Sample records for casey station antarctica

  1. Hydraulic performance of a permeable reactive barrier at Casey Station, Antarctica.

    PubMed

    Mumford, K A; Rayner, J L; Snape, I; Stevens, G W

    2014-12-01

    A permeable bio-reactive barrier (PRB) was installed at Casey Station, Antarctica in 2005/06 to intercept, capture and degrade petroleum hydrocarbons from a decade old fuel spill. A funnel and gate configuration was selected and implemented. The reactive gate was split into five separate cells to enable the testing of five different treatment combinations. Although different treatment materials were used in each cell, each treatment combination contained the following reactive zones: a zone for the controlled release of nutrients to enhance degradation, a zone for hydrocarbon capture and enhanced degradation, and a zone to capture excess nutrients. The materials selected for each of these zones had other requirements, these included; not having any adverse impact on the environment, being permeable enough to capture the entire catchment flow, and having sufficient residence time to fully capture migrating hydrocarbons. Over a five year period the performance of the PRB was extensively monitored and evaluated for nutrient concentration, fuel retention and permeability. At the end of the five year test period the material located within the reactive gate was excavated, total petroleum hydrocarbon concentrations present on the material determined and particle size analysis conducted. This work found that although maintaining media reactivity is obviously important, the most critical aspect of PRB performance is preserving the permeability of the barrier itself, in this case by maintaining appropriate particle size distribution. This is particularly important when PRBs are installed in regions that are subject to freeze thaw processes that may result in particle disintegration over time. PMID:25078614

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

    PubMed

    Townsend, A T; Snape, I

    2008-01-25

    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

  3. Ozone profiles above Palmer Station, Antarctica

    NASA Technical Reports Server (NTRS)

    Torres, Arnold L.; Brothers, George

    1988-01-01

    NASA's Goddard Space Flight Center/Wallops Flight Facility conducted a series of 52 balloon-borne measurements of vertical ozone profiles over the National Science Foundation (NSF) research facility at Palmer Station, Antarctica (64 deg 46 S, 64 deg 3 W) between August 9 and October 24, 1987. High resolution measurements were made from ground level to an average of 10 mb. While much variation was seen in the profile amounts of ozone, it is clear that a progressive depletion of ozone occurred during the measurement period, with maximum depletion taking place in the 17 to 19 km altitude region. Ozone partial pressures dropped by about 95 percent in this region. Shown here are plotted time dependences of ozone amounts observed at 17 km and at arbitrarily selected altitudes below (13 km) and above (24 km) the region of maximum depletion. Ozone partial pressure at 17 km is about 150nb in early August, and has decreased to less than 10nb in the minimums in October. The loss rate is of the order of 1.5 percent/day. In summary, a progressive depletion in stratospheric ozone over Palmer Station was observed from August to October, 1987. Maximum depletion occurred in the 17 to 19 km range, and amounted to 95 percent. Total ozone overburden decreased by up to 50 percent during the same period.

  4. Measurement of moss growth in continental Antarctica

    Microsoft Academic Search

    P. M. Selkirk; M. L. Skotnicki

    2007-01-01

    Using steel pins inserted into growing moss colonies near Casey Station, Wilkes Land, continental Antarctica, we have measured\\u000a the growth rate of three moss species: Bryum pseudotriquetrum and Schistidium antarctici over 20 years and Ceratodon purpureus over 10 years. This has provided the first long-term growth measurements for plants in Antarctica, confirming that moss shoots\\u000a grow extremely slowly in Antarctica, elongating between

  5. Asteroseismology at the Concordia station in Antarctica

    NASA Astrophysics Data System (ADS)

    Mosser, B.; Siamois Team

    2007-07-01

    SIAMOIS is a project devoted to ground-based asteroseismology, involving an instrument to be installed at the Dome C Concordia station in Antarctica. SIAMOIS provides an asteroseismic programme that can follow the way currently opened by the space project CoRoT, with unique information on G and K type bright stars on the main sequence. In addition, spectrometric observations with SIAMOIS will be able to detect oscillation modes that cannot be analyzed in photometry: the Doppler data, less affected by the stellar activity noise, yield a more precise mode structure inversion. The SIAMOIS concept is based on Fourier Transform interferometry. Such a principle leads to a small instrument designed and developed for the harsh conditions in Antarctic. The instrument will be fully automatic, with no moving parts, and a very simple initial set up in Antarctic. The dedicated scientific programme will avoid the complications related to a versatile instrument. Data reduction will be performed in real time, and the transfer of the asteroseismic data to Europe will require only a modest bandwidth. SIAMOIS will observe with a dedicated small 40-cm telescope. Dome C appears to be the ideal place for ground-based asteroseismic observations. The unequalled weather conditions yield a duty cycle as high as 90% over 3 months, as was observed during the 2005 wintering. This high duty cycle, a crucial point for asteroseismology, is comparable to the best space-based observations. Long time series (up to 3 months) will be possible, thanks to the long duration of the polar night. SIAMOIS can be seen as one of the very first observational projects in astronomy at Dome C. Its scientific programme will take full advantage of the unique quality of this site, and will constitute a necessary first step in preparation of future more ambitious programmes requiring more sophisticated instrumentation and larger collectors

  6. Status of DORIS stations in Antarctica for precise geodesy

    NASA Technical Reports Server (NTRS)

    Willis, P.; Amalvict, M.; Shibuya, K.

    2005-01-01

    In Antarctica, besides the quite numerous GPS stations, four DORIS stations are permanently operating. In addition to the permanent DORIS stations, episodic campaigns took place at DomeC/Conccordia and on Sorsdal and Lambert glaciers. In this paper, we first collect general information concerning the stations and the campaigns (location, start of measurements, etc). We then present the results of observations of the permanent stations keeping in mind that we are primarily interested here in the vertical component, which is the most uncertain component.

  7. Observations of Pc2 waves by Cluster and ground stations in Antarctica

    NASA Astrophysics Data System (ADS)

    Liu, Y.

    2013-12-01

    We analyzed a Pc2 wave event above the He+ cyclotron frequency detected by the four Cluster satellites and multiple ground stations in Antarctica. During the wave event, Cluster satellites were located sunward from L~13 in the outer magnetosphere to the magnetopause, over 13o - 20o magnetic latitude, north of the equator near local magnetic noon. The Poynting flux results show that the wave packet energy propagated dominantly along the geomagnetic field direction and in alternating directions rather than uni-directionally from the equator, implying the wave source was located in a high latitude region away from the equator, where a minimum in the B field is located. The footprint of Cluster was closest to the Zhong Shan and Davis (ZHS/DAV) stations (L~14) in Antarctica. Consequently, the frequency range and the burst-pattern of the dynamic spectra from ZHS and DAV are highly consistent with those seen by Cluster. Although wave packets on Cluster occurred from 0800 UT to 1430 UT, lasting for 6.5 hours, the wave bursts on ZHS and DAV stations were concentrated earlier at 0800-1040 UT. This suggests the azimuthal extent of the wave source may be estimated at 2.6 hours and the wave packets were guided by the field lines from Cluster to ZHS/DAV. The waves at Mawson (L~9) and Casey (L~38.8) are rather weak and the wave burst-patterns appear obviously different from those at ZHS/DAV and Cluster, suggesting the wave energy propagated toward both high and low latitudes via the inonospheric waveguide.

  8. Variations of tropospheric ozone concentration of Syowa Station, Antarctica

    Microsoft Academic Search

    Shohei Murayama; Takakiyo Nakazawa; Masayuki Tanaka; Shuhji Aoki; Sadao Kawaguchi

    1992-01-01

    The paper reports aircraft measurements of the tropospheric O3 concentration made over Syowa Station, Antarctica, from May 1989 to January 1990. The O3 concentration increased with height for the entire period. Lower tropospheric O3 exhibited a prominent seasonal variation with maximum concentration in winter and minimum concentration in summer. In the upper troposphere, the concentration reached high values in winter,

  9. Atmospheric CO2 record from continuous measurements at Jubany Station, Antarctica

    E-print Network

    Atmospheric CO2 record from continuous measurements at Jubany Station, Antarctica Graphics Location The Italian PNRA (National Research Program in Antarctica) began continuous atmospheric carbon Jubany Station, Antarctica 62°14' S, 58°40' W 15 m right MSL #12;Period of Record March 1994 - December

  10. JARE Syowa Station 11-m Antenna, Antarctica

    NASA Technical Reports Server (NTRS)

    Aoyama, Yuichi; Doi, Koichiro; Shibuya, Kazuo

    2013-01-01

    In 2012, the 52nd and the 53rd Japanese Antarctic Research Expeditions (hereinafter, referred to as JARE-52 and JARE-53, respectively) participated in five OHIG sessions - OHIG76, 78, 79, 80, and 81. These data were recorded on hard disks through the K5 terminal. Only the hard disks for the OHIG76 session have been brought back from Syowa Station to Japan, in April 2012, by the icebreaker, Shirase, while those of the other four sessions are scheduled to arrive in April 2013. The data obtained from the OHIG73, 74, 75, and 76 sessions by JARE-52 and JARE-53 have been transferred to the Bonn Correlator via the servers of National Institute of Information and Communications Technology (NICT). At Syowa Station, JARE-53 and JARE-54 will participate in six OHIG sessions in 2013.

  11. The 50-MHz meteor radar observation at Syowa Station, Antarctica

    NASA Technical Reports Server (NTRS)

    Tanaka, T.; Ogawa, T.; Igarashi, K.; Fujii, R.

    1985-01-01

    The 50-MHz Doppler radar installed at Syowa Station (69 deg 00'S, 39 deg 35'E), Antarctica, in 1982 can detect continuously a meteor echo if an operator assigns the meteor mode operation to the radar. The radar has two narrow antenna beams (4 deg in the horizontal plane), one toward geomagnetic south and the other toward approximately geographic south, with a crossing angle of about 33 deg. The minicomputer annexed to the radar controls the transmission and reception of a 50-MHz wave. If the receiver detects a meteor echo, the flag signal is sent to the computer. Then the computer begins to determine the echo range with a time resolution of 1 micro s and to sample every 200 microns/s for 1 s the Doppler signal and echo intensity at the particular range (R). The line-of-sight velocity (V sub D) of the echo trail is calculated from the output from the Doppler signal detection circuit having an offset frequency by using the so-called zero-crossing method. The echo amplitude decay time calculated by a least-mean square method is used to obtain the ambipolar diffusion coefficient (D) and then to calculate the echo height (H). About 120 day observations were made during 1982-1983. Some early results are presented. magnetic tapes together with V sub D, D, H and R for later analysis in Japan. About 120 day observation were made during 1982-1983. Some early results are presented.

  12. Wilkes Land (Casey Station)

    Microsoft Academic Search

    R. D. Seppelt

    \\u000a The Windmill Islands, at around 66 °17 ' S, 110 °32 'E on the eastern side of Vincennes Bay, are a series of peninsulas and\\u000a islands occupying an area of exposed or permanently ice and snow-covered ground of around 105 km2, including an area of approximately 25 km2 of permanently ice-covered terrain between the L øken Moraine line, as an

  13. Radar BackscatterMeasurementsFrom RADARSAT S A R Imagery of South Pole Station, Antarctica

    E-print Network

    Howat, Ian M.

    Radar BackscatterMeasurementsFrom RADARSAT S A R Imagery of South Pole Station, Antarctica Hong backscatter around South Pole Station was measured from several different azimuthal angles using RADARSAT-1 topography* INTRODUCTION Radarsat-1 acquisitions in support of the 1997 Radarsat Antarctic Mapping Project

  14. Lidar observations of the mesospheric sodium layer at Syowa Station, Antarctica

    Microsoft Academic Search

    A. Nomura; T. Kano; Y. Iwasaka; H. Fukunishi; T. Hirasawa; S. Kawaguchi

    1987-01-01

    The results of lidar observations of the mesospheric sodium layer made at Syowa Station, Antarctica from April to October 1985 are reported. There is no significant seasonal variation in the abundance or vertical profile of the sodium density. The nocturnal variations show wavelike structures with a period of 3 to 8 hours and a wavelength of 10 to 16 km

  15. LAMELLARIID GASTROPODS COLLECTED BY JAPANESE ANTARCTIC RESEARCH EXPEDITIONS FROM NEAR SYOWA STATION AND BREID BAY. ANTARCTICA

    Microsoft Academic Search

    Hideki NUMANAMI; Takashi OKUTANI

    Among the benthos materials collected from near Syowa Station, Breid Bay and Gunnerus Bank, Antarctica, four species of the lamellariid gastro- pods were found. The descriptions on a new species Marseniopsis syowaensis n. sp., and two known species, M. conica and M. mollis are given. A single specimen considered to be a new species from Breid Bay is described. Some

  16. Ozone profiles at McMurdo Station, Antarctica, the austral spring of 1990

    Microsoft Academic Search

    T. Deshler; D. J. Hofmann

    1991-01-01

    Vertical profiles of ozone and temperature were measured on 40 occasions during the austral spring of 1990 at McMurdo Station, Antarctica, and once again near record levels of ozone depletion were observed. Total ozone decreased from 260 DU in late August to its minimum value of 145 DU on October 9, when the ozonesonde was at its lower detection limit

  17. Visible spectroscopy at McMurdo Station, Antarctica

    SciTech Connect

    Solomon, S.

    1987-09-01

    Ground-based observations and satellite data confirm that total ozone abundance over Antarctica during the austral spring has decreased by 50 percent during the last 10 years. As participants in the 1986-1987 National Ozone Expedition, the author measured as many stratospheric chemical constituents as possible to obtain a better understanding of chemical and dynamic processes that may contribute to this decline. Data from last austral spring indicate that abundances of ozone-destroying chlorine compounds were about 29 to 50 times greater than anticipated and vary diurnally. Although these data, as well as lower than expected abundances of nitrogen dioxide, are consistent with the theory that enhanced chlorine chemistry is causing the ozone depletion, these findings do not prove that this model is correct. To augment his data base, during austral spring 1987, the author will continue to use ground-based visible absorption spectroscopy to measure the stratospheric column abundances of ozone, nitrogen compounds, and chlorine compounds. This method provides simultaneous measurements of ozone change and the abundances of reactive nitrogen and reactive chlorine species. Possible correlations between simultaneous measurements of these three constituents are valuable for distinguishing between proposed mechanisms of ozone depletion. The author will take measurements using direct light from the Sun and Moon or by measuring the scattered light from the zenith sky.

  18. Feasibility of wind turbine diesel hybrid generators at McMurdo station, Antarctica. Final report

    SciTech Connect

    Scott, L.B. Jr.; Wrigglesworth, W.; Blair, J.L.; Watters, R.

    1983-03-01

    The purpose of this report is to present the results of a study to determine the feasibility of a wind-turbine/diesel hybrid system for the generation of electricity at McMurdo Station, Antarctica. This introduction gives a short description of past and present energy systems at McMurdo, and describes some projected energy systems within which wind turbine generators would function. Feasibility is then discussed in terms of certain variables and performance parameters characterizing diesel-electric and wind turbine generator systems, and constraints defining the successful operation of these systems at McMurdo Station.

  19. Application of ground-penetrating radar at McMurdo Station, Antarctica

    SciTech Connect

    Stefano, J.E.

    1992-01-01

    Argonne National Laboratory initiated a site investigation program at McMurdo Station, Antarctica, to characterize environmental contamination. The performance and usefulness of ground-penetrating radar (GPR) was evaluated under antarctic conditions during the initial site investigation in January 1991. Preliminary surveys were successful in defining the contact between reworked pyroclastic material and in the prefill, undisturbed pyroclastics and basalts at some sites. Interference from radio traffic at McMurdo Station was not observed, but interference was a problem in work with unshielded antennas near buildings. In general, the results of this field test suggest that high-quality, high-resolution, continuous subsurface profiles can be produced with GPR over most of McMurdo Station.

  20. Application of ground-penetrating radar at McMurdo Station, Antarctica

    SciTech Connect

    Stefano, J.E.

    1992-05-01

    Argonne National Laboratory initiated a site investigation program at McMurdo Station, Antarctica, to characterize environmental contamination. The performance and usefulness of ground-penetrating radar (GPR) was evaluated under antarctic conditions during the initial site investigation in January 1991. Preliminary surveys were successful in defining the contact between reworked pyroclastic material and in the prefill, undisturbed pyroclastics and basalts at some sites. Interference from radio traffic at McMurdo Station was not observed, but interference was a problem in work with unshielded antennas near buildings. In general, the results of this field test suggest that high-quality, high-resolution, continuous subsurface profiles can be produced with GPR over most of McMurdo Station.

  1. Immune System Dysregulation and Latent Herpesvirus Reactivation During Winterover at Concordia Station, Dome C, Antarctica

    NASA Technical Reports Server (NTRS)

    Crucian, B. E.; Feuerecker, M.; Salam, A. P.; Rybka, A.; Stowe, R. P.; Morrels, M.; Meta, S. K.; Quiriarte, H.; Quintens, Roel; Thieme, U.; Kaufmann, I.; Baatout, D. S.; Pierson, D. L.; Sams, C. F.; Chouker, A.

    2011-01-01

    Immune system dysregulation occurs during spaceflight and consists of altered peripheral leukocyte distribution, reductions in immunocyte function and altered cytokine production profiles. Causes may include stress, confinement, isolation, and disrupted circadian rhythms. All of these factors may be replicated to some degree in terrestrial environments. NASA is currently evaluating the potential for a ground-based analog for immune dysregulation, which would have utility for mechanistic investigations and countermeasures evaluation. For ground-based space physiology research, the choice of terrestrial analog must carefully match the system of interest. Antarctica winter-over, consisting of prolonged durations in an extreme/dangerous environment, station-based habitation, isolation and disrupted circadian rhythms, is potentially a good ground-analog for spaceflight-associated immune dysregulation. Of all Antarctica bases, the French-Italian Concordia Station, may be the most appropriate to replicate spaceflight/exploration conditions. Concordia is an interior base located in harsh environmental conditions, and has been constructed to house small, international crews in a station-environment similar to what should be experienced by deep space astronauts. The ESA-NASA CHOICE study assessed innate and adaptive immunity, viral reactivation and stress factors during Concordia winterover deployment. The study was conducted over two winterover missions in 2009 and 2010. Final study data from NASA participation in these missions will be presented.

  2. Work plan for the preliminary site investigation for McMurdo Station, Ross Island, Antarctica

    SciTech Connect

    Stefano, J.E.; Patton, T.L.; McGinnis, L.D.; Bebrich, C.A.; Knudson, D.A.; Picel, K.C.

    1991-05-01

    This document presents the final work plan for the preliminary site investigation to be conducted at McMurdo Station, Ross Island, Antarctica. A draft version of this report was presented to the National Science Foundation (NSF) in January 1991. This work plan includes a brief site description and background, a discussion of the environmental setting, a sampling and analytical program for data collection, and a brief description of sampling and data management procedures. A description of the geologic and geophysical investigation to be conducted is also included. 18 refs., 4 figs., 4 tabs.

  3. Special Session: the future of astronomy at the dome C concordia station in antarctica

    NASA Astrophysics Data System (ADS)

    Fossat, E.

    2002-06-01

    The franco-italian station Concordia will be operational in 2004, and 15 persons could spend winter there. The qualification of the astronomical site and the first observations in infrared imagery and visible photometry are scheduled for the first winters. The potential of this site appears so promising that we must not ignore antarctica in the european large projects propective debate. I will review what is already known, and what we are going to measure to be certain, and speak about collaborations that are being established.

  4. Geochemical markers of soil anthropogenic contaminants in polar scientific stations nearby (Antarctica, King George Island).

    PubMed

    Prus, Wojciech; Fabia?ska, Monika J; ?abno, Rados?aw

    2015-06-15

    The organic contamination of Antarctic soils and terrestrial sediments from nearby of five polar scientific stations on King George Island (Antarctica) was investigated. Gas chromatography-mass spectrometry (GC-MS) was applied to find composition of dichloromethane extracts of soil and terrestrial sediments. The presence of geochemical markers, such as n-alkanes, steranes, pentacyclic triterpenoids, and alkyl PAHs, their distribution types, and values of their ratios indicates the predominating source of organic fossil fuels and products of their refining rather than from the natural Antarctic environment. Fossil fuel-originated compounds well survived in conditions of Antarctic climate over long times thus enabling to characterize geochemical features of source fossil fuel identified as petroleum expelled from kerogen II of algal/bacterial origins deposited in sub-oxic conditions and being in the middle of catagenesis. Both microbial activity and water leaching play an important role in degradation of terrestrial oil spills in the Antarctica climate, and petroleum alteration occurs lowly over long periods of time. Synthetic anthropogenic compounds found in terrestrial Antarctica sediments included diisopropylnaphthalenes, products of their sulfonates degradation in paper combustion, and organophosporus compounds used as retardants and plasticizers. PMID:25770449

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

    Microsoft Academic Search

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

    2008-01-01

    Isotopic compositions of sulfur (delta34S) and oxygen (delta18O) 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

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

    NASA Astrophysics Data System (ADS)

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

    2009-12-01

    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.

  7. Casey Porto Executive Director

    E-print Network

    Duchowski, Andrew T.

    at the National Renewable Energy Laboratory (NREL), managed for the U.S. Department of Energy by the Alliance market adoption of existing energy efficiency and renewable energy solutions. Prior to NREL, Casey

  8. Japanese-German joint airborne geophysical surveys around Syowa Station, Antarctica

    NASA Astrophysics Data System (ADS)

    Nogi, Y.; Steinhage, D.; Riedel, S. R.; Kitada, K.; Shiraishi, K.; Shibuya, K.; Jokat, W.

    2006-12-01

    The evolution of Antarctica and the Antarctic Ocean is vital to understanding the growth and breakup of super continent Gondwana. The area around Syowa Station, the Japanese Antarctic wintering Station in Lützow- Holm Bay, is considered to be a junction of Africa, India, Madagascar, and Antarctic continents from the reconstruction model of Gondwana. Therefore this area is a key to investigate the formation and fragmentation of Gondwana. However, the tectonic evolution is still speculative because geological evidence is limited to a few isolated outcrops and the coverage with geophysical surveys in this area is poor. To reveal the tectonic evolution related to Gondwana formation and breakup in this area, joint Japanese-German airborne geophysical surveys around Syowa Station had been conducted in January 2006 during the 47th Japanese Antarctic Research Expedition. Ice radar, magnetic, and gravity data are obtained onshore and offshore areas using the AWI owned Polar2, a fixed wing Dornier aircraft (Do228-101) on skis. We present preliminary results of magnetic, gravity, and ice thickness (bed rock topography) measurements around Syowa Station obtained by the airborne geophysical survey 2006 and discuss the tectonic evolution in this area.

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

    NASA Astrophysics Data System (ADS)

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

    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.

  10. Ozone profiles at McMurdo Station, Antarctica, the austral spring of 1990

    SciTech Connect

    Deshler, T. (Univ. of Wyoming, Laramie (United States)); Hofmann, D.J. (NOAA Climate Monitoring and Diagnostics Lab., Boulder, CO (United States))

    1991-04-01

    Vertical profiles of ozone and temperature were measured on 40 occasions during the austral spring of 1990 at McMurdo Station, Antarctica, and once again near record levels of ozone depletion were observed. Total ozone decreased from 260 DU in late August to its minimum value of 145 DU on 9 October, when the ozonesonde was at it's lower detection limit from 15 to 16.5 km. Ozone reductions were observed almost exclusively between 12 and 20 km, with a half life of 20 days. This is similar to previous years. Although McMurdo was within the polar vortex for most of the period, there were several occasions when the edge of the vortex was over McMurdo. During these periods, ozone above 20 km approximately doubled, but below 20 km remained relatively unchanged.

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

    SciTech Connect

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

    1990-02-01

    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.

  12. FY 1994 ambient air monitoring report for McMurdo Station, Antarctica

    SciTech Connect

    Lugar, R.M.

    1994-12-01

    This report presents the results of ambient air monitoring performed during the 1994 fiscal year (FY 1994) in the vicinity of McMurdo Station, Antarctica. Routine monitoring was performed during the 1993-1994 austral summer at three locations for airborne particulate matter less than 10 micrometers (PM-10) and at two locations for carbon monoxide (CO), sulfur dioxide (SO{sub 2}), and nitrogen oxides (NO, NO{sub 2}, and NO{sub x}). Selected PM-10 filters were analyzed for arsenic, beryllium, cadmium, chromium, lead, mercury, and nickel. Additional air samples were collected at three McMurdo area locations and at Black Island for determination of the airborne concentration of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). Sampling site selection, sampling procedures, and quality assurance procedures used were consistent with US Environmental Protection Agency guidance for local ambient air quality networks.

  13. Mapping sediment contamination and toxicity in Winter Quarters Bay, McMurdo Station, Antarctica.

    PubMed

    Crockett, Alan B; White, Gregory J

    2003-07-01

    Winter Quarters Bay (WQB) is a small embayment located adjacent to McMurdo Station, the largest research base in Antarctica. The bay is approximately 250 m wide and long, with a maximum depth of 33 m. Historically, trash from the McMurdo Station was piled on the steep shoreline of WQB, doused with fuel and ignited. That practice has ceased, and the adjacent land area has been regraded to cover the residual waste. The bottom of WQB remains littered with drums, equipment, tanks, tires, cables, and other objects, especially the southeastern side of the bay where dumping took place. Sediments are contaminated with PCBs, metals, and hydrocarbon fuels. The objectives of this study were to map the distribution of organic contaminants in WQB, assess the toxicity of WQB sediments using a simple microbial test, and determine correlations between toxicity and contaminant levels. The study suggests that adverse ecological effects have occurred from one or more of the contaminants found in WQB but the source of the toxic impacts to bay sediments remains unknown. Whole sediment toxicity was only correlated with oil-equivalent while solvent extracts of sediments were correlated with PAHs and oil-equivalent. The authors recommend that an integrated research plan be developed that focuses on determining what additional information is needed to make informed decisions on possible remediation of WQB. PMID:12841689

  14. Draft Genome Sequence of Arthrobacter gangotriensis Strain Lz1yT, Isolated from a Penguin Rookery Soil Sample Collected in Antarctica, near the Indian Station Dakshin Gangotri

    PubMed Central

    Ara, Sreenivas; Bandi, Sunil; Singh, Aditya; Kumar Pinnaka, Anil

    2013-01-01

    We report here the 4.3-Mb genome of Arthrobacter gangotriensis strain Lz1yT, isolated from a penguin rookery soil sample collected in Antarctica, near the Indian station Dakshin Gangotri. PMID:23766407

  15. Draft Genome Sequence of Arthrobacter gangotriensis Strain Lz1yT, Isolated from a Penguin Rookery Soil Sample Collected in Antarctica, near the Indian Station Dakshin Gangotri.

    PubMed

    Shivaji, Sisinthy; Ara, Sreenivas; Bandi, Sunil; Singh, Aditya; Kumar Pinnaka, Anil

    2013-01-01

    We report here the 4.3-Mb genome of Arthrobacter gangotriensis strain Lz1y(T), isolated from a penguin rookery soil sample collected in Antarctica, near the Indian station Dakshin Gangotri. PMID:23766407

  16. Kory Hanley Casey Peters

    E-print Network

    Valtorta, Marco

    Arduino Kory Hanley Casey Peters Brandon Cox #12;Overview Arduino is an open-source single development environment #12;The History Arduino means "Brave Friend" in Italian Created in 2005 in Ivrea, Italy Arduino team: Massimo Banzi, David Cuartielles, Tom Igoe, Gianluca Martino and David Mellis #12

  17. Distribution of Clostridium perfringens and Fecal Sterols in a Benthic Coastal Marine Environment Influenced by the Sewage Outfall from McMurdo Station, Antarctica

    Microsoft Academic Search

    DIANE D. EDWARDS; GORDON A. MCFETERS; M. INDIRA VENKATESAN

    1998-01-01

    The spatial distribution, movement, and impact of the untreated wastewater outfall from McMurdo Station, Antarctica, were investigated under early austral summer conditions. The benthic environment was examined to determine the distribution of Clostridium perfringens in sediment cores and the intestinal contents of native invertebrates and fish along a transect of stations. These stations extended ca. 411 m south of the

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

    SciTech Connect

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

    1997-01-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-04-01

    Unusual aerosol enhancement is often observed at Syowa Station, Antarctica, during winter and 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 micropulse lidar (MPL) in August and September 2012. During 13-15 August, aerosol enhancement occurred immediately after a storm condition. A high backscatter ratio and high aerosol concentrations were observed from the surface to ca. 2.5 km over Syowa Station. Clouds appeared occasionally at the top of the aerosol-enhanced layer during the episode. Aerosol enhancement was terminated on 15 August by strong winds from 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 (Universal Time) on 5 September despite 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 to 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 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). Continuous MPL measurements indicate that high aerosol enhancement occurred mostly in surface-lower free troposphere (3 km) during the period July-September.

  20. Distribution of ? 18 O in surface snow along a transect from Zhongshan Station to Dome A, East Antarctica

    Microsoft Academic Search

    MingHu Ding; CunDe Xiao; Bo Jin; JiaWen Ren; DaHe Qin; WeiZhen Sun

    2010-01-01

    Surface snow samples were collected during the 14th (1997\\/1998) and 24th (2007\\/2008) Chinese National Antarctica Research\\u000a Expeditions along a transect from Zhongshan Station to Dome A. The stable oxygen isotope ratios of these samples were measured\\u000a to investigate their relationships with temperature and geographical parameters (latitude, longitude, altitude and distance\\u000a to the coast). The results reveal a strong positive correlation

  1. Ice velocity from static GPS observations along the transect from Zhongshan station to Dome A, East Antarctica

    Microsoft Academic Search

    Zhang Shengkai; E. Dongchen; Wang Zemin; Li Yuansheng; Jin Bo; Zhou Chunxia

    2008-01-01

    Dome A, the highest point on the Antarctic ice sheet at just over 4000 m a.s.l., is located near the centre of East Antarctica. Chinese National Antarctic Research Expeditions have studied icesheet dynamics and mass balance along a traverse route from Zhongshan station to Dome A during the austral summers from 1996\\/97 to 2004\\/05. Nineteen GPS sites were occupied on

  2. Ozone profiles at McMurdo Station, Antarctica during he spring of 1993; record low ozone season

    Microsoft Academic Search

    B. J. Johnson; T. Deshler; R. Zhao

    1995-01-01

    Record low ozone was measured by balloon-borne ozonesondes (40 flights) at McMurdo Station, Antarctica (78 deg S) during the 1993 austral spring. Total column ozone declined by 55% from an initial 275 Dobson Units (DU) on 30 August to a minimum of 130 +\\/- 7 DU on 2 October. Ozone within the 12-20 km showed a 95% decrease from an

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

    Microsoft Academic Search

    M. A. Carroll; S. Solomon; A. L. Schmeltekopf; R. W. Sanders

    1989-01-01

    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 à 10¹³

  4. Polar stratospheric clouds and volcanic aerosol during spring 1992 over McMurdo Station, Antarctica: Lidar and particle counter comparisons

    Microsoft Academic Search

    A. Adriani; T. Deshler; G. Di Donfrancesco; G. P. Gobbi

    1995-01-01

    Coordinated observations with lidar and balloon-borne particle counters were used to characterize polar stratospheric clouds and to estimate a particle index of refraction. The index of refraction was estimated from comparisons of calculated and measured scattering ratios at a wavelength of 532 nm. The clouds, measured from McMurdo Station, Antarctica (78°S), were observed above 11 km at temperatures below 198

  5. AIRS Observations of DomeC in Antarctica and Comparison with Automated Weather Stations (AWS)

    NASA Technical Reports Server (NTRS)

    Aumann, Hartmut H.; Gregorich, Dave; Broberg, Steve

    2006-01-01

    We compare the surface temperatures at Dome Concordia (DomeC) deduced from AIRS data and two Automatic Weather Stations at Concordia Station: AWS8989 , which has been in operation since December 1996, and AWS.it, for which data are available between January and November 2005. The AWS8989 readings are on average 3 K warmer than the AWS.it readings, with a warmer bias in the Antarctic summer than in the winter season. Although AIRS measures the skin brightness temperature, while the AWS reports the temperature of the air at 3 meter above the surface, the AIRS measurements agree well with the AWS.it readings for all data and separately for the summer and winter seasons, if data taken in the presence of strong surface inversions are filtered out. This can be done by deducing the vertical temperature gradient above the surface directly from the AIRS temperature sounding channels or indirectly by noting that extreme vertical gradients near the surface are unlikely if the wind speed is more than a few meters per second. Since the AIRS measurements are very well calibrated, the agreement with AWS.it is very encouraging. The warmer readings of AWS8989 are likely due to thermal contamination of the AWS8989 site by the increasing activity at Concordia Station. Data from an AWS.it quality station could be used for the evaluation of radiometric accuracy and stability of polar orbiting sounders at low temperatures. Unfortunately, data from AWS.it was available only for a limited time. The thermal contamination of the AWS8989 data makes long-term trends deduced from AWS8989 and possibly results about the rapid Antarctic warming deduced from other research stations on Antarctica suspect. AIRS is the first hyperspectral infrared sounder designed in support of weather forecasting and climate research. It was launched in May 2002 on the EOS Aqua spacecraft into a 704 km altitude polar sun-synchronous orbit. The lifetime of AIRS, estimated before launch to be at least 5 years is, based on the latest evaluation, limited by the amount of attitude control gas on the EOS Aqua spacecraft, which is expected to last through 2015.

  6. Sources of PM10 and sulfate aerosol at McMurdo Station, Antarctica.

    PubMed

    Mazzera, D M; Lowenthal, D H; Chow, J C; Watson, J G

    2001-10-01

    Source contributions to PM10 and sulfate aerosol at McMurdo Station, Antarctica during the austral summers of 1995-1996 and 1996-1997 were estimated using Chemical Mass Balance (CMB) receptor modeling. The average PM10 (particles with aerodynamic diameters less than 10 microm) concentration at Hut Point, located less than 1 km downwind of downtown McMurdo, was 3.4 microg/m3. Emissions profiles were determined for potentially important aerosol source types in McMurdo: exposed soil, power generation, space heating, and surface vehicles. Soil dust, sea salt, combustion emissions, sulfates, marine biogenic emissions as methanesulfonate, and nitrates contributed 57%, 15%, 14%, 10%, 3%, and 1%, respectively, of average estimated PM10 at Hut Point (3.2 microg/m3). Soil dust, sea salt, and combustion sources contributed 12%, 8%, and 20%, respectively, of the average PM10 sulfate concentration of 0.46 microg/m3. Marine biogenic sources contributed 0.17 microg/m3 (37%). The remaining sulfate is thought to have come from emissions from Mt. Erebus or hemispheric pollution sources. PMID:11592425

  7. Stratospheric ClO profiles from McMurdo Station, Antarctica, spring 1992

    NASA Technical Reports Server (NTRS)

    Emmons, L. K.; Shindell, D. T.; Reeves, J. M.; De Zafra, R. L.

    1995-01-01

    We describe ground-based measurements of ClO made at McMurdo Station, Antarctica, during September and October 1992. Vertical profiles were retrieved from molecular rotational emission spectra at 278 GHz. Peak mixing ratios of 1.6 +/- 0.3 ppbv were seen in mid-September at approximately 18 km altitude, suggestive of somewhat larger quantities than were measured at the same site and season in 1987. As the core of the polar vortex moved away from McMurdo by early October, the ClO mixing ratio at this altitude dropped to less than 0.2 ppbv, coincident with increasing temperature, ozone, and NO2. The diurnal variation of ClO was also observed. The lower stratospheric layer from 15 to 27 km was found to reach approximately midday abundance by 2 - 3 hours after sunrise. The column abundance in this layer began to decrease by the period 4 - 2 hours before sunset and had declined to approximately one quarter of its midday value by 2 - 0 hours before sunset. In contrast, the ClO column in the upper stratosphere, from 28 to 50 km, built up slowly until midday and remained large while sunlight persisted.

  8. Ozone profiles over McMurdo Station, Antarctica, during August, September, and October of 1986 - 1991

    NASA Technical Reports Server (NTRS)

    Deshler, Terry; Hofmann, David J.

    1994-01-01

    Vertical profiles of ozone and temperature have been measured at McMurdo Station, Antarctica, during the springs of 1986 to 1991, roughly every two days from 25 August to 31 October. Comparisons of temporal histories and average vertical structure for these years reveals some striking consistency in the ozone depletion process. Ozone depletion generally begins in early September, and with a half-life of 20-30 days, reaches its maximum in mid-October. The depletion occurs almost exclusively between 12 and 20 km. At the time of maximum depletion total ozone has been decreased roughly 40 percent while ozone between 12 and 20 km has been reduced 80 percent. Recovery generally begins in late October with the influx, above 20 km, of ozone rich air from the lower latitudes. From this record the worst years for ozone depletion were 1987, 1989, and 1990. A new region of ozone depletion, below 12 km, was observed in 1991, coinciding with the entrainment of a volcanic cloud into the polar vortex.

  9. Results of TSP metals monitoring at McMurdo Station, Antarctica

    SciTech Connect

    Lugar, R.M.

    1994-04-01

    This report presents the results of ambient air monitoring of metals in total suspended particulate (TSP) matter performed during the 1992--1993 austral summer at McMurdo Station, Antarctica. Seven samples of TSP were collected from three different locations and analyzed for arsenic, beryllium, cadmium, chromium, lead, nickel, and mercury. Critical-flow high-volume air samplers with a sample flow rate of approximately 1.1 m{sup 3}/minute were used to collect the particulate matter on quartz fiber filters for subsequent laboratory analysis. Sampling site selection, sampling procedures, and quality assurance procedures used were consistent with US Environmental Protection Agency guidance for local ambient air quality networks. The data indicate that McMurdo operations have a measurable impact on the qualitative toxic metals composition of suspended particulate matter in the ambient air; however a definitive quantitative impact could not be concluded. The levels measured are well below the US National Ambient Air Quality Standards and American Conference of Governmental Industrial Hygienists worker exposure levels. Lead was the most prevalent of the seven toxic metals and was detected in all samples at concentrations ranging from 1.4 ng/m{sup 3} to 38 ng/m{sup 3}. Data on the concentration of eleven other metal species are presented. Most notable was the relatively high abundance of titanium and copper, which were detectable at levels up to 2,100 ng/m{sup 3} and 230 ng/m{sup 3}, respectively.

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

    NASA Astrophysics Data System (ADS)

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

    2013-01-01

    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 a.m.s.l.). The data set covers the period from February 2008 to January 2010, however, due to very low CO concentrations below approximately 80 km altitude in summer, profiles can only be retrieved during 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 Aura/MLS and 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 in the same order of magnitude. The ground based radiometer shows high and significant correlation (coefficients higher than 0.9/0.65 compared to MLS/SD-WACCM) at all altitudes compared with both reference datasets. doi:10.5285/DE3E2092-406D-47A9-9205-3971A8DFB4A9

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

    NASA Astrophysics Data System (ADS)

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

    2013-06-01

    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.

  12. Results of PM{sub 10} and TSP monitoring at McMurdo Station, Antarctica

    SciTech Connect

    Lugar, R.M.

    1993-05-01

    This report presents the results of ambient air monitoring of particulate matter performed during the 1992-1993 austral summer in the vicinity of McMurdo Station, Antarctica. Thirty three 24-hour samples were collected from three locations for determination of the concentration of particulate matter less that 10 micrometers (PM{sub 10}), and seven samples collected for determination of total suspended particulate matter (TSP) concentration. Critical flow high volume air samplers with a sample flow rate of approximately 1.1 m{sup 3}/min. were used to collect the particulate matter on quartz fiber filters for subsequent gravimetric analysis. Sampling site selection, sampling procedures, and quality assurance procedures used were consistent with US Environmental Protection Agency guidance for local ambient air quality networks. Mean austral summer PM{sub 10} levels in the McMurdo locale were 3 {mu}g/m{sup 3} at the predominantly upwind location, 9 {mu}g/m{sup 3} at a location approximately 500 meters downwind of the station, and 16 {mu}g/m{sup 3} at a {open_quotes}downtown{close_quotes} location. All PM{sub 10} results were below the US National Ambient Air Quality Standard. TSP results at all locations were greater than PM{sub 10} concentrations; ranging from 8 {mu}g/m{sup 3} at the upwind location to a maximum measurement of 276 {mu}g/m{sup 3} at the {open_quotes}downtown{close_quotes} location. The initial baseline effort demonstrated that site selection and sampling equipment performance were satisfactory, and provided useful data for assessing the impact of McMurdo operations on the local ambient air quality.

  13. Direct evidence of histopathological impacts of wastewater discharge on resident Antarctic fish (Trematomus bernacchii) at Davis Station, East Antarctica.

    PubMed

    Corbett, Patricia A; King, Catherine K; Stark, Jonathan S; Mondon, Julie A

    2014-10-15

    During the 2009/2010 summer, a comprehensive environmental impact assessment (EIA) of the wastewater discharge at Davis Station, East Antarctica was completed. As part of this, histological alteration of gill and liver tissue in Antarctic Rock-cod (Trematomus bernacchii) from four sites along a spatial gradient from the wastewater outfall were assessed. All fish within 800 m of the outfall exhibited significant histological changes in both tissues. Common pathologies observed in fish closest to the outfall include proliferation of epithelial cells with associated secondary lamellar fusion in the gills and multifocal granulomata with inflammation and necrosis as well as cysts in the liver. Fish from sites >800 m from the outfall also exhibited alterations but to a lesser degree, with prevalence and severity decreasing with increasing distance from the outfall. This study highlights the value of histopathological investigations as part of EIAs and provides the first evidence of sub-lethal alteration associated with wastewater discharge in East Antarctica. PMID:25173596

  14. Investigation of crystal anisotropy using seismic data from Kohnen Station, Antarctica

    NASA Astrophysics Data System (ADS)

    Diez, Anja; Eisen, Olaf; Weikusat, Ilka; Lambrecht, Astrid; Mayer, Christoph; Hofstede, Coen; Bohlen, Thomas; Miller, Heinrich

    2014-05-01

    The flow behavior of glaciers and ice sheets is influenced by a preferred orientation of the anisotropic ice crystals. Knowledge about crystal anisotropy is mainly provided by crystal orientation fabric (COF) data from ice cores. To gain a broader understanding about the distribution of crystal anisotropy in ice sheets and glaciers we use seismic measurements. Two effects are important: (i) sudden changes in crystal orientation fabric (COF) lead to englacial reflections and (ii) the anisotropic fabric induces an angle dependency on the seismic velocities and, thus, also recorded traveltimes. For comparisons of ice core data and seismic results we connect COF data with the elasticity tensor and, thus, determine seismic velocities and reflection coefficients for cone and girdle fabrics from ice-core data. In the Antarctic field season 2012 we carried out a vertical seismic profiling (VSP) survey within the borehole of the EDML ice core and a seismic wideangle survey close to Kohnen Station, Antarctica. From the VSP survey we derive interval velocities and compare these velocities to the theoretically calculated velocities from COF ice-core data. The overall velocity trend derived from the ice-core data is well reflected in the VSP velocities. It shows, that the choice of the monocrystal elasticity tensor for the calculation of velocities from ice-core data is important for a good fit with the VSP velocities. For comparison of seismic data with radar and ice-core data we use stacked traces of the wideangle survey. Thus, we are able to identify COF induced reflections in both the seismic and radar data sets.

  15. Observations of mesospheric nitric oxide and ozone variability above Halley station, Antarctica

    NASA Astrophysics Data System (ADS)

    Newnham, D.; Clilverd, M. A.; Horne, R. B.; Rodger, C. J.; Seppälä, A.; Verronen, P. T.; Andersson, M. E.; Marsh, D. R.; Kovacs, T.; Plane, J. M. C.

    2014-12-01

    Production of odd nitrogen species (NOx = NO + NO2) in the polar middle atmosphere by energetic electrons and protons, and its effect in chemically perturbing stratospheric ozone distributions, is well established. NOx is likely to be produced frequently and persistently in the mesosphere and lower thermosphere by energetic electrons. However the electron processes are less well understood than those involving solar protons. Uncertainties include which electron energy ranges have the greatest impact on NOx concentrations either by direct production or indirectly via transport. We have investigated the effect of energetic electron precipitation on nitric oxide (NO) and ozone abundances in the Antarctic middle atmosphere close to solar maximum. During 2013 low to moderate geomagnetic activity occurred, with minimum Dst index of - 132 nT, driven primarily by sub-storms associated with coronal mass ejections. Near-continuous ground-based observations were made by a semi-autonomous 230-250 GHz passive microwave radiometer at Halley station (75°37'S, 26°14'W, L = 4.6, geomagnetic latitude -62°), Antarctica. This location is directly under the region of radiation belt electron precipitation, equator-ward of the auroral zone, and deep within the polar vortex during the Austral winter. We observe enhanced mesospheric NO volume mixing ratio reaching 1.6 ppmv at 65-80 km on 2013 day 158 (7 June). Co-located 30 MHz riometer absorption increased when Kp index ? 4, indicating increased ionisation due to geomagnetic activity at 75-90 km directly above Halley. NOx production by energetic electron precipitation is discussed in the context of Polar-orbiting Operational Environmental Satellites electron count rates for the second generation Space Environment Monitor - Medium Energy Proton and Electron Detector. In order to evaluate the in situ production of NOx versus transport, we have incorporated in the Whole Atmosphere Community Climate Model (WACCM) a reduced version of the Sodankylä Ion-Neutral Chemistry Model. The reduction procedure using the normalised Jacobian method, and initial WACCM results, will be briefly presented.

  16. Electric Vehicle Performance at McMurdo Station (Antarctica) and Comparison with McMurdo Station Conventional Vehicles

    SciTech Connect

    Sears, T.; Lammert, M.; Colby, K.; Walter, R.

    2014-09-01

    This report examines the performance of two electric vehicles (EVs) at McMurdo, Antarctica (McMurdo). The study examined the performance of two e-ride Industries EVs initially delivered to McMurdo on February 16, 2011, and compared their performance and fuel use with that of conventional vehicles that have a duty cycle similar to that of the EVs used at McMurdo.

  17. Anthropogenic disturbance and biodiversity of marine benthic communities in Antarctica: a regional comparison.

    PubMed

    Stark, Jonathan S; Kim, Stacy L; Oliver, John S

    2014-01-01

    The impacts of two Antarctic stations in different regions, on marine sediment macrofaunal communities were compared: McMurdo, a very large station in the Ross Sea; and Casey, a more typical small station in East Antarctica. Community structure and diversity were compared along a gradient of anthropogenic disturbance from heavily contaminated to uncontaminated locations. We examined some of the inherent problems in comparing data from unrelated studies, such as different sampling methods, spatial and temporal scales of sampling and taxonomic uncertainty. These issues generated specific biases which were taken into account when interpreting patterns. Control sites in the two regions had very different communities but both were dominated by crustaceans. Community responses to anthropogenic disturbance (sediment contamination by metals, oils and sewage) were also different. At McMurdo the proportion of crustaceans decreased in disturbed areas and polychaetes became dominant, whereas at Casey, crustaceans increased in response to disturbance, largely through an increase in amphipods. Despite differing overall community responses there were some common elements. Ostracods, cumaceans and echinoderms were sensitive to disturbance in both regions. Capitellid, dorvelleid and orbiniid polychaetes were indicative of disturbed sites. Amphipods, isopods and tanaids had different responses at each station. Biodiversity and taxonomic distinctness were significantly lower at disturbed locations in both regions. The size of the impact, however, was not related to the level of contamination, with a larger reduction in biodiversity at Casey, the smaller, less polluted station. The impacts of small stations, with low to moderate levels of contamination, can thus be as great as those of large or heavily contaminated stations. Regional broad scale environmental influences may be important in determining the composition of communities and thus their response to disturbance, but there are some generalizations regarding responses which will aid future management of stations. PMID:24919053

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

    Microsoft Academic Search

    Knut Stamnes; James Slusser; Melissa Bowen; Charles Booth; Timothy Lucas

    1990-01-01

    Measured UV irradiation data is used in conjunction with a radiative transfer model to determine the seasonal variation in effective biological UV dose, total ozone abundance, and cloud optical depth at McMurdo Station, Antarctica from September 15, 1988 through April 15, 1989. It is noted that comparison of UV radiation levels in Austral spring 1988 and Austral fall 1989 reveals

  19. Several-fold enhancement of biologically effective ultraviolet radiation levels at McMurdo Station, Antarctica during the 1990 ozone 'hole'

    Microsoft Academic Search

    Knut Stamnes; Zhonghai Jin; James Slusser; Charles Booth; Timothy Lucas

    1992-01-01

    Spectral measurements of biologically relevant radiation at McMurdo Station, Antarctica reveal ultraviolet (UV) irradiance levels at 305 nm in October exceeding by a factor between 3 and 6 'normal' values expected for undepleted ozone levels. This enhancement is directly related to the ozone depletion. The column abundance of stratospheric ozone derived from these measurements was as low as 145 Dobson

  20. Ozone over McMurdo Station, Antarctica, austral spring 1986 - Altitude profiles for the middle and upper stratosphere

    NASA Technical Reports Server (NTRS)

    Connor, Brian J.; Barrett, J. W.; Parrish, A.; Solomon, P. M.; De Zafra, R. L.

    1987-01-01

    In the austral spring of 1986, a program of measurements of the ozone altitude profile (for the z values between 25 and 55 km), relevant to an understanding of the ozone hole, was conducted at McMurdo Station, Antarctica. The measurements were performed using ground-based millimeter-wave spectrometry. It was found that the ozone mixing ratio peaked at altitudes ranging from 28 to 34 km, with peak values between 5 and 9 ppm by volume. During the period between September 12 and October 29, the ozone mixing ratio decreased, with great variability, by about 15 percent at 25 km, with no significant decrease at higher altitudes. The observation of the depletion occurring only below 25 km is consistent with ozone-sonde observations during previous years.

  1. Measurement of atmospheric opacity at 278 GHz at McMurdo Station, Antarctica in austral spring seasons, 1986 and 1987

    NASA Technical Reports Server (NTRS)

    De Zafra, R. L.; Jaramillo, M.; Barrett, J.; Emmons, L. K.; Parrish, A.

    1990-01-01

    A quasi-continuous record is presented of atmospheric opacity measured at 278 GHz (1.1 mm wavelength) from the McMurdo Station (Antarctica) during austral spring seasons of 1986 (August 30 - October 30) and 1987 (September 4 - October 13) with measurements taken every 20 minutes (except during storms or other periods of high opacity). All data are reduced to represent opacity in the zenith direction. It was found that, during much of September, the two successive years differed considerably in tropospheric opacity. In 1986, water vapor and attendant opacity were generally lower, due to low tropospheric temperatures. Measured opacities were found to be higher than would be expected from the empirical relationships representing opacity as a function of water vapor column density at mm-wavelengths, as proposed by Rice and Ade (1979), Zammit and Ade (1981), and Liebe (1985).

  2. Quality assurance project plan for the preliminary site investigation for McMurdo Station, Ross Island, Antarctica

    SciTech Connect

    Prasad, S.S.

    1991-05-01

    The quality assurance project plan (QAPjP) is designed to ensure that sampling and analysis activities are scoped and performed to obtain quality data during the preliminary site investigation for McMurdo Station, Ross Island, Antarctica. The QAPjP is prepared in accordance with the guidelines set forth and adopted by the US Environmental Protection Agency (EPA) (1980a, 1986a, 1989a), Argonne National Laboratory (ANL) (1988), and Pentecost and Doctor (1990). This document presents the final QAPjP for the preliminary site investigation. A drat version of this report was presented to the National Science Foundation (NSF) in January 1991. A description of the project and data quality objectives is provided in Section 3.1 of the work plan. Specific health and safety precautions and procedures are presented in the health and safety plan. 17 refs., 2 figs., 11 tabs.

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

    SciTech Connect

    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

    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%.

  4. The controlled ecological life support system Antarctic analog project: Analysis of wastewater from the South Pole Station, Antarctica, volume 1

    NASA Technical Reports Server (NTRS)

    Flynn, Michael T.; Bubenheim, David L.; Straight, Christian L.; Belisle, Warren

    1994-01-01

    The Controlled Ecological Life Support system (CELSS) Antarctic Analog Project (CAAP) is a joint National Science Foundation (NSF) and NASA project for the development, deployment and operation of CELSS technologies at the Amundsen-Scott South Pole Station. NASA goals are operational testing of CELSS technologies and the conduct of scientific studies to facilitate technology selection and system design. The NSF goals are that the food production, water purification, and waste treatment capabilities which will be provided by CAAP will improve the quality of life for the South Pole inhabitants, reduce logistics dependence, and minimize environmental impacts associated with human presence on the polar plateau. This report presents an analysis of wastewater samples taken from the Amundsen-Scott South Pole Station, Antarctica. The purpose of the work is to develop a quantitative understanding of the characteristics of domestic sewage streams at the South Pole Station. This information will contribute to the design of a proposed plant growth/waste treatment system which is part of the CELSS Antarctic Analog Project (CAAP).

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

    NASA Astrophysics Data System (ADS)

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

    2013-09-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

    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 20 ozone profiles per day. The ozone profiles cover the pressure range from 3 hPa 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.

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

    NASA Astrophysics Data System (ADS)

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

    2008-12-01

    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.

  8. Sounding rockets in Antarctica

    NASA Technical Reports Server (NTRS)

    Alford, G. C.; Cooper, G. W.; Peterson, N. E.

    1982-01-01

    Sounding rockets are versatile tools for scientists studying the atmospheric region which is located above balloon altitudes but below orbital satellite altitudes. Three NASA Nike-Tomahawk sounding rockets were launched from Siple Station in Antarctica in an upper atmosphere physics experiment in the austral summer of 1980-81. The 110 kg payloads were carried to 200 km apogee altitudes in a coordinated project with Arcas rocket payloads and instrumented balloons. This Siple Station Expedition demonstrated the feasibility of launching large, near 1,000 kg, rocket systems from research stations in Antarctica. The remoteness of research stations in Antarctica and the severe environment are major considerations in planning rocket launching expeditions.

  9. Casey Doyle: Artist at Play

    ERIC Educational Resources Information Center

    Sanders, James H., III; Doyle, Casey

    2008-01-01

    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.)

  10. Occurrence and metabolic activity of organisms under the ross ice shelf, antarctica, at station j9.

    PubMed

    Azam, F; Beers, J R; Campbell, L; Carlucci, A F; Holm-Hansen, O; Reid, F M; Karl, D M

    1979-02-01

    Seawater samples below the Ross Ice Shelf were collected through an access hole at J9, approximately 400 kilometers from the Ross Sea, Antarctica. The 237-meter water column had sparse populations of bacteria (8.7 x 10(6) to 1.2 x 10(7) per liter), microplankters (10(2) to 10(3) per cubic meter), and zooplankters (10 to 20 per cubic meter) at the depths studied. Microbial biomass estimates from cellular adenosine 5'-triphosphate measurements were very low (10 to 150 nanograms of carbon per liter), comparable with values for the abyssal ocean. Microbial populations assimilated tritiated D-glucose, thymidine, uridine, and adenosine triphosphate at extremely low rates, comparable with deep-sea heterotrophic populations. Sediment samples had 10(7) to 10(8) bacteria per gram (dry weight), which were metabolically active as shown by respiration of uniformly labeled D-[(14)C]glucose. From this study it cannot be determined whether these organisms in the water column and sediments constitute a functioning food web. PMID:17734142

  11. POLISH ANTARCTIC EXPEDITION AT ARCTOWSKI POLISH STATION (KING GEORGE ISLAND, SOUTH SHETLAND ISLANDS, ANTARCTICA)

    Microsoft Academic Search

    Piotr Angiel

    2008-01-01

    This paper presents the scope of geographical research conducted at Arctowski Station during the 30 th Polish Antarctic Expedition. The research included meteorological, climatological, geomorphological and glaciological issues. During the expedition, research was conducted on sandur sediments on the outwash plain of Sphinx Glacier, the size of the aeolian transport, intensity of periglacial phenomena, and the way in which environmen-

  12. Ozone profile measurements of McMurdo Station, Antarctica, during the spring of 1987

    Microsoft Academic Search

    D. J. Hofmann; J. W. Harder; J. M. Rosen; J. V. Hereford; J. R. Carpenter

    1989-01-01

    Ozone and temperature profiles were measured in 50 balloon flights at McMurdo Station (78 deg S) during the spring of 1987. Compared to similar data obtained in 1986, stratospheric temperatures were lower and the spring time Antarctic ozone reduction was greater in magnitude, extended to higher altitude, and proceeded at a higher rate in 1987. Ozone partial pressures reached values

  13. Ice velocity from static GPS observations along the transect from Zhongshan station to Dome A, East Antarctica

    NASA Astrophysics Data System (ADS)

    Shengkai, Zhang; Dongchen, E.; Zemin, Wang; Yuansheng, Li; Bo, Jin; Chunxia, Zhou

    Dome A, the highest point on the Antarctic ice sheet at just over 4000 m a.s.l., is located near the centre of East Antarctica. Chinese National Antarctic Research Expeditions have studied icesheet dynamics and mass balance along a traverse route from Zhongshan station to Dome A during the austral summers from 1996/97 to 2004/05. Nineteen GPS sites were occupied on at least two occasions at approximately 50 km intervals. The purpose of the surveys was to provide accurate ice-dynamics data. A dual-frequency GPS receiver was used and each site was occupied for 1-12 hours. GPS data were processed using GAMIT/GLOBK software, and horizontal accuracies were within 0.1 m. Repeat GPS measurements provided ice velocities. The horizontal surface ice velocities increase from the summit of the ice sheet to the coast. In the Dome A area, the velocities are <10 m a-1; in the plateau area, velocities range from 8 to 24 m a-1 and reach about 98.2 m a-1 at a site (LT980) near the coast. The flow directions are roughly perpendicular to the ice-sheet surface elevation contours, primarily toward the Lambert Glacier basin.

  14. Calibration and Validation of Airborne LiDAR at McMurdo Station, Antarctica for Operation IceBridge

    NASA Astrophysics Data System (ADS)

    Sonntag, J. G.

    2014-12-01

    Airborne LiDAR flight operations based at McMurdo Station, Antarctica, present unusual challenges for calibrating and validating the sensor measurements at the level of a few centimeters. NASA's Airborne Topographic Mapper (ATM) team prefers to perform regular, near-daily calibrations of range and angular biases of our sensor for the lengthy field deployments typical for Operation IceBridge (OIB). For the fall 2013 OIB deployment to McMurdo, we had to adapt our usual technique of regular overflights of an independently-surveyed airport parking ramp to deal with the fact that the McMurdo airfield was located on tidally-influenced sea ice, and that very few nearby durable surfaces were free of variable-depth snow during the OIB deployment. We detail our approach for dealing with these challenges, which included multiple GPS/vehicle surveys of the sea ice runway to quantify surface changes due to grooming operations, combined with GPS tide-gauge measurements of the runway's tidal motion. We also conducted a remote GPS/vehicle survey of a mostly snow-free road on Black Island, and included both sites during near-daily overflights with the ATM. We discuss the quantitative results of these surveys and the associated ATM overflights, and present conclusions for future deployments. Finally we discuss a related validation effort in which we compare ATM results from overflights of snow-free areas in the Dry Valleys with ATM surveys of the same area from a 2001 effort there.

  15. Ozone profiles at McMurdo Station, Antarctica during he spring of 1993; record low ozone season

    SciTech Connect

    Johnson, B.J.; Deshler, T.; Zhao, R. [Univ. of Wyoming, Laramie, WY (United States)] [Univ. of Wyoming, Laramie, WY (United States)

    1995-02-01

    Record low ozone was measured by balloon-borne ozonesondes (40 flights) at McMurdo Station, Antarctica (78 deg S) during the 1993 austral spring. Total column ozone declined by 55% from an initial 275 Dobson Units (DU) on 30 August to a minimum of 130 +/- 7 DU on 2 October. Ozone within the 12-20 km showed a 95% decrease from an initial 138 DU in August to a record low 7 DU on 19 October. Probable cause of the 1993 record low ozone, based on balloon-borne observations at McMurdo include: the presence of the Pinatubo volcanic aerosol layer between 11 and 16 km (though decreased from the 1992 season); a colder than normal stratosphere over McMurdo (183 K minimum); and a relatively stable polar vortex which delayed the intrusion of high levels of ozone from outside the polar vortex wall until after 22 October. These conditions provided an optimum environment for the formation of polar stratospheric clouds (PSCs), essential to the heterogeneous chemistry that subsequently leads to the catalytic destruction of ozone by reactive chlorine.

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

    PubMed

    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

    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

  17. Geological structures deduced from airborne geophysical surveys around Syowa Station, Antarctica

    NASA Astrophysics Data System (ADS)

    Nogi, Y.; Jokat, W.; Kitada, K.; Steinhage, D.

    2012-12-01

    The area around Syowa Station, the Japanese Antarctic station in Lutzow-Holm Bay, is widely considered to be a junction of the Africa, India, Madagascar, and Antarctic continents, according to the reconstruction model of Gondwana. This area is key to investigating the formation of Gondwana. Joint Japanese-German airborne geophysical surveys were conducted around Syowa Station in January 2006 to reveal the tectonic evolution contributing to the formation of Gondwana in this area. Ice radar, magnetic, and gravity data were obtained from onshore areas. Several characteristic features that may be related to the tectonic evolution of Gondwana were inferred primarily from magnetic anomalies and from gravity anomalies and bedrock topography. The boundaries of the Lutzow-Holm Complex, the Yamato-Belgica Complex, and the Western Rayner Complex are defined, but the inland extension of the boundary between the Lutzow-Holm and the Yamato-Belgica Complexes is unknown south of 71S. The main geological structural trends of the Lutzow-Holm Complex derived from magnetic anomalies are NW-SE and are concordant with the geological results in the coastal region. However, nearly NE-SW-trending magnetic anomalies cut across the NW-SW magnetic anomaly trends, and the NE-SW right lateral strike-slip faults are deduced from the magnetic and the gravity anomaly data in the Lutzow-Holm Complex. The Lutzow-Holm Complex is divided into four blocks based on the estimated strike-slip faults. The strike-slip faults were possibly generated during a younger stage of Pan-African orogeny, after the formation of NW-SE-striking geological structures. These results provide new constraints for the formation of Gondwana.

  18. Spatial-temporal dynamics of chemical composition of surface snow in East Antarctica along the Progress station-Vostok station transect

    NASA Astrophysics Data System (ADS)

    Khodzher, T. V.; Golobokova, L. P.; Osipov, E. Yu.; Shibaev, Yu. A.; Lipenkov, V. Ya.; Osipova, O. P.; Petit, J. R.

    2014-05-01

    In January of 2008, during the 53rd Russian Antarctic Expedition, surface snow samples were taken from 13 shallow (0.7 to 1.5 m depth) snow pits along the first tractor traverse from Progress to Vostok stations, East Antarctica. Sub-surface snow/firn layers are dated from 2.1 to 18 yr. The total length of the coast to inland traverse is more than 1280 km. Here we analysed spatial variability of concentrations of sulphate ions and elements and their fluxes in the snow deposited within the 2006-2008 time interval. Anions were analysed by high-performance liquid chromatography (HPLC), and the determination of selected metals, including Na, K, Mg, Ca and Al, was carried out by mass spectroscopy with atomization by induced coupled plasma (ICP-MS). Surface snow concentration records were examined for trends versus distance inland, elevation, accumulation rate and slope gradient. Na shows a significant positive correlation with accumulation rate, which decreases as distance from the sea and altitude increase. K, Ca and Mg concentrations do not show any significant relationship either with distance inland or with elevation. Maximal concentrations of these elements with a prominent Al peak are revealed in the middle part of the traverse (500-600 km from the coast). Analysis of element correlations and atmospheric circulation patterns allow us to suggest their terrestrial origin (e.g. aluminosilicates carried as a continental dust) from the Antarctic nunatak areas. Sulphate concentrations show no significant relationship with distance inland, elevation, slope gradient and accumulation rate. Non-sea salt secondary sulphate is the most important contribution to the total sulphate budget along the traverse. Sulphate of volcanic origin attributed to the Pinatubo eruption (1991) was revealed in the snow pit at 1276 km (depth 120-130 cm).

  19. Results of SO{sub 2}, NO{sub x}, and CO monitoring at McMurdo Station, Antarctica

    SciTech Connect

    Lugar, R.M.

    1993-05-01

    This report presents the results of ambient air monitoring of carbon monoxide (CO), sulfur dioxide (SO{sub 2}), nitric oxide (NO), nitrogen dioxide (NO{sub 2}), and total oxides of nitrogen (NO{sub x}) performed during the final weeks of the 1992-1993 austral summer in the vicinity of McMurdo Station, Antarctica. Commercially available, high sensitivity ambient air gas analyzers were used to continuously measure gas concentrations at two locations over a two and a three week time period respectively. Sampling site selection, sampling procedures and quality assurance procedures used for this effort were consistent with U.S. Environmental Protection Agency guidelines for local ambient air quality networks. CO, SO{sub 2}, and NO{sub 2} concentrations measured were below the associated U.S. National Ambient Air Quality Standards. Carbon monoxide levels measured at both locations were near or below the instrument detection limit of 0.1 part per million (ppm). Hourly average SO{sub 2} concentrations ranged from below the detection limit of 1 part per billion (ppb) to a single maximum hourly average value of 60 ppb. Hourly average NO{sub 2} concentrations ranged from below the detection limit of 1 ppb to a single maximum hourly average value of 26 ppb. The impact on local air quality of ships docked at an ice pier was observed and quantified. The initial baseline effort demonstrated that site selection and sampling equipment performance were satisfactory, and provided useful data for assessing the impact of McMurdo operations on the local ambient air quality.

  20. A new French-Italian geomagnetic observatory in Dome C, Antarctica

    NASA Astrophysics Data System (ADS)

    Cafarella, L.; Zirizzotti, A.; di Mauro, D.; Schott, J. J.; Pèrès, A.; Cantin, J. M.

    2003-04-01

    Concordia is a scientific station located in the inner part of Antarctica (latitude 75° 06' S, longitude 123° 23' E, at about 3,200 m above sea level), about 950 km away from the coast. Near by the station a permanent Base is under construction and is expected to open in the year 2004. All this is the result of a join French Italian Antarctic Programs (IFRTP and PNRA respectively) effort to provide support to a growing number of scientific researches. The station is located 1.200 from Terra Nova Bay (Italy), 560 km away from Vostok Station (Russia), 1.100 Km from Dumont D'Urville (France) and Casey (Australia). During the 1998-1999 and 1999-2000 expeditions in Antarctica, some preliminary tests were carried out in order to evaluate the suitability of Dome C site for a permanent geomagnetic observatory. Two parallel data acquisition systems, each equipped with overhauser and flux-gate magnetometers were installed in two shelters at about 300 m from the Base camp. After some tests and checks, the site was considered a good site for geomagnetic investigations. The instrumentation is now in France and in Italy to prepare the instruments and the acquisition systems for the final installation that will take place during the 2004-2005 expedition.

  1. Stratosphere aerosol and cloud measurements at McMurdo Station Antarctica during the spring of 1987

    NASA Technical Reports Server (NTRS)

    Hofmann, D. J.; Rosen, J. M.; Harder, J. W.

    1988-01-01

    Measurements of stratospheric aerosols with balloonborne optical particle counters on 6 occasions at McMurdo Station (78 deg S) in the spring of 1986 indicated subsidence of the stratospheric sulfate layer during the time that the ozone hole was forming (Hofmann et al., 1988). Since dynamic models of ozone depletion involving upwelling in the spring polar vortex would suggest the opposite, we repeated the measurements with an increased frequency (about one sounding per week) in 1987. During 3 of the aerosol soundings in 1986, temperatures in the 15 to 20 km range were low enough (less than 80 C) for HNO3 to co-condense with water according to several theories of polar stratospheric cloud formation. However, particles were not observed with the characteristic size suggested by theory (approx. 0.5 microns). For this reason, it was proposed that polar stratospheric clouds may predominantly consist of large (approx. 5 to 50 microns) ice crystals at very low (approx. 10 sup 4- 10 sup 3 cm cubed) concentrations (Rosen et al., 1988). The particle counter employed would be relatively insensitive to these low concentrations. With the increased frequency of soundings in 1987, and adding additional size discrimination in the 1 to 2 micron region, this hypothesis could be verified if suitably low temperatures were encountered.

  2. Extremely low N2O concentrations in the springtime stratosphere at McMurdo Station, Antarctica

    NASA Technical Reports Server (NTRS)

    Parrish, A.; De Zafra, R. L.; Jaramillo, M.; Connor, B.; Solomon, P. M.

    1988-01-01

    Measurements have been made of stratospheric N2O using the Stony Brook millimeter-wave remote sensing spectrometer at McMurdo Station, and NO2 mixing ratios are found that are less than 1.5 at 20 km and less than 1.10 at 25 km compared to values measured during the Antarctic summer. The observed mixing ratios are also much less than those predicted by global-scale models of stratospheric chemistry and dynamics. As the NO2 signal remained very weak when McMurdo was at the edges of the ozone hole and showed no signs of recovering during October, it is concluded that the geographical and temporal extent of the region of low NO2 is comparable to or greater than that of the ozone hole. These results argue against theories that require springtime upwelling to explain the Antarctic ozone hole. It is suggested that the air in the Antarctic lower stratosphere during late winter and early spring has been subjected to considerable downward transport.

  3. Ozone profile measurements of McMurdo Station, Antarctica, during the spring of 1987

    NASA Technical Reports Server (NTRS)

    Hofmann, D. J.; Harder, J. W.; Rosen, J. M.; Hereford, J. V.; Carpenter, J. R.

    1989-01-01

    Ozone and temperature profiles were measured in 50 balloon flights at McMurdo Station (78 deg S) during the spring of 1987. Compared to similar data obtained in 1986, stratospheric temperatures were lower and the spring time Antarctic ozone reduction was greater in magnitude, extended to higher altitude, and proceeded at a higher rate in 1987. Ozone partial pressures reached values as low as 3 nbar (as compared to about 10 nbar in 1986) in the 16- to 18-km region in early and late October, down from about 150 nbar in late August. These low values suggest essentially complete removal of ozone in this region. The upper boundary of the depletion region was observed to be 2-3 km higher than in 1986, extending to altitudes as high as 24 km in mid-September. When averaged over September, the ozone mixing ratio at 18 km decayed with a half-life of only 12.4 days, as compared to about 28 days in 1986. Adiabatic vertical motions over 1- to 2-km intervals between 12 and 20 km with consequent ozone reductions were observed in association with the formation of nacreous clouds, indicating these to be rare events on a local scale probably associated with mountain lee waves.

  4. Ozone profile measurements at McMurdo Station, Antarctica, during the spring of 1987

    SciTech Connect

    Hofmann, D.J.; Harder, J.W.; Rosen, J.M.; Hereford, J.V.; Carpenter, J.R. (Univ. of Wyoming, Laramie (United States))

    1989-11-30

    Ozone and temperature profiles were measured in 50 balloon flights at McMurdo Station (78{degree}S) during the spring of 1987. Compared to similar data obtained in 1986, stratospheric temperatures were lower and the springtime Antarctic ozone reduction was greater in magnitude, extended to higher altitude, and proceeded at a higher rate in 1987. Ozone partial pressures reached values as low as 3 nbar (as compared to about 10 nbar in 1986) in the 16- to 18-km region in early and late October, down from about 150 nbar in late August. These low values suggest essentially complete removal of ozone in this region. The upper boundary of the depletion region was observed to be 2-3 km higher than in 1986, extending to altitudes as high as 24 km in mid-September. When averaged over September, the ozone mixing ratio at 18 km decayed with a half-life of only 12.4 days, as compared to about 28 days in 1986. Adiabatic vertical motions over 1- to 2-km intervals between 12 and 20 km with consequent ozone reductions were observed in association with the formation of nacreous clouds, indicating these to be rare events on a local scale probably associated with mountain lee waves.

  5. Ozone profile measurements at McMurdo Station Antarctica during the spring of 1987

    NASA Technical Reports Server (NTRS)

    Hofmann, D. J.; Harder, J. W.; Rosen, J. M.; Hereford, J.; Carpenter, J. R.

    1988-01-01

    During the Antarctic spring of 1986, 33 ozone soundings were conducted from McMurdo Station. These data indicated that the springtime decrease in ozone occurred rapidly between the altitudes of 12 and 20 km. During 1987, these measurements were repeated with 50 soundings between 29 August and 9 November. Digital conversions of standard electrochemical cell ozonesondes were again employed. The ozonesonde pumps were individually calibrated for flow rate as the high altitude performance of these pumps have been in question. While these uncertainties are not large in the region of the ozone hole, they are significant at high altitude and apparently resulted in an underestimate of total ozone of about 7 percent (average) as compared to the Total Ozone Mapping Spectrometer (TOMS) in 1986, when the flow rate recommended by the manufacturer was used. At the upper altitudes (approx. 30 km) the flow rate may be overestimated by as much as 15 percent using recommended values (see Harder et al., The UW Digital Ozonesonde: Characteristics and Flow Rate Calibration, poster paper, this workshop). These upper level values are used in the extrapolation, at constant mixing ratio, required to complete the sounding for total ozone. The first sounding was on 29 August, prior to major ozone depletion, when 274 DU total ozone (25 DU extrapolated) was observed. By early October total ozone had decreased to the 150 DU range; it then increased during mid-October owing to motion of the vortex and returned to a value of 148 DU (29 DU extrapolated) on 27 October.

  6. Observation of atmospheric minor constituents by FTIR at Syowa Station, Antarctica

    NASA Technical Reports Server (NTRS)

    Makino, Y.; Muramatsu, H.; Kawaguchi, S.; Yamanouchi, T.; Tanaka, M.; Ogawa, T.

    1985-01-01

    As a part of the Antarctic MAP activity, a ground-based spectroscopic observation of atmospheric infrared transmission was started at Syowa station (69 deg 00'S, 39 deg 35'E) in March 24, 1983. Observations of sunlight as a radiation source were made with a Fourier transform infrared spectrometer having a maximum path difference of 80 mm and an apodized FWHM resolution of approx. 0.12/cm. In routine operation through the year, the resolution of approx. 0.8/cm was applied for economy of data-processing time. The 408 spectra for 72 days were obtained in about 10 months until January 23, 1984. From the absorption features revealed in the spectra over the wave number range of 500 to 7500/cm, a preliminary estimate of N202 gamma sub 1 band absorption was attempted. An apparent transmittance was defined at the wave number 2576/cm, where the absorption by N20 molecules affected the observed intensity strongly. A ray-tracing technique and a line-by-line calculation with a model atmosphere and the AFGL atmospheric absorption line parameters compilation were applied to the calculation of the synthetic spectra.

  7. VHF radar observation of the middle atmosphere at Syowa Station, Antarctica

    NASA Technical Reports Server (NTRS)

    Igarashi, K.; Ogawa, T.; Tanaka, T.; Kuratani, Y.; Fujii, R.; Hirasawa, T.

    1985-01-01

    The newly developed pulsed Doppler radars with 50 and 112 MHz were installed at Syowa Station (69 deg 00'S, 39 deg 35'E geographic; 70.0 deg S, 80.2 deg E geomagnetic) in 1982 and 1983, respectively. They have the nominal peak power of 15 kW; the narrow antenna beams (4 deg in the horizontal plane) in two different directions (approximately geomagnetic south and geographic south with a crossing angle of about 33 deg), the three operation modes (spectrum, double-pulse and meteor mode). The radars were designed to measure the intensity and Doppler velocity of auroral radar echoes due to the 3- and 1.34-m irregularities appearing often in the disturbed E region and also to detect the meteor echoes in the 80 to 100 km altitudes, thereby to clarify how the middle atmosphere in the polar region behaves in response to the energy input from the magnetosphere, especially during a substorm. Some initial results obtained through the radar operation during 1982 to 1983 are presented to show that this system is useful for continuous monitoring of the lower auroral ionosphere.

  8. The ESA-NASA 'CHOICE' Study: Winterover at Concordia Station, Interior Antarctica, as an Analog for Spaceflight-Associated Immune Dysregu1ation

    NASA Technical Reports Server (NTRS)

    Crucian, Brian E,; Feuerecker, M.; Salam, A. P.; Rybka, A.; Stowe, R. P.; Morrels, M.; Mehta, S. K.; Quiriarte, H.; Quintens, Roel; Thieme, U.; Kaufmann, I.; Baatout, D. S.; Pierson, D. L.; Sams, C. F.; Chouker, A.

    2011-01-01

    For ground-based space physiological research, the choice of analog must carefully match the system of interest. Antarctica winter-over at the European Concordia Station is potentially a ground-analog for spaceflight-associated immune dysregulation (SAID). Concordia missions consist of prolonged durations in an extreme/dangerous environment, station-based habitation, isolation, disrupted circadian rhythms and international crews. The ESA-NASA CHOICE study assess innate and adaptive immunity, viral reactivataion and stress factors during Concordia winter-over deployment. To date, not all samples have been analyzed. Here, only data will be preliminary presented for those parameters where sample/data analysis is completed (i.e., Leukocyte subsets, T cell function, and intracellular/secreted cytokine profiles.)

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

    PubMed

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

    2007-09-20

    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 this work sediment and soil were sampled in two consecutive summer Antarctic expeditions at Potter Cove and peninsula, in the vicinity of Jubany Station (South Shetland Islands). Two- and 3-ring PAHs (methylnaphthalene, fluorene, phenanthrene and anthracene) were the main compounds found in most sites, although total PAH concentrations showed relatively low levels compared with other human-impacted areas in Antarctica. Pattern distribution of PAHs observed in samples suggested that low-temperature combustion processes such as diesel motor combustion and open-field garbage burning are the main sources of these compounds. An increase in PAH concentrations was observed from surface to depth into the active soil layer except for a unique sampling site where a fuel spill had been recently reported and where an inverted PAH concentration gradient was observed. The highest level was detected in the upper layer of permafrost followed by a sharp decrease in depth, showing this layer is acting as a barrier for downward PAH migration. When PAH levels in soil from both sampling programs were compared a significant decrease (p<0.01) was observed in summer 2005 (range at 75-cm depth: 12+/-1-153+/-22 ng/g) compared to summer 2004 (range at 75-cm depth: 162+/-15-1182+/-113 ng/g) whereas concentrations in surface sediment collected nearby the station PAHs increased drastically in 2005 (range: 36+/-3-1908+/-114 ng/g) compared to 2004 (range: 28+/-3-312+/-24 ng/g). Precipitation regime and water run off suggest that an important wash out of soil-PAHs occurred during the interval time between samplings. Results showed that the present PAH contamination level of Jubany Station is relatively low compared to other reported cases in Antarctica but also suggests that an increase in rain and in thawing processes caused by the global warming could result in an important soil-associated PAH mobilization with unpredictable consequences for the biota of Potter Cove. PMID:17570467

  10. Several-fold enhancement of biologically effective ultraviolet radiation levels at McMurdo Station, Antarctica during the 1990 ozone 'hole'

    NASA Astrophysics Data System (ADS)

    Stamnes, Knut; Jin, Zhonghai; Slusser, James; Booth, Charles; Lucas, Timothy

    1992-05-01

    Spectral measurements of biologically relevant radiation at McMurdo Station, Antarctica reveal ultraviolet (UV) irradiance levels at 305 nm in October exceeding by a factor between 3 and 6 'normal' values expected for undepleted ozone levels. This enhancement is directly related to the ozone depletion. The column abundance of stratospheric ozone derived from these measurements was as low as 145 Dobson Units (DU) in October, 1990. This is more than a factor of 2 lower than the value at solstice, and 100 DU less than in October, 1988. The dose rate for damage to the DNA molecule based on Setlow's action spectrum and UV radiation measured at noon is well above normal levels most of the time between October 1 and December 5 and is as much as three times the normal value for a few days at the end of October.

  11. The state of permafrost surrounding "Gabriel de Castilla" Spanish Antarctic Station (Deception Island, Antarctica): Studying the possible degradation due to the infrastructures heating effect.

    NASA Astrophysics Data System (ADS)

    Recio, Cayetana; Ángel de Pablo, MIguel; Ramos, MIguel; Molina, Antonio

    2015-04-01

    Permafrost degradation is one of the effects of the global warming. Many studies reveal the increase of active layer and reduction on permafrost table thickness, also in Antarctica. However, these trends on permafrost can be accelerated by the human activities, as the heating produced by the Antarctic stations infrastructures when they are not properly isolated from the ground. In Deception island, South Shetland Archipelago, we started 3 years ago a monitoring program at the 26 years old "Gabriel de Castilla" Spanish Antarctic Station (SAS), It is focused on charactering the state of permafrost, since in the coastal scarps at tens of meters from the station an increase on erosion had been detected. Although the main cause of the erosion of this coastal volcanoclastic materials is the 2 meters thick icefield which forms during the winter in the inner sea of this volcanic island, we want to detect any possible contribution to the coastal erosion caused by the permafrost degradation related to the SAS presence. We present our preliminary analysis based on three years of continuous ground temperature data, monitored at a shallow borehole (70 cm deep) in the SAS edge, together with the active layer thickness measured around the station and their vicinities in two thawing seasons. We complete this study with the analysis of the continuous temperature data taken inside the SAS and the air and ground temperatures below the station, acquired during the last Antarctic Campaign (December 2014-February 2015). These preliminary results are fundamental 1) to discard any contribution from the SAS presence, and to help to improve its thermal isolation, 2) to help improve our knowledge about the thermal state of permafrost in the area, and 3) to help to understand the causes of the coastal erosion in the volcanic Deception Island.

  12. The ESA-NASA CHOICE Study: Winterover at Concordia Station, Interior Antarctica, A Potential Analog for Spaceflight-Associated Immune Dysregulation

    NASA Technical Reports Server (NTRS)

    Crucian, B. E.; Stowe, R. P.; Mehta, S. K.; Quiriarte, H.; Pierson, D L.; Sams, C. F.

    2010-01-01

    For ground-based space physiological research, the choice of terrestrial analog must carefully match the system of interest. Antarctica winter-over at the European Concordia Station is potentially a superior ground-analog for spaceflight-associated immune dysregulation (SAID). Concordia missions consist of prolonged durations in an extreme/dangerous environment, station-based habitation, isolation, disrupted circadian rhythms and international crews. The ESA-NASA CHOICE study assesses innate and adaptive immunity, viral reactivation and stress factors during Concordia winterover deployment. Initial data obtained from the first study deployment (2009 mission; 'n' of 6) will be presented, and logistical challenges regarding analog usage for biological studies will also be discussed. The total WBC increased, and alterations in some peripheral leukocyte populations were observed during winterover at Concordia Station. Percentages of lymphocytes and monocytes increased, and levels of senescent CD8+ T cells were increased during deployment. Transient increases in constitutively activated T cell subsets were observed, at mission time points associated with endemic disease outbreaks. T cell function (early blastogenesis response) was increased near the entry/exit deployment phases, and production of most measured cytokines increased during deployment. Salivary cortisol demonstrated high variability during winterover, but was generally increased. A 2-point circadian rhythm of cortisol measurement (morning/evening) was unaltered during winterover. Perceived stress was mildly elevated during winterover. Other measures, including in-vitro DTH assessment, viral specific T cell number/function and latent herpesvirus reactivation have not yet been completed for the 2009 winterover subjects. Based on the preliminary data, alterations in immune cell distribution and function appear to persist during Antarctic winterover at Concordia Station. Some of these changes are similar to those observed in Astronauts, either during or immediately following spaceflight. Based on the initial immune data and environmental conditions, Concordia winterover may be an appropriate analog for some flight-associated immune changes.

  13. PRELIMINARY RESULTS OF THE PERFORMANCE OF AUTOMATIC WEATHER STATION IN THE PERPETUAL FROST CLIMATE OF EAST ANTARCTICA

    Microsoft Academic Search

    Manish Ranalkar; B. Amudha; N. T. Niyas; R. D. Vashistha

    In the year 2006-07, India Meteorological Department (IMD) expanded and upgraded its network of Automatic Weather Stations (AWS) by induction of 125 satellite linked AWS. A central receiving earth station in complete redundancy mode is also established at INSAT AWS Laboratory, IMD, Pune for reception of data through KALPANA1 (74 °E) satellite in near real time. IMD has planned to

  14. Micromorphological features of the fine earth and skeletal fractions of soils of West Antarctica in the areas of Russian Antarctic stations

    NASA Astrophysics Data System (ADS)

    Abakumov, E. V.; Gagarina, E. I.; Sapega, V. F.; Vlasov, D. Yu.

    2013-12-01

    Micromorphological features of the fine earth and skeletal fractions of soils of West Antarctica forming under different conditions of pedogenesis have been studied in the areas of Russian Antarctic stations. The processes of mineral weathering and alteration of rock fragments are more pronounced in the Subantarctic soils with better developed humification and immobilization of iron compounds under conditions of surface overmoistening. The biogenic accumulative processes in the soils of King George Island result in the appearance of initial forms of humic plasma that have not been detected in the Antarctic soils in the areas of the Russkaya and Leningradskaya stations. Humus films on mineral grains are present in the soils of King George Island, and organic plasmic material is present in the ornithogenic soils under penguin guano on Lindsey Island. High-latitude Antarctic soils may contain surface concentrations of organic matter; rock fragments are covered by iron oxides and soluble salts. The formation of amorphous organic plasma takes place in the ornithogenic soils of Lindsey Island. The microprobe analysis indicates the presence of local concentrations of organic matter and pedogenic compounds not only on the surface of rock fragments but also in the fissures inside them. This analysis has also proved the translocation of guano-derived organic substances inside rock fragments through a system of fissures in the soils of Lindsey Island and the development of a network of pores inside rock fragments in the soils of King George Island.

  15. Denaturing gradient gel electrophoresis fingerprinting of soil bacteria in the vicinity of the Chinese Great Wall Station, King George Island, Antarctica.

    PubMed

    Pan, Qi; Wang, Feng; Zhang, Yang; Cai, Minghong; He, Jianfeng; Yang, Haizhen

    2013-08-01

    Bacterial diversity was investigated in soil samples collected from 13 sites around the Great Wall Station, Fildes Peninsula, King George Island, Antarctica, using denaturing gradient gel electrophoresis (DGGE) of 16S rRNA genes. The classes alpha-, beta-, and gamma-Proteobacteria, as well as the phylum Actinobacteria, were found to be the dominant bacteria in the soils around the Great Wall Station. Although the selected samples were not contaminated by oil, a relationship between soil parameters, microbial biodiversity, and human impact was still seen. Sample sites in human impacted areas showed lower bacterial biodiversity (average H' = 2.65) when compared to non-impacted sites (average H' = 3.05). There was no statistically significant correlation between soil bacterial diversity and total organic carbon (TOC), total nitrogen, or total phosphorus contents of the soil. Canonical correlation analysis showed that TOC content was the most important factor determining bacterial community profiles among the measured soil parameters. In conclusion, microbial biodiversity and community characteristics within relatively small scales (1.5 km) were determined as a function of local environment parameters and anthropogenic impact. PMID:24520704

  16. Two-day period fluctuation of PMC occurrence over Syowa Station, Antarctica observed by a ground-based lidar and AIM satellite.

    NASA Astrophysics Data System (ADS)

    Nakamura, T.; Suzuki, H.; Tsutsumi, M.; Ejiri, M. K.; Tomikawa, Y.; Abo, M.; Kawahara, T.; Tsuda, T. T.; Nishiyama, T.

    2014-12-01

    A Rayleigh/Raman lidar system has been operated by the Japanese Antarctic Research Expedition (JARE) since February, 2011 (JARE 52nd) in Syowa Station Antarctica (69.0S, 39.5E). The lidar system consists of a pulsed Nd:YAG laser (355nm) as a transmitter and two telescopes with four photo multiplier tubes which are to detect Rayleigh scattered light from low and high atmosphere at 355 nm and N2 Raman emission at 387nm. Polar Mesospheric Cloud (PMC) was detected by the lidar at 22:30UT (+3hr for LT) on Feb 4th, 2011, the first day of a routine operation. This event was the first time to detect PMC over Syowa Station by a lidar [Suzuki et al., Ann. Geophys., 2013]. However, signal to noise ratio (SNR) of the PMC event was not so good due to large shot noises from daytime background signals. Moreover, a receiver system was designed mainly for nighttime observations. In this way, observation of PMC during the midnight sun, which also corresponds to most frequent PMC season, was difficult. Thus, to improve SNR of the PMC observation with the lidar during daytime, a narrow band-pass Fabry-Perot etalon unit has been developed and installed in the receiver system on Dec 2013 by JARE 55th. By using this new system, clear PMC signals were successfully detected under daylight condition during the period of summer operation of JARE55th. During this period of 53 days (from 17 Dec. 2013 to 7 Feb. 2014), only 11 days were with a clear sky and suitable for PMC observation. Thus, it was difficult to study temporal variations on a PMC activity only by using the lidar data. Fortunately, NASA's AIM satellite had passed near Syowa Station and provided with complimentary PMC data during observation gap of the lidar. By combining our lidar data with the AIM/CIPS data, nearly continuous monitoring of PMC variability over Syowa Station was achieved for period between 13th and 18th in January 2014. PMC occurrence with an interval of two days over Syowa Station during the period was clearly confirmed. Co-located MF radar also showed clear two days fluctuation in horizontal wind velocities around PMC altitude during the same period. In this presentation, we will discuss the cause of the two-day oscillation found in PMC occurrence and horizontal wind velocity. In particular, two-day planetary wave will be quantitatively investigated as a potential cause of the fluctuation.

  17. Linking the Annual Variation of Snow Radar-derived Accumulation in West Antarctica to Long-term Automatic Weather Station Measurements

    NASA Astrophysics Data System (ADS)

    Feng, B.; Braaten, D. A.; Gogineni, P.; Paden, J. D.; Leuschen, C.; Purdon, K.

    2013-12-01

    Understanding the snow accumulation rate on polar ice sheets is important in assessing mass balance and ice sheet contribution to sea level rise. Measuring annual accumulation on a regional scale and extending back in time several decades has been accomplished using the Center for Remote Sensing of Ice Sheets (CReSIS) Snow Radar on the NASA DC-8 that is part of NASA's Ice-Bridge project. The Snow Radar detects and maps near-surface internal layers in polar firn, operating from 2- 6 GHz and providing a depth resolution of ~4 cm. During November 2011, Snow Radar data were obtained for large areas of West Antarctica, including a flight segment that passed within ~70 km of Byrd Station (80°S, 119°W). Byrd Station has a very long automatic weather station (AWS) record, extending from present to 1980, with 3 relatively brief gaps in the record. The AWS data for Byrd Station were obtained from the Antarctic Meteorological Research Center (AMRC) at the University of Wisconsin. The L1B Snow Radar data products, available from the National Snow and Ice Data Center (NSIDC), were analyzed using layer picking software to obtain the depth of reflectors in the firn that are detected by the radar. These reflectors correspond to annual markers in the firn, and allow annual accumulation to be determined. Using the distance between the reflectors and available density profiles from ice cores, water equivalent accumulation for each annual layer back to 1980 is obtained. We are analyzing spatial variations of accumulation along flight lines, as well as variations in the time series of annual accumulation. We are also analyzing links between annual accumulation and surface weather observations from the Byrd Station AWS. Our analyses of surface weather observations have focused on annual temperature, atmospheric pressure and wind extremes (e.g. 5th and 95th percentiles) and links to annual snow accumulation. We are also examining satellite-derived sea ice extent records for the Bellingshausen and Amundsen seas sector (60°W-120°W) over the same 31-year time period and comparing results to annual snow accumulation. Results from this work will be presented at the meeting.

  18. Astronomy in Antarctica

    E-print Network

    Burton, Michael G

    2010-01-01

    Antarctica provides a unique environment for astronomy. The cold, dry and stable air found above the high plateau, as well as the pure ice below, offers new opportunities across the photon & particle spectrum. The summits of the 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. Astronomy conducted includes optical, IR, THz & sub-mm, measurements of the CMBR, solar, as well as high energy astrophysics involving 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. We summarise the facets of Antarctica that are dri...

  19. Autonomous station for meteo-oceanographic data acquisition in Antarctica: prototype development and results from the first operative phase

    Microsoft Academic Search

    F. Gasparoni; G. Busetto; A. Cucinotta

    1994-01-01

    In the beginning of the nineties the Italian National Antarctic Research Program has promoted a study aimed at the definition of an advanced automatic station able to operate with one year autonomy in Antarctic waters, allowing continuous collection of meteo-oceanographic data. The main results of the study were the demonstration of the feasibility of a concept based on a moored

  20. Balloon-borne measurements of aerosol, condensation nuclei, and cloud particles in the stratosphere at McMurdo Station, Antarctica, during the spring of 1987

    NASA Technical Reports Server (NTRS)

    Hofmann, D. J.; Rosen, J. M.; Harder, J. W.; Hereford, J. V.

    1989-01-01

    Measurements of the vertical profile of particles with condensation nuclei counters and eight channel aerosol detectors at McMurdo Station, Antarctica, in 1987 verified observations made in 1986 concerning the absence of upwelling in the polar vortex and the presence of a condensation nuclei layer in conjunction with the ozone hole region. New observations of a bimodal aerosol size distribution, consisting of a large-particle mode mixed in with the small-particle sulfate mode, at temperatures below -79 C are consistent with the presence of nitric acid-water particles at low concentrations. Higher concentrations of large particles were observed in association with nacreous clouds. An unusual particle layer which contained enhanced concentrations of both the small-particle (sulfate) mode and the large-particle (nitric acid) mode was detected at temperatures below -85 C, suggesting simultaneous nucleation and growth phenomena. The vortex condensation nuclei layer was observed to form at the same time as the ozone hole, indicating that formation of the layer is triggered by photochemical processes and may be important in controlling ozone depletion above 22 km.

  1. Visible and near-ultraviolet spectroscopy at McMurdo Station, Antarctica 10: Reductions of stratospheric NO{sub 2} due to Pinatubo aerosols

    SciTech Connect

    Solomon, S.; Sanders, R.W.; Jakoubek, R.O. [NOAA, Boulder, CO (United States)] [and others] [NOAA, Boulder, CO (United States); and others

    1994-02-20

    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 NO{sub 2} were as much as 50% smaller in 1992 and 1993 than in 1990 and 1991. The measured decreases in NO{sub 2} are believed to be due to the hydrolysis of N{sub 2}O{sub 5} on the enhanced volcanic aerosols injected by the massive eruption of Mount Pinatubo in mid-1991. Such decreases in NO{sub 2} are broadly consistent with observations at other latitudes and with model calculations. However, substantially reduced NO{sub 2} was also observed during the polar day period in summer under conditions of continuous local solar illumination. The formation of the key N{sub 2}O{sub 5} intermediate and reduction of NO{sub 2} at this time of year probably occurs via two mechanisms: (1) excursions of air parcels to lower latitudes where nighttime chemistry can produce N{sub 2}O{sub 5} and (2) conversion of a small fraction of the NO{sub 3} formed during the day to N{sub 2}O{sub 5}. Model calculations show that the latter mechanism can be important in spite of the fast daytime photolysis of NO{sub 3}. 27 refs., 10 figs., 1 tab.

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

    SciTech Connect

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

    1990-11-01

    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.

  3. Casey Journalism Center on Children and Families

    NSDL National Science Digital Library

    Based at the University of Maryland, College Park, the Casey Journalism Center on Children and Families (CJC) is a nonprofit program administered by the Philip Merrill College of Journalism. The CJC is funded by the Annie E. Casey Foundation, the Freddie Mac Foundation, and a number of individual donors. The CJC provides numerous fellowship and training opportunities for new and experienced journalists, and visitors with an interest in such programs can look over their offerings in the "Fellowships/Training" section. The CJC also gives out an annual award for meritorious journalism, and visitors can read each year's winning investigative pieces on the site as well. As might be expected, the site contains a "Resources" section for working journalists who write on topics like child neglect, violence, and public support systems. Visitors to these respective areas will find links to statistical sites, brief summaries of relevant data, and links for locating experts and external resources.

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

    Microsoft Academic Search

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

    2011-01-01

    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

  5. SIAMOIS: Asteroseismology in Antarctica Beno^it MOSSER1

    E-print Network

    Demoulin, Pascal

    SIAMOIS: Asteroseismology in Antarctica Beno^it MOSSER1 & the SIAMOIS team2 1 LESIA, Observatoire-based asteroseismology project, to pursue velocity measurements from the Dome C Concordia station in Antarctica. Dome C conditions in Antarctica. The instrument will be fully automatic, with no moving parts, and it will require

  6. Characteristics of highprecipitation events in Dronning Maud Land, Antarctica

    E-print Network

    Schlosser, Elisabeth

    , Antarctica E. Schlosser,1 K. W. Manning,2 J. G. Powers,2 M. G. Duda,2 G. Birnbaum,3 and K. Fujita4 Received events at the deep ice core drilling site Kohnen Station, Dronning Maud Land, Antarctica, during precipitation events in Dronning Maud Land, Antarctica, J. Geophys. Res., 115, D14107, doi:10.1029/2009JD013410

  7. Investigating the Crust and Upper Mantle of Antarctica based on S-Wave Receiver Functions Deployed in Ice Stations

    NASA Astrophysics Data System (ADS)

    Ramirez, C.; Nyblade, A.; Hansen, S. E.; Heeszel, D.; Wiens, D. A.; Anandakrishnan, S.; Aster, R. C.; Huerta, A. D.; Shore, P.; Wilson, T. J.

    2014-12-01

    The thick ice sheets that cover over 97% of the Antarctic continent make it difficult to study its geology. Seismic and other geophysical methods are the most effective ways to obtain information in this remote location. Using the classic receiver function technique, the P-to-S (Ps) conversion from the crust-mantle boundary is often masked by the ice multiples. Although removing these multiples by computational methods has been done, S-wave receiver functions (SRF) are a viable alternative and complementary method to estimate the crustal structure using S-to-P (Sp) conversions, which do not interfere with the ice multiples. In this project, we analyzed the data from the TAMSEIS, GAMSEIS and POLENET/ANET temporary seismic deployments. Sp arrival times are observed at ~5-6s in the Transantarctic Mountains and Wilkes Basin region, ~6-8s in the Gamburtsev Mountains and Vostok Higlands, and ~3-4s in the West Antarctic Rift System (WARS) and Marie Byrd Land Dome area. We used a grid search approach, combining the Sp time with Rayleigh wave phase velocities for 18 to 30 seconds, to estimate the Moho depth at each of the ice stations in the networks. The Moho depths obtained using these Sp times ranged from 28-45km, 37-59km and 16-35km respectively for the three general areas. We stacked the SRFs for several stations regionally in an attempt to obtain a qualitative view of the upper mantle structure. Most of the regional stacks do not show clear signs of seismic velocity discontinuities in the upper mantle.

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

    SciTech Connect

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

    1990-08-20

    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.

  9. Spatiotemporal variations of monocarboxylic acids in snow layers along a transect from Zhongshan Station to Dome A, eastern Antarctica

    NASA Astrophysics Data System (ADS)

    Li, Chuanjin; Xiao, Cunde; Shi, Guitao; Ding, Minghu; Kang, Shichang; Zhang, Lulu; Hou, Shugui; Sun, Bo; Qin, Dahe; Ren, Jiawen

    2015-05-01

    The spatiotemporal distributions of formate and acetate in snow layers along a transect from Zhongshan Station to Dome A are presented here. The mean concentrations of mono-carboxylic acids in summer surface snow layers were 2.93 ± 1.72 ng g- 1 and 10.07 ± 5.87 ng g- 1 for formate and acetate, respectively. In the snow pit samples, the concentrations varied between 0.47 ± 0.14 ng g- 1 and 3.12 ± 4.24 ng g- 1 for formate and between 5.31 ± 1.55 ng g- 1 and 13.29 ± 4.64 ng g- 1 for acetate. Spatially, the concentrations of both acids featured negative trends with increasing elevation and distance inland for the initial 600 km of the transect, which implies that marine sources from the coastal oceans dominate the acid supply. Different distribution styles of the acids in the interior section (600-1248 km) suggest that different source region and transporting mechanism may be responsible for the acid deposition in the interior regions. Seasonal variations in the amounts of acid in a coastal snow pit (29-A) indicate higher values in the summer and lower amounts in the winter. An enlarged source region and intensified production and transport mechanisms were primarily responsible for the higher values in summer. Longer records from the interior snow pits (29-L and 29-M) indicate elevated values in the 1970s and lower values in the 1980s and early 1990s. The increases in the mono-carboxylic acids since 1999 in snow pit 29-L and since 2005 in snow pit 29-M were temporally coincident with Chinese expedition activities in the area, suggesting that human activities were responsible for the increases in the acid load during recent decades.

  10. Proposed Casey`s Pond Improvement Project, Fermi National Accelerator Laboratory

    SciTech Connect

    NONE

    1995-05-01

    The U.S. Department of Energy (DOE) has prepared an Environmental Assessment (EA), evaluating the impacts associated with the proposed Casey`s Pond Improvement Project at the Fermi National Accelerator Laboratory (Fermilab) in Batavia, Illinois. The improvement project would maximize the efficiency of the Fermilab Industrial Cooling Water (ICW) distribution system, which removes (via evaporation) the thermal load from experimental and other support equipment supporting the high energy physics program at Fermilab. The project would eliminate the risk of overheating during fixed target experiments, ensure that the Illinois Water Quality Standards are consistently achieved and provide needed additional water storage for fire protection. Based on the analysis in the EA, the DOE has determined that the proposed action does not constitute a major Federal action significantly affecting the quality of the human environment, within the meaning of the National Environmental Policy Act (NEPA) of 1969. Therefore, the preparation of an Environmental Impact Statement is not required.

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

    Microsoft Academic Search

    S. Solomon; R. W. Sanders; H. L. Jr. Miller

    1990-01-01

    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

  12. Antarctic temperatures since the late 1950s: SAM cooling,1 background warming, and West Antarctica heating up2

    E-print Network

    Howat, Ian M.

    Antarctic temperatures since the late 1950s: SAM cooling,1 background warming, and West Antarctica to take advantage of a recently revised key temperature record from West7 Antarctica (Byrd Station.42±0.21 C decade-1 ), West Antarctica (0.21±0.10 C decade-1 ), and Antarctica as a14 whole (0.12±0.08 C

  13. Aviation Opens Antarctica

    NSDL National Science Digital Library

    The history of aviation and the history of Antarctic exploration and science are inextricably entwined. In 1929, naval aviation pioneer Richard E. Byrd, became the first person to fly over the South Pole, dropping a flag to mark his achievement and breaking the isolation of the skies over the Pole for the first time since the age of the dinosaurs. Today, more than 100 such flights annually cross the 900 miles between McMurdo Station (NSF's logistics hub in Antarctica) and the South Pole.

  14. SIAMOIS: asteroseismology in Antarctica

    NASA Astrophysics Data System (ADS)

    Mosser, B.; Buey, T.; Catala, C.; Appourchaux, T.; Charpinet, S.; Mathias, Ph.; Maillard, J. P.; Siamois Team

    2009-07-01

    SIAMOIS is a ground-based asteroseismology project, to pursue velocity measurements from the Dome C Concordia station in Antarctica. The scientific program of SIAMOIS is based on the very precise asteroseismic observation of nearby bright targets, focussing on the observations of solar-like oscillations in solar-like stars. Spectrometric observations with SIAMOIS will be able to detect l=3 oscillation modes that cannot be analyzed with space-borne photometric observations. The Doppler data, less affected by the stellar activity noise, will yield a more precise mode structure inversion, thus a high-precision determination of the stellar interior structure. The benefit of precise Doppler observations of nearby targets, with addition of interferometric and high-resolution spectrometric measurements, will allow us to investigate in detail the physical laws governing the stellar interior structure and evolution. Dome C appears to be the ideal place for ground-based asteroseismic observations as it is capable of delivering a duty cycle as high as 90% during the three-month long polar night. This duty cycle, a crucial point for asteroseismology, is comparable to space-borne observations. The SIAMOIS concept is based on Fourier Transform interferometry, which leads to a small instrument designed and developed for the harsh conditions in Antarctica. The instrument will be fully automatic, with no moving parts, and it will require only a very simple initial set up in Antarctica.

  15. Trends in mucosal immunity in Antarctica during six Australian winter expeditions

    Microsoft Academic Search

    J Lynn Francis; Maree Gleeson; Desmond J Lugg; Robert L Clancy; Jeff M Ayton; Kevin Donovan; Christine A McConnell; Trevor R Tingate; Bruce Thorpe; Anne Watson

    2002-01-01

    The mucosal immune status of Australian Antarctic personnel was monitored during six wintering expeditions at two Australian Antarctic Research Stations, Casey in 1992, 1993, 1994, and Mawson in 1992, 1995, 1996. Salivary immunoglobulin and albumin levels were examined for differences between stations and expeditions, and for monthly changes over the expedition year. Salivary IgA and IgM concentrations were on average

  16. Devotion to Jesus and Historical Investigation. A Grateful, Clarifying and Critical Response to Professor Casey 

    E-print Network

    Hurtado, Larry W

    2004-01-01

    It is obviously very gratifying to have my recent book (Lord Jesus Christ: Devotion to Jesus in Earliest Christianity, hereafter referred to as LJC) given the attention represented in Professor Casey’s commissioned review ...

  17. SIAMOIS : AN ASTEROSEISMIC NETWORK WITH 1 SITE... IN ANTARCTICA Mosser Beno^it1

    E-print Network

    Demoulin, Pascal

    SIAMOIS : AN ASTEROSEISMIC NETWORK WITH 1 SITE... IN ANTARCTICA Mosser Beno^it1 and the SIAMOIS- seismology, involving an instrument to be installed at the Dome C Concordia station in Antarctica. Dome C ap with a dedicated small 40-cm telescope. Key words: Instrumentation, Antarctica, Stars: oscilla- tions. 1

  18. A thermospheric Na layer event observed up to 140 km over Syowa Station (69.0°S, 39.6°E) in Antarctica

    NASA Astrophysics Data System (ADS)

    Tsuda, T. T.; Chu, X.; Nakamura, T.; Ejiri, M. K.; Kawahara, T. D.; Yukimatu, A. S.; Hosokawa, K.

    2015-05-01

    We report a thermospheric Na layer event (up to 140 km) observed by lidar in the night of 23-24 September 2000 at Syowa (69.0°S, 39.6°E), Antarctica. The thermospheric Na number densities were 2-9 cm-3 at 110-140 km, 3 orders of magnitude smaller than the peak density of the normal layer at 80-110 km. The thermospheric Na layers exhibited a wave-like structure with a period of 1-2 h. The colocated ionospheric/auroral observations showed sporadic E layers over Syowa through the night and an enhancement of the ionospheric/auroral activity around south side of Syowa at the event beginning. Adopting the theory by Chu et al. (2011), we hypothesize that the thermospheric Na layers are neutralized from converged Na+ layers. An envelope calculation shows good consistency with the observations.

  19. Visible and near-ultraviolet spectroscopy at McMurdo Station, Antarctica 9. Observations of OClO from April to October 1991

    Microsoft Academic Search

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

    1993-01-01

    The first spectroscopic measurements of chlorine dioxide throughout Antarctic fall, winter, and spring were carried out at McMurdo Station during April to October 1991. Two different observing modes were employed to extend the measurements over the broadest possible seasonal range: direct Moon measurements were used as well as observations of the scattered light from the sky at an 80° angle

  20. 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

    SciTech Connect

    Solomon, S.; Sanders, R.W.; Mount, G.H. (NOAA, Boulder, CO (United States)); Smith, J.P.; Perliski, L.; Miller, H.L. (Univ. of Colorado, Boulder (United States)); Keys, J.G. (National Institute for Water and Air Research, Lauder (New Zealand)); Schmeltekopf, A.L.

    1993-01-20

    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 would imply a long polar night, with associated gradual removal of NO[sub 2] and buildup of NO[sub 3] and N[sub 2]O[sub 5]. The winter observations of both species differ from such simple predictions by factors greater than 10, with the measured NO[sub 2] being far larger than predicted while the measured NO[sub 3] is much smaller than predicted. The concurrent measurement of both NO[sub 2] and NO[sub 3] strongly constrain possible solutions for these discrepancies and suggest that air parcel excursions to sunlit, lower latitudes likely take place quite regularly throughout the winter (approximately every 3-7 days). Thus the concept of an extended period of polar night as often applied in modeling studies of polar photochemistry appears inconsistent with these observations. 34 refs., 9 figs.

  1. PUBLISHED ONLINE: 23 DECEMBER 2012 | DOI: 10.1038/NGEO1671 Central West Antarctica among the most rapidly

    E-print Network

    Howat, Ian M.

    ARTICLES PUBLISHED ONLINE: 23 DECEMBER 2012 | DOI: 10.1038/NGEO1671 Central West Antarctica among changes in recent decades remain uncertain. West Antarctica has probably warmed since the 1950s Antarctica, a data set with substantial gaps. Here, we present a complete temperature record for Byrd Station

  2. Comparison of ground-based Dobson and satellite EP-TOMS total ozone measurements over Vernadsky station, Antarctica, 1996-2005

    Microsoft Academic Search

    O. Evtushevsky; G. Milinevsky; A. Grytsai; V. Kravchenko; Z. Grytsai; M. Leonov

    2008-01-01

    Total ozone content derived from version 8 of the Earth Probe Total Ozone Mapping Spectrometer (EP?TOMS) satellite data was compared with that from ground?based data obtained with the Dobson spectrophotometer no. 031 at the Ukrainian Antarctic Vernadsky station. The period of comparison is 1996–2005. The statistics for cloudy and clear sky observations are presented separately, in order to assess the

  3. Recent surface mass balance from Syowa Station to Dome F, East Antarctica: comparison of field observations, atmospheric reanalyses, and a regional atmospheric climate model

    NASA Astrophysics Data System (ADS)

    Wang, Yetang; Hou, Shugui; Sun, Weijun; Lenaerts, Jan T. M.; van den Broeke, Michiel R.; van Wessem, J. M.

    2015-02-01

    Stake measurements at 2 km intervals are used to determine the spatial and temporal surface mass balance (SMB) in recent decades along the Japanese Antarctic Research Expedition traverse route from Syowa Station to Dome F. To determine SMB variability at regional scales, this traverse route is divided into four regions, i.e., coastal, lower katabatic, upper katabatic and inland plateau. We also perform a regional evaluation of large scale SMB simulated by the regional atmospheric climate model versions 2.1 and 2.3 (RACMO2.1 and RACMO2.3), and the four more recent global reanalyses. Large-scale spatial variability in the multi-year averaged SMB reveals robust relationships with continentality and surface elevation. In the katabatic regions, SMB variability is also highly associated with surface slope, which in turn is affected by bedrock topography. Stake observation records show large inter-annual variability in SMB, but did not indicate any significant trends over both the last 40 years for the coastal and lower katabatic regions, and the last 20 years record for the upper katabatic and inland plateau regions. The four reanalyses and the regional climate model reproduce the macro-scale spatial pattern well for the multi-year averaged SMB, but fail to capture the mesoscale SMB increase at the distance interval ~300 to ~400 km from Syowa station. Thanks to the updated scheme in the cloud microphysics, RACMO2.3 shows the best spatial agreement with stake measurements over the inland plateau region. ERA-interim, JRA-55 and MERRA exhibit high agreement with the inter-annual variability of observed SMB in the coastal, upper katabatic and inland plateau regions, and moderate agreement in the lower katabatic region, while NCEP2 and RACMO2.1 inter-annual variability shows no significant correlation with the observations for the inland plateau region.

  4. Discovery and exploration of Antarctica

    SciTech Connect

    Craddock, C.

    1987-05-01

    The continent of Antarctica, some 5000 mi/sup 2/ in area, lies almost wholly within the Antarctic Circle. Some ancient philosophers and cartographers postulated the existence of a southern landmass, but the concept remained untested for centuries. In 1772-1775, Captain James Cook circumnavigated the continent and crossed the Antarctic Circle, but he sighted no land and concluded that the existence of a continent was unlikely. The first definite sightings of land by American, British, and Russian ships occurred in the Antarctic Peninsula region near 1820. In 1840, parts of the coast were mapped and landings were made by American, British, and French expeditions led, respectively, by Wilkes, Ross, and d'Urville. The first systematic geological field work was conducted by the Borchgrevink expedition in 1899-1900 near Cape Adare, south of New Zealand. During the first years of the present century, major expeditions were led by such men as Nordenskiold, Scott, Shackleton, Amundsen, and Mawson, culminating in the journeys to the South Pole by Amundsen and Scott during the 1911-1912 field season. The US has sent a number of expeditions to Antarctica during the last 60 years, beginning with the Byrd Expeditions of 1928-1930 and 1933-1935 when aircraft were used extensively and a flight was made to the South Pole. These expeditions were followed by the US Antarctic Service Expedition in 1939-1941. After World War II, US activities resumed with Operation Highjump in 1946-1947, followed the next year by Operation Windmill and the Ronne Antarctic Research Expedition. As late as 1955, most of Antarctica remained poorly known geologically. The International Geophysical Year (IGY) in 1957-1958 led to the building of 48 new stations in Antarctica by 12 nations and marked the beginning of the current period of sustained research.

  5. Tsunami Observations on Hydrophones and Island Seismic Stations

    NASA Astrophysics Data System (ADS)

    Hanson, J. A.; Bowman, J. R.; Reasoner, C. L.; Shields, G.

    2007-12-01

    The tsunami generated by the great Indonesian earthquake of 26 December 2004 was recorded across a myriad of technologies, many of which had not been designed, nor expected, to record tsunami signals. We reported on the tsunami signals from this event observed at hydrophones, intended for nuclear test monitoring, and broadband seismometers that are part of the global seismic network (GSN). Our observations led us to examine more recently reported tsunamis and other historic tsunamis. The great Sumatra-Andaman earthquake (Mw 9.1) produced high-frequency (greater than 5 mHz) dispersed tsunami signals, in addition to the destructive wave, recorded by hydrophone stations offshore from Diego Garcia and Cape Leeuwin, Australia, and by many seismic stations in the Indian Ocean and on the coast of Antarctica. Dispersed energy was observed to 60 mHz. The details within the dispersed signal provided source information to which tide gauge data are insensitive. The source of high-frequency signals could be determined using event- to-station distances estimated from the dispersion. Fine structure in the tsunami signal indicated a possible secondary high-frequency source. The dispersion observations and modeling also identified individual reflector sources over basin-wide distances. Two other recent tsunamis were observed in the Indian Ocean. The 28 March 2005 earthquake (Mw 8.6) produced high-frequency tsunami waves (to 20 mHz) observed at the Diego Garcia hydrophone station and the AIS seismic station. In addition, the lower frequency, non-dispersed tsunami waves were seen at four other seismic stations. The Mw 7.7 earthquake on 17 July 2006 south of Java also generated high frequency tsunami waves (to 10 mHz). Clear, dispersed signals were observed on hydrophone stations and seismic stations at the Cocos-Keeling Islands, and Casey, Antarctica. The first arriving energy is consistent with a source located at the earthquake epicenter. However, the strongest signals at Cocos-Keeling and Diego Garcia islands arrive after the initial onset, indicating a secondary source area or strong reflections. Island seismic station data from the Pacific were examined for tsunami signals for 14 earthquakes in the circum- Pacific region between 1994 and 2003 with Mw 7.1 to 8.4 that were known to be tsunamigenic. The seismic signals were compared to tide gauge recordings when available. Tsunami signals from 0.5 mHz up to 2-8 mHz were observed at the expected arrival time on the horizontal components of low-elevation seismic stations near coastlines for eight of the 14 earthquakes. Lower amplitude signals were observed for the other six. Dispersed tsunami signals between 1 and 8 mHz were observed for two earthquakes (Mw 8.2-8.4) and were consistent with predictions. The observations suggest that seismic data could be used to complement tide gauges and ocean bottom pressure recorders for tsunami monitoring and research.

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

    NASA Astrophysics Data System (ADS)

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

    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 at meteor altitudes from 70 to 100 km. In this study, we present altitude profiles of 15-min averaged diffusion coefficients in each month, which clearly show a minimum at 80 - 85 km. The minimum appears at higher altitude during austral summer than winter, and seems to be near the lower level of two temperature minimum structure around the mesopause seen by TIMED/SABER data at high latitudes. The higher mesopause level (95-100 km) of the SABER data does not appear in our diffusion profiles probably because it is too close the limit of meaningful diffusion coefficients that can be derived from meteor decay detection. In order to understand temperature variation around the mesopause more directly, we will discuss various methods to extract temperature profiles from the diffusion profiles. We will also present monthly averaged OH and O2 airglow temperatures observed at the same site, and compare them with those derived from the meteor radar observation.

  7. Antarctica Research in the Polar Research Center of China

    NASA Astrophysics Data System (ADS)

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

    2003-12-01

    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.

  8. Antarctica Part Two

    NSDL National Science Digital Library

    2012-07-28

    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 across, and has an incredible encounter with a Leopard seal, the apex predator of Antarctica. Part 2 finds Jonathan continuing his exploration of Antarctica including an encounter with a Leopard seal. This program won a New England Emmy Award! Please see the accompanying lesson plan for educational objectives, discussion points and classroom activities.

  9. Bringing Antarctica Home

    ERIC Educational Resources Information Center

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

    2012-01-01

    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 Antarctic…

  10. Antarctica Part One

    NSDL National Science Digital Library

    2012-07-28

    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.

  11. Upper mesospheric wind structure in Antarctica

    Microsoft Academic Search

    Parmjit Singh Sehra

    1974-01-01

    UNDER a joint Indo-Soviet agreement I was the first Indian scientist to winter in Antarctica during the 17th Soviet Antarctic Expedition, 1971-73. In particular, I participated in the meteorological rocket soundings of the upper atmosphere carried out at Molodezhnaya, a station located at 67° 40'S, 45° 51'E at a height of 42 m above mean sealevel in Enderby Land, East

  12. Microzooplankton herbivory in the Ross Sea, Antarctica

    Microsoft Academic Search

    David A. Caron; Mark R. Dennett; Darcy J. Lonsdale; Dawn M. Moran; Ludmilla Shalapyonok

    2000-01-01

    Microplankton abundances and phytoplankton mortality rates were determined at six stations during four cruises spanning three seasons in the Ross Sea polynya, Antarctica (early spring, Oct.–Nov. 1996; mid-late summer, Jan.–Feb. 1997; fall, Apr. 1997; mid-late spring, Nov.–Dec. 1997). Rates of microzooplankton herbivory were measured using a modified dilution technique, as well as by examining the rate of disappearance of phytoplankton

  13. Ralf Siebenmorgen IR instrument from Antarctica (thermal) IR instruments from Antarctica

    E-print Network

    Siebenmorgen, Ralf

    Ralf Siebenmorgen IR instrument from Antarctica (thermal) IR instruments from Antarctica: what can Antarctica Atmospheric optical thickness spectrum #12;Ralf Siebenmorgen IR instrument from Antarctica Siebenmorgen IR instrument from Antarctica Paranal Dome C (30m) Atmospheric transmission #12;Ralf Siebenmorgen

  14. Incorporation of particulates into accreted ice above subglacial Vostok lake, Antarctica

    E-print Network

    Christner, Brent C.

    Incorporation of particulates into accreted ice above subglacial Vostok lake, Antarctica George of microscopic particulates in meteoric and accreted ice from the Vostok (Antarctica) ice core is assessed depth in the southern part of the lake at Vostok station by the Russian Antarctic Expedition. The top

  15. Soil microbial community and bacterial functional diversity at Machu Picchu, King George Island, Antarctica

    Microsoft Academic Search

    I. Lahav Lavian; S. Vishnevetsky; G. Barness; Y. Steinberger

    2001-01-01

    The objective of this study was to evaluate the potential contribution of the soil microbial community in the vicinity of two plant covers, Sanionia uncinata and Deschampsia antarctica, at Machu Picchu Station, King George Island, Antarctica. Soil samples were collected at the study site during the southern (pole) summer period from 0-5 cm and 5-10 cm depths, for chemical and

  16. Autophagy in Antarctica

    PubMed Central

    Teets, Nicholas M.; Denlinger, David L.

    2013-01-01

    The midge Belgica antarctica is the only insect endemic to Antarctica and has the southernmost range of any insect. In its natural environment, B. antarctica frequently faces desiccating conditions, as environmental water is frozen for up to 9 months annually. The molecular mechanisms by which B. antarctica tolerates extreme dehydration are poorly understood, but recent work from our laboratory reports genome-wide expression changes in response to extreme dehydration (~40% water loss), the first genome-scale transcriptome reported for an Antarctic animal. Among transcripts differentially regulated during dehydration, there is coordinated upregulation of numerous genes involved in autophagy, including genes responsible for autophagosome synthesis and autophagy-associated transcription factors. Also, several genes and pathways that interact with and regulate autophagy, e.g., sestrins and proteasomal genes, are concurrently upregulated. This suggests that autophagy and related processes are key elements regulating stress tolerance in this extreme environment. PMID:23380735

  17. Live from Antarctica: the Coldest, Windiest Place on Earth

    NASA Technical Reports Server (NTRS)

    1994-01-01

    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.

  18. Antarctica - Lessons for a Mars exploration program

    NASA Technical Reports Server (NTRS)

    Mckay, C. P.

    1985-01-01

    The history of exploration and the international system of control of Antarctica has often been cited as a paradigm for the exploration of space. The small isolated research stations have been used to model the psychological stresses of future space missions. In addition, the programmatic structure of the U.S. Antarctic Research Program provides several possible analogs to future Mars Programs presently under discussion. These are: (1) Continued presence; (2) Civilian, military and private sector involvement; (3) Scientific activities; (4) Risk assessment and logistical support; (5) Accessibility for non-specialists; (6) Political and strategic motivations; (7) International cooperation/competition. Survival in Antarctica is contingent on advanced technology and the active transport of supplies. The scientific exploration of this remote and barren expanse without, of course, the aid and guidance of indigenous people certainly provides one of the closest analogs available to future science activities on the Martian surface.

  19. Annual Review 2008 Gateway Antarctica

    E-print Network

    Hickman, Mark

    Annual Review 2008 Gateway Antarctica Centre for Antarctic Studies and Research #12;1 Table of Contents From the Board 2 Directors Comment 3 Gateway Antarctica 5 Research 7 PhD Candidates 27 Teaching 41 the Board As GatewayAntarctica heads into its second decade, we can reflect on 2008 as both a milestone year

  20. Practical analysis of tide gauges records from Antarctica

    NASA Astrophysics Data System (ADS)

    Galassi, Gaia; Spada, Giorgio

    2015-04-01

    We have collected and analyzed in a basic way the currently available time series from tide gauges deployed along the coasts of Antarctica. The database of the Permanent Service for Mean Sea Level (PSMSL) holds relative sea level information for 17 stations, which are mostly concentrated in the Antarctic Peninsula (8 out of 17). For 7 of the PSMSL stations, Revised Local Reference (RLR) monthly and yearly observations are available, spanning from year 1957.79 (Almirante Brown) to 2013.95 (Argentine Islands). For the remaining 11 stations, only metric monthly data can be obtained during the time window 1957-2013. The record length of the available time series is not generally exceeding 20 years. Remarkable exceptions are the RLR station of Argentine Island, located in the Antarctic Peninsula (AP) (time span: 1958-2013, record length: 54 years, completeness=98%), and the metric station of Syowa in East Antarctica (1975-2012, 37 years, 92%). The general quality (geographical coverage and length of record) of the time series hinders a coherent geophysical interpretation of the relative sea-level data along the coasts of Antarctica. However, in an attempt to characterize the relative sea level signals available, we have stacked (i.e., averaged) the RLR time series for the AP and for the whole Antarctica. The so obtained time series have been analyzed using simple regression in order to estimate a trend and a possible sea-level acceleration. For the AP, the the trend is 1.8 ± 0.2 mm/yr and for the whole Antarctica it is 2.1 ± 0.1 mm/yr (both during 1957-2013). The modeled values of Glacial Isostatic Adjustment (GIA) obtained with ICE-5G(VM2) using program SELEN, range between -0.7 and -1.6 mm/yr, showing that the sea-level trend recorded by tide gauges is strongly influenced by GIA. Subtracting the average GIA contribution (-1.1 mm/yr) to observed sea-level trend from the two stacks, we obtain 3.2 and 2.9 mm/yr for Antarctica and AP respectively, which are interpreted as the effect of current ice melting and steric ocean contributions. By the Ensemble Empirical Mode Decomposition method, we have detected different oscillations embedded in the sea-level signals for Antarctica and AP. This confirms previously recognized connections between the sea-level variations in Antarctica and ocean modes like the ENSO.

  1. Geographic names of Antarctica

    USGS Publications Warehouse

    U.S. Board on Geographic Names; Department of the Interior; Burrill, Meredith F.; Bertrand, Kenneth J.; Alberts, Fred G.

    1956-01-01

    The geographic nomenclature of Antarctica was long in need of an overall systematic treatment, objective in approach and based upon thorough examination of all the evidence. The results of such treatment over a period of about three years were presented in Geographical Names of Antarctica, Special Publication No. 86 of the Board on Geographical Names, in May 1947, two supplements to which were issued in 1949 and 1951. The continuing program since that publication has now covered most of the geographic naming in Antarctica. As research has filled in many of the previous gaps in knowledge, a number of names have been modified and minor amendments have been made in the policies. This revised publication brings together the greatly enlarged body of names officially standardized for use by the United States Government, together with new pertinent background information.

  2. UCFieldStations The University of Canterbury has

    E-print Network

    Hickman, Mark

    provided an accessible and unique environment for research on New Zealand native bird species, while of any university in New Zealand. They include: · Field stations at Kaikoura, Cass, Westport and Harihari Islands and Antarctica used by Biological Sciences and Gateway Antarctica · and New Zealand's premier

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

    NASA Astrophysics Data System (ADS)

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

    2010-12-01

    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.

  4. Antarctica's Dry Valleys

    NSDL National Science Digital Library

    ThinkTV

    2010-11-30

    In this video segment produced by ThinkTV with the Byrd Polar Research Center, a young scientist describes her journey to the remote Dry Valleys of Antarctica and her search for life under some of the most extreme conditions on Earth.

  5. 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.

  6. Gateway Antarctica's Christchurch City Council Antarctic Scholarship

    E-print Network

    Hickman, Mark

    Gateway Antarctica's Christchurch City Council Antarctic Scholarship The Christchurch City Council by Antarctica New Zealand. 1. The Scholarship will be known as the Christchurch City Council Antarctic Scholarship and administered by Gateway Antarctica, the Centre for Antarctic Studies and Research

  7. Geotechnical Appreciation of Soil and Rocks of Schirmacher Hills, East Antarctica

    Microsoft Academic Search

    R. C. PATHAK

    Indian permanent station, Maitri was constructed during Seventh (1987-88) and Eighth (1988- 89) Indian Antarctica Expeditions. A concerted effort towards geotechnical appreciation of the area was made during present Expedition by evaluating the physical and strength properties of soil and rocks around the station. These geotechnical parameters achieve significance in so far as the founda- tion, water management and waste

  8. Characterization of aerosols and pre-cursor gases over Maitri during 24th Indian Antarctica Expedition

    Microsoft Academic Search

    P. C. S. Devara; S. M. Sonbawne; K. K. Dani; S. K. Saha; P. Ernest Raj

    2011-01-01

    Within the framework of the 24th Indian Antarctica Expedition (IAE), observations of total column aerosol optical depth (AOD), ozone (TCO) and precipitable water content (TCW) using a multi-channel solar-radiometer (MICROTOPS-II: Microprocessor-controlled Total Ozone Portable Spectrometer-II), and observations of short-wave global radiative flux using a wide-band pyranometer have been carried out over the Indian Antarctica station Maitri (70.76° S, 11.74° E)

  9. Trawl catches for many fish species exhibit diel patterns (Casey and Myers,

    E-print Network

    145 Trawl catches for many fish species exhibit diel patterns (Casey and Myers, 1998. Many gadids exhibit diel changes in availability associated with vertical migration (Beamish, 1965: a comparison of diel responses to conventional sweeps and elevated sweeps Clifford H. Ryer1 (contact author

  10. CsI Time Resolution Study with Custom Built Digitizer for the KOTO Emily Casey

    E-print Network

    CsI Time Resolution Study with Custom Built Digitizer for the KOTO Experiment Emily Casey Advisor: Yau Wah Co-Reader Jiasen Ma May 12, 2012 1 Abstract The purpose of my thesis experiment is to measure the time resolution of the cesium-iodide scintillator crystals with custom built analog

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

    Microsoft Academic Search

    Neal Devins

    2009-01-01

    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

  12. The Annie E. Casey Foundation's New Futures Initiative: Strategic Planning Guide. (Revised).

    ERIC Educational Resources Information Center

    Center for the Study of Social Policy, Washington, DC.

    Information in this guide is based on published research concerning effective strategies in dealing with at-risk youth. It was written for those communities invited to develop proposals under the Annie E. Casey Foundation's New Futures Initiative in an attempt to alleviate problems that compromise American children's futures. Each of three…

  13. An Evaluation of Yellow Perch Perca flavescens Mortality in South Dakota Casey Walter Schoenebeck

    E-print Network

    An Evaluation of Yellow Perch Perca flavescens Mortality in South Dakota By Casey Walter Aid Project F-15-R, Study 1504). #12;iv Abstract An Evaluation of Yellow Perch Perca flavescens, and mortality) of common yellow perch Perca flavescens population types have been previously investigated

  14. Evaluation of the National Science Digital Library Casey Jones & Tamara Sumner

    E-print Network

    Blandford, Ann

    collections, others are developing library services, some are engaged in library research, and one large5 Evaluation of the National Science Digital Library Casey Jones & Tamara Sumner Department the National STEM Digital Library (NSDL). A pilot study based on these instruments is currently underway

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

    ERIC Educational Resources Information Center

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

    2007-01-01

    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…

  16. Princess Astrid Coast, Antarctica

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The continent of Antarctica is almost completely covered by a thick blanket of ice, punctuated only by steep mountain peaks and a handful of dry valleys. Antarctica is also ringed by a permanent ice shelf, and that is surrounded by seasonal sea ice. The image above, acquired by the Moderate-resolution Imaging Spectroradiometer (MODIS) on September 26, 2001, shows many of the types of ice found in Antarctica. At the bottom of the image is the ice of the continental glacier, which is up to 4,000 meters thick in the interior. These thick glaciers are held in place by coastal mountain ranges. Some ice does flow through the mountains, spilling onto the relatively flat land of the Princess Astrid Coast. Cold air also spills over the mountains, creating very strong and persistent 'katabatic' winds. These scour the snow off the tops of the glaciers, leaving pale blue patches of bare ice. Above the coastline is the ice shelf, which is much smoother. There, glacial ice actually floats on the sea surface. Beyond that is the chaotic surface of the sea ice, which has been solidifying all winter long. Credit: Jacques Descloitres, MODIS Land Rapid Response Team, NASA/GSFC

  17. How to Use Bee Houses for Cavity-Nesting Bees Christine Casey, Haagen-Dazs Honey Bee Haven

    E-print Network

    Ishida, Yuko

    How to Use Bee Houses for Cavity-Nesting Bees Christine Casey, Haagen-Dazs Honey Bee Haven UC Davis Department of Entomology and Nematology October 2014 Thirty percent of California's native bee fauna are solitary bees that nest above

  18. Automatic Weather Station (AWS) Lidar

    NASA Technical Reports Server (NTRS)

    Rall, Jonathan A.R.; Abshire, James B.; Spinhirne, James D.; Smith, David E. (Technical Monitor)

    2000-01-01

    An autonomous, low-power atmospheric lidar instrument is being developed at NASA Goddard Space Flight Center. This compact, portable lidar will operate continuously in a temperature controlled enclosure, charge its own batteries through a combination of a small rugged wind generator and solar panels, and transmit its data from remote locations to ground stations via satellite. A network of these instruments will be established by co-locating them at remote Automatic Weather Station (AWS) sites in Antarctica under the auspices of the National Science Foundation (NSF). The NSF Office of Polar Programs provides support to place the weather stations in remote areas of Antarctica in support of meteorological research and operations. The AWS meteorological data will directly benefit the analysis of the lidar data while a network of ground based atmospheric lidar will provide knowledge regarding the temporal evolution and spatial extent of Type la polar stratospheric clouds (PSC). These clouds play a crucial role in the annual austral springtime destruction of stratospheric ozone over Antarctica, i.e. the ozone hole. In addition, the lidar will monitor and record the general atmospheric conditions (transmission and backscatter) of the overlying atmosphere which will benefit the Geoscience Laser Altimeter System (GLAS). Prototype lidar instruments have been deployed to the Amundsen-Scott South Pole Station (1995-96, 2000) and to an Automated Geophysical Observatory site (AGO 1) in January 1999. We report on data acquired with these instruments, instrument performance, and anticipated performance of the AWS Lidar.

  19. Redescription of Stenolophus thoracicus Casey (Coleoptera, Carabidae, Harpalini), a valid species

    PubMed Central

    Bousquet, Yves; Messer, Peter W.

    2010-01-01

    Abstract Stenolophus thoracicus Casey is revalidated. The species is redescribed based on a study of the syntypes and of several conspecific specimens from eastern North America. The species differs from the other eastern species of the subgenus Agonoleptus in having the metasternum shorter and the wings reduced to tiny stubs. The dorsal habitus and median lobe of the aedeagus, along with the structures of the internal sac, are illustrated. PMID:21594130

  20. Direct gravimetric determination of aerosol mass concentration in central antarctica.

    PubMed

    Annibaldi, Anna; Truzzi, Cristina; Illuminati, Silvia; Scarponi, Giuseppe

    2011-01-01

    In Antarctica, experimental difficulties due to extreme conditions have meant that aerosol mass has rarely been measured directly by gravimetry, and only in coastal areas where concentrations were in the range of 1-7 ?g m(-3). The present work reports on a careful differential weighing methodology carried out for the first time on the plateau of central Antarctica (Dome C, East Antarctica). To solve problems of accurate aerosol mass measurements, a climatic room was used for conditioning and weighing filters. Measurements were carried out in long stages of several hours of readings with automatic recording of temperature/humidity and mass. This experimental scheme allowed us to sample from all the measurements (up to 2000) carried out before and after exposure, those which were recorded under the most stable humidity conditions and, even more importantly, as close to each other as possible. The automatic reading of the mass allowed us in any case to obtain hundreds of measurements from which to calculate average values with uncertainties sufficiently low to meet the requirements of the differential weighing procedure (±0.2 mg in filter weighing, between ±7% and ±16% both in aerosol mass and concentration measurements). The results show that the average summer aerosol mass concentration (aerodynamic size ?10 ?m) in central Antarctica is about 0.1 ?g m(-3), i.e., about 1/10 of that of coastal Antarctic areas. The concentration increases by about 4-5 times at a site very close to the station. PMID:21141836

  1. Peculiar spherules from Antarctica and their origin

    NASA Technical Reports Server (NTRS)

    Tazawa, Y.; Fujii, Y.

    1984-01-01

    Two calcium titanium oxide spherules (CTS) and an iron chromium nickel oxide one (FCN) were obtained from a segment of ice core collected at Mizuho Station, East Antarctica. An anomalous REE abundance pattern enriched in Sm by a factor of about 10 relative to the typical pattern of terrestrial perovskites was found. Subsequently, more than forty spherules from ten other depth ranges of the ice core were analyzed: (1) both CTS and FCN occur in every depth range; (2) CTS, FCN, and other are in the ratio of about 2:21 among all the analyzed spherules; (3) all of CTS show the same chemical and mineralogical characteristics as those previously obtained; (4) CTS contains some amounts of Cr and Fe, and/or FCN contains Ca and Ti; and (5) two composite particles exist among all the spherules. It is implied that CTS and FCN had originated in a common natural material and from a common natural process.

  2. Whistler observations of the plasmasphere\\/plasmapause from stations of the British Antarctic Survey

    Microsoft Academic Search

    A. J. Smith

    2001-01-01

    VLF whistler observations from Eights Station, Antarctica were crucial to the discovery and exploration of the plasmapause (“Carpenter's knee”) by Don Carpenter in the mid-1960s. The Weddell Sea sector of Antarctica is particularly well suited to such work because of the high whistler rate (conjugate to thunderstorm regions), proximity to the ground footprint of the average plasmapause, low electromagnetic noise

  3. Evaluation of the Effects of the Ultra-Violet Radiation of Antarctica on Bovine Corneas and Lenses by Raman Spectroscopy

    NASA Astrophysics Data System (ADS)

    Yamamoto, Tatsuyuki; Imura, Satoshi; Yamamoto, Naoyuki

    2010-08-01

    The Raman spectra of bovine corneas and lenses irradiated to the ultra violet radiation at Syowa station of Antarctica were observed. The bovine crystallin occurred photo-induced cataract by the exposure to the solar radiation of mid-summer at Antarctica. Photo-induced decrease of Raman signals assigned to Trp residues suggests that the structural change of crystallin is correlated with the decomposition of them. The Raman spectra of the collagen of cornea showed little change, however FT-IR measurements showed that the IamideII/IamideI decreased much by the exposure to the solar radiation of mid-summer at Antarctica.

  4. 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.

  5. Application of SAR interferometry in Grove Mountains, east Antarctica

    NASA Astrophysics Data System (ADS)

    E, Dongchen; Zhou, Chunxia; Liao, Mingsheng

    2004-02-01

    Synthetic aperture radar interferometry has been proposed as a potential technique for digital elevation model (DEM) generation, topographic mapping, and surface motion detection especially in the inaccessible areas. Grove Mountains Area locates to the southwest of Princess Elizabeth Land, inland areas of east Antarctica. The topographical map of the core area (11 x 10 KM2) was printed after the field surveying with GPS and total station was finished under the atrocious weather conditions during the 16th CHINARE (Chinese National Antarctic Research Expedition) 1999/2000. This paper will present an experimental investigation of the ERS-1/2 SAR tandem data in 1996 on DEM generation of the Grove Mountains Core Area, analyze the data processing, and compare the DEM with the actual topographic form. It is confirmed that InSAR is a very useful technique to be utilized in Antarctica, and can be used to produce more products instead of dagnerous field surveying.

  6. Whole Atmosphere Model (WAM) simulations of tides over Antarctica

    NASA Astrophysics Data System (ADS)

    Akmaev, R. A.

    2012-12-01

    Ground-based radar and optical observations of winds and temperatures have revealed a rich and variable spectrum of tidal oscillations in the mesosphere/lower thermosphere (MLT) over Antarctica, including the South Pole. Formally, polar geometry can only support large-scale oscillations with zonal wavenumbers 0 or 1. The only migrating tide that can exist here is the diurnal westward DW1. Other tidal periods project on the permitted wavenumbers, making the Pole an ideal place for studying nonmigrating oscillations such as the well documented semidiurnal westward SW1. Migrating tides still make a substantial contribution over the edges of the continent posing an identification problem for any single station on the ground. WAM simulations showing promising agreement with existing observations in amplitude, phase, and day-to-day variability of prominent tidal components over Antarctica will be presented and analyzed.

  7. Seismic imaging of the crust beneath Dronning Maud Land, East Antarctica

    Microsoft Academic Search

    Bettina Bayer; Wolfram H. Geissler; A. Eckstaller; Wilfried Jokat

    2009-01-01

    With calculations of receiver functions and modelling of a seismic refraction profile we map the depth to the Moho discontinuity beneath Dronning Maud Land (DML), East Antarctica. The crustal converted signal (Ps) is clearly observable for all stations, suggesting that the crust is separated from the mantle by a sharp Moho. We reveal spatial variations in the crustal thickness and

  8. Temporal and spatial variability of the surface energy balance in Dronning Maud Land, East Antarctica

    Microsoft Academic Search

    C. H. Reijmer; J. Oerlemans

    2002-01-01

    We present data of nine Automatic Weather Stations (AWS), which are located in Dronning Maud Land (DML), East Antarctica, since the austral summer of 1997. Potential temperature and wind speed are maximum at the sites with the steepest surface slope, i.e., at the edge of the Antarctic plateau. Specific humidity and accumulation decrease with elevation and distance from the coast.

  9. Seismic Constraints on the Mantle Viscosity Structure beneath Antarctica

    NASA Astrophysics Data System (ADS)

    Wiens, Douglas; Heeszel, David; Aster, Richard; Nyblade, Andrew; Wilson, Terry

    2015-04-01

    Lateral variations in upper mantle viscosity structure can have first order effects on glacial isostatic adjustment. These variations are expected to be particularly large for the Antarctic continent because of the stark geological contrast between ancient cratonic and recent tectonically active terrains in East and West Antarctica, respectively. A large misfit between observed and predicted GPS rates for West Antarctica probably results in part from the use of a laterally uniform viscosity structure. Although not linked by a simple relationship, mantle seismic velocities can provide important constraints on mantle viscosity structure, as they are both largely controlled by temperature and water content. Recent higher resolution seismic models for the Antarctic mantle, derived from data acquired by new seismic stations deployed in the AGAP/GAMSEIS and ANET/POLENET projects, offer the opportunity to use the seismic velocity structure to place new constraints on the viscosity of the Antarctic upper mantle. We use an Antarctic shear wave velocity model derived from array analysis of Rayleigh wave phase velocities [Heeszel et al, in prep] and examine a variety of methodologies for relating seismic, thermal and rheological parameters to compute a suite of viscosity models for the Antarctic mantle. A wide variety of viscosity structures can be derived using various assumptions, but they share several robust common elements. There is a viscosity contrast of at least two orders of magnitude between East and West Antarctica at depths of 80-250 km, reflecting the boundary between cold cratonic lithosphere in East Antarctica and warm upper mantle in West Antarctica. The region beneath the Ellsworth-Whitmore Mtns and extending to the Pensacola Mtns. shows intermediate viscosity between the extremes of East and West Antarctica. There are also significant variations between different parts of West Antarctica, with the lowest viscosity occurring beneath the Marie Byrd Land (MBL). The MBL Dome and adjacent coastal areas show extremely low viscosity (~1018Pa-s) for most parameterizations, suggesting that low mantle viscosity may produce a very rapid response to ice mass loss in this region.

  10. Solar Eclipses Observed from Antarctica

    NASA Astrophysics Data System (ADS)

    Pasachoff, Jay M.

    2013-01-01

    Aspects of the solar corona are still best observed during totality of solar eclipses, and other high-resolution observations of coronal active regions can be observed with radio telescopes by differentiation of occultation observations, as we did with the Jansky Very Large Array for the annular solar eclipse of 2012 May 20 in the US. Totality crossing Antarctica included the eclipse of 2003 November 23, and will next occur on 2021 December 4; annularity crossing Antarctica included the eclipse of 2008 February 7, and will next occur on 2014 April 29. Partial phases as high as 87% coverage were visible and were imaged in Antarctica on 2011 November 25, and in addition to partial phases of the total and annular eclipses listed above, partial phases were visible in Antarctica on 2001 July 2011, 2002 December 4, 2004 April 19, 2006 September 22, 2007 September 11, and 2009 January 26, and will be visible on 2015 September 13, 2016 September 1, 2017 February 26, 2018 February 15, and 2020 December 14. On behalf of the Working Group on Solar Eclipses of the IAU, the poster showed the solar eclipses visible from Antarctica and this article shows a subset (see www.eclipses.info for the full set). A variety of investigations of the Sun and of the response of the terrestrial atmosphere and ionosphere to the abrupt solar cutoff can be carried out at the future eclipses, making the Antarctic observations scientifically useful.

  11. Carbonaceous micrometeorites from Antarctica.

    PubMed

    Engrand, C; Maurette, M

    1998-07-01

    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

  12. Snow chemistry across Antarctica

    NASA Astrophysics Data System (ADS)

    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.

    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.

  13. Remote sensing and skywave digital communication from antarctica.

    PubMed

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

    2009-01-01

    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

  14. Discovery and exploration of Antarctica

    Microsoft Academic Search

    Craddock

    1987-01-01

    The continent of Antarctica, some 5000 mi² in area, lies almost wholly within the Antarctic Circle. Some ancient philosophers and cartographers postulated the existence of a southern landmass, but the concept remained untested for centuries. In 1772-1775, Captain James Cook circumnavigated the continent and crossed the Antarctic Circle, but he sighted no land and concluded that the existence of a

  15. Free Parking Available for Famous Idaho Potato Bowl Media Contact: Casey Jones, Executive Director, Transportation & Parking Services

    E-print Network

    Barrash, Warren

    Free Parking Available for Famous Idaho Potato Bowl Media Contact: Casey Jones, Executive Director Potato Bowl at Boise State University on Saturday, Dec. 15, can park for free in exchange for donations honoring free parking in exchange for donations include: Lincoln Ave Garage (1607 University Drive) Norco

  16. Coccinellidae (Coleoptera) of South Dakota: New State Record for Anatis lecontei Casey and Erratum to Delete Hyperaspis fimbriolata Melsheimer

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this paper, we provide collection information to add Anatis lecontei Casey to the list of South Dakota Coccinellidae based on its collection for the first time in the state. We also include an erratum to delete Hyperaspis fimbriolata Melsheimer from the list based on its mistaken inclusion in an...

  17. Phonon-polariton excitations in photonic crystals Kerwyn Casey Huang,* Peter Bienstman, John. D. Joannopoulos, and Keith A. Nelson

    E-print Network

    Fan, Shanhui

    , almost dispersionless bands below the phonon frequency T . Kuzmiak et al. postulated an explanationPhonon-polariton excitations in photonic crystals Kerwyn Casey Huang,* Peter Bienstman, John. D The incorporation of materials which exhibit transverse phonon-polariton excitations into a photonic crystal

  18. A review of the species of Geraeus Pascoe and Linogeraeus Casey found in the continental United States (Coleoptera: Curculionidae: Baridinae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The baridine weevils with a smooth inner mandibular face and unmodified antenna are reviewed for the continental U.S. Toxeres Germar 1829, a new synonym of Geraeus Pascoe 1889, is suppressed as nomen oblitum and Geraeus is conserved as nomen protectum. Pycnogeraeus Casey 1920 is a new synonym of G...

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

    ERIC Educational Resources Information Center

    Annie E. Casey Foundation, 2006

    2006-01-01

    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…

  20. Pine Island Glacier, Antarctica

    NASA Technical Reports Server (NTRS)

    2001-01-01

    This pair of MISR images of the Pine Island Glacier in western Antarctica was acquired on December 12, 2000 during Terra orbit 5246. At left is a conventional, true-color image from the downward-looking (nadir) camera. The false-color image at right is a composite of red band data taken by the MISR forward 60-degree, nadir, and aftward 60-degree cameras, displayed in red, green, and blue colors, respectively. Color variations in the left (true-color) image highlight spectral differences. In the multi-angle composite, on the other hand, color variations act as a proxy for differences in the angular reflectance properties of the scene. In this representation, clouds show up as light purple. Blue to orange gradations on the surface indicate a transition in ice texture from smooth to rough. For example, the bright orange 'carrot-like' features are rough crevasses on the glacier's tongue. In the conventional nadir view, the blue ice labeled 'rough crevasses' and 'smooth blue ice' exhibit similar coloration, but the multi-angle composite reveals their different textures, with the smoother ice appearing dark purple instead of orange. This could be an indicator of different mechanisms by which this ice is exposed. The multi-angle view also reveals subtle roughness variations on the frozen sea ice between the glacier and the open water in Pine Island Bay.

    To the left of the 'icebergs' label are chunks of floating ice. Additionally, smaller icebergs embedded in the frozen sea ice are visible below and to the right of the label. These small icebergs are associated with dark streaks. Analysis of the illumination geometry suggests that these streaks are surface features, not shadows. Wind-driven motion and thinning of the sea ice in the vicinity of the icebergs is one possible explanation.

    Recently, Robert Bindschadler, a glaciologist at the NASA Goddard Space Flight Center discovered in Landsat 7 imagery a newly-formed crack traversing the Pine Island Glacier. This crack is visible as an off-vertical dark line in the MISR nadir view. In the multi-angle composite, the crack and other stress fractures show up very clearly in bright orange. Radar observations of Pine Island Glacier in the 1990's showed the glacier to be shrinking, and the newly discovered crack is expected to eventually lead to the calving of a major iceberg.

    MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology.

  1. Let's Talk with David Nold about Safety and Wintering Over in Antarctica

    NSDL National Science Digital Library

    At this site students discover that Antarctica's winter runs from mid-February through late August and if one decides to stay, one is there for the duration since all aircraft traffic is stopped. They will also learn how research crews prepare to go it alone. This in-depth profile of a safety and health engineer offers a look at what it takes to keep an Antarctic research station running year-round. In the question and answer profile the engineer answers more than 15 questions, including why kids should know about deep sea Antarctica, what the big deal is about wintering over, and if things change drastically when the summer crew arrives. He also describes a typical workday in the winter there and explains what he misses about Antarctica when he is not there.

  2. The mantle transition zone beneath Antarctica: Evidence for thermal upwellings and hydration

    NASA Astrophysics Data System (ADS)

    Nyblade, Andrew; Emry, Erica; Hansen, Samantha; Julia, Jordi; Anandakrishnan, Sridhar; Aster, Richard; Wiens, Douglas; Huerta, Audrey; Wilson, Terry

    2015-04-01

    West Antarctica has experienced abundant Cenozoic volcanism, and it is suspected that the region is influenced by upwelling thermal plumes from the lower mantle; however this has not yet been verified, because seismic tomography results are not well resolved at mantle transition zone (MTZ) depths. We use P-wave receiver functions (PRFs) from temporary and permanent arrays throughout Antarctica, including the Antarctic POLENET, TAMNET, TAMSEIS, and GAMSEIS arrays, to explore the characteristics of the MTZ beneath the continent. We obtained PRFs for earthquakes occurring at 30-90° with Mb>5.5 using a time-domain iterative deconvolution method filtered with a Gaussian-width of 0.5 and 1.0, corresponding to frequencies less than ~0.24 Hz and ~0.48 Hz, respectively. We combine P receiver functions as single-station and as common conversion point stacks and migrate them to depth using the ak135 1-d velocity model. Results from West Antarctica suggest that the thickness of the MTZ varies throughout the region with thinning beneath the Ruppert Coast of Marie Byrd Land and beneath the Bentley Subglacial Trench and Whitmore Mountains. Also, prominent negative peaks are detected above the transition zone beneath much of West Antarctica and may be evidence for water-induced partial melt above the MTZ. Preliminary results from single-station stacks for the mantle transition zone beneath East Antarctica suggests that one section of East Antarctica, off of the South Pole may have slightly thinned transition zone. Results are forthcoming from the mantle transition zone beneath Victoria Land and the Northern Transantarctics. We propose that the MTZ beneath parts of West Antarctica and possibly also beneath one region of East Antarctica, is hotter than average, possibly due to material upwelling from the lower mantle. Furthermore, we propose that the transition zone beneath much of West Antarctica is water-rich and that upward migration of hydrated material results in formation of a partial melt layer above the MTZ.

  3. Strong-wind events and their influence on the formation of snow dunes: observations from Kohnen station, Dronning Maud Land,

    E-print Network

    Schlosser, Elisabeth

    station, Dronning Maud Land, Antarctica Gerit BIRNBAUM,1 Johannes FREITAG,1 Ralf BRAUNER,2 Gert KO¨ NIG.s.l.) on the plateau of Dronning Maud Land reveal the presence of conserved snow dunes in the firn. In situ

  4. Fecal Coliforms in Antarctica

    NSDL National Science Digital Library

    Stephen C. Nold

    2002-01-01

    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.

  5. Terrestrial Spaceflight Analogs: Antarctica

    NASA Technical Reports Server (NTRS)

    Crucian, Brian

    2013-01-01

    Alterations in immune cell distribution and function, circadian misalignment, stress and latent viral reactivation appear to persist during Antarctic winterover at Concordia Station. Some of these changes are similar to those observed in Astronauts, either during or immediately following spaceflight. Others are unique to the Concordia analog. Based on some initial immune data and environmental conditions, Concordia winterover may be an appropriate analog for some flight-associated immune system changes and mission stress effects. An ongoing smaller control study at Neumayer III will address the influence of the hypoxic variable. Changes were observed in the peripheral blood leukocyte distribution consistent with immune mobilization, and similar to those observed during spaceflight. Alterations in cytokine production profiles were observed during winterover that are distinct from those observed during spaceflight, but potentially consistent with those observed during persistent hypobaric hypoxia. The reactivation of latent herpesviruses was observed during overwinter/isolation, that is consistently associated with dysregulation in immune function.

  6. Lidar observation of the mesospheric sodium layer in Antarctica

    NASA Technical Reports Server (NTRS)

    Nomura, A.; Iwasaka, Y.; Fukunishi, H.; Hirasawa, T.; Kawaguchi, S.; Kano, T.

    1986-01-01

    The mesospheric sodium layer has been observed at Syowa Station in Antarctica during the wintering period of the 26th Japanese Antarctic Research Expedition. A lidar observation of the polar middle atmosphere at the station has been performed as a part of the Middle Atmosphere Program since 1983. At first stratospheric aerosols have been observed by the system based on a ruby laser. In 1985 a new transmitting system consisting of a tunable dye laser was added to that system to observe the sodium layer, too. The characteristics of the lidar system are given. The results of the mesospheric sodium layer observed on 42 nights during the period from March to October, 1985 are also given.

  7. CONCORDIASI, Long Duration Stratospheric Balloons over Antarctica

    NASA Astrophysics Data System (ADS)

    Cocquerez, Philippe

    2012-07-01

    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.

  8. Icebergs in the Ross Sea, Antarctica

    NASA Technical Reports Server (NTRS)

    2001-01-01

    Two large icebergs, designated B-15A and C-16, are captured in this MISR nadir camera view of the Ross Ice Shelf and Ross Sea in Antarctica. The image was acquired on December 10, 2000 during Terra orbit 5220.

    Iceberg C-16 calved off the ice shelf in late September and is nearly 50 kilometers in length. It is seen here having migrated to the vicinity of Cape Bird on Ross Island. The initial letter designation in an iceberg's name denotes the longitudinal quadrant in which it is first seen, and new icebergs sighted in that quadrant are sequentially numbered. B-15 divided from the ice shelf last March, and initially was nearly as large as the state of Connecticut. It has since broken up into several pieces, hence the final letter designation in the berg shown in this image.

    Ross Island lies between 77 and 78 degrees south latitude, and consists of several volcanic peaks, of which the still active Mt. Erebus is the tallest (3794 meters). It overlooks McMurdo Station, a U.S. research facility located near the tip of the island's Hut Point Peninsula.

    MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology.

  9. Annual variation of total ozone at Syowa Station, Antarctica

    Microsoft Academic Search

    Shigeru Chubachi

    1997-01-01

    Analysis of total ozone data from Syowa (69°S, 40°E) for the years 1982 to 1994 reveals several new features in the behavior of ozone depletion. There is no significant year-to-year trend or seasonal variation of total ozone during the polar night (June and July), and the mean value for these months provides a baseline for determining the springtime ozone decrease.

  10. Crust and Upper Mantle Structure of Antarctica from Rayleigh Wave Tomography

    NASA Astrophysics Data System (ADS)

    Wiens, D. A.; Heeszel, D. S.; Sun, X.; Chaput, J. A.; Aster, R. C.; Nyblade, A.; Anandakrishnan, S.; Wilson, T. J.; Huerta, A. D.

    2012-12-01

    We combine data from three temporary arrays of seismometers (AGAP/GAMSEIS 2007-2010, ANET/POLENET 2007-2012, TAMSEIS 2001-2003) deployed across Antarctica, along with permanent stations in the region, to produce a large scale shear velocity model of the continent extending from the Gamburtsev Subglacial Mountains (GSM) in East Antarctica, across the Transantarctic Mountains (TAM) and West Antarctic Rift System (WARS) to Marie Byrd Land (MBL) in West Antarctica. Our combined dataset consists of Rayleigh wave phase and amplitude measurements from 112 stations across the study region. We first invert for 2-D Rayleigh wave phase velocities using the two-plane wave method. These results are then inverted for shear velocity structure using crustal thicknesses derived from ambient noise tomography and teleseismic receiver functions. We refine our shear velocity model by performing a Monte Carlo simulation that explores the tradeoff between crustal thickness and upper mantle seismic velocities. The resulting model is higher resolution than previous studies (~150 km resolution length) and highlights significant differences in crustal and uppermost mantle structure between East and West Antarctica in greater detail than previously possible. East Antarctica is underlain by thick crust (reaching ~55 km beneath the GSM) and fast, cratonic lithosphere. West Antarctica is defined by thinner crust and slow upper mantle velocities indicative of its more recent tectonic activity. The observed boundary in crustal thickness closely follows the TAM front. MBL is underlain by a thicker lithosphere than that observed beneath the WARS, but slow mantle velocities persist to depths greater than 200 km, indicating a 'deep seated' (i.e. deeper than the deepest resolvable features of our model) thermal source for volcanism in the region. The slowest seismic velocities at shallow depths are observed in the Terror Rift region of the Ross Sea along an arc following the TAM front, where the most recent extension has occurred, and in another region of active volcanism. The Ellsworth-Whitmore Mountains are underlain by relatively thick crust and an intermediate thickness lithosphere, consistent with its hypothesized origin as a remnant Precambrian crustal block. We also produce upper mantle viscosity models for the study region using a temperature-dependent rheology, assuming that mantle seismic anomalies are dominated by temperature variations. Initial results closely correlate with the velocity model, with viscosities beneath West Antarctica inferred to be orders of magnitude lower than beneath East Antarctica. These viscosity results have important implications for our understanding of glacial isostatic adjustment, which is of particular interest in producing models of past and future changes in the Antarctic Ice Sheets.

  11. Snow chemistry across Antarctica N. BERTLER,1

    E-print Network

    Fischer, Hubertus

    Snow chemistry across Antarctica N. BERTLER,1 P.A. MAYEWSKI,2 A. ARISTARAIN,3 P. BARRETT,1 S by the national ITASE (International Trans-Antarctic Scientific Expedition) programmes of Australia, Brazil, China orders of magnitude across Antarctica and exhibit distinct geographical patterns. The Antarctic

  12. Cutaneous and diphtheritic avian poxvirus infection in a nestling Southern Giant Petrel ( Macronectes giganteus ) from Antarctica

    Microsoft Academic Search

    Valerie Shearn-Bochsler; D. Earl Green; Kathryn A. Converse; Douglas E. Docherty; Teresa Thiel; Heidi N. Geisz; William R. Fraser; Donna L. Patterson-Fraser

    2008-01-01

    The Southern giant petrel (Macronectes giganteus) is declining over much of its range and currently is listed as vulnerable to extinction by the International Union for the\\u000a Conservation of Nature (IUCN). Island-specific breeding colonies near Palmer Station, Antarctica, have been monitored for\\u000a over 30 years, and because this population continues to increase, it is critically important to conservation. In austral summer

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

    Microsoft Academic Search

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

    2008-01-01

    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

  14. Valley floor climate observations from the McMurdo dry valleys, Antarctica, 1986–2000

    Microsoft Academic Search

    Peter T. Doran; Christopher P. McKay; Gary D. Clow; Gayle L. Dana; Andrew G. Fountain; Thomas Nylen; W. Berry Lyons

    2002-01-01

    Climate observations from the McMurdo dry valleys, East Antarctica are presented from a network of seven valley floor automatic meteorological stations during the period 1986 to 2000. Mean annual temperatures ranged from ?14.8°C to ?30.0°C, depending on the site and period of measurement. Mean annual relative humidity is generally highest near the coast. Mean annual wind speed increases with proximity

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

    Microsoft Academic Search

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

    1986-01-01

    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

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

    Microsoft Academic Search

    A. J. Smith

    1995-01-01

    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

  17. MORPHOLOGY OF THE AQUATIC MOSSES COLLECTED IN LAKE YUKIDORI, LANGHOVDE, ANTARCTICA

    Microsoft Academic Search

    Hiroshi KANDA; Shuji OHTANI

    National Institute of Polar Research, 9-10, Kaga 1-chome, Ztabashi-ku, Tokyo 173 Abstract: Participating in the 29th Japanese Antarctic Research Expedition (JARE-29, 1987-1989), the authors collected aquatic mosses growing in Lake Yukidori, Langhovde near Syowa Station, East Antarctica. The moss specimens examined are mostly submerged forms of Bryum pseudotriquetrum (HEDw.) GAERTN., MEYER et SCHERB. which is usually characterized by elongate stems,

  18. Dry Valleys of Antarctica: Limnoir

    NSDL National Science Digital Library

    Karen Cozzetto

    This journal account describes the work of the limnology team on the lakes in the dry valleys of Antarctica in the form of a short story. It describes the long-term monitoring of lake water and organisms in order to create a picture of the ecology of the lakes. The account points out that galcial meltwater is essentially the only source of water and nutrients to the lakes and describes some of the specialized equipment used for sampling and testing. It also describes some of the organisms (extremophiles) which have adapted to the harsh conditions in the lakes.

  19. Station Models

    NSDL National Science Digital Library

    Mr. Ertl

    2007-11-03

    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 ...

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

    SciTech Connect

    White, G.J.

    1996-08-01

    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.

  1. Concentration and isotope ratio of sulfur species in snow along the route to Dome Fuji, Antarctica

    NASA Astrophysics Data System (ADS)

    Hirabayashi, M.; Motoyama, H.

    2014-12-01

    Snow ice sample in Antarctica contains particulate matter. Particulates originate from continent, volcano, sea, space, and organism. Methanesulfonate ion and sulfate ion are major sulfur compounds packed in snow ice in Antarctica. The isotopic ratio of an element reflects the origin and the history of the particle matter. Since the isotopic ratio of sulfur species depends on the source, the information about the source contribution of particulate matter can be estimated by analyzing the isotopic ratios of sulfur species. In this research, concentrations of sulfur species and isotopic ratios of sulfur species in snow collected on the route form coastal area to Dome Fuji station in Antarctica were analyzed. The snow samples were collected along ca. 1000 km traverse route from Mikaeridai (S16; 69°01'S, 40°03'E, 590 m) to Dome Fuji station (77°19'S, 39°42'E, 3810 m) by the Japan Antarctica research expedition. The snow samples were also collected from a pit dug at Dome Fuji station. Those samples were collected in the 2009/2010 austral summer. The samples were transported to Japan without thawing. Quantitative analyses of sulfur species were performed using ion chromatograph and quadrupole type mass spectrometer. The isotopic ratios of isolated sulfur species were measured using elemental analyzer and the magnetic field type mass spectrometer. Average concentrations and maximum concentration of methanesulfonate ion in the snow samples were 17 ng/ml and 123 ng/ml, respectively. Average concentrations and maximum concentration of sulfate ion were ng/ml 63 and 419 ng/ml, respectively. Further results and discussion about the behavior and origin of sulfur species in the snow will be presented.

  2. Space Station

    NASA Technical Reports Server (NTRS)

    Anderton, D. A.

    1985-01-01

    The official start of a bold new space program, essential to maintain the United States' leadership in space was signaled by a Presidential directive to move aggressively again into space by proceeding with the development of a space station. Development concepts for a permanently manned space station are discussed. Reasons for establishing an inhabited space station are given. Cost estimates and timetables are also cited.

  3. Tectonic structure of East Antarctica

    NASA Astrophysics Data System (ADS)

    Leychenkov, German; Grikurov, Garrik; Golynsky, Alexander

    2013-04-01

    First overviews of tectonic structure of the Southern Continent were made by the pioneers of Antarctic earth science investigations almost 100 years ago. Despite rapidly advancing international geological studies under the Antarctic Treaty, the presentations of Antarctic tectonic structure remained largely speculative until the end of the past century when implementation of modern analytical and remote-sensing research technologies enabled compilation of more credible tectonic models of Antarctica. The East Antarctic bedrock consists mainly of the Precambrian crystalline complexes and the Paleozoic-Early Mesozoic platform units. Crystalline Shield is locally complicated by Neoproterozoic aulacogenes and Late Paleozoic to Mesozoic rifts. Shield assemblages reliably recognized in coastal outcrops indicate the predominant occurrence of Archean cratonic nuclei and Mesoproterozoic mobile belts. The undisturbed platform cover strata are exposed in East Antarctica mainly along its boundary with West Antarctica. Tectonic structure of ice-covered regions (more that 99% of the East Antarctic territory) is interpreted using mostly magnetic and bedrock topography data, but other geophysical and geological information (satellite, airborne and over-ice gravity; seismology; active seismics; erratics; detrital zircons dates; etc.) is also important. Archean cratons are geologically documented in western Dronning Maud Land, Enderby Land, Princess Elizabeth Land and in the southern Prince Charles Mts. Their distribution under the ice is marked by a specific magnetic pattern including low-amplitude mosaic and/or high-amplitude long-wavelength anomalies. The most extensive ancient craton being 1000 km across is believed to extend from the southern Prince Charles Mts. to the Gamburtsev Mts. Mesoproterozoic mobile belts are distinguished by elongated high-amplitude magnetic anomalies and are mapped along the costal area as the zone of 250-600 km wide. The Gamburtsev Mts. area is also interpreted to be a part of Mesoproterozoic mobile belt. Precambrian aulacogens and Paleozoic to Mesozoic rifts are more difficult to recognize with confidence from geophysical data, except the largest Lambert-Amery rift which is well expressed in potential fields and bedrock topography. Many other linear bedrock depressions are believed to result from ice erosion which probably amplified structural features such as faults, sutures, boundaries of tectonic provinces. Extensive platform cover is assumed to occur mainly in vast subglacial lowlands of East Antarctic interior. Geophysical data, as well as erratics found in costal moraines and offshore sediments, suggest that Beacon and/or Ferrar Supergroups or their stratigraphic/structural equivalents can be expected to continue under the ice beyond the limits of the Ross Orogen where they may rest on the older platform complexes and/or directly on the crystalline basement.

  4. Weddell Seal Research at Erebus Bay, Antarctica

    USGS Multimedia Gallery

    Technician recording seals' tag information in field notebook and portable computer.  Cold! Photo by USGS scientist William A Link at Erebus Bay, Antarctica.  Images were obtained under NMFS Permit No: 1032-1917.  ...

  5. THE BIRDS OF SEYMOUR ISLAND, ANTARCTICA

    Microsoft Academic Search

    Diego Montalti; Guillermo E. Soave

    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

  6. Geohydrology and distribution of volatile organic compounds in ground water in the Casey Village area, Bucks County, Pennsylvania

    USGS Publications Warehouse

    Sloto, Ronald A.; Conger, Randall W.; Grazul, Kevin E.

    1998-01-01

    Casey Village and the adjoining part of the U.S. Naval Air Warfare Center (NAWC) are underlain by the Late Triassic-age Stockton Formation, which consists of a dipping series of siltstones and sandstones. The direction of vertical ground-water gradients in the Stockton Formation varies among well locations and sometimes with time. Vertical gradients can be substantial; the difference in water levels at one well pair (two wells screened at different depths) was 7.1 ft (feet) over a 32-ft vertical section of the aquifer. Potentiometric-surface maps show a groundwater divide that bisects the Casey Village area. For wells screened between 18 and 64 ft below land surface (bls), the general ground-water gradient is to the east and northeast on the east side of the divide and to the south and southwest on the west side of the divide. For wells screened between 48 and 106 ft bls, the general ground-water gradient is to the northeast on the east side of the divide and to the southwest and northwest on the west side of the divide. An aquifer test at one well in Casey Village caused drawdown in wells on the opposite side of the ground-water divide on the NAWC and shifted the ground-water divide in the deeper potentiometric surface to the west. Drawdowns formed an elliptical pattern, which indicates anisotropy; however, anisotropy is not aligned with strike or dip. Hydraulic stress caused by pumping crosses stratigraphic boundaries. Between 1993 and 1996, the trichloroethylene (TCE) concentration in water samples collected from wells in Casey Village decreased. The highest concentration of TCE measured in water from one well decreased from 1,200 mg/L (micrograms per liter) in 1993 when domestic wells were pumped in Casey Village to 140 mg/L in 1996, 3 years after the installation of public water and the cessation of domestic pumping. This suggests that pumping of domestic wells may have contributed to TCE migration. Between 1993 and 1996, the tetrachloroethylene (PCE) concentration in water samples collected from wells in Casey Village decreased only slightly. The highest concentration of PCE measured in water from one well decreased from 720 mg/L in 1993 to 630 mg/L in 1996. The distribution of TCE and PCE in ground water indicates the presence of separate PCE and TCE plumes, each with a different source area. The TCE plume appears to be moving in two directions away from the ground-water divide area. The pumping of a domestic well may have caused TCE migration into the ground-water divide area. From the divide area, the TCE plume appears to be moving both to the east and the west under the natural hydraulic gradient. Aquifer-isolation tests conducted in the well with the highest TCE concentrations showed that concentrations of TCE in water samples from the isolated intervals were similar but slightly lower in the deeper isolated zones than in the shallower isolated zones. Upward flow was measured in this well during geophysical logging. If the source of TCE to the well was from shallow fractures, upward flow of less contaminated water could be flushing TCE from the immediate vicinity of this well. This may help explain why the concentration of TCE in water from this well decreased an order of magnitude between 1993 and 1996.

  7. Altitude and configuration of the potentiometric surface, Casey Village, Warminster and Upper Southampton townships, Bucks County, Pennsylvania, August 3, 1995

    USGS Publications Warehouse

    Sloto, Ronald A.; Grazul, Kevin E.

    1995-01-01

    A map showing the potentiometric surface in Casey Village, Warminster and Upper Southampton Townships, Bucks County, was constructed from water levels measured on August 3, 1995. The potentiometric surface, measured in 17 wells screened between 18 and 64 feet below land surface, ranged from 321.99 to 344.80 feet above sea level. The potentiometric surface, measured in 12 wells screened between 48 and 108 feet below land surface, ranged from 321.95 to 337.50 feet above sea level.

  8. Scharffenbergbotnen (Dronning Maud Land, Antarctica) blue-ice area dynamics

    E-print Network

    Moore, John

    Scharffenbergbotnen (Dronning Maud Land, Antarctica) blue-ice area dynamics Anna Sinisalo,1,2 Aslak, Dronning Maud Land, Antarctica, complement earlier, relatively sparse data on the ice-flow dynamics

  9. Reasons for medical consultation among members of the Indian Scientific Expeditions to Antarctica.

    PubMed

    Bhatia, Abhijeet; Malhotra, Pradip; Agarwal, Ashok Kumar

    2013-01-01

    The article attempts to analyze the disease burden in a healthy, pre-screened population subjected to prolonged residence in the hostile environment of Antarctica. This retrospective epidemiological study was conducted utilizing data from medical consultation room on board the Indian Antarctic expedition vessels and at Indian Antarctic station, Maitri from seven Indian Scientific Expeditions to Antarctica (ISEA). The study group (n=327) consisted of 325 men and two women. The total number of medical room consultations was 1989. Maximum consultations were for injuries (27.25%); 14.68% were musculoskeletal and 10.31% were bruises and lacerations. Disturbances of gastrointestinal tract (19.66%) were the second most common disorders. Psychological disturbances accounted for 2.66% consultations. Cold injuries constituted 2.01% consultations and photophthalmia accounted for 1.06% consultations. PMID:23423959

  10. Changing cold acclimatization patterns of men living in Antarctica

    Microsoft Academic Search

    A. S. Bodey

    1978-01-01

    Responses to a standard cold stress of 10°C for 2 h applied before (Melbourne) and four times during a year in Antarctica were observed in 10 adult male Caucasians, 7 of whom were re-tested after returning from Antarctica. An early form of cold acclimatization developed within a month of arriving in Antarctica in which the cold stress response was characterised

  11. TROPOSPHERIC CLOUDS IN ANTARCTICA David H. Bromwich,1,2

    E-print Network

    Howat, Ian M.

    TROPOSPHERIC CLOUDS IN ANTARCTICA David H. Bromwich,1,2 Julien P. Nicolas,1,2 Keith M. Hines,1 regions, little is known about clouds in Antarctica. This arises in part from the challenging deployment, and aerosol concentrations found in Antarctica create unique conditions for cloud for- mation that greatly

  12. Belgische wetenschappers ontdekken 18 kilo zware meteoriet op Antarctica

    E-print Network

    Claeys, Philippe

    Belgische wetenschappers ontdekken 18 kilo zware meteoriet op Antarctica donderdag 28 februari 2013 Antarctica', zegt ULB-geoloog en teamleider Vincent Debaille. `Dit is de grootste meteoriet die in 25 jaar gevonden is in oostelijk Antarctica.' De chondriet is momenteel in Japan voor onderzoek, waar hij aan een

  13. HYDROLOGIC PROCESSES INFLUENCING STREAMFLOW VARIATION IN FRYXELL BASIN, ANTARCTICA

    E-print Network

    MacDonald, Lee

    HYDROLOGIC PROCESSES INFLUENCING STREAMFLOW VARIATION IN FRYXELL BASIN, ANTARCTICA Peter of southern Victoria Land, Antarctica is a large polar desert located along the west coast of the Ross Sea Union 93 #12;ECOSYSTEM DYNAMICS IN A POLAR DESERT: THE MCMURDO DRY VALLEYS, ANTARCTICA94 alluvium

  14. INTRODUCTION The Antarctic midge, Belgica antarctica Jacobs 1900, is the

    E-print Network

    Lee Jr., Richard E.

    806 INTRODUCTION The Antarctic midge, Belgica antarctica Jacobs 1900, is the southernmost insect in early summer, mate, oviposit and die within 10days. B. antarctica is apterous, a common adaption in wind Peninsula. Not surprisingly, given its habitat, larvae of B. antarctica are extremely tolerant of a number

  15. Post Graduate Research Opportunities Aquatic Ecosystem Research at Gateway Antarctica

    E-print Network

    Hickman, Mark

    Post Graduate Research Opportunities Aquatic Ecosystem Research at Gateway Antarctica In existence moved to Gateway Antarctica at the University of Canterbury. The programme comes with a legacy of multidisciplinary research into all types of aquatic ecosystems in Antarctica, a network of international

  16. A BARREL of fun in AntARcticA

    E-print Network

    Christian, Eric

    A BARREL of fun in AntARcticA National Aeronautics and Space Administration www.nasa.gov Volume 10 balloon scientists, are having a BARREL of fun in Antarctica. The Balloon Array for Radiation belt--to launch over Antarctica. The balloon-borne instruments will gather data on magnetic systems and send

  17. Gateway Antarctica's Ministry of Foreign Affairs and Trade Scholarship

    E-print Network

    Hickman, Mark

    Gateway Antarctica's Ministry of Foreign Affairs and Trade Scholarship in Antarctic and Southern in support of research and teaching in Antarctic Studies in recognition of Antarctica as a continent devoted to the understanding of Antarctica or the Southern Ocean. At least one of the scholar's supervisors of studies

  18. Symposium-in-Print: Ultraviolet Radiation and Terrestrial Ecosystems The Influence of Ultraviolet-B Radiation on Growth, Hydroxycinnamic Acids and Flavonoids of Deschampsia antarctica during Springtime Ozone Depletion in Antarctica{y

    Microsoft Academic Search

    Christopher T. Ruhland; Fusheng S. Xiong; W. Dennis Clark; Thomas A. Day

    We examined the influence of solar ultraviolet-B radiation (UV-B; 280-320 nm) on the growth, biomass production and phenylpropanoid concentrations of Deschampsia antarctica during the springtime ozone depletion season at Palmer Station, along the Antarctic Peninsula. Treatments involved placing filters on frames over potted plants that reduced levels of biologically effective UV-B either by 83% (reduced UV-B) or by 12% (near-ambient

  19. Space analogue studies in Antarctica

    NASA Astrophysics Data System (ADS)

    Lugg, D.; Shepanek, M.

    1999-09-01

    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.

  20. Space analogue studies in Antarctica

    NASA Technical Reports Server (NTRS)

    Lugg, D.; Shepanek, M.

    1999-01-01

    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 mitogen 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.

  1. Gongguan Metro Station NTU Hospital Metro Station

    E-print Network

    Hung, Shih-Hao

    Gongguan Metro Station NTU Hospital Metro Station 3 2 1 2 3 4 SE61 SE1 S71 SE63 SE74 SE73 SE72 SE Railway Station Taipei Railway Station To Shandao Temple Metro Station To Daan Park Sec. 3, Jianguo S. Rd. To Jianguo Expressway Sec. 2, Fuxing S. Rd. To Technology Building Metro Station

  2. Crustal_@Structure Derived From Refractions and Wide-Angle Reflections in The Mizuho Plateau, East Antarctica

    Microsoft Academic Search

    K. Yoshii; K. Ito; M. Kanao

    2003-01-01

    In 1999-2000, the 41st Japanese Antarctic Research Expedition (JARE41) conducted high density seismic experiments from the coast and inland on the Mizuho Plateau, East Antarctica, along a 180km line with station spacings of 1km. In the record sections, we can pick direct waves through the ice sheets along with refracted and reflected waves from the crust and the Moho boundaries.

  3. Anthropogenic impacts on marine ecosystems in Antarctica.

    PubMed

    Aronson, Richard B; Thatje, Sven; McClintock, James B; Hughes, Kevin A

    2011-03-01

    Antarctica is the most isolated continent on Earth, but it has not escaped the negative impacts of human activity. The unique marine ecosystems of Antarctica and their endemic faunas are affected on local and regional scales by overharvesting, pollution, and the introduction of alien species. Global climate change is also having deleterious impacts: rising sea temperatures and ocean acidification already threaten benthic and pelagic food webs. The Antarctic Treaty System can address local- to regional-scale impacts, but it does not have purview over the global problems that impinge on Antarctica, such as emissions of greenhouse gases. Failure to address human impacts simultaneously at all scales will lead to the degradation of Antarctic marine ecosystems and the homogenization of their composition, structure, and processes with marine ecosystems elsewhere. PMID:21449967

  4. Initiation of Irrigation Effects on Temporal Nitrate Leaching F. X. M. Casey,* N. Derby, R. E. Knighton, D. D. Steele, and E. C. Stegman

    E-print Network

    Steele, Dean D.

    Initiation of Irrigation Effects on Temporal Nitrate Leaching F. X. M. Casey,* N. Derby, R. E that was converted from dryland to center- 1980). Albus and Knighton (1998) found that the initia- pivot irrigation in 1989. The vadose zone was monitored with four tion of irrigation caused a flush of NO3­N to the shallow

  5. Semantic Awareness in Product Lifecycle Management Systems Casey James Baker, Douglas Eddy, Dr. Sundar Krishnamurty, Dr. Ian Grosse, Dr. Jack Wileden

    E-print Network

    Mountziaris, T. J.

    enterprises turn to Product Lifecycle Management (PLM) systems to organize product development and to reduceSemantic Awareness in Product Lifecycle Management Systems Casey James Baker, Douglas Eddy, Dr time to market. Semantic awareness has the potential to enrich PLM systems, yet semantic functionality

  6. Persistence, Partnership and Public Will: The Annie E. Casey Foundation's Investments in Kentucky School Reform. Principles for Effective Education Grantmaking. Case in Brief Number 2

    ERIC Educational Resources Information Center

    Grantmakers for Education, 2012

    2012-01-01

    "Persistence, Partnership and Public Will" explores the sustained role the Annie E. Casey Foundation played in Kentucky for more than a decade to help create an environment in which the state's ambitious and comprehensive effort to improve education for all of its students would have the time, resources and attention needed to prove its worth. The…

  7. Persistence, Partnership and Public Will: The Annie E. Casey Foundation's Investments in Kentucky School Reform. Principles for Effective Education Grantmaking. Case Study Number 2

    ERIC Educational Resources Information Center

    Sherwood, Kay E.

    2006-01-01

    This case study explores the sustained role the Annie E. Casey Foundation played for more than a decade to help create an environment in which an ambitious and comprehensive effort to improve public education for all children in Kentucky would have the time, resources and attention needed to prove its worth. As the case describes, the sweeping…

  8. Preparing Young People to Succeed in College and Beyond. The Connection Strategy: Stories and Results from the Annie E. Casey Foundation's Education Investments

    ERIC Educational Resources Information Center

    Jehl, Jeanne

    2007-01-01

    For many young people, the "pipeline" to educational and economic success is truly broken. This report describes how some of the Annie E. Casey Foundation's education grantees in Atlanta are working to mend the pipeline for young people in their communities by connecting standards and expectations for learning from early childhood to college entry…

  9. Ties That Bind: The Practice of Social Networks. Number Two in a Series of Reports on Social Networks from The Annie E. Casey Foundation

    ERIC Educational Resources Information Center

    Bailey, Terri J.

    2006-01-01

    This report documents the Annie E. Casey Foundation's effort to learn from families, communities and organizations around the country about their experiences with social network strategies and approaches. Using the voices and experiences of the families and organizations visited, the report summarizes findings from these visits and helps lay the…

  10. Sensible and latent heat flux estimates in Antarctica

    NASA Technical Reports Server (NTRS)

    Stearns, Charles R.; Weidner, George A.

    1993-01-01

    The assumption has been made that the net annual contribution of water by the processes of deposition and sublimation to the Antarctic Ice Sheet is zero. The U.S. Antarctic Program started installing reliable automatic weather stations on the Antarctic Continent in 1980. The initial units were equipped to measure wind speed, wind direction, air pressure, and air temperature. During the 1983-1984 field season in Antarctica, three units were installed that measured a vertical air temperature difference between the nominal heights of 0.5 m and 3.0 m and relative humidity at a nominal height of 3 m. The measurements of the vertical air temperature difference and the relative humidity are the minimum required to estimate the sensible and latent heat fluxes to the air, while not exceeding the available energy requirements for the weather stations. The estimates of the net annual sublimation and deposition on the Ross Ice Shelf amount to 20 to 80 percent of the annual accumulation. We conclude that the assumption that annual sublimation and deposition are zero is not valid under Antarctic conditions.

  11. Live from Antarctica: Then and Now

    NASA Technical Reports Server (NTRS)

    1994-01-01

    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.

  12. The BESS-Polar II Long Duration Flight above Antarctica

    NASA Astrophysics Data System (ADS)

    Sasaki, Makoto

    The Balloon-borne Experiment with a Superconducting Spectrometer, BESS, has been developed to study elementary particle phenomena in the early universe through measurements of low energy antiprotons to investigate their origin and through a search for antihelium. The BESS collaboration carried out nine northern latitude flights between 1993 and 2002. BESS- Polar is an advanced program of the BESS collaboration to study these topics with much greater precision using long duration flights above Antarctica. The BESS-Polar spectrometer was successfully developed to accumulate much larger numbers of events during long duration flights around the South Pole. Approximately a factor of four reductions in the amount of material in the particle beam enables measurement of much lower energy antiprotons down to 100 MeV (at top of atmosphere). The first BESS-Polar flight (BESS-Polar I) of 8.5 days was carried out above Antarctica in December 2004, recording 900 million cosmic-ray events. The second BESS-Polar flight (BESS-Polar II) was successfully carried out in the austral summer season of 2007-2008. Based on experience with BESS-Polar I, the spectrometer was improved in performance and achieved long term stability during the flight. A newly constructed magnet with a larger liquid He capacity and improved thermal insulation and an upgraded data storage system with larger capacity of hard disk drives (HDDs) enabled longer observation time. BESS-Polar II was launched on December 22, 2007 from Williams Field, McMurdo Station, in Antarctica. The spectrometer worked properly and observed cosmic rays for about 24.5 days at float altitude, recording 4.6 billion events on the HDDs until the limit of the magnet operation was reached on January 16, 2008. The flight was terminated and the spectrometer was safely landed on the West Antarctic ice sheet ( 1000 km from the South Pole) on January 21, 2008. Here, the BESS-Polar instrument is discussed, highlighting improvements made for BESS-Polar II, and overviews of the flight and performance are reported.

  13. Ecological and physiological investigations in continental Antarctic cryptogams

    Microsoft Academic Search

    L. Kappen; M. Breuer; M. Bölter

    1991-01-01

    Microclimate and CO2 exchange of the lichen Usnea sphacelata were measured during summen on a hill near Casey Station, Bailey Peninsula, Wilkes Land, Antarctica. Within a period of 52 days (November 10 until December 31, 1985), 8 diurnal courses of net photosynthesis were measured in naturally snow-covered lichen thalli, and 9 diurnal courses in thalli experimentally sprayed with melt water.

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

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

    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.

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

    NASA Astrophysics Data System (ADS)

    Vazquez Becerra, Guadalupe Esteban

    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 Reference Frame (ITRF), the McMurdo (MCM4) IGS (The International GNSS Service for Geodynamics, formerly the International GPS Service) site was adopted as part of the TAMDEF network. The following scientific achievements obtained from the cited analysis will be discussed as follows: (1) The GPS data processing for the TAMDEF network relied on the PAGES (Program for Adjustment of GPS Ephemerides) software that uses the double-differenced iono-free linear combination, which helps removing a big partial of bias (mm level) in the final positioning. (2) To validate the use of different antenna types in TAMDEF, an antenna testing experiment was conducted using the National Geodetic Survey (NGS) antenna calibration data, appropriate for each antenna type. Sub-daily and daily results from the antenna testing are at the sub-millimeter level, based on the fact that 24-hour solutions were used to average any possible bias. (3) A potential contributor that might have an impact on the TAMDEF stations positioning is the pseudorange multipath effect; thus, the root mean squared variations were estimated and analyzed in order to identify the most and least affected sites. MCM4 was found to be the site with highest multipath, and this is not good at all, since MCM4 is the primary ITRF access point for this part of Antarctica. Additionally, results from the pseudorange multipath can be used for further data cleaning to improve positioning results. (4) The Ocean Tide Modeling relied on the use of two models: CATS02.01 (Circum Antarctic Tidal Simulation) and TPXO6.2 (TOPEX/Poseidon) to investigate which model suits the Antarctic conditions best and its effect on the vertical coordinate component at the TAMDEF sites. (5) The scatter for the time-series results of the coordinate components for the TAMDEF sites are smaller when processed with respect to the Antarctic tectonic plate (Case I), in comparison with the other tectonic plates outside Antarctica (Case II-IV). Also, the seasonal effect due to the time-series seen in the TAMDEF sites with longer data span are site dependent; thus, data processing is not the reason for these effects. (6) Furthermore, the results coming from a homogeneous global network with coordinates referred and transformed to the ITRF2000 at epoch 2005.5 reflect the quality of the solution, obtained when processing TAMDEF network data with respect to the Antarctic tectonic plate. (7) An optimal data reduction strategy was developed, based on three different troposphere models and mapping functions, tested and used to estimate the total wet zenith delay (TWZD) which later was transformed to precipitable water vapor (PWV). PWV was estimated from GPS measurements and validated with a numerical weather model, AMPS (Antarctic Mesoscale Prediction System) and radiosonde PWV. Additionally, to validate the TWZD estimates at the MCM4 site before their conversion into the GPS PWV, these estimates were directly compared to TWZD computed by the CDDIS (Crustal Dynamics Data Information System) analysis center. (8) The results from the Least-Squares adjustment with Stochastic Constraints (SCLESS) as performed with PAGES are very comparable (mm-level) to those obtained from the alternative adjustment approaches: MINOLESS (Minimum-Norm Least-Squares adjustment); Partial-MINOLESS (Partial Minimum-Norm Least-Squares adjustment), and BLIMPBE (Best Linear Minimum Partial-Bias Estimation). Based on the applied network adjustment models within the Antarctic tectonic plate (Case I), it can be demonstrated that the GPS data used are clean of bias after proper care has been taken of ionosphere, troposphere, multipath, and some other s

  16. Summer biomass of a population of Phyllophora antarctica (Phyllophoraceae, Rhodophyta) from Antarctica

    Microsoft Academic Search

    Mario Cormaci; Giovanni Furnari; Blasco Scammacca; Giuseppina Alongi; Marcello Catra

    1997-01-01

    Results of a study on summer biomass in aninfralittoral population of Phyllophora antarctica A.et E. S. Gepp from Terra Nova\\u000a Bay (Ross Sea,Antarctica) are reported. The population studied grewat depths of 5 to 12 m. The highest value of biomass(1548\\u000a wet g m?2) was found at the end of January at6 m depth. Data showed that biomass depended mainly onthe

  17. Station Identifier

    Microsoft Academic Search

    J. Stepan

    1968-01-01

    This paper describes an end office tributary identifier which sends to a toll center the calling subscriber's directory number. It is arranged to interface with the Bell System's centralized automatic message accounting (CAMA) centers. The electronic identifier operates on either a terminal per line, a terminal per station, or mixed basis. In operating, it feeds an ac signal on the

  18. 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.

  19. Medical memorials in Antarctica: a gazetteer of medical place-names.

    PubMed

    Sullivan, Peter; Pearn, John

    2012-11-01

    In Antarctica an astonishing more than 300 'medical' place-names record the lives of surgeons and physicians who have served as leaders, clinicians and scientists in the field of polar medicine and other doctors memorialized for their service to medicine. These enduring medical memorials are to be found in the names of glaciers, mountains, capes and islands of the vast frozen Southern Continent. This Antarctic Medical Gazetteer features, inter alii, doctor-expedition leaders, including Jean-Baptiste Charcot (1867-1936) of France and Desmond Lugg (b. 1938) of Australia. The Medical Gazetteer lists 43 geographical features on Brabant Island that were named after famous doctors. This Gazetteer also includes a collection of medical place-names on the Loubet Coast honouring Dr John Cardell (1896-1966) and nine other pioneers who worked on the prevention of snow blindness and four islands of the Lyall Islands Group, including Surgeon Island, named after United States Antarctic Medical Officers. Eleven geographic features (mountains, islands, nunataks, lakes and more) are named after Australian doctors who have served with the Australian National Antarctic Research Expeditions based at Davis Station. Biographic memorials in Antarctica comprise a collective witness of esteem, honouring in particular those doctors who have served in Antarctica where death and injury remains a constant threat. PMID:23143322

  20. Receiver functions from west Antarctica; crust and mantle properties from POLENET

    NASA Astrophysics Data System (ADS)

    Aster, R. C.; Chaput, J. A.; Hansen, S. E.; Nyblade, A.; Wiens, D. A.; Huerta, A. D.; Wilson, T. J.; Anandakrishnan, S.

    2011-12-01

    We use receiver functions to extract crustal thickness and mantle transition zone depths across a wide extent of West Antarctica and the Transantarctic mountains using POLENET data, including recently recovered data from a 14-station West Antarctic Rift Zone transect. An adaptive approach for generating and analyzing P-receiver functions over ice sheets and sedimentary basins (similar to Winberry and Anandakrishnan, 2004) is applied using an extended time multitaper deconvolution algorithm and forward modeling synthetic seismogram fitting. We model P-S receiver functions via a layer stripping methodology (beginning with the ice sheet, if present), and fit increasingly longer sections of synthetic receiver functions to model the multiples observed in the data derived receiver functions. We additionally calculate S-P receiver functions, which provide complementary structural constraints, to generate consistent common conversion point stacks to image crustal and upper mantle discontinuities under West Antarctica. Crust throughout West Antarctica is generally thin (23-29 km; comparable to the U.S. Basin and Range) with relative thickening under the Marie Byrd Land volcanic province (to 32 km) and the Transantarctic Mountains. All constrained west Antarctic crust is substantially thicker than that in the vicinity of Ross Island, where crust as thin as 17 km is inferred in the Terror Rift region.

  1. Terrestrial ecosystem processes of Victoria Land, Antarctica

    Microsoft Academic Search

    J. E. Barrett; R. A. Virginia; D. W. Hopkins; J. Aislabie; R. Bargagli; J. G. Bockheim; I. B. Campbell; W. B. Lyons; D. L. Moorhead; J. N. Nkem; R. S. Sletten; H. Steltzer; D. H. Wall; M. D. Wallenstein

    2006-01-01

    Terrestrial environments of Victoria Land, Antarctica are ideal systems to test hypotheses about the sensitivity of ecosystem processes to climate variability, and the relationships between soil biodiversity and ecosystem functioning because of their high sensitivity to climate change and their limited diversity. This region is also considered among the most pristine of ecosystems, and therefore may serve as an indicator

  2. Atmospheric transmission and noise measurements in Antarctica

    Microsoft Academic Search

    G. dall'Oglio; P. de Bernardis; S. Masi; A. Moleti; B. Melchiorri; W PECORELLA; L PIZZO

    1988-01-01

    The authors describe a set of measurements carried out in Antarctica during the second Italian Antarctic Expedition. Atmospheric precipitable water vapour, millimetric transmission and noise were monitored for 2 months during the austral summer. The results suggest that the site is favourable for far infrared astronomy measurements.

  3. Read--and Walk--to Antarctica

    ERIC Educational Resources Information Center

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

    2012-01-01

    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…

  4. Humus in some soils from Western Antarctica

    Microsoft Academic Search

    E. Abakumov

    2009-01-01

    Soils of Antarctica are well known as a thick profile soils with low amounts of humus concentrated in the upper layers - O or A horizons. Also there are specific soils of seashore landscapes which affected by penguins guano accumulation and, therefore characterized by high stocks of organic matter in solum. These two types of soils were studied during the

  5. Language Learning Stations.

    ERIC Educational Resources Information Center

    Strauber, Sandra K.

    1981-01-01

    Describes use of learning stations at elementary and secondary levels. Explains vocabulary, grammar, conversation, listening, reading and culture stations; materials and equipment for stations; management concerns. (BK)

  6. ESTIMATION OF SNOW ACCUMULATION IN ANTARCTICA USING AUTOMATED ACOUSTIC DEPTH GAUGE MEASUREMENTS

    E-print Network

    Wisconsin at Madison, University of

    ESTIMATION OF SNOW ACCUMULATION IN ANTARCTICA USING AUTOMATED ACOUSTIC DEPTH GAUGE MEASUREMENTS: ____________________________ DATE: _______________________ Dr. Gregory J. Tripoli, Academic Advisor #12;Abstract Antarctica microwave sounders, snow gauges, or radar are not feasible or not available in Antarctica at the present

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

    Microsoft Academic Search

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

    2009-01-01

    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.

  8. Data on bottom water in Prydz Bay, Antarctica, revised

    NASA Astrophysics Data System (ADS)

    Bindoff, Nathaniel L.; Forbes, Andrew; Wong, Annie P. S.

    We report on salinity biases in conductivity-temperature-depth (CTD) data collected offshore Prydz Bay that affect conclusions about possible bottom water formation. The role of the Prydz Bay region (68-81°E) in bottom water production around Antarctica is an important unresolved issue [Smith and Treguer, 1994; Nunes Vaz and Lennon, 1996; Whitworth et al., 1998]. Wong, Bindoff, and Forbes [1998] identified a new, dense water type over the abyssal plain northwest of the Prydz Bay Channel at ˜72.5°E. Its spatial pattern was such that the highest sea floor salinities, ˜0.03 psu above historical measurements, were observed nearest the channel and decreased westward, away from Prydz BayExamination of the calibrated CTD data bottle data analyzed in Wong et al. [1998] shows a systematic bias in salinities off the continental shelf, most strongly in the stations to the west of Prydz Bay. The bias appears directly attributable to an undetected deterioration in conductivity cell performance toward the end of the observation program. The change in cell behavior is consistent with a cracked conductivity cell. This deterioration introduced an artificial curvature into the salinity profiles at depths exceeding 2000 m and a wider spread of the bottom salinity values to the west and north of Prydz Bay.

  9. Ambient noise correlation on the Amery Ice Shelf, East Antarctica

    NASA Astrophysics Data System (ADS)

    Zhan, Zhongwen; Tsai, Victor C.; Jackson, Jennifer M.; Helmberger, Don

    2014-03-01

    The structure of ice shelves is important for modelling the dynamics of ice flux from the continents to the oceans. While other, more traditional techniques provide many constraints, passive imaging with seismic noise is a complementary tool for studying and monitoring ice shelves. As a proof of concept, here we study noise cross-correlations and autocorrelations on the Amery Ice Shelf, East Antarctica. We find that the noise field on the ice shelf is dominated by energy trapped in a low-velocity waveguide caused by the water layer below the ice. Within this interpretation, we explain spectral ratios of the noise cross-correlations as P-wave resonances in the water layer, and obtain an independent estimate of the water-column thickness, consistent with other measurements. For stations with noise dominated by elastic waves, noise autocorrelations also provide similar results. High-frequency noise correlations also require a 50-m firn layer near the surface with P-wave velocity as low as 1 km s-1. Our study may also provide insight for future planetary missions that involve seismic exploration of icy satellites such as Titan and Europa.

  10. Climatological observations and predicted sublimation rates at Lake Hoare, Antarctica.

    USGS Publications Warehouse

    Clow, G.D.; McKay, C.P.; Simmons, G.M., Jr.; Wharton, R.A., Jr.

    1988-01-01

    In December 1985, an automated meteorological station was established at Lake Hoare in the dry valley region of Antarctica. Here, we report on the first year-round observations available for any site in Taylor Valley. This dataset augments the year-round data obtained at Lake Vanda (Wright Valley) by winter-over crews during the late 1960s and early 1970s. The mean annual solar flux at Lake Hoare was 92 W m-2 during 1986, the mean air temperature -17.3 degrees C, and the mean 3-m wind speed 3.3 m s-1. The local climate is controlled by the wind regime during the 4-month sunless winter and by seasonal and diurnal variations in the incident solar flux during the remainder of the year. Temperature increases of 20 degrees-30 degrees C are frequently observed during the winter due to strong fo??hn winds descending from the Polar Plateau. A model incorporating nonsteady molecular diffusion into Kolmogorov-scale eddies in the interfacial layer and similarity-theory flux-profiles in the surface sublayer, is used to determine the rate of ice sublimation from the acquired meteorological data. Despite the frequent occurrence of strong winter fo??hns, the bulk of the annual ablation occurs during the summer due to elevated temperatures and persistent moderate winds. The annual ablation from Lake Hoare is estimated to have been 35.0 +/- 6.3 cm for 1986.

  11. Thermalizing a telescope in Antarctica: Analysis of ASTEP observations

    E-print Network

    Guillot, Tristan; Agabi, Abdelkrim; Rivet, Jean-Pierre; Daban, Jean-Baptiste; Mekarnia, Djamel; Aristidi, Eric; Schmider, Francois-Xavier; Crouzet, Nicolas; Gonçalves, Ivan; Gouvret, Carole; Ottogalli, Sébastien; Faradji, Hélène; Blanc, Pierre-Eric; Bondoux, Eric; Valbousquet, Franck

    2015-01-01

    The installation and operation of a telescope in Antarctica represent particular challenges, in particular the requirement to operate at extremely cold temperatures, to cope with rapid temperature fluctuations and to prevent frosting. Heating of electronic subsystems is a necessity, but solutions must be found to avoid the turbulence induced by temperature fluctua- tions on the optical paths. ASTEP 400 is a 40 cm Newton telescope installed at the Concordia station, Dome C since 2010 for photometric observations of fields of stars and their exoplanets. While the telescope is designed to spread star light on several pixels to maximize photometric stability, we show that it is nonetheless sensitive to the extreme variations of the seeing at the ground level (between about 0.1 and 5 arcsec) and to temperature fluctuations between --30 degrees C and --80 degrees C. We analyze both day-time and night-time observations and obtain the magnitude of the seeing caused by the mirrors, dome and camera. The most important ...

  12. Meteorological data for the astronomical site at Dome A, Antarctica

    E-print Network

    Hu, Yi; Ashley, Michael C B; Bonner, Collin S; Hu, Keliang; Liu, Qiang; Li, Yuansheng; Ma, Bin; Wang, Lifan; Wen, Haikun

    2014-01-01

    We present an analysis of the meteorological data collected at Dome A, Antarctica by the Kunlun Automated Weather Station, including temperatures and wind speeds at eight elevations above the snow surface between 0m and 14.5m. The average temperatures at 2m and 14.5m are $-54^{\\circ}$C and $-46^{\\circ}$C, respectively. We find that a strong temperature inversion existed at all heights for more than 70% of the time, and the temperature inversion typically lasts longer than 25 hours, indicating an extremely stable atmosphere. The temperature gradient is larger at lower elevations than higher elevations. The average wind speed was 1.5m/s at 4m elevation. We find that the temperature inversion is stronger when the wind speed is lower and the temperature gradient decreases sharply at a specific wind speed for each elevation. The strong temperature inversion and low wind speed results in a shallow and stable boundary layer with weak atmospheric turbulence above it, suggesting that Dome A should be an excellent site...

  13. Site testing for submillimetre astronomy at Dome C, Antarctica

    E-print Network

    Tremblin, P; 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

    2011-01-01

    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 um 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 environ- ment. Dome C offers exceptional conditions in terms of absolute atmospheric transmission and stability for submillimetre astron- omy. 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 um is achieved for 75% of the time. The 200-um window opens with a typical transmission...

  14. Analysis of continuous GPS measurements from southern Victoria Land, Antarctica

    USGS Publications Warehouse

    Willis, Michael J.

    2007-01-01

    Several years of continuous data have been collected at remote bedrock Global Positioning System (GPS) sites in southern Victoria Land, Antarctica. Annual to sub-annual variations are observed in the position time-series. An atmospheric pressure loading (APL) effect is calculated from pressure field anomalies supplied by the European Centre for Medium-Range Weather Forecasts (ECMWF) model loading an elastic Earth model. The predicted APL signal has a moderate correlation with the vertical position time-series at McMurdo, Ross Island (International Global Navigation Satellite System Service (IGS) station MCM4), produced using a global solution. In contrast, a local solution in which MCM4 is the fiducial site generates a vertical time series for a remote site in Victoria Land (Cape Roberts, ROB4) which exhibits a low, inverse correlation with the predicted atmospheric pressure loading signal. If, in the future, known and well modeled geophysical loads can be separated from the time-series, then local hydrological loading, of interest for glaciological and climate applications, can potentially be extracted from the GPS time-series.

  15. Tohoku Tsunami Created Icebergs In Antarctica

    NSDL National Science Digital Library

    Patrick Lynch

    This website, from NASA, offers an article, images, and a video about the connection between the 2011 tsunami off the coast of Japan and a large ice calving event in Antarctica. Scientists observed ice calving soon after the Japan event and attributed it to the swell caused by the tsunami; this finding marks the first direct observation of such a connection between tsunamis and icebergs.

  16. The Landsat Image Mosaic of Antarctica

    NASA Astrophysics Data System (ADS)

    Bindschadler, R.; Vornberger, P.; Fleming, A.; Fox, A.; Morin, P.

    2008-12-01

    The first-ever true-color, high-resolution digital mosaic of Antarctica has been produced from nearly 1100 Landsat-7 ETM+ images collected between 1999 and 2003. The Landsat Image Mosaic of Antarctica (LIMA) project was an early benchmark data set of the International Polar Year and represents a close and successful collaboration between NASA, USGS, the British Antarctic Survey and the National Science Foundation. The mosaic was successfully merged with lower resolution MODIS data south of Landsat coverage to produce a complete true-color data set of the entire continent. LIMA is being used as a platform for a variety of education and outreach activities. Central to this effort is the NASA website 'Faces of Antarctica' that offers the web visitor the opportunity to explore the data set and to learn how these data are used to support scientific research. Content is delivered through a set of mysteries designed to pique the user's interest and to motivate them to delve deeper into the website where there are various videos and scientific articles for downloading. Detailed lesson plans written by teachers are provided for classroom use and Java applets let the user track the motion of ice in sequential Landsat images. Web links take the user to other sites where they can roam over the imagery using standard pan and zoom functions, or search for any named feature in the Antarctic Geographic Names data base that returns to the user a centered true-color view of any named feature. LIMA also has appeared is a host of external presentations from museum exhibits, to postcards and large posters. It has attracted various value-added providers that increase LIMA's accessibility by allowing users to specify subsets of the very large data set for individual downloads. The ultimate goal of LIMA in the public and educational sector is to enable everyone to become more familiar with Antarctica.

  17. THE GENUS SARCOGYNE ( ACAROSPORACEAE ) IN ANTARCTICA

    Microsoft Academic Search

    R. D. SEPPELT; P. L. NIMIS; M. CASTELLO

    1998-01-01

    Sarcogyne angulosaC. W. Dodge & G. E. Baker, described as an endemic from continental Antarctic localities, is reduced to synonymy withS. privigna(Ach.) A. Massal., a species known from Europe, North America, North Africa and Saudi Arabia, and now Antarctica. The relationship to Polysporina simplex (Davies) V|$$|Ahezda is discussed. It is suggested that the nameSarcogyne griseaDodge, also described as an Antarctic

  18. Anthropogenic and natural disturbances to marine benthic communities in Antarctica

    SciTech Connect

    Lenihan, H.; Oliver, J.S. [Moss Landing Marine Labs., CA (United States)

    1995-05-01

    Sampling and field experiments were conducted from 1975 to 1990 to test how the structure of marine benthic communities around McMurdo Station, Antarctica varied with levels of anthropogenic contaminants in marine sediments. The structure of communities (e.g., infauna density, species composition, and life history characteristics) in contaminated and uncontaminated areas were compared with the structure of communities influenced by two large-scale natural disturbances, anchor ice formation and uplift or iceberg scour. Benthic communities changed radically along a steep spatial gradient of anthropogenic hydrocarbon, metal, and PCB contamination around McMurdo Station. The heavily contaminated end of the gradient, Winter Quarters Bay, was low in infaunal and epifaunal abundance and was dominated by a few opportunistic species of polychaete worms. The edge of the heavily contaminated bay, the transition area, contained several motile polychaete species with less opportunistic life histories. Uncontaminated sedimentary habitats harbored dense tube mats of infaunal animals numerically dominated by populations of polychaete worms, crustaceans, and a large suspension feeding bivalve. These species are generally large and relatively sessile, except for several crustacean species living among the tubes. Although the community patterns around anthropogenic and natural disturbances were similar, particularly motile and opportunistic species at heavily disturbed and marginal areas, the natural disturbances cover much greater areas of the sea floor about the entire Antarctic continent. On the other hand, recovery from chemical contamination is likely to take many more decades than recovery from natural disturbances as contaminant degradation is a slow process. 77 refs., 6 figs., 5 tabs.

  19. The Ice: A Journey to Antarctica

    NASA Astrophysics Data System (ADS)

    Ford, Arthur B.

    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.

  20. A Vibroseis Seismic Source for Climate, Ice Sheet and Tectonic Studies in Antarctica

    NASA Astrophysics Data System (ADS)

    Speece, M. A.; Luyendyk, B. P.; Powell, R. D.; Wilson, D. S.; Pekar, S. F.; Harwood, D. M.; Tulaczyk, S. M.

    2012-12-01

    Seismology's role in Antarctica is to help determine the geology of the subsurface of this still largely unexplored continent. Seismic reflection surveys in Antarctica have traditionally been collected as marine multichannel and single channel data. However, controlled or active source seismic experiments have played an integral, albeit limited, part in geophysical surveys of the Antarctic ice sheet. In more recent years, sea-ice and ice-shelf seismic reflection surveys have shown promise for producing useful data for regions not accessible by ship. Unfortunately a thick firn layer that covers much of the Antarctica ice sheet has limited the use of surface-based active seismic sources. To overcome attenuation caused by the firn layer, explosives are typically placed in 10 to 30 m-deep boreholes. These shot holes can be drilled by a variety of techniques but all require significant time and energy. In contrast to an impulsive seismic source that releases energy over about a millisecond duration, a seismic vibrator (vibroseis) emits energy as a controlled sweep of frequencies over several seconds. As a consequence, energy losses due to inelastic processes are less because of reduced ground pressure and the total energy produced is integrated over the length of the sweep. Long seismic reflection profiles across Antarctica could be accomplished efficiently by using a vibroseis that in turn pulls a snow streamer. We propose the acquisition of a vibroseis for Antarctic research by scientists within the U.S. Antarctic Program (USAP). Antarctic research objectives that could be impacted by the use of a seismic vibrator include (1) mapping of sub-ice stratigraphic sequences suitable for sampling by scientific drilling, (2) correlating offshore and onshore seismic data and complementing airborne geophysical surveys to help determine Antarctica's geologic history, (3) identifying ice-bedrock interface properties and exploring grounding-line processes, (4) exploring sub-glacial lakes and water-routing systems, and (5) investigating the seismic properties of ice sheets. Suggested seismic profiles include the South Pole traverse route across the Ross Ice Shelf with diversion routes to Coulman High and the Siple Coast. Additional profiles are planned for Byrd Station to West Antarctic Ice Sheet (WAIS) Divide camp and continuing to Pine Island Glacier, and over the 'Discovery Deep' trough, seaward of Byrd Glacier in the eastern Ross Embayment. Projects to consider for the long term include the boundary between West and East Antarctica that is expressed as the Transantarctic Mountains Front. Existing seismic data to define the structures at this boundary are limited. Basins in bedrock behind these mountains are proposed to be sediment free but no seismic reflection data exist to support that hypothesis. The recent detailed mapping of the bedrock of the Gamburtsev Mountains and the nearby Lambert Graben offer further targets for exploration of East Antarctica. An overland traverse has been established between South Pole and the AGAP South site where aerogeophysical surveys over these mountains were based, and this traverse route could be the starting point of a vibroseis research program in East Antarctica.

  1. The French-Italian Concordia Station

    NASA Astrophysics Data System (ADS)

    Mekarnia, Djamel; Frenot, Yves

    2013-01-01

    Concordia is a French-Italian permanent station located at Dome C, Antarctica. The station provides accommodation for up to 16 people over winter and more than 70 scientists and technicians during the austral summer. The scientific projects implemented at Concordia are strictly dependent on the characteristics of the site: a) the presence of a 3 300 m thick ice cap that allows access to the planet's climate archives and the reconstruction of glacial-interglacial cycles over more than 800 000 years; b) a particularly stable pure and dry atmosphere ideal for astronomy observations and for research on the chemical composition of the atmosphere; c) a distant location from coastal perturbations favourable to magnetic and seismological observatories to complement a poor world data network in the southern hemisphere; and d) a small totally isolated group of people confined to the station over a long winter, offering an opportunity for a range of medical and psychological studies useful to prepare long duration deep space missions. We will address the main characteristics of this station and its interest for science.

  2. Site testing Dome A, Antarctica

    NASA Astrophysics Data System (ADS)

    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.

    2006-06-01

    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.

  3. Lutzow-Holm Bay and the Shirase Glacier, Antarctica

    NASA Technical Reports Server (NTRS)

    2003-01-01

    These views from the Multi-angle Imaging SpectroRadiometer (MISR) portray the Lutzow-Holm Bay region of Queen Maud Land, East Antarctica, on September 5,2002. Although Queen Maud Land remains one of the least studied regions of Antarctica, Lutzow-Holm Bay is an exception. Syowa (pronounced 'Showa') Station is the Japanese Antarctic Research Expedition base situated on Ongul Island, just off the eastern coast of the Bay (in the top right-hand portion of these views). Scientists there have studied changes in the ice sheet and sea level for several decades. Large outlet glaciers, such as the fast-flowing Shirase Glacier in the lower right-hand corner of these images, are the primary drainage systems for the Antarctic ice sheet.

    These two views provide information on both the spectral and angular reflectance properties of the region and can be used to understand the geophysical environment. The top panel shows the region from MISR's downward-looking (nadir) camera and is a false-color view in which the near-infrared, green and blue spectral bands have been displayed as red, green and blue. Because of the tendency of water to absorb near-infrared wavelengths, some ice types exhibit an especially bright blue hue in this display.

    The lower panel is a multi-angular composite from three MISR cameras in which changes in reflection at different view angles, as well as in the near-infrared spectral region, assist with the identification of rough and smooth ice surfaces. In this display, red band data from MISR's 60-degree forward and backward-viewing cameras are displayed as red and blue, respectively, and near-infrared data from the nadir camera are displayed as green. Using this technique, surfaces that predominantly exhibit backward scattering (generally rough surfaces) appear red/orange, and surfaces that predominantly exhibit forward scattering (generally smooth surfaces) appear in blue hues. Clouds (and other surfaces that exhibit both forward and backward scattering) appear purple.

    The Multi-angle Imaging SpectroRadiometer observes the daylit Earth continuouslyand every 9 days views the entire globe between 82 degrees north and 82 degrees south latitude. These data products were generated from a portion of the imagery acquired during Terra orbit 16454. The panels cover an area of about 335 kilometers x 257 kilometers, and utilize data from blocks 145 to 147 within World Reference System-2 path 151.

  4. STRESS PROTEINS OF THE ANTARCTIC MIDGE, BELGICA ANTARCTICA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Antarctica presents one of the earth’s most inhospitable environments. Though an abundance of animals have adapted to life associated with the sea in this part of the world, few animals have adapted to the rigors of a terrestrial existence. One exception is the flightless midge Belgica antarctica ...

  5. PUTATIVE STRESS REGULATED GENES OF THE ANTARCTIC MIDGE, BELGICA ANTARCTICA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Antarctica presents one of the earth’s most inhospitable environments. Though an abundance of animals have adapted to life associated with the sea in this part of the world, few animals have adapted to the rigors of a terrestrial existence. One exception is the flightless midge Belgica antarctica ...

  6. Moisture source of precipitation in Western Dronning Maud Land, Antarctica

    Microsoft Academic Search

    C. H. Reijmer; M. R. Van Den Broeke

    2001-01-01

    Moisture sources for snow falling in Dronning Maud Land (DML), Antarctica, are calculated for 1998 using three dimensional 5-days backward air parcel trajectories. The drilling site of the European Project onIce CoringinAntarctica(EP1CA) inDMLischosenasthemainarrivalpoint (75.0°S, 0.01\\

  7. Meteorite collection and ice samples from the Pecora Escarpment, Antarctica

    Microsoft Academic Search

    Paul P. Sipiera; Birgit I. Sattler

    2004-01-01

    In January 2002 the Planetary Studies Foundation returned to Antarctica to conduct a systematic search for meteorites on the blue ice fields near the Pecora Escarpment. The Pecora Escarpment area was previously searched by two National Science Foundation (NSF) teams that collectively recovered 526 meteorites. The two primary goals of the PSF Antarctica 2002 expedition were to determine if a

  8. Charnockites from East Antarctica and their geological typification

    Microsoft Academic Search

    E. V. Mikhalsky; J. W. Sheraton; N. V. Vladykin

    2006-01-01

    Charnockitic rocks (orthopyroxene-bearing granitoids) are important and characteristic rocks exposed in East Antarctica (Fig. 1). The origin of these rocks and their tectonic setting has been a matter of hot debate since the pioneering studies in Antarctica. The emplacement of intrusive charnockites was interpreted as an indication of cratonization of the Early Precambrian Antarctic Shield or its subsequent tectonic activity

  9. Glacial/interglacial ice-stream stability in the Weddell1 Sea embayment, Antarctica2

    E-print Network

    1 Glacial/interglacial ice-stream stability in the Weddell1 Sea embayment, Antarctica2 3 Andrew S-level rise from Antarctica; it helps explain observed anomalies34 in glacio-isostatic adjustment; above all they drain the bulk of ice from Antarctica. Most ice streams in Antarctica46 lead into floating ice

  10. The impact of marginal ice zone processes on the distribution of 21OPb, 21OPo and 234Th and implications for new production in the Bellingshausen Sea, Antarctica

    Microsoft Academic Search

    Graham B. Shimmield; George D. Ritchie; Timothy W. Fileman

    1995-01-01

    The vertical distributions of 21OPb, 210Po and 234Th in both dissolved and particulate phases of seawater were measured at five stations along the 85°W meridian in the Bellingshausen Sea, Antarctica. Sea-ice conditions during the expedition ranged from fully ice-covered (fast ice) to open water away from the marginal ice zone. Concurrent primary productivity and algal chlorophyll measurements revealed a band

  11. Ecological role of Phyllophora antarctica drift accumulations in coastal soft-sediment communities of McMurdo Sound, Antarctica

    Microsoft Academic Search

    Alf Norkko; Simon F. Thrush; Vonda J. Cummings; Greig A. Funnell; Anne-Maree Schwarz; Neil L. Andrew; Ian Hawes

    2004-01-01

    At Cape Evans on Ross Island, Antarctica, the rhodophyte Phyllophora antarctica is the dominant primary producer in terms of biomass from 10 to >30 m depth. The vast majority of Phyllophora occurs as accumulations of unattached plants. Whilst decomposition and incorporation of macroalgal drift material into the food web is rapid in temperate ecosystems, we predicted these processes to be slow

  12. Recent Controlled Meteorological Balloon experiments in Queen Maud Land, Antarctica

    NASA Astrophysics Data System (ADS)

    Hole, L. R.; Voss, P. B.; Vihma, T. P.

    2013-12-01

    Controlled Meteorological (CMET) balloons are unique in that their altitude can be changed at any time during flight. They are remotely controlled via the Iridium network and use GPS for positioning. Over the past seven years, they have been operated at altitudes from sea-level to six kilometers and have flown for periods as long as five days. Campaigns have been carried out from the Amazon via Mexico City to polar regions. CMET balloons can perform repeated soundings in order to probe evolving thermal and chemical structure, measure wind shear, and track atmospheric layers. Typical ascent/descent rate is 1 m/s and the data sampling rate is 10 sec. The standard CMET balloon consists of zero-pressure balloon (~300-500 liters at sea level) which itself contains a much smaller (~100 liter) super-pressure balloon. Transferring helium between the super-pressure balloon and the zero-pressure balloon regulates the volume (and density) of the system, leading to controlled ascent and descent. Due to the rarity of meteorological observations from the Antarctic, especially from inland and over the sea, CMET balloons have potential to provide strongly needed data for evaluation of numerical weather prediction and climate models. Here, we present data from a CMET campaign carried out at the Finnish Aboa station in Antarctica (73° 03' S, 13° 25' W) in January 2013. The campaign was unique in that three CMET balloons were shipped to the station and launched by the local team. After the launch, they were controlled by scientists located in MA, USA and Norway. One balloon, Bravo, cruised for more than 100 hours over the coastal slopes of Queen Maud Land and nearby sea ice with a total trajectory length of over 3000 km (Fig. 1). It also passed nearby the UK Halley station. The altitude was generally kept at about 3000-3500 masl, but 8 controlled soundings down to 400-500 masl were carried out. The balloon data were compared with the Weather Research and Forecasting model (WRF) simulations using one domain with 2km horizontal resolution and the Yonsei University boundary layer scheme which has proven robust in Arctic and Antarctic applications. Significant discrepancies are revealed in both temperature and relative humidity. Few other measurements with high time resolution exist in the free troposphere in this region, but large discrepancies between observations and models were also observed by others such as Tastula and Vihma, (2011). In this presentation we attempt to find reasons why the WRF model is not able to reproduce the observed atmospheric structure and we also compare our measurements with radiosonde observations from Halley. Fig 1: Trajectory of the Bravo flight 18-23 January.

  13. Nd-Hf isotope systematics around Antarctica

    NASA Astrophysics Data System (ADS)

    van de Flierdt, T.; Roy, M.; Hemming, S. R.; Goldstein, S. L.; Abouchami, W.

    2004-12-01

    The motivation to study Nd-Hf systematics around Antarctica is twofold. First of all, a wide range of bedrock ages and lithologies are found around the perimeter of the Antarctic continent, ranging from Archean basement terrains to recent volcanics. However, in Nd-Hf isotope space Antarctica remains one of the poorly known regions of the world's continents. A first order characterization of Nd and Hf isotopes in the detrital fraction of marine sediments will fill this gap and will put additional constraints on Antarctic bedrock geology and isotope systematics. Preliminary data indicate a range of Nd isotopes from -1 to -19 and a range of Hf isotopes from -2 to -20. These values reflect the variable Antarctic provenance and follow local geology. The lowest values are found in the Indian Ocean sector close to Archean outcrops and the highest values are observed in the Pacific sector close to young bedrock ages in the region between the Ross Sea and the Antarctic Peninsula. In Nd-Hf isotope space the new data scatter around the terrestrial correlation line. Two samples from the Indian sector display more radiogenic Hf isotopes for a given Nd isotopic composition, pointing towards potentially different Nd-Hf isotope systematics for the sediments with old provenance. Second, detrital inputs from Antarctica get dispersed into the Antarctic Circumpolar Current (ACC). The ACC is the connection between the Pacific, Atlantic, and Indian Oceans and distributes deep waters formed in the North Atlantic as well as exports deep water generated at sites around Antarctica. It is however not known whether there exists significant transfer of dissolved Nd and Hf from the Antarctic continent to the ACC and ultimately to the world's ocean. An improved understanding of the composition of Southern Ocean water masses and their dependence on inputs from the Antarctic continent and deep water sources on the Antarctic shelf is an important precondition to unravel past global circulation patterns and material inputs to the ocean. We will present new Hf isotope data for ferromanganese nodules from the ACC, which will be compared with existing Nd isotope data. Preliminary results indicate a small range in Hf isotopes for the Pacific sector of the ACC (3.9 to 4.5), which is almost indistinguishable within the analytical error and matches with what would have been predicted from Nd-Hf isotope systematics in seawater.

  14. Autonomous Observations in Antarctica with AMICA

    E-print Network

    Di Rico, Gianluca; Dolci, Mauro; Straniero, Oscar; Valentini, Angelo; Valentini, Gaetano; Di Cianno, Amico; Giuliani, Croce; Magrin, Demetrio; Bonoli, Carlotta; Bortoletto, Favio; D'Alessandro, Maurizio; Corcione, Leonardo; Riva, Alberto

    2010-01-01

    The Antarctic Multiband Infrared Camera (AMICA) is a double channel camera operating in the 2-28 micron infrared domain (KLMNQ bands) that will allow to characterize and exploit the exceptional advantages for Astronomy, expected from Dome C in Antarctica. The development of the camera control system is at its final stage. After the investigation of appropriate solutions against the critical environment, a reliable instrumentation has been developed. It is currently being integrated and tested to ensure the correct execution of automatic operations. Once it will be mounted on the International Robotic Antarctic Infrared Telescope (IRAIT), AMICA and its equipment will contribute to the accomplishment of a fully autonomous observatory.

  15. M Station, Austin 

    E-print Network

    Mathon, S.

    2011-01-01

    SS WE EA MR EQ AE LEED Platinum (M Station) M Station 81 10849 $0.00/sf 100% Native Plants 76 $1.00/sf (total) ID LL SS WE EA MR EQ AE LEED Platinum (M Station) M Station 81 10849 $0.00/sf 100% Native Plants Concrete Paving 76 $1....00/sf (total) ID LL SS WE EA MR EQ AE LEED Platinum (M Station) M Station 81 10849 $0.00/sf 100% Native Plants Concrete Paving Pervious Concrete Sidewalks 76 $1.00/sf (total) ID LL SS WE EA MR EQ AE LEED Platinum (M Station) M Station 81...

  16. Accumulation Variability and Wind-borne Snow Transport Across Lyddan Ice Rise, Antarctica

    NASA Astrophysics Data System (ADS)

    King, J. C.; Anderson, P. S.; Vaughan, D. G.; Mann, G. W.; Mobbs, S. D.; Vosper, S. B.

    2004-12-01

    Redistribution of snow by the wind is the major contributor to spatial variability in snow accumulation over Antarctica on scales from metres to a few kilometres. Even small variations in wind speed associated with very gentle topography can give rise to large accumulation variations as a result of the highly nonlinear relationship between wind speed and snow transport. In this talk we examine the relationships between wind, topography and snow accumulation using observations made across an Antarctic ice rise. Lyddan Ice Rise is an approximately two-dimensional ridge, about 15 km wide, that rises 130m above the surrounding ice shelves. Surveys carried out using conventional stake measurements and ground penetrating radar reveal surprisingly large accumulation variations across this relatively gentle feature. On the scale of the ice rise itself, there is a gradual decline in accumulation moving from the ice shelf on the climatologically-upwind side to the climatologically downwind slope, where accumulation is reduced to around 65% of its upwind value. Superimposed on this broad-scale gradient are large (20-30%), localized variations in accumulation on a scale of around 1 km that appear to be associated with local variations in surface slope of around 0.01. The observed variations in accumulation agree well with calculations of snow redistribution made using wind measurements from automatic weather stations and winds derived from an airflow model, lending support to the hypothesis that snow redistribution is the major control on accumulation at this location. We discuss how our observations may relate to studies of accumulation variability in other parts of Antarctica, particularly the "megadune" fields of East Antarctica.

  17. What Hazards Do Humans Encounter in Antarctica?

    NSDL National Science Digital Library

    After investigating the challenges of living and working in Antarctica and how researchers prepare for them, students evaluate the insulating properties of a variety of fabrics. Throughout this six-day unit, they 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; an online activity in which students review the preparation materials given to researchers before traveling to Antarctica; two classroom activities,an experiment to test the insulation and waterproof properties of a variety of fabrics, and a Jeopardy-style game in which students write the answers and questions; several readings that provide a broad perspective, including an excerpt from Edmund Hillary's journal and Q&A interviews with a safety engineer and a field support services manager. A student handout with guidance for putting together their portfolios and examples of creative final projects is included.

  18. Climatic signals from 76 shallow firn cores in Dronning Maud Land, East Antarctica

    NASA Astrophysics Data System (ADS)

    Altnau, S.; Schlosser, E.; Isaksson, E.; Divine, D.

    2014-12-01

    The spatial and temporal distribution of surface mass balance (SMB) and ?18O were investigated in the first comprehensive study of a set of 76 firn cores retrieved by various expeditions during the past three decades in Dronning Maud Land, East Antarctica. The large number of cores was used to calculate stacked records of SMB and ?18O, which considerably increased the signal-to-noise ratio compared to earlier studies and facilitated the detection of climatic signals. Considerable differences between cores from the interior plateau and the coastal cores were found. The ?18O of both the plateau and the ice shelf cores exhibit a slight positive trend over the second half of the 20th century. In the corresponding period, the SMB has a negative trend in the ice shelf cores, but increases on the plateau. Comparison with meteorological data from Neumayer Station revealed that for the ice shelf regions atmospheric dynamic effects are more important than thermodynamics, while on the plateau, the temporal variations of SMB and ?18O occur mostly in parallel, thus can be explained by thermodynamic effects. The Southern Annular Mode (SAM) exhibits a positive trend since the mid-1960s, which is assumed to lead to a cooling of East Antarctica. This is not confirmed by the firn core data in our data set. Changes in the atmospheric circulation that result in a changed seasonal distribution of precipitation/accumulation could partly explain the observed features in the ice shelf cores.

  19. Climatic signals from 76 shallow firn cores in Dronning Maud Land, East Antarctica

    NASA Astrophysics Data System (ADS)

    Altnau, S.; Schlosser, E.; Isaksson, E.; Divine, D.

    2015-05-01

    The spatial and temporal distribution of surface mass balance (SMB) and ?18O were investigated in the first comprehensive study of a set of 76 firn cores retrieved by various expeditions during the past 3 decades in Dronning Maud Land, East Antarctica. The large number of cores was used to calculate stacked records of SMB and ?18O, which considerably increased the signal-to-noise ratio compared to earlier studies and facilitated the detection of climatic signals. Considerable differences between cores from the interior plateau and the coastal cores were found. The ?18O of both the plateau and the ice shelf cores exhibit a slight positive trend over the second half of the 20th century. In the corresponding period, the SMB has a negative trend in the ice shelf cores, but increases on the plateau. Comparison with meteorological data from Neumayer Station revealed that for the ice shelf regions, atmospheric dynamic effects are more important than thermodynamics while on the plateau; the temporal variations of SMB and ?18O occur mostly in parallel, and thus can be explained by thermodynamic effects. The Southern Annular Mode (SAM) has exhibited a positive trend since the mid-1960s, which is assumed to lead to a cooling of East Antarctica. This is not confirmed by the firn core data in our data set. Changes in the atmospheric circulation that result in a changed seasonal distribution of precipitation/accumulation could partly explain the observed features in the ice shelf cores.

  20. Testing reanalysis datasets in Antarctica: Trends, persistence properties and trend significance

    E-print Network

    Wang, Yang; Havlin, Shlomo

    2015-01-01

    The reanalysis datasets provide very important sources for investigating the climate dynamics and climate changes in Antarctica. In this paper, three major reanalysis data are compared with Antarctic station data over the last 35 years: the National Centers for Environmental Prediction and the National Center for Atmospheric Research reanalysis (NCEP1), NCEP-DOE Reanalysis 2 (NCEP2), and the European Centre for Medium-Range Weather Forecasts Interim Re-Analysis (ERA-Interim). In our assessment, we compare the linear trends, the fluctuations around the trends, the persistence properties and the significance level of warming trends in the reanalysis data with the observational ones. We find that NCEP1 and NCEP2 show spurious warming trends in all parts of Antarctica except the Peninsula, while ERA-Interim is quite reliable except at Amundsen-Scott. To investigate the persistence of the data sets, we consider the lag-1 autocorrelation $C(1)$ and the Hurst exponent. While $C(1)$ varies quite erratically in differ...

  1. The influence of phytoplankton assemblage composition on biogeochemical characteristics and cycles in the southern Ross Sea, Antarctica

    NASA Astrophysics Data System (ADS)

    Smith, Walker O.; Asper, Vernon L.

    2001-01-01

    To test the hypothesis that phytoplankton assemblages dominated by different taxa have distinct biogeochemical characteristics and cycles, the temporal and spatial variations in phytoplankton biomass and composition were studied within the Ross Sea polynya, where diatoms and the haptophyte Phaeocystis antarctica are thought to have spatially distinct distributions. Two cruises were completed, with the first conducted in spring, 1994, and the second in late spring-early summer, 1995/1996. Ice concentrations decreased substantially from spring to summer. Mixed layer depths for the region decreased markedly in early spring and were relatively invariant thereafter; the strength of the stratification varied both in time and space. Mixed layers were greater in spring in assemblages dominated by diatoms (as determined by HPLC pigment concentrations) than those dominated by Phaeocystis antarctica, whereas in summer no difference was observed. Nutrient concentrations were initially high and near winter values, but decreased throughout November and December. Nitrate : phosphate removal ratios varied widely, with ratios exceeding 20 in spring but decreasing below 14 in summer. N : P removal ratios at stations dominated by diatoms were less than the Redfield ratio in both spring and summer, and at those stations dominated by P. antarctica the N : P removal ratio was ca. 19 in both seasons. Chlorophyll and particulate matter concentrations increased as nutrients decreased. Spatial and temporal variations of phytoplankton pigments occurred, with 19'-hexanoylfucoxanthin, a pigment of P. antarctica, exceeding 3.9 ?g l -1 during spring in the south-central polynya, and fucoxanthin, an accessory pigment of diatoms, found in concentrations >1 ?g l -1 in the western Ross Sea. The distributions were not mutually exclusive, and concentrations of both pigments were greatest in spring. The early growth of P. antarctica appears to be related to earlier stratification and disappearance of ice from the south-central Ross Sea. Ratios of FUCO/CHL were relatively invariant, but substantial changes in the HEX/CHL and POC/CHL ratios were observed through time. A one-dimensional nitrogen budget for the spring-early summer period suggests that much of the surface production was partitioned into particles, most (53%) of which remained in the upper 200 m. The rest was partitioned into dissolved organic matter (14%), remineralized as ammonium (19%), or sank from the surface layer as particles (13%). The region may serve as a useful analog to other polar systems, and an understanding of the processes controlling assemblage composition, production, and biomass accumulation may provide insights into biogeochemical cycles of other Antarctic environments.

  2. Space Station Spartan study

    NASA Technical Reports Server (NTRS)

    Lane, J. H.; Schulman, J. R.; Neupert, W. M.

    1985-01-01

    The required extension, enhancement, and upgrading of the present Spartan concept are described to conduct operations from the space station using the station's unique facilities and operational features. The space station Spartan (3S), the free flyer will be deployed from and returned to the space station and will conduct scientific missions of much longer duration than possible with the current Spartan. The potential benefits of a space station Spartan are enumerated. The objectives of the study are: (1) to develop a credible concept for a space station Spartan; and (2) to determine the associated requirements and interfaces with the space station to help ensure that the 3S can be properly accommodated.

  3. Determination of integrated water vapor over Antarctica utilizing special sensor microwave temperature-2 (SSM/T- 2) data

    NASA Astrophysics Data System (ADS)

    Stephenson Moore, Stepheni Lyn

    Determining water vapor accurately over Antarctica is necessary to understand the global energy cycle. Water vapor over Antarctica plays a significant role in local energy balance, thus affecting outgoing longwave radiation, which, in turn, affects the global energy balance. Conventional radiosonde data and station data are relatively scarce compared to satellite data and are commonly used in weather analyses or climate first-guess fields. Therefore, a radiative transfer model has been developed from first principles in atmospheric physics to determine integrated water vapor over Antarctica utilizing brightness temperatures from two channels of the Special Sensor Microwave Temperature-2 (SSM/T-2) instrument, the 183.31 ± 3 GHz and 183.31 ± 7 GHz channels. Results indicate that the satellite water vapor retrievals are capable of rendering more accurate water vapor fields and weather not previously seen in ECMWF analyses, including the characteristic comma-shaped cyclonic activity, thus serving to improve present understanding of weather and climate over Antarctica. The relationship between retrieved water vapor and surface temperature has also been determined for July, 1994. Mean integrated water vapor data are sorted in 1 K surface temperature increments and plotted against the surface temperature, in an effort to provide a relationship for use in climate and weather models. Mean integrated water vapor values range from 250 g/m2 (0.25 mm) over the interior of the continent to 3000 g/m2 (3 mm) over the coastline. A discussion of standard deviation in retrieved water vapor averages as well as total standard deviation is also presented. In addition sample retrieved reflectivity values are presented.

  4. It?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...

  5. IT?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...

  6. IDENTIFICATION OF A PSYCHROPHILIC GREEN ALGA FROM LAKE BONNEY ANTARCTICA: CHLAMYDOMONAS RAUDENSIS ETTL. (UWO 241) CHLOROPHYCEAE1

    E-print Network

    Priscu, John C.

    IDENTIFICATION OF A PSYCHROPHILIC GREEN ALGA FROM LAKE BONNEY ANTARCTICA: CHLAMYDOMONAS RAUDENSIS: Antarctica; Chlamydomonas; Chla- mydomonas hedleyi; Chlamydomonas noctigama; Chlamydomonas raudensis Abbreviations: ITS, internal transcribed spacer; SSU, ribosomal small subunit Antarctica consists of many harsh

  7. Lidar observations of polar stratospheric clouds at McMurdo, Antarctica, during NOZE-2

    NASA Technical Reports Server (NTRS)

    Morley, Bruce M.

    1988-01-01

    SRI International operated a dual wavelength (1.064 micrometer and .532 micrometer) aerosol lidar at McMurdo Station, Antarctica, as part of the National Ozone Expedition-2 (NOZE-2). The objective of the project was to map the vertical distributions of polar stratospheric clouds (PSCs), which are believed to play an important role in the destruction of ozone in the Antarctic spring. Altitude, thickness, homogeneity, and duration of PSC events as well as information on particle shape, size or number density will be very useful in determining the exact role of PSCs in ozone destructions, and when combined with measurements of other investigators, additional properties of PSCs can be estimated. The results are currently being analyzed in terms of PSC properties which are useful for modeling the stratospheric ozone depletion mechanism.

  8. Complete mitochondrial genome of the South Polar Skua Stercorarius maccormicki (Charadriiformes, Stercorariidae) in Antarctica.

    PubMed

    Han, Yeong-Deok; Baek, Ye-Seul; Kim, Jeong-Hoon; Choi, Han-Gu; Kim, Sanghee

    2014-09-30

    Abstract The South Polar Skua, gull-like seabirds is the most fascinating Antarctic seabirds that lay two eggs at sites free of snow and ice and predominantly hunt pelagic fish and penguins. Blood samples of the South Polar Skua Stercorarius maccormicki was collected during the summer activity near King Sejong station in Antarctica. The complete mitochondrial DNA sequence of S. maccormicki was 16,669?bp, showing conserved genome structure and orientation found in other avian species. The control region of S. maccormicki was 93- and 80?bp shorter compared to those of Chroicocephalus saundersi and Synthliboramphus antiquus respectively. Interestingly, there is a (CAACAAACAA)6 repeat sequence in the control region. Our results of S. maccormicki mt genome including the repeat sequence, may provide useful genetic information for phylogenetic and phylogeographic histories of the southern skua complex. PMID:25268998

  9. Birth of a Large Iceberg in Pine Island Bay, Antarctica

    NSDL National Science Digital Library

    2004-10-02

    This lithograph shows the break-off of a large iceberg from the Pine Island Glacier in West Antarctica. This event occurred between November 4th and 12th, 2001, and provides powerful evidence of rapid changes underway in this area of Antarctica. The three images presented were acquired by the vertical-viewing (nadir) camera of the Multi-angle Imaging SpectroRadiometer (MISR) instrument aboard NASA's Terra spacecraft.

  10. Development of long-duration ballooning in Antarctica

    SciTech Connect

    Jones, W.V. (National Aeronautics and Space Administration, Code ES, Space Physics Division, Washington, DC 20546 (USA))

    1990-03-20

    Following four successful long-duration test flights from Australia to South America, a new flight support system with global tracking, command, and telemetry capability is being developed to support long-duration balloon flights of relatively sophisticated instruments at both mid-latitudes and in Antarctica. The first test flight for the joint NASA-NSF program to support flights in Antarctica is scheduled from McMurdo in December 1989, with operational capability two years later.

  11. A possible endogonaceous fungus from the Triassic of Antarctica

    E-print Network

    Stubblefield, Sara P.; Taylor, Thomas N.; Seymour, Roland L.

    1987-01-05

    Department of Botany, The Ohio State University, Columbus, Ohio 43210 A possible endogonaceous fungus has recently been discovered in a silicified matrix from the Triassic of Antarctica. Material was collected from the Fremouw Peak Formation near Fre...-mouw Peak in the Beardmore Glacier region of Antarctica in conjunction with the Byrd Polar Research Center at The Ohio State University. The matrix is early-middle Triassic (Collinson et al., 1980). Specimens bear collection numbers 17,442-17,451 in The Ohio...

  12. A Possible Endogonaceous Fungus from the Triassic of Antarctica

    E-print Network

    Stubblefield, Sara P.; Taylor, Thomas N.; Seymour, Roland L.

    1987-11-01

    Department of Botany, The Ohio State University, Columbus, Ohio 43210 A possible endogonaceous fungus has recently been discovered in a silicified matrix from the Triassic of Antarctica. Material was collected from the Fremouw Peak Formation near Fre...-mouw Peak in the Beardmore Glacier region of Antarctica in conjunction with the Byrd Polar Research Center at The Ohio State University. The matrix is early-middle Triassic (Collinson et al., 1980). Specimens bear collection numbers 17,442-17,451 in The Ohio...

  13. Photosynthesis-irradiance responses in the Ross Sea, Antarctica: a meta-analysis

    NASA Astrophysics Data System (ADS)

    Smith, W. O., Jr.; Donaldson, K.

    2015-06-01

    A meta-analysis of photosynthesis-irradiance measurements was completed using data from the Ross Sea, Antarctica, using a total of 417 independent measurements. PmB, the maximum, chlorophyll-specific, irradiance-saturated rate of photosynthesis, averaged 1.1 ± 0.06 ?g C (?g Chl)-1 h-1. Light-limited, chlorophyll-specific photosynthetic rates (?B) averaged 0.030 ± 0.023 ?g C (?g Chl)-1 h-1 (?mol quanta m-2 s-1)-1. Significant variations in PmB and ?B were found as a function of season, with spring maximum photosynthetic rates being 60% greater than those in summer. Similarly, ? values were 48% greater in spring. There was no detectable effect of sampling location on the photo-synthetic parameters, and temperature and macronutrient (NO3) concentrations also did not have an influence. However, irradiance and carbon dioxide concentrations, when altered under controlled conditions, exerted significant influences on photosynthetic parameters. Specifically, reduced irradiance resulted in significantly decreased PmB and increased ?B values, and increased CO2 concentrations resulted in significantly increased PmB and ?B values. Comparison of photosynthetic parameters derived at stations where iron concentrations were above and below 0.1 nM indicated that reduced iron levels were associated with significantly increased PmB values, confirming the importance of iron within the photosynthetic process. No significant difference was detected between stations dominated by diatoms and those dominated by the haptophyte Phaeocystis antarctica. The meta-analysis confirms the photosynthetic rates predicted from global analyses that are based solely on temperature and irradiance availability, but suggests that, for more accurate predictions of productivity in polar systems, a more detailed model that includes temporal effects of photosynthetic parameters will be required.

  14. Iceberg B-15, Ross Ice Shelf, Antarctica

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Iceberg B-15 broke from the Ross Ice Shelf in Antarctica in late March. Among the largest ever observed, the new iceberg is approximately 170 miles long x 25 miles wide. Its 4,250 square-mile area is nearly as large as the state of Connecticut. The iceberg was formed from glacial ice moving off the Antarctic continent and calved along pre-existing cracks in the Ross Ice Shelf near Roosevelt Island. The calving of the iceberg essentially moves the northern boundary of the ice shelf about 25 miles to the south, a loss that would normally take the ice shelf as long as 50-100 years to replace. This infrared image was acquired by the DMSP (Defense Meteorological Satellite Program) F-13 satellite on April 13, 2000. For more images see Antarctic Meteorological Research Center Image courtesy of the University of Wisconsin - Madison, Space Science and Engineering Center, Antarctic Meteorological Research Center

  15. Ice-Shelf Melting Around Antarctica

    NASA Astrophysics Data System (ADS)

    Rignot, E.; Jacobs, S.; Mouginot, J.; Scheuchl, B.

    2013-07-01

    We compare the volume flux divergence of Antarctic ice shelves in 2007 and 2008 with 1979 to 2010 surface accumulation and 2003 to 2008 thinning to determine their rates of melting and mass balance. Basal melt of 1325 ± 235 gigatons per year (Gt/year) exceeds a calving flux of 1089 ± 139 Gt/year, making ice-shelf melting the largest ablation process in Antarctica. The giant cold-cavity Ross, Filchner, and Ronne ice shelves covering two-thirds of the total ice-shelf area account for only 15% of net melting. Half of the meltwater comes from 10 small, warm-cavity Southeast Pacific ice shelves occupying 8% of the area. A similar high melt/area ratio is found for six East Antarctic ice shelves, implying undocumented strong ocean thermal forcing on their deep grounding lines.

  16. Photometry of Variables from Dome A, Antarctica

    NASA Astrophysics Data System (ADS)

    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

    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.

  17. Mass Casualty Incident Response and Aeromedical Evacuation in Antarctica

    PubMed Central

    Mills, Christopher N.; Mills, Gregory H.

    2011-01-01

    Antarctica is one of the most remote regions on Earth. Mass casualty incident (MCI) responses in Antarctica are prone to complications from multiple environmental and operational challenges. This review of the current status of MCI risks and response strategies for Antarctica focuses on aeromedical evacuation, a critical component of many possible MCI scenarios. Extreme cold and weather, a lack of medical resources and a multitude of disparate international bases all exert unique demands on MCI response planning. Increasing cruise ship traffic is also escalating the risk of MCI occurrence. To be successful, MCI response must be well coordinated and undertaken by trained rescuers, especially in the setting of Antarctica. Helicopter rescue or aeromedical evacuation of victims to off-continent facilities may be necessary. Currently, military forces have the greatest capacity for mass air evacuation. Specific risks that are likely to occur include structure collapses, vehicle incapacitations, vehicle crashes and fires. All of these events pose concomitant risks of hypothermia among both victims and rescuers. Antarctica’s unique environment requires flexible yet robust MCI response planning among the many entities in operation on the continent. PMID:21691470

  18. Ice-shelf melting around Antarctica

    NASA Astrophysics Data System (ADS)

    Rignot, E.; Jacobs, S.

    2008-12-01

    The traditional view on the mass balance of Antarctic ice shelves is that they loose mass principally from iceberg calving with bottom melting a much lower contributing factor. Because ice shelves are now known to play a fundamental role in ice sheet evolution, it is important to re-evaluate their wastage processes from a circumpolar perspective using a combination of remote sensing techniques. We present area average rates deduced from grounding line discharge, snow accumulation, firn depth correction and ice shelf topography. We find that ice shelf melting accounts for roughly half of ice-shelf ablation, with a total melt water production of 1027 Gt/yr. The attrition fraction due to in-situ melting varies from 9 to 90 percent around Antarctica. High melt producers include the Ronne, Ross, Getz, Totten, Amery, George VI, Pine Island, Abbot, Dotson/Crosson, Shackleton, Thwaites and Moscow University Ice Shelves. Low producers include the Larsen C, Princess Astrid and Ragnhild coast, Fimbul, Brunt and Filchner. Correlation between melt water production and grounding line discharge is low (R2 = 0.65). Correlation with thermal ocean forcing from the ocean are highest in the northern parts of West Antarctica where regressions yield R2 of 0.93-0.97. Melt rates in the Amundsen Sea exhibit a quadratic sensitivity to thermal ocean forcing. We conclude that ice shelf melting plays a dominant role in ice shelf mass balance, with a potential to change rapidly in response to altered ocean heat transport onto the Antarctic continental shelf.

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

    NASA Technical Reports Server (NTRS)

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

    1987-01-01

    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.

  20. The Shorthorn: Casey Crane Robert Arrowood, Carrizo Oil and Gas, Inc. representative, takes local homeowners' questions about on-campus natural gas drilling in an Arlington office complex Tuesday.

    E-print Network

    Chiao, Jung-Chih

    that plans to drill on university property. Carrizo Oil and Gas, Inc. recently signed a one-year leaseThe Shorthorn: Casey Crane Robert Arrowood, Carrizo Oil and Gas, Inc. representative, takes local homeowners' questions about on-campus natural gas drilling in an Arlington office complex Tuesday. Jenna

  1. What Gets Measured Gets Done: High Priority Opportunities to Improve Our Nation's Capacity to Monitor Child and Youth Well-Being. A White Paper for the Annie E. Casey Foundation

    ERIC Educational Resources Information Center

    Brown, Brett; Moore, Kristin Anderson

    2009-01-01

    Child Trends has been asked by the Annie E. Casey Foundation to identify key opportunities that a new Administration might pursue to improve the capacity of the federal statistical system to monitor child and youth well-being. In this paper the authors discuss a number of areas of opportunity, offering concrete steps that can be taken, generally…

  2. Monitoring Isostatic Rebound in Antarctica with the Use of Continuous Remote GPS Observations

    E-print Network

    Tregoning, Paul

    Monitoring Isostatic Rebound in Antarctica with the Use of Continuous Remote GPS Observations PAUL-powered GPS receiver has been installed near Beaver Lake,Antarctica, to monitor postglacial isostatic rebound rebound of

  3. Dive and Discover Antarctica Computer Lab Sheet www.divediscover.whoi.edu

    E-print Network

    Oppo, Delia W.

    for the Expedition 10 Antarctica? 2. Click on "Read the daily update". In the left-hand list, click on "MissionDive and Discover Antarctica Computer Lab Sheet www.divediscover.whoi.edu 1. What are the dates

  4. Radio spectrum surveillance station

    Microsoft Academic Search

    D. R. Hersey

    1979-01-01

    The paper presents a general and functional description of a low-cost surveillance station designed as the first phase of NASA's program to develop a radio spectrum surveillance capability for deep space stations for identifying radio frequency interference sources. The station described has identified several particular interferences and is yielding spectral signature data which, after cataloging, will serve as a library

  5. Southwestern Research Station

    NSDL National Science Digital Library

    This Web site profiles AMNH's Southwestern Research Station (SWRS), a year-round field station that allows biologists, geologists, and anthropologists to study the diverse environments and biotas of the Chiricahua Mountains in southeastern Arizona. The site includes an overview of the field station and its work, information on courses offered, and information for visitors, researchers, interns and volunteers.

  6. Space Station - early

    NASA Technical Reports Server (NTRS)

    1962-01-01

    James Hansen wrote: 'Langley engineers check out the interior of the inflatable 24-foot space station in January 1962.'... 'The first idea for an inflatable station was the Erectable Torus Manned Space Laboratory. A Langley space station team led by Paul Hill and Emanuel 'Manny' Schnitzer developed the concept with the help of the Goodyear Aircraft Corporation.'

  7. An Antarctic research station as a source of brominated and perfluorinated persistent organic pollutants to the local environment.

    PubMed

    Wild, Seanan; McLagan, David; Schlabach, Martin; Bossi, Rossana; Hawker, Darryl; Cropp, Roger; King, Catherine K; Stark, Jonathan S; Mondon, Julie; Nash, Susan Bengtson

    2015-01-01

    This study investigated the role of a permanently manned Australian Antarctic research station (Casey Station) as a source of contemporary persistent organic pollutants (POPs) to the local environment. Polybrominated diphenyl ethers (PBDEs) and poly- and perfluoroalkylated substances (PFASs) were found in indoor dust and treated wastewater effluent of the station. PBDE (e.g., BDE-209 26-820 ng g(-1) dry weight (dw)) and PFAS levels (e.g., PFOS 3.8-2400 ng g(-1) (dw)) in dust were consistent with those previously reported in homes and offices from Australia, reflecting consumer products and materials of the host nation. The levels of PBDEs and PFASs in wastewater (e.g., BDE-209 71-400 ng L(-1)) were in the upper range of concentrations reported for secondary treatment plants in other parts of the world. The chemical profiles of some PFAS samples were, however, different from domestic profiles. Dispersal of chemicals into the immediate marine and terrestrial environments was investigated by analysis of abiotic and biotic matrices. Analytes showed decreasing concentrations with increasing distance from the station. This study provides the first evidence of PFAS input to Polar regions via local research stations and demonstrates the introduction of POPs recently listed under the Stockholm Convention into the Antarctic environment through local human activities. PMID:25478728

  8. Controlling mechanisms of Thwaites Glacier, West Antarctica

    NASA Astrophysics Data System (ADS)

    Seroussi, H. L.; Morlighem, M.; Rignot, E. J.; Larour, E. Y.; Mouginot, J.; Khazendar, A.

    2013-12-01

    Ice shelves play a major role in the stability of fast flowing ice streams in Antarctica, by exerting buttressing on inland ice and controlling the discharge of ice into the ocean. However, the mechanisms at work remain poorly understood and interactions between floating and grounded ice need to be better characterized in order to estimate the impact of climate change on the ice sheets. Thwaites glacier, in West Antarctica, features a small and heavily fractured ice shelf that provides limited back stress pressure on inland ice but is pinned on the eastern part on a prominent ridge. Thwaites glacier has maintained a consistently high velocity and negative mass balance for at least 20 years. Recent observations show a widening of its fast flowing area as well as a sustained acceleration since 2006 and a rapid retreat of its grounding line in the center of the glacier. The objective of this work is to characterize the dynamic response of Thwaites glacier to changes in its floating tongue on decadal to centennial time scales. To achieve this objective, we rely on high resolution ice flow modeling and grounding line dynamics using the Ice Sheet System Model (ISSM). We will focus on the complex interplay between the main floating tongue of Thwaites Glacier and its eastern, slow moving ice shelf, which is pinned down by an ice rumple. The speed of the eastern ice shelf is strongly affected by the coupling with the main floating ice tongue, which results in significant fluctuations in speed of the eastern ice shelf the formation of ice shelf cracks at the grounding line during acceleration phases. Our results show that ice rigidity at the junction between the eastern and western part of the shelf controls the dynamic regime of the ice shelf and suggest that Thwaites Glacier is likely to undergo substantial changes in the coming decades. This work was performed at the California Institute of Technology's Jet Propulsion Laboratory and the University of California Irvine under a contract with the National Aeronautics and Space Administration, Cryospheric Sciences and Modeling, Analysis and Prediction Programs

  9. Origin of the inland Acari of Continental Antarctica, with particular reference to Dronning Maud Land

    Microsoft Academic Search

    PHILIP J. A. PUGH

    1996-01-01

    The extant Acari occurring on the inland mountain ranges and nunataks of Continental Antarctica comprise only pre-Pleistocene endemic Prostigmata and Cryptostigmata of which the Prostigmata are the probable earlier colonists. The inland acarofauna of Continental Antarctica has a different origin from that of Maritime Antarctica, though both are the relict descendants of a Mesozoic acarofauna, which has been radically depleted

  10. Climatology of katabatic winds in the McMurdo dry valleys, southern Victoria Land, Antarctica

    E-print Network

    Fountain, Andrew G.

    the early expeditions to Antarctica. At Cape Denison, Ade´lie Land, wind speeds were recorded in excessClimatology of katabatic winds in the McMurdo dry valleys, southern Victoria Land, AntarcticaMurdo dry valleys, Antarctica. Winter wind events can increase local air temperatures by 30°C. The frequency

  11. Implementation of Polar WRF for short range prediction of weather over Maitri region in Antarctica

    E-print Network

    Howat, Ian M.

    Indian expedition to Antarctica. Under the program (Pandey 2007), atmospheric, biological, earthImplementation of Polar WRF for short range prediction of weather over Maitri region in Antarctica is now named as `Bharati'. Antarctica (Schwedtfeger 1984) is the coldest, windiest, highest, driest

  12. Endoglucanase-producing fungi isolated from Cape Evans historic expedition hut on Ross Island, Antarctica

    Microsoft Academic Search

    Shona M. Duncan; Roberta L. Farrell; Joanne M. Thwaites; Benjamin W. Held; Brett E. Arenz; Joel A. Jurgens; Robert A. Blanchette

    2006-01-01

    Summary Early explorers of Antarctica's Heroic Era erected wooden buildings and brought large quantities of supplies to survive in Antarctica. The introduction of wood and other organic materials provided nutrient sources for fungi that were indigenous to Antarctica or were brought in with the materials and adapted to the harsh conditions. Seventy-two isolates of filamen- tous fungi were cultured on

  13. International Snow Science Workshop Grenoble Chamonix Mont-Blanc -2013 Simulations of blowing Snow over Antarctica

    E-print Network

    Paris-Sud XI, Université de

    Snow over Antarctica Hubert Gallée 1 , Alexandre Trouvilliez1,3 , Charles Amory 1 , Cécile Agosta 2 used to simulate transport of snow by the wind in Adélie Land, Antarctica, over a small domain (500 x that may be much larger than previously estimated. KEYWORDS: Climate Modeling, Antarctica, Snow Transport

  14. Tropical Pacific Influence on the Source and Transport of Marine Aerosols to West Antarctica*

    E-print Network

    Karnauskas, Kristopher

    Tropical Pacific Influence on the Source and Transport of Marine Aerosols to West Antarctica 2013) ABSTRACT The climate of West Antarctica is strongly influenced by remote forcing from the tropical Pacific. For example, recent surface warming over West Antarctica reflects atmospheric circulation

  15. Seismic stratigraphy of the Adare Trough area, Antarctica Joanne M. Whittaker , R. Dietmar Mller

    E-print Network

    Müller, Dietmar

    Seismic stratigraphy of the Adare Trough area, Antarctica Joanne M. Whittaker , R. Dietmar Müller May 2006; accepted 17 May 2006 Abstract The Adare Trough, located 100 km NE of Cape Adare, Antarctica, is the extinct third arm of a Tertiary spreading ridge that separated East from West Antarctica. We use seismic

  16. Ice Shelf Water plume flow beneath Filchner-Ronne Ice Shelf, Antarctica

    E-print Network

    Feltham, Daniel

    Ice Shelf Water plume flow beneath Filchner-Ronne Ice Shelf, Antarctica Paul R. Holland,1 Daniel L Filchner- Ronne Ice Shelf, Antarctica and its underlying ocean cavity. Ice Shelf Water (ISW) plumes-Ronne Ice Shelf, Antarctica, J. Geophys. Res., 112, C05044, doi:10.1029/2006JC003915. 1. Introduction [2

  17. Optical Flow and Scale-Space Theory applied to Sea-Ice Motion Estimation in Antarctica

    E-print Network

    Long, David G.

    Optical Flow and Scale-Space Theory applied to Sea-Ice Motion Estimation in Antarctica Salvador-- Sea-ice motion in Antarctica is studied applying methods from computer vision and scale-space theory-ice directions and speeds on Antarctica has been previously approached with correlation [1] or wavelet [2], [3

  18. Relative humidity over Antarctica from radiosondes, satellites, and a general circulation model

    E-print Network

    Walden, Von P.

    Relative humidity over Antarctica from radiosondes, satellites, and a general circulation model A to validate measurements of relative humidity (RH) over Antarctica from the Atmospheric Infrared Sounder (AIRS over Antarctica is well reproduced by the satellite. AIRS data are also compared to simulations from

  19. Soil Biology & Biochemistry 38 (2006) 30193034 Terrestrial ecosystem processes of Victoria Land, Antarctica

    E-print Network

    Wall, Diana

    2006-01-01

    , Antarctica J.E. Barretta,Ã, R.A. Virginiaa , D.W. Hopkinsb , J. Aislabiec , R. Bargaglid , J.G. Bockheime , I, Antarctica are ideal systems to test hypotheses about the sensitivity of ecosystem processes to climate in Victoria Land, Antarctica are constrained by combinations of extreme conditions includ- ing low

  20. Two-dimensional structure of long-period pulsations at polar latitudes in Antarctica

    E-print Network

    1 Two-dimensional structure of long-period pulsations at polar latitudes in Antarctica N.V. Yagova-periods about ten minutes are analyzed using data from magnetometer arrays in Antarctica. Examination of the 2D be monitored with ground-based magnetic observations at polar latitudes in Antarctica and the Arctic. Because

  1. Energetic consequences of repeated and prolonged dehydration in the Antarctic midge, Belgica antarctica

    E-print Network

    Lee Jr., Richard E.

    antarctica Nicholas M. Teets a, , Yuta Kawarasaki b , Richard E. Lee Jr. b , David L. Denlinger a of the Antarctic midge, Belgica antarctica, routinely face periods of limited water availability in their natural environments on the Antarctic Peninsula. As a result, B. antarctica is one of the most dehydration

  2. Application of Optical Flow and Scale Space Methods to Sea-Ice Motion in Antarctica

    E-print Network

    Long, David G.

    Application of Optical Flow and Scale Space Methods to Sea-Ice Motion in Antarctica Salvador Guti computer vision and scale-space theory are applied to the study of sea-ice motion in Antarctica. The input into account that there is practically no ground-truth data available for Antarctica in the form of buoy

  3. Snow grain-size measurements in Antarctica Michel GAY,1,2

    E-print Network

    Paris-Sud XI, Université de

    Snow grain-size measurements in Antarctica Michel GAY,1,2 Michel FILY,1 Christophe GENTHON,1-known characteristic of snow at the surface of Antarctica. In the past, grain-size has been reported using various-size distribution from fieldwork in Antarctica. In particular, except at sites affected by a very particular meteor

  4. Modified shelf water on the continental slope north of Mac Robertson Land, East Antarctica

    E-print Network

    Riser, Stephen C.

    Modified shelf water on the continental slope north of Mac Robertson Land, East Antarctica Annie P Antarctica. This bottom layer water mass, with potential temperature in the range À1.8°C source of dense waters in East Antarctica. Citation: Wong, A. P. S., and S. C. Riser (2013), Modified

  5. A New Species of Nototheniid (Perciformes: Notothenioidei) Fish from McMurdo Sound, Antarctica

    E-print Network

    Cheng, Chi-Hing Christina

    A New Species of Nototheniid (Perciformes: Notothenioidei) Fish from McMurdo Sound, Antarctica PAUL Sea region of Antarctica. The new species closely resembles the only known congener, C. peninsulae routine surveys at a heavily-sampled site in McMurdo Sound, Ross Sea, Antarctica happened upon a fish

  6. Seismic observations of sea swell on the floating Ross Ice Shelf, Antarctica

    E-print Network

    Boyce, C. Kevin

    Seismic observations of sea swell on the floating Ross Ice Shelf, Antarctica L. M. Cathles IV,1 by several orders of magnitude over the time period that sea ice surrounding Antarctica decreases from its of Alaska. These remote events emphasize how the iceberg calving margin of Antarctica is connected

  7. Seismic evidence for deep low-velocity anomalies in the transition zone beneath West Antarctica

    E-print Network

    Seismic evidence for deep low-velocity anomalies in the transition zone beneath West Antarctica in Antarctica that were all restricted to the analysis of the fundamental mode. This paper is therefore mostly Byrd Land, West Antarctica and a portion of the Pacific^ Antarctic Ridge close to the Balleny Islands

  8. The biogeochemistry of Si in the McMurdo Dry Valley lakes, Antarctica

    E-print Network

    Priscu, John C.

    The biogeochemistry of Si in the McMurdo Dry Valley lakes, Antarctica Heather E. Pugh1 *, Kathleen) of Antarctica. Our data and calculations indicate that biological uptake of Si is not a major process as in temperate systems. Accepted 1 October 2002 Key words: Antarctica, lakes, silica, biogeochemistry

  9. Understanding water effect on Candida antarctica lipase B activity and enantioselectivity towards

    E-print Network

    Paris-Sud XI, Université de

    1 Understanding water effect on Candida antarctica lipase B activity and enantioselectivity towardsW) on Candida antarctica lipase B (CALB) activity and enantioselectivity towards secondary alcohols was assessed that water has many effects on Candida antarctica lipase B (CALB) catalyzed enantioselective reactions

  10. Thickness of the Atmospheric Boundary Layer Above Dome A, Antarctica, during 2009

    E-print Network

    Ashley, Michael C. B.

    Thickness of the Atmospheric Boundary Layer Above Dome A, Antarctica, during 2009 C. S. BONNER,1 M s at Dome A, Antarctica between 2009 February 4 and 2009 August 18. The median thickness of the boundary increase. Winds within the boundary layer over Antarctica are usually katabatic in na- ture. This suggests

  11. A new high-latitude record for the macaroni penguin (Eudyptes chrysolophus) at Avian Island, Antarctica

    E-print Network

    Island, Antarctica K. B. Gorman · E. S. Erdmann · B. C. Pickering · P. J. Horne · J. R. Blum · H. M penguins (Eudyptes chrysolophus) on Avian Island, Antarctica, approximately 1° south of the Antarctic of Antarctica. We also report more frequent extra-l

  12. Surface mass balance and stable oxygen isotope ratios from shallow firn cores on Fimbulisen, East Antarctica

    E-print Network

    Schlosser, Elisabeth

    Antarctica E. SCHLOSSER,1 H. ANSCHU¨ TZ,2 E. ISAKSSON,3 T. MARTMA,4 D. DIVINE,5 O.-A. NØST3 1 Institute, Tromsø, Norway ABSTRACT. The mass balance of Antarctica is one of the crucial factors for determining sea was carried out on Fimbulisen, an ice shelf in East Antarctica, to investigate its recent surface mass balance

  13. LETTER doi:10.1038/nature11616 Increased future ice discharge from Antarctica owing

    E-print Network

    Levermann, Anders

    LETTER doi:10.1038/nature11616 Increased future ice discharge from Antarctica owing to higher snowfall over Antarctica, which would provide a direct offset of the future contribution to global sea Antarctica1,6 and thus in the ultimate fate of the precipitation- deposited ice mass. Here we show

  14. Geophysical models for the tectonic framework of the Lake Vostok region, East Antarctica

    E-print Network

    Levin, Vadim

    Geophysical models for the tectonic framework of the Lake Vostok region, East Antarctica Michael of East Antarctica were used to develop a conceptual tectonic model for the Lake Vostok region. The model a tectonic boundary within East Antarctica. Based on our kinematic and flexural gravity modelling

  15. The influence of Antarctica on the momentum budget of the southern

    E-print Network

    Wirosoetisno, Djoko

    The influence of Antarctica on the momentum budget of the southern extratropics 1234567 89A64BC7DEF.1(21~13):551.555.4:551.588.5(W) The influence of Antarctica on the momentum budget of the southern extratropics By M. N. JUCKES Antarctica reveals a balance between the Eliassen-Palm fluxconvergence and the Coriolistorque exerted

  16. CALIPSO observations of wave-induced PSCs with near-unity optical depth over Antarctica in

    E-print Network

    Boyer, Edmond

    CALIPSO observations of wave-induced PSCs with near-unity optical depth over Antarctica in 2006 Antarctica during the 2006 and 2007 austral winters. These clouds are rare (less than 1% of profiles with daily temperature minimas across Antarctica. Lidar and depolarization ratios within these clouds suggest

  17. S125JULY 2010STATE OFTHE CLIMATE IN 2009 | 6. ANTARCTICA

    E-print Network

    S125JULY 2010STATE OFTHE CLIMATE IN 2009 | 6. ANTARCTICA a. Overview--R. L. Fogt The calendar year 2009 was relatively calm, climatologically speaking, for much of Antarctica, especially compared, the tropical El Niño event in late 2009 did influence Antarctica, particularly through ridging in the South

  18. Aeolian flux of biotic and abiotic material in Taylor Valley, Antarctica Marie Saback a

    E-print Network

    Wall, Diana

    Aeolian flux of biotic and abiotic material in Taylor Valley, Antarctica Marie Sabacká a , John C Keywords: Aeolian Föhn Antarctica Biotic Abiotic Desert 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

  19. Rayleigh wave phase velocity analysis of the Ross Sea, Transantarctic Mountains, and East Antarctica

    E-print Network

    Antarctica from a temporary seismograph array Jesse F. Lawrence,1,2 Douglas A. Wiens,1 Andrew A. Nyblade,3 from the Ross Sea (RS) region of the West Antarctica rift system, the Transantarctic Mountains (TAMs), and part of East Antarctica (EA). The Transantarctic Mountain Seismic Experiment deployed 41 three

  20. Tuesday, January 7, 2014 | 04:39 PM IST Antarctica crust similar to South India,

    E-print Network

    Harinarayana, T.

    Tuesday, January 7, 2014 | 04:39 PM IST Antarctica crust similar to South India, Mozambique: study Press Trust of India | Ahmedabad November 25, 2013 Last Updated at 10:00 IST The crust of Antarctica Antarctica: a magnetotelluric study' published in international journal Polar Research earlier this month

  1. Accelerated thermokarst formation in the McMurdo Dry Valleys, Antarctica

    E-print Network

    Marchant, David R.

    Accelerated thermokarst formation in the McMurdo Dry Valleys, Antarctica Joseph S. Levy1 , Andrew G been considered to be a minor process in Antarctica. Here, we use ground-based and airborne Li accelerated in Garwood Valley, Antarctica; 2) the rate of thermokarst erosion is presently , 10 times

  2. Precipitation regime of Dronning Maud Land, Antarctica, derived from Antarctic Mesoscale

    E-print Network

    Schlosser, Elisabeth

    Precipitation regime of Dronning Maud Land, Antarctica, derived from Antarctic Mesoscale Prediction] The precipitation regime of Dronning Maud Land (DML), Antarctica, was studied using Antarctic Mesoscale Prediction, Antarctica, derived from Antarctic Mesoscale Prediction System (AMPS) archive data, J. Geophys. Res., 113, D

  3. RESEARCH/REVIEW ARTICLE Trampling on maritime Antarctica: can soil ecosystems be

    E-print Network

    Justel Eusebio, Ana

    RESEARCH/REVIEW ARTICLE Trampling on maritime Antarctica: can soil ecosystems be effectively.tejedo@uam.es Abstract Soil trampling is one of the most obvious direct negative human impacts in Antarctica. Through it necessary to revise existing codes of conduct. Antarctica is a vast continent with an area around 14 000 000

  4. Little Ice Age cold interval in West Antarctica: Evidence from borehole temperature at the West Antarctic

    E-print Network

    Severinghaus, Jeffrey P.

    Little Ice Age cold interval in West Antarctica: Evidence from borehole temperature at the West, especially in Antarctica. We present temperature data from a 300 m borehole at the West Antarctic Ice Sheet and West Antarctica suggests that the feedbacks amplifying the radiative forcing may not operate

  5. Microwave Wind Direction Retrieval over Antarctica David G. Long and Mark Drinkwater

    E-print Network

    Long, David G.

    Microwave Wind Direction Retrieval over Antarctica David G. Long and Mark Drinkwater Brigham Young-378-6586,e-mail: long@ee.byu.edu Abstract-Over large regions of Antarctica, ice sheet and bedrock topography effects in Antarctica. A simple empirical model for the azimuth variation in the radar backscatter

  6. COMPUTER VISION APPLICATIONS TO THE STUDY OF SEA-ICE MOTION IN ANTARCTICA

    E-print Network

    Long, David G.

    COMPUTER VISION APPLICATIONS TO THE STUDY OF SEA-ICE MOTION IN ANTARCTICA Salvador Guti ­ The motion of sea-ice in Antarctica is stud- ied using QuikSCAT scatterometer imagery using meth- ods from covered or in the dark side of the earth, such as Antarctica. Among available data it is worthy to note

  7. 100 Years of Humans in Antarctica1 by Lily Whiteman, National Science Foundation2

    E-print Network

    South Bohemia, University of

    100 Years of Humans in Antarctica1 by Lily Whiteman, National Science Foundation2 3 This winter marks the 100th anniversary of the race to the South Pole. After crossing Antarctica -- the coldest on Anvers Island in the Antarctic Peninsula Region. Forbidding though Antarctica is, the Amundsen

  8. Eocene circulation of the Southern Ocean: Was Antarctica kept warm by subtropical waters?

    E-print Network

    Döös, Kristofer

    Eocene circulation of the Southern Ocean: Was Antarctica kept warm by subtropical waters? Matthew Antarctic warmth. Late Eocene opening of an ocean gateway between Australia and Antarctica was conjectured to have disrupted the EAC, cooled Antarctica, and allowed ice sheets to develop. Here we reconstruct

  9. An extreme precipitation event in Dronning Maud Land, Antarctica: a case study with the Antarctic Mesoscale

    E-print Network

    Schlosser, Elisabeth

    An extreme precipitation event in Dronning Maud Land, Antarctica: a case study with the Antarctic Maud Land, Antarctica, is investigated using Antarctic Mesoscale Prediction System archive data understanding of the frequency of occurrence of intermittent precipitation in the interior of Antarctica in past

  10. Deep-water occurrence of the moss Bryum pseudotriquetrum in Radok Lake, Amery Oasis, East Antarctica

    Microsoft Academic Search

    Bernd Wagner; Rod Seppelt

    2006-01-01

    Mosses form an important component of the flora in terrestrial and lacustrine ecosystems of Antarctica. Here we report the occurrence of mosses in Radok Lake, Amery Oasis, East Antarctica, which has a maximum water depth of c. 360 m and is presumed to be the deepest freshwater lake in Antarctica. Aquatic mosses, determined as Bryum pseudotriquetrum, were found at water depths

  11. Site testing for submillimetre astronomy at Dome C, Antarctica

    NASA Astrophysics Data System (ADS)

    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

    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.

  12. Fabric and texture at Siple Dome, Antarctica

    USGS Publications Warehouse

    Diprinzio, C.L.; Wilen, L.A.; Alley, R.B.; Fitzpatrick, J.J.; Spencer, M.K.; Gow, A.J.

    2005-01-01

    Preferred c-axis orientations are present in the firn at Siple Dome, West Antarctica, and recrystallization begins as shallow as 200 m depth in ice below -20??C, based on digital analysis of c-axis fabrics, grain-sizes and other characteristics of 52 vertical thin sections prepared in the field from the kilometer-long Siple Dome ice core. The shallowest section analyzed, from 22 m, shows clustering of c axes toward the vertical. By 200 m depth, girdle fabric and other features of recrystallized ice are evident in layers (or regions), separated by layers (regions) of typically finer-grained ice lacking evidence of recrystallization. Ice from about 700-780 m depth, which was deposited during the last ice age, is especially fine-grained, with strongly vertical c axes, but deeper ice shows much larger crystals and strong evidence of recrystallization. Azimuthal asymmetry of some c-axis fabrics, trends in grain-size, and other indicators reveal additional information on processes and history of ice flow at Siple Dome.

  13. Sedimentary basins in Ross Sea, Antarctica

    SciTech Connect

    Cooper, A.K.; Davey, F.J.

    1986-07-01

    The Ross Sea lies in the Pacific sector of the Antarctic continental margin. Three major sedimentary basins (from east to west, the Eastern, Central, and Victoria Land basins) lie beneath the broad, deep continental shelf of the Ross Sea. These north-south-trending basins occur in the extensionally deformed region between East and West Antarctica. Multichannel seismic reflection (MCS) surveys have been conducted over these basins since 1980 by West German, French, Japanese, and US expeditions. The MCS and previous geophysical surveys have shown that the three basins contain 5-6 km of sedimentary rock, possibly Late Cretaceous and younger. An additional 6-8 km of sedimentary and volcanic rock lies within the deeper parts of the Victoria Land basin. The basins are separated by uplifted and eroded basement ridges covered by thin sedimentary sections. Each basin has distinct characteristics, commonly related to its extensional origin. Petroleum hydrocarbons are unknown from the Ross Sea region, with the possible exception of ethane gas recovered by the Deep Sea Drilling Project. Previous model studies, based on estimated sediment thickness, assumed temperature gradients, and postulated seismostratigraphy, indicate that hydrocarbons could be generated at depths of 3.5-6km within the sedimentary section. However, this hypothesis cannot be verified without further geologic and geophysical data from the Ross Sea region.

  14. Dehydration-induced cross tolerance of Belgica antarctica larvae to cold and heat is facilitated by trehalose accumulation

    E-print Network

    Lee Jr., Richard E.

    Dehydration-induced cross tolerance of Belgica antarctica larvae to cold and heat is facilitated Antarctica Midge Larvae of the Antarctic midge, Belgica antarctica (Diptera: Chironomidae), are frequently that changes in temperature tolerance in B. antarctica are linked to the rate and severity of dehydration

  15. Arctic, Antarctic, and Alpine Research, Vol. 35, No. 2, 2003, pp. 214217 Populations of Antarctic Hairgrass (Deschampsia antarctica)

    E-print Network

    Barrett, C.H.

    Hairgrass (Deschampsia antarctica) Show Low Genetic Diversity Rolf Holderegger,* Ivana Stehlik,à Ronald I, Deschampsia antarctica. Populations of D. antarctica from two widely separated regions of the maritime that new populations of D. antarctica are founded by one or few individuals, which mainly reproduce by self

  16. Cryoconite and Ice-bubble Microbial Ecosystems in Antarctica

    NASA Technical Reports Server (NTRS)

    Hoover, Richard B.; Rose, M. Franklin (Technical Monitor)

    2000-01-01

    During the Antarctica 2000 Expedition samples of rocks and ice bubbles entrained in ice were collected from the blue ice fields near the Moulton Escarpment of the Thiel Mountains (85S, 94W) and the Morris Moraine of the Patriot Hills (80S, 8 1 W) Ellsworth Mountains of Antarctica. Investigation of the microbiota of these cryoconite and ice bubble ecosystems are now being conducted to help refine chemical and morphological biomarkers of potential significance to Astrobiology. The Antarctica 2000 Expedition will be discussed and the preliminary results of the studies of the ice bubble and cryoconite microbial ecosystems discussed. Recent ESEM images of the Antarctic microbiota will be presented a the relevance of ice ecosystems to Astrobiology will be discussed.

  17. Ecological Biogeography of the Terrestrial Nematodes of Victoria Land, Antarctica

    PubMed Central

    Adams, Byron J.; Wall, Diana H.; Virginia, Ross A.; Broos, Emma; Knox, Matthew A.

    2014-01-01

    Abstract The terrestrial ecosystems of Victoria Land, Antarctica are characteristically simple in terms of biological diversity and ecological functioning. Nematodes are the most commonly encountered and abundant metazoans of Victoria Land soils, yet little is known of their diversity and distribution. Herein we present a summary of the geographic distribution, habitats and ecology of the terrestrial nematodes of Victoria Land from published and unpublished sources. All Victoria Land nematodes are endemic to Antarctica, and many are common and widely distributed at landscape scales. However, at smaller spatial scales, populations can have patchy distributions, with the presence or absence of each species strongly influenced by specific habitat requirements. As the frequency of nematode introductions to Antarctica increases, and soil habitats are altered in response to climate change, our current understanding of the environmental parameters associated with the biogeography of Antarctic nematofauna will be crucial to monitoring and possibly mitigating changes to these unique soil ecosystems. PMID:25061360

  18. Biographical Sketch CASEY BROWN

    E-print Network

    Mountziaris, T. J.

    on adaptation to climate change and will involve undergraduate students and K12 students in a 4H program on STEM and Economic Development: The Role of Variability and a Framework for Resilience," Natural Resources Forum 30

  19. Casey Griffith Professor Kachroo

    E-print Network

    Kachroo, Pushkin

    fan through the use of the Arduino microcontroller/unit. Using a six hour per night sleep average, I, the transistor and the Arduino unit. By constructing the fan's circuit first, next incorporating the relay, then adding the transistor and, finally, programming and connecting the Arduino board, I greatly reduced

  20. Quasi-16-day period oscillations observed in middle atmospheric ozone and temperature in Antarctica

    NASA Astrophysics Data System (ADS)

    Demissie, T. D.; Kleinknecht, N. H.; Hibbins, R. E.; Espy, P. J.; Straub, C.

    2013-07-01

    Nightly averaged mesospheric temperature derived from the hydroxyl nightglow at Rothera station (67°34' S, 68°08' W) and nightly midnight measurements of ozone mixing ratio obtained from Troll station (72°01' S, 2°32' E) in Antarctica have been used to investigate the presence and vertical profile of the quasi-16-day planetary wave in the stratosphere and mesosphere during the Antarctic winter of 2009. The variations caused by planetary waves on the ozone mixing ratio and temperature are discussed, and spectral and cross-correlation analyses are performed to extract the wave amplitudes and to examine the vertical structure of the wave from 34 to 80 km. The results show that while planetary-wave signatures with periods 3-12 days are strong below the stratopause, the oscillations associated with the 16-day wave are the strongest and present in both the mesosphere and stratosphere. The period of the wave is found to increase below 42 km due to the Doppler shifting by the strong eastward zonal wind. The 16-day oscillation in the temperature is found to be correlated and phase coherent with the corresponding oscillation observed in O3 volume mixing ratio at all levels, and the wave is found to have vertical phase fronts consistent with a normal mode structure.

  1. Mapping the extent and relative toxicity of sediments, Winter Quarters Bay, Antarctica

    SciTech Connect

    Crockett, A.; White, G. [Idaho National Engineering Lab., Idaho Falls, ID (United States); Huynh, H. [Microbics Corp., Carlsbad, CA (United States)

    1995-12-31

    McMurdo Station was established in the mid 1950s and is the largest research station in Antarctica. In earlier days, wastes were dumped on the steep shores of Winter Quarters Bay, dosed with up to 19,000 L of diesel or jet fuel and ignited. Along with periodic fuel spills, and the discharge of raw sewage the Bay became littered with trash and contaminated with elevated levels of metals, PCBs and petroleum hydrocarbons. The original benthic community was essentially totally replaced with more opportunistic species. In 1993, a study was initiated to map the distribution of PCB and hydrocarbon contamination as well as determine sediment pore water toxicity. Sediments were collected from over forty locations with an Ekman dredge after drilling through about 210 cm of ice. Maps of sediment particle size distribution, percent organic carbon, total PCBs, total petroleum hydrocarbons, etc. were developed. Potential toxicity was mapped by normalizing the data to 1 percent organic carbon and comparing the data with various sediment quality criteria. While onsite sediment pore water toxicity tests showed essentially no impacts, the new Microtox{trademark} chronic bioassay on both pore water and solvent extra showed considerable toxic effects. This paper compares the relative levels of contamination, with sediment quality criteria and toxicity as determined by a chronic microbial bioassays.

  2. Ambient Seismic Noise Correlation on Iceberg C16, Ross Sea, Antarctica

    NASA Astrophysics Data System (ADS)

    Wang, Y.; Okal, E. A.; MacAyeal, D. R.

    2014-12-01

    This study focuses on the ambient noise transmission between 4 seismometer stations distributed on iceberg C16, Ross Sea, Antarctica. These stations were deployed for a 60-day period in 2003/4. The noise source was associated with constant collisions between C16 and a neighboring iceberg, B15A, which was continually being driven into the northeast edge of C16 by ocean tides. The most significant modes of ambient noise transmission were found to be (1) hydroacoustic modes that bounce off the seabed below the iceberg, and (2) flexural-gravity waves that involve the flexural rigidity of the ice layer. The technique used in the study (and in similar studies of the Amery Ice Shelf reported by Zhan and others) provides a new method for studying floating ice with high sensitivity to factors that control hydroacoustic propagation over long distances. It is possible that secular changes in the sub ice ocean layer (such as changes caused by decreasing ice thickness over time) can be observed using ambient noise correlation similar to that performed here. This suggests a way in which seismic observations can constrain variables that characterize how floating ice, and in particular floating ice shelves, buttress glaciers and ice streams that discharge into the ocean.

  3. Nutrient exchange in an Antarctic macrolichen during summer snowfall snow melt events

    Microsoft Academic Search

    P. D. Crittenden

    1998-01-01

    Concentrations of NH4+, NO3-, PO43-, K+, Ca2+ and Mg2+ in snow meltwater resulting from summer snow showers were monitored before and after its passage through monospecific stands of the Antarctic macrolichen Usnea sphacelata R. Br. The sampling was conducted under field conditions near Casey Station in East Antarctica between January and March. Total snow deposition during the 61-d period was

  4. Study of long path VLF signal propagation characteristics as observed from Indian Antarctic station, Maitri

    NASA Astrophysics Data System (ADS)

    Sasmal, Sudipta; Pal, Sujay; Chakrabarti, Sandip K.

    2014-10-01

    To examine the quality and propagation characteristics of the Very Low Frequency (VLF) radio waves in a very long propagation path, Indian Centre for Space Physics, Kolkata, participated in the 27th Indian scientific expedition to Antarctica during 2007-2008. One Stanford University made AWESOME VLF receiving system was installed at the Indian Antarctic station Maitri and about five weeks of data were recorded successfully from the Indian transmitter VTX and several other transmitting stations worldwide. The quality of the signal from the VTX transmitter was found to be very good, consistent and highly stable in day and night. The signal shows the evidences of the presence of the 24 h solar radiation in the Antarctic region during local summer. Here we report the both narrow band and broadband VLF observations from this site. The diurnal variations of VTX signal (18.2 kHz) are presented systematically for Antarctica path and also compared the same with the variations for a short propagation path (VTX-Kolkata). We compute the spatial distribution of the VTX signal along the VTX-Antarctica path using the most well-known LWPC model for an all-day and all-night propagation conditions. The calculated signal amplitudes corresponding to those conditions relatively corroborate the observations. We also present the attenuation rate of the dominant waveguide modes corresponding to those propagation conditions where the effects of the Antarctic polar ice on the attenuation of different propagating waveguide modes are visible.

  5. A re-consideration of the taxonomic status of Nebria lacustris Casey (Coleoptera, Carabidae, Nebriini) based on multiple datasets – a single species or a species complex?

    PubMed Central

    Kavanaugh, David H.; Archambeault, Sophie L.; Roopnarine, Peter D.; Ledford, Joel

    2011-01-01

    Abstract This study gathered evidence from principal component analysis (PCA) of morphometric data and molecular analyses of nucleotide sequence data for four nuclear genes (28S, TpI, CAD1, and Wg) and two mitochondrial genes (COI and 16S), using parsimony, maximum likelihood, and Bayesian methods. This evidence was combined with morphological and chorological data to re-evaluate the taxonomic status of Nebria lacustris Casey sensu lato. PCA demonstrated that both body size and one conspicuous aspect of pronotal shape vary simultaneously with elevation, latitude, and longitude and served to distinguish populations from the southern Appalachian highlands, south of the French Broad, from all other populations. Molecular analyses revealed surprisingly low overall genetic diversity within Nebria lacustris sensu lato, with only 0.39% of 4605 bp varied in the concatenated dataset. Evaluation of patterns observed in morphological and genetic variation and distribution led to the following taxonomic conclusions: (1) Nebria lacustris Casey and Nebria bellorum Kavanaugh should be considered distinct species, which is a NEW STATUS for Nebria bellorum. (2) No other distinct taxonomic subunits could be distinguished with the evidence at hand, but samples from northeastern Iowa, in part of the region known as the “Driftless Zone”, have unique genetic markers for two genes that hint at descent from a local population surviving at least the last glacial advance. (3) No morphometric or molecular evidence supports taxonomic distinction between lowland populations on the shores of Lake Champlain and upland populations in the adjacent Green Mountains of Vermont, despite evident size and pronotal shape differences between many of their members. PMID:22379387

  6. Ecophysiology of soil bacteria in the vicinity of Henryk Arctowski Station, King George Island, Antarctica

    Microsoft Academic Search

    Marek K. Zdanowski; Piotr W?gle?ski

    2001-01-01

    Microbial abundance and diversity in soil samples from a ca. 0.2km2 area in Admiralty Bay, King George Island, were analysed by epifluorescence microscopy and plate counts. Total bacterial counts (TC) varied little compared to the elemental content of the organic matter (c.v.TC 51% vs. c.v.C,N,S 131, 171 and 204%, respectively). The number of copiotrophic colony forming bacteria (CFU) fluctuated widely

  7. FY 1993 environmental sampling and analysis report for wastewater discharge at McMurdo Station, Antarctica

    SciTech Connect

    Crockett, A.B.

    1994-04-01

    Wastewater impact assessment at McMurdo has been or is being conducted by four organizations: Antarctic Support Associates (ASA), which conducts the effluent monitoring; Moss Landing Marine Laboratories, which conducts all of the benthic monitoring and most of the biological monitoring; Montana State University, which conducted water quality and water current measurements; and EG&G Idaho, which conducted water quality and sea ice monitoring. All four programs are interrelated and were needed to determine the impact of the wastewater discharge on the marine environment. This report summarizes the relevant monitoring work being conducted by Antarctic Support Associates, Moss Landing, and Montana State personnel, and specifically documents the results of EG&G Idaho`s efforts.

  8. Avian cholera in Southern Great Petrel (Macronectes giganteus) from Antarctica

    USGS Publications Warehouse

    Leotta, G.A.; Rivas, M.; Chinen, I.; Vigo, G.B.; Moredo, F.A.; Coria, N.; Wolcott, M.J.

    2003-01-01

    A southern giant petrel (Macronectes giganteus) was found dead at Potter Peninsula, King George Island, South Shetland, Antarctica. The adult male was discovered approximately 48 hr after death. Macroscopic and microscopic lesions were compatible with avian cholera and the bacterium Pasteurella multocida subsp. gallicida, serotype A1 was isolated from lung, heart, liver, pericardial sac, and air sacs. In addition, Escherichia coli was isolated from pericardial sac and air sacs. This is the first known report of avian cholera in a southern giant petrel in Antarctica.

  9. Climate change during the last deglaciation in Antarctica

    SciTech Connect

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

    1996-06-14

    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.

  10. Declassified Intelligence Satellite Photography (DISP) Coverage of Antarctica

    NASA Technical Reports Server (NTRS)

    Bindschadler, Robert; Seider, Wendy

    1998-01-01

    This report summarizes the results of a nine-week summer project examining all Declassified Intelligence Satellite Photography (DISP) of Antarctica. It was discovered that the data were collected in three separate missions during 1962 and 1963. The first two missions covered only the coastal areas, while the third mission covered the entire continent. Many of the 1782 frames collected were cloudy. This is especially true of West Antarctica. An optimal set of photographs covering the entire Antarctic coastline is identified along with some examples that show changes in the coastline which have occurred since the early 1960s.

  11. Comprehensive Study of the Crust and Upper Mantle within East and West Antarctica Based on S-wave Receiver Functions

    NASA Astrophysics Data System (ADS)

    Ramirez, C.; Nyblade, A.; O'Donnell, J.; Hansen, S. E.; Wiens, D. A.; Anandakrishnan, S.; Aster, R. C.; Huerta, A. D.; Shore, P.; Wilson, T. J.

    2013-12-01

    In regions with thick ice cover, reverberations within the ice layer create multiples that can be observed in P-wave receiver functions. The P-to-S (Ps) conversion from the crust-mantle boundary is often masked by the ice multiples. S-wave receiver functions (SRF) are an alternate way to estimate the crustal structure using the S-to-P (Sp) conversions, which do not interfere with the ice multiples. We analyzed broadband data from the AGAP and POLENET temporary networks encompassing 46 stations. Moho Sp arrivals are clearly seen at ~6-8 sec for the AGAP stations and at ~3-4 sec for the POLENET stations. The SRF's were migrated to depth using the 1D ak135 global velocity model. Stations for the TAMSEIS network are currently being examined. A grid search approach was used to obtain Moho depths constrained by both receiver functions and Rayleigh wave phase and group velocities on all three of the networks. A comprehensive study for East and West Antarctica will be presented using consistent methodology within all three of the networks, enabling direct comparisons among the three regions.

  12. Seasonal and inter-annual mass variability in Antarctica from GRACE

    NASA Astrophysics Data System (ADS)

    Pangaluru, K.; Velicogna, I.; Swenson, S. C.; van den Broeke, M. R.; Bromwich, D. H.; Monaghan, A. J.

    2011-12-01

    The seasonal and inter-annual variability in Antarctic surface mass balance represent important components of the temporal variability in total ice sheet mass balance. At present, large uncertainties remain in our knowledge of those temporal components, spatial distribution and long-term trend. GRACE measurements of time variable gravity represent one of the only ways to directly measure the monthly ice sheet mass changes and - if accurate enough - provide important insights to constrain the seasonal and inter-annual variability in surface mass balance, which in turn is essential to evaluate global and regional atmospheric climate model outputs. In Antarctica, errors in the atmospheric mass correction applied to the GRACE data are the dominant uncertainties on the retrieval of seasonal and inter-annual mass changes. We estimate the error in monthly GRACE correction for the atmospheric mass distribution by comparing surface pressure fields from available GPS-RO (e.g. CHAMP, SAC-C, and COSMIC) and ECMWF pressure fields. We evaluate the results using available surface pressure measurements from Automatic Weather Stations (AWS). We compare the spatial pattern in our atmospheric error estimates with different estimates of surface mass balance (SMB) derived from regional atmospheric climate model outputs, from the continental scale down to the regional scale, to determine if those errors are associated to particular regional conditions and climatic regimes. We show that when averaged over the entire ice sheet or East or West Antarctica, the accuracy of the GRACE data is sufficient to constrain seasonal and inter-annual changes in surface mass balance. But when moving to smaller scales, e.g. at the scale of a drainage basin, we identify regions where the uncertainty in atmospheric mass correction is large enough to impair the scientific interpretability of the GRACE results. In those areas, we generate preliminary corrections to the GRACE data and evaluate the results.

  13. Sources and elemental composition of summer aerosols in the Larsemann Hills (Antarctica).

    PubMed

    Budhavant, Krishnakant; Safai, P D; Rao, P S P

    2015-02-01

    Atmospheric aerosols play a major role in the global climate change. A better physical characterization of the chemical composition of atmospheric aerosols, especially in remote atmosphere, is an important step to reduce the current uncertainty in their effect on the radiative forcing of the climate. In the present work, surface aerosols have been studied over the Southern Ocean and over Bharati, Indian Research Station at Larsemann Hills at the Antarctic coast during the summer season of 2009-2010. Aerosol samples were collected using optical particle counter (OPC) and high-volume air sampler. PM10 and PM2.5 aerosol samples were analyzed for various water-soluble and acid-soluble ionic constituents. The Hysplit model was used to compute the history of the air masses for their possible origin. Supplementary measurements of meteorological parameters were also used. The average mass concentration for PM10 over the Southern Ocean was found to be 13.4 ?g m(3). Over coastal Antarctica, the mass of PM10 was 5.13 ?g m(-3), whereas that of PM2.5 was 4.3 ?g m(-3). Contribution of marine components, i.e., Na, Cl and Mg was dominant over the Southern Ocean (79 %) than over the coastal Antarctica where they were dominant in coarse mode (67 %) than in fine mode (53 %) aerosols. The NH4/nss-SO4 ratio of 1.12 in PM2.5 indicates that the NH4 and SO4 ions were in the form of NH4HSO4. Computation of enrichment factors indicate that elements of anthropogenic origin, e.g., Zn, Cu, Pb, etc., were highly enriched with respect to crustal composition. PMID:25167815

  14. Real-time tele-echocardiography: diagnosis and management of a pericardial effusion secondary to pericarditis at an Antarctic research station.

    PubMed

    Otto, Christian A; Shemenski, Ronald; Drudi, Laura

    2012-09-01

    The McMurdo Research Station medical facility functions at the level of a rural community hospital emergency department. Telehealth technology has played an increasingly important role in providing intercontinental tertiary healthcare consultations, particularly for assistance with diagnostically challenging cases or cases involving complicated medical management. The role of telehealth in Antarctica is vital given the harsh and remote environment. The following case discusses a real-time tele-ultrasound consultation between the station physician and a patient with pericarditis at the McMurdo Medical Clinic in Antarctica and a team of cardiology consultants at the University of Texas Medical Branch, Galveston, TX. The use of teleheath technologies prevented an unnecessary intercontinental medical evacuation and allowed the patient to receive treatment at the McMurdo Research Station. This case report demonstrates that real-time tele-ultrasound can serve as an important diagnostic resource in the delivery of healthcare to isolated populations in remote environments. PMID:22822790

  15. Space station power system

    NASA Technical Reports Server (NTRS)

    Baraona, Cosmo R.

    1987-01-01

    The major requirements and guidelines that affect the space station configuration and power system are explained. The evolution of the space station power system from the NASA program development-feasibility phase through the current preliminary design phase is described. Several early station concepts are described and linked to the present concept. Trade study selections of photovoltaic system technologies are described in detail. A summary of present solar dynamic and power management and distribution systems is also given.

  16. Inflatable Station Concept

    NASA Technical Reports Server (NTRS)

    1961-01-01

    Unlike many other early space station concepts, this design actually made it out of the concept phase and into production, though no models were ever flown. This particular station was 30-feet and expandable. It was designed to be taken to outer space in a small package and then inflate in orbit. The station could, in theory, have been big enough for 1 to 2 people to use for a long period of time. A similar 24 foot station was built by the Goodyear Aircraft Corporation for NASA test use. The concept of space inflatables was revived in the 1990s.

  17. Spatial-temporal dynamics of chemical composition of surface snow in East Antarctic along the transect Station Progress-Station Vostok

    NASA Astrophysics Data System (ADS)

    Khodzher, T. V.; Golobokova, L. P.; Shibaev, Y. A.; Lipenkov, V. Y.; Petit, J. R.

    2013-05-01

    This paper presents data on chemical composition of the Antarctic snow sampled during the 53rd Russian Antarctic Expedition (RAE, 2008) along the first tractor traverse (TT) from Station Progress to Station Vostok (East Antarctica). Snow samples were obtained from the cores drilled at 55.3, 253, 337, 369, 403, 441, 480, 519, 560, 618, 819, and 1276 km from Station Progress. Data on horizontal and deep distribution of chemical components in the snow provide evidence of spatial and temporal variations of conditions for the snow cover formation along the transect under study. Sea salt was the main source for chemical composition of snow cover near the ice edge. Concentrations of marine-derived components decreased further inland. A hypothesis was put forward that some ions in the snow cover of the central part of East Antarctica were likely to be of continental origin. Elevated concentrations of sulphate ions of continental origin were recorded in some profiles of the transect at a depth of 130-150 cm which was attributed to buried signals of the Pinatubo volcano eruption (1991).

  18. Parts of Antarctica's King George Island are littered with trash

    NASA Astrophysics Data System (ADS)

    Kumar, Mohi

    2013-02-01

    A report released 7 February by ecologists from Germany's Friedrich Schiller University Jena reveals that parts of King George Island, a logistical hub for international research in Antarctica, are home to open pits of trash, decaying field huts, and other forms of pollution.

  19. Fossil and Recent Cheilostomata (Bryozoa) from the Ross Sea, Antarctica

    Microsoft Academic Search

    P. J. Hayward; P. D. Taylor

    1984-01-01

    Fifty-six species of cheilostome Bryozoa have been identified in samples from the McMurdo Sound area of the Ross Sea, Antarctica. Material collected alive from beneath the permanent ice sheet, at White Island and Cape Bird, is supplemented by fossil material collected from a coastal moraine deposit at Black Island. The moraine is thought to have formed through the ablation of

  20. ACCUMULATION RATE MEASUREMENTS AT TAYLOR DOME, EAST ANTARCTICA

    E-print Network

    Marshall, Hans-Peter

    , TOMAS A. NEUMANN1, ERIC J. STEIG3'4,JACK E. DIBB5, DALE P. WINEBRENNER6 and ROBERT J. ARTHERN6., Neumann,T.A., Steig, E.J., Dibb, J.E., Winebrenner,D.P. andArthern R.J., 1999ACCUMULATION RATE MEASUREMENTS AT TAYLOR DOME, EAST ANTARCTICA: TECHNIQUES AND STRATEGIES FOR MASS

  1. Antarctica: Arena for South American Cooperation or Conflict.

    ERIC Educational Resources Information Center

    Child, Jack

    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.…

  2. Temperature variability beneath Ronne Ice Shelf, Antarctica, from thermistor cables

    Microsoft Academic Search

    Keith W. Nicholls

    1996-01-01

    Thermistor cables have been deployed at two sites beneath Ronne Ice Shelf, Antarctica. One site is to the east of a submarine ridge that delineates the eastern boundary of the Ronne Depression, and the other is 100 km to the north, above the eastern slope of the depression. Long records from the cables (up to 22 months) indicate a large

  3. Fossil hydrothermal systems tracking Eocene climate change in Antarctica

    Microsoft Academic Search

    Luigi Dallai; Claudio Ghezzo; Antonio Longinelli

    2001-01-01

    During the Cenozoic, alkaline magmatism related to rifting in the Ross Sea embayment affected the basement of northern Victoria Land, Antarctica. Shallow intrusions supplied the necessary heat to cause groundwater circulation through permeable rocks, producing local hydrothermal systems. In the granitoid country rocks of the two adjacent areas of Mt. Monteagle and Mt. McGee, the biotite deltaD values range from

  4. Proteolytic anaerobic bacteria from lake sediments of Antarctica

    Microsoft Academic Search

    Smita Dube; Lokendra Singh; S. I Alam

    2001-01-01

    Amongst twenty five proteolytic bacteria isolated from lake sediment samples of Antarctica, six isolates were selected based on SDS PAGE protein profile and zone of hydrolysis on casein agar at 10°C. Most of the cultures were rod shaped and motile with two showing terminal bulging spores. Isolates grew between 5°C to 37°C and protease was induced in the late log,

  5. Photophysiological acclimation of Phaeocystis antarctica Karsten under light limitation

    Microsoft Academic Search

    Tiffany A. Moisan; B. Greg Mitchell

    1999-01-01

    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

  6. An integrative study of a meromictic lake ecosystem in Antarctica

    Microsoft Academic Search

    Federico M Lauro; Matthew Z DeMaere; Sheree Yau; Mark V Brown; Charmaine Ng; David Wilkins; Mark J Raftery; John AE Gibson; Cynthia Andrews-Pfannkoch; Matthew Lewis; Jeffrey M Hoffman; Torsten Thomas; Ricardo Cavicchioli

    2011-01-01

    In nature, the complexity and structure of microbial communities varies widely, ranging from a few species to thousands of species, and from highly structured to highly unstructured communities. Here, we describe the identity and functional capacity of microbial populations within distinct layers of a pristine, marine-derived, meromictic (stratified) lake (Ace Lake) in Antarctica. Nine million open reading frames were analyzed,

  7. Cold tolerance in Tardigrada from Dronning Maud Land, Antarctica

    Microsoft Academic Search

    Lauritz Sømme; Terje Meier

    1995-01-01

    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

  8. Geological Structure of Mac. Robertson Land (East Antarctica)

    NASA Astrophysics Data System (ADS)

    Grew, Edward S.

    In East Antarctica, bedrock emerges from under the continental ice sheet in coastal hills and skerries or in mountain ranges within 200 km of the coast. However, the ice sheet in Mac. Robertson Land has been lowered by the Lambert Glacier to such an extent that mountain ranges up to 600 km inland are exposed. These bedrock exposures are the only direct access geologists have to the interior of East Antarctica. While the predominance of granulite facies rocks in the coastal areas give the impression that most of East Antarctica is underlain by such high-grade rocks, the presence of low-grade rocks in southern Mac. Robertson Land indicates that the interior of East Antarctica is probably a far more diverse terrain. The present book is one view of this interior: It summarizes the results that Soviet geoscientists obtained from field operations between 1966 and 1974 in Mac. Robertson Land. The territory covered by this study includes a coastal belt of granulite facies rocks and charnockites and the interior area (southern Prince Charles Mountains) of gneissic granites and metasediments and metavolcanics with greenschist to amphibolite facies. Soviet contributions to our present geological knowledge of these areas have been substantial, most notably the discovery of a banded iron formation at Mount Ruker in the southern Prince Charles Mountains. Moreover, the Soviets were the first to recognize the significance of the continental rift presently occupied by the Lambert Glacier and Amery Ice Shelf, and they have documented this rift by geophysical and geological observations.

  9. Polar stratospheric clouds over Antarctica from the CALIPSO spaceborne lidar

    Microsoft Academic Search

    Vincent Noel; Albert Hertzog; Hélène Chepfer; David M. Winker

    2008-01-01

    This paper presents statistics of polar stratospheric clouds (PSCs) above Antarctica from June to October 2006 using observations from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) spaceborne lidar, part of the CALIPSO mission. Synoptic-scale changes in geographic and temporal distribution are documented weekly and correlated with temperature fields. A high spatial and temporal variability tends to contradict the hypothesis that

  10. Anaerobic psychrophiles from Lake Zub and Lake Untersee, Antarctica

    Microsoft Academic Search

    Alisa Townsend; Elena V. Pikuta; Melissa Guisler; Sarah Stahl; Richard B. Hoover

    2009-01-01

    The study of samples from Antarctica 2008 and 2009 expeditions organized and successfully conducted by Richard Hoover led to the isolation of diverse anaerobic strains with psychrotolerant and psychrophilic physiology. Due to the fact that Lake Untersee has never been subject to microbiological study, this work with the samples has significant and pioneering impact to the knowledge about the biology

  11. Radar-based subglacial lake classification in Antarctica

    Microsoft Academic Search

    Sasha P. Carter; Donald D. Blankenship; Matthew E. Peters; Duncan A. Young; John W. Holt; David L. Morse

    2007-01-01

    Subglacial lakes in East Antarctica can be separated into four categories specified by radar reflection properties. Definite lakes are brighter than their surroundings by at least 2 dB (relatively bright) and both are consistently reflective (specular) and have a reflection coefficient greater than ?10 dB (absolutely bright). Dim lakes are relatively bright and specular but not absolutely bright, indicating nonsteady

  12. Antarctica as a launch-pad for space astronomy missions

    Microsoft Academic Search

    J. W. V. Store; M. C. B. Ashley

    2002-01-01

    In the coming decades, astronomical breakthroughs will increasingly come from observations from the best ground- based locations and from space observatories. At infrared and sub-millimetre wavelengths in particular, Antarctica offers site conditions that are found nowhere else on earth. There are two implications of this. First, for tackling some of the most crucial problems in astrophysics, a large telescope in

  13. Triassic Leech Cocoon From Antarctica Contains Fossil Bell Animal

    E-print Network

    Bomfleur, Benjamin; Kerp, Hans; Taylor, Thomas N.; Moestrup, Ø jvind; Taylor, Edith L.

    2012-01-01

    that is encased inside the wall layer of a more than 200 Ma leech cocoon from Antarctica. The microfossil consists of a helically contractile stalk that attaches to a main body with a peristomial feeding apparatus and a large Cshaped macronucleus. It agrees...

  14. Surface temperature and salinity variations between Tasmania and Antarctica, 19931999

    E-print Network

    the temperature data. The Levitus climatological and Reynolds satellite monthly mean sea surface temperature dataSurface temperature and salinity variations between Tasmania and Antarctica, 1993­1999 Alexis 2002. [1] Continuous surface temperature and salinity measurements have been collected onboard a supply

  15. Separating metamorphic events in the Fosdick migmatitegranite complex, West Antarctica

    E-print Network

    Baxter, Ethan F.

    ). However, constraining the timing of these events is difficult because the geological signifi- canceSeparating metamorphic events in the Fosdick migmatite­granite complex, West Antarctica F. J of Applied Geology, Curtin University, GPO Box U1987, Perth WA 6845, Australia (f.korhonen@curtin.edu.au) 2

  16. Desiccation tolerance of three moss species from continental Antarctica

    Microsoft Academic Search

    Sharon A. Robinson; J. Wasley; M. Popp; C. E. Lovelock

    2000-01-01

    Tolerance of desiccation was examined in three species of moss, Grimmia antarctici Card., Ceratodon purpureus (Hedw.) Brid. and Bryum pseudotriquetrum (Hedw.) Gaertn., Meyer et Scherb. collected from two sites of contrasting water availability in the Windmill Islands, continental Antarctica. Physiological tolerance to desiccation was measured using chlorophyll fluorescence in plugs of moss during natural drying in the laboratory. Differences in

  17. Space station executive summary

    NASA Technical Reports Server (NTRS)

    1972-01-01

    An executive summary of the modular space station study is presented. The subjects discussed are: (1) design characteristics, (2) experiment program, (3) operations, (4) program description, and (5) research implications. The modular space station is considered a candidate payload for the low cost shuttle transportation system.

  18. "Inventive" Learning Stations

    ERIC Educational Resources Information Center

    Jarrett, Olga

    2010-01-01

    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…

  19. Correlation between mesospheric ozone and Energetic Particle Precipitation over Troll, Antarctica in the years 2008 and 2009

    NASA Astrophysics Data System (ADS)

    Daae, M.; Espy, P. J.; Nesse Tyssøy, H.; Newnham, D. A.

    2013-12-01

    The British Antarctic Survey radiometer stationed at Troll, Antarctica (72S, 2.5E, L=4.76) measured ozone in the lower mesosphere and upper stratosphere from February 2008 until February 2010. By looking at anomalies in the polar-winter nighttime ozone, we are able to quantify the influence of Energetic Particle Precipitation (EPP) on ozone during these two years. Time-lagged correlations between geomagnetic indices (AE, Kp and Dst) and ozone anomalies as a function of height have been calculated to quantify which of the indices best accounts for the variability in the ozone. In addition, the MEPED instruments aboard the NOAA satellites have been used to quantify the EPP flux precipitating over Troll. Since the solar activity in 2008 undergoes a strong periodicity, which is linked to rotating coronal holes, this periodicity is also manifested in the EPP and the geomagnetic indices. A correlation analysis between the ozone over Troll and the periodic solar activity that is reflected in the EPP is also carried out, resulting in a statistical quantification of the EPP effects on mesospheric ozone as measured over Troll, Antarctica.

  20. Baseline values for metals in soils on Fildes Peninsula, King George Island, Antarctica: the extent of anthropogenic pollution.

    PubMed

    Lu, Zhibo; Cai, Minghong; Wang, Juan; Yang, Haizhen; He, Jianfeng

    2012-11-01

    Metal contents (Al, Ca, Cd, Cr, Cu, Fe, Hg, Mg, Mn, Ni, Pb, Ti, and Zn) have been measured in 30 surface soils on Fildes Peninsula, King George Island, Antarctica, yielding values (in milligrams kilogram(-1)) of 41.57-80.65 (Zn), 2.76-60.52 (Pb), 0.04-0.34 (Cd), 7.18-25.03 (Ni), 43,255-70,534 (Fe), 449-1,401 (Mn), 17.10-64.90 (Cr), 1,440-25,684 (Mg), 10,941-49,354 (Ca), 51.10-176.50 (Cu), 4,388-12,707 (Ti), 28,038-83,849 (Al), and for Hg (in nanograms gram(-1)) 0.01-0.06. Relative cumulative frequency analysis was used to determine the baseline values for the 13 metals. Compared with adjacent areas in Antarctica, Mg and Ni are significantly lower, but Cu is significantly higher than that of McMurdo Station. Enrichment factor analysis and the geo-accumulation index method were applied in order to determine the extent of anthropogenic contamination, and both show that Pb, Cd, and Hg have been significantly increased by human activities. Principal component analysis was used to identify the sources of metals in these soil samples. PMID:22160386

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

    NASA Astrophysics Data System (ADS)

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

    2010-05-01

    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.

  2. Circular surface depression on Roi Baudoin Ice Shelf, Dronning Maud Land, East Antarctica - characteristics and possible origin

    NASA Astrophysics Data System (ADS)

    Helm, Veit; Eagles, Graeme; Müller, Christian; Binder, Tobias; Käßbohrer, Johannes; Drews, Reinhard; Lenaerts, Jan; Steinhage, Daniel; Eisen, Olaf

    2015-04-01

    We present airborne geophysical data of a ring structure observed in the 2014/15 field season on Roi Baudoin Ice Shelf, East Antarctica. Different processes regarding the origin of this structure were already discussed in the media. The feature resembles well-known dolines frequently observed on Antarctic Peninsula ice shelves, but also looks like a reminiscent from subglacial lake drainage as recently observed in several locations in Greenland. Several equally sized and smaller features can be observed in the vicinity. Currently, the feature is located on the ice shelf and advects with ice flow. Using our observations and records of a nearby weather station we discuss whether it was formed on the ice shelf itself or upstream of the grounding line where ice was grounded, and whether processes underneath the ice (e.g. subglacial lakes or ice-shelf basal melt), processes at the surface (like ponding melt water), or other processes could responsible for its origin.

  3. The space station

    NASA Technical Reports Server (NTRS)

    Munoz, Abraham

    1988-01-01

    Conceived since the beginning of time, living in space is no longer a dream but rather a very near reality. The concept of a Space Station is not a new one, but a redefined one. Many investigations on the kinds of experiments and work assignments the Space Station will need to accommodate have been completed, but NASA specialists are constantly talking with potential users of the Station to learn more about the work they, the users, want to do in space. Present configurations are examined along with possible new ones.

  4. Space station propulsion technology

    NASA Technical Reports Server (NTRS)

    Norman, A. M.; Briley, G. L.; Evans, S. A.

    1987-01-01

    The objectives of this program are to provide a demonstration of hydrogen/oxygen propulsion technology readiness for the initial operational capability (IOC) space station application, specifically gaseous hydrogen/oxygen and warm hydrogen thruster concepts, and to establish a means for evolving from the IOC space station propulsion system (SSPS) to that required to support and interface with advanced station functions. These objectives were met by analytical studies and by furnishing a propulsion test bed to the Marshall Space Flight Center for testing.

  5. Space Station Induced Monitoring

    NASA Technical Reports Server (NTRS)

    Spann, James F. (editor); Torr, Marsha R. (editor)

    1988-01-01

    This report contains the results of a conference convened May 10-11, 1988, to review plans for monitoring the Space Station induced environment, to recommend primary components of an induced environment monitoring package, and to make recommendations pertaining to suggested modifications of the Space Station External Contamination Control Requirements Document JSC 30426. The contents of this report are divided as Follows: Monitoring Induced Environment - Space Station Work Packages Requirements, Neutral Environment, Photon Emission Environment, Particulate Environment, Surface Deposition/Contamination; and Contamination Control Requirements.

  6. Space Station - early

    NASA Technical Reports Server (NTRS)

    1961-01-01

    Manned Space Laboratory Research. James Hansen wrote: 'Langley built and tested various models of the Erectable Torus Manned Space Laboratory, including a full-scale research model constructed by Goodyear.' The uninflated station was packed around a 24-foot diameter torus and could be launched inside a rocket. 'The first idea for an inflatable station was the Erectable Torus Manned Space Laboratory. A Langley space station team led by Paul Hill and Emanuel 'Manny' Schnitzer developed the concept with the help of the Goodyear Aircraft Corporation.'

  7. The bipolar diatoms Thalassiosira antarctica Comber and Porosira glacialis (Grun) J2rg.: morphology and autecology of disjunct populations

    E-print Network

    Villