Consequently, the Court appeased both sides of the volatile abortion debate. Seemingly, the pro-life side and pro-choice side were

Margaret Ann McGee

2000-01-01

82

Astronomy in Antarctica in 2009  

NASA Astrophysics Data System (ADS)

This article summarises the subject matter of Special Session 3 at IAU General Assembly XXVII in Rio de Janeiro, Brazil, which took place on August 6-7, 2009. In it, we overview the state of Astronomy in Antarctica as it is in 2009. Significant astronomical activity is now taking place at four stations on the Antarctic plateau (South Pole, Domes A, C & F), as well as at the coastal station of McMurdo.

Burton, Michael G.

2010-11-01

83

Classroom Antarctica  

NSDL National Science Digital Library

This website is a collection of units designed to teach students about the global importance of Antarctica. Topics covered in these units includes ice, the ocean, geology, weather, topography, auroras, the history of Antarctic exploration, living in Antarctica, animals, plants, the Antarctic Treaty, and the environment. Each unit has a selection of activities that are adaptable to the range of abilities in a class and the particular interests of the students. There are hundreds of useful web links throughout and a wealth of support material listed under Classroom Resources.

Haywood, Elizabeth

84

Astronomy in Antarctica  

NASA Astrophysics Data System (ADS)

Antarctica provides a unique environment for astronomers to practice their trade. The cold, dry and stable air found above the high Antarctic plateau, as well as the pure ice below, offers new opportunities for the conduct of observational astronomy across both the photon and the particle spectrum. The summits of the Antarctic plateau provide the best seeing conditions, the darkest skies and the most transparent atmosphere of any earth-based observing site. Astronomical activities are now underway at four plateau sites: the Amundsen-Scott South Pole Station, Concordia Station at Dome C, Kunlun Station at Dome A and Fuji Station at Dome F, in addition to long duration ballooning from the coastal station of McMurdo, at stations run by the USA, France/Italy, China, Japan and the USA, respectively. The astronomy conducted from Antarctica includes optical, infrared, terahertz and sub-millimetre astronomy, measurements of cosmic microwave background anisotropies, solar astronomy, as well as high energy astrophysics involving the measurement of cosmic rays, gamma rays and neutrinos. Antarctica is also the richest source of meteorites on our planet. An extensive range of site testing measurements have been made over the high plateau sites. In this article, we summarise the facets of Antarctica that are driving developments in astronomy there, and review the results of the site testing experiments undertaken to quantify those characteristics of the Antarctic plateau relevant for astronomical observation. We also outline the historical development of the astronomy on the continent, and then review the principal scientific results to have emerged over the past three decades of activity in the discipline. These range from determination of the dominant frequencies of the 5 min solar oscillation in 1979 to the highest angular scale measurements yet made of the power spectrum of the CMBR anisotropies in 2010. They span through infrared views of the galactic ecology in star formation complexes in 1999, the first clear demonstration that the Universe was flat in 2000, the first detection of polarization in the CMBR in 2002, the mapping of the warm molecular gas across the ~ 300 pc extent of the Central Molecular Zone of our Galaxy in 2003, the measurement of cosmic neutrinos in 2005, and imaging of the thermal Sunyaev Zel’dovich effect in galaxy clusters in 2008. This review also discusses how science is conducted in Antarctica, and in particular the difficulties, as well as the advantages, faced by astronomers seeking to bring their experiments there. It also reviews some of the political issues that will be encountered, both at national and international level. Finally, the review discusses where Antarctic astronomy may be heading in the coming decade, in particular plans for infrared and terahertz astronomy, including the new facilities being considered for these wavebands at the high plateau stations.

Burton, Michael G.

2010-10-01

85

Discover Antarctica  

NSDL National Science Digital Library

Antarctica is arguably the continent that most people know the least about, so it is nice to find out that the Royal Geographical Society (in partnership with the British Antarctic Survey) has created this website which explores all aspects of life on this landmass. The "Imagining Antarctica" area is a fine place to start, and visitors can watch a short video clip about the continent, test their existing knowledge with a short quiz, and then participate in a "being there" activity. Other engaging sections include "A Changing Climate", "Living There Today" and "What Future?" The site also lists all of the resources by format, including audio files, video clips, Word documents, and images. Finally, the site also includes a "Teachers' Area", which offers a number of learning activities for students and teacher notes that are correlated to each of the main sections of the site.

86

Lidar measurement of the stratospheric aerosol layer at Syowa Station (69.00 deg S, 39.35 deg E), Antarctica  

NASA Astrophysics Data System (ADS)

Polar stratospheric aerosols (PSA) were measured over Antarctica in 1983 using ground-based lidar. A decrease in stratospheric temperature was correlated with a rise in extinction in the stratosphere. The temperature decrease was associated with an increase in stratospheric particulate matter, which may not have been the growth of ice crystals. The growth observed was commensurate with previous reports of the formation of polar stratospheric clouds. Good characterization of the PSA is asserted to depend on the acquisition of data on the H2O vapor, H2SO4 content, chemical composition and aerosol particle sizes in the PSA.

Iwasaka, Y.

1985-04-01

87

Promoting Fetal Personhood: The Rhetorical and Legislative Strategies of the Pro-Life Movement after Planned Parenthood v. Casey  

Microsoft Academic Search

:The article examines the pro-life movement's efforts to advance the legal, moral, and political arguments for fetal personhood in the period following the Supreme Court's case Planned Parenthood v. Casey. It begins with an overview of the efforts to define the fetus as a legal person prior to Casey, and proceeds to describe the opportunity created for pro-life forces by

Glen A. Halva-Neubauer; Sara L. Zeigler

2010-01-01

88

Seasonal temperature variation around the mesopause inferred from a VHF meteor radar at King Sejong Station (62S, 59W), Antarctica  

Microsoft Academic Search

A VHF meteor radar, installed at King Sejong Station in March, 2007, has been detecting echoes from more than 20,000 meteors per day. Meteor echoes are decayed typically within seconds as meteors spread away by atmospheric diffusion. The diffusion coefficients can thus be obtained from decay times of meteor echo signals, providing with information on the atmospheric temperatures and pressures

Yongha Kim; Jeong-Han Kim; Changsup Lee; Gun-Hwa Jee

2008-01-01

89

Decrease of auroral intensity associated with reversal of plasma convection in response to an interplanetary shock as observed over Zhongshan station in Antarctica  

NASA Astrophysics Data System (ADS)

We examined temporal variations of a dayside aurora and corresponding ionospheric plasma convection observed by an all-sky camera (ASC) and the Super Dual Auroral Radar Network (SuperDARN) over Zhongshan (ZHS), located at -74.5° in magnetic latitude (MLAT) in Antarctica, during a geomagnetic sudden commencement (SC) event that occurred on 27 May 2001. Simultaneous ASC observations at South Pole (SP, -74.3° MLAT) were also analyzed. During the SC time, ZHS and SP were located in the postnoon (1610 MLT) and prenoon (1100 MLT) sectors, respectively. Before the SC onset (1458UT), the ASC at ZHS observed an auroral arc with moderate intensity in the poleward direction of the field of view (FOV), and the SuperDARN radar detected sunward ionospheric plasma flow over ZHS. Just after the SC onset, the auroral intensity over ZHS decreased rapidly and the direction of the plasma flow was reversed to antisunward. Decrease of auroral intensity and reversal of the associated plasma convection in response to a sudden increase of the solar wind dynamic pressure at the early stage of a SC event has never been reported before. We suggest that these observational results were generated by a downward field-aligned current (FAC) and are consistent with a physical model of SC. The model predicts the appearance of a pair of FACs flowing downward (upward) in the postnoon (prenoon) sector at the very beginning of the SC, which is also supported by our observations. Consistence of the detailed observations with the model will be discussed in the paper, and we argue that here we present the first optical observational evidence supporting the validity of the model.

Liu, J. J.; Hu, H. Q.; Han, D. S.; Araki, T.; Hu, Z. J.; Zhang, Q. H.; Yang, H. G.; Sato, N.; Yukimatu, A. S.; Ebihara, Y.

2011-03-01

90

Astrophysics from Antarctica (IAU S288)  

NASA Astrophysics Data System (ADS)

Editorial; 1. Review of Antarctic astronomy; 2. Astrophysics from Antarctica; 3. Understanding the Antarctic environment; 4. Cosmic microwave background radiation; 5. Neutrinos; 6. Cosmogenic signatures from ice and atmosphere; 7. Sub-millimetre and terahertz astronomy; 8. Optical and infrared astronomy; 9. Antarctic stations and their observatories; 10. The Arctic analogue; 11. Facilities for the future; Summary; Index.

Burton, Michael G.; Cui, Xiangqun; Tothill, Nicholas F. H.

2013-02-01

91

Measuring Foster Parent Potential: Casey Foster Applicant Inventory-Worker Version (CFAI-W)  

ERIC Educational Resources Information Center

Objective: This article examines the psychometric properties of the Casey Foster Applicant Inventory-Worker Version (CFAI-W), a questionnaire designed to assess the potential of foster family care applicants to provide foster care. Method: Retrospective data were collected from 208 foster care workers who completed two copies of the CFAI-W, one…

Cuddeback, Gary S.; Buehler, Cheryl; Orme, John G.; Le Prohn, Nicole S.

2007-01-01

92

Measuring Foster Parent Potential: Casey Foster Parent Inventory-Applicant Version  

ERIC Educational Resources Information Center

Objective: The Casey Foster Applicant Inventory-Applicant Version (CFAI-A) is a new standardized self-report measure designed to assess the potential to foster parent successfully. The CFAI-A is described, and results concerning its psychometric properties are presented. Method: Data from a sample of 304 foster mothers from 35 states are analyzed.…

Orme, John G.; Cuddeback, Gary S.; Buehler, Cheryl; Cox, Mary Ellen; Le Prohn, Nicole S.

2007-01-01

93

A Relational Approach to Moral Decision-Making: The Majority Opinion in "Planned Parenthood v. Casey."  

ERIC Educational Resources Information Center

Defines a relational approach to moral reasoning. Notes that the Supreme Court, in "Planned Parenthood v. Casey," rejected simplistic approaches to moral reasoning and acknowledged the complex web of relationships involved in abortion decision making. Suggests that rhetoricians "revision" the art of persuasion to place more emphasis on relational…

Sullivan, Patricia A.; Goldzwig, Steven R.

1995-01-01

94

A Relational Approach to Moral Decision-Making: The Majority Opinion in "Planned Parenthood v. Casey."  

ERIC Educational Resources Information Center

|Defines a relational approach to moral reasoning. Notes that the Supreme Court, in "Planned Parenthood v. Casey," rejected simplistic approaches to moral reasoning and acknowledged the complex web of relationships involved in abortion decision making. Suggests that rhetoricians "revision" the art of persuasion to place more emphasis on relational…

Sullivan, Patricia A.; Goldzwig, Steven R.

1995-01-01

95

X Marks the Spot While Casey Strikes Out: Two Controversial Abortion Decisions  

Microsoft Academic Search

This article studies and defines abortion law in Ireland after X and in the United States after Casey. It addresses how these decisions affect Irish and American women's rights, respectively, to secure an abortion. It also scrutinizes the justices' opinions and criticizes the reasoning for their holdings. This article argues that both Courts changed their nations' straightforward abortion laws to

Sabina Zenkich

2010-01-01

96

A relational approach to moral decision?making: The majority opinion in planned parenthood V. Casey  

Microsoft Academic Search

Advocates supporting and opposing abortion rights were disappointed by the United Stales Supreme Court ruling on the Pennsylvania Abortion Control Act in Planned Parenthood v. Casey (1992). The majority opinion upheld a “fundamental” right to abortion prior to fetal viability but also affirmed a State's right to regulate, abortions. Thus, in establishing a middle ground, the Court rejected simplistic approaches

Patricia A. Sullivan; Steven R. Goldzwig

1995-01-01

97

How Planned Parenthood v. Casey (Pretty Much) Settled the Abortion Wars  

Microsoft Academic Search

More than twenty-one years after Robert Bork's failed Supreme Court nomination and seventeen years after Planned Parenthood of Southeastern Pennsylvania v. Casey, the rhetoric of abortion politics remains unchanged. Pro-choice interests, for example, argue that states are poised to outlaw abortion and that Roe v. Wade is vulnerable to overruling. In this Essay, I will debunk those claims. First, I

Neal Devins

2009-01-01

98

Winter Count: Taking Stock of Abortion Rights After Casey and Carhart  

Microsoft Academic Search

This article outlines the current landscape of the constitutional right to abortion established in Roe v. Wade. Analyzing the court's holdings in Planned Parenthood v. Casey and Stenberg v. Carhart, the author details the ways in which recognition of a government interest in potential life at any stage in a pregnancy, as well as the lofty \\

Caitlin E. Borgmann

2004-01-01

99

Improvement of ocean loading correction for superconducting gravimeter data of GGP including Syowa Station, Antarctica, and the effect on fluid core resonance (FCR) parameters  

NASA Astrophysics Data System (ADS)

The free core nutation (FCN), also refered to as the nearly diurnal free wobble, is due to the pressure coupling between the liquid core and the solid mantle. The FCN enhances the resonance with the diurnal earth tide. Investigation of resonance parameters of FCR (eigenperiod, quality factor Q, and resonance strength) is essential for the Earth's deep interior dynamics and structure. The eigenperiod directly depends on the core-mantle boundary (CMB) ellipticity and on the mantle's inelasticity. The quality factor Q is a direct consequence of damping mechanisms inside the Earth (Sasao et al., 1980; Sasao and Wahr, 1981; Florsch and Hinderer, 2000). For determining theseresonance parameters, the tidal gravimetric factor based on superconducting gravimeter (SG) data is used. We used the gravity data of 4 stations, from 1992 through 2002 at Syowa Station, from 1997 through 2007 at Strasbourg, from 1998 through 2007 at Metsahovi, from 2000 through 2006 at Sutherland, of the GGP Data Center. The tidal gravity parameters were determined using the BAYTAP-G software package (Ishiguro et al., 1981; Tamura et al., 1991). In this study, we focused on the influence of ocean loading effect on precise estimation of FCN parameters. The global ocean tidal models, CSR4.0 (Eanes and Bettadpur, 1999), GOT99.2b (Ray, 1999), FES2004 (Lyard et al., 2006) and TPXO7.1 (Egbert and Erofeeva, 2002) models are tested. These models are accomodated to the GOTIC2 for ocean loading estimation program (Matsumoto et al. 2001). The quality factor Q is dependent on the phase delay of the tidal waves, that means the imaginary part of gravimetric factor corrected for ocean loading effect is an important point for this inverse problem(Florsch and Hinderer, 2000). We present how much the accuracy of FCR parameters can be improved by adopting proper ocean models to each station (Le provost et al., 2001). For this work, we have applied minor waves for ocean loading correction (Matsumoto, 2003), and the ocean loading effect from other kinds of Green's functions based on an elastic Earth model (Francis and Dehant, 1987) and an inelastic Earth model (Okubo and Tsuji, 2001) was estimated. We show the dependency on these effect on accurate estimation of resonance parameters. Because the gravity data from Syowa Station has much ocean loading effect, i.e. as a noise, the reduction of this effect is very important. We show how much the recent global ocean models (FES2004 and TPXO.7.1) can decrease the residual gravity and improve the accuracy of the FCR parameters. Finally, we test the effect of the random error in the ocean loading calculation on the determination of the resonance parameters in the inverse problem. For this work, white noise s were added to the observed gravimetric delta factors when solving the non-linear least squares problems to see the stability of the solved resonance parameters.

Kim, Taehee; Shibuya, Kazuo; Doi, Koichiro; Aoyama, Yuichi; Hayakawa, Hideaki

2010-05-01

100

Geodetic estimates of the vertical crustal velocity field in Antarctica  

NASA Astrophysics Data System (ADS)

We present the initial results of the West Antarctic GPS Network (WAGN), which was initiated in the 2002/03 Antarctic field season. Specifically we present vertical velocity estimates for all WAGN stations with a total occupational time span of 3 years or more. Most of these station have been observed for at least four years, and many for 5 years or more. We present solutions at 12 stations in West Antarctica, as well as for 4 stations in the upper Antarctic Peninsula, and 7 CGPS stations in East Antarctica. We realized our reference frame by minimizing the vertical velocities of 202 CGPS stations located outside of the Antarctic continent, and by minimizing the horizontal velocities of 11 stations within Antarctica. The vertical velocities of the East Antarctic stations are all small, in agreement with most models for GIA. The observed pattern of vertical motion within West Antarctica and the Peninsula does not correspond well with any GIA model known to us. We shall discuss the implications for ice mass balance studies based on GRACE observations.

Bevis, M.; Smalley, R.; Kendrick, E.; Dalziel, I.; Caccamise, D.; Taylor, F.; Willis, M.; Zhou, H.; Brown, A.; Konfal, S.; Wilson, T.; Raleigh, D.; Nylen, T.

2008-12-01

101

Antarctica Research in the Polar Research Center of China  

NASA Astrophysics Data System (ADS)

The Polar Research Center of China (PRCC) was established in the early 1990s (formerly Polar Research Institute of China) to serve as the leading national organization for Antarctica-related research in China. Current research areas of center staff scientists include glaciology and paleoclimatology, upper atmospheric physics, polar and marine biology, and oceanagrphy. In addition to its own active research, PRCC on behalf of the China Antarctic and Arctic Administration coordinates and provides logistical support to Antarctica research activities by all Chinese scientists. The center organizes and manages the annual Chinese Research Expedition to Antarctica with participation from many other national and academic institutions. In its first decade of existence, PRCC has accumulated valuable experience in conducting and facilitating research in Antarctica, particularly in the areas of logistic support for field programs, staffing and managing the two permanent stations in Antarctica (Great Wall and Zhongshan). The successful operation of the Chinese Antarctica research program has benefitted from generous assistance from several more established national (for example, Australia, Japan and the United States) Antarctica programs and from frequent contact with international colleagues working on Antarctica research. Among the many issues and problems frequently encountered in the last decade are: (1) The scale of research activities is often seriously constrained by logistic capabilities and funding; (2) Limited computer network and library resources hamper speedy and timely access to relevant international scientific literature; (3) Acquisition of high quality scientific (field and laboratory) equipment and special supplies can be limited by funding and access to suppliers.

Zhang, Z.; Li, Y.; Liu, S.; Cole-Dai, J.

2003-12-01

102

Bringing Antarctica Home  

ERIC Educational Resources Information Center

|When one thinks of the amazing creatures of Antarctica, an insect probably does not come to mind. But this unlikely animal, and a scientific expedition to Antarctica, was the foundation for a learning event that created a community of learners spanning kindergarten through sixth grade and extended beyond the classroom. Miami University's…

Constible, Juanita; Williams, Lauren; Faure, Jaime; Lee, Richard E., Jr.

2012-01-01

103

Antarctica Part One  

NSDL National Science Digital Library

In this video, Jonathan treks all the way to Antarctica to investigate life south of the polar circle. Along the way he dives in the majestic kelp forests of Patagonia, where crabs rule the sea floor. Once he arrives in Antarctica, his adventures continue. He swims with penguins, dives under an iceberg, meets a massive jellyfish 3 feet wide, and has an incredible encounter with a Leopard seal, the apex predator of Antarctica. Part 1 finds Jonathan diving in Ushuaia, Patagonia in Argentina before boarding the ship to Antarctica, then he finally gets to Antarctica and meets some penguins! This program won a New England Emmy Award! Please see the accompanying lesson plan for educational objectives, discussion points and classroom activities.

Productions, Jonathan B.

2011-05-04

104

Abortion on the Supreme Court agenda: Planned Parenthood v. Casey and its possible consequences.  

PubMed

On June 29, 1992, the US Supreme Court released its Planned Parenthood of Southeastern Pennsylvania v. Casey opinion. A majority of the Court reaffirmed the essential holding of the landmark Roe v. Wade case, including a recognition of a woman's guaranteed constitutional right to choose an abortion before viability. At the same time, the Court eliminated Roe's trimester framework, established a new, less stringent undue burden standard for reviewing governmental limitations upon woman's right to choose, and applied this standard in upholding the constitutionality of most of Pennsylvania's abortion restrictions. Currently, 15 states have informed consent laws, and 13 states have laws requiring waiting periods between counseling and the abortion; many states also require parental notification or consent, some with the option of judicial bypass. Now that the Court has upheld the constitutionality of restrictions such as these, it is expected that states will enforce existing provisions and impose new limitations as well. In Illinois, the proposed Abortion Informed Consent Act would require the dissemination of particular information and then impose a 72-hour waiting period between counseling and abortion. In North Dakota, a state with only 1 abortion clinic, the State Attorney General announced that he expected to begin enforcing a 24-hour waiting period. And in Tennessee, as in other states, Casey may encourage courts to lift injunctions that have prevented enforcement of waiting periods or other restrictions. Casey explicitly implicates patient autonomy, the doctor patient relationship, and the First Amendment rights of health professionals. As the Court's new interpretation of Roe suggests, the right to privacy will never be immune from redefinition. PMID:1434769

Koslov, T I

1992-01-01

105

Antarctica - Laboratory For Science.  

National Technical Information Service (NTIS)

Shows recent research into terrestrial and marine ecosystems, weather and climate, surface and subsurface geology, and changes in the size of the ice sheet. The continent of Antarctica and its surrounding oceans have been the subjects of continuous scient...

1994-01-01

106

Beyond Roe, after Casey: the present and future of a "fundamental" right.  

PubMed

Although the US Supreme Court recently reaffirmed a woman's right to end a pregnancy before viability, many women remain unable to exercise that right because their access to abortion is limited. 83% of the counties in the nation have no abortion providers, and many women must travel hundreds of miles to obtain an abortion. In its Planned Parenthood of Southeastern Pennsylvania vs. Casey decision, the Supreme Court upheld what it felt were the central tenets of Roe vs. Wade but appointed an "undue burden" standard instead of a "strict scrutiny" standard for the courts to use when determining whether or not a state restriction is to be allowed. This means that women must prove "undue" harm from a restriction. 2 other new concepts contained in Casey are that the state has an interest in fetal life throughout a pregnancy and that the government does not have to remain neutral in an abortion case even if it did not involve the issue of funding. This means that states can try to discourage a woman's choice to have an abortion. Since Casey, the Supreme Court has refused to review several abortion cases and federal courts have taken action allowing abortion restrictions to go into effect in Pennsylvania, Utah, South Dakota, North Dakota, and Mississippi. State courts in Ohio, Oklahoma, Tennessee, Alaska, New York, and West Virginia have also heard abortion restriction cases in the past year. These restrictions involved a waiting period, criminalization, a residency requirement, a community hospital's ban on abortions, and state funding for abortion. Following the Casey decision, efforts were made to codify Roe by reintroducing the Freedom of Choice Act in Congress. During the committee process, however, the bill was amended in such a way as to make pro-choice advocates doubt that the amended version will be able to accomplish the aims of the original Act. Because the High Court ruled in Bray vs. Alexandria Women's Health Clinic that the ability of abortion clinics to prevent antichoice blockades is limited since the blockades do not violate civil rights laws, Congress is advancing a measure called "The Freedom of Access to Clinic Entrances Act" to counteract the harassment which occurs outside of the clinics. State legislatures have taken action to impose mandatory delays and biased counseling on abortion-seekers, restrict the access of young women to abortion, prohibit Medicaid funding for abortion, require unnecessary reporting regulations on the part of abortion services, and institute protective measures for reproductive rights. Although the right acknowledged in the Roe vs. Wade decision continues to exist, the struggle for women's reproductive autonomy must go forward to assure constitutional protection for the right to choose and guaranteed access to that right for all women. PMID:8274872

Benshoof, J

1993-01-01

107

Live from Antarctica: The coldest, windiest place on Earth  

NASA Astrophysics Data System (ADS)

In this first part of a four part 'Passport to Knowledge Special', hosted by Camille Jennings from Maryland Public Television, children from Maryland and Texas schools had the opportunity to directly interact with and ask questions of scientists and researchers in Antarctica live. The physical characteristics of Antarctica are featured, along with their effects on the human and microbiological organisms living in the region. The reasons behind the clothing worn in the Antarctic and the importance of the meteorological station are featured. Interviews with Professor Ian Dolziel (U of Texas) and Lt. commander John Joseph, NSFA (the head of the Navy Meteorology Center) occur with the school children, along with actual video footage of the surrounding geological features and geography. The 'Weatherops' is located at McMurdo Station, Antarctica.

108

Properties, formation, and geo-ecological significance of organic soils in the coastal region of East Antarctica (Wilkes Land)  

Microsoft Academic Search

The ice-free antarctic vegetation oases are characterized by specific soil patterns. Four organic soils from mosses in Wilkes Land close to the Australian Casey Station (latitude: 66°18?S, longitude: 110°32?E) are discussed with respect to soil formation, ecology, and distribution. A soil survey of the ice-free coastal landscape suggests that mosses are the main source of organic soils. The soil organic

Lothar Beyer

2000-01-01

109

Federal court holds first live evidentiary hearing on mandatory delay since Casey.  

PubMed

Four days beginning on June 20, U.S. District Court Judge Nancy Edmunds heard testimony and argument in Northland Family Planning, Inc. vs. Engler, a challenge to Michigan's 1993 mandatory 24-hour delay and biased counseling law. Scheduled to take effect on April 1, the statute was temporarily blocked by Judge Edmunds on March 18--eight days after two dozen women's health care providers and advocates filed suite (see RFN III/5). The hearing this week on plaintiff's request for a preliminary injunction marked the first time since the U.S. Supreme Court's 1992 decision in Planned Parenthood vs. Casey that Witnesses have appeared in federal court to testify about the likely impact of such a measure. In the wake of Casey, an abortion restriction is unconstitutional if it poses an "undue burden" on a woman's right to choose abortion. Nationally renowned experts and clinic directors testified this week that the Michigan law is unnecessary to ensure informed consent for abortions and will particularly disadvantage battered women, rape and incest survivors, women carrying anomalous fetuses, and women who need abortions for severe medical and psychological conditions. CRLP attorneys Eve Gartner and Priscilla Smith represented plaintiffs during the hearing. Mandatory delay and biased counseling laws are currently in effect in Kansas, Mississippi, Nebraska, North Dakota, Ohio, Pennsylvania, and Utah; only Mississippi requires women to travel twice to a women's health care provider: once for the mandated information and a second time at least 24 hours later for the abortion. PMID:12345510

1994-06-24

110

The International Geophysical Year in Antarctica: Uncommon Collaborations, Unprecedented Results  

ERIC Educational Resources Information Center

|When 1 July 1957 ''dawned'' in the dark of the south polar night, Americans at seven scientific stations scattered across Antarctica officially began systematic, synoptic observations of the air above and ice below. Joining scientists from 11 other countries on the polar continent, they were part of the International Geophysical Year, an 18-month…

Belanger, Dian Olson

2004-01-01

111

An Australian contribution to CryoSat-II cal/val in East Antarctica including the Totten glacier region  

NASA Astrophysics Data System (ADS)

The Australian TOT-Cal project seeks to provide a contribution to the calibration and validation of the CryoSat-II mission over two adjacent important regions in East Antarctica. The first focuses on the Totten glacier, arguably one of the most important outlet glaciers in the East Antarctic, known to be undergoing significant surface lowering. The second includes the coastal slope regions behind Casey station and up on the plateau areas near Law Dome where significant spatial variation in annual accumulation is known to occur. The 2010/11 austral summer is the first field season for this project, with fieldwork to be underway at the time of the AGU FM10. In this poster, we present our current field activities and forward plans for the 2011/12 season. Our field campaign includes three components. A total of six in-situ GPS sites will be deployed over the summer period throughout the Law Dome / Totten Glacier region. These sites will facilitate the computation of the integrated water vapour content of the atmosphere, enabling an assessment against the ECMWF product used in the CyroSat-II data stream. The GPS sites also serve to provide reference stations for the AWI Polar-5 aircraft that will fly over the study area equipped with a scanning LiDAR and the ESA ASIRAS instrument. Finally, a series of kinematic GPS transects, corner cube reflector placements and surface density measurements will be undertaken from our field camp on the western flank of Law Dome to provide high resolution ground measurements for cal/val activities. In a separate project, Antarctic sea ice freeboard measurements will also contribute to the calibration and validation efforts by the Australian Antarctic program. In November 2010, the first set of such measurements will be carried out in the East Antarctic sea ice zone between 77 and 90 degrees East. The primary measurement tools for this campaign will include helicopter mounted scanning LiDAR and aerial photography, combined with in-situ sea ice observations. Over the next few austral spring seasons, similar measurements will be carried out, especially during a major marine cryosphere experiment on board the Australian RSV Aurora Australis in 2012.

Watson, C. S.; Burgette, R. J.; Tregoning, P.; Coleman, R.; Roberts, J.; Lieser, J. L.; Fricker, H. A.; Legresy, B.

2010-12-01

112

Particle-size distribution in soils of West Antarctica  

Microsoft Academic Search

The particle-size distribution in soils sampled near Russian polar stations in West Antarctica has been studied. It is shown\\u000a that the soils of the Subantarctic zone (the Bellingshausen Station on King George Island) are characterized by a higher content\\u000a of silt and clay in the fine earth fraction and by a higher content of the fine earth fraction in comparison

E. V. Abakumov

2010-01-01

113

Robert Casey  

Cancer.gov

Skip to Main Content CCR Home | About CCR | CCR Intranet Main Navigation Home Profiles Research Newsworthy References Special Interest Groups Training Main Links Psycho-Oncology Home Profiles Research Newsworthy/Resources References Special Interest

114

Living and Working in Antarctica.  

ERIC Educational Resources Information Center

|This source book, designed for 11- to 14-year-old students, seeks to describe what life is like in Antarctica. In spite of extreme weather conditions, people go to Antarctica to work every summer. Some of them stay there during the winter as well. This book seeks to supply answers to such questions as: How do people get to Antarctica? Why do they…

Kemp, Noel

115

The Annie E. Casey Foundation 2006 Kids Count Pocket Guide. State Profiles of Child Well-Being Series  

ERIC Educational Resources Information Center

Kids Count, a project of the Annie E. Casey Foundation, is a national and state by- state effort to track the status of children in the United States. By providing policymakers and citizens with benchmarks of child well-being, Kids Count seeks to enrich local, state, and national discussions concerning ways to secure better futures for all…

Annie E. Casey Foundation, 2006

2006-01-01

116

Antarctica, why so Blue?  

NASA Astrophysics Data System (ADS)

Are all fast seismic anomalies at the core-mantle boundary (CMB) created alike? Much attention has been paid to the relative variations of seismic wave speeds in slow regions of the lowermost mantle, but there is a wealth of information in the fast anomalies as well. Here we systematically characterize fast regions at the CMB in terms of their shear, compressional, and bulk wave speed anomalies and Poisson's ratio using the largest long-period catalog to date of S, ScS, Sdiff, P, and Pdiff arrival times. The fastest regions at the CMB occur beneath Antarctica, Central America, and eastern Asia. The latter two have been active subduction zones for more than 200 Ma. However, Antarctica is an exception in that subduction has not occurred there in the last 100 Ma. And, during the final stages of subduction, young oceanic lithosphere may be positively buoyant compared to the mantle and not be likely to sink all the way to the CMB. Therefore, the youngest (and thus coldest) material beneath Antarctica near the CMB is around 130 Ma in age. It is puzzling why the region beneath Antarctica would have one of the fastest seismic signals since plate reconstructions indicate that for the last 200 Ma, the greatest volume of material has been subducted under the northern Pacific. However, outside of Antarctica, the strongest fast anomalies at the CMB are geographically coincident with the current pattern of subduction, not that of the distant past. It has been noted that the seismic anomalies at the CMB do not fit those predicted by past plate reconstructions, and this mismatch has been explained in terms of the presence of the thermal boundary layer. Here, we examine thermal and compositional effects that could be produced by the interaction of subducted material with a basal thermal boundary layer, and probe how strong fast anomalies can be produced in both unexpected (Antarctica) and expected regions (eastern Asia), while fast anomalies anticipated elsewhere (northern Pacific) are diminished in amplitude.

Reif, C.; Williams, Q.; Manners, U.

2006-12-01

117

Boundary layer halogens in coastal Antarctica.  

PubMed

Halogens influence the oxidizing capacity of Earth's troposphere, and iodine oxides form ultrafine aerosols, which may have an impact on climate. We report year-round measurements of boundary layer iodine oxide and bromine oxide at the near-coastal site of Halley Station, Antarctica. Surprisingly, both species are present throughout the sunlit period and exhibit similar seasonal cycles and concentrations. The springtime peak of iodine oxide (20 parts per trillion) is the highest concentration recorded anywhere in the atmosphere. These levels of halogens cause substantial ozone depletion, as well as the rapid oxidation of dimethyl sulfide and mercury in the Antarctic boundary layer. PMID:17641195

Saiz-Lopez, Alfonso; Mahajan, Anoop S; Salmon, Rhian A; Bauguitte, Stephane J-B; Jones, Anna E; Roscoe, Howard K; Plane, John M C

2007-07-20

118

Why Is It Always Cold in Antarctica?  

NSDL National Science Digital Library

In this week-long unit, students examine weather reports from all over the world in order to understand global temperature patterns. Throughout the unit, students collect their findings in a portfolio. The comprehensive curriculum materials contain teacher tools, a Web activity in which students examine 12 months of weather data for several U.S. cities, comparing their findings with the same 12 months at Antarctica weather stations, two hands-on experiments, two Q&A interviews and a student handout with guidance for putting together their portfolios and examples of creative final projects.

119

Getting Antarctica down Cold!  

ERIC Educational Resources Information Center

|Outlines learning activities for applying geography's five fundamental themes to studying Antarctica and points out the learning potential, for studying the economic, historical, and political geography of the continent. Groups activities for grades K-5, 6-8, and 8-12. Stresses cooperative learning in general, and includes a role play activity…

Sandmeier, Kay; Greeson, Linda

1990-01-01

120

Antarctica: Discovery & Exploration.  

ERIC Educational Resources Information Center

|An examination of Antarctica, from the first sightings to the heroic explorations of the late 18th and early 19th centuries to modern-day research, is presented in this book. Twelve chapters are as follows: (1) The search begins; (2) Whalers and sealers: bites and nibbles; (3) The new continent: first sight; (4) Wintering: the first party; (5)…

Gascoigne, Toss; Collett, Peter

121

Married to Antarctica.  

ERIC Educational Resources Information Center

|A novel theory about Earth's ancient history is presented. It is proposed that North America and Antarctica once lay side by side for perhaps as long as a billion years. The importance of these continental connections to geology and other disciplines is discussed. (KR)|

Monastersky, Richard

1991-01-01

122

Antarctica: Sea Ice  

NSDL National Science Digital Library

This video segment, adapted from a NOVA broadcast, shows how sea ice forms in the Southern Ocean around Antarctica and how its seasonal fluctuation dramatically changes the continent. The segment, two minutes thirty-five seconds in length, includes rare footage of the destruction of the British ship 'Endurance', trapped and crushed by sea ice in 1914.

2010-09-30

123

POP Goes Antarctica?  

NSDL National Science Digital Library

As students explore this Web site, they will learn how scientists work together to answer questions. This site follows several scientists to Antarctica where they are doing research on Persistent Organic Pollutants. A daily journal, glossary, and learning activities will help incorporate this into classroom lesson plans.

Cowles, Susan

2002-01-01

124

ROBY goes to Antarctica  

Microsoft Academic Search

The IX Italian Expedition 1993-94 of PNRA (Programma Nazionale di Ricerche in Antartide) included the first experimental campaign in Antarctica in the field of underwater robotics. It can be described as a pilot mission to better define the role of this technology in the future of Antarctic exploration. The work plan was as follows: to test and develop the CPR-IAN

R. Bone; Giorgio Bruzzone; Massimo Caccia; Filippo Grassia; Edoardo Spirandelli; Gianmarco Veruggio

1994-01-01

125

Antarctica: Sea Ice  

NSDL National Science Digital Library

This video segment, adapted from a NOVA broadcast, shows how sea ice forms in the Southern Ocean around Antarctica and how its seasonal fluctuation dramatically changes the continent. The segment, two minutes thirty-five seconds in length, includes rare footage of the destruction of the British ship 'Endurance', trapped and crushed by sea ice in 1914.

126

Deep-water sedimentary environments of the northwestern Weddell Sea and South Sandwich Islands, Antarctica  

Microsoft Academic Search

Two transects have been sampled using short cores (multi and box), seabed photography, video sequences, and sediment profile images across the northwestern Weddell Sea and South Sandwich Forearc, Antarctica. A total of 12 core stations were examined for sediment structure, texture and composition to determine their depositional history. Four of the core stations from the Weddell Continental Slope, Abyssal Plain

John A. Howe; Tracy M. Shimmield; Robert Diaz

2004-01-01

127

Tropospheric clouds in Antarctica  

NASA Astrophysics Data System (ADS)

Compared to other regions, little is known about clouds in Antarctica. This arises in part from the challenging deployment of instrumentation in this remote and harsh environment and from the limitations of traditional satellite passive remote sensing over the polar regions. Yet clouds have a critical influence on the ice sheet's radiation budget and its surface mass balance. The extremely low temperatures, absolute humidity levels, and aerosol concentrations found in Antarctica create unique conditions for cloud formation that greatly differ from those encountered in other regions, including the Arctic. During the first decade of the 21st century, new results from field studies, the advent of cloud observations from spaceborne active sensors, and improvements in cloud parameterizations in numerical models have contributed to significant advances in our understanding of Antarctic clouds. This review covers four main topics: (1) observational methods and instruments, (2) the seasonal and interannual variability of cloud amounts, (3) the microphysical properties of clouds and aerosols, and (4) cloud representation in global and regional numerical models. Aside from a synthesis of the existing literature, novel insights are also presented. A new climatology of clouds over Antarctica and the Southern Ocean is derived from combined measurements of the CloudSat and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellites. This climatology is used to assess the forecast cloud amounts in 20th century global climate model simulations. While cloud monitoring over Antarctica from space has proved essential to the recent advances, the review concludes by emphasizing the need for additional in situ measurements.

Bromwich, David H.; Nicolas, Julien P.; Hines, Keith M.; Kay, Jennifer E.; Key, Erica L.; Lazzara, Matthew A.; Lubin, Dan; McFarquhar, Greg M.; Gorodetskaya, Irina V.; Grosvenor, Daniel P.; Lachlan-Cope, Thomas; van Lipzig, Nicole P. M.

2012-01-01

128

Antarctica and Glacial Ages  

Microsoft Academic Search

IN NATURE of September 17 there is an interesting discussion between Rev. W. S. Fleming and Prof. E. W. MacBride in regard to the Gondwana flora and glaciation in Antarctica in Permo-carboniferous times which requires some comment. Referring to the Permo-carboniferous ice age, Prof. MacBride suggests that a vast Gondwana continent in temperate parts of the southern hemisphere drifted south

A. P. Coleman

1938-01-01

129

Antarctica and Glacial Ages  

Microsoft Academic Search

IN his interesting article on ``Antarctica and Glacial Ages''1, Prof. MacBride states: ``If we add the breadth of the ice-shelf to the length of the Beardmore Glacier, we arrive at a total extent of ice-floe of about five hundred miles, and this is considerably longer than any glacier the existence of which we have evidence in the Pleistocene Glacial Age.''

J. Reid Moir

1938-01-01

130

Antarctica in Images  

NSDL National Science Digital Library

This classroom activity introduces students to Antarctica's organisms, landscapes, and seascapes. After examining the images in the photo gallery, students work in small groups to discuss their conclusions about the living conditions on this continent. The printable three-page handout includes a series of questions to help students structure their thoughts while viewing the gallery images and a group worksheet that guides students through a discussion of their evolving hypotheses and conclusions.

131

The role of women in abortion jurisprudence: from Roe to Casey and beyond.  

PubMed

The decision of the US Supreme Court in Roe vs. Wade called upon a woman's right to privacy to assert a woman's right to a previability abortion in a framework based upon a consideration of the trimester of the pregnancy. A state policy or abortion law would only survive a constitutional challenge if it passed the exacting test of serving a "compelling state interest." The Court's decision in Roe grew out of an analysis which ignored the possibility that women as individuals would be able to arrive at an abortion decision for themselves. Instead, a physician's right to exercise medical judgement and perform a first-trimester abortion upon request was upheld. The decision of the Court in Planned Parenthood of Southeastern Pennsylvania vs. Casey upheld the constitutionality of abortion but allowed states to impose abortion regulations which would only be invalid if they imposed an "undue burden" upon women. In Casey, the Court linked the abortion decision to the concept of liberty embodied in the 14th Amendment. Thus, the abortion decision is seen as solely a woman's rather than a medical decision undertaken only with the guidance of a physician. The Court acknowledged that its ruling in Roe was sound and that there was no compelling reason to overturn it. This allowed the Court to maintain its legitimacy and, thus, its authority and sense of responsibility to the people who had acted in good faith under Roe. The new "undue burden" test was applied to the Pennsylvania statutes, and the real experiences of individual women were called into play to explain why spousal notification would pose an undue burden but the informed consent requirement would not. This test will likely continue to reflect the real experiences of women and reveal the underpinnings of state regulations (such as the "repugnant" view of a woman's status within a marriage forwarded by the proposed spousal consent requirement). Unlike Roe, which resulted in delineation and polarization of the "prochoice" and "prolife" positions in the abortion debate, the "undue burden" test may achieve reconciliation of these views in light of the commonality of women's experience. PMID:8293219

Martin, P A

1993-01-01

132

Informal STEM Education in Antarctica  

NASA Astrophysics Data System (ADS)

Tourism in Antarctica has increased dramatically with tens of thousands of tourists visiting the White Continent each year. Tourism cruises to Antarctica offer a unique educational experience for lay people through informal science-technology-engineering-mathematics (STEM) education. Passengers attend numerous scientific lectures that cover topics such as the geology of Antarctica, plate tectonics, glaciology, and climate change. Furthermore, tourists experience the geology and glaciology first hand during shore excursions. Currently, the grand challenges facing our global society are closely connected to the Earth sciences. Issues such as energy, climate change, water security, and natural hazards, are consistently on the legislative docket of policymakers around the world. However, the majority of the world’s population is uninformed about the role Earth sciences play in their everyday lives. Tourism in Antarctica provides opportunities for informal STEM learning and, as a result, tourists leave with a better understanding and greater appreciation for both Antarctica and Earth sciences.

Chell, K.

2010-12-01

133

Total solar eclipse over Antarctica on 23 November 2003 and its effects on the atmosphere and snow near the ice sheet surface at Dome Fuji  

Microsoft Academic Search

The Moon cast a long shadow over Antarctica on 23 November 2003 in a total solar eclipse. The eclipse was observed at Dome Fuji Station, located at the highest point of East Dronning Maud Land, Antarctica, and lasted 1 h 41 min 37 s in a cloudless condition, during which the Sun was completely obscured for 1 min 43 s.

Takao Kameda; Koji Fujita; Okimasa Sugita; Naohiko Hirasawa; Shuhei Takahashi

2009-01-01

134

Meteorites, Ice, and Antarctica  

NASA Astrophysics Data System (ADS)

Part I. Setting the Stage: 1. Antarctica and the National Science Foundation; 2. How the project began; 3. The first three years; 4. Later years of the ANSMET Program; 5. Alone (or in small groups); Part II. ANSMET Pays Off: Field Results and their Consequences: 6. Mars on the ice; 7. Meteorites from the Moon; 8. How, and where in the Solar System?; Part III. Has it Been Worthwhile?: 9. Evaluating the collection - and speculating on its significance; 10. Meteorite stranding surfaces and the ice sheet; 11. The future: what is, is; but what will be, might not.

Cassidy, William A.

2012-03-01

135

Surface wave tomography of South America and Antarctica  

NASA Astrophysics Data System (ADS)

We present the results of a study of the dispersion characteristics of broadband fundamental mode seismic surface waves propagating across South America, Antarctica and the surrounding oceans. We analyzed data from 765 earthquakes recorded at 48 seismic stations for South America and from 576 earthquakes recorded at 44 stations for Antarctica, which produced 11,700 dispersion curves for Rayleigh Waves and 8,200 dispersion curves for Love waves. The main results of this study are represented in the form of group velocity maps for Rayleigh (20 s--175 s) and Love (20 s--125 s) waves. The South American maps reveal a number of sedimentary basins across the continent (such as Maturin-Llanos, Maranon-Ucayali-Madre de Dios, Chaco-Tarija, Parana Basins), the Caribbean, and western Gulf of Mexico; the thickened crust beneath the Andes, the Altiplano, and the Brazilian Highlands; sub-continental roots and the Galapagos Ridge and the Galapagos hot spot. The Antarctic maps demonstrate such features as the thick crust in East Antarctica and beneath the Transantarctic Mountains, mid-ocean ridges, the East Antarctic craton, and a number of hot spots. The average lateral resolution is on the order of 500--550 km on the Antarctic continent and 650--750 km on the South American continent, which is a significant improvement over that reported in global scale studies. The difference between these two results is likely due to different algorithms used to assess the resolution on the both continents. We produced azimuthal anisotropy maps for the 2psi component of group velocity across Antarctica and the surrounding oceans; these maps correlate fairly well with those of the global study (Trampert and Woodhouse, 1996). The estimated group velocity maps can be inverted to produce new shear velocity models across the studied regions, which may improve knowledge of the crust and the uppermost mantle beneath South America and Antarctica.

Vdovin, Oleg Yurevich

136

Particle-size distribution in soils of West Antarctica  

NASA Astrophysics Data System (ADS)

The particle-size distribution in soils sampled near Russian polar stations in West Antarctica has been studied. It is shown that the soils of the Subantarctic zone (the Bellingshausen Station on King George Island) are characterized by a higher content of silt and clay in the fine earth fraction and by a higher content of the fine earth fraction in comparison with the soils of the proper Antarctic tundra barrens near the Lenin-gradskaya Station and the Antarctic cold desert near the Russkaya Station. In the latter soils, the content of rock fragments is higher than that in the soils of the Antarctic tundra barrens. In the soils of the tundra barrens, a considerable accumulation of fine earth may take place in large cavities (hollows) on the stony bedrock surface. Desert pavements are formed in both types of Antarctic landscapes.

Abakumov, E. V.

2010-03-01

137

Survey of waste water disposal practices at Antarctic research stations  

Microsoft Academic Search

To inform the future practices to be employed for handling waste water and grey water at the Swedish Antarctic station, Wasa, in Dronning Maud Land, the Swedish Polar Research Secretariat took the initiative to survey the practices of the 28 nations with stations in Antarctica. A questionnaire was sent out to all members of the Antarctic Environment Officers Network during

Fredrik Gröndahl; Johan Sidenmark; Ann Thomsen

2009-01-01

138

Let's Talk with Carol Finn about Using GPS (Global Positioning System) to Study Ice and Geology in Antarctica  

NSDL National Science Digital Library

In this interview, a geophysicist working in Antarctica describes her work reading the magnetic data of Antarctic rocks that lie below the ice's surface. She discusses her area of study, the Transantarctic Mountains near Byrd station, her study methods, and why her work is important. There is also a brief summary of personal information, and some advice for students about studying and conservation in Antarctica.

139

Energy efficiency and renewable energy under extreme conditions: Case studies from Antarctica  

Microsoft Academic Search

This article showcases a range of small and large scale energy efficiency and renewable energy deployments at Antarctic research stations and field camps. Due to the cold and harsh environment, significant amounts of fuel are needed to support humans working and living in Antarctica. The purchase, transportation and storage of large amounts of fossil fuel entail significant economic costs and

Tina Tin; Benjamin K. Sovacool; David Blake; Peter Magill; Saad El Naggar; Sven Lidstrom; Kenji Ishizawa; Johan Berte

2010-01-01

140

Impacts of geoscience research on the physical environment of the Vestfold Hills, Antarctica  

Microsoft Academic Search

Antarctic polar deserts can be of considerable scientific interest, but can also exhibit great environmental sensitivity. A variety of factors, including Australia's legal obligations under the Madrid Protocol, public expectations, certain research opportunities and ethical considerations, demand a very high standard of environmental protection. A survey outside the Davis Station limits in the Vestfold Hills, East Antarctica, identified 66 sites

K. Kiernan; A. McConnell

2001-01-01

141

Debris accumulation on oceanic island shores of the Scotia Arc, Antarctica  

Microsoft Academic Search

The oceanic islands in the Southern Ocean can be considered amongst the remotest shores as, not only are they uninhabited (except for small research stations) and geographically isolated, but they are also enclosed by the oceanographic barrier of the Polar Frontal Zone. We survey island shores in the Scotia Arc mountain chain linking Antarctica to South America, including South Georgia,

P. Convey; D. Barnes; A. Morton

2002-01-01

142

Benthic infaunal communities across the Weddell Sea Basin and South Sandwich Slope, Antarctica  

Microsoft Academic Search

The present study represents the first quantitative investigation of deep-sea benthic infauna in Antarctica. Box cores and multicores were used to collect sediment from 12 stations across the slope and abyssal basin of the Weddell Sea and the slope off the South Sandwich Islands, including sites in the South Sandwich Trench (6300m). The multicore was a more efficient sampler than

James A. Blake; Bhavani E. Narayanaswamy

2004-01-01

143

Benthic infaunal communities across the Weddell Sea Basin and South Sandwich Slope, Antarctica  

Microsoft Academic Search

The present study represents the first quantitative investigation of deep-sea benthic infauna in Antarctica. Box cores and multicores were used to collect sediment from 12 stations across the slope and abyssal basin of the Weddell Sea and the slope off the South Sandwich Islands, including sites in the South Sandwich Trench (6300 m). The multicore was a more efficient sampler

James A. Blake; Bhavani E. Narayanaswamy

2004-01-01

144

Evaluation of DNA Dosimetry to Assess Ozone-Mediated Variability of Biologically Harmful Radiation in Antarctica  

Microsoft Academic Search

ABSTRACT In this study we investigated the use of a DNA dosimeter to accurately measure changes in ultraviolet B radiation (UVBR; 280?315 nm) under Antarctic ozone hole con- ditions. Naked DNA solution in quartz tubes was exposed to ambient solar radiation at Rothera Research Station, Antarctica, between October and December 1998 for 3 h during UVBR peak hours (1200?1500 h).

Alison L. George; Helen J. Peat; Anita G. J. Buma

2002-01-01

145

An analysis of temperatures and wind speeds above Dome C, Antarctica  

Microsoft Academic Search

A good astronomical site must fulfill several criteria including low atmospheric turbulence and low wind speeds. It is therefore important to have a detailed knowledge of the temperature and wind conditions of a location considered for future astronomical research. Antarctica has unique atmospheric conditions that have already been exploited at the South Pole station. Dome C, a site located on

E. Aristidi; K. Agabi; M. Azouit; E. Fossat; J. Vernin; T. Travouillon; C. Meyer; J. W. V. Storey; B. Halter; W. L. Roth; V. Walden

2005-01-01

146

Snow chemistry across Antarctica  

NASA Astrophysics Data System (ADS)

An updated compilation of published and new data of major-ion (Ca, Cl, K, Mg, Na, NO3, SO4) and methylsulfonate (MS) concentrations in snow from 520 Antarctic sites is provided by the national ITASE (International Trans-Antarctic Scientific Expedition) programmes of Australia, Brazil, China, Germany, Italy, Japan, Korea, New Zealand, Norway, the United Kingdom, the United States and the national Antarctic programme of Finland. The comparison shows that snow chemistry concentrations vary by up to four orders of magnitude across Antarctica and exhibit distinct geographical patterns. The Antarctic-wide comparison of glaciochemical records provides a unique opportunity to improve our understanding of the fundamental factors that ultimately control the chemistry of snow or ice samples. This paper aims to initiate data compilation and administration in order to provide a framework for facilitation of Antarctic-wide snow chemistry discussions across all ITASE nations and other contributing groups. The data are made available through the ITASE web page (http://www2.umaine.edu/itase/content/syngroups/snowchem.html) and will be updated with new data as they are provided. In addition, recommendations for future research efforts are summarized.

Bertler, N.; Mayewski, P. A.; Aristarain, A.; Barrett, P.; Becagli, S.; Bernardo, R.; Bo, S.; Xiao, C.; Curran, M.; Qin, D.; Dixon, D.; Ferron, F.; Fischer, H.; Frey, M.; Frezzotti, M.; Fundel, F.; Genthon, C.; Gragnani, R.; Hamilton, G.; Handley, M.; Hong, S.; Isaksson, E.; Kang, J.; Ren, J.; Kamiyama, K.; Kanamori, S.; Kärkäs, E.; Karlöf, L.; Kaspari, S.; Kreutz, K.; Kurbatov, A.; Meyerson, E.; Ming, Y.; Zhang, M.; Motoyama, H.; Mulvaney, R.; Oerter, H.; Osterberg, E.; Proposito, M.; Pyne, A.; Ruth, U.; Simões, J.; Smith, B.; Sneed, S.; Teinilä, K.; Traufetter, F.; Udisti, R.; Virkkula, A.; Watanabe, O.; Williamson, B.; Winther, J.-G.; Li, Y.; Wolff, E.; Li, Z.; Zielinski, A.

147

Carbonaceous micrometeorites from Antarctica.  

PubMed

Over 100 000 large interplanetary dust particles in the 50-500 micrometers size range have been recovered in clean conditions from approximately 600 tons of Antarctic melt ice water as both unmelted and partially melted/dehydrated micrometeorites and cosmic spherules. Flux measurements in both the Greenland and Antarctica ice sheets indicate that the micrometeorites deliver to the Earth's surface approximately 2000x more extraterrestrial material than brought by meteorites. Mineralogical and chemical studies of Antarctic micrometeorites indicate that they are only related to the relatively rare CM and CR carbonaceous chondrite groups, being mostly chondritic carbonaceous objects composed of highly unequilibrated assemblages of anhydrous and hydrous minerals. However, there are also marked differences between these two families of solar system objects, including higher C/O ratios and a very marked depletion of chondrules in micrometeorite matter; hence, they are "chondrites-without-chondrules." Thus, the parent meteoroids of micrometeorites represent a dominant and new population of solar system objects, probably formed in the outer solar system and delivered to the inner solar system by the most appropriate vehicles, comets. One of the major purposes of this paper is to discuss applications of micrometeorite studies that have been previously presented to exobiologists but deal with the synthesis of prebiotic molecules on the early Earth, and more recently, with the early history of the solar system. PMID:11543069

Engrand, C; Maurette, M

1998-07-01

148

IPY: Engaging Antarctica: Bringing Antarctic Geoscience to the Public Through a NOVA Documentary and an Innovative Flexible Exhibit for Informal Science Education Venues  

NASA Astrophysics Data System (ADS)

IPY: Engaging Antarctica is an informal science education project designed to increase the general public's understanding of scientific research conducted in Antarctica. The project focuses specifically on the multi- national, NSF-funded Antarctic Drilling Project (ANDRILL). The ANDRILL project is the newest geological drilling program in an ongoing effort to recover stratigraphic records from Antarctica. ANDRILL's primary objectives are to investigate Antarctica's role in global environmental change over the past 65 million years and to better understand its future response to global changes. Additionally, through ANDRILL's Research Immersion for Science Educators program (ARISE), 12 science educators from four countries will work on science research teams in Antarctica and produce educational materials that feature Antarctic geoscience. The Engaging Antarctica project will produce both a NOVA television documentary and an innovative informal learning exhibit. The documentary, Antarctica's Icy Secrets, will provide a geological perspective on how Antarctica continues to play a major role in affecting global climate by altering ocean currents and sea levels. The learning exhibit, one that blends standards- and inquiry-based learning with the latest information technologies, is coined the Flexhibit. The Engaging Antarctica Flexhibit will provide a digital package of high resolution images for banners as well as learning activities and ideas for exhibit stations that can be implemented by youth groups. Flexhibit images will feature ANDRILL scientists at work, and audio files, available as podcasts, will tell scientists' stories in their own words, speaking directly to the public about the joys and challenges of Antarctic geological research.

Rack, F.; Diamond, J.; Levy, R.; Berg, M.; Dahlman, L.; Jackson, J.

2006-12-01

149

Research on the Web: Antarctic Weather Stations  

NSDL National Science Digital Library

This Web research activity helps students see the link between wind speeds and geographical features. All directions are included in a printable handout. Students begin by gathering wind-speed measurements for 10 weather stations in Antarctica, converting the data, as needed, to allow comparisons. Next, they record wind data for five consecutive days and calculate the average wind speed for each station. They then examine elevation data for the 10 weather stations. They end by developing a hypothesis for the different patterns they've observed.

150

Auroral observations at the Mario Zucchelli Base (Antarctica). Morphological features.  

NASA Astrophysics Data System (ADS)

Auroral displays are the visible manifestation of the solar wind-magnetosphere-ionosphere interaction at the high latitude polar regions. The study of this phenomenon is very relevant for both the investigation of the magnetosphere-ionosphere coupling and the comprehension of the overall magnetospheric dynamics during the so-called magnetic substorms. Here, we present some preliminary results on the morphological features of the auroral emission as observed at the Mario Zucchelli station in Antarctica during a recent winter campaign. In particular, we are going to show how the morphology of the auroral emission changes with the wavelength (630.0 nm, 557.7 nm and 427.8 nm).

Consolini, G.; Balsamo, E. P.; Candidi, M.; De Michelis, P.; Marcucci, M. F.; Morici, L.

151

Remote sensing and skywave digital communication from antarctica.  

PubMed

This paper presents an overview of the research activities undertaken by La Salle and the Ebro Observatory in the field of remote sensing. On 2003 we started a research project with two main objectives: implement a long-haul oblique ionospheric sounder and transmit the data from remote sensors located at the Spanish Antarctic station Juan Carlos I to Spain. The paper focuses on a study of feasibility of two possible physical layer candidates for the skywave link between both points. A DS-SS based solution and an OFDM based solution are considered to achieve a reliable low-power low-rate communication system between Antarctica and Spain. PMID:22303166

Bergadà, Pau; Deumal, Marc; Vilella, Carles; Regué, Joan R; Altadill, David; Marsal, Santi

2009-12-14

152

Remote Sensing and Skywave Digital Communication from Antarctica  

PubMed Central

This paper presents an overview of the research activities undertaken by La Salle and the Ebro Observatory in the field of remote sensing. On 2003 we started a research project with two main objectives: implement a long-haul oblique ionospheric sounder and transmit the data from remote sensors located at the Spanish Antarctic station Juan Carlos I to Spain. The paper focuses on a study of feasibility of two possible physical layer candidates for the skywave link between both points. A DS-SS based solution and an OFDM based solution are considered to achieve a reliable low-power low-rate communication system between Antarctica and Spain.

Bergada, Pau; Deumal, Marc; Vilella, Carles; Regue, Joan R.; Altadill, David; Marsal, Santi

2009-01-01

153

[Search for psychrophilic methylotrophic bacteria in biotopes of the Antarctica].  

PubMed

Psychrotolerant bacteria which use obligately methane were found in the moss samples and in soil-vegetation samples in the island part of the Antarctica during the VII expedition (2003) at the station "Akademik Vernadsky". The number of methane-oxidizing bacteria in the samples from the Antarctica (101- 10(3)/g of the sample) was lower than in the samples from the regions with moderate climate (10(2)- 106/g of the sample). Psychrotolerant strains of Methylobacteriium genus which use facultatively methanol were found in the bottom sediments of the fresh-water and Krasnoye lakes, as well as in the soil-plant samples. The psychrophilic strain which is probably a new species of the genus Methylobacterium has been isolated from one soil-plant sample from the Antarctica at 10 degrees C. It is established that most collection mesophilic strains of Methylobacterium, which have been isolated from the soil and plant phyllosphere in Ukraine, also could grow at 10 degrees C. PMID:16018200

Romanovskaia, V A; Shilin, S O; Chernaia, N A; Tashirev, A B; Malashenko, Iu R; Rokitko, P V

154

Comparison of Tropospheric Water Vapour over Antarctica Derived from AMSU-B Data, Ground-Based GPS Data and the NCEP\\/NCAR Reanalysis  

Microsoft Academic Search

The extreme climate conditions and the sparse number of research stations in Antarctica limit the number of meteorological records over this area. Satellite radiometric measurements and ground-based GPS measurements can therefore improve the amount of available water vapour information. Combining the Zenith Total Delay (ZTD) time series from 6 Antarctic GPS stations and surface meteorological data, we have determined Precipitable

Sibylle VEY; R DIETRICH; K.-P JOHNSEN; Jibylle MIAO; G HEYGSTER

2004-01-01

155

Fecal Coliforms in Antarctica  

NSDL National Science Digital Library

In this interrupted case study, students explore the environmental consequences of Antarctic research as they design experiments to assess the impact of disposing untreated sewage from a research station into the ocean. Students review experimental methods to measure coliform bacteria, examine data, and decide what actions, if any, should be taken. The can be used in either a non-majors course in science literacy or a general microbiology class studying bacterial detection methods. For non-majors, the instructor would emphasize the mechanics of data collection and analysis and may touch on the environmental implications of finding fecal coliforms in Antarctic waters. For microbiology students, the instructor would highlight the bacteriology and pair the case with a lab.

Nold, Stephen C.

2002-01-01

156

Pieces of Laurentia in East Antarctica  

Microsoft Academic Search

East Antarctica figures prominently as a central cratonic piece in reconstructions of the Neoproterozoic supercontinent Rodinia, yet these fits variously position East Antarctica next to (so-called SWEAT fit), or distant from, the western margin of Laurentia. Paleomagnetic poles are lacking for East Antarctica during the time period between assembly at about 1.3-1.1 Ga and subsequent breakup by 700-650 Ma, and

J. W. Goodge; J. D. Vervoort; D. M. Brecke; C. M. Fanning; I. S. Williams; P. Myrow; S. A. Dufrane

2007-01-01

157

HalleyVI - a station for science  

NASA Astrophysics Data System (ADS)

There has been a research station at Halley in Antarctica (75°35'S, 26°34'W) since 1956. Halley has a long and successful scientific record, notably the discovery of the Ozone Hole and significant contributions to areas as diverse as Geology and Space physics. Halley is located on a floating and flowing iceshelf with constant surface accumulation. These conditions have resulted in the necessary regular rebuilding of the station and HalleyVI has just been completed. Halley VI has been fully scientifically operational since Feb 2012. The station supports a chemical and turbulence clean area, an electromagnetic quiet zone, an area for radars, and flexible facilities on the station to support a wide variety of science activities. This presentation outlines the major features of the new station, its current scientific activities, and the facilities that allow the hosting of a wide variety of scientific experiments.

Rose, Mike; Tuplin, Karl

2013-04-01

158

On the terms of geomagnetic daily variation in Antarctica  

NASA Astrophysics Data System (ADS)

The target of this work is to investigate the nature of magnetic perturbations produced by ionospheric and magnetospheric currents as recorded at high-latitude geomagnetic stations. In particular, we investigate the effects of these currents on geomagnetic data recorded in Antarctica. To this purpose we apply a mathematical method, known as Natural Orthogonal Composition, to analyze the magnetic field disturbances along the three geomagnetic field components (X, Y and Z) recorded at Mario Zucchelli Station (IAGA code TNB; geographic coordinates: 74.7° S, 164.1° E) from 1995 to 1998. Using this type of analysis, we characterize the dominant modes of the geomagnetic field daily variability through a set of empirical orthogonal functions (EOFs). While such mathematically independent EOFs do not necessarily represent physically independent modes of variability, we find that some of them are actually related to well known current patterns located at high latitudes.

de Michelis, P.; Tozzi, R.; Meloni, A.

2009-06-01

159

Putting Antarctica on the Map  

NSDL National Science Digital Library

This six-day unit has students examine historical maps of Antarctica and research early explorers to gain perspective on how cartography and our understanding of the globe have changed. The curriculum materials contain teacher tools including individually downloadable readings, detailed daily breakdowns of tasks, teacher strategies for using the activities, a portfolio grading sheet, a project rubric sheet, and supplemental readings. In addition, a Web activity in which students examine and compare historical maps and their modern-day equivalents, highlights how map-making techniques have changed. A classroom activity in which students examine the history of Antarctic exploration and conduct research on a topic of interest and several readings that provide a broad perspective, including excerpts from early explorers' journals and an interview with a marine biologist who studies the history of Antarctica, round out the unit. A student handout provides guidance for putting together student portfolios and examples of creative final projects.

160

CONCORDIASI, Long Duration Stratospheric Balloons over Antarctica  

NASA Astrophysics Data System (ADS)

CNES, the French space agency, has been developing and operating stratospheric balloons for scientific purposes for many years. One particular type of balloon has been designed for ultra long duration flights in the lowermost stratosphere: the superpressure balloon. A constellation of typically 10 to 20 balloons, fitted with light payloads can be deployed, forming a regional airborne observatory. The first use of this kind of observation system has been for atmospheric sciences, each of the balloons carrying various sets of scientific instruments. Concordiasi is the latest program built on the use of this observation system in its most recent development stage. 19 balloons were released from McMurdo Station Antarctica over September to October 2010 in the Winter Polar Vortex. It carried a variety of instruments, for remote and in-situ measurement of the atmosphere. The average flight duration of the balloons was 69 days, cumulating to 1316 days over the whole balloon constellation. We will present briefly the scientific objectives of the project; describe the flight system and the flight campaign, including the launch phase and the long flight monitoring through the control centres. Flight results will be presented, with an overview of the scientific results, but focussing mainly on the technical achievements and on lessons that can be drawn from this project.

Cocquerez, Philippe

2012-07-01

161

Antarctica: Prospects for Palaeoclimatic studies  

Microsoft Academic Search

Abstract Despite the fact the greater part of the rocky foundation of Antarctica is hidden beneath the huge ice sheet, enough can be seen along the Transantarctic Mountains in the Antarctic Peninsula, and around the edges of the east Antarctic ice cap. The geologists and other associated scientists are,very ,interested ,in the ,continent which,forms ,one ,of the ,earth's seven major,rock

S K. BERA; A K SINHA; Birbal Sahni

162

Seismic anisotropy of the Victoria Land region, Antarctica  

NASA Astrophysics Data System (ADS)

We present shear wave splitting results obtained from the analysis of core-refracted teleseismic phases recorded by permanent and temporary seismographic stations located in the Victoria Land region (Antarctica). We use an eigenvalue technique to isolate the rotated and shifted shear wave particle motion, to determine the best splitting parameters. Average values show clearly that dominant fast axis direction is NE-SW oriented, in accordance with previous measurements obtained around this zone. Only two stations, OHG and STAR, show different orientations, with N-S and NNW-SSE main directions. On the basis of the periodicity of single shear wave splitting measurements with respect to backazimuths of events under study, we infer the presence of lateral and vertical changes in the deep anisotropy direction. To test this hypothesis we model waveforms using a cross-convolution technique for the cases of one and two anisotropic layers. We obtain a significant improvement on the misfit in the double layer case for the two stations. For stations where a multilayer structure does not fit, we investigate lateral anisotropy changes at depth through Fresnel zone computation. We find that anisotropy beneath the Transantarctic Mountains (TAM) is considerably different from that beneath the Ross Sea. This feature influences the measurement distribution for the two permanent stations TNV and VNDA. Our results show a dominant NE-SW direction over the entire region, however other anisotropy directions are present and maybe interpreted in the context of regional tectonics.

Salimbeni, S.; Pondrelli, S.; Danesi, S.; Morelli, A.

2010-07-01

163

Soils of Marie Byrd Land, West Antarctica  

NASA Astrophysics Data System (ADS)

Soils of Marie Byrd Land-one of the remotest and difficultly accessible regions of Antarctica-were investigated in the area of the mothballed Russkaya station located to the south of 74° S. Despite the extremely severe wind regime (the average wind velocity is 13 m/s, and the maximum wind velocity is up to 60 m/s), the projective cover of vegetation in the area of the station averages 25-40% and reaches 60-80% in some places. The phenomena of physical weathering of the bedrock-exfoliation, stone pavements, residual rocks exposed by wind (hoodoos), and others-are clearly manifested. In most of the described soils, normal organic and organomineral horizons are absent. The soil profiles represent the mixture of the residues of mosses and lichens and the gravelly eluvium. The fine earth material is blown out of the surface horizons by strong winds; its residual accumulation takes place in the middle and lower parts of the profiles. The classification position of these soils is open to argument; they are close to Petrozems and Lithozems. Most of the profiles are underlain by the massive or slightly disintegrated bedrock with dry permafrost at a depth of 20 to 50 cm. Soils with dry permafrost comprise about 75% of the surveyed area. In separate loci in the depressions of the local mesorelief and on gentle slopes, the soils with clearly expressed cryoturbation features are developed; their profiles are underlain by the ice-rich permafrost and compose about 15% of the surveyed area. Anthropogenically disturbed soils and soils polluted with petroleum hydrocarbons, heavy metals, and other pollutants occupy about 10% of the surveyed area.

Lupachev, A. V.; Abakumov, E. V.

2013-10-01

164

Microgeographic variation and songs in the underwater vocalisation repertoire of the Weddell seal ( Leptonychotes weddellii ) from the Vestfold Hills, Antarctica  

Microsoft Academic Search

Recordings of underwater vocalisations of the Weddell seal (Leptonychotes weddellii) were made in fjords of the Vestfold Hills near Davis Station, Antarctica. The repertoire was examined for the presence of microgeographic variation. Recordings covered the period from the end of mating to the beginning of the moult in the 1989\\/1990 breeding season. The repertoire was classified into 44 vocalisation types

M. G. Morrice; H. R. Burton; K. Green

1994-01-01

165

A Pc 1 Pearl Wave Event Observed at Halley, Antarctica and by the Cluster Spacecraft in the Inner Magnetosphere  

Microsoft Academic Search

A three-axis search coil magnetometer was deployed at the Halley research station near the coast of Antarctica (L = 4.2) in February 2005. We report here on some of the initial observations of Pc 1 and 2 waves recorded at this site, and in particular on selected events observed simultaneously by one or more of the four Cluster spacecraft during

M. J. Engebretson; J. L. Posch; M. R. Lessard; M. C. Rose; R. B. Horne; K. Fornacon; K. Glassmeier

2006-01-01

166

LICHENS GROWING ON GLASS IN ANTARCTICA  

Microsoft Academic Search

Early stages of lichen colonization on glass are reported for the first time from Antarctica. In the initial establishment of the lichen thallus rhizomorphs play an important role for the attachment to the substratum and the exploitation of nutrient and photobiont resources. The micrographs presented indicate that in Antarctica colonization of bare substrata by lichens is not necessarily an extremely

B. SCHROETER; L. G. SANCHO

1996-01-01

167

Station Models  

NSDL National Science Digital Library

This project will allow users to become acquainted with station models that are found on weather maps. Students will study the various atmospheric variables that are depicted on a station model and then practice on an interactive station model program. Part 1 - Being able to read and interpret weather maps is a very important skill in meteorology. One of the most basic skills of predicting the weather is being able to interpret a station model of a given location. A station model is a bundle of information that ...

Ertl, Mr.

2007-11-03

168

Seasonal and interannual variability in temperature, chlorophyll and macronutrients in northern Marguerite Bay, Antarctica  

Microsoft Academic Search

We report data from the first 8 years of oceanographic monitoring in Ryder Bay, northern Marguerite Bay, Antarctica. These data form the oceanographic component of the Rothera Oceanographic and Biological Time-Series (RaTS) project. When weather and ice permit, the RaTS station is occupied every 5 days in summer and weekly in winter. Observations comprise a conductivity–temperature–depth (CTD) cast to 500m

Andrew Clarke; Michael P. Meredith; Margaret I. Wallace; Mark A. Brandon; David N. Thomas

2008-01-01

169

Macrofaunal shallow benthic communities along a discontinuous annual cycle at Admiralty Bay, King George Island, Antarctica  

Microsoft Academic Search

Temporal variations in composition and density of the benthic macrofauna at two stations (12 and 25 m depth) were studied\\u000a in Admiralty Bay, King George Island, Antarctica. Samples where carried out using an van Veen sampler between March and December\\u000a 1999 (winter) and December 2000 and March 2001 (summer), comprising a discontinuous annual cycle. Sediment organic matter\\u000a showed a marked seasonal

C. A. Echeverría; P. C. Paiva

2006-01-01

170

VELOX: a new VLF\\/ELF receiver in Antarctica for the Global Geospace Science mission  

Microsoft Academic Search

VELOX (VLF\\/ELF Logger Experiment), a new facility for systematically studying the characteristics of magnetospherically generated ELF\\/VLF radio noise received at a high-latitude ground station (Halley, Antarctica, 76°S, 26°W, L = 4.3), measures continuously at 1 s resolution the absolute power (peak, mean, and minimum), arrival azimuth, and polarisation ellipticity in 8 logarithmically spaced frequency bands ranging from 500 Hz to

A. J. Smith

1995-01-01

171

Sterols and fecal indicator microorganisms in sediments from Admiralty Bay, Antarctica  

Microsoft Academic Search

A B S T R A C T Sediments from the proximity of Ferraz station outfall, located in Admiralty Bay, Antarctica, were analyzed for fecal indicator microorganisms and sterols during the austral summer of 1999\\/2000 in order to assess human sewage input. Concentrations of total sterols and coprostanol ranged from 0.09 to 19.6 µg.g -1 and < 0.01 and 14.0

César de Castro Martins; Rosalinda Carmela Montone; Rosa Carvalho Gamba; Vivian Helena Pellizari

2005-01-01

172

First complete season of PMSE observations above Davis, Antarctica, and their relation to winds and temperatures  

Microsoft Academic Search

A comprehensive account of the properties of southern hemisphere (SH) Polar Mesosphere Summer Echoes (PMSE) has been constrained by the lack of deployment of atmospheric radars. Here we present the first complete season of PMSE detected above the high-latitude station Davis, Antarctica (78.0°E, 68.6°S) using a 55-MHz atmospheric radar for the 2004–2005 austral summer. We present the characteristics and morphology

Ray J. Morris; Damian J. Murphy; Andrew R. Klekociuk; David A. Holdsworth

2007-01-01

173

Analysis of a regional change in the sign of the SAM–temperature relationship in Antarctica  

Microsoft Academic Search

This study examines regional atmospheric circulation changes associated with a reversal in the sign of the relationship between\\u000a the Southern Annular Mode (SAM) and near-surface temperatures at Halley station, East Antarctica, during the 1980s. We show\\u000a that the key factor affecting the regional SAM–temperature relationship (STR) is the relative magnitude of two climatological\\u000a low pressure centres to the west and

Gareth J. Marshall; Stefano Di Battista; Sushant S. Naik; Meloth Thamban

2011-01-01

174

Analysis of a regional change in the sign of the SAM-temperature relationship in Antarctica  

Microsoft Academic Search

This study examines regional atmospheric circulation changes associated with a reversal in the sign of the relationship between the Southern Annular Mode (SAM) and near-surface temperatures at Halley station, East Antarctica, during the 1980s. We show that the key factor affecting the regional SAM-temperature relationship (STR) is the relative magnitude of two climatological low pressure centres to the west and

Gareth J. Marshall; Stefano di Battista; Sushant S. Naik; Meloth Thamban

2011-01-01

175

Distribution patterns of benthic microalgal standing stock at McMurdo Sound, Antarctica  

Microsoft Academic Search

During the austral summer of 1975–76 and winter of 1977 benthic and water column chlorophyll a and phaeopigments were measured at several sites along the east and west sides of McMurdo Sound, Antarctica. Estimates of in situ primary productivity were made at some McMurdo Sound locations. Additionally, water column samples were collected at 5 stations in the Ross Sea during

Paul K. Dayton; Daniel Watson; Anna Palmisano; James P. Barry; John S. Oliver; Diego Rivera I

1986-01-01

176

Composite Ice Sheet Temperature Record From In Situ and Satellite Data Sets, Siple Dome, West Antarctica  

Microsoft Academic Search

During December 1996, ice core drilling activities were begun at Siple Dome, West Antarctica. In January 1997, the University of Wisconsin installed an automatic weather station (AWS) at Siple Dome as part of its Antarctic Meteorological Research Center?s (http:\\/\\/uwamrc.ssec.wisc.edu\\/aws\\/) network of instruments. A multi-year to decadal-length temperature record is needed to accurately calibrate ice core proxy temperature data (stable isotopes

C. A. Shuman; J. C. Comiso; L. Stock; V. Suchdeo

2002-01-01

177

Measurements of positive ions and air-earth current density at Maitri, Antarctica  

Microsoft Academic Search

Simultaneous measurements of the small-, intermediate- and large- positive\\u000aions and air earth current density made at a coastal station, Maitri at\\u000aAntarctica during January to February 2005, are reported. Although, small and\\u000alarge positive ion concentrations do not show any systematic diurnal\\u000avariations, variations in them are almost similar to each other. On the other\\u000ahand, variations in intermediate

Vimlesh Pant; A. K. Kamra

2009-01-01

178

Measurements of positive ions and air-Earth current density at Maitri, Antarctica  

Microsoft Academic Search

Simultaneous measurements of the small, intermediate and large positive ions and air-Earth current density made at a coastal station, Maitri (70°45?52?S, 11°44?03?E, 130 m above sea level), at Antarctica during January–February 2005, are reported. Although small and large positive ion concentrations do not show any systematic diurnal variations, variations in them are almost similar to each other. On the other

Devendraa Siingh; Vimlesh Pant; A. K. Kamra

2007-01-01

179

Time-Series Trends of Trace Elements in AN Ice Core from Antarctica  

Microsoft Academic Search

Trace element measurements were made by instrumental neutron activation analysis on stratigraphically dated ice core samples from Byrd Station, Antarctica, to determine the concentration levels of natural and anthropogenic substances. Sampling was continuous between 1926 A.D. and 1989 A.D. and selective between 1711 A.D. and 1926 A.D. Twenty-one elements with concentrations above the detection limits were determined. The time period

Siddik Sinan Keskin

1995-01-01

180

Potential methane reservoirs beneath Antarctica.  

PubMed

Once thought to be devoid of life, the ice-covered parts of Antarctica are now known to be a reservoir of metabolically active microbial cells and organic carbon. The potential for methanogenic archaea to support the degradation of organic carbon to methane beneath the ice, however, has not yet been evaluated. Large sedimentary basins containing marine sequences up to 14?kilometres thick and an estimated 21,000 petagrams (1?Pg equals 10(15)?g) of organic carbon are buried beneath the Antarctic Ice Sheet. No data exist for rates of methanogenesis in sub-Antarctic marine sediments. Here we present experimental data from other subglacial environments that demonstrate the potential for overridden organic matter beneath glacial systems to produce methane. We also numerically simulate the accumulation of methane in Antarctic sedimentary basins using an established one-dimensional hydrate model and show that pressure/temperature conditions favour methane hydrate formation down to sediment depths of about 300?metres in West Antarctica and 700?metres in East Antarctica. Our results demonstrate the potential for methane hydrate accumulation in Antarctic sedimentary basins, where the total inventory depends on rates of organic carbon degradation and conditions at the ice-sheet bed. We calculate that the sub-Antarctic hydrate inventory could be of the same order of magnitude as that of recent estimates made for Arctic permafrost. Our findings suggest that the Antarctic Ice Sheet may be a neglected but important component of the global methane budget, with the potential to act as a positive feedback on climate warming during ice-sheet wastage. PMID:22932387

Wadham, J L; Arndt, S; Tulaczyk, S; Stibal, M; Tranter, M; Telling, J; Lis, G P; Lawson, E; Ridgwell, A; Dubnick, A; Sharp, M J; Anesio, A M; Butler, C E H

2012-08-30

181

Putting Antarctica on the Map  

NSDL National Science Digital Library

In this six-day unit, students examine historical maps of Antarctica and research early explorers to gain perspective on how cartography and our understanding of the globe have changed. Throughout the unit, students collect their findings in a portfolio. The comprehensive curriculum materials contain teacher tools, which include individually downloadable readings, detailed daily breakdowns of tasks, teacher strategies for using the activities, a portfolio grading sheet, a project rubric sheet, and additional readings; a Web activity in which students examine and compare historical maps and their modern-day equivalents, focusing on how map-making techniques have changed; a classroom activity in which, over the course of three days, students examine the history of Antarctic exploration and conduct research on a topic of interest; several readings that provide a broad perspective, including excerpts from early explorers' journals and a Q&A interview with a marine biologist who studies the history of Antarctica and a student handout with guidance for putting together their portfolios and examples of creative final projects.

182

SEISMIC ANISOTROPY ANALYSIS IN THE VICTORIA LAND REGION (ANTARCTICA)  

NASA Astrophysics Data System (ADS)

We present here shear wave splitting results obtained from analysis of core refracted teleseismic phases in the Victoria Land region (Antarctica). We used data belonging to permanent and temporary stations in the area. The temporary stations are located around the David Glaciers and installation is part of two expeditions inside the Italian National Antarctic program (PNRA, Programma Nazionale di Ricerche in Antartide). The network was composed by 8 seismic stations, located on rocky outcrops around the glacier, and has been active from November 2003 to February 2004, and from November 2005 to February 2006. One of this (STAR) became permanent on 2004 and data until 2007 are analyzed. We use eigenvalue technique of Silver and Chan (1991) to linearize the rotated and shifted shear wave particle motions and determine the best splitting parameters. Scattered distribution of single shear-wave measurements is obtained. Null measurements follow the same distribution. Average measurements show clearly that the main anisotropy direction is NE-SW, accordingly with previous measurements obtained around this zone. Only two stations, OHG and STAR, have a different orientation and a N-S and NNW-SSE main directions are obtained respectively. The distribution of single shear-wave splitting measurements evidenced periodicity respect the back-azimuth of the events analyzed, therefore a possible two layers anisotropic structures could be supposed. To test this hypothesis we used the Menke and Levin (2003) code that allow to model waveforms using a cross convolution technique in one and two layer's cases. Significant improvements of the misfit in the double layer case allow choosing this more complex model. The one layer structure is the best for permanent stations TNV and VNDA with directions and delay time accordingly with average measurements. The double layer models fit better the data on stations STAR, located near the coast, and OHG located inland, and show in both cases the same contribution of the anisotropy.

Salimbeni, S.; Pondrelli, S.; Danesi, S.; Morelli, A.

2009-12-01

183

The Landsat Image Mosaic of Antarctica (LIMA)  

NSDL National Science Digital Library

By studying Antarctica via satellite and through ground-truthing research, we can learn where the ice is melting and why. The Landsat Image Mosaic of Antarctica (LIMA), a new and cutting-edge way for scientists, researchers, educators, students, and the public to look at Antarctica, supports this research and allows for unprecedented views of our coldest and driest landmass. This article discusses LIMA, presents two LIMA-based classroom activities, and calls for science teachers to create additional related activities for classrooms around the world.

Campbell, Brian; Bindschadler, Robert

2009-01-01

184

Lithospheric Structure of Antarctica and Implications for Geological and Cryospheric Evolution  

NASA Astrophysics Data System (ADS)

Recent broadband seismic deployments, including the AGAP/GAMSEIS array of 24 broadband seismographs over the Gamburtsev Subglacial Mountains (GSM) in East Antarctica and the POLENET/ANET deployment of 33 seismographs across much of West Antarctica, reveal the detailed crust and upper mantle structure of Antarctica for the first time. The seismographs operate year-around even in the coldest parts of Antarctica, due to novel insulated boxes, power systems, and modified instrumentation developed in collaboration with the IRIS PASSCAL Instrument Center. We analyze the data using several different techniques to develop high-resolution models of Antarctic seismic structure. We use Rayleigh wave phase velocities at periods of 20-180 s determined using a modified two-plane wave decomposition of teleseismic Rayleigh waves to invert for the three dimensional shear velocity structure. In addition, Rayleigh wave group and phase velocities obtained by ambient seismic noise correlation methods provide constraints at shorter periods and shallower depths. Receiver functions provide precise estimates of crustal structure beneath the stations, and P and S wave tomography provides models of upper mantle structure down to ~ 500 km depth along transects of greater seismic station density. The new seismic results show that the high elevations of the GSM are supported by thick crust (~ 55 km), and are underlain by thick Precambrian continental lithosphere that initially formed during Archean to mid-Proterozoic times. The absence of lithospheric thermal anomalies suggests that the mountains were formed by a compressional orogeny during the Paleozoic, thus providing a locus for ice sheet nucleation throughout a long period of geological time. Within West Antarctica, the crust and lithosphere are extremely thin near the Transantarctic Mountain Front and topographic lows such as the Bentley Trench and Byrd Basin, which represent currently inactive Cenozoic rift systems. Slow seismic velocities beneath Marie Byrd Land at asthenospheric depths suggest a major thermal anomaly, possibly due to a mantle plume. Volcanic earthquakes detected in this region indicate the presence of currently active magma systems. The results suggest large lateral changes in parameters needed for glaciological models, including lithospheric thickness, mantle viscosity, and heat flow. Extremely high heat flow is predicted for much of West Antarctica, consistent with recent results from the WAIS ice drilling. Using the seismic results to estimate mantle viscosity, we find several orders of magnitude difference in viscosity between East and West Antarctica, with lowest viscosities found beneath Marie Byrd Land and the West Antarctic Rift System. Realistic glacial isostatic adjustment models must take these large lateral variations into account.

Wiens, Douglas; Heeszel, David; Sun, Xinlei; Lloyd, Andrew; Nyblade, Andrew; Anandakrishnan, Sridhar; Aster, Richard; Chaput, Julien; Huerta, Audrey; Hansen, Samantha; Wilson, Terry

2013-04-01

185

Microbial ecology of terrestrial Antarctica: Are microbial systems at risk from human activities?  

SciTech Connect

Many of the ecological systems found in continental Antarctica are comprised entirely of microbial species. Concerns have arisen that these microbial systems might be at risk either directly through the actions of humans or indirectly through increased competition from introduced species. Although protection of native biota is covered by the Protocol on Environmental Protection to the Antarctic Treaty, strict measures for preventing the introduction on non-native species or for protecting microbial habitats may be impractical. This report summarizes the research conducted to date on microbial ecosystems in continental Antarctica and discusses the need for protecting these ecosystems. The focus is on communities inhabiting soil and rock surfaces in non-coastal areas of continental Antarctica. Although current polices regarding waste management and other operations in Antarctic research stations serve to reduce the introduction on non- native microbial species, importation cannot be eliminated entirely. Increased awareness of microbial habitats by field personnel and protection of certain unique habitats from physical destruction by humans may be necessary. At present, small-scale impacts from human activities are occurring in certain areas both in terms of introduced species and destruction of habitat. On a large scale, however, it is questionable whether the introduction of non-native microbial species to terrestrial Antarctica merits concern.

White, G.J.

1996-08-01

186

On the Terms of Geomagnetic Daily Variation in Antarctica  

NASA Astrophysics Data System (ADS)

The nature of magnetic perturbations produced by ionospheric and magnetospheric currents recorded in Antarctica, is here investigated. A mathematical method, known as Natural Orthogonal Composition, is applied to analyze the magnetic field disturbances along the three geomagnetic field components (X, Y and Z) measured at Mario Zucchelli Station (IAGA code TNB; geographic coordinates: 74.7°S, 164.1°E) from 1995 to 1998. This type of analysis allows characterizing the dominant modes of the geomagnetic field daily variability through a set of empirical orthogonal functions (EOFs). Even though such mathematically independent EOFs do not necessarily represent physically independent modes of variability, results show that some of them are actually related to well known current patterns located at high latitudes.

Tozzi, R.; de Michelis, P.; Meloni, A.

2009-12-01

187

A Multi-Aperture Scintillation Sensor for Dome A, Antarctica  

NASA Astrophysics Data System (ADS)

Site-testing measurements by the Australian group has already shown that Dome C on the Antarctic plateau is one of the best ground-based astronomical sites. Furthermore, Dome A, the Antarctic Kunlun Station, as the highest point on Antarctic inland plateau, where a Chinese Antarctic scientific expedition team first reached in 2005, is widely predicted to be an even better astronomical site by the international astronomical community. Preliminary site-testing carried out by the Center for Antarctic Astronomy (CAS) also confirms Dome A as a potential astronomical site. Multi-aperture scintillation sensors (MASS) can measure the seeing and isoplantic angle, the turbulence profile, etc., which are very important site-testing parameters that we urgently need. The MASS site testing at Dome A is presented here, and includes the method of processing data and the hardware for the extreme conditions of Dome A, Antarctica.

Chen, Hualin; Pei, Chong; Yuan, Xiangyan

2013-01-01

188

Explosive seismic reflection data from dome Halfarryggen, Antarctica  

NASA Astrophysics Data System (ADS)

Here we present the results from a explosive seismic survey performed in January 2010, at the ice dome Halfarryggen, close to the ice shelf Ekströmisen in East Antarctica. The dome lies 120 km south east of the German research station Neumayer. Two 6 km long perpendicular lines were shot over the dome, large enough to capture the structure of the present Raymond bump. For recording we used a 60 channel 1500 m long snow streamer. To reduce spatial aliasing two shots were combined into one data record. The focus of the seismic survey lies upon the physics that can be extracted from the internal and basal ice reflections. This includes bed conditions, crystal orientation fabric and seismic wave velocities.

Hofstede, Coen

2010-05-01

189

THE BIRDS OF SEYMOUR ISLAND, ANTARCTICA  

Microsoft Academic Search

During January-February 2000, we obtained information on the abundance and distribution of seabirds in Seymour Island, Antarctica. Six species breed in this area: Adélie Penguin (Pygoscelis adeliae; 28,255 pairs), Wilson's Storm-petrel (Oceanites oceanicus; 22), Brown Skua (Catharacta antarctica; 30), South Polar Skua (C. maccormicki; 33), Kelp Gull (Larus dominicanus; 296) and Antarctic Tern (Sterna vittata; 107). In addition, five non-breeding

Diego Montalti; Guillermo E. Soave

190

The hydrological cycle of Greenland and Antarctica  

Microsoft Academic Search

SuhfMARY: The great ice caps of Grccnland and Antarctica hold niost of the 75 Yi of the world's fresh water which is stored as glacier ice. The storagc time is from tens to hundreds of thousand years. Greenland holds about 7.4 million km3 water and Antarctica 30 million kmJ. If it all melted, the sea level would be raised about

Svenn Orvig

191

Galactic bursts signature in Antarctica 10 Be  

Microsoft Academic Search

I detected a very strong (25 %var) period of 3592±57 years at 99% confidence level in the 10 Be deposition rates from Vostok, Antarctica ice-core raw (gapped, unaltered) data. The period was verified at 99% confidence level against the 10Be concentration raw data at both Vostok-as 3700±57 years at very strong 38 %var, and Taylor Dome, Antarctica-as 3800±61 years at

Mensur Omerbashich

192

Putting Antarctica on the Map  

NSDL National Science Digital Library

In this six-day unit, students examine historical maps of Antarctica and research early explorers to gain perspective on how cartography and our understanding of the globe have changed. Throughout the unit, students collect their findings in a portfolio. Teacher tools for this unit include individually downloadable readings, detailed daily breakdowns of tasks, teacher strategies for using the activities, a portfolio grading sheet, a project rubric sheet, and additional readings. Student activities include a Web activity in which students examine and compare historical maps and their modern-day equivalents, focusing on how map-making techniques have changed, a classroom activity in which students examine the history of Antarctic exploration and conduct research on a topic of interest, and several readings that provide a broad perspective. A student handout with guidance for putting together their portfolios and examples of creative final projects is also included.

193

Contamination effects by a ‘conventional’ and a ‘biodegradable’ lubricant oil on infaunal recruitment to Antarctic sediments: A field experiment  

Microsoft Academic Search

To investigate the impacts of synthetic lubricants on Antarctic infaunal communities, a field experiment was setup near Australia's Casey Station, East Antarctica. Two types of synthetic lubricants were tested: an ‘Unused’ and ‘Used’ conventional synthetic lubricant, and an alternative marketed as ‘biodegradable’. Clean defaunated sediment was contaminated with the lubricants, decanted into trays, and deployed by divers onto the seabed

B. A. W. Thompson; P. M. Goldsworthy; M. J. Riddle; I. Snape; J. S. Stark

2007-01-01

194

Degradation of nonane by bacteria from Antarctic marine sediment  

Microsoft Academic Search

A microbial enrichment culture tolerant of petroleum hydrocarbons was developed from sediment collected near Casey Station, Antarctica. To select cold-adapted microbes that would degrade diesel, enrichments were cultured at 0°C during six successive transfers to fresh medium, with Special Antarctic Blend diesel (SAB) as the sole carbon source. Biodegradation of components of the SAB was then measured in microcosms inoculated

S. M. Powell; J. P. Bowman; I. Snape

2004-01-01

195

Seismic Anisotropy Analysis in the Victoria Land Region (Antarctica)  

NASA Astrophysics Data System (ADS)

We present shear-wave splitting results obtained from analysis of core refracted teleseismic phases recorded by permanent and temporary seismographic stations located in the Victoria Land region (Antarctica). We used eigenvalue technique to linearize the rotated and shifted shear-wave particle motion, in order to determine the best splitting parameters. A well-scattered distribution of single shear-wave measurements has been obtained. Average values show clearly that dominant fast axis direction is NE-SW oriented, accordingly with previous measurements obtained around this zone. Only two stations, OHG and STAR show different orientations, with N-S and NNW-SSE main directions. On the basis of the periodicity of single shear-wave splitting measurements with respect to back-azimuths of events under study, we inferred the presence of lateral and vertical changes in the deep anisotropy direction. To test this hypothesis we have modelling waveforms using a cross-convolution technique in one and two anisotropic layer's cases. We obtained a significant improvement on the misfit in the double layer case for the cited couple of stations. For stations where a multi-layer structure does not fit, we looked for evidences of lateral anisotropy changes at depth through Fresnel zone computation. As expected, we find that anisotropy beneath the Transantarctic Mountains (TAM) is considerably different from that beneath the Ross Sea. This feature influences the measurement distribution for the two permanent stations TNV and VNDA. Our results show a dominant NE-SW direction over the entire region, but other anisotropy directions are present and find an interpretation when examined in the context of regional tectonics.

Salimbeni, Simone; Pondrelli, Silvia; Danesi, Stefania; Morelli, Andrea

2010-05-01

196

Geodesy in Antarctica: A pilot study based on the TAMDEF GPS network, Victoria Land, Antarctica  

Microsoft Academic Search

The objective of the research presented in this dissertation is a combination of practical and theoretical problems to investigate unique aspects of GPS (Global Positioning System) geodesy in Antarctica. This is derived from a complete analysis of a GPS network called TAMDEF (Trans Antarctic Mountains Deformation), located in Victoria Land, Antarctica. In order to permit access to the International Terrestrial

Guadalupe Esteban Vazquez Becerra

2009-01-01

197

Central West Antarctica among the most rapidly warming regions on Earth  

NASA Astrophysics Data System (ADS)

There is clear evidence that the West Antarctic Ice Sheet is contributing to sea-level rise. In contrast, West Antarctic temperature changes in recent decades remain uncertain. West Antarctica has probably warmed since the 1950s, but there is disagreement regarding the magnitude, seasonality and spatial extent of this warming. This is primarily because long-term near-surface temperature observations are restricted to Byrd Station in central West Antarctica, a data set with substantial gaps. Here, we present a complete temperature record for Byrd Station, in which observations have been corrected, and gaps have been filled using global reanalysis data and spatial interpolation. The record reveals a linear increase in annual temperature between 1958 and 2010 by 2.4+/-1.2°C, establishing central West Antarctica as one of the fastest-warming regions globally. We confirm previous reports of West Antarctic warming, in annual average and in austral spring and winter, but find substantially larger temperature increases. In contrast to previous studies, we report statistically significant warming during austral summer, particularly in December-January, the peak of the melting season. A continued rise in summer temperatures could lead to more frequent and extensive episodes of surface melting of the West Antarctic Ice Sheet. These results argue for a robust long-term meteorological observation network in the region.

Bromwich, David H.; Nicolas, Julien P.; Monaghan, Andrew J.; Lazzara, Matthew A.; Keller, Linda M.; Weidner, George A.; Wilson, Aaron B.

2013-02-01

198

Stations Outdoors  

ERIC Educational Resources Information Center

Described is a program of outdoor education utilizing activity-oriented learning stations. Described are 13 activities including: a pond study, orienteering, nature crafts, outdoor mathematics, linear distance measurement, and area measurement. (SL)

Madison, John P.; And Others

1976-01-01

199

Accumulation Rate Variability along Norway-US Traverse Route, East Antarctica  

NASA Astrophysics Data System (ADS)

A ~2000 km-long transect of 400 MHz ground-penetrating radar (GPR) data was collected during the 2008-2009 Norway-US scientific traverse between South Pole and Troll Station on the Indian Ocean side of East Antarctica. The GPR profiles extend into the firn-ice transition. Density contrasts give rise to many highly reflective stratigraphic horizons in the firn, which can be traced continuously for several hundreds of kilometers, both near the surface and at depth. Here, the structure of these reflecting horizons is used to examine the depositional environment of the ice sheet. We also assign ages to the GPR horizons using intersecting ice cores, which allow us to quantify spatial and temporal variability in snow accumulation rates in a little known portion of East Antarctica.

Hall, M. L.; Hamilton, G. S.; Arcone, S. A.

2009-12-01

200

Study on solar sources and polar cap absorption events recorded in Antarctica  

NASA Astrophysics Data System (ADS)

Particularly intense events occurred on the Sun in a period around minimum of solar activity during cycle 23. We investigated the characteristics of September 2005 and December 2006 events and the properties of the correlated observations of ionospheric absorption, obtained by a 30 MHz riometer installed at Mario Zucchelli Station (MZS-Antarctica), and of geomagnetic activity recorded at Scott Base (Antarctica). Solar events are studied using the characteristics of CMEs measured with SoHO/LASCO coronagraphs and the temporal evolution of solar energetic protons in different energy ranges measured by GOES 11 spacecraft. Analysing these data, we have determined how these effects are finally observed on the Earth's surface not only in the ionospheric absorption of radio waves and in the intense geomagnetic activity, but also as significant variations of cosmic ray modulation, even at high energies.

Perrone, L.; Parisi, M.; Meloni, A.; Damasso, M.; Galliani, M.

2009-06-01

201

Conerly Carole Casey - \\  

Microsoft Academic Search

In 1999 and 2000, twelve states in northern Nigeria declared Islamic law (Shari'ah) the state criminal law for all Muslims, redefining the boundaries of identity, civility, and criminality. In the city of Kano, the implementation of Shari'ah criminal codes appealed to Muslims from all sectors of society, as a democratic alternative to, and strong critique of, colonialism and the elitism

Conerly Casey

2008-01-01

202

Scott v. Casey.  

PubMed

Claims by federal prison inmates that alleged psychological injuries sustained after they volunteered in the late 1950s to participate in medical experiments on the effects of lysergic acid diethylmide (LSD) were barred by the U.S. District Court, Northern District of Georgia, because they were not filed within two years of the inmates' having learned of their injuries. The evidence showed that by the early 1960s the prisoners possessed the critical facts both that they had suffered injuries from ingestion of the drug and that federal prison authorities had cooperated. Although the complicity of the CIA had only later become known, the statute of limitations ran from the time of first knowledge. PMID:11648210

1983-04-29

203

Antarctica: Scientific Journeys from McMurdo to the Pole.  

ERIC Educational Resources Information Center

|This issue of Exploratorium Magazine focuses on Antarctica. Antarctica has one of the most extreme climates in the world with an untouched environment inviting researchers with great opportunities for study. This issue describes the journey of four Exploratorium staff members to frozen Antarctica. Chapters include: (1) "Life at the Bottom of the…

Brand, Judith, Ed.

2002-01-01

204

Space analogue studies in Antarctica  

NASA Astrophysics Data System (ADS)

Medical research has been carried out on the Australian National Antarctic Research Expeditions (ANARE) for 50 years. As an extension of this program collaborative Australian/United States research on immunology, microbiology, psychology and remote medicine has produced important data and insight on how humans adapt to the stress of extreme isolation, confinement and the harsh environment of Antarctica. An outstanding analogue for the isolation and confinement of space missions (especially planetary outposts), ANARE has been used as an international research platform by Australia and the United States since 1993. Collaborative research has demonstrated a lowered responsiveness of the immune system under the isolation and confinement of Antarctic winter-over; a reduction of almost 50% in T cell proliferation to mltogen phytohaemogglutinin, as well as changes in latent herpesvirus states and the expansion of the polyclonal latent Epstein-Barr virus infected B cell populations. Although no clinically significant disease has been found to result from these immune changes, research is currently assessing the effects of psychological factors on the immune system. This and associated research performed to date and its relevance to both organisations is discussed, and comment made on possible extensions to the program in both medical and other fields.

Lugg, D.; Shepanek, M.

1999-09-01

205

The Landsat Image Mosaic of Antarctica (LIMA): A Cutting-Edge Way for Students and Teachers to Learn about Antarctica  

ERIC Educational Resources Information Center

|By studying Antarctica via satellite and through ground-truthing research, we can learn where the ice is melting and why. The Landsat Image Mosaic of Antarctica (LIMA), a new and cutting-edge way for scientists, researchers, educators, students, and the public to look at Antarctica, supports this research and allows for unprecedented views of our…

Campbell, Brian; Bindschadler, Robert

2009-01-01

206

Weather and mass balance in the ablation zone of the Taylor Glacier, Antarctica  

NASA Astrophysics Data System (ADS)

A simple model that predicts ablation from weather station measurements on the Taylor Glacier, Antarctica is presented along with ablation measurements at about 250 ablation stakes. The model output matches the ablation measurements at the weather station locations. Via extrapolation of the weather station measurements to the rest of the glacier, the model also makes predictions for the rest of the ablation zone. These predictions are compared with measurements of ablation, and errors and uncertainties are discussed. Sublimation is the dominant mass-loss mechanism for the majority of the glacier. In the current climate, melt is important only near the terminus and at the margins of the glacier during the summer. Unlike most Antarctic glaciers, the Taylor Glacier terminates on land so calving does not factor into the mass balance. Further development of this model will allow investigation of the mass balance of the Taylor Glacier in past and future climates.

Bliss, A. K.; Cuffey, K. M.; Kavanaugh, J.; Morse, D.

2005-12-01

207

Geodetic measurements of vertical crustal velocity in West Antarctica and the implications for ice mass balance  

NASA Astrophysics Data System (ADS)

We present preliminary geodetic estimates for vertical bedrock velocity at twelve survey GPS stations in the West Antarctic GPS Network, an additional survey station in the northern Antarctic Peninsula, and eleven continuous GPS stations distributed across the continent. The spatial pattern of these velocities is not consistent with any postglacial rebound (PGR) model known to us. Four leading PGR models appear to be overpredicting uplift rates in the Transantarctic Mountains and West Antarctica and underpredicting them in the peninsula north of 65°. This discrepancy cannot be explained in terms of an elastic response to modern ice loss (except, perhaps, in part of the peninsula). Therefore, our initial geodetic results suggest that most GRACE ice mass rate estimates, which are critically dependent on a PGR correction, are systematically biased and are overpredicting ice loss for the continent as a whole.

Bevis, Michael; Kendrick, Eric; Smalley, Robert; Dalziel, Ian; Caccamise, Dana; Sasgen, Ingo; Helsen, Michiel; Taylor, F. W.; Zhou, Hao; Brown, Abel; Raleigh, David; Willis, Michael; Wilson, Terry; Konfal, Stephanie

2009-10-01

208

Composition and distribution of benthic isopod (Crustacea, Malacostraca) families off the Victoria-Land Coast (Ross Sea, Antarctica)  

Microsoft Academic Search

The benthic fauna off the Victoria-Land-Coast, Ross Sea (Antarctica) was investigated during the 19th Italica expedition in February 2004. Samples were taken along a latitudinal transect from Cape Adare down to Terra Nova Bay at water\\u000a depths ranging from 84 to 515 m. A Rauschert dredge was used at 18 stations to collect epi- and infaunal macrobenthos. 9,494\\u000a specimens of Isopoda

Madhumita Choudhury; Angelika Brandt

2007-01-01

209

What Organisms Live in Antarctica Today?  

NSDL National Science Digital Library

In this weeklong unit, students research how flora and fauna have adapted to thrive in Antarctica, and use their knowledge to create imaginary polar organisms. Throughout the unit, students collect their findings in a portfolio. The comprehensive curriculum materials contain: teacher tools, which include individually downloadable readings, detailed daily breakdowns of tasks, teacher strategies for using the activities, a portfolio grading sheet, a project rubric sheet, and additional readings; a Web activity in which students investigate the living conditions in Antarctica and some of the adaptations its organisms have made; a classroom activity in which students apply what they've learned to create models of imaginary polar creatures; several readings that provide a broad perspective, including excerpts from early explorers' journals and Q&A interviews with scientists working in Antarctica and a student handout with guidance for putting together their portfolios and examples of creative final projects.

210

Live from Antarctica: Then and now  

NASA Astrophysics Data System (ADS)

This real-time educational video series, featuring Camille Jennings from Maryland Public Television, includes information from Antarctic scientists and interactive discussion between the scientists and school children from both Maryland and Hawaii. This is part of a 'Passport to Knowledge Special' series. In this part of the four part Antarctic series, the history of Antarctica from its founding to the present, its mammals, plants, and other life forms are shown and discussed. The importance of Antarctica as a research facility is explained, along with different experiments and research that the facilities there perform.

211

Video podcasts as a long-distance outreach tool: Polar science from Byrd Camp, West Antarctica  

NASA Astrophysics Data System (ADS)

Video Podcasts offer a unique opportunity to actively engage the public in ongoing research projects by revealing faces and stories from field, lab and engineering efforts that often happen behind the scenes. Podcasts thus allow the science community to not only present their accomplishments, but also the where, how and why. Publishing these videos in real time while stationed at remote field camps brings particular challenges to the process. This was the case during the POLNET (Polar Earth Observing Network) field seasons at Byrd Camp, West Antarctica. With no internet connection and limited flights in and out of camp, the team worked to produce a series of Video Podcast field updates that were flown to McMurdo Station and uploaded to a web server off the continent. These videos provided glimpses of living and working on a remote ice sheet while installing GPS and seismic stations. At a time when climate science is under extreme scrutiny, this project offered a tangible and human view of efforts to model how ice masses are changing. In any science education effort, the risk of diluting the science until it is no longer meaningful poses certain challenges. At the same time, going into great depth about the methods and theories using technical vocabulary can immediately turn away an audience that is already inundated with information. These videos represent an attempt to creatively and accurately present scientific concepts in short, digestible segments that bring elements of fun from the unique field setting and personalities of Byrd Camp, West Antarctica.

Berg, M.; Science; Engineering Team Of Polenet Field Seasons 2009-10; 2010-11

2011-12-01

212

Science Nation: Climate Change Likely to Devastate Emperor Penguin Populations in Antarctica  

NSDL National Science Digital Library

A new study indicates melting sea ice, caused by climate change, may soon wreak havoc on one colony of emperor penguins--and that could spell doom for a large swath of the entire species. French scientists have been monitoring the emperor penguin colony around the French research station in Terre Adelie in Antarctica since the 1960s. A study funded in part by the National Science Foundation (NSF) is modeling how the Terre Adelie emperor penguin population will likely respond to melting sea ice associated with climate change.

213

Antarctica: What Shall We Do with It?  

ERIC Educational Resources Information Center

|Describes a role playing exercise in which students act as delegates to a meeting at which they will revise the Antarctic Treaty. Background information is presented about Antarctica, the Antarctic Treaty, and positions of 19 nations with regard to the Treaty. (Author/DB)|

Branson, Margaret S.; Long, Cathryn J.

1977-01-01

214

Read--and Walk--to Antarctica  

ERIC Educational Resources Information Center

|The students at Crestwood Primary School proved that they have what it takes to exercise their bodies and their minds. In an effort to support their teacher's scientific expedition to Antarctica, students from kindergarten to second grade pledged to read books and do physical activity that equated to the 12,900 km (8,000-mile) journey to the…

Harr, Natalie; Doneyko, Kathleen; Lee, Richard E., Jr.

2012-01-01

215

CyberHunt: Head Off to Antarctica.  

ERIC Educational Resources Information Center

|Explains how to take an elementary class on a cyber visit to the continent of Antarctica, the highest, driest, and coldest continent on earth. A student reproducible page presents eight web sites to visit in this quest as well as questions to answer about each site. Answers to the questions are included. (SM)|

Kloza, Brad

2001-01-01

216

Antarctica--the Ultimate Summer Institute.  

ERIC Educational Resources Information Center

|Describes personal experiences of a participant in the National Science Foundation program, Teachers Experiencing Antarctica. Uses the study of the temperature history of Taylor Dome to provide teachers with the experience of research and help other teachers recognize that there are opportunities outside the classroom for personal and…

Van Wey, Nate J.

1995-01-01

217

Charting the bathymetry of Weddell Sea, Antarctica  

Microsoft Academic Search

The Federal Republic of Germany has carried out several marine research expeditions including multibeam surveys by the research vessel Polarstern in the southern Atlantic Ocean. Since the bathymetry of the Weddell Sea, Antarctica, is insufficiently known, the Alfred Wegener Institute for Polar and Marine Research (AWI) is preparing bathymetric maps for this region.One project is the production of the series

Heinrich Hinze

1994-01-01

218

Antarctica: Is It More Than Just Ice?  

ERIC Educational Resources Information Center

|The authors introduced polar science in a fourth-grade classroom by means of 3 hands-on activities that addressed (1) the melting of glaciers and ice, (2) the differences between the North and the South Pole, and (3) the geography and landforms of Antarctica. An assessment 4 months after the original activity showed that students remembered the…

Johnson, Cheryl; Gutierrez, Melida

2009-01-01

219

Which Map's the Best Map for Antarctica?  

NSDL National Science Digital Library

This classroom activity helps students understand the benefits and drawback of globes, Mercator maps, and polar map projections. After closely examining all three, students discuss how we represent a spherical object like the Earth on flat surface. The printable five-page handout includes a series of inquiry-based questions related to the representation of Antarctica on the three types of maps.

220

Crust and upper mantle shear wave structure beneath Antarctica from seismic ambient noise  

NASA Astrophysics Data System (ADS)

The successful deployment and year round operation of the AGAP/GAMSEIS and POLENET/ANET arrays in Antarctica, which include more than 50 broad band seismic stations, has provided an unprecedented opportunity to study detailed structure beneath major previously unsampled regions of the continent. Using about three years of continuous data from these arrays (from late 2007 through 2010), together with data from the previous TAMSEIS array and permanent stations around Antarctica, we acquire empirical Green's functions between all possible pairs of seismographs by cross correlating seismic ambient noise. We then extract Rayleigh wave group and phase velocities from 8 to 60 s, and Love wave velocities from 8 to 35 s. Dispersion maps of each period are determined by tomographic inversion. Finally, SV and SH velocities in the crust and upper mantle are inverted from Rayleigh and Love wave constraints, respectively. Our results show the crust and upper mantle structure beneath both East and West Antarctica with higher resolution than obtained in previous studies. Both SV and SH wave velocities show: 1) At shallow depths (<20km), fast velocities are seen beneath the Gamburtsev Mountains, Transantarctic Mountains (TAM), Marie Byrd Land and Ellsworth Mountains, while slow velocities are seen underneath the West Antarctic rift system (WARS) and Ross Embayment. We interpret this result as indicating thick sedimentary deposits in the WARS and Ross Sea. 2) We also find slow velocities in East Antarctica and fast velocities in West Antarctica at about 20-40 km, which is consistent with the thick/thin crust thickness in these two regions. The transition between the fast and slow velocity is along the Transantarctic Mountains front. 3) Beneath the Gamburtsev Mountains, low crustal velocities extend to about 55 km, which is consistent with Hansen et al's (2010) receiver function study and suggest the mountains are supported by thickened crust. 4) There are pronounced slow upper mantle anomalies within the WARS. Because of different coverage/resolution in Rayleigh and Love waves, we also find that the SV map has clear fast anomalies beneath the Ronne Ice Shelf at intermediate depths (20-50 km), which may indicate thin crust in this region. The SH velocity map indicates thickened crust in the Marie Byrd Land relative to the WARS. We will also explore the interpretation of the SH and SV structures using radial anisotropy.

Sun, X.; Wiens, D. A.; Nyblade, A.; Anandakrishnan, S.; Aster, R. C.; Huerta, A. D.; Wilson, T. J.; Kanao, M.; An, M.

2011-12-01

221

Climatology of Pc 1-2 Waves Observed at High Latitudes in Antarctica: A Progress Report  

NASA Astrophysics Data System (ADS)

An increased occurrence of electromagnetic ion cyclotron (EMIC) waves in Earth's magnetosphere has long been noted during the aftermath of magnetic storms. Such waves, classified as Pc 1-2 waves (0.2 - 5 Hz), have been suggested in many theoretical and some observational studies as a significant loss mechanism for both ring current ions and, via parasitic interactions, radiation belt electrons. We have applied the automated wave analysis technique developed by Bortnik et al. [JGR A04204, 2007] to a large, multi-year suite of data from search coil magnetometers deployed at selected stations in Antarctica. These stations include Halley (L = 4.5), AGO A80 (L = 6.3), AGO A81 (L = 7.7), AGO P2 (L = 8.4), AGO P3 (L = 10.2), and South Pole Station (L = 13.6). Data from South Pole Station were recorded nearly continuously for over a solar cycle. Data from U. S. and British Automated Geophysical Observatories span over one solar cycle, but are not continuous at any given station throughout this period. Beginning with 2006 and 2007 data from Halley, we have at each station noted the mean frequency, amplitude, time, and duration of events. We have also parameterized the occurrence of these events according to UT, Kp, Dst, month, phase of magnetic storms, and phase of the solar cycle.

Murphy, M. T.; Engebretson, M. J.; Posch, J. L.; Lessard, M. R.

2008-05-01

222

Seismic monitoring at Deception Island volcano (Antarctica): Recent advances  

NASA Astrophysics Data System (ADS)

Deception Island (South Shetland Island, Antarctica) is an active volcano with recent eruptions (e.g. 1967, 1969 and 1970). It is also among the Antarctic sites most visited by tourists. Besides, there are currently two scientific bases operating during the austral summers, usually from late November to early March. For these reasons it is necessary to deploy a volcano monitoring system as complete as possible, designed specifically to endure the extreme conditions of the volcanic environment and the Antarctic climate. The Instituto Andaluz de Geofísica of University of Granada, Spain (IAG-UGR) performs seismic monitoring on Deception Island since 1994 during austral summer surveys. The seismicity basically includes volcano-tectonic earthquakes, long-period events and volcanic tremor, among other signals. The level of seismicity is moderate, except for a seismo-volcanic crisis in 1999. The seismic monitoring system has evolved during these years, following the trends of the technological developments and software improvements. Recent advances have been mainly focused on: (1) the improvement of the seismic network introducing broadband stations and 24-bit data acquisition systems; (2) the development of a short-period seismic array, with a 12-channel, 24-bit data acquisition system; (3) the implementation of wireless data transmission from the network stations and also from the seismic array to a recording center, allowing for real-time monitoring; (4) the efficiency of the power supply systems and the monitoring of the battery levels and power consumption; (5) the optimization of data analysis procedures, including database management, automated event recognition tools for the identification and classification of seismo-volcanic signals, and apparent slowness vector estimates using seismic array data; (6) the deployment of permanent seismic stations and the transmission of data during the winter using a satellite connection. A single permanent station is operating at Deception Island since 2008. In the current survey we collaborate with the Spanish Army to add another permanent station that will be able to send to the IAG-UGR seismic information about the activity of the volcano during the winter, using a communications satellite (SPAINSAT). These advances simplify the field work and the data acquisition procedures, and allow us to obtain high-quality seismic data in real-time. These improvements have a very important significance for a better and faster interpretation of the seismo-volcanic activity and assessment of the volcanic hazards at Deception Island volcano.

Carmona, E.; Almendros, J.; Martín, R.; Cortés, G.; Alguacil, G.; Moreno, J.; Martín, B.; Martos, A.; Serrano, I.; Stich, D.; Ibáñez, J. M.

2012-04-01

223

45 CFR 674.4 - Restrictions on collection of meteorites in Antarctica.  

Code of Federal Regulations, 2010 CFR

...Restrictions on collection of meteorites in Antarctica. 674.4 Section 674.4 Public...Restrictions on collection of meteorites in Antarctica. No person may collect meteorites in Antarctica for other than scientific research...

2010-10-01

224

45 CFR 674.4 - Restrictions on collection of meteorites in Antarctica.  

Code of Federal Regulations, 2010 CFR

...Restrictions on collection of meteorites in Antarctica. 674.4 Section 674.4 Public...Restrictions on collection of meteorites in Antarctica. No person may collect meteorites in Antarctica for other than scientific research...

2009-10-01

225

Sky Station  

NSDL National Science Digital Library

While satellites are the current backbone of telecommunications and wireless infrastructure, the company that maintains this Web site envisions a completely new technology. The Stratospheric Telecommunications Service (STS) relies on "lighter-than-air platforms which are held in a geo-stationary position in the stratosphere (approximately 21Km) over a major metropolitan area." The Sky Station company documents much of the STS theory online, as well as maintaining news and information articles about the progress of the system's development. US and international organizations have already reserved some of the radio frequency spectrum for stratospheric platforms, and it seems to have considerable support from important agencies.

1997-01-01

226

Ambient Noise Rayleigh Wave Tomography in Antarctica From the TAMSEIS Array  

NASA Astrophysics Data System (ADS)

We image the crust and uppermost mantle structure of the Transantarctic Mountains and surrounding regions of the Ross Sea and East Antarctica using Rayleigh wave group velocities obtained from the cross- correlation of ambient seismic noise. The data was recorded by the 43 broadband seismographs of the Transantarctic Mountain Seismic Experiment (TAMSEIS) which was the first large scale passive seismic deployment in Antarctica. The stations ran from December 2001 until December 2003, but due to the difficulty of running seismic stations in such extreme conditions we often obtain only 40-100 useful days of data for any station pair. To obtain travel times between station pairs we first normalize the recorded data with a running absolute mean to remove the effect of any earthquakes and then cross-correlate day long segments of the vertical component. Correlelograms from each station pair are then stacked, and then the positive and negative time lags are averaged and filtered at a range of periods between 5 and 29 seconds. Errors for travel times measured from the filtered correlelograms are estimated using a bootstrap technique. We obtain good quality waveforms with high signal to noise ratios for station pairs located on both rock and ice. Group velocity maps are obtained by inverting travel time at each period from all possible station pairs after visual inspection, signal-to-noise ratio, repeatability of measurement, minimum station distance, and number of days correlated have been considered. Each period is inverted separately. At long periods the maps show the fastest velocities in the Ross Sea region, where previous studies show the thinnest crust. At short periods, the fastest velocities lie over the Transantarctic Mountains and the slowest velocities lie over thickly sedimented regions in the Ross Sea. Slow velocities at short periods also appear over the Wilkes Subglacial Basin. A cross section of group velocities along a line of stations striking roughly North-South with 80 km interstation spacing also shows slow velocities in the vicinity of the Wilkes Basin indicating a previously unknown sedimentary basin . Further work will involve inversion of the group velocity maps for shear velocity structure and estimation of sediment thickness.

Pyle, M. L.; Wiens, D. A.; Nyblade, A. A.; Anandakrishnan, S.

2008-12-01

227

GPS-derived Precipitable Water Vapour in Antarctica and validation with radiosoundings  

NASA Astrophysics Data System (ADS)

In Polar regions, the atmospheric precipitable water vapour (PWV) content is approximately one third or less than that present at mid latitudes. On the Antarctic Plateau, it drops down to less than a few mm. As a consequence, the use of GPS data in sensing the atmosphere can be reliably applied only on coastal areas, were the PWV is large enough to exceed the sensitivity of the method. Radio-soundings (RS) are periodically performed at several coastal Antarctic stations, where permanent GPS equipments are also installed. The sites to be analyzed were selected according to the radiosonde equipment: the Vaisala sensors' readings were corrected specifically with ad hoc models. The co-location of GPS and radio-soundings allows us to validate the PWV content with totally independent techniques. In this investigation we present the results of the analysis of continuous long time series of GPS data acquired at Mawson (MAW1), Casey (CAS1), Davis (DAV1), McMurdo (MCM4) and Mario Zucchelli (TNB1) stations over twelve years (1999-2010). Particularly, at each site, the PWV is determined with GPS data and the same parameter derived from the analysis of the radio-sounding is used for validation. The GPS analysis is optimized for Antarctic data, using specific atmospheric models (e.g. the Vienna Mapping Function) and particular care in the data screening and elimination. The ZHD values are extracted from a grid model provided by the TU Wien (http://ggosatm.hg.tuwien.ac.at/DELAY/GRID) and bilienarly interpolated at the site location. At MZS, surface met parameters are available and used to compute the ZHD which is compared with the corresponding grid-derived ZHD series. We find discrepancies and a seasonal signal that straightforwardly impact the PW time series.

Negusini, Monia; Sarti, Pierguido; Tomasi, Claudio; Petkov, Boyan; Capra, Alessandro

2013-04-01

228

Multiple meteoroid impact in Antarctica  

NASA Astrophysics Data System (ADS)

In the late 1950's, geophysical field parties undertaking gravity surveys across Antarctica observed over a large area of Wilkes Land (> 240km across) an exceptionally pronounced negative free air anomaly ((to -158.3 mgal). This area was later interpreted as a possible meteor impact site because the gravity profiles were similar to those of known impact sites (apparent rim structures, circular basins, central peaks or rings), they possessed appropriate aspect ratios (e.g., crater diameter vs crater depth), anomalously steep negative free air gravity anomaly gradients (to 4.71 mgal/km) were characteristic of impact craters and uncharacteristic of solely mantle-related or geologic crustal variations, etc. The condition of the ice covering the anomaly (heavily crevassed), the apparent lack of isostatic compensation with surrounding environs, etc suggested the impact was geologically recent and that perhaps a tektite strewn field was associated with it. The distance from the postulated impact to the Australian strewn field was appropriate as are the ages of the tektites there. This early work has been augmented with the detection of a dominant cluster of negative free air gravity anomalies crossing the continental-oceanic boundary, and the East and West Antarctic structural boundary (i.e., Transantarctic Mountains). These anomalies are coincident with complex subglacial craterform topographic features inferred from radiosounding (to -500m below MSL). The major interior positive free air gravity anomalies are associated with subglacial topographic highs. The elliptical distribution of the negative gravity anomalies resemble known multiple impact distributions (scatter ellipses with the larger anomalies forward and the lesser ones aft). This more recent information favors expanding the original proposal to that of a multiple meteoroid impact. The multiple impact hypotheses would explain aeromagnetic surveys revealing ring-shaped structures in the subglacial rock surface much like those of known impact structures (the magnetic anomalies are unusual in magnitude themselves: amplitudes to 3600nT for sensors at 3.5 km elevation). Deviations from this topography can be attributed to glacial scour. Certainly glacial surging should accompany such an impact. The distribution of the apparent impact structures extends beyond the original discovery and on the basis of negative free air anomalies, into the Wilkes Subglacial Basin to the south, athwart the Transantarctic Mountains and into the Ross Embayment to the east. No multiple impact sites of comparable size on Earth have been reported. The above suggestions have been augmented by recent work on cores taken from the Ross Sea which has revealed the presence of material of high magnetic susceptibility often taken as an indicator of meteor impact and tektites. The age of this material is placed in the Late Pliocene. The oldest ages reported for meteorites collected from the Antarctic Blue Ice is ca. 700,000y.

Weihoupt, J. W.; Rice, A.; van der Hoeven, F.

2006-12-01

229

Antarctica: Signs of the Great Thaw  

NSDL National Science Digital Library

Over the past few years, organizations like National Geographic and the National Academy of Sciences have been offering up interactive features on their websites. Many print newspapers have entered this arena as of late, including the New York Times and the Chicago Tribune. Recently, the Tribune offered up this tremendously interesting and visually engaging portrait of the effects of global warming on and around Antarctica. Visitors can start their travels through the continent by looking at the ways in which the thawing sea ice is taking its toll on the Adelie penguins, and then continue to learn about how scientists are attempting to reconstruct the history of various global climate changes. After that, they can take a 360 degree look around the South Pole and also listen to the voices of people who live and work on Antarctica. Free registration required.

230

Planetary geomorphology field studies: Iceland and Antarctica  

NASA Astrophysics Data System (ADS)

Field studies of terrestrial landforms and the processes that shape them provide new directions to the study of planetary features. These studies, conducted in Iceland and in Antarctica, investigated physical and chemical weathering mechanisms and rates, eolitan processes, mudflow phenomena, drainage development, and catastrophic fluvial and volcanic phenomena. Continuing investigations in Iceland fall in three main catagories: (1) catastrophic floods of the Jokulsa a Fjollum, (2) lahars associated with explosive volcanic eruptions of Askja caldera, and (3) rates of eolian abrasion in cold, volcanic deserts. The ice-free valleys of Antarctica, in particular those in South Victoria Land, have much is common with the surface of Mars. In addition to providing independent support for the application of the Iceland findings to consideration of the martian erosional system, the Antarctic observations also provide analogies to other martian phenomena. For example, a family of sand dunes in Victoria Valley are stabilized by the incorporation of snow as beds.

Malin, M. C.

1984-04-01

231

Snow accumulation and its moisture origin over Dome Argus, Antarctica  

NASA Astrophysics Data System (ADS)

The spatial and temporal variability of snow accumulation near Dome Argus, Antarctica, is assessed using new snow pit and stake measurement data together with existing snow pit, ice core and automatic weather station records. Snow accumulation rate shows large inter-annual variations, but stable multi-decadal levels over the last seven centuries. Spatial variations in snow accumulation within the space of 50 km of Dome Argus are relatively small, probably thanks to the smooth topography. A comparison of theses accumulation observations with ECMWF reanalyses (ERA-40 and ERA-Interim) suggests ECMWF reanalysis captures the seasonal variations, but underestimates the overall snow accumulation at Dome Argus by ~50 %. The moisture sources for precipitation over Dome Argus are examined by means of a Lagrangian moisture source diagnostic, based on the tracing of specific humidity changes along air parcel trajectories, for the period 2000-2004 using operational ECMWF analysis data. Dome Argus mainly receives moisture from the mid-latitude (46 ± 4°S) South Indian Ocean, with a seasonal latitudinal shift of about 6°. Compared to other central East Antarctic deep ice core sites such as Dome F, Dome C, Vostok, and EPICA Dronning Maud Land, Dome Argus has a more southerly moisture origin, probably due to topographic influences on the moisture transport paths. These results have important implications for the interpretation of future ice cores at Dome Argus.

Wang, Yetang; Sodemann, Harald; Hou, Shugui; Masson-Delmotte, Valérie; Jouzel, Jean; Pang, Hongxi

2013-02-01

232

Lecanoric acid, a secondary lichen substance with antioxidant properties from Umbilicaria antarctica in maritime Antarctica (King George Island)  

Microsoft Academic Search

Eight lichen species, Cetraria aculeata, Cladonia furcata, Pseudephebe pubescens, Sphaerophorus globosus, Stereocaulon alpinum, Umbilicaria antarctica, Usnea antarctica and Usnea aurantiacoatra, were collected from King George Island, maritime Antarctica, for the evaluation of antioxidant activities. Anti-linoleic\\u000a acid peroxidation activity, free radical scavenging activity, reducing power and superoxide anion scavenging activity were\\u000a assessed of methanol and acetone extract of the lichens in vitro.

Heng Luo; Yoshikazu Yamamoto; Jung A Kim; Jae Sung Jung; Young Jin Koh; Jae-Seoun Hur

2009-01-01

233

COMNAP:The National Managers in Antarctica  

NASA Astrophysics Data System (ADS)

What is the sole example in human history of unified governance of an entire continent? What is the manifest case of multinational cooperation during the Cold War which affected a large region of the Earth's surface, yet which rarely entered newspaper headlines? For the answer, ask our friends, the penguins; or better yet, read a new book about a remarkable international effort in territorial governance in support of geophysical research and environmental protection, by Captain Alfred N. Fowler, USN (Retired). COMNAP: The National Managers in Antarctica is a personal account of the formation and development of the Council of Managers of National Antarctic Programs (CONMAP), the permanent working group that has operational responsibility and oversight for the many research and other non-profit activities in Antarctica, carried out under the authority of the Antarctic Treaty of 1959. Established in the context of the treaty, CONMAP is the organization responsible for the safe operation and efficient management of national and non-governmental programs of research, environmental monitoring, and other activities performed under the treaty's key provision. This established Antarctica as offlimits to the sovereignty of individual governments, and instead, set aside the entirety of the continent for scientific research and for preservation, with governance to be a cooperative effort among signatory countries. Fowler served as executive secretary of CONMAP from 1988, the year of its formation, to 1997.

Jacobs, Judy; Eastman, Timothy

234

The Ice: A Journey to Antarctica  

NASA Astrophysics Data System (ADS)

The title is misleading for a non—“OAE” (Old Antarctic Explorer, to whom “The Ice” is Antarctica) because The Ice is about far more than just ice. It does indeed cover just about all you'd want to know (or more) about Antarctic ice, from the vast south polar sheets and glaciers to the great tabular bergs, bergy bits, brash ice, pancake ice, frazil ice, and the pack of the polar seas; but it also explores nearly every aspect of this “Last of Lands” in an unusually comprehensive coverage. From the “Heroic Ages” of early 20th-century explorers Robert Scott, Ernest Shackleton, and Roald Amundsen to the present “Cruise Ship Age,”Antarctica has produced a wealth of literature in the “Journey to…” style — which Pyne's is not. Instead, his product from one short (3-month) visit under a National Endowment for the Humanities fellowship takes all readers o n a webwork journey through time, space, ice, and rocks for an appreciation of “ The Ice” in a way found in no other book. This, his fifth book (another one is Fire in America, Princeton University Press, Princeton, N.J., 1982), is a significant contribution to the literature of Antarctica. Pyne's prose cannot be paraphrased for a review, as the reader will be able to appreciate from the excerpts to follow.

Ford, Arthur B.

235

Site testing Dome A, Antarctica  

NASA Astrophysics Data System (ADS)

Recent data have shown that Dome C, on the Antarctic plateau, is an exceptional site for astronomy, with atmospheric conditions superior to those at any existing mid-latitude site. Dome C, however, may not be the best site on the Antarctic plateau for every kind of astronomy. The highest point of the plateau is Dome A, some 800 m higher than Dome C. It should experience colder atmospheric temperatures, lower wind speeds, and a turbulent boundary layer that is confined closer to the ground. The Dome A site was first visited in January 2005 via an overland traverse, conducted by the Polar Research Institute of China. The PRIC plans to return to the site to establish a permanently manned station within the next decade. The University of New South Wales, in collaboration with a number of international institutions, is currently developing a remote automated site testing observatory for deployment to Dome A in the 2007/8 austral summer as part of the International Polar Year. This self-powered observatory will be equipped with a suite of site testing instruments measuring turbulence, optical and infrared sky background, and sub-millimetre transparency. We present here a discussion of the objectives of the site testing campaign and the planned configuration of the observatory.

Lawrence, J. S.; Ashley, M. C. B.; Burton, M. G.; Cui, X.; Everett, J. R.; Indermuehle, B. T.; Kenyon, S. L.; Luong-Van, D.; Moore, A. M.; Storey, J. W. V.; Tokovinin, A.; Travouillon, T.; Pennypacker, C.; Wang, L.; York, D.

2006-07-01

236

Auroral images and particle precipitations observed by S-310JA-8, -9, and -10 at Syowa Station  

Microsoft Academic Search

Three sounding rockets launched in 1984 from Syowa Station, Antarctica, into different types of aurora obtained auroral pictures and measured the energy spectra of auroral particles. The active auroral arc at the substorm expansion phase displayed greater values of auroral emission and electron density than the stable arc prior to the substorm onset. The diffuse aurora during the recovery stage

Masaki Ejiri; Takayuki Ono; Takeo Hirasawa; Takasi Oguti

1988-01-01

237

Explorer 45 and Imp 6 Observations in the Magnetosphere of Injected Waves from the Siple Station VLF Transmitter  

Microsoft Academic Search

This paper reports the first results of a Stanford University-University of Iowa joint experiment in which VLF waves from the Siple Station transmitter in Antarctica are injected into the maghetosphere along the earth's magnetic field lines and are detected near the magnetic equatorial plane by the Explorer 45 and Imp 6 spacecraft. The purpose of this experiment is to conduct

T. F. Bell; D. L. Carpenter; R. R. Anderson

1977-01-01

238

Iron Meteorites from Antarctica: More Specimens, Still 40% Ungrouped.  

National Technical Information Service (NTIS)

Clarke was the first to recognize that ungrouped irons are more common in Antarctica than in the regions where most irons have been collected; his conclusion was based on the first 21 irons collected in Antarctica. Wasson et al. reported compositional dat...

J. T. Wasson

1999-01-01

239

Ungrouped iron meteorites in Antarctica - Origin of anomalously high abundance  

Microsoft Academic Search

Eighty-five percent of the iron meteorites collected outside Antarctica are assigned to 13 compositionally and structurally defined groups; the remaining 15 percent are ungrouped. Of the 31 iron meteorites recovered from Antarctica, 39 percent are ungrouped. This major difference in the two sets is almost certainly not a stochastic variation, a latitudinal effect, or an effect associated with differences in

John T. Wasson

1990-01-01

240

The global historical climatology network: Long-term monthly temperature, precipitation, sea level pressure, and station pressure data  

SciTech Connect

This NDP contains monthly temperature, precipitation, sea level pressure, and station pressure data for thousands of meteorological stations worldwide. The database was compiled from pre-existing national, regional, and global collections of data as a part of the Global Historical Climatology Network (CHCN) project. It contains data from roughly 6000 temperature stations, 7500 precipitation stations, 1800 sea level pressure stations, and 1800 station pressure stations. Each station has at least 10 years of data, and about 40% have more than 50 years of data. Spatial coverage is good over most of the globe, particularly for the United States and Europe. Data gaps are evident over the Amazon rainforest, the Sahara desert, Greenland, and Antarctica.

Vose, R.S.; Schmoyer, R.L. [Oak Ridge National Lab., TN (United States); Steurer, P.M.; Peterson, T.C. [National Climatic Data Center, Asheville, NC (United States)] [and others

1992-12-31

241

Space Station Live: Station Communications Upgrade  

NASA Video Gallery

NASA Public Affairs Officer Nicole Cloutier-Lemasters recently spoke with Penny Roberts, one of the leads for the International Space Station Avionics and Software group, about the upgrade of the Ku-band communications gear aboard the station.

Gerald T Wright

2013-04-12

242

Records of climatic changes and volcanic events in an ice core from Central Dronning Maud Land (East Antarctica) during the past century  

Microsoft Academic Search

The depth profiles of electrical conductance, ?18O,210Pb and cosmogenic radio isotopes10Be and36Cl have been measured in a 30 m ice core from east Antarctica near the Indian station, Dakshin Gangotri. Using210Pb and ?18O, the mean annual accumulation rates have been calculated to be 20 and 21 cm of ice equivalent per year during the past ?\\u000a 150 years. Using these

V. N. Nijampurkar; D. K. Rao; H. B. Clausen; M. K. Kaul; A. Chaturvedi

2002-01-01

243

Records of climatic changes and volcanic events in an ice core from Central Dronning Maud Land (East Antarctica) during the past century  

Microsoft Academic Search

The depth profiles of electrical conductance, delta18O,210Pb and cosmogenic radio isotopes10Be and36Cl have been measured in a 30 m ice core from east Antarctica near the Indian station, Dakshin Gangotri. Using210Pb and delta18O, the mean annual accumulation rates have been calculated to be 20 and 21 cm of ice equivalent per year during the past ˜ 150 years. Using these

V. N. Nijampurkar; D. K. Rao; H. B. Clausen; M. K. Kaul; A. Chaturvedi

2002-01-01

244

Shear-wave velocity structure of Antarctica from Rayleigh-wave analysis  

NASA Astrophysics Data System (ADS)

The elastic structure beneath Antarctica is shown by means of S-velocity maps for depths ranging from zero to 400 km, determined by the regionalization and inversion of Rayleigh-wave dispersion. The traces of 93 earthquakes, occurring from 1990 to 2011, have been used to obtain Rayleigh-wave dispersion data. These earthquakes were registered by 30 seismic stations located in Antarctica. The dispersion curves were obtained for periods between 5 and 250 s, by digital filtering with a combination of MFT and TVF filtering techniques. Later, all seismic events (and some stations) were grouped to obtain a dispersion curve for each source-station path. These dispersion curves were regionalized and inverted according to the generalized inversion theory, to obtain shear-wave velocity models for a rectangular grid of 20 × 20 points. The shear-velocity structure obtained through this procedure is shown in the S-velocity maps plotted for several depths. These results agree well with the geology and other geophysical results previously obtained. The obtained S-velocity models suggest the existence of lateral and vertical heterogeneities. The zones with consolidated and old structures present greater S-velocity values than the other zones, although this difference can be very little or negligible in some case. Nevertheless, in the depth range of 10 to 45 km, the different Moho depths present in the study area generate the principal variation of S-velocity. A similar behaviour is found for the depth range from 80 to 230 km, in which the lithosphere-asthenosphere boundary generates the principal variations of S-velocity. Finally, a new and interesting feature obtained in this study should be highlighted: the definition of the LAB and the base of the asthenosphere (for the whole study area), for depths ranging from 80 to 230 km and from 180 to 280 km, respectively.

Corchete, V.

2013-01-01

245

Putting Antarctica on the Map: Understanding Exploration  

NSDL National Science Digital Library

In this activity, students will consider the compass, dog sled, telephone, computer, Global Positioning System (GPS) and try to decide which of these technological advances has made the biggest contribution to Antarctic exploration. The activity, which is structured as a series of mini-research projects, helps students understand how technological advances have aided the exploration of Antarctica. The printable five-page handout includes a series of inquiry-based questions to introduce the topic of Antarctic exploration, a set of research topics that can be assigned to small student teams, and detailed directions for the activity. Worksheets are also provided to help students compile their research findings.

246

The Exploration of the ISM from Antarctica  

NASA Astrophysics Data System (ADS)

Antarctica presents a unique environment for the exploration of the interstellar medium. The low column of water vapor opens windows for sub-mm and THz astronomy from ground and sub-orbital observatories while the stable atmosphere holds promise for THz interferometry. Various current and potentially future facilities occupy a niche not available to current space or stratospheric instruments. These allow line and continuum observations addressing key questions in e.g., star formation, galactic evolution, and the life-cycle of interstellar clouds. This review presents scientific questions that can be addressed by the suite of current and future Antarctic observatories.

Wolfire, Mark G.

2013-01-01

247

Trace metals in Antarctica related to climate change and increasing human impact.  

PubMed

Metals are natural constituents of the abiotic and biotic components of all ecosystems, and under natural conditions they are cycled within and between the geochemical spheres--the atmosphere, lithosphere, hydrosphere, and biosphere--at quite steady fluxes. In the second half of the twentieth century, the huge increase in energy and mineral consumption determined anthropogenic emissions of several metals exceeding those from natural sources, e.g., volcanoes and windborne soil particles. In the Northern Hemisphere, the biogeochemical cycles of Pb, Cd, Zn, Cu, and other metals were significantly altered, even in Arctic regions. On the contrary, available data on trace metal concentrations in abiotic matrices from continental Antarctica, summarized in this review, suggest that the biogeochemical cycle of Pb is probably the only one that has been significantly altered by anthropogenic emissions in Antarctica and elsewhere in the Southern Hemisphere, especially in the period 1950-1975. Environmental contamination by other metals from anthropogenic sources in Antarctica itself can generally only be detected in snow samples taken within a range of a few kilometers or several hundred meters from scientific stations. Local metal pollution from human activities in Antarctica may compromise studies aimed at assessing the biogeochemical cycle of trace elements and the effects of global climate change. Thus, this review focuses on concentrations of metals in atmospheric particulate, snow, surface soils, and freshwater from the Antarctic continent and surface sediments and seawater from the Southern Ocean, which can plausibly be regarded as global background values of trace elements. These baselines are also necessary in view of the construction of new stations, the expansion of existing facilities to support research, and the growth of tourism and fisheries. Despite difficulties in making comparisons with data from other remote areas of the world, concentrations of trace metals in most samples of atmospheric particulates, snow, ice, soils, and marine sediments from Antarctica can be taken as global background levels. Comparison between the results of trace element surveys in marine waters of the Southern Ocean and in other seas is practically impossible. The upwelling or subduction of water masses, the seasonality in ice cover and in phytoplankton biomass, the low fallout of atmospheric dust, and many other peculiar characteristics of the Southern Ocean make concentrations of trace metals in surface waters quite variable in space and time. The depletion of nutrients in surface waters, which is a regular feature of many marine environments, rarely occurs in the Southern Ocean. Waters in some regions are characterized by very low concentrations of Fe and Mn, whereas in others the content of Cd is relatively high at the beginning of summer and may decrease about one order of magnitude during the phytoplankton bloom. Although in most Antarctic coastal ecosystems the input of metals from geochemical and anthropogenic sources and from long-range transport is negligible, concentrations of Cd in the waters and biota may be higher than in waters and related species of organisms from polluted coastal areas. Like the Southern Ocean, Antarctic lakes have many peculiar characteristics. They are often perennially ice covered and without outlet, and their water, which is gained only from short-term melting of snow and glaciers in summer, is lost mainly by sublimation of surface ice. Several lakes are distinctly stratified: the water under the ice may be cool, rich in oxygen, and among the cleanest and clearest of natural waters, whereas water near the bottom becomes anoxic, tepid, and richer in major and trace elements. Considering the specificity of Antarctic environments, to evaluate the extent and consequences of global changes and increasing human activities in Antarctica itself, research on the biogeochemistry of trace metals and monitoring programs PMID:10868078

Bargagli, R

2000-01-01

248

Development of an Automatic Blowing Snow station  

NASA Astrophysics Data System (ADS)

On the Antarctic ice sheet, strong katabatic winds blow throughout the year and a large but unknown fraction of the snow which falls on it is removed continuously. This constitutes a significant factor in mass and energy balance and is all the more important when predicting the likely effects of global climate change. Further, recent experimental work has indicated that the snowdrift sublimation can lead to significant mass losses during strong winds and can be also an important factor in the surface mass balance of the Antarctic ice sheets. Nishimura and Nemoto (2005) carried out the blowing snow observations at Mizuho station, Antarctica in 2000 with the snow particle counters (SPC) that can sense not only the number of snow particles but also their diameters. SPC worked properly and the data obtained revealed profiles of mass flux and particle size distributions as a function of the friction velocity. However, the SPC requires rather high power supply and the data is stored in PC; it is not always suitable for the unmanned observations under the severe Antarctic conditions. Thus, we have developed a simpler device by measuring the attenuation of the light intensity, which strongly depends on the blowing snow flux. A small wind turbine and a cold-proof buttery were utilized as a power source. Firstly, its performance was tested with comparing the SPC in a cold wind tunnel system and it proved adequately fit for practical use by combining the output of the anemometer. In 2009/2010 winter, three systems have been set at Ishikari, Col du Lac blanc in France, and S17 near Syowa station in Antarctica, and the tests are still continuing.

Nishimura, K.

2010-12-01

249

Plans for direct measurement and sampling of Subglacial Lake Ellsworth, West Antarctica  

NASA Astrophysics Data System (ADS)

The Lake Ellsworth programme has two fundamental scientific aims: (1) to determine whether, and in what form, microbial life exists in Antarctic subglacial lakes, and (2) to reveal the post-Pliocene history of the West Antarctic Ice Sheet. To meet these aims, we will undertake the direct measurement and sampling of water and sediment within Subglacial Lake Ellsworth in West Antarctica. For over a decade, scientists have regarded subglacial lakes to be extreme yet viable habitats for microbial life. Additionally, sedimentary palaeoenvironment records are thought to exist on the floors of subglacial lakes, which would provide critical insights into the glacial history of Antarctica. Of the >150 known subglacial lakes, Lake Ellsworth stands out as an ideal candidate for exploration. Glaciologists have shown the lake, beneath 3 km of ice, to be 10 km long, 2.5 km wide and 160 m deep, confirming it as an ideal deep-water lake for exploration. The deployment of heavy equipment has been shown to be possible at this location, based on several deep-field reconnaissance studies. This project will build, test and deploy all the equipment necessary to complete the experiment in a clean and environmentally responsible manner. Samples will be analysed and split in field laboratories and at Rothera Station, and then distributed to laboratories across the UK. This project, which has been in a planning stage for four years, will be a benchmark exercise in the exploration of Antarctica, and could make profound scientific discoveries regarding life in extreme environments and West Antarctic Ice Sheet history.

Siegert, M. J.

2009-12-01

250

Sources of Sea Salts to Coastal Antarctica  

NASA Astrophysics Data System (ADS)

Coastal Antarctic sea salt aerosols are partitioned into two main sources, namely ocean sea spray and surface sea ice. The sea spray source is related to windiness over the surface ocean and the action of bubbles bursting. The sea ice source is due to frost flowers which form on the surface of sea ice, which are concentrated in sea salts and are lofted by wind action over the sea ice zone. At high accumulation coastal sites, with seasonal resolution, it is possible to estimate the sources of both using deviations of the sodium to sulphate ratio from that found in seawater. To date, from ice core records in east Antarctica (including iceberg B09B near the Mertz Glacier, Law Dome, Wilkes Land and Wilhelm II land), we have found that the source strength from surface sea ice to the Antarctic ice sheet diminishes with elevation and distance inland. We present new data from coastal ice core sites including Mill Island off the coast of east Antarctica and the upper and lower Totten glacier to the east of Law Dome. Using this combined dataset we estimate the source strengths of sea salt aerosols, their partitioning and quantify the relationship with elevation and distance inland.

Curran, M. A.; van Ommen, T. D.; Moy, A. D.; Vance, T.; Wong, G. J.; Goodwin, I. D.; Domensino, B.

2010-12-01

251

Cenozoic motion between East and West Antarctica  

PubMed

The West Antarctic rift system is the result of late Mesozoic and Cenozoic extension between East and West Antarctica, and represents one of the largest active continental rift systems on Earth. But the timing and magnitude of the plate motions leading to the development of this rift system remain poorly known, because of a lack of magnetic anomaly and fracture zone constraints on seafloor spreading. Here we report on magnetic data, gravity data and swath bathymetry collected in several areas of the south Tasman Sea and northern Ross Sea. These results enable us to calculate mid-Cenozoic rotation parameters for East and West Antarctica. These rotations show that there was roughly 180 km of separation in the western Ross Sea embayment in Eocene and Oligocene time. This episode of extension provides a tectonic setting for several significant Cenozoic tectonic events in the Ross Sea embayment including the uplift of the Transantarctic Mountains and the deposition of large thicknesses of Oligocene sediments. Inclusion of this East-West Antarctic motion in the plate circuit linking the Australia, Antarctic and Pacific plates removes a puzzling gap between the Lord Howe rise and Campbell plateau found in previous early Tertiary reconstructions of the New Zealand region. Determination of this East-West Antarctic motion also resolves a long standing controversy regarding the contribution of deformation in this region to the global plate circuit linking the Pacific to the rest of the world. PMID:10724159

Cande; Stock; Muller; Ishihara

2000-03-01

252

Crustal Vp-Vs ratios and thickness for Ross Island and the Transantarctic Mountain front, Antarctica  

NASA Astrophysics Data System (ADS)

We investigate crustal Vp-Vs ratios and thickness along the Transantarctic Mountain (TAM) front and on Ross Island, Antarctica to determine if the TAM crust has been modified by the Neogene magmatism associated with Ross Island. A seismic low velocity zone (LVZ) in the upper mantle beneath Ross Island extends laterally ˜80 km under the TAM front, and mantle temperatures within the LVZ may be sufficiently elevated for partial melting to have occurred and modified the crust. Data for the study come from 16 temporary seismic stations that were part of the TAM Seismic Experiment and three permanent stations. Estimates of Vp/Vs (?) and crustal thickness (H) have been obtained from receiver functions analysed using the H-? stacking method for 10 of the stations, and for the remaining stations, crustal thickness has been calculated by using the Moho Ps arrival time with an assumed Vp/Vs value. A Vp/Vs value of 1.88 is obtained for Ross Island, consistent with the mafic composition of the volcanic rocks from Mt. Erebus. Vp/Vs values for stations in the TAM situated away from the LVZ range from 1.63 to 1.78, with a mean of 1.73, while values for stations in the TAM lying above the LVZ range from 1.67 to 1.78, with a mean of 1.72. This result indicates that there is little difference in bulk crustal composition for areas above and away from the LVZ, and together with a Vp/Vs value (1.73) that is typical for felsic to intermediate composition crust, suggests that the crust along the TAM front has not been altered significantly by mafic magmatism. Crustal thickness estimates along the coast are quite variable, ranging from 18 to 33 km, and increase to 39 km inland beneath the crest of the TAM. On Ross Island, crustal thickness estimates range between 19 and 27 km.

Finotello, Marco; Nyblade, Andrew; Julia, Jordi; Wiens, Douglas; Anandakrishnan, Sridhar

2011-04-01

253

Long term changes in the upper stratospheric ozone at Syowa, Antarctica  

NASA Astrophysics Data System (ADS)

Analyses of stratospheric ozone data determined from Dobson Umkehr measurements since 1977 at the Syowa (69.0° S, 39.6° E), Antarctica station show a significant decrease in ozone at altitudes higher than that of the 4 hPa pressure level during the 1980s and 1990s. Ozone values over Syowa have remained low since 2001. The time series of upper stratospheric ozone from the homogenized NOAA (/2) SBUV 8.6 overpass data (± 4°, 24 h) are in qualitative agreement with Syowa station data. Ozone recovery during the austral spring over Syowa station appears to be slower than predicted by the Equivalent Effective Stratospheric Chlorine (EESC) curve. The long-term changes in station's equivalent latitude are derived from MERRA analysis at ~2 hPa and ~50 hPa. These data are used to attribute some of the upper and middle stratospheric ozone changes to the changes in vortex position relative to station location. In addition, high correlation of the Southern Hemisphere Annular Mode (SAM) with polar upper stratospheric ozone during years of maximum solar activity points toward a strong relationship between the strength of the Brewer-Dobson circulation and the polar stratospheric ozone recovery. We have analyzed the results of ozone profiles over Syowa determined from measurements of the Umkehr effect by Dobson ozone spectrophotometers. The ozone depletion attributable to CFCs is clearly visible in the record, but the recovery is slower than predicted. Further research indicates that dynamical and other chemical changes in the atmosphere are delaying the recovery over this station.

Miyagawa, K.; Petropavlovskikh, I.; Evans, R. D.; Long, C.; Wild, J.; Manney, G. L.; Daffer, W. H.

2013-01-01

254

OH and RO2 radicals at Dome C (East Antarctica): first observations and assessment of photochemical budget  

NASA Astrophysics Data System (ADS)

Measurements of OH and total peroxy RO2 (HO2 + organic peroxy) radicals were performed in December 2011/January 2012 at the Dome C Concordia station (East Antarctica, 75.1° S / 123.3° E) in the frame of the Oxidant Production over Antarctic Land and its Export (OPALE) project. The goal of these first on the East Antarctica plateau radical measurements was to estimate the oxidative capacity and assess the role of snow emissions on the radical budget in this part of Antarctica. The OH concentration levels were found to be in general similar to those observed at South Pole. However, based on the analysis of the OH sources and sinks derived from the available measurements of NOx, HONO, HCHO, H2O2 and others, it has been concluded that, in contrast to South Pole, the photolysis of HONO is the major OH source at Dome C site. The role of HONO as the major source of OH is also supported by an excellent correlation of OH with the production rate of OH from the HONO photolysis. The observed diurnal profiles of OH and RO2 are discussed in relation with boundary dynamics and the variability of photolysis and snow emissions rates.

Kukui, Alexandre; Loisil, Rodrigue; Kerbrat, Michael; Frey, Markus; Gil Roca, Jaime; Jourdain, Bruno; Ancellet, Gérard; Bekki, Slimane; Legrand, Michel; Preunkert, Susanne

2013-04-01

255

Stratosphere over Dumont d'Urville, Antarctica, in winter 1992  

NASA Astrophysics Data System (ADS)

We present an analysis of the temporal evolution of stratospheric constituents above the station of Dumont d'Urville in Antarctica (67°S, 140°E) from August 14 to September 20, 1992. Data sets include temperature profiles and H2O, ClO, O3, NO2, ClONO2, HNO3, N2O, and CH4 mixing ratios and aerosol extinction coefficients from 46 to 1 hPa measured by the Microwave Limb Sounder (MLS) and the Cryogenic Limb Array Etalon Spectrometer (CLAES) instruments aboard the Upper Atmosphere Research Satellite (UARS). At the station, aerosol extinction coefficients and O3 profiles are obtained by a lidar together with O3 profiles provided by sondes. Integrated O3 and NO2 column amounts are given by a Système d'Analyse par Observation Zénithale (SAOZ) spectrometer located at the station. Column O3 is also provided by the Total Ozone Mapping Spectrometer (TOMS) instrument aboard the NIMBUS 7 satellite, complemented with potential vorticity derived from the U.K. Meteorological Office assimilated data set and temperature fields provided by the European Centre for Medium-Range Weather Forecasts. Time evolution of these measurements is interpreted by comparison with results from the SLIMCAT three-dimensional chemical transport model. We show that the site is near the vortex edge on average and is alternately inside the vortex or just outside in the region referred to as the "collar" region. There are no observations of polar stratospheric clouds (PSCs) over the station above 46 hPa (˜18 km). In fact, PSCs mainly appear over the Palmer Peninsula area at 46 hPa. The rates of change of chemical species are evaluated at 46 hPa when the station is conservatively inside the vortex collar region. The ozone loss rate is 0.04 ppmv d-1 (˜1.3% d-1), which is consistent with other analyses of southern vortex ozone loss rates; chlorine monoxide tends to decrease by 0.03 ppbv d-1, while chlorine nitrate increases by 0.025 ppbv d-1. These negative ClO and positive ClONO2 trends are only observed in the collar region of the vortex where O3 amounts are far from near zero, and little denitrification is observed. Loss and production rates as measured by UARS are more pronounced than the ones deduced from the SLIMCAT model, probably because of the moderate model horizontal resolution (3.75° × 3.75°), which is not high enough to resolve the vortex crossings above Dumont d'Urville and which leads to a larger extent of denitrified air than indicated by the UARS data. The analysis also shows activated ClO inside the vortex at 46 hPa, a dehydrated vortex at 46 hPa, and rehydrated above, with no trace of denitrification in the lower stratosphere. Good agreement between coincident measurements of O3 profiles by UARS/MLS, lidar, and sondes is also observed. Finally, the agreement between UARS and SLIMCAT data sets is much better in the middle stratosphere (4.6 hPa) than in the lower stratosphere (46 hPa).

Ricaud, P.; Monnier, E.; Goutail, F.; Pommereau, J.-P.; David, C.; Godin, S.; Froidevaux, L.; Waters, J. W.; Mergenthaler, J.; Roche, A. E.; Pumphrey, H.; Chipperfield, M. P.

1998-06-01

256

Study of Schumann resonances based on magnetotelluric records from the western Mediterranean and Antarctica  

NASA Astrophysics Data System (ADS)

Eight independent magnetotelluric (MT) campaigns, carried out in the western Mediterranean area and Antarctica, have been analyzed with the aim of extracting information from Schumann resonances (SR). The advantages and drawbacks of MT data with respect to single-purpose fixed stations for SR research are evaluated. Two different methods of signal processing have been employed: spectral analysis through the fast Fourier transform (FFT) and Rescaled Range analysis (R/S), calculating the Hurst exponents. The first permitted a study of the source contributions, the effects caused by local changes in the observation area, interseasonal behavior, and the relations between electric and magnetic horizontal fields. The average central frequencies obtained for the first three resonances are 7.8, 14, and 20.5 Hz respectively, but there are fluctuations in them. These variations seem to respond to the characteristics of the principal active storms that generate the resonances. These frequency shifts are stronger for the second and third resonances. Owing to the broadband registering of MT, the second method of signal processing could be applied to the low noise signals from Antarctica with high resolution, revealing the persistent nature of SR. A numerical simulation indicates a way for inferring lightning rates from R/S analysis.

Toledo-Redondo, S.; Salinas, A.; Portí, J.; Morente, J. A.; Fornieles, J.; MéNdez, A.; Galindo-ZaldíVar, J.; Pedrera, A.; Ruiz-ConstáN, A.; Anahnah, F.

2010-11-01

257

High resolution 900 yr volcanic and climatic record from the Vostok area, East Antarctica  

NASA Astrophysics Data System (ADS)

Detailed volcanic record of the last 900 yr (1093-2010 AD) has been received using high resolution (2-3 samples per accumulation year) sulfate measurements in four snow/firn cores from the Vostok station area, East Antarctica. Totally, 33 volcanic events have been identified in the record, including well-known low latitude eruption signals found in many polar ice cores (e.g., Pinatubo 1991, Agung 1963, Krakatoa 1883, Tambora 1815, Huanaputina 1600, Kuwae 1452), however in comparison with other Antarctic sites the record has more events covering the last 900 yr. The strongest volcanic signals occurred during mid-13th, mid-15th and 18th centuries. The largest volcanic signal of Vostok (both in sulfate concentration and flux) is the 1452 AD Kuwae eruption. Average snow accumulation rate calculated for the period 1093-2010 AD is 21.3 ± 2.3 mm H2O. Accumulation record demonstrates a slight positive trend, however sharply increased accumulation rate during the periods from 1600 to 1815 AD (by 11% from long-term mean) and from 1963 to 2010 AD (by 15%) are typical features of the site. Na+ record shows strong decadal-scale variability probably connected with coupled changes in atmospheric transport patterns over Antarctica (meridional circulation change) and local glaciology. The obtained high resolution climatic records suggest a high sensitivity of the Vostok location to environmental changes in Southern Hemisphere.

Osipov, E. Yu.; Khodzher, T. V.; Golobokova, L. P.; Onischuk, N. A.; Lipenkov, V. Ya.; Ekaykin, A. A.; Osipova, O. P.

2013-05-01

258

Preliminary data analysis from the IPY autonomous surface ozone monitoring network in Dronning Maud Land, Antarctica  

NASA Astrophysics Data System (ADS)

In sharp contrast with stratospheric ozone, the detailed climatology of tropospheric ozone over Antarctica is relatively understudied, partly due the difficulty in establishing long-term measurements in this remote part of our World. The scarcity of year-round surface ozone data is closely tied to that of manned research stations, often confined to coastal Antarctica, with the exception of the South Pole and more recent Concordia continental stations on the East Antarctic Plateau. Current long-term datasets (eg South Pole, Neumayer, Sanae, Halley) reveal similar annual seasonal behaviour: ~30 ppbv winter maximum, and 10-15 ppbv summer minimum. Coastal stations also show well-recognised Ozone Depletion Events (ODE), phenomena which have been observed both in Arctic and Antarctic regions, when near-zero ozone concentrations are measured during the springtime polar sunrise; this ozone loss process is believed to involve rapid photo-catalytic chemistry of Bromine/Iodine species on aerosols and/or frost flowers over open sea-ice leads. The ozone monitoring network presented in this study was proposed as part of the International Polar Year (IPY) to fill in the gap in our knowledge of the regional and climatological extent of ODE, and to probe the snow pack photochemistry impact on the overlying boundary layer oxidative capacity over the Antarctic Plateau. Between December 2007 and January 2009, a network of ten low-powered autonomous surface ozone monitors was deployed along the Weddell Sea coast and up the Dronning Maud Land (DML) plateau. The study region covers ~800km of the South-eastern Weddell Sea coastline. Four sites were located on ice shelves to study the effect of long fetched ODE. Other sites were deployed on a transect between the ice shelf bound coastal zone and up to 2400 m altitude on the DML Plateau, towards the Kohnen station operated by the Alfred Wegener Institute. This North-to-South transect roughly follows the Stancombe-Wills ice stream, an area of katabatic flow funnelling. It should allow us to gauge the effect of Antarctic Eastern Plateau outflow and the impact of (eg NOx) emissions from the continental snow pack on in-situ surface ozone production, in an area removed from ozone depleting oceanic halogen precursors. We present preliminary data from the network, and put it in the context of existing long term surface ozone measurements carried out from manned monitoring stations in the DML region.

Bauguitte, S. J.-B.; Jones, A. E.; Hutterli, M. A.; Anderson, P. S.; Maxfield, D. J.; Roscoe, H. K.; Wolff, E. W.; Virkkula, A.; Kirkwood, S.; Weller, R.

2009-04-01

259

GPS water vapour estimation using meteorological data from Chinese Antarctic research stations  

Microsoft Academic Search

This paper mainly discusses the research deducing atmospheric Precipitable Water Vapor (PWV) from tropospheric zenith wet delay using ground-based GPS receivers. China GreatWall and ZhongShan stations in Antarctica were taken as the researching sites. The data from SCAR Antarctic GPS Campaigns Epoch 1998\\/1999\\/2000 are used to construct the GPS analytical networks. A high-accuracy GPS processing software package-GAMIT\\/GLOBK is utilized; Multiple

Xiao Cheng; Yanmei Zhang; E. Dongchen; Yun Shao

2003-01-01

260

Itâ??s good to be big--- Phaeocystis antarctica colony size under the influence of zooplankton grazers  

EPA Science Inventory

The haptophyte Phaeocystis antarctica forms extremely dense accumulations in the Ross Sea, Antarctica, and accounts for over 60% of the seasonal primary production. Similar to the Phaeocystis species in the northern hemisphere, P. antarctica exists as solitary cells and mucilagin...

261

ITâ??S GOOD TO BE BIGâ??PHAEOCYSTIS ANTARCTICA COLONY SIZE UNDER THE INFLUENCE OF ZOOPLANKTON GRAZERS  

EPA Science Inventory

The haptophyte Phaeocystis antarctica forms extremely dense accumulations in the Ross Sea, Antarctica, and accounts for over 60% of the seasonal primary production. Similar to the Phaeocystis species in the northern hemisphere, P. antarctica exists as solitary cells and mucilagin...

262

Occurrence and diversity of marine yeasts in Antarctica environments  

NASA Astrophysics Data System (ADS)

A total of 28 yeast strains were obtained from the sea sediment of Antarctica. According to the results of routine identification and molecular characterization, the strains belonged to species of Yarrowia lipolytica, Debaryomyces hansenii, Rhodotorula slooffiae, Rhodotorula mucilaginosa, Sporidiobolus salmonicolor, Aureobasidium pullulans, Mrakia frigida and Guehomyces pullulans, respectively. The Antarctica yeasts have wide potential applications in biotechnology, for some of them can produce ?-galactosidase and killer toxins.

Zhang, Xue; Hua, Mingxia; Song, Chunli; Chi, Zhenming

2012-03-01

263

Cretaceous and Tertiary extension throughout the Ross Sea, Antarctica  

Microsoft Academic Search

5 now at Shell Exploration & Production International B.V., Netherlands (Michael.Faulkner@shell.com) Abstract Marine geophysical data from the deep sea adjacent to the Ross Sea, Antarctica suggest that ?70 km of extension occurred between East and West Antarctica from 46 to 2? Ma. The Northern and V ictoria Land Basins in the western Ross Sea adjacent to the Transantarctic Mountains accommodated

Robert C. Decesari; Douglas S. Wilson; Bruce P. Luyendyk; Michael Faulkner

2007-01-01

264

Long time-series monitoring of the ecosystem at Deception Island, Antarctica: description of instrumentation  

NASA Astrophysics Data System (ADS)

A description of the oceanographic instrumentation developed and deployed at Deception Island, Antarctica during the period 9 March 1999 to 20 November 2000 as part of the ERUPT program is presented. This instrumentation includes (1) an autonomous weather station (Terrestrial station) to record daily conditions and ice-cover, (2) an underwater time-lapse camera/sediment trap array to photograph the abundance and movements of bottom-dwelling animals and collect sinking particulate matter, (3) an acoustic array to monitor movements of macrozooplankton and nekton, (4) an autonomous, vertically profiling pump sampler to capture and preserve plankton and nekton from discrete depths, (5) thermistor arrays to record water temperature at various depths, (6) an acoustic Doppler profiler to record current velocities at discrete depths, and (7) a piston-operated grab respirometer to measure sediment community oxygen consumption and recover sediments. The Terrestrial station and thermistor arrays, current meter and grab respirometer were the most successful instruments deployed, producing large data sets. The acoustic array produced some data of limited value, while the camera tripod and pump sampler produced no useful data due to technical and operational problems.

Glatts, R. C.; Uhlman, A. H.; Smith, K. L.; Baldwin, R. J.

2003-06-01

265

IESID: Automatic system for monitoring ground deformation on the Deception Island volcano (Antarctica)  

NASA Astrophysics Data System (ADS)

When establishing the relative distance between two GNSS-GPS stations with sub-centimeter accuracy, it is necessary to have auxiliary data, some of which can only be collected some time after the moment of measurement.However, for monitoring highly-active geodynamic areas, such as volcanoes and landslides, data precision is not as essential as rapid availability, processing of data in real-time, and fast interpretation of the results.This paper describes the development of an integrated automatic system for monitoring volcanic deformation in quasi real-time, applied to the Deception volcano (Antarctica). This experimental system integrates two independent modules that enable researchers to monitor and control the status of the GNSS-GPS stations, and to determine a surface deformation parameter. It comprises three permanent stations, one of which serves as the reference for assessing the relative distance in relation to the other two. The availability of GNSS-GPS data in quasi real-time is achieved by means of a WiFi infrastructure and automated data processing. This system provides, in quasi real-time, a time series of varying distances that tells us the extent to which any ground deformation is taking place.

Peci, Luis Miguel; Berrocoso, Manuel; Páez, Raúl; Fernández-Ros, Alberto; de Gil, Amós

2012-11-01

266

Yeast strains from Livingston Island, Antarctica.  

PubMed

Five yeast strains were isolated from soil and moss samples from the Livingston Island (Antarctica) and identified according to morphological cultural and physiological characteristics. All strains had an optimum growth temperature of 15 degrees C: none grew above 25 degrees C. They assimilated D-glucose, D-galactose, sucrose, cellobiose, trehalose, 2-keto-D-gluconate, D-xylose, D-ribose and melezitose. Four of them were nonfermentative, only one, which formed pseudomycelium fermented glucose, galactose, trehalose. Two strains were identified as pink-red yeasts belonging to genus Rhodotorula--R. minuta and R. mucilaginosa; two were related to the genus Cryptococcus--C. albidus and C. laurentii; one was Candida oleophila. PMID:11899471

Pavlova, K; Grigorova, D; Hristozova, T; Angelov, A

2001-01-01

267

The Derrick Peak, Antarctica, iron meteorites  

NASA Astrophysics Data System (ADS)

Sixteen iron meteorite specimens, Derrick Peak A78001 through DRPA78016, were recovered from the slopes of Derrick Peak, Antarctica, in 1978. Recovery from a relatively small area combined with their strikingly similar appearances suggest they represent a single fall. The metallographic structure of the two specimens that have been cut is dominated by regions of swathing kamacite enclosing coarse schreibersite and schreibersite-troilite inclusions. Patches of coarsest octahedrite Widmanstaetten structure are interspersed. Specimens DRPA78008 and DRPA78009 have been analyzed: 6.64, 6.59 wt % Ni; 0.51, 0.46 wt % Co; 0.35, 0.34 wt % P. The specimens are coarsest octahedrites of chemical group IIB.

Clarke, R. S., Jr.

1982-09-01

268

The Potential for Astronomy in Antarctica  

NASA Astrophysics Data System (ADS)

The extremely dry cold and tenuous air of the Antarctic plateau makes it the premier site on the earth for a wide range of astronomical observations especially at infrared and millimetre wavelengths. Background sky emission is one to two order of magnitudes less in intensity and new windows in the atmosphere are opened for viewing through. The high geomagnetic latitudes also make it particularly suitable for measurement of cosmic ray fluxes especially at low energy. The vast quantities of pure transparent ice provide for unparalled conditions for the measurement of neutrino fluxes. This talk will overview the potential of Antarctica for a wide range of astronomical observations conditions that surpass any other ground- based location in most circumstances. It will be an introductory lecture to the field designed for the non-specialist in Antarctic astronomy.

Burton, Michael G.

269

Nov. Total Solar Eclipse Observation from Antarctica  

NASA Astrophysics Data System (ADS)

PROGRAMME OF THE NOVEMBER 23/24 TOTAL SOLAR ECLIPSE OBSERVATION FROM ANTARCTICA A. Stoev1 P. Muglova2 1Yu. Gagarin Public Astronomical Observatory Stara Zagora Bulgaria 2Central Solar Terrestrial Influences Laboratory - Bulgarian Academy of Sciences Stara Zagora Department Bulgaria Observational tasks methods and instrumentation of the Total Solar Eclipse (TSE) South Pole’ 2003 program are presented in the paper. Photographic and video observations of the Sun during the different phases of the TSE are included in the programme. Basic aims of the programme are in the following directions: Investigation of the solar corona structure and microstructure dynamics and interrelation between different coronal elements and processes in time. Dust corona investigation. Experiments connected with atmospheric optic measurements actinometry and meteorology during the TSE.

Stoev, Alexey

270

Hypersaline “wet patches” in Taylor Valley, Antarctica  

NASA Astrophysics Data System (ADS)

Spatially isolated patches of soil located in Taylor Valley, McMurdo Dry Valleys, Antarctica, are sites of elevated salt content and soil moisture. During Antarctic spring, in the absence of snow melt, visibly wet (reduced albedo) patches of soil are present at the surface. The soil pore fluids are hypersaline and have average water activity of 0.74 (the water activity of a solution determines the equilibrium vapor pressure of that solution), and are an order of magnitude more saline than average soils in the Dry Valleys. These salty soils are 3-5 times more water rich than average soils. Geochemical and meteorological analyses show that these wet patches are sites of direct vapor emplacement into soil pore fluids that may ultimately be sourced by the deliquescence of soil salts. These wet patches represent a non-precipitation, non-groundwater source for water into Antarctic permafrost.

Levy, Joseph S.; Fountain, Andrew G.; Welch, Kathy A.; Lyons, W. Berry

2012-03-01

271

Photometry of Variables from Dome A, Antarctica  

NASA Astrophysics Data System (ADS)

Dome A on the Antarctic plateau is likely one of the best observing sites on Earth (Saunders et al. 2009). We used the CSTAR telescope (Yuan et al. 2008) to obtain time-series photometry of 104 stars with i>14.5 mag during 128 days of the 2008 Antarctic winter season (Wang et al. 2011). During the 2010 season we observed 2 × 104 stars with i>15 mag for 183 days (Wang et al. 2012). We detected a total of 262 variables, a 6 × increase relative to previous surveys of the same area and depth carried out from temperate sites (Pojmanski 2004). Our observations show that high-precision, long-term photometry is possible from Antarctica and that astronomically useful data can be obtained during 80% of the winter season.

Wang, Lingzhi; Macri, L. M.; Wang, L.; Ashley, M. C. B.; Cui, X.; Feng, L. L.; Gong, X.; Lawrence, J. S.; Liu, Q.; Luong-Van, D.; Pennypacker, C. R.; Shang, Z.; Storey, J. W. V.; Yang, H.; Yang, J.; Yuan, X.; York, D. G.; Zhou, X.; Zhu, Z.; Zhu, Z.

2013-01-01

272

Measurement Of Solar Radiation at New Delhi, High Altitude Observatory, Hanle and Maitri Antarctica  

NASA Astrophysics Data System (ADS)

The measurement of solar radiation plays an important role in climate and environmental change studies. The enhanced UV-B radiations at the ground level has the potential to cause adverse biological and environmental impacts. The amount of UV-B radiation at ground level depends on various temporal, spatial and meteorological factors such as time of the day, season, altitude, clouds, surface albedo, ozone, aerosols, etc. The risks for the human health, plant, animals and material are growing because of high exposition of the solar radiation which is caused by ozone depletion and other anthropogenic activities. A limited measurements have been made at high altitudes and Antarctica which are very crucial to inhabitants of these locations. In view of the above, measurements of solar radiation along with other parameters were carried out at Leh (34°77' N, 77°36' E), 3311 meter above mean sea level as well as at Indian Astronomical Observatory , Leh / Hanle ( Indian Institute of Astrophysics, Bangalore), Hanle (Mount Saraswati), Jammu and Kashmir (India) (32°43' N, 77°34' E), 4467 meter above mean sea level during July 13-31, 1999, June 2000 and July 2003 in a campaign mode. These measurements are first of its kind at a unique location well deep inside the troposphere as it happens to be one of the highest observatory in the world. The regular measurements are also being carried out at NPL, New Delhi(280 65^' N, 770 21^' E) and Maitri, Antarctica(70.440 S, 11.450 E). Also the data were collected during our voyage to Antarctica to cover latitudinal distribution of these parameters from Goa, India (15.240 N, 73.420 E) to Maitri, Antarctica (70.440 S, 11.450 E) using a highly sophisticated and microprocessor based compact hand held sun photometer consisting of five filter channels at 300, 305, 312, 940 and 1020 nm to measure solar radiation at all the sites. The measurements were used to derive total column ozone, water vapour and aerosol optical depth etc. The solar radiation at 305 nm was found to be an order of magnitude higher at Hanle and Antarctica compared to that at a low altitude station like Delhi. The effect of these intense radiation was easily seen on the faces of the local inhabitants particularly those working in open field at Hanle/Leh. The water vapour was found to be one tenth at Hanle and Maitri as compared to Delhi and therefore Hanle and Maitri are very good sites for astronomical studies. The column ozone measured at Maitri showed that the ozone hole during spring of 2002 was not as deep as that during 1997 and was for less duration while again it was very deep and for a longer duration during 2003. The variability in the ozone hole in different years is attributed to the dynamics and meteorological conditions prevailing over Antarctica. The data obtained at these experimental sites may provide base line / reference values for various environmental parameters. In the present communication the salient features of the instruments used and results obtained will be discussed in detail.

Jain, S. L.; Arya, B. C.

273

Psychophysiological Correlates of Human Adaptation in Antarctica.  

National Technical Information Service (NTIS)

Previous research has pointed to social, psychological, and occupational characteristics of Antarctic station personnel as contributing to variations in emotional symptoms commonly experienced during the prolonged isolation of the winter-over period. Howe...

E. K. Gunderson L. A. Palinkas R. G. Burr

1989-01-01

274

Benthic infaunal communities across the Weddell Sea Basin and South Sandwich Slope, Antarctica  

NASA Astrophysics Data System (ADS)

The present study represents the first quantitative investigation of deep-sea benthic infauna in Antarctica. Box cores and multicores were used to collect sediment from 12 stations across the slope and abyssal basin of the Weddell Sea and the slope off the South Sandwich Islands, including sites in the South Sandwich Trench (6300 m). The multicore was a more efficient sampler than the box core. Nine phyla of invertebrates were found, dominated by annelids (67%), crustaceans (20%); other phyla (13%). A total of 117 taxa were identified to the species level: 72 were polychaetes; 45 were crustaceans. Many taxa are new to science. Highest densities were at the 1000 m depth on the western slope of the Weddell Sea (260 individuals per 0.1 m -2) and at ca. 2200 m on the South Sandwich Slope (132 individuals per 0.1 m -2); lowest densities were in the central Weddell Sea Basin (39 individuals per 0.1 m -2). Species richness and rarefaction analysis suggest that the fauna is undersampled. The 117 species identified in this study were represented by only 237 specimens, indicating that species were being added at a rate of one species for every two specimens collected. Rarefaction curves do not begin to reach an asymptote supporting high estimates of diversity. Some species appear to be limited to distinct zones in upper and middle slope depths, other species extend from the slope to the abyssal basin, and at least two species appear to be restricted to the abyssal basin. In general, the densities of infauna on the slopes surrounding the Weddell Sea Basin have lower densities than well-studied areas off North America. However, abyssal populations in Antarctica appear to have denser infaunal populations than those from off New England and the North Pacific Gyre. Productive surface waters of the Weddell Sea and subsequent sinking of phytoplankton to the seabed are probable reasons for the higher benthic productivity in Antarctic abyssal sediments. Similarity analyses were not informative because so few species were collected. Two stations in the Weddell Abyssal Basin were the only ones to exhibit a high level of similarity due to two shared polychaetes. Data on reproductive status of some polychaetes suggest that species limited to abyssal depths are reproducing there. Other species with broader depth ranges may be receiving recruits from slope depths. The results suggest that the deep-water infauna in Antarctica is largely endemic, but has some components that occur along other continental margins and adjacent abyssal basins.

Blake, James A.; Narayanaswamy, Bhavani E.

2004-07-01

275

TV Station Authorization Report.  

National Technical Information Service (NTIS)

A list of cable television stations authorized to broadcast television station programs identified by call letters and location is given. This includes the community name, the cable television operator's legal name, and the number of subscribers for each ...

1979-01-01

276

MISU Baseline Station.  

National Technical Information Service (NTIS)

The MISU (acronym for University of Stockolm Department of Meteorology) baseline monitoring stations for CO2 and aerosol particles is described. The station is the result of ten years of instrumental development and field experiments on Spitsbergen (Swede...

J. Heintzenberg J. Ogren S. Odh L. Baecklin T. Danielsen

1991-01-01

277

Prognoz, Automatic Stations.  

National Technical Information Service (NTIS)

The Prognoz space stations launched by the Soviet Union during 1972 are discussed. The stations were designed to study solar activity and its influence on the interplanetary medium and on the earth's magnetosphere. The scientific instrumentation aboard th...

V. A. Arkhipov

1974-01-01

278

The cryptoendolithic microbial environment in the Ross Desert of Antarctica: satellite-transmitted continuous nanoclimate data, 1984 to 1986.  

PubMed

A satellite mediated station for monitoring nanoclimate (climate in the millimeter range) data, suitable for use in polar regions is described. The station, located in the Ross desert of Antarctica, has been in operation for more than 3 years, measuring rock temperatures, air temperature, light, snow, wind, and moisture. The data indicate that biological activity in the cryptoendolithic microbial ecosystem is limited to the period from mid November to mid February. The total number of hours of biological activity, based on assumptions of the minimum light, temperature and moisture requirements of the community, is less than 1000 h/year. The time above 0 degrees C, representing more nearly optimal conditions, is between 50 and 550 h/year, depending on the orientation of the surface. PMID:11539048

Friedmann, E I; McKay, C P; Nienow, J A

1987-01-01

279

Secure base stations  

Microsoft Academic Search

With the introduction of the third generation (3G) Universal Mobile Telecommunications System (UMTS) base station router (BSR) and fourth generation (4G) base stations, such as the 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) Evolved Node B (eNB), it has become important to secure base stations from break-in attempts by adversaries. While previous generation base stations could be considered

Peter Bosch; Alec Brusilovsky; Rae Mclellan; Sape J. Mullender; Paul A. Polakos

2009-01-01

280

The International Space Station  

NSDL National Science Digital Library

Users can access news articles, background information and links about the International Space Station. Materials presented here include crew biographies, expedition press kits, accounts of science experiments, and imagery taken from the station. Other features include a clock/counter that logs the station's and the crew's time in orbit and information for ground-based observers who wish to view the station as it passes overhead at night.

281

COMPARISON OF THE PETRIFIED WOODS FROM THE CRETACEOUS AND TERTIARY OF ANTARCTICA AND PATAGONIA  

Microsoft Academic Search

Mentioned is a brief history of the studies on the petrified woods from the Cretaceous and Tertiary of Antarctica and Patagonia. Among nine fossil species described from Antarctica so far, seven were recog- nized to occur also in Patagonia. It is suggested that the species from Patagonia are expected to be found from Antarctica in the near future. Four species

Makoto NISHIDA; Harufumi NISHIDA; Takeshi OHSAWA

282

Site testing for submillimetre astronomy at Dome C, Antarctica  

NASA Astrophysics Data System (ADS)

Aims: Over the past few years a major effort has been put into the exploration of potential sites for the deployment of submillimetre astronomical facilities. Amongst the most important sites are Dome C and Dome A on the Antarctic Plateau, and the Chajnantor area in Chile. In this context, we report on measurements of the sky opacity at 200 ?m over a period of three years at the French-Italian station, Concordia, at Dome C, Antarctica. We also present some solutions to the challenges of operating in the harsh polar environment. Methods: The 200-?m atmospheric opacity was measured with a tipper. The forward atmospheric model MOLIERE (Microwave Observation LIne Estimation and REtrieval) was used to calculate the atmospheric transmission and to evaluate the precipitable water vapour content (PWV) from the observed sky opacity. These results have been compared with satellite measurements from the Infrared Atmospheric Sounding Interferometer (IASI) on Metop-A, with balloon humidity sondes and with results obtained by a ground-based microwave radiometer (HAMSTRAD). In addition, a series of experiments has been designed to study frost formation on surfaces, and the temporal and spatial evolution of thermal gradients in the low atmosphere. Results: Dome C offers exceptional conditions in terms of absolute atmospheric transmission and stability for submillimetre astronomy. Over the austral winter the PWV exhibits long periods during which it is stable and at a very low level (0.1 to 0.3 mm). Higher values (0.2 to 0.8 mm) of PWV are observed during the short summer period. Based on observations over three years, a transmission of around 50% at 350 ?m is achieved for 75% of the time. The 200-?m window opens with a typical transmission of 10% to 15% for 25% of the time. Conclusions: Dome C is one of the best accessible sites on Earth for submillimetre astronomy. Observations at 350 or 450 ?m are possible all year round, and the 200-?m window opens long enough and with a sufficient transparency to be useful. Although the polar environment severely constrains hardware design, a permanent observatory with appropriate technical capabilities is feasible. Because of the very good astronomical conditions, high angular resolution and time series (multi-year) observations at Dome C with a medium size single dish telescope would enable unique studies to be conducted, some of which are not otherwise feasible even from space.

Tremblin, P.; Minier, V.; Schneider, N.; Durand, G. Al.; Ashley, M. C. B.; Lawrence, J. S.; Luong-van, D. M.; Storey, J. W. V.; Durand, G. An.; Reinert, Y.; Veyssiere, C.; Walter, C.; Ade, P.; Calisse, P. G.; Challita, Z.; Fossat, E.; Sabbatini, L.; Pellegrini, A.; Ricaud, P.; Urban, J.

2011-11-01

283

Dynamics and Evolution of Taylor Glacier, Antarctica  

NASA Astrophysics Data System (ADS)

Taylor Glacier is a high-stress outlet glacier of East Antarctica. It originates on the Taylor Dome, flows eastward through the Transantarctic Mountains, and terminates in the famous Dry Valleys of Victoria Land. Here we summarize results from extensive new studies on its 80 km long ablation zone. Radar surveys show the basal topography is dominated by a deeply eroded central trough. Force balance and flow analyses yield estimates for basal temperature and demonstrate that basal motion of this glacier is non-existent or minor. A full-stress three-dimensional model of ice flow with no approximations in the mathematical framework is used to examine in detail how the glacier negotiates the complex mountainous topography and how the nonlinearity of ice deformation is manifest. We have also measured the stable isotope profile of surface ice along the lower 27 km of the central flowline, and thereby inferred ages of the ice at some locations. Analysis of these data reveal time-dependent behavior of the glacier over millennial timescales. Time-dependent planview models of the system are used to explore past incursions of ice into Taylor Valley.

Cuffey, K. M.; Kavanaugh, J. L.; Morse, D. L.; Aciego, S.; Bliss, A.

2005-12-01

284

Hydrogen emissions from Erebus volcano, Antarctica  

NASA Astrophysics Data System (ADS)

The continuous measurement of molecular hydrogen (H2) emissions from passively degassing volcanoes has recently been made possible using a new generation of low-cost electrochemical sensors. We have used such sensors to measure H2, along with SO2, H2O and CO2, in the gas and aerosol plume emitted from the phonolite lava lake at Erebus volcano, Antarctica. The measurements were made at the crater rim between December 2010 and January 2011. Combined with measurements of the long-term SO2 emission rate for Erebus, they indicate a characteristic H2 flux of 0.03 kg s-1 (2.8 Mg day-1). The observed H2 content in the plume is consistent with previous estimates of redox conditions in the lava lake inferred from mineral compositions and the observed CO2/CO ratio in the gas plume (˜0.9 log units below the quartz-fayalite-magnetite buffer). These measurements suggest that H2 does not combust at the surface of the lake, and that H2 is kinetically inert in the gas/aerosol plume, retaining the signature of the high-temperature chemical equilibrium reached in the lava lake. We also observe a cyclical variation in the H2/SO2 ratio with a period of ˜10 min. These cycles correspond to oscillatory patterns of surface motion of the lava lake that have been interpreted as signs of a pulsatory magma supply at the top of the magmatic conduit.

Moussallam, Yves; Oppenheimer, Clive; Aiuppa, Alessandro; Giudice, Gaetano; Moussallam, Manuel; Kyle, Philip

2012-11-01

285

Characterizing and Predicting Surface Melt in Antarctica  

NASA Astrophysics Data System (ADS)

The presence of surface melting on ice sheets and ice shelves marks an important climatic and geophysical threshold in the cryosphere. Wetting of snow reduces albedo and encourages additional melt, meltwater runoff contributes to mass loss from ice sheets, and penetration of meltwater to the glacier bed can lubricate faster flow and contribute to ice-sheet mass loss. Meltwater may also contribute to ice-shelf collapse through wedging open of crevasses. While fringing ice-shelf collapse along the Antarctic Peninsula is probably the best known example of the cryospheric response to a warming atmosphere (and ocean), surface melting is also present in inland portions of West Antarctica. In addition to potentially contributing to ice sheet dynamics, surface melt occurrence is a valuable proxy for changing atmospheric temperature conditions. Combining satellite remote sensing with atmospheric modeling, we diagnose the meteorological conditions associated with surface melting on the Antarctic ice sheet and its fringing ice shelves. With these results, we plan to predict whether the regional warming associated with anticipated anthropogenic global warming and related atmospheric circulation changes will lead to a future increase of melting. We present case studies of selected West Antarctic melt events that document the utility and skill of our meteorological datasets (reanalyses, RCMs, selected CMIP5 GCMs) in the development of diagnostic tools for identifying surface melt as observed by satellite and simulated by models.

Reusch, D. B.; Karmosky, C. C.; Lampkin, D. J.; Schneider, D. P.

2011-12-01

286

Observed Magnetic Declinations in West Antarctica  

Microsoft Academic Search

Filchner ice shelves. Six of these traverses included as part of their objectives periodic determinations of magnetic declination D. Declination observations were made at intervals of approximately 30 to 36 nautical miles on the oversnow traverses and at each of the seven stations occupied by the airborne traverse (Fig. H. O. map 1706S (1960). Here we see a remarkably good

Ned A. Ostenso; Charles R. Bentley

1961-01-01

287

Summary of Meteorological Observations, Surface (SMOS), McMurdo Station, Antarctica.  

National Technical Information Service (NTIS)

This data report consists of a six part statistical summary of surface weather observations. The six parts are: Part A - Weather Conditions/Atmospheric Phenomena, Part B - Precipitation/Snowfall/Snow Depth, Part C - Surface Winds, Part D - Ceiling versus ...

1978-01-01

288

A comparative study of protein synthesis in nototheniids and icefish at Palmer Station, Antarctica.  

PubMed

Protein synthetic rates were measured in tissues of Notothenia corriceps, N. gibberifrons and Chaenocephalus aceratus in vivo at 2 degrees C by a method in which high doses of 14C-phenylalanine are used for stabilization of specific radioactivity. Rates in N. coriiceps, as per cent of tissue protein synthesized per day, were: liver 10.4, head kidney 3.5, testis 2.6, spleen 2.1, kidney 1.9, gill 1.6, heart 1.4, pectoral muscle 1.0, epaxial muscle 0.37, brain 0.42. With the exception of liver and head kidney (9.8 and 3.4, respectively) all rates in the icefish C. aceratus were significantly reduced compared to the nototheniids, consistent with the dependence of protein synthesis on oxidative metabolism. Icefish lack hemoglobin in the blood. The effects of two-week starvation were tissue-specific. Rates declined markedly in pectoral and epaxial muscle, were unchanged in liver, kidney, brain, heart and testis, and were increased in gill and head kidney. The results are discussed in relation to cold adaptation of Antarctic fishes and to the adaptation of metabolism required during non-feeding periods and for species which lack an oxygen-binding pigment in their blood. PMID:6641175

Haschemeyer, A E

1983-01-01

289

Observations of Earth space by self-powered stations in Antarctica  

Microsoft Academic Search

Coupling of the solar wind to the Earth magnetosphere\\/ionosphere is primarily through the high latitude regions, and there are distinct advantages in making remote sensing observations of these regions with a network of ground-based observatories over other techniques. The Antarctic continent is ideally situated for such a network, especially for optical studies, because the larger offset between geographic and geomagnetic

S. B. Mende; W. Rachelson; R. Sterling; H. U. Frey; S. E. Harris; S. McBride; T. J. Rosenberg; D. Detrick; J. L. Doolittle; M. Engebretson; U. Inan; J. W. Labelle; L. J. Lanzerotti; A. T. Weatherwax

2009-01-01

290

The First Core Replacement Pm-3A Nuclear Power Plant, Mcmurdo Station, Antarctica.  

National Technical Information Service (NTIS)

Replacement of the first core at the PM-3A Nuclear Power Plant began on 21 November 1964, and was completed on 26 December 1964, with the plant reassembled for acceptance testing. The total elapsed time was 35 days. The report discusses the entire refueli...

P. D. Arrowsmith

1965-01-01

291

Shoring pumping station excavation  

Microsoft Academic Search

The city of San Mateo, Calif., operates three 12- to 50-year old wastewater pumping stations on a 24-m (80-ft) wide lot located in a residential area near San Francisco Bay. Because the aging stations have difficulty pumping peak 2.19-m³\\/s (50-mgd) wet-weather flows and have structural and maintenance problems, a new 2.62-m³\\/s (60-mgd) station was proposed - the Dale Avenue Pumping

J. B. Glover; D. J. Reardon

1991-01-01

292

The SCAR Astronomy & Astrophysics from Antarctica Scientific Research Programme  

NASA Astrophysics Data System (ADS)

SCAR, the Scientific Committee on Antarctic Research, is, like the IAU, a committee of ICSU, the International Council for Science. For over 30 years, SCAR has provided scientific advice to the Antarctic Treaty System and made numerous recommendations on a variety of matters. In 2010, Astronomy and Astrophysics from Antarctica was recognized as one of SCAR's five Scientific Research Programs. Broadly stated, the objectives of Astronomy & Astrophysics from Antarctica are to coordinate astronomical activities in Antarctica in a way that ensures the best possible outcomes from international investment in Antarctic astronomy, and maximizes the opportunities for productive interaction with other disciplines. There are four Working Groups, dealing with site testing, Arctic astronomy, science goals, and major new facilities. Membership of the Working Groups is open to any professional working in astronomy or a related field.

Storey, John W. V.; Abe, Lyu; Andersen, Michael; Anderson, Philip; Burton, Michael; Cui, Xiangqun; Ichikawa, Takashi; Karle, Albrecht; Lloyd, James; Masi, Silvia; Steinbring, Eric; Travouillon, Tony; Tuthill, Peter; Zhou, HongYang

2013-01-01

293

Seismic anisotropy beneath Dronning Maud Land, Antarctica, revealed by shear wave splitting  

NASA Astrophysics Data System (ADS)

Shear wave splitting analyses have been carried out using teleseismic data from broad-band seismograph stations deployed at temporary and permanent locations in Dronning Maud Land (DML), Antarctica. In most cases, the observed anisotropy can be related to major tectonic events that formed the present-day Antarctic continent. We rule out an anisotropic contribution from recent asthenospheric flow. At the Russian base Novolazarevskaya near the coast in central DML, waveform inversion suggests a two-layer model where the fast direction of the upper layer is oriented parallel to Archean fabrics in the lithosphere, whereas the anisotropy of the lower layer is interpreted to have been created during the Jurassic Gondwana break-up. Recordings at the South African base Sanae IV, however, show enigmatic results. For narrow backazimuthal segments, splitting parameters show strong variations together with a multitude of isotropic measurements, indicative of complex scattering that cannot be explained by simple one- or two-layer anisotropic models. In the interior of the continent, the data are consistent with single-layer anisotropy, but show significant spatial variations in splitting parameters. A set of temporary stations across the Heimefront shear zone in western DML yield splitting directions that we interpret as frozen anisotropy from Proterozoic assembly of the craton. An abrupt change in fast axis direction appears to mark a suture between the Grunehogna craton, a fragment of the Kalahari-Kaapvaal craton in southern Africa and the Mesoproterozoic Maudheim Province.

Bayer, Bettina; Müller, Christian; Eaton, David W.; Jokat, Wilfried

2007-10-01

294

Balloon-borne observations of stratospheric aerosol in Antarctica from 1972 to 1984  

NASA Astrophysics Data System (ADS)

Stratospheric levels of particles with r or = 0.15 microns were monitored with optical particle counters in approximately monthly balloon soundings at Laramie, Wyoming (41 deg N) since 1971. These measurements were used to characterize the background stratospheric aerosol layer and the disturbed layer following major volcanic eruptions. Levels of particles with r or = 0.01 microns have also been measured with balloon-borne counters since 1973. The latter are collectively called condensation nuclei (CN) as they are characteristic of aerosol in the early stages of growth. While they dominate the size distribution in the tropsophere, they are a trace species in the undisturbed stratosphere. From 1972 until 1980, annual balloon soundings from McMurdo Station (78 deg S) and/or Amundsen-Scott Station (90 deg S), in Antarctica, have also been conducted to crudely monitor Southern Hemisphere aerosol levels. These measurements were continued in 1983 and 1984. Profiles of r 0.15 microns aerosol concentrations as measured during January at the south pole from 1972 to 1975 and in 1980 are given. The former are typical of undisturbed conditions and indicate the small degree of variability under these conditions. The latter indicates the effect of minor volcanic activity, visible in the 10 to 15 km region.

Hofmann, D. J.

1985-12-01

295

The first record of a sauropod dinosaur from Antarctica  

NASA Astrophysics Data System (ADS)

Sauropoda is one of the most diverse and geographically widespread clades of herbivorous dinosaurs, and until now, their remains have now been recovered from all continental landmasses except Antarctica. We report the first record of a sauropod dinosaur from Antarctica, represented by an incomplete caudal vertebra from the Late Cretaceous of James Ross Island. The size and morphology of the specimen allows its identification as a lithostrotian titanosaur. Our finding indicates that advanced titanosaurs achieved a global distribution at least by the Late Cretaceous.

Cerda, Ignacio A.; Paulina Carabajal, Ariana; Salgado, Leonardo; Coria, Rodolfo A.; Reguero, Marcelo A.; Tambussi, Claudia P.; Moly, Juan J.

2012-01-01

296

Live from Antarctica 2: Oceans, Ice and Life  

NSDL National Science Digital Library

This page furnishes the background for a group of activities investigating living things in Antarctica centered around a voyage aboard the research vessel Polar Duke from South America to Antarctica. It describes the ship and the people aboard and discusses their duties and areas of research. There is also an account of the wreck of the Argentine supply and cruise ship, Bahia Paraiso which spilled 200,000 gallons of diesel and jet fuel into some of the most pristine waters on Earth, and a description of the Palmer Long-Term Ecological Research project (LTER), which began partly as a reponse ot the wreck.

297

The Center for Astrophysical Research in Antarctica (CARA)  

NSDL National Science Digital Library

The Center for Astrophysical Research in Antarctica (CARA) investigates the origin of structure in the Universe by using the unique advantages of the Polar Plateau for astrophysics. The site has links to the latest happenings at CARA, what CARA is, why they go to the South Pole, and information on the science that is done from the South Pole. There is also an overview of CARA education and outreach programs, and a collection of photographs including Virtual Antarctica. For kids, there is a link to the South Pole Adventure Page which features a set of experiments, a question and answer section, photos, and links to webcams.

298

Climate change during the last deglaciation in Antarctica  

SciTech Connect

Greenland ice core records provide clear evidence of rapid changes in climate in a variety of climate indicators. In this work, rapid climate change events in the Northern and Southern hemispheres are compared on the basis of an examination of changes in atmospheric circulation developed from two ice cores. High-resolution glaciochemical series, covering the period 10,000 to 16,000 years ago, from a central Greenland ice core and a new site in east Antarctica display similar variability. These findings suggest that rapid climate change events occur more frequently in Antarctica than previously demonstrated. 21 refs,. 2 figs.

Mayewski, P.A.; Twickler, M.S.; Whitlow, S.I. [and others

1996-06-14

299

Environmental signals in a highly resolved ice core from James Ross Island, Antarctica  

NASA Astrophysics Data System (ADS)

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, satellite and reanalysis data allows for a detailed assessment of the environmental information preserved in the ice. Accumulation at James Ross Island is enhanced during years when the circumpolar westerlies are weak, allowing more precipitation events to reach the northeastern Antarctic Peninsula. The stable water isotope composition of the ice core has an interannual temperature dependence consistent with the spatial isotope-temperature gradient across Antarctica, and preserves information about both summer and winter temperature variability in the region. Sea salts in the ice core are derived from open water sources in the marginal sea ice zone to the north of James Ross Island and transported to the site by strengthened northerly and westerly winds in the winter. A strong covariance with temperature means that the sea salt record may be able to be utilized, in conjunction with the isotope signal, as an indicator of winter temperature. Marine biogenic compounds in the ice core are derived from summer productivity within the sea ice zone to the south of James Ross Island. This source region may have become significant only in recent decades, when the collapse of nearby ice shelves established new sites of open water with high summer productivity. These findings provide a foundation for interpreting the environmental signals in the James Ross Island ice core, which extends though the whole Holocene and represents the oldest ice core that has been recovered from the Antarctic Peninsula region.

Abram, Nerilie J.; Mulvaney, Robert; Arrowsmith, Carol

2011-10-01

300

Auroral images and particle precipitations observed by S-310JA-8, -9, and -10 at Syowa Station  

NASA Astrophysics Data System (ADS)

Three sounding rockets launched in 1984 from Syowa Station, Antarctica, into different types of aurora obtained auroral pictures and measured the energy spectra of auroral particles. The active auroral arc at the substorm expansion phase displayed greater values of auroral emission and electron density than the stable arc prior to the substorm onset. The diffuse aurora during the recovery stage showed enhancement in the D-region.

Ejiri, Masaki; Ono, Takayuki; Hirasawa, Takeo; Oguti, Takasi

301

Future Weather Station  

NSDL National Science Digital Library

In this activity students build dioramas of futuristic weather stations to demonstrate their knowledge of weather forecasting. They will work in groups to research modern forecasting equipment and techniques, and then build a weather station that will do something we cannot do at present (such as stopping tornadoes). They will present their dioramas and then discuss the pros and cons of controlling the weather.

302

Reliability of Seismograph Stations  

Microsoft Academic Search

IN a recent paper, Dr. H. Jeffreys1 works out a `reliability' factor for seismograph stations throughout the world, using information from the International Seismological Summary for 1930 January to 1931 March. Reliability results based on this information do not, however, represent present conditions. Seismology has made rapid headway since 1931, and a number of stations have improved both their recording

R. C. Hayes

1936-01-01

303

"Inventive" Learning Stations  

ERIC Educational Resources Information Center

|Learning stations can be used for myriad purposes--to teach concepts, integrate subject matter, build interest, and allow for inquiry--the possibilities are limited only by the imagination of the teacher and the supplies available. In this article, the author shares suggestions and a checklist for setting up successful learning stations. In…

Jarrett, Olga

2010-01-01

304

Station Tour: Russian Segment  

NASA Video Gallery

Expedition 33 Commander Suni Williams concludes her tour of the International Space Station with a visit to the Russian segment, which includes Zarya, the first segment of the station launched in 1998, and Zvezda, the central command post. She also takes a look at the Poisk and Rassvet modules where Soyuz spacecraft are docked.

Gerald T Wright

2012-11-20

305

Small transportable earth station  

Microsoft Academic Search

This paper describes design and performance of C band (6\\/4 GHz) and K band (30\\/20 GHz) small transportable earth station for domestic satellite communication. These stations consist of three units, an antenna and two containers. Transmitter and receiver equipments are mounted in one container. Terminal equipment and power generator are mounted in the other container, thus enabling transportation by truck

S. Egami; T. Nara; T. Kaitsuka; T. Okamoto

1980-01-01

306

Multi-decadal surface temperature trends in the East Antarctica using borehole firn temperature measurements and geophysical inverse method  

NASA Astrophysics Data System (ADS)

The interior of East Antarctic Ice Sheet (EAIS) remains one of the least explored areas on earth and as a result, its climate is one of the least-understood as well. Recent studies with techniques utilizing sparse available records and models have estimated a weak warming trend in East Antarctica for the past 50 years. However, these are not without uncertainties and additional data sources are needed in order to gain a better assessment of the East Antarctic climate trend. The objective of this investigation is to detect multi-decadal surface temperature trends in the interior of East Antarctica. Surface temperature inversion from vertical firn temperature profile measurements at several locations provides a source of climate reconstruction independent of firn chemistry, sparse weather data, satellite data, or ice cores. During the Norwegian-U.S. IPY Scientific Traverse of East Antarctica, in austral summers of 2007-08 and 2008-09, thermal-profiling units were installed at five locations. Each unit consists of 16 PRTs (Platinum Resistance Thermometers) distributed between depths of 0.15 and approximately 90 m. Wired PRTs were lowered into the borehole after an ice core was drilled and before the hole was back-filled with granulated snow to prevent air circulation and provide thermal conduction between PRTs and firn. Near-hourly data are being transmitted through ARGOS satellite telemetry system. The overall uncertainty in firn temperature measurement is 0.03 °C. A geophysical inverse method using the generalized inverse and regularization method was applied to one full year of data collected from three units installed in 2007-08. Results indicate that the recent decade is approximately 0.5 to 0.8 °C warmer than ~100 years ago, given assumptions on physical characteristics of the ice sheet (accumulation rate, geothermal heat flux, vertical advection, density and thermal properties). However, the precise onset and rate of the warming are undetermined at this stage. We will also present the preliminary results from the two sites installed in 2008-09 season, as well as the use of Monte Carlo inverse method. Initial analysis suggests that the southern station supports the results of the earlier stations but the near-coastal station near Kohnen appears to indicate a more significant warming.

Muto, A.; Scambos, T.; Steffen, K.

2009-12-01

307

Pseudonocardia antarctica sp. nov. an Actinomycetes from McMurdo Dry Valleys, Antarctica.  

PubMed

Strain DVS 5a1 was isolated from a moraine sample from the McMurdo Dry Valleys region of Antarctica. The strain is aerobic, Gram-positive, with white aerial mycelia and brown substrate mycelia, sporulating, has meso-diaminopimelic acid, arabinose and galactose in the cell wall, MK-8 (H4) as the major menaquinone and a mol% G+C content of DNA of 71% thus confirming to the description of the genus Pseudonocardia. Phylogenetic analysis based on the 16S rRNA gene sequence analysis further confirms that DVS 5al which forms a robust clade with P. alni, P. compacta, P. autotrophica and P. kongjuensis is closely related to the genus Pseudonocardia and exhibits maximum similarity of 99.7% with Pseudonocardia alni. However, at whole genome level as determined by DNA-DNA hybridisation DVS 5al exhibits a similarity of only 50% with Pseudonocardia alni. Further, DVS 5al differs from Pseudonocardia alni in that it does not produce acid from D-arabinose, meso-erythritol, melizitose, sorbitol, sucrose, D-trehalose; but produces acid from D-mannitol, D-galactose, D-maltose, D-mannose, inulin, D-ribose and D-xylose. Further, compared to Pseudonocardia alni, it has two additional fatty acids namely Me-C(18:0) and Me-C(19:0) and also possesses one additional unidentified lipid. It also shows distinct differences with P. compacta, P. autotrophica and P. kongjuensis and the other species of Pseudonocardia. It is proposed to assign DVS 5a1 the status of a new species for which the name Pseudonocardia antarctica sp. nov. is suggested. PMID:15053323

Prabahar, Vadivel; Dube, Smita; Reddy, G S N; Shivaji, S

2004-02-01

308

4. EASTBOUND VIEW. NORTH TRACK WAITING STATION ON LEFT. STATION ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

4. EASTBOUND VIEW. NORTH TRACK WAITING STATION ON LEFT. STATION ON RIGHT. NOTE TUNNEL IN BACKGROUND. - Baltimore & Ohio Railroad, Harpers Ferry Station, Potomac Street, Harpers Ferry, Jefferson County, WV

309

The Berkner Island (Antarctica) ice-core drilling project  

Microsoft Academic Search

We describe a project to retrieve a 948 m deep ice core from Berkner Island, Antarctica. Using relatively lightweight logistics and a small team, the drilling operation over three austral summer seasons used electromechanical drilling technology, described in detail, from a covered shallow pit and a fluid-filled borehole. A basal temperature well below pressure-melting point meant that no drilling problems

Robert Mulvaney; Olivier Alemany; Philippe Possenti

2007-01-01

310

Epilithic lichens in the Beacon sandstone formation, Victoria Land, Antarctica.  

PubMed

The epilithic lichen flora on the Beacon sandstone formation in Victoria Land consists of seven species: Acarospora gwynnii Dodge & Rudolph, Buellia grisea Dodge & Baker, B. pallida Dodge & Baker, Carbonea capsulata (Dodge & Baker) Hale comb. nov., Lecanora fuscobrunnea Dodge & Baker, Lecidea cancriformis Dodge & Baker, and L. siplei Dodge & Baker. The typification of the species is given along with descriptions and distribution in Antarctica. PMID:11539716

Hale, M E

1987-01-01

311

Antarctica: Arena for South American Cooperation or Conflict.  

ERIC Educational Resources Information Center

|A number of converging circumstances suggest that Antarctica may be a major object of geopolitical attention in South America in the decade to come. The Malvinas/Falklands crisis focused geopolitical attention on the South Atlantic and the chain of Southern (Austral) Islands which link the southern tip of South America to the Antarctic Peninsula.…

Child, Jack

312

Isolation of five strains of thermophilic eubacteria in Antarctica  

Microsoft Academic Search

Five isolates of thermophilic bacteria, capable of growing at 65°C, were obtained from samples of soil collected from the Cryptogam Ridge (Mount Melbourne) and in the area north of Edmonson Point, Northern Victoria Land, Antarctica. Electron microscopy, morphological and physiological properties, lipid analyses and GC content of the isolates are described in this paper. On the basis of the results

B. Nicolaus; F. Marsiglia; E. Esposito; A. Trincone; L. Lama; R. Sharp; G. di Prisco; A. Gambacorta

1991-01-01

313

Antarcticite: A New Mineral, Calcium Chloride Hexahydrate, Discovered in Antarctica  

Microsoft Academic Search

A new mineral, calcium chloride hexahydrate, was discovered in the Don Juan Pond in Victoria Land, Antarctica. The optical properties, chemical analysis, and powder patterns obtained by x-ray diffraction agree with those of artificial calcium chloride hexahydrate. The name Antarcticite is proposed for the new mineral.

Tetsuya Torii; Joyo Ossaka

1965-01-01

314

Azimuth variation in microwave scatterometer and radiometer data over Antarctica  

Microsoft Academic Search

While designed for ocean observation, scatterometer and radiometer data have proven very useful in a variety of cryosphere studies. Over large regions of Antarctica, ice sheet and bedrock topography and the snow deposition, drift, and erosional environment combine to produce roughness on various scales. Roughness ranges from broad, basin-scale ice-sheet topography at ~100 km wavelengths to large, spatially coherent dune

David G. Long; Mark R. Drinkwater

2000-01-01

315

Nest selection by snow petrels Pagodroma nivea in East Antarctica  

Microsoft Academic Search

Little is known on the factors controlling distribution and abundance of snow petrels in Antarctica. Studying habitat selection through modeling may provide useful information on the relationships between this species and its environment, especially relevant in a climate change context, where habitat availability may change. Validating the predictive capability of habitat selection models with independent data is a vital step

Frédérique Olivier; Simon J. Wotherspoon

2008-01-01

316

Results and Error Estimates from GRACE Forward Modeling over Antarctica  

NASA Astrophysics Data System (ADS)

Forward modeling using a weighted least squares technique allows GRACE information to be projected onto a pre-determined collection of local basins. This decreases the impact of spatial leakage, allowing estimates of mass change to be better localized. The technique is especially valuable where models of current-day mass change are poor, such as over Antarctica. However when tested previously, the least squares technique has required constraints in the form of added process noise in order to be reliable. Poor choice of local basin layout has also adversely affected results, as has the choice of spatial smoothing used with GRACE. To develop design parameters which will result in correct high-resolution mass detection and to estimate the systematic errors of the method over Antarctica, we use a "truth" simulation of the Antarctic signal. We apply the optimal parameters found from the simulation to RL05 GRACE data across Antarctica and the surrounding ocean. We particularly focus on separating the Antarctic peninsula's mass signal from that of the rest of western Antarctica. Additionally, we characterize how well the technique works for removing land leakage signal from the nearby ocean, particularly that near the Drake Passage.

Bonin, Jennifer; Chambers, Don

2013-04-01

317

Antarctica I: Deep structure investigations inferred from seismology; a review  

Microsoft Academic Search

The strategic position of Antarctica and its role have always been seen as clues to the tectonic and geodynamic history of the southern hemisphere. Direct investigations are difficult, and seismology was, and still is, a very efficient tool for answering some important questions. Major seismological results from the beginning of the century to the present are reviewed, taking into consideration

G. Roult; D. Rouland

1994-01-01

318

Cold tolerance in Tardigrada from Dronning Maud Land, Antarctica  

Microsoft Academic Search

Survival at low temperatures was studied in three species of Tardigrada from Müihlig-Hofmannfjella, Dronning Maud Land, Antarctica. Both hydrated and dehydrated specimens of Echiniscus jenningsi, Macrobiotus furciger and Diphascon chilenense had high survival rates following exposure to -22°C for ca. 600 days, and dehydrated specimens following 3040 days at this temperature. In hydrated E. jenningsi, mortality increased with the duration

Lauritz Sømme; Terje Meier

1995-01-01

319

Dynamical Constraints on Katabatic Wind Cessation in Adélie Land, Antarctica  

Microsoft Academic Search

The katabatic wind events observed in the coastal zone of Adélie Land, Antarctica, on 27 November and 3 December 1985 are simulated with a hydrostatic mesoscale atmospheric model coupled to a snow model. The diurnal cycle of insolation is strong. The main difference in the forcing between the two events is the large-scale wind, which is weak on 27 November

Hubert Gallée; Paul Pettré

1998-01-01

320

A POSSIBLE ENDOPARASITIC CHYTRIDIOMYCETE FUNGUS FROM THE PERMIAN OF ANTARCTICA  

Microsoft Academic Search

Several stages of the life cycle of an endoparasitic fungus of the Chytridiomycota, here assigned to the extant genus Synchtrium, are described as the new species per- micus from silicified plant remains from the Late Permian (~250 Ma) of Antarctica. The thallus of Synchtrium permicus is holocarpic and monocentric and consists of thick- walled resting sporangia, thin-walled sporangia, and zoospores

J. L. García Massini

321

Abandoned penguin rookeries as Holocene paleoclimatic indicators in Antarctica  

Microsoft Academic Search

Penguins are sensitive indicators of the Antarctic climate and of the environmental parameters that limit their presence and distribution. Paleoenvironmental data, obtained from the study of abandoned penguin rookeries (Pygoscelis adeliae) along the Victoria Land coast in Antarctica, indicate 14C date of 11-13 ka for the oldest abandoned rookery and supply new information about the timing of glacier retreat in

Carlo Baroni; Giuseppe Orombelli

1994-01-01

322

Heart Rate Variability on Exposure to Severe Gold at Antarctica  

Microsoft Academic Search

An attempt has been made to evaluate Heart Rate Variability (HRV) as a reliable index for sympathetic and parasympathetic components of the autonomic nervous system response during the course of acclimatization to severe cold at Antarctica. Two groups (10 each) of healthy men in the age group of 2344 years participated in the study. Group A consisted of fresh inductees

K. Harinath; A. S. Malhotra; Karan Pal; R. Prasad; R. C. Sawhney

323

Postspreading rifting in the Adare Basin, Antarctica: Regional tectonic consequences  

Microsoft Academic Search

Extension during the middle Cenozoic (43–26 Ma) in the north end of the West Antarctic rift system (WARS) is well constrained by seafloor magnetic anomalies formed at the extinct Adare spreading axis. Kinematic solutions for this time interval suggest a southward decrease in relative motion between East and West Antarctica. Here we present multichannel seismic reflection and seafloor mapping data

R. Granot; S. C. Cande; J. M. Stock; F. J. Davey; R. W. Clayton

2010-01-01

324

New Aerogeophysical exploration of the Gamburtsev Province (East Antarctica)  

Microsoft Academic Search

The enigmatic Gamburstev Subglacial Mountains (GSM) in the interior of East Antarctica, have remained the least understood mountain range on earth, since their discovery some 50 years ago. An improved knowledge of the GSM region is however essential to underpin reconstructions of the Antarctic cryosphere and climate evolution. The GSM are a key nucleation site for the inception of the

F. Ferraccioli; R. E. Bell; M. Studinger; D. Damaske; T. A. Jordan; H. Corr; D. A. Braaten; P. S. Gogineni; M. A. Fahnestock; C. Finn; K. Rose

2009-01-01

325

Looking for Life in Antarctica  and on Mars  

NSDL National Science Digital Library

This online article, from Earth: Inside and Out, reports on the search for microscopic organisms on Earth and Mars. It discusses the work of Chris McKay, an astrobiologist with NASA, the planetary similarities between Earth and Mars and current research in the valleys of Antarctica.

326

Influence of tides and tidal current on Mertz Glacier, Antarctica  

Microsoft Academic Search

Mertz Glacier, East Antarctica, is characterized by a 140 km long, 25 km wide floating ice tongue. In this paper, we combine a large number of remotely sensed datasets, including in situ global positioning system measurements, satellite radar altimetry, airborne radio-echo sounding and satellite synthetic aperture radar imagery and interferometry. These various datasets allow us to study the interaction of

Benoît Legrésy; Anja Wendt; Ignazio Tabacco; Frédérique Rémy; Reinhard Dietrich

2004-01-01

327

Influx of meltwater to subglacial Lake Concordia, East Antarctica  

Microsoft Academic Search

We present evidence for melting at the base of the ice that overlies Lake Concordia, an 800 km2 subglacial lake near Dome Concordia, East Antarctica, via a combination of glaciohydraulic melting (associated with the tilted ice ceiling and its influence on lake circulation\\/melting temperature) and melting by extreme strain heating (where the ice sheet is grounded). An influx of water

Anahita A. Tikku; Robin E. Bell; Michael Studinger; Garry K. C. Clarke; Ignazio Tabacco; Fausto Ferraccioli

2005-01-01

328

Influence of tides and tidal current on Mertz Glacier Antarctica  

Microsoft Academic Search

ABSTRACT. Mertz Glacier, East Antarctica, is characterized by a 140 km long, 25 km wide floating ice tongue. In this paper, we combine a large number of remotely sensed datasets, including in situ global positioning system measurements, satellite radar al- timetry, airborne radio-echo sounding and satellite synthetic aperture radar imagery and interferometry. These various datasets allow us to study the

Benoi Tl Egre Sy; Anja Wendt; Ignazio Tabacco; Fre De Rique Re My

329

Redefinition of the Amery Ice Shelf, East Antarctica, grounding zone  

Microsoft Academic Search

New evidence is presented which shows that the Amery Ice Shelf, East Antarctica, extends ~240 km upstream of the previously reported position. We combine a digital elevation model of the Amery Ice Shelf created from ERS-1 satellite radar altimetry with measured ice thicknesses and a simple density model in a hydrostatic (buoyancy) calculation to map the extent of the floating

Helen Amanda Fricker; Ian Allison; Mike Craven; Glenn Hyland; Andrew Ruddell; Neal Young; Richard Coleman; Matt King; Kim Krebs; Sergey Popov

2002-01-01

330

Photophysiological acclimation of Phaeocystis antarctica Karsten under light limitation  

Microsoft Academic Search

Primary production models and pigment algorithms for remote optical systems including satellites, moorings, or drifters depend on an improved understanding of the relationship between spectral light absorption, pigments, and photosynthesis for species of phytoplankton that are widespread and numerically abundant. Cultures of colonial Phaeocystis antarctica, a prymnesiophyte that can dominate the phytoplankton community in the Southern Ocean, were grown under

Tiffany A. Moisan; B. Greg Mitchell

1999-01-01

331

Weather and forecasting at Wilkins ice runway, Antarctica  

Microsoft Academic Search

Aviation forecasts for Wilkins ice runway in East Antarctica are developed within the conceptual framework of flow against a single dome shaped hill. Forecast challenges include the sudden onset of blizzards associated with the formation of an internal gravity wave; frontal weather; transient wake vortices and mesoscale lows; temperature limitations on runway use; and snow and fog events. These key

Scott Carpentier

2010-01-01

332

Are lichens active under snow in continental Antarctica?  

Microsoft Academic Search

Photosynthetic activity, detected as chlorophyll a fluorescence, was measured for lichens under undisturbed snow in continental Antarctica using fibre optics. The fibre optics had been buried by winter snowfall after being put in place the previous year under snow-free conditions. The fibre optics were fixed in place using specially designed holding devices so that the fibre ends were in close

Stefan Pannewitz; Mark Schlensog; T. G. Allan Green; Leopoldo G. Sancho; Burkhard Schroeter

2003-01-01

333

Is the vegetation of continental Antarctica predominantly aquatic?  

Microsoft Academic Search

WE have suggested1 that Antarctic lakes offer a more favourable physical environment to certain species of moss than the surrounding land. We now present evidence in support of the wider thesis that in certain areas of Antarctica most of the plant biomass occurs in aquatic habitats. In the austral summer 1973-74 we found more mosses and algae growing aquatically than

J. J. Light; R. B. Heywood

1975-01-01

334

Araucariaceae macrofossil record from South America and Antarctica  

Microsoft Academic Search

Araucariaceae fossils are abundant in Patagonia and on Seymour (Marambio) and King George (25 de Mayo) islands, Antarctica. Araucariacean macrofossil suites are represented by records of 121 woods, leaves, ovuliferous scales, cones, one seed and seedlings, many of them placed in 50 formalized morphospecies. Although Araucariaceae fossil pollen is known since the Triassic, the oldest reliable macrofossil records in South

Carolina Panti; Roberto R. Pujana; María C. Zamaloa; Edgardo J. Romero

2011-01-01

335

Araucariaceae macrofossil record from South America and Antarctica  

Microsoft Academic Search

Araucariaceae fossils are abundant in Patagonia and on Seymour (Marambio) and King George (25 de Mayo) islands, Antarctica. Araucariacean macrofossil suites are represented by records of 121 woods, leaves, ovuliferous scales, cones, one seed and seedlings, many of them placed in 50 formalized morphospecies. Although Araucariaceae fossil pollen is known since the Triassic, the oldest reliable macrofossil records in South

Carolina Panti; Roberto R. Pujana; María C. Zamaloa; Edgardo J. Romero

2012-01-01

336

Trace metal concentrations of surface snow from Ingrid Christensen Coast, East Antarctica--spatial variability and possible anthropogenic contributions.  

PubMed

To investigate the distribution and source pathways of environmentally critical trace metals in coastal Antarctica, trace elemental concentrations were analyzed in 36 surface snow samples along a coast to inland transect in the Ingrid Christensen Coast of East Antarctica. The samples were collected and analyzed using the clean protocols and an inductively coupled plasma mass spectrometer. Within the coastal ice-free and ice-covered region, marine elements (Na, Ca, Mg, K, Li, and Sr) revealed enhanced concentrations as compared with inland sites. Along with the sea-salt elements, the coastal ice-free sites were also characterized by enhanced concentrations of Al, Fe, Mn, V, Cr, and Zn. The crustal enrichment factors (Efc) confirm a dominant crustal source for Fe and Al and a significant source for Cr, V, Co, and Ba, which clearly reflects the influence of petrological characteristics of the Larsemann Hills on the trace elemental composition of surface snow. The Efc of elements revealed that Zn, Cu, Mo, Cd, As, Se, Sb, and Pb are highly enriched compared with the known natural sources, suggesting an anthropogenic origin for these elements. Evaluation of the contributions to surface snow from the different sources suggests that while contribution from natural sources is relatively significant, local contamination from the increasing research station and logistic activities within the proximity of study area cannot be ignored. PMID:22791020

Thamban, Meloth; Thakur, Roseline C

2012-07-12

337

Variability of 10Be and ?18O in snow pits from Greenland and a surface traverse from Antarctica  

NASA Astrophysics Data System (ADS)

To examine temporal variability of 10Be in glacial ice, we sampled snow to a depth of 160 cm at the NEEM (North Greenland Eemian Ice Drilling) drilling site in Greenland. The samples span three years between the summers of 2006 and 2009. At the same time, spatial variability of 10Be in glacial ice was explored through collection of the upper ˜5 cm of surface snow in Antarctica during part of the Swedish-Japanese traverse from Svea to Syowa station during the austral summer in 2007-2008. The results of the Greenlandic 10Be snow suggested variable concentrations that apparently do not clearly reflect the seasonal change as indicated by the ?18O data. The 10Be concentration variability most likely reflects also effects of aerosol loading and deposition pathways, possibly in combination with post-depositional processes.The Antarctic traverse data expose a negative correlation between 10Be and ?18O, while there are weaker but still significant correlations to altitude and distance to the coast (approximated by the distance to the 70th latitude). These relationships indicate that geographical factors, mainly the proximity to the coast, may strongly affect 10Be concentrations in snow in Queen Maud Land, Antarctica.

Berggren, A.-M.; Aldahan, A.; Possnert, G.; Hansson, M.; Steen-Larsen, H. C.; Sturevik Storm, A.; Mörth, C.-M.; Murad, A.

2013-01-01

338

Microbial Energetics Beneath the Taylor Glacier, Antarctica  

NASA Astrophysics Data System (ADS)

Subglacial microbiology is controlled by glacier hydrology, bedrock lithology, and the preglacial ecosystem. These factors can all affect metabolic function by influencing electron acceptor and donor availability in the subglacial setting leaving biogeochemical signatures that can be used to determine ecosystem processes. Blood Falls, an iron-rich, episodic subglacial outflow from the Taylor Glacier in the McMurdo Dry Valleys Antarctica provides an example of how microbial community structure and function can provide insight into subglacial hydrology. This subglacial outflow contains cryoconcentrated, Pliocene-age seawater salts that pooled in the upper Taylor Valley and was subsequently covered by the advance of the Taylor Glacier. Biogeochemical measurements, culture-based techniques, and genomic analysis were used to characterize microbes and chemistry associated with the subglacial outflow. The isotopic composition of important geochemical substrates (i.e., ?34Ssulfate, ?33Ssulfate, ?18Osulfate, ?18Owater, ?14SDIC) were also measured to provide more detail on subglacial microbial energetics. Typically, subglacial systems, when driven to anoxia by the hydrolysis of organic matter, will follow a continuum of redox chemistries utilizing electron acceptors with decreasing reduction potential (e.g., Fe (III), sulfate, CO2). Our data provide no evidence for sulfate reduction below the Taylor Glacier despite high dissolved organic carbon (450 ?M C) and measurable metabolic activity. We contend that, in the case of the Taylor Glacier, the in situ bioenergetic reduction potential has been 'short-circuited' at Fe(III)-reduction and excludes sulfate reduction and methanogenesis. Given the length of time that this marine system has been isolated from phototrophic production (~2 Mya) the ability to degrade and consume increasingly recalcitrant organic carbon is likely an important component to the observed redox chemistry. Our work indicates that glacier hydrology imparts strong feedbacks on the availability of oxygen as an electron acceptor and may be a robust regulator of the in situ metabolism. This biogeochemical regulation in turn affects the chemical nature of subglacial efflux. Blood Falls demonstrates that measurements of geochemistry and microbial diversity can support models of subglacial hydrology.

Mikucki, J. A.; Turchyn, A. V.; Farquhar, J.; Priscu, J. C.; Schrag, D. P.; Pearson, A.

2007-12-01

339

Space Station Technology Summary.  

National Technical Information Service (NTIS)

The completion of the Space Station Propulsion Advanced Technology Programs established an in-depth data base for the baseline gaseous oxygen/gaseous hydrogen thruster, the waste gas resistojet, and the associated system operations. These efforts included...

R. Iacabucci S. Evans G. Briley R. A. Delventhal E. Braunscheidel

1989-01-01

340

Telerobot for Space Station.  

National Technical Information Service (NTIS)

The Flight Telerobotic Servicer (FTS), a multiple arm dexterous manipulation system, will aid in the assembly, maintenance, and servicing of the space station. Fundamental ideas and basic conceptual designs for a shuttle-based telerobot system have been p...

L. M. Jenkins

1987-01-01

341

Northern Research Station  

Treesearch

... carbon dioxide (CO2) and tropospheric O3 concentrations on fungal communities in ... Keywords: elevated carbon dioxide, elevated ozone, enzyme activities, ... Check the Northern Research Station web site to request a printed copy of this ...

342

Pavlof Volcano From Station  

NASA Website

Astronauts aboard the International Space Station (ISS) photographed this striking view of Pavlof Volcano on May 18, 2013. The oblique perspective from the ISS reveals the three dimensional structure of the ash plume, which is often obscured by the ...

343

Earth orbiting stations  

Microsoft Academic Search

The earth-orbiting station has evolved through Salyut, Skylab, and the Apollo-Soyuz project. The Shuttle combined with Spacelab will permit low-earth-orbit flights of up to 30 days. Later manned and automated free-flying Spacelabs will extend stay-times to 60 days. Bigger space stations housing 6-12 crewmen for up to six months could be built up from modules carried into orbit. Future space

D. W. Patterson; J. W. Gurr; G. V. Butler

1975-01-01

344

Backyard Weather Stations  

NSDL National Science Digital Library

Learn how to build your own backyard weather station with complete directions provided by FamilyEducation.com's Web site, Backyard Weather Stations. The site shows exactly what you'll need and how to build the necessary components (e.g., rain gauge and barometer), as well as how to keep records of the data collected. Parents and teachers will enjoy watching the kids "learn the basics of scientific observation and record-keeping while satisfying their natural curiosity about weather."

Randall, Dennis.

345

Small transportable earth station  

NASA Astrophysics Data System (ADS)

This paper describes design and performance of C band (6/4 GHz) and K band (30/20 GHz) small transportable earth station for domestic satellite communication. These stations consist of three units, an antenna and two containers. Transmitter and receiver equipments are mounted in one container. Terminal equipment and power generator are mounted in the other container, thus enabling transportation by truck or helicopter. System performances are confirmed by experiments using Japanese Medium Capacity Communication Satellite for Experimental Purposes.

Egami, S.; Nara, T.; Kaitsuka, T.; Okamoto, T.

1980-08-01

346

All-year-round aerosol chemical composition at Dome C, Antarctica  

NASA Astrophysics Data System (ADS)

Since 2005, continuous, all-year-round aerosol sampling was carried out at Dome C (Central East Antarctica, 3233 m a.s.l., about 1100 km far from the coastline), in the framework of "Station Concordia" project, an Italian PNRA - French IPEV joint program. Size-segregated aerosol samples were collected in summer and winter periods by using different low- and medium-volume systems, including pre-selected cut-off samplers (with PM10, PM2.5 and PM1 cut-off heads) and multi-stage (Andersen 8-stage and Dekati 4-stage) impactors. Sampling resolution and volumes ranged from 1 day to 1 month and from 2.3 to 12 m3/h, respectively. Aerosol study at Dome C is expected improving our knowledge on present-day source intensity, transport efficiency and pathways (including stratosphere-troposphere interchanges) of particles reaching internal sites of Antarctica. Besides, more detailed information on atmosphere-snow interactions, including depositional and post-depositional processes, as well as the effect of sublimation/condensation processes on snow surface, will be used for improving the reconstruction of past atmosphere composition from ice core chemical stratigraphies (EPICA Dome C ice core). Here we report major results from the chemical composition of the Antarctic background aerosol reaching Dome C, pointing out the seasonal pattern and the temporal trend of some ionic components used as tracers of sea spray, marine biogenic and crustal emissions. Oxidised sulfur compounds are assumed to affect the climate system by influencing the Earth's radiative budget, both directly (solar light scattering) and indirectly (acting as cloud condensation nuclei). Among these compounds, methanesulphonic acid (MSA) and H2SO4 (arising from the atmospheric oxidation of phytoplanktonic dimethylsulphide - DMS), are considered the best tracers of marine productivity. Their use as reliable markers of oceanic biogenic emissions is hindered by poorly known mechanisms (temperature and photochemistry induced) controlling the MSA-H2SO4 ratio from DMS. Since, in summer, DMS in route toward central Antarctica is subjected to larger atmospheric concentrations of OH (and/or BrO) radical, lower temperatures and lower humidity, all conditions promoting the preferential H2SO4 formation, non-sea-salt sulphate is assumed to be the most reliable biogenic marker at Dome C. A further insight from ice-core stratigraphies is concerning the sea salt sodium (ssNa) content in snow precipitation as a reliable marker of sea-ice extent, via frost-flower formation at the pack-ice seasonal growth. This interpretation faces with the classical view that consider higher sea-spray production as caused by an increase in zonal wind intensity. Sea spray originated from frost flowers can be distinguished from sea spray coming from bulk sea-water by the lower sulphate/sodium ratio (caused by mirabilite - Na2SO4 10H20 - precipitation occurring when sea-ice temperature falls below -8°C). High resolution aerosol measurement can allow to identify different sea-spray sources and quantify frost flowers contribution to the annual ssNa budget. Finally, dust recorded in ice cores can be used as a valuable proxy for changes in hydrological cycles in the dust source areas and transport processes (pathways and scavenging). The geochemical characterization of dust in the present-day aerosol, compared with chemical composition of soils collected in South America and Australia, allows identifying the major dust source area (South America) and reconstructing pathways of atmospheric circulation. South America role in feeding dust aerosol at Dome C was supported also by comparing aerosol composition with satellite observations (dust plumes on the source sites) and back-trajectory analysis (air masses reaching Antarctica) during massive dust-storm events.

Udisti, Roberto; Becagli, Silvia; Frosini, Daniele; Galli, Gaia; Ghedini, Costanza; Rugi, Francesco; Severi, Mirko; Traversi, Rita

2010-05-01

347

Shoring pumping station excavation  

SciTech Connect

The city of San Mateo, Calif., operates three 12- to 50-year old wastewater pumping stations on a 24-m (80-ft) wide lot located in a residential area near San Francisco Bay. Because the aging stations have difficulty pumping peak 2.19-m{sup 3}/s (50-mgd) wet-weather flows and have structural and maintenance problems, a new 2.62-m{sup 3}/s (60-mgd) station was proposed - the Dale Avenue Pumping Station - to replace the existing ones. To prevent potential damage to adjacent homes, the new station was originally conceived as a circular caisson type; however, a geotechnical investigation recommended against this type of structure because the stiff soils could make sinking the structure difficult. This prompted an investigation of possible shoring methods for the proposed structure. Several shoring systems were investigated, including steel sheeting, soldier beams and lagging, tieback systems, open excavation, and others; however, each had disadvantages that prevented its use. Because these conventional techniques were unacceptable, attention was turned to using deep soil mixing (DSM) to create a diaphragm wall around the area to be excavated before constructing the pumping station. Although this method has been used extensively in Japan since 1983, the Dale Avenue Pumping Station would be the technology's first US application. The technology's anticipated advantages were its impermeability, its fast and efficient installation that did not require tiebacks under existing homes, its adaptability to subsurface conditions ranging from soft ground to stiff clay to gravels, and its lack of pile-driving requirements that would cause high vibration levels during installation.

Glover, J.B.; Reardon, D.J. (HDR Engineering in El Dorado Hills, CA (United States))

1991-11-01

348

Ecological role for pteroenone, a novel antifeedant from the conspicuous antarctic pteropod Clione antarctica (Gymnosomata: Gastropoda)  

Microsoft Academic Search

Dense populations of the antarctic pteropod Clione antarctica (Smith) offer a rich source of potential nutrients and energy to planktivorous predators. Nonetheless, antarctic fish do not prey on C. antarctica. Employing flash and high-pressure liquid chromatographic techniques, a linear ß-hydroxyketone, pteroenone (C14H24O2) was isolated from whole tissues of C. antarctica. When embedded in alginate food pellets at ecologically relevant concentrations,

P. J. Bryan; W. Y. Yoshida; J. B. McClintock; B. J. Baker

1995-01-01

349

Timber transported to Antarctica: a potential and undesirable carrier for alien fungi and insects  

Microsoft Academic Search

Antarctica’s severe climate and its geographical isolation are the factors that hinder the arrival of non-native species by\\u000a natural means. However, the movement of people and cargo associated with national scientific programs and tourism render Antarctica\\u000a much more accessible to exotic organisms. Both the transport routes and carriers are varied. The wide range of uses to which\\u000a timber is put

Piotr Osyczka; Piotr Mleczko; Dariusz Karasi?ski; Andrzej Chlebicki

350

A combined observational and modeling approach to study modern dust transport from the Patagonia desert to East Antarctica  

NASA Astrophysics Data System (ADS)

The understanding of present atmospheric transport processes from Southern Hemisphere (SH) landmasses to Antarctica can improve the interpretation of stratigraphic data in Antarctic ice cores. In addition, long range transport can deliver key nutrients normally not available to marine ecosystems in the Southern Ocean and may trigger or enhance primary productivity. However, there is a dearth of observational based studies of dust transport in the SH. This work aims to improve current understanding of dust transport in the SH by showing a characterization of two dust events originating in the Patagonia desert (south end of South America). The approach is based on a combined and complementary use of satellite retrievals (detectors MISR, MODIS, GLAS, POLDER, OMI), transport model simulation (HYSPLIT) and surface observations near the sources and aerosol measurements in Antarctica (Neumayer and Concordia sites). Satellite imagery and visibility observations confirm dust emission in a stretch of dry lakes along the coast of the Tierra del Fuego (TdF) island (~54° S) and from the shores of the Colihue Huapi lake in Central Patagonia (~46° S) in February 2005. Model simulations initialized by these observations reproduce the timing of an observed increase in dust concentration at the Concordia Station and some of the observed increases in atmospheric aerosol absorption (here used as a dust proxy) in the Neumayer station. The TdF sources were the largest contributors of dust at both sites. The transit times from TdF to the Neumayer and Concordia sites are 6-7 and 9-10 days respectively. Lidar observations and model outputs coincide in placing most of the dust cloud in the boundary layer and suggest significant deposition over the ocean immediately downwind. Boundary layer dust was detected as far as 1800 km from the source and ˜ 800 km north of the South Georgia Island over the central sub-Antarctic Atlantic Ocean. Although the analysis suggests the presence of dust at ~1500 km SW of South Africa five days after, the limited capabilities of existing satellite platforms to differentiate between aerosol types do not permit a definitive conclusion. In addition, the model simulations show dust lifting to the free troposphere as it travels south but it could not be confirmed by the satellite observations due to cloudiness. This work demonstrates that complementary information from existing transport models, satellite and surface data can yield a consistent picture of the dust transport from the Patagonia desert to Antarctica. It also illustrates the limitation of using any of these approaches individually to characterize the transport of dust in a heavily cloudy area.

Gassó, S.; Stein, A.; Marino, F.; Castellano, E.; Udisti, R.; Ceratto, J.

2010-05-01

351

A combined observational and modeling approach to study modern dust transport from the Patagonia desert to East Antarctica  

NASA Astrophysics Data System (ADS)

The understanding of present atmospheric transport processes from Southern Hemisphere (SH) landmasses to Antarctica can improve the interpretation of stratigraphic data in Antarctic ice cores. In addition, long range transport can deliver key nutrients normally not available to marine ecosystems in the Southern Ocean and may trigger or enhance primary productivity. However, there is a dearth of observational based studies of dust transport in the SH. This work aims to improve current understanding of dust transport in the SH by showing a characterization of two dust events originating in the Patagonia desert (south end of South America). The approach is based on a combined and complementary use of satellite retrievals (detectors MISR, MODIS, GLAS, POLDER, OMI), transport model simulation (HYSPLIT) and surface observations near the sources and aerosol measurements in Antarctica (Neumayer and Concordia sites). Satellite imagery and visibility observations confirm dust emission in a stretch of dry lakes along the coast of the Tierra del Fuego (TdF) island (~54° S) and from the shores of the Colihue Huapi lake in Central Patagonia (~46° S) in February 2005. Model simulations initialized by these observations reproduce the timing of an observed increase in dust concentration at the Concordia Station and some of the observed increases in atmospheric aerosol absorption (here used as a dust proxy) in the Neumayer station. The TdF sources were the largest contributors of dust at both sites. The transit times from TdF to the Neumayer and Concordia sites are 6-7 and 9-10 days respectively. Lidar observations and model outputs coincide in placing most of the dust cloud in the boundary layer and suggest significant deposition over the ocean immediately downwind. Boundary layer dust was detected as far as 1800 km from the source and ~800 km north of the South Georgia Island over the central sub-Antarctic Atlantic Ocean. Although the analysis suggests the presence of dust at ~1500 km SW of South Africa five days after, the limited capabilities of existing satellite platforms to differentiate between aerosol types do not permit a definitive conclusion. In addition, the model simulations show dust lifting to the free troposphere as it travels south but it could not be confirmed by the satellite observations due to cloudiness. This work demonstrates that complementary information from existing transport models, satellite and surface data can yield a consistent picture of the dust transport from the Patagonia desert to Antarctica. It also illustrates the limitation of using any of these approaches individually to characterize the transport of dust in a heavily cloudy area.

Gassó, S.; Stein, A.; Marino, F.; Castellano, E.; Udisti, R.; Ceratto, J.

2010-09-01

352

Terminal and Main Station Functions  

Microsoft Academic Search

There are three types of main stations associated with the L5 system. Power feed main stations provide the dc power required by the line repeaters. Switching power feed main stations add the automatic line protection switching equipment for the L5 system. Terminal main stations provide the equipment for multiplex and related functions. This equipment includes the jumbogroup multiplex (JMX), which

R. Maurer

1974-01-01

353

ECC (Electrochemical Concentration Cell) Ozonesonde Observations at Mirny, Antarctica, during 1988.  

National Technical Information Service (NTIS)

Atmospheric ozone vertical distributions, air temperatures, and wind speed and direction data are presented for 40 balloon electrochemical concentration cell ozone soundings made at Mirny, Antarctica, in 1988.

W. D. Komhyr J. A. Lathrop V. N. Arbuzova V. U. Khattatov P. G. Nureyev

1989-01-01

354

Another bipolar deep-sea anemone: new species of Iosactis (Actiniaria, Endomyaria) from Antarctica  

NASA Astrophysics Data System (ADS)

A new species of deep-sea burrowing sea anemone is described and illustrated from Antarctica. Iosactis antarctica sp. nov. is characterised by easily deciduous tentacles with sphincters in the base, smooth column, endodermal marginal sphincter, same mesenteries proximally and distally, 24 perfect mesenteries regularly arranged, diffuse retractor musculature and basilar muscles well developed. Iosactis antarctica sp. nov. is the second species of the deep-sea abyssal genus Iosactis; it differs from I. vagabunda in internal anatomy, cnidae and geographic distribution. The description of I. antarctica sp. nov. provides the opportunity to revaluate the morphology of the proximal end of this genus.

Rodríguez, Estefanía

2012-06-01

355

UMTS Network Stations  

NASA Astrophysics Data System (ADS)

The weakness of small island electrical grids implies a handicap for the electrical generation with renewable energy sources. With the intention of maximizing the installation of photovoltaic generators in the Canary Islands, arises the need to develop a solar forecasting system that allows knowing in advance the amount of PV generated electricity that will be going into the grid, from the installed PV power plants installed in the island. The forecasting tools need to get feedback from real weather data in "real time" from remote weather stations. Nevertheless, the transference of this data to the calculation computer servers is very complicated with the old point to point telecommunication systems that, neither allow the transfer of data from several remote weather stations simultaneously nor high frequency of sampling of weather parameters due to slowness of the connection. This one project has developed a telecommunications infrastructure that allows sensorizadas remote stations, to send data of its sensors, once every minute and simultaneously, to the calculation server running the solar forecasting numerical models. For it, the Canary Islands Institute of Technology has added a sophisticated communications network to its 30 weather stations measuring irradiation at strategic sites, areas with high penetration of photovoltaic generation or that have potential to host in the future photovoltaic power plants connected to the grid. In each one of the stations, irradiance and temperature measurement instruments have been installed, over inclined silicon cell, global radiation on horizontal surface and room temperature. Mobile telephone devices have been installed and programmed in each one of the weather stations, which allow the transfer of their data taking advantage of the UMTS service offered by the local telephone operator. Every minute the computer server running the numerical weather forecasting models receives data inputs from 120 instruments distributed over the 30 radiometric stations. As a the result, currently it exist a stable, flexible, safe and economic infrastructure of radiometric stations and telecommunications that allows, on the one hand, to have data in real time from all 30 remote weather stations, and on the other hand allows to communicate with them in order to reprogram them and to carry out maintenance works.

Hernandez, C.

2010-09-01

356

Records of climatic changes and volcanic events in an ice core from Central Dronning Maud Land (East Antarctica) during the past century  

NASA Astrophysics Data System (ADS)

The depth profiles of electrical conductance, ?18O,210Pb and cosmogenic radio isotopes10Be and36Cl have been measured in a 30 m ice core from east Antarctica near the Indian station, Dakshin Gangotri. Using210Pb and ?18O, the mean annual accumulation rates have been calculated to be 20 and 21 cm of ice equivalent per year during the past ˜ 150 years. Using these acumulation rates, the volcanic event that occurred in 1815 AD, has been identified based on electrical conductance measurements. Based on ?18O measurements, the mean annual surface air temperatures (MASAT) data observed during the last 150 years indicates that the beginning of the 19th century was cooler by about 2‡ C than the recent past and the middle of 18th century. The fallout of cosmogenic radio isotope10Be compares reasonably well with those obtained on other stations (73‡ S to 90‡ S) from Antarctica and higher latitudes beyond 77‡N. The fallout of36Cl calculated based on the present work agrees well with the mean global production rate estimated earlier by Lal and Peters (1967). The bomb pulse of36Cl observed in Greenland is not observed in the present studies - a result which is puzzling and needs to be studied on neighbouring ice cores from the same region.

Nijampurkar, V. N.; Rao, D. K.; Clausen, H. B.; Kaul, M. K.; Chaturvedi, A.

2002-03-01

357

Let's Talk with Donal Manahan about Antarctica's Early Explorers  

NSDL National Science Digital Library

At this site students will discover that the first time Manahan walked into Scott's primitive 1902 hut, still sitting out on the Antarctic ice, he couldn't help but see how similar their work was despite their very different base camps. This in-depth profile of a marine biologist takes a look at the first explorers of the Antarctic and the challenges they faced. In the question and answer profile, Donal Manahan answers more than 15 questions pertaining to early theories were about what Antarctica was like, how the early explorers communicated with the outside world, why it took so long to find Antarctica, and when huskies were last used. In addition, he tells whom he most admires among the Antarctic explorers and explains the problems they encountered along the way.

358

Synchronous climate changes in antarctica and the north atlantic  

PubMed

Central Greenland ice cores provide evidence of abrupt changes in climate over the past 100,000 years. Many of these changes have also been identified in sedimentary and geochemical signatures in deep-sea sediment cores from the North Atlantic, confirming the link between millennial-scale climate variability and ocean thermohaline circulation. It is shown here that two of the most prominent North Atlantic events-the rapid warming that marks the end of the last glacial period and the Bolling/Allerod-Younger Dryas oscillation-are also recorded in an ice core from Taylor Dome, in the western Ross Sea sector of Antarctica. This result contrasts with evidence from ice cores in other regions of Antarctica, which show an asynchronous response between the Northern and Southern Hemispheres. PMID:9756484

Steig; Brook; White; Sucher; Bender; Lehman; Morse; Waddington; Clow

1998-10-01

359

Arthropod intermediate hosts of Abbreviata antarctica (Nematoda: Physalopteridae) in Australia.  

PubMed

This study examines potential arthropod intermediate hosts for the nematode Abbreviata antarctica. Five species of arthropod (tropical native cricket Teleogryllus oceanicus; native roach Drymoplaneta communis; native termite Nasutitermes exitiosus; and 2 introduced species, the East African roach Naupheta cinerea and the Asian cricket Acheta domesticus) were fed feces from a skink, Tiliqua rugosa, containing embryonated eggs of A. antarctica . The insects were dissected at 4 intervals (1 day, 4 days, 8-16 days, and 25-26 days). Viable third-stage larvae were recovered from cysts on the external wall of the midgut and hindgut of 62.5% nymphal and adult T. oceanicus crickets at 25-26 days post-infection and from a single nymphal A. domesticus cricket. No roaches contained eggs or first-stage larvae after 48 hr, and neither eggs nor larvae were found in termites. PMID:23360383

King, C; Jones, H I; Tay, Chin Yen

2013-01-29

360

Topographic and hydrological controls on Subglacial Lake Ellsworth, West Antarctica  

NASA Astrophysics Data System (ADS)

Subglacial Lake Ellsworth (SLE) was identified using reconnaissance data collected in the 1970s, here we present more detailed surveys. SLE lies beneath 3.2 km of ice in a subglacial valley in West Antarctica. It has an area of only ~18 km2, is dissimilar to the large tectonically-controlled lakes beneath East Antarctica and is a strong candidate for in situ exploration. Our analysis indicates that the ice above SLE is floating on a fluid whose density is 950-1013 kg m-3. This could indicate freshwater, but certainly precludes seawater, or high salt, acid, or clathrate content. The water in the lake is unlikely to be produced solely by local melt; it is more likely delivered via subglacial drainage. Our surveys show no identifiable hydrological barrier to outflow, meaning SLE is effectively full; new water entering the lake is likely balanced by outflow, which would drain into another lake that we have also identified.

Vaughan, David G.; Rivera, Andrés; Woodward, John; Corr, Hugh F. J.; Wendt, Jens; Zamora, Rodrigo

2007-09-01

361

Navigation in Antarctica Today: The Global Positioning System  

NSDL National Science Digital Library

After researching how the Global Positioning System is used in Antarctica and across the globe, students learn how GPS works. Throughout this weeklong activity, students collect their findings in a portfolio. The comprehensive curriculum materials contain teacher tools, which include individually downloadable readings, detailed daily breakdowns of tasks, teacher strategies for using the activities, a portfolio grading sheet, a project rubric sheet, and additional readings. Students investigate the use of the Global Positioning System (GPS)in Antarctica and across the globe. They conduct research on the Web to understand how and why GPS is used today. Students also complete a hands-on activity that is based on spatial principles similar to those used by GPS; they learn how GPS works by doing on paper the work of GPS satellites in space.

362

ASTER Satellite Imagery of Antarctica: a new tool for Glaciology  

NASA Astrophysics Data System (ADS)

Satellite imagery is well suited for studying remote regions such as Antarctica. Until relatively recently, however, the availability and coverage of high-resolution imagery (pixel size < 30 m) over Antarctica have been rather limited. This situation has improved with the success of the Radarsat-1 and Landsat-7 missions. The successful launch of Terra provides another opportunity to collect satellite imagery over one of Earth's least explored regions. ASTER data combine fine spatial resolution (15 m ground resolution for VNIR bands) and good radiometric range (14 bands) suitable for several glaciological applications. Image acquisition extends as far south as 85 degrees so that most of the major ice streams and large outlet glaciers can be studied. Among the glaciological applications of ASTER imagery are mapping active and relict flow features, determining ice velocities, and tracking changes in ice shelf extent. This work is a component of GLIMS (Global Ice Measurement from Space).

Hamilton, G. S.

2001-05-01

363

Temporal dynamics of particulate matter fluxes and sediment community response in Port Foster, Deception Island, Antarctica  

NASA Astrophysics Data System (ADS)

Time-series particle flux and seasonal sediment community oxygen consumption (SCOC) were measured in Port Foster (160 m water depth), Deception Island, Antarctica, beginning in March 1999 and continuing through November 2000. Sediment traps were moored at 50 and 20 m above bottom and collected sedimenting material for contiguous periods of 10 to 18.3 days. Fluxes of material increased in mid-winter of 1999 and 2000 but were more notable in 1999. Fluxes were higher in the deeper sediment trap and there was an inverse relationship between mass flux and % organic carbon and particulate total nitrogen. A piston-operated grab respirometer was deployed at 160 m depth for 35-60 h in November 1999, and in February, May/June, and November 2000, to measure SCOC and recover the sediment for organic carbon, nitrogen and pigment composition. SCOC, as an estimate of sediment community carbon demand, exceeded the organic carbon flux to the seafloor (supply), and alternative sources of organic carbon input to the benthos are discussed. Highest SCOC occurred in the austral summer during a particle-flux sampling hiatus in the summer of 2000. Fluxes were positively correlated with local wind speed measured at a terrestrial station positioned on a hill overlooking Port Foster. There was also a positive correlation between the particulate matter fluxes and the ratio of chlorophyll a to phaeopigments, an indicator of the "freshness" of material entering the sediment trap at 20 mab.

Baldwin, R. J.; Smith, K. L.

2003-06-01

364

Aeolian flux of biotic and abiotic material in Taylor Valley, Antarctica  

NASA Astrophysics Data System (ADS)

We studied patterns and mechanisms controlling wind-driven flux of soils and associated organic matter in Taylor Valley, Antarctica over a 10-year period using passive aeolian traps and dynamic mass erosion particle counters. Deployment of the particle counters near meteorological stations allowed us to compare the magnitude of soil flux with data on prevailing wind. Particulate organic C, N and P measurements on transported sediment allowed us to examine connectivity of wind dispersed organic matter among landscape units.Most sediment entrainment occurred within 20 cm of the soil surface during "saltation bursts" that occupied < 3% of the total time within a year. These bursts corresponded to periods of strong föhn winds where wind velocities were ? 20 m s- 1. Sediment movement was highest in the up-valley reaches of Taylor Valley and transport was down-valley towards McMurdo Sound. The general paucity of biological organic matter production throughout the McMurdo Dry Valleys, in concert with low fluvial transport, makes aeolian distribution or organic C, N and P an important factor in the distribution of organic matter throughout this polar desert ecosystem and increases connectivity among the ecosystem components.

Šabacká, Marie; Priscu, John C.; Basagic, Hassan J.; Fountain, Andrew G.; Wall, Diana H.; Virginia, Ross A.; Greenwood, Mark C.

2012-06-01

365

Measurements of positive ions and air-Earth current density at Maitri, Antarctica  

NASA Astrophysics Data System (ADS)

Simultaneous measurements of the small, intermediate and large positive ions and air-Earth current density made at a coastal station, Maitri (70°45'52?S, 11°44'03?E, 130 m above sea level), at Antarctica during January-February 2005, are reported. Although small and large positive ion concentrations do not show any systematic diurnal variations, variations in them are almost similar to each other. On the other hand, variations in intermediate positive ion concentrations are independent of variations in the small/large positive ions and exhibit a diurnal variation which is similar to that in atmospheric temperature on fair weather days with a maximum during the day and minimum during the night hours. No such diurnal variation in intermediate positive ion concentration is observed on cloudy days when variations in them are also similar to those in small/large positive ion concentrations. Magnitude of diurnal variation in intermediate positive ion concentration on fair weather days increases with the lowering of atmospheric temperature in this season. Scavenging of ions by snowfall and trapping of ?-rays from the ground radioactivity by a thin layer of snow on ground is demonstrated from observations. Variations in intermediate positive ion concentration are explained on the basis of the formation of new particles by the photolytic nucleation process.

Siingh, Devendraa; Pant, Vimlesh; Kamra, A. K.

2007-07-01

366

Variations in crustal structure across the transition from West to East Antarctica, Southern Victoria Land  

NASA Astrophysics Data System (ADS)

The crustal structure beneath Ross Island and the Transantarctic Mountains (TAM) in Southern Victoria Land, Antarctica, is inferred using non-linear inversion of receiver functions, derived from teleseismic earthquake data. Intermediate-period waveforms from more than 160 teleseismic earthquakes recorded between January 1994 and January 2000 were used in the analysis. The inversion results confirm a crustal thickness of 19-21 km beneath Ross Island, consistent with previous multichannel seismic work. In addition we observe a crustal thickness of 18-20 km beneath the Ross Sea coastline immediately adjacent to the TAM. Further inland, beneath the TAM, the estimated Moho depths range from 30-33 km (~30 km from the coast) to 36-40 km (~85 km from the coast), deepening away from the coast beneath the TAM. These results are in broad agreement with previous seismic and gravity interpretations. Beneath the TAM a sharp mid-crustal discontinuity is present at 8-14 km depth beneath the eastern-most stations, but absent on the western side of the TAM, indicating a spatial change in the mid-crustal composition.

Bannister, S.; Yu, J.; Leitner, B.; Kennett, B. L. N.

2003-12-01

367

First mesospheric observations using an imaging Doppler interferometer adaptation of the dynasonde at Halley, Antarctica  

NASA Astrophysics Data System (ADS)

The digital ionospheric sounder, or dynasonde, located at the British Antarctic Survey's research station at Halley, Antarctica, has recently been operated as an imaging Doppler interferometer (IDI). The implementation of this mode of operation does not require any changes to the system hardware but involves a specially written sounding configuration and newly designed data analysis software. Using four independent antennas and two receivers, the signals returned from mesospheric altitudes are range-gated and processed using Doppler sorting and spatial interferometry. A three-dimensional (3-D) image of the scattering locations can then be built up for a region stretching to over 30 degrees from the zenith. The sky map locations and Doppler velocities of the individual scattering points are used to fit a 3-D velocity vector representing the motion of the neutral wind in the mesosphere. In this paper the radar hardware, sounding configuration, and data processing are described, and the relative merits of the IDI technique as applied at Halley are discussed. The characteristics of the scattering points are outlined, and initial neutral wind measurements are presented.

Jones, G. O. L.; Charles, K.; Jarvis, M. J.

1997-11-01

368

An Uninhabited Aerial Vehicle (UAV) Concept for Low-Altitude Geophysical Exploration in Antarctica  

NASA Astrophysics Data System (ADS)

A concept for a small, agile UAV platform for conducting geophysical mapping in the IPY and beyond has been explored. We have developed a framework concept for community input and feedback based on a low-cost, autonomous vehicle with onboard high-precision inertial navigation that performs vertical take-off and landing (VTOL). The vehicle we have focused on is the GoldenEye-100, developed by Aurora Flight Sciences Corp. (www.aurora.aero), which can carry a lightweight payload and achieve a range of 300-500 km (roundtrip). The VTOL capability would potentially allow flights to be launched from the helicopter deck of an icebreaker, and would remove the logistical burden of ensuring a hazard-free runway on the ice. Vehicle operations are controlled using a portable ground station. A payload concept has also been developed, indicating that the vehicle could easily carry a lightweight, compact magnetometer, camera and laser altimeter. Instruments developed for space missions exist that would enable a high performance system to be carried within the ~10 kg payload envelope. A gravity measurement system and radar sounder are also considered. A capable UAV platform for geophysical mapping would complement the existing aerial research platforms in Antarctica and has the potential to accelerate the exploration and monitoring of critical but remote areas in a cost-effective manner.

Raymond, C. A.; Behar, A. E.

2004-05-01

369

Long-Term Dosimetry of Solar UV Radiation in Antarctica with Spores of Bacillus subtilis  

PubMed Central

The main objective was to assess the influence of the seasonal stratospheric ozone depletion on the UV climate in Antarctica by using a biological test system. This method is based on the UV sensitivity of a DNA repair-deficient strain of Bacillus subtilis (TKJ 6321). In our field experiment, dried layers of B. subtilis spores on quartz discs were exposed in different seasons in an exposure box open to solar radiation at the German Antarctic Georg von Neumayer Station (70°37?S, 8°22?W). The UV-induced loss of the colony-forming ability was chosen as the biological end point and taken as a measure for the absorbed biologically harmful UV radiation. Inactivation constants were calculated from the resulting dose-response curves. The results of field experiments performed in different seasons indicate a strongly season-dependent trend of the daily UV-B level. Exposures performed at extremely depleted ozone concentrations (October 1990) gave higher biologically harmful UV-B levels than expected from the calculated season-dependent trend, which was determined at normal ozone values. These values were similar to values which were measured during the Antarctic summer, indicating that the depleted ozone column thickness has an extreme influence on the biologically harmful UV climate on ground.

Puskeppeleit, Monika; Quintern, Lothar E.; el Naggar, Saad; Schott, Jobst-Ulrich; Eschweiler, Ute; Horneck, Gerda; Bucker, Horst

1992-01-01

370

High frequence and automatic link establishment (HF and ALE) radio propagation test to Antarctica  

NASA Astrophysics Data System (ADS)

Recent federal/military standards in the area of automatic link establishment (ALE) for HF radios have been developed that coordinate frequency selection between communicating terminals, allowing them to adapt to skywave conditions. This study focused on evaluating the utility of these state-of-the-art radios in the polar environment. A quick-look evaluation of this technology was demonstrated over a radio circuit between Christchurch, New Zealand, and McMurdo Station, Antarctica. This transauroral link, operated by the U.S. Navy for the National Science Foundation, is the primary link for all operational, logistical, and emergency communications for U.S. operations between the Antarctic and the outside world. Daily plots of the measured signal to noise ratio, probability of bit error, and channel quality are presented and analyzed. Because of the initial success of this technology demonstration, additional experiments were designed for deployment in FY 1993 to answer not only operational issues, but also to collect data for further scientific studies and engineering improvements.

Gilles, P. E.; Katan, J. R.; Pease, B. L.

1994-02-01

371

The rates of sea salt sulfatization in the atmosphere and surface snow of inland Antarctica  

NASA Astrophysics Data System (ADS)

Most of the aerosol particles present in the surface snow and ice of inland Antarctica come from primary sea salt (sodium chloride) and marine biological activity (methansulfonic and sulfuric acids). Melted water from surface snow, firn, and Holocene ice contains mainly sodium, chloride, and sulfate ions. Although it is well known that sea salt aerosols react rapidly with sulfuric acid, a process known as sulfatization, it is not known when this process takes place. In this research we undertake to measure the proportion of sea salt aerosols that undergo sulfatization in the atmosphere and surface snow, as opposed to deeper ice, in order to understand the suitability of sea salt aerosols as a proxy for past climates in deep ice cores. We directly measure the sulfatization rates in recently fallen snow (0-4 m in depth) collected at the Dome Fuji station, using X-ray dispersion spectroscopy to determine the constituent elements of soluble particles and computing the molar ratios of sodium chloride and sodium sulfate. We estimate that about 90% of the initial sea salt aerosols sulfatize as they are taken up by precipitation over Dome Fuji or in the snowpack within one year after being deposited on the ice sheet.

Iizuka, Yoshinori; Tsuchimoto, Akira; Hoshina, Yu; Sakurai, Toshimitsu; Hansson, Margareta; Karlin, TorbjöRn; Fujita, Koji; Nakazawa, Fumio; Motoyama, Hideaki; Fujita, Shuji

2012-02-01

372

Weather and forecasting at Wilkins ice runway, Antarctica  

NASA Astrophysics Data System (ADS)

Aviation forecasts for Wilkins ice runway in East Antarctica are developed within the conceptual framework of flow against a single dome shaped hill. Forecast challenges include the sudden onset of blizzards associated with the formation of an internal gravity wave; frontal weather; transient wake vortices and mesoscale lows; temperature limitations on runway use; and snow and fog events. These key weather aspects are presented within the context of synoptic to local scale climatologies and numerical weather prediction models.

Carpentier, Scott

2010-08-01

373

Seasonal cycle of the microbial plankton in Crooked Lake, Antarctica  

Microsoft Academic Search

Changes in the abundance of the components of the microbial plankton between July 1990 and March 1991 in Crooked Lake, one of the largest and deepest freshwater lakes in Antarctica, are described. Chlorophyll a concentration is low (0.2–0.4µg·1-1) and there is no discernable spring increase. The phytoplankton is largely dominated by flagellates. Bacterioplankton exhibits a seasonal pattern of abundance ranging

Johanna Laybourn-Parry; Harvey J. Marchant; Peter E. Brown

1992-01-01

374

Breakup and early seafloor spreading between India and Antarctica  

Microsoft Academic Search

We present a tectonic interpretation of the breakup and early seafloor spreading between India and Antarctica based on improved coverage of potential field and seismic data off the east Antarctic margin between the Gunnerus Ridge and the Bruce Rise. We have identified a series of ENE trending Mesozoic magnetic anomalies from chron M9o (~130.2 Ma) to M2o (~124.1 Ma) in

Carmen Gaina; R. Dietmar Müller; Belinda Brown; Takemi Ishihara; Sergey Ivanov

2007-01-01

375

Submillimeter astrophysics from Antarctica in the ALMA era  

NASA Astrophysics Data System (ADS)

The Atacama Large Millimeter/submillimeter Array (ALMA) is currently being constructed at the 5000 m Chajnantor plateau in the Chilean Andes. ALMA has been designed and is being built to deliver transformational science in the millimeter and submillimeter regime for many years to come. We briefly describe the project status and timeline. We discuss which niches in millimeter/ submillimeter astronomy will remain open for a possible facility in Antarctica.

Testi, L.

376

Cold-tolerant alkane-degrading Rhodococcus species from Antarctica  

Microsoft Academic Search

Bioremediation is a possible mechanism for clean-up of hydrocarbon-contaminated soils in the Antarctic. Microbes indigenous\\u000a to the Antarctic are required that degrade the hydrocarbon contaminants found in the soil, and that are able to survive and\\u000a maintain activity under in situ conditions. Alkane- degrading bacteria previously isolated from oil-contaminated soil from around Scott Base, Antarctica,\\u000a grew on a number of

Asim K. Bej; David Saul; Jackie Aislabie

2000-01-01

377

Isolates of Arthrobacter from the soils of Schirmacher Oasis, Antarctica  

Microsoft Academic Search

Thirteen isolates of bacteria from the soils of Schirmacher Oasis, Antarctica have been identified as members of the genus Arthrobacter. All the isolates exhibited a rod-coccus cycle during growth; were gram positive, catalase positive, non-motile and non-fermentative; did not form endospores; and contained MK-8 (H2) as the major menaquinone. The mole %G + C in DNA of the isolates ranged

S. Shivaji; N. Shyamala Rao; L. Saisree; G. S. N. Reddy; G. Seshu Kumar; P. M. Bhargava

1989-01-01

378

Diversity of Soil Yeasts Isolated from South Victoria Land, Antarctica  

Microsoft Academic Search

Unicellular fungi, commonly referred to as yeasts, were found to be components of the culturable soil fungal population in\\u000a Taylor Valley, Mt. Discovery, Wright Valley, and two mountain peaks of South Victoria Land, Antarctica. Samples were taken\\u000a from sites spanning a diversity of soil habitats that were not directly associated with vertebrate activity. A large proportion\\u000a of yeasts isolated in

L. Connell; R. Redman; S. Craig; G. Scorzetti; M. Iszard; R. Rodriguez

2008-01-01

379

Benthic Faunal Composition along Princess Astrid Coast, East Antarctica  

Microsoft Academic Search

species, representing 9 major benthic faunal groups encountered at 200 m depth off the Princess Astrid coast (Lat. 69°54'S; Long. 12°49'E) in the Eastern Antarctica, are described here. Estimated benthic biomass was 68 gm -2 . Echinoderms (35%) followed by sponges (22%), molluscs (15%), ascidians (8%), coelenterates (5%), crustaceans (5%), bryozoans (4%) and annelids (3%) were the major faunal taxa.

R. A. SREEPADA; V. JAYASREE; A. H. PARULEKAR

380

Late Quaternary Diatom Assemblages from Prydz Bay, Eastern Antarctica  

Microsoft Academic Search

The paleo-depositional environment of inner Prydz Bay, East Antarctica, has been reconstructed for the past 21,320 14C yr B.P., using diatom assemblages and sediment facies from a short, 352-cm-long gravity core. Between 21,320 and 11,650 14C yr B.P., compact tillite and diamicton are present in the core, and diatom frustules are rare to absent. These data suggest that an ice

Fiona Taylor; Andrew McMinn

2002-01-01

381

Paleomagnetic study of Deception Island, South Shetland Islands, Antarctica  

Microsoft Academic Search

A paleomagnetic study was carried out on recent volcanic rocks exposed on Deception Island (63.0°S, 60.6°W), Antarctica. Sampling comprised all stratigraphic units exposed on the island, which include basaltic, andesitic and trachytic lavas, basaltic dykes and pyroclastic flows. Following stepwise thermal and alternating field demagnetization procedures, consistent characteristic remanence directions were determined at 21 sites, using principal-component analysis. The overall

Andrés Baraldo; Augusto E. Rapalini; Harald Böhnel; Mabel Mena

2003-01-01

382

Early Cretaceous Uplift in the Ellsworth Mountains of West Antarctica  

Microsoft Academic Search

Apatite fission-track analysis of samples covering a 4.2-kilometer vertical section from the western flank of Vinson Massif, Antarctica's highest mountain, indicates that the Ellsworth Mountains were uplifted by 4 kilometers or more during the Early Cretaceous following the initial separation of East and West Gondwana and accompanying the opening of the Weddell Sea. Relief of at least 1.8 kilometers has

Paul G. Fitzgerald; Edmund Stump

1991-01-01

383

Observations of cosmic background radiation anisotropy from Antarctica  

SciTech Connect

A ground-based experiment has been carried out in Terra Nova Bay, Antarctica in order to detect anisotropies in cosmic background radiation at an angular scale of 1.3 deg. A 1-m-diameter flux collector and an He-3-cooled bolometric detector sensitive to radiation with a wavelength between 1.86 and 2.34 mm are used. Observations were carried out during the Antarctic summer and are limited by atmospheric emission fluctuations. 13 references.

Dall'oglio, G.; De Bernardis, P.

1988-08-01

384

Why Is Antarctica the Windiest Place on Earth?  

NSDL National Science Digital Library

After examining weather reports to learn for themselves how windy Antarctica can get, students investigate the contributing factors in this week-long unit. Throughout, they collect their findings in a portfolio. The comprehensive curriculum materials contain teacher tools, three activities, Q&A interviews with two Antarctic researchers, and a student handout with guidance for putting together their portfolios and examples of creative final projects.

385

Mineral Chemistry of Volcanic Rocks of South Shetland Archipelago, Antarctica  

Microsoft Academic Search

This study presents the results of mineral chemistry data of Meso-Cenozoic volcanic rocks of Livingston, Robert and Ardley islands (South Shetland Arc, Antarctica). These rocks include basalts and basaltic andesites that exhibit pilotaxitic, intergranular, and intersertal textures. Glomeroporphyritic clusters consist of phenocrysts of plagioclase, augite, and Ti-magnetite or only plagioclase. The rocks are composed of plagioclase, augite, olivine, Ti-magnetite, and

Adriane Machado; Evandro Fernandes de Lima; Farid Chemale; Felipe Marcelo Alexandre; Carlos Augusto Sommer; Ana Maria Graciano Figueiredo; Delia del Pilar Montecinos de Almeida

2008-01-01

386

Performance of some environmental power systems in Antarctica  

Microsoft Academic Search

In the austral summer season of 2007\\/8 we deployed four systems to measure the geo-electric field at three remote locations in Antarctica at 78°S 23°W 1525m, 81°S 22°W 1180m, 75°S 71°W 1560m. The scientific measurements are the Air to Earth current (about 2-6pAm-2), the electric field potential (100-200Vm-1) and the supporting meteorology. Here, however, we concern ourselves with the design

M. C. Rose; D. Maxfield; J. Junyent

2009-01-01

387

Orbital solar electric power stations  

NASA Astrophysics Data System (ADS)

Various aspects of the development of space based solar electric power stations are discussed. Topics discussed include solar energy for the national economy, solar energy in space, a typical space-based solar electric power station, reasons for the low economic efficiency of space based solar electric power stations, the impact of solar electric power stations on the environment, the structural design of a small-scale space based solar electric power station, and the militarization of space.

Narimanov, Ye. A.; Virko, I. G.

1992-01-01

388

Biochemical and microbial features of shallow marine sediments along the Terra Nova Bay (Ross Sea, Antarctica)  

NASA Astrophysics Data System (ADS)

Shallow marine sediments were collected from seven stations (three of which located at Gerlache Inlet, two at Tethys Bay, one at Adelie Cove and one just beneath the Italian Research Base) along the Terra Nova Bay coast (Ross Sea, Antarctica). Their chemical, biochemical and microbiological properties were studied in order to provide further insights in the knowledge of this Antarctic benthic ecosystem. Overall, the organic carbon (OC) represented the major fraction of total carbon (TC) and displayed concentrations similar to or slightly lower than those previously measured in Antarctic bottom sediments. The biopolymeric carbon within OC ranged from 4.1% to 19.9% and showed a wide trophic range (65-834 ?g g -1 d.w.). Proteins (PRT) represented on average the main biochemical class contributing to labile organic carbon, followed by lipids (LIP) and carbohydrates (CHO). The activity of aminopeptidase, ?- D-glucosidase, alkaline phosphatase and esterase was checked, giving the highest values at Tethys Bay and at the deepest water sediments. The principal component analysis, which was computed considering physical, chemical (elemental and biochemical sedimentary composition) and microbiological parameters (including bacterial abundance, ectoenzymatic activities, T-RFs richness and diversity indices), allowed to obtain two main clusters ("Tethys Bay" and "other stations"). Based on data obtained, two representative 16S rRNA clone libraries using samples from Tethys Bay and Gerlache Inlet were constructed. The sequences of 171 clones were compared to those available in public databases to determine their approximate phylogenetic affiliations. Both aerobic and anaerobic bacteria were disclosed, with the majority of them affiliated with the Gamma- and Deltaproteobacteria, Bacteroidetes and Acidobacteria. The occurrence of strictly anaerobic bacteria suggests that sediments might also undergo anoxic conditions that, in turn, could favor the accumulation of PRT in respect to CHO, assuming that fermentation of amino acids is slower than that of sugars from decomposing polysaccharides.

Baldi, Franco; Marchetto, Davide; Pini, Francesco; Fani, Renato; Michaud, Luigi; Lo Giudice, Angelina; Berto, Daniela; Giani, Michele

2010-09-01

389

Factors affecting phytoplankton distribution and production in the Elephant Island area, Antarctica  

SciTech Connect

During the austral summer of four years, 1990 to 1993, studies on phytoplankton were performed in the Elephant Island area as one component of the US Antarctica Marine Living Resources program. In addition to continuous measurements (temperature, salinity, chlorophyll-a, beam attenuation) made on ship's intake water, a profiling CTD-rosette unit was used to obtain water column characteristics (temperature, salinity, chlorophyll-a, attenuation of solar radiation, beam attenuation) from the surface to 750m depth and also water samples from at least 10 depths for chemical and biological analyses. The sampling grid consisted of an average of 70 stations, all of which were occupied two times each year. The Elephant Island area is a transition zone between the rich coastal areas, where phytoplankton can develop dense blooms, and pelagic waters where the phytoplankton biomass is in general very low. A frontal zone was usually found to the north of Elephant Island and over the continental slope, and high phytoplankton biomass was in general associated with this frontal region. Although the location of this frontal system showed seasonal movement in a north-south direction, it seems to be a consistent feature from year to year. There seems to be considerable year-to-year variability in physical (water temperatures and salinity) and phytoplankton characteristics within the study area, in regard to both distributional patterns in surface waters and to profile characteristics in the upper 100m of the water column. With shallow upper mixed layer depths of less than 50 m, phytoplankton can attain relatively high concentrations. Optimum light conditions for growth occurred when the mixed layer was less than 55% of the euphotic zone. As the area around Elephant Island is characterized by relatively strong and frequent winds, the depth of the upper mixed layer at many stations approached the depth of the euphotic zone, with the result that growth of phytoplankton was light limited.

Helbling, E.W.

1993-01-01

390

Isolation and characterization of halotolerant Streptomyces radiopugnans from Antarctica soil.  

PubMed

An actinomycete wild strain PM0626271 (= MTCC 5447), producing novel antibacterial compounds, was isolated from soil collected from Antarctica. The taxonomic status of the isolate was established by polyphasic approach. Scanning electron microscopy observations and the presence of LL-Diaminopimelic acid in the cell wall hydrolysate confirmed the genus Streptomyces. Analysis of 16S rRNA gene sequence showed highest sequence similarity to Streptomyces radiopugnans (99%). The phylogenetic tree constructed using near complete 16S rRNA gene sequences of the isolate and closely related strains revealed that although the isolate fell within the S. radiopugnans gene subclade, it was allocated a different branch in the phylogenetic tree, separating it from the majority of the radiopugnans strains. Similar to type strain, S. radiopugnans R97(T) , the Antarctica isolate displayed thermo tolerance as well as resistance to (60) Co gamma radiation, up to the dose of 15 kGy. However, media and salt tolerance studies revealed that, unlike the type strain, this isolate needed higher salinity for its growth. This is the first report of S. radiopugnans isolated from the Antarctica region. The GenBank/EMBL/DDBJ accession number for the 16S rRNA gene sequence of Streptomyces radiopugnans MTCC 5447 is JQ723477. PMID:23384241

Bhave, S V; Shanbhag, P V; Sonawane, S K; Parab, R R; Mahajan, G B

2013-02-22

391

Radiative Influence of Antarctica on the Polar-Night Vortex.  

NASA Astrophysics Data System (ADS)

Temperatures over the Antarctic plateau are sharply colder than those over its maritime surroundings. The sharp temperature contrast due to Antarctica is conveyed upward through 9.6-m absorption by ozone, which shapes the thermal structure in the stratosphere. The radiative impact of Antarctica on the polar stratosphere is investigated in three-dimensional integrations of the nonlinear primitive equations, coupled to a full radiative-transfer calculation that is performed with and without clouds. Cooling associated with Antarctica depresses radiative-equilibrium temperatures by as much as 10 K. This direct radiative influence emerges clearly at high latitudes of the lowermost stratosphere. It is accompanied elsewhere by temperature changes of opposite sign, which result indirectly through adiabatic warming by the induced residual meridional circulation. Collectively, these influences reinforce the polar-night vortex, shift the jet axis poleward, and intensify downward transport over the polar cap by the residual circulation. In this way, radiative forcing from below contributes significantly to the features that distinguish the Antarctic vortex from the Arctic vortex.

Francis, Gene L.; Salby, Murry L.

2001-05-01

392

The organized Space Station  

NASA Astrophysics Data System (ADS)

Space Station organization designers should consider the onboard stowage system to be an integral part of the environment structured for productive working conditions. In order to achieve this, it is essential to use an efficient inventory control system able to track approximately 50,000 items over a 90-day period, while maintaining peak crew performance. It is noted that a state-of-the-art bar-code inventory management system cannot satisfy all Space Station requirements, such as the location of a critical missing item.

Lew, Leong W.

393

Solar power station  

SciTech Connect

Solar power station with semiconductor solar cells for generating electric power is described, wherein the semiconductor solar cells are provided on a member such as a balloon or a kite which carries the solar cells into the air. The function of the balloon or kite can also be fulfilled by a glider or airship. The solar power station can be operated by allowing the system to ascend at sunrise and descend at sunset or when the wind is going to be too strong in order to avoid any demage.

Wenzel, J.

1982-11-30

394

Whole-Genome Shotgun Sequencing of Rhodococcus erythropolis Strain P27, a Highly Radiation-Resistant Actinomycete from Antarctica.  

PubMed

Here, we report the draft genome sequence of radiation-resistant Rhodococcus erythropolis strain P27, isolated from leaves of Deschampsia antarctica Desv. (Poaceae) in the Admiralty Bay area, Antarctica. PMID:24072865

Gouvêa Taketani, Rodrigo; Domingues Zucchi, Tiago; Soares de Melo, Itamar; Mendes, Rodrigo

2013-09-26

395

Whole-Genome Shotgun Sequencing of Rhodococcus erythropolis Strain P27, a Highly Radiation-Resistant Actinomycete from Antarctica  

PubMed Central

Here, we report the draft genome sequence of radiation-resistant Rhodococcus erythropolis strain P27, isolated from leaves of Deschampsia antarctica Desv. (Poaceae) in the Admiralty Bay area, Antarctica.

Gouvea Taketani, Rodrigo; Domingues Zucchi, Tiago; Soares de Melo, Itamar

2013-01-01

396

The Helium Isotopic Chemistry of Lake Bonney, Taylor Valley, Antarctica: Timing of Late Holocene Climate Change in Antarctica  

Microsoft Academic Search

To better understand the long-term climate history of Antarctica, we studied Lake Bonney in Taylor Valley, Southern Victoria Land (78°S). Helium isotope ratios and He, Ne, Ar and N2 concentration data, obtained from hydrocasts in the East (ELB) and West (WLB) Lobes of Lake Bonney, provided important constraints on the lake’s Holocene evolution. Based on very low concentrations of Ar

Robert J. Poreda; Andrew G. Hunt; W. Berry Lyons; Kathleen A. Welch

2004-01-01

397

The Home Weather Station.  

ERIC Educational Resources Information Center

Described is how an amateur weather observer measures and records temperature and precipitation at a well-equipped, backyard weather station. Directions for building an instrument shelter and a description of the instruments needed for measuring temperature and precipitation are included. (KR)

Steinke, Steven D.

1991-01-01

398

The Home Weather Station.  

ERIC Educational Resources Information Center

|Described is how an amateur weather observer measures and records temperature and precipitation at a well-equipped, backyard weather station. Directions for building an instrument shelter and a description of the instruments needed for measuring temperature and precipitation are included. (KR)|

Steinke, Steven D.

1991-01-01

399

Water Exploration Station  

NSDL National Science Digital Library

In this activity (located on page 3 of the PDF), learners investigate the way water moves and how we can control and direct water. At the Water Exploration Station, learners experiment with various tools like eye droppers, sponges, turkey basters, etc. to move and play with the water. Included in this lesson guide are challenge questions intended to direct the learning.

Museum, Chicago C.

2008-01-01

400

Hydrogen Filling Station  

Microsoft Academic Search

Hydrogen is an environmentally attractive transportation fuel that has the potential to displace fossil fuels. The Freedom CAR and Freedom FUEL initiatives emphasize the importance of hydrogen as a future transportation fuel. Presently, Las Vegas has one hydrogen fueling station powered by natural gas. However, the use of traditional sources of energy to produce hydrogen does not maximize the benefit.

Robert F Boehm; Bruce Sabacky; Everett B Anderson II; David Haberman; Mowafak Al-Hassin; Xiaoming He; Brian Morriseau

2010-01-01

401

Station Model Plot  

NSDL National Science Digital Library

This applet provides a test of decoding station model plots. From the plot, the user must determine the temperature, dew point, wind speed and direction, cloud cover, pressure and pressure change, and current weather. Values can be checked and attempted again.

Ackerman, Steve; Whittaker, Tom

402

Station Crew Celebrates Christmas  

NASA Video Gallery

Aboard the orbiting International Space Station, Expedition 34 Commander Kevin Ford, Russian Flight Engineers Oleg Novitskiy, Evgeny Tarelkin and Roman Romanenko, NASA Flight Engineer Tom Marshburn and Canadian Space Agency Chris Hadfield celebrated Christmas on the orbital laboratory Dec. 25, 2012 through song and downlink messages of cheer for flight controllers on the ground.

Gerald T Wright

2012-12-26

403

Designing a Weather Station  

ERIC Educational Resources Information Center

|The collection and analysis of weather data is crucial to the location of alternate energy systems like solar and wind. This article presents a design challenge that gives students a chance to design a weather station to collect data in advance of a large wind turbine installation. Data analysis is a crucial part of any science or engineering…

Roman, Harry T.

2012-01-01

404

Micro hydroelectric power stations  

Microsoft Academic Search

This book is a concise, comprehensive presentation of all aspects of hydro-power exploitation using micro-power stations. It offers engineers guidance to techniques for assessing the power available from a given stream, designing and building siteworks, selecting the appropriate turbine types for given conditions, and measuring and controlling environmental hazards associated with micro-hydro installations.

L. Monition; L. LeNir; J. Roux

1985-01-01

405

Hydroelectric power station  

Microsoft Academic Search

In a low-head hydroelectric power station, a turbine runner is mounted within the hub of a convergent-divergent draft tube at the base of a dam. At least one turbine is coupled to one or more electric generators housed within a casing which is totally submerged within the upstream pool. The distance from the generator casing to the draft tube intake

Cros

1981-01-01

406

Space Station Commonality Analysis.  

National Technical Information Service (NTIS)

This study was conducted on the basis of a modification to Contract NAS8-36413, Space Station Commonality Analysis, which was initiated in December, 1987 and completed in July, 1988. The objective was to investigate the commonality aspects of subsystems a...

1988-01-01

407

Kiowa Creek Switching Station  

SciTech Connect

The Western Area Power Administration (Western) proposes to construct, operate, and maintain a new Kiowa Creek Switching Station near Orchard in Morgan County, Colorado. Kiowa Creek Switching Station would consist of a fenced area of approximately 300 by 300 feet and contain various electrical equipment typical for a switching station. As part of this new construction, approximately one mile of an existing 115-kilovolt (kV) transmission line will be removed and replaced with a double circuit overhead line. The project will also include a short (one-third mile) realignment of an existing line to permit connection with the new switching station. In accordance with the Council on Environmental Quality (CEQ) regulations for implementing the procedural provisions of the National Environmental Policy Act of 1969 (NEPA), 40 CFR Parts 1500--1508, the Department of Energy (DOE) has determined that an environmental impact statement (EIS) is not required for the proposed project. This determination is based on the information contained in this environmental assessment (EA) prepared by Western. The EA identifies and evaluates the environmental and socioeconomic effects of the proposed action, and concludes that the advance impacts on the human environment resulting from the proposed project would not be significant. 8 refs., 3 figs., 1 tab.

Not Available

1990-03-01

408

SolStation: Saturn  

NSDL National Science Digital Library

This SolStation site provides a detailed and well-illustrated description of the Saturn system, beginning with" Breaking News" and then moving to a description of the planet, the rings, and the moons. The many images and accompanying detailed discussion present a wealth of information. The text is written for someone with a good working understanding of introductory physics.

2008-10-28

409

Space station? statement  

NASA Astrophysics Data System (ADS)

To date much of the Space Station discussion has focused on what it costs, how it will be managed, and its detailed configuration. There's been relatively little discussion of the objectives and requirements it must meet in spite of the fact that our experience has shown the criticallity of establishing well-defined objectives prior to initiating the development phase of such a program.

Meredith, L. H.

410

Tidal station displacements  

Microsoft Academic Search

Theoretical modeling of the station displacements produced by tidal deformations of the Earth due to lunisolar gravitational forces is a necessary part of the analysis of space geodetic data. To attain the accuracies demanded by the precision of the data, a generalized version of the Love number formalism has to be used wherein the classical Love and Shida numbers are

P. M. Mathews; V. Dehant; John M. Gipson

1997-01-01

411

Seismic monitoring at Deception Island volcano (Antarctica): the 2010-2011 survey  

NASA Astrophysics Data System (ADS)

As an example of the recent advances introduced in seismic monitoring of Deception Island volcano (Antarctica) during recent years, we describe the instrumental network deployed during the 2010-2011 survey by the Instituto Andaluz de Geofísica of University of Granada, Spain (IAG-UGR). The period of operation extended from December 19, 2010 to March 5, 2011. We deployed a wireless seismic network composed by four three-component seismic stations. These stations are based on 24-bit SL04 SARA dataloggers sampling at 100 sps. They use a PC with embedded linux and SEISLOG data acquisition software. We use two types of three-component seismometers: short-period Mark L4C with natural frequency of 1 Hz and medium-period Lennartz3D/5s with natural frequency of 0.2 Hz. The network was designed for an optimum spatial coverage of the northern half of Deception, where a magma chamber has been reported. Station locations include the vicinity of the Spanish base "Gabriel de Castilla" (GdC), Obsidianas Beach, a zone near the craters from the 1970 eruptions, and the Chilean Shelter located south of Pendulum Cove. Continuous data from the local seismic network are received in real-time in the base by wifi transmission. We used Ubiquiti Networks Nanostation2 antennas with 2.4 GHz, dual-polarity, 10 dBi gain, and 54 Mbps transmission rate. They have shown a great robustness and speed for real-time applications. To prioritize data acquisition when the battery level is low, we have designed a circuit that allows independent power management for the seismic station and wireless transmission system. The reception antenna located at GdC is connected to a computer running SEISCOMP. This software supports several transmission protocols and manages the visualization and recording of seismic data, including the generation of summary plots to show the seismic activity. These twelve data channels are stored in miniseed format and displayed in real time, which allows for a rapid evaluation of the seismic activity and an efficient seismo-volcanic surveillance. The data are processed and analyzed using the SEISAN database management software. In addition to the seismic network, we deployed a small-aperture seismic array south of Fumarole Bay. It is composed by 9 vertical and 1 three-component short-period stations. The 24-bit data acquisition system samples these 12 channels at 100 sps. There is also a permanent seismic station operating since 2008 and located near GdC, that is very useful for the preliminary evaluation of the seismicity at the start of the survey. This station is composed by a 16-s electrolytic seismometer (Eentec SP400) and a 24-bit datalogger (Eentec DR4000) sampling at 100 sps. During the 2010-2011 survey we identified 33 regional earthquakes, 80 volcano-tectonic (VT) earthquakes, and 929 long-period (LP) events. The volcanic alert system has remained green (the lowest level) at all times. The seismic activity has been similar to previous surveys and remained within limits that are normal for the island.

Martín, R.; Carmona, E.; Almendros, J.; Serrano, I.; Villaseñor, A.; Galeano, J.

2012-04-01

412

Four Decades of Ozonesonde Measurements Over Antarctica  

NASA Astrophysics Data System (ADS)

Ozonesonde observations from Syowa and the South Pole over more than forty years are described and intercompared. Observations from the two sites reveal remarkable agreement, supporting and extending the understanding gained from either individually. Both sites exhibit extensive Antarctic ozone losses in a relatively narrow altitude range from about 14 to 24 km in October, and the data are consistent with temperature-dependent chemistry involving chlorine on polar stratospheric clouds as the cause of the ozone hole. The maximum October ozone losses at higher altitudes near 18 km (70 hPa) appear to be transported to lower levels near the tropopause on a time scale of a few months, which is likely to affect the timing of the effects of ozone depletion on possible tropospheric climate changes. Both sites also show greater ozone losses in the lowermost stratosphere after the volcanic eruption of Mt. Pinatubo, supporting the view that surface chemistry can be enhanced by volcanic perturbations and that the very deep ozone holes observed in the early 1990s reflected such enhancements. Sparse data from the Syowa station in the early 1980s also suggest that enhanced ozone losses due to the El Chichon eruption may have contributed to the beginning of a measurable ozone hole. Observations at both locations show that some ozone depletion now occurs during much if not all year at lower altitudes near 12-14 km. Correlations between temperature and ozone provide new insights into ozone losses, including its non-linear character, maximum effectiveness, and utility as a tool to distinguish dynamical effects from chemical processes. These data also show that recent changes in ozone do not yet indicate ozone recovery linked to changing chlorine abundances, but provide new tools to probe observations for the first such future signals.

Hofmann, D. J.; Solomon, S.; Oltmans, S. J.; Portman, R. W.; Sasaki, T.; Thompson, D. W.

2005-12-01

413

Four decades of ozonesonde measurements over Antarctica  

NASA Astrophysics Data System (ADS)

Ozonesonde observations from Syowa and the South Pole over more than 40 years are described and intercompared. Observations from the two sites reveal remarkable agreement, supporting and extending the understanding gained from either individually. Both sites exhibit extensive Antarctic ozone losses in a relatively narrow altitude range from about 12 to 24 km in October, and the data are consistent with temperature-dependent chemistry involving chlorine on polar stratospheric clouds as the cause of the ozone hole. The maximum October ozone losses at higher altitudes near 18 km (70 hPa) appear to be transported to lower levels near the tropopause on a timescale of a few months, which is likely to affect the timing of the effects of ozone depletion on possible tropospheric climate changes. Both sites also show greater ozone losses in the lowermost stratosphere after the volcanic eruption of Mt. Pinatubo, supporting the view that surface chemistry can be enhanced by volcanic perturbations and that the very deep ozone holes observed in the early 1990s reflected such enhancements. Sparse data from the Syowa station in the early 1980s also suggest that enhanced ozone losses due to the El Chichon eruption may have contributed to the beginning of a measurable ozone hole. Observations at both locations show that some ozone depletion now occurs during much if not all year at lower altitudes near 12-14 km. Correlations between temperature and ozone provide new insights into ozone losses, including its nonlinear character, maximum effectiveness, and utility as a tool to distinguish dynamical effects from chemical processes. These data also show that recent changes in ozone do not yet indicate ozone recovery linked to changing chlorine abundances but provide new tools to probe observations for the first such future signals.

Solomon, Susan; Portmann, Robert W.; Sasaki, Toru; Hofmann, David J.; Thompson, David W. J.

2005-11-01

414

Airborne Surveys Conducted by SOAR for Geologic Studies in Antarctica, 1998-2001  

NASA Astrophysics Data System (ADS)

During the three austral summers that occurred in the period October, 1998 to February, 2001, the Support Office for Aerogeophysical Research (SOAR) of the University of Texas Institute for Geophysics (UTIG) conducted aerogeophysical campaigns for eight separate projects in both East and West Antarctica. Measurements were made of magnetic and gravitational fields, surface elevation and sub-glacial bed elevation. Surveys were accomplished with a modified deHavilland Twin Otter aircraft equipped with a towed magnetometer, gyro-stabilized gravity meter, laser altimeter, ice-penetrating radar, and carrier-phase GPS receivers. Diurnal variations of the geomagnetic field were measured at nearby base stations where static GPS data were collected for differential aircraft positioning. Four of the experiments performed were designed to address fundamental geologic questions when combined with ground-based studies and/or geophysical modeling in studies by multiple investigators at several institutions. In western Marie Byrd Land (MBL), a 330 x 440 km survey (line spacing ranged from 5.3 x 5.3 km to 10.6 x 10.6 km) was flown in order to understand the tectonic and geologic devolpment of the boundary between the Ross Sea Rift and the MBL volcanic province. A series of corridors were flown across the Transantarctic Mountains (TAM) in order to study extreme and variable rift flank uplift. These consist of a 100 x 810 km corridor extending from Ice Stream B across the Watson Escarpment and into central East Antarctica beyond South Pole, a 100 x 1170 km corridor from Ross Island to Dome C, and a single line across the TAM near Robb Glacier (line spacing for corridors was 10 km with 30 km tie-lines). Three parallel lines, 1300 km long and separated by 5 km, were flown from near Taylor Dome to AGO4, complementing a passive seismic array planned in order to investigate the crust and upper mantle structure beneath the East-West Antarctic boundary. Another survey was performed in order to help determine the geologic setting and structure of the Lake Vostok environment to guide future studies. The survey block was 157.5 x 330 km (line spacing 7.5 km with 11.25 km and 22.5 km tie-lines), augmented by 12 regional lines extending 180 to 440 km outward from the primary grid. In-field data processing and subsequent analyses have shown that data quality is high for nearly all portions of these surveys.

Holt, J. W.

2001-05-01

415

Towards a deeper understanding of 17O-excess in Antarctica  

NASA Astrophysics Data System (ADS)

For many decades stable water isotopes (?D and ?18O) are used as tracers in Earth's hydrological cycle in order to get information about climatic parameters. In the low latitudes, water isotopes trace precipitation rate (amount effect), history of air masses, regional convection or water vapor transport. In higher latitudes, ?D and ?18O are directly linked to condensation temperature at first order while the combination of both in d-excess [= ?D - 8 ?18O] gives indication on source climatic conditions. The development of 17O-excess [= ln(?17O + 1) - 0.528ln(?18O + 1)], resulting from the combination of ?17O and ?18O, now provides an additional isotopic tracer which has been shown to be primary influenced by relative humidity at evaporation. Here, we show the results of 17O-excess of five different ice cores sites covering the remote centre and coastal regions of East Antarctica. We performed 17O-excess measurements on ice cores of Vostok (VK), EPICA Dome C (EDC), TALDICE (TD), Law Dome (LD) and EPICA Dronning Maud Land (EDML) for the period of the last deglaciation. The coastal sites of TD and LD show a constant 17O-excess over the last deglaciation and seem to faithfully record the variations in relative humidity at the evaporative regions providing moisture to Antarctica. This finding strongly contrasts with the 17O-excess increase (up to 20 ppm) at the remote sites of VK and EDC, where alternative mechanisms, going beyond the dependence on relative humidity at evaporation, may be at play: first, isotopic model studies suggest that 17O-excess may strongly depend on water vapor supersaturation, especially for sites with low ?18O (< -50 permil) values. Second, we address the question if stratospheric water vapor deposition may influence the isotopic signature of 17O-excess in the very arid sites of VK and EDC. We therefore present inter annual cycle of 17O-excess over a snow pit at the Vostok station and compare these results with possible proxies for stratospheric air intrusions.

Winkler, R.; Landais, A.; Prié, F.; Oerter, H.; Petit, J.; Stenni, B.; Moy, A. D.; van Ommen, T. D.; Fourre, E.; Jean-Baptiste, P.; Masson-Delmotte, V.; Jouzel, J.

2011-12-01

416

Antarctica: The Continuing Experiment. Foreign Policy Association Headline Series, No. 273.  

ERIC Educational Resources Information Center

|One of a series of booklets on world issues examines the sharpened differences between those nations that have declared sovereignty over parts of Antarctica and those that have not; between those nations that have arbitrarily assumed responsibility for the administration of Antarctica and the smaller, more numerous nations that believe their…

Quigg, Philip W.

417

Seasonal shifts in the provisioning behavior of chinstrap penguins, Pygoscelis antarctica  

Microsoft Academic Search

Whether parents are able to adapt food gathering to rising offspring demands, or if they are controlled largely by extrinsic factors, is important for understanding key limits on fitness. Over seven breeding seasons, we studied the provisioning behavior of chinstrap penguins, Pygoscelis antarctica, at Seal Island, Antarctica, during parents' transition to leave broods of one or two chicks unguarded. By

John K. Jansen; Robert W. Russell; William R. Meyer

2002-01-01

418

Rare earth elements in the water column of Lake Vanda, McMurdo Dry Valleys, Antarctica  

Microsoft Academic Search

We present data on the composition of water from Lake Vanda, Antarctica. Vanda and other lakes in the McMurdo Dry Valleys of Antarctica are characterized by closed basins, permanent ice covers, and deep saline waters. The meromictic lakes provide model systems for the study of trace metal cycling owing to their pristine nature and the relative simplicity of their biogeochemical

Eric Heinen de Carlo; William J. Green

2002-01-01

419

Anatomical Features and Ultrastructure of Deschampsia antarctica (Poaceae) Leaves from Different Growing Habitats  

Microsoft Academic Search

? Background and Aims The leaf anatomy and ultrastructure of Deschampsia antarctica (Poaceae) plants growing in three different habitats (a dry site in the Antarctic tundra, a wet site in a zone exposed to sea spray and a greenhouse) were investigated. The ultrastructure of the leaves of D. antarctica has not been studied before. ? Methods Semi-thin sections of the

E WA S ZCZUKA; J OZEF B EDNARA; R Y S Z A R D G ORECKI

2005-01-01

420

Colony Size of Phaeocystis Antarctica (Prymnesiophyceae) as Influenced by Zooplankton Grazers  

EPA Science Inventory

The haptophyte Phaeocystis antarctica is a dominant phytoplankton species in the Ross Sea, Antarctica, and exists as solitary cells and mucilaginous colonies that differ by several orders of magnitude in size. Recent studies with P. globosa suggested that colony formation and enl...

421

Survival and Recovery of Phaeocystis Antarctica (Prymnesiophyceae) from Prolonged Darkness and Freezing  

EPA Science Inventory

The colony-forming haptophyte Phaeocystis antarctica is an important primary producer in the Ross Sea, and must survive long periods of darkness and freezing in this extreme environment. We conducted experiments on the responses of P. antarctica-dominated phytoplankton assemblage...

422

Additions to the Eocene selachian fauna of Antarctica with comments on Antarctic selachian diversity  

Microsoft Academic Search

Antarctic Eocene selachians were reported from the La Meseta Formation of Seymour Island and from glacial erratics of Mount Discovery, Antarctica. Seymour Island has produced the most diverse Palaeogene selachian fauna of the Southern Hemisphere so far. Up to now, 23 selachian taxa (20 sharks, 2 rays) have been described from the Eocene of Antarctica. Recent geological and palaeontological investigations

Jürgen Kriwet

2005-01-01

423

Validation of ocean tide models around Antarctica using onshore GPS and gravity data  

Microsoft Academic Search

Ocean tide models around Antarctica are presently only sparsely tested against independent data. Ocean tide modeling errors, along with subsequent ocean tide loading (OTL) displacement modeling errors, alias into altimetry and time variable gravity (e.g., Gravity Recovery and Climate Experiment (GRACE)) time series, for example. To validate various ocean tide models around Antarctica, GPS data from 15 sites have been

Matt A. King; Nigel T. Penna; Peter J. Clarke; Ed C. King

2005-01-01

424

A network of autonomous surface ozone monitors in Antarctica: technical description and first results  

Microsoft Academic Search

A suite of 10 autonomous ozone monitors, each powered using renewable energy, was developed and built to study surface ozone in Antarctica during the International Polar Year (2007-2009). The monitoring systems were deployed in a network around the Weddell Sea sector of coastal Antarctica with a transect up onto the Antarctic Plateau. The aim was to measure for a full

S. J.-B. Bauguitte; N. Brough; M. M. Frey; A. E. Jones; D. J. Maxfield; H. K. Roscoe; M. C. Rose; E. W. Wolff

2010-01-01

425

A network of autonomous surface ozone monitors in Antarctica: technical description and first results  

Microsoft Academic Search

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 monitoring systems were deployed in a network around the Weddell Sea sector of coastal Antarctica with a transect up onto the Antarctic Plateau. The aim was to measure for a

S. J.-B. Bauguitte; N. Brough; M. M. Frey; A. E. Jones; D. J. Maxfield; H. K. Roscoe; M. C. Rose; E. W. Wolff

2011-01-01

426

Continent-wide risk assessment for the establishment of nonindigenous species in Antarctica  

Microsoft Academic Search

Invasive alien species are among the primary causes of biodiversity change globally, with the risks thereof broadly understood for most regions of the world. They are similarly thought to be among the most significant conservation threats to Antarctica, especially as climate change proceeds in the region. However, no comprehensive, continent-wide evaluation of the risks to Antarctica posed by such species

S. L. Chown; A. H. L. Huiskes; N. J. M. Gremmen; J. E. Lee; A. Terauds; K. Crosbie; Y. Frenot; K. A. Hughes; S. Imura; K. Kiefer; M. Lebouvier; B. Raymond; M. Tsujimoto; C. Ware; B. van de Vijver; D. M. Bergstrom

2012-01-01

427

The Stable Isotopes of Atmospheric Methane: Long-Term Observations at Alert (Canada) and Neumayer (Antarctica)  

NASA Astrophysics Data System (ADS)

Ten years records of CH4 concentration, 13C/12C-CH4 and 2H/H-CH4 from the background stations Alert, Arctic, (82.45° N) and Neumayer, Antarctica, (70.65° S) are presented. High volume integrated (Alert) and spot (Neumayer) samples are collected at the respective sites and are analysed in Heidelberg using GC-FID technique for mixing ratios, IRMS for 13C/12C and 2H/H ratios, and, in the last two years, a TDLAS system for analysis of the 2H/H ratio. At Neumayer we observe a seasonal CH4 cycle with a peak-to-peak amplitude of about 28 ppb; minimum mixing ratios are ocurring in February/March, and maxima in August/September. The seasonalities of 13C/12C and 2H/H are anticorrelated to the mixing ratio and average 0.12 ‰ (13C/12C) and 2.4 ‰ (2H/H) peak-to-peak. Seasonal cycles at Neumayer can be explained by the seasonality of methane destruction in combination with a seasonally varying meridional circulation pattern in the atmosphere. The atmospheric OH sink (which contributes about 90% to the total sink of atmospheric methane) is stronger during summer. The long-term trends at Neumayer are 5.8 ppb/yr (mixing ratio), 0.04 ‰ /yr (13C/12C) and 0.8 ‰ /yr (2H/H). At Alert we observe a seasonal amplitude of CH4 about twice as large as at Neumayer, while the 13C/12C and 2H/H seasonality is larger by a factor of three, with minimum mixing ratios in July, and maxima in January/February (isotopes almost anticorrelated, whereas minimum isotope ratios occur 2-3 month earlier than the maximum mixing ratios). Compared to Antarctica which is far away from any source region additional influences from methane sources lead to the larger seasonalities at Alert: The nearby wetland sources are emitting CH4 during the summer season but they do not seem to affect much the mixing ratio. This is different for the isotope ratios. High methane concentrations during the winter months are caused by transport of stratified polluted air masses from mid latitudes to the Arctic station during this season. The long-term trends at Alert are 3.6 ppb/yr (mixing ratio), 0.03 ‰ /yr (13C/12C) and 1.4 ‰ /yr (2H/H). At Alert and at Neumayer the mixing ratios are almost constant (except for seasonality) since about three years. From the difference between both stations a fractionation of -7.2 ‰ (13C/12C) and -234 ‰ (2H/H) for the mean tropospheric methane sink can be derived. The same results are obtained from the analysis of the southern hemispheric seasonal cycle. With the two approaches one can estimate the isotopic signature of the mean source to -53.9 ‰ (13C/12C) and -275 ‰ (2H/H). The continuing long term trend in both stable isotopes shows that in contrast to the mixing ratio the isotopes are still not in steady state with its sources and sinks.

Poss, C.; Veidt, C.; Worthy, D. E.; Levin, I.

2003-12-01

428

Hydrogen Filling Station  

SciTech Connect

Hydrogen is an environmentally attractive transportation fuel that has the potential to displace fossil fuels. The Freedom CAR and Freedom FUEL initiatives emphasize the importance of hydrogen as a future transportation fuel. Presently, Las Vegas has one hydrogen fueling station powered by natural gas. However, the use of traditional sources of energy to produce hydrogen does not maximize the benefit. The hydrogen fueling station developed under this grant used electrolysis units and solar energy to produce hydrogen fuel. Water and electricity are furnished to the unit and the output is hydrogen and oxygen. Three vehicles were converted to utilize the hydrogen produced at the station. The vehicles were all equipped with different types of technologies. The vehicles were used in the day-to-day operation of the Las Vegas Valley Water District and monitoring was performed on efficiency, reliability and maintenance requirements. The research and demonstration utilized for the reconfiguration of these vehicles could lead to new technologies in vehicle development that could make hydrogen-fueled vehicles more cost effective, economical, efficient and more widely used. In order to advance the development of a hydrogen future in Southern Nevada, project partners recognized a need to bring various entities involved in hydrogen development and deployment together as a means of sharing knowledge and eliminating duplication of efforts. A road-mapping session was held in Las Vegas in June 2006. The Nevada State Energy Office, representatives from DOE, DOE contractors and LANL, NETL, NREL were present. Leadership from the National hydrogen Association Board of Directors also attended. As a result of this session, a roadmap for hydrogen development was created. This roadmap has the ability to become a tool for use by other road-mapping efforts in the hydrogen community. It could also become a standard template for other states or even countries to approach planning for a hydrogen future. Project partners also conducted a workshop on hydrogen safety and permitting. This provided an opportunity for the various permitting agencies and end users to gather to share experiences and knowledge. As a result of this workshop, the permitting process for the hydrogen filling station on the Las Vegas Valley Water District’s land was done more efficiently and those who would be responsible for the operation were better educated on the safety and reliability of hydrogen production and storage. The lessons learned in permitting the filling station and conducting this workshop provided a basis for future hydrogen projects in the region. Continuing efforts to increase the working pressure of electrolysis and efficiency have been pursued. Research was also performed on improving the cost, efficiency and durability of Proton Exchange Membrane (PEM) hydrogen technology. Research elements focused upon PEM membranes, electrodes/catalysts, membrane-electrode assemblies, seals, bipolar plates, utilization of renewable power, reliability issues, scale, and advanced conversion topics. Additionally, direct solar-to-hydrogen conversion research to demonstrate stable and efficient photoelectrochemistry (PEC) hydrogen production systems based on a number of optional concepts was performed. Candidate PEC concepts included technical obstacles such as inefficient photocatalysis, inadequate photocurrent due to non-optimal material band gap energies, rapid electron-hole recombination, reduced hole mobility and diminished operational lifetimes of surface materials exposed to electrolytes. Project Objective 1: Design, build, operate hydrogen filling station Project Objective 2: Perform research and development for utilizing solar technologies on the hydrogen filling station and convert two utility vehicles for use by the station operators Project Objective 3: Increase capacity of hydrogen filling station; add additional vehicle; conduct safety workshop; develop a roadmap for hydrogen development; accelerate the development of photovoltaic components Project Objective 4:

Boehm, Robert F; Sabacky, Bruce; Anderson II, Everett B; Haberman, David; Al-Hassin, Mowafak; He, Xiaoming; Morriseau, Brian

2010-02-24

429

Multi-decadal surface temperature trends near the Ice Divide of East Antarctica using borehole firn temperature measurements and inversion method  

NASA Astrophysics Data System (ADS)

The objective of this investigation is to detect multi-decadal surface temperature trends near the Ice Divide of East Antarctica. The interior of East Antarctic Ice Sheet (EAIS) remains as one of the least explored areas on earth. In recent years there have been several studies attempting to reconstruct the surface temperature history of Antarctica for the past 50 years using several approaches. However the lack of in situ data has hindered the science community in reaching a conclusive answer about Antarctic climate change, and in particular for the EAIS. In order to gain a better assessment of Antarctic climate change, additional data sources are needed to reduce the current uncertainty. Surface temperature inversion from firn temperature measurements will provide a source of climate reconstruction independent of firn chemistry, sparse weather data, satellite data or ice cores. During the Norwegian-U.S. IPY Scientific Traverse of East Antarctica, in austral summer of 2007-08, thermal-profiling units were installed at three locations (76.06 ° S, 22.46 ° E, Traverse site NUS07-2; 78.65 ° S, 35.64 ° E, NUS07-5, 126 km from Plateau Station; 82.07 ° S, 54.9 ° E, NUS07-7, 2 km from the Pole of Inaccessibility). Each unit consists of 16 PRTs (Platinum Resistance Thermometers) distributed between 0.2 and 90 m in depth. Wired PRTs were lowered into the borehole after an ice core was drilled and before the hole was back-filled with granulated snow to prevent air circulation and provide thermal conduction between PRTs and firn. Near-hourly data are being transmitted through ARGOS satellite telemetry system. The overall uncertainty in firn temperature measurement is between 0.02 and 0.03 ° C. Mean temperature gradients between -0.5 and -0.75 ° C were found between 16 and 90 m at three sites, with standard deviations less then 0.03 ° C. These gradients are larger than or about the same as previously published studies that modeled temperature profile under a steady-state climatic condition. Our results suggest a cooling to no significant trend near the Ice Divide of East Antarctica for the past several decades. Detailed analysis with the application of inversion method is ongoing to determine how the observed signals in the temperature profiles translate in to magnitudes and temporal scales of the surface temperature trends. A positive temperature gradient, suggesting recent warming, was identified for the top of the Greenland ice sheet (Summit station) and will be discussed in comparison.

Muto, A.; Scambos, T. A.; Steffen, K.

2008-12-01

430

Space Station Tethered Elevator System.  

National Technical Information Service (NTIS)

The optimized conceptual engineering design of a space station tethered elevator is presented. The elevator is an unmanned mobile structure which operates on a ten kilometer tether spanning the distance between the Space Station and a tethered platform. E...

L. A. Anderson

1989-01-01

431

Survey of Satellite Power Stations.  

National Technical Information Service (NTIS)

The Energy Research and Development Administration established on 15 March 1976 the Task Group on Satellite Power Stations to recommend to the ERDA Administrator the appropriate role, if any, of satellite power station research and development in ERDA's o...

C. E. Bloomquist

1976-01-01

432

Network Multiple Station Discriminant Functions.  

National Technical Information Service (NTIS)

An extension is made of linear discriminant analysis to the case where multiple station observations are available for each event. Multivariate regression is used to estimate the mean vectors and covariance matrix in the multiple station discriminant func...

R. Shumway R. R. Blandford

1972-01-01

433

A DORIS determination of the absolute velocities of the Sorsdal and Mellor glaciers in Antarctica  

NASA Astrophysics Data System (ADS)

The Lambert-Amery System is the largest glacier-ice shelf system in East Antarctica, draining a significant portion of the ice sheet. Variation in ice sheet discharge from Antarctica or Greenland has an impact on the rate of change in global mean sea level; which is a manifestation of climate change. In conjunction with a measure of ice thickness change, ice sheet discharge can be monitored by determining the absolute velocities of these glaciers. In order to demonstrate the capability of the DORIS system to determine glacier velocities, Geoscience Australia undertook a Pilot Project under the auspices of the International DORIS Service. A DORIS beacon was deployed on the Sorsdal (November 2001 - January 2002 and November 2003 - January 2004) and Mellor (December 2002 - January 2003) glaciers. The DORIS data, transmitted from the autonomously operating ground beacon for each satellite pass, were stored in the receiver on-board the satellite and later downlinked to the DORIS control centres for processing. This paper describes the campaigns that were conducted at the Sorsdal and Mellor glaciers, the data processing standards for modelling the Doppler measurements, precise orbit determination of the satellites using the data from the globally distributed DORIS network, tracking station position and reference frame modelling, the point positioning mode employed for determining the position and velocities of the transmitting beacon antennas located on the glaciers and provides the velocity estimates that have been determined from the analysis of these tracking data. For the Sorsdal 2001/2002 campaign, using SPOT-4 data only, the measured effective horizontal ice motion was estimated to be 30 ± 0.4 cm/day (azimuth of N246°E ± 0.1°). The inferred velocities for the Sorsdal 2003/2004 campaign, using SPOT-4 and SPOT-5 data, was 5.7 ± 0.8 cm/day (azimuth of N264°E ± 7.5°) for the first eight days and 11.4 ± 1.4 cm/day (azimuth of N241°E ± 1.5°) for the subsequent 21 days. There was a noted decrease in the inferred velocities between the beginning and the end of the observing period. A sub-division of the latter 21 day observing period into three segments showed a decrease in 2D velocity from 18.3 ± 0.7 to 11.2 ± 0.7 cm/day and then to 7.4 ± 0.9 cm/day for the first, second and third segments, respectively. In comparison, a GPS derived velocity over the time-span of the 2001/2002 Sorsdal campaign gave a mean ice flow rate of 31 cm/day. The GPS velocity was derived from two daily position estimates 65 days apart. The DORIS determination from 26 days of continuous SPOT-4 and SPOT-5 data compared well with the GPS derived velocity. For the 2002/2003 Mellor glacier campaign, using SPOT-4 and SPOT-5 data, the estimated average ice velocity was 104 ± 25 cm/day (azimuth of N33°E ± 0.1°); which compared well with an InSAR derived velocity of between 110 and 137 cm/day. The point positioning technique as implemented in this study was further validated and assessed by replicating the computational process to determine the position and velocity of the permanent International DORIS Service site at Terre Adélie, Antarctica. Through these experiments, it has been successfully demonstrated that the DORIS system is capable of determining the velocities of glaciers with an accuracy of a few cm/day over a period of several weeks; operating in remote regions in an autonomous mode. With an increasing number of DORIS-equipped satellites and multiple daily passes, it has the potential to measure glacial velocities at a high temporal resolution (sub-daily).

Govind, R.; Valette, J. J.; Lemoine, F. G.

2010-06-01

434

Robotic dissolution station  

DOEpatents

This invention is comprised of a robotic station for dissolving active metals in acid in an automated fashion. A vessel with cap, containing the active metal is placed onto a shuttle which retracts to a point at which it is directly beneath a cap removing and retaining mechanism. After the cap is removed, a tube carrying an appropriate acid is inserted into the vessel, and the acid is introduced. The structure of the station forms an open hood which is swept of gases generated by the dissolution and the air removed to a remote location for scrubbing. After the reaction is complete, the shuttle extends and the vessel may be removed by a robot arm.

Beugelsdijk, T.J.; Hollen, R.M.; Temer, D.J.; Haggart, R.J.; Erkkila, T.H.

1991-12-31

435

Bamfield Marine Station  

NSDL National Science Digital Library

The station provides year-round research facilities and technical assistance to scientists from the five western Canadian universities as well as visiting scientists, offers courses for undergraduate and graduate students in the marine sciences, and runs a public education program for schools and interested groups of all ages. Information includes all the latest research news and events, plus field trip and community projects information. Explore OceanLink and Ocean News for an abundance of education resources.

436

Medicina Station Report  

NASA Astrophysics Data System (ADS)

The Medicina 32-m dish is an alt-az antenna run by the Istituto di Radioastronomia di Bologna del Consiglio Nazionale delle Ricerche. The radiotelescope is located about 30 km east of Bologna, Italy. It is part of the European VLBI Network. Details on the telescope characteristics and equipments can be found at the EVN Home Page (http://www.nfra.nl/evn/). In the last couple of years, the main goal at the Medicina Station was to get the telescope agile in changing the observing frequency. Achieving this goal will greatly increase the observational efficiency of the telescope. Moreover it will make the operation of changing the receivers more safe and it makes this task independent of weather conditions. The first part of the project has been completed and the new subreflector is fully in operation. The increased flexibility in changing frequency, together with the facility of recording both thick and thin tapes implemented at all the European VLBI Network (EVN) stations has immediately produced an increase in the number of geodetic VLBI observations to which the Medicina Station will take part in 1999.

Orfei, Allesandro

1999-08-01

437

Microscope Imaging Station  

NSDL National Science Digital Library

The Exploratorium in San Francisco continue to break new and intriguing ground with their latest online project, the Microscope Imaging Station. The actual physical Station resides at their museum, and was opened in 2004. Developed to complement this interactive exhibit, this online manifestation of the Station allows visitors to peer into the cells of living organisms such as sea urchins and zebrafish. The sea urchin feature is a real treat, as it is accompanied by a well-written essay on how this spiky creature may help unlock the secrets of genes, reproduction, and cancer. If that wasn't enough, the essay (as with other features on the site) includes a short video clip. The "Gallery" is definitely worth a stop as well. Here, visitors will find a wide range of high-resolution images and movies created with research-grade microscopes. Watching cells move, the fertilization process and the world of mitosis is a rather nice way to spend a few minutes, and visitors will probably want to pass the site along to friends and family.

438

Magnetic Screening and Multivariate Techniques in Antarctic Soils, Marambio Station  

NASA Astrophysics Data System (ADS)

Antarctic stations are an interesting and particular field for pollution research because of the small area of influence and the reduced number of sources. The present contribution constitutes one of the first studies of magnetic screening and heavy metal pollution on Antarctica (Marambio station, 64° 14'S; 56° 37'W), being a suitable method for contamination assessment in Antarctic areas. Among magnetic studies, magnetic susceptibility, anhysteric and isothermal remanent magnetisation and thermal studies were carried out. Magnetite-like carriers are especially dominant in samples collected near pollution sources. Among several heavy metals, lead and zinc are the main trace elements reaching high values, both are end products derived from fuel combustion and residues, solid waste and paints. The magnetic and heavy metal measurements, and related maps of this case study can be considered as a reference in the area for future work. The correlation results between magnetic and chemical variables show moderate relationships varying from 0.409 to 0.663. Moreover, canonical correlation analysis showed very good canonical correlations: R= 0.950. On the other hand, other multivariate techniques were studied in order to classify the data according to the degree of contamination, principal coordinates and discriminant analyses, as well as the comparison of several multivariate means were performed. Therefore, three groups were distinguished, which were well classified at a low margin of error and quite different from each other at a significant level: 0.01.

Chaparro, M. A.; Lirio, J. M.; Chaparro, M. A.; Nuñez, H.; Marinelli, C.; Gogorza, C. S.; Sinito, A. M.

2007-05-01

439

A prototype station for ARIANNA: A detector for cosmic neutrinos  

NASA Astrophysics Data System (ADS)

The Antarctic Ross Ice Shelf Antenna Neutrino Array (ARIANNA) is a proposed detector for ultra-high energy astrophysical neutrinos. It will detect coherent radio Cherenkov emission from the particle showers produced by neutrinos with energies above about 1017 eV. ARIANNA will be built on the Ross Ice Shelf just off the coast of Antarctica, where it will eventually cover about 900 km2 in surface area. There, the ice-water interface below the shelf reflects radio waves, giving ARIANNA sensitivity to downward-going neutrinos and improving its sensitivity to horizontally incident neutrinos. ARIANNA detector stations each will contain 4-8 antennas, which search for pulses of 50 MHz to 1 GHz radio emission from neutrino interactions.We describe a prototype station for ARIANNA, which was deployed in Moore’s Bay on the Ross Ice Shelf in December 2009, discuss the design and deployment, and present some initial figures on performance. The ice shelf thickness was measured to be 572±6 m at the deployment site.

Gerhardt, Lisa; Klein, Spencer; Stezelberger, Thorsten; Barwick, Steve; Dookayka, Kamlesh; Hanson, Jordan; Nichol, Ryan

2010-12-01

440

Solar power stations in space  

Microsoft Academic Search

Basic features of several design concepts for a solar power station to be located in a geostationary orbit are discussed, including a solar thermal power station (Patha et al., 1974), the satellite solar power station (SSPS) proposed by Glaser (1974), and the modular solar energy satellite, (MOSES) proposed by Ruth (1974). Technological obstacles in the development of a design combining

R. Ockert; G. Wirths

1975-01-01

441

Numerical modeling of coastal polynyas in East Antarctica  

NASA Astrophysics Data System (ADS)

Coastal polynyas are the area of open water or thin ice surrounded by coastline and thick ice in winter, ranging in the horizontal scale from a few to 100 km. In coastal polynyas, large heat loss occurs due to the direct contact of open water/thin ice with the colder air. As a result of the large heat loss, coastal polynyas exhibit high sea-ice production rates. The high sea-ice production leads to formation of dense shelf water. Around Antarctica, such dense shelf water formed in the coastal polynyas plays an important role in the formation and spreading of Antarctic Bottom Water. Using a sea ice - ocean coupled model with fine horizontal resolution around East Antarctica ( ~ 15 km), sea-ice production and dense shelf water formation in the coastal polynyas are investigated. The model well reproduces the locations of coastal polynyas and high sea-ice production there. In East Antarctica, the Cape Darnley polynya (CDP) is the highest sea-ice production area and the Mertz Glacier polynya (MGP) is the second highest one in the model. Water denser than 27.88 kg m-3 over the shelf is formed in coastal polynyas. Besides the CDP and the MGP, polynyas near Barrier Bay, Shackleton Ice Shelf, Vincenness Bay, Dibble Iceberg Tongue, and Ninnis Glacier also contribute to dense shelf water formation. Sea-ice production largely depends on the value of the minimum sea-ice thickness in a grid. To model the formation of frazil ice and high sea-ice production in coastal polynyas, a large value of the minimum sea-ice thickness ( 50 cm in this study) is required. Blocking effect of sea-ice transport by grounded icebergs is also tested by the model. From a series of numerical experiments, we found that the blocking effect has a large impact on both sea-ice production and dense shelf water formation in coastal polynyas.

Kusahara, K.; Hasumi, H.

2008-12-01

442

Accumulation rates across Pine Island and Thwaites Glaciers, West Antarctica  

NASA Astrophysics Data System (ADS)

Amundsen Coast glaciers, particularly Pine Island and Thwaites, are thinning at some of the largest rates observed across Antarctica, increasing concern over their current and future contribution to sea-level rise and impact on ice-sheet stability. Lack of sufficient ground-based measurements of surface mass balance components, especially accumulation rate, impedes our ability to constrain the magnitude of glacier mass imbalance across this region. As a result, continent-wide accumulation rate datasets differ substantially over large areas of West Antarctica. By generating accumulation rates from airborne radar imaging, we improve basin-wide estimates as well as spatial understanding of the accumulation rate variability over Pine Island and Thwaites glacier catchments. During the 2009-10 summer field season, the CReSIS accumulation radar was flown over 70,000 km across West Antarctica. We manually digitize firn layers visible in the radar echograms and tie these isochrons back to existing ice-core sites, thereby dating each firn layer using age-correlated depths at the core site. The spatially varying depths of each digitized layer are then converted to accumulation rates by dividing the cumulative mass estimated from core density profiles by the layer age. Thus far we find the radar capable of mapping layers at depths between ~3 and 175 m, which corresponds to layer ages between 5 and >400 years. The Pine Island catchment on average experiences a higher accumulation rate and more extreme spatial variability than Thwaites. Local maxima in accumulation rate near the coast are up to 10 times greater than rates inland. We are currently incorporating accumulation rates derived from Operation IceBridge snow radar to our existing dataset to further improve spatial coverage over these glaciers.

Medley, B.; Joughin, I. R.; Conway, H.; Das, S. B.; Criscitiello, A. S.; Steig, E. J.; Gogineni, P. S.; Lewis, C.

2011-12-01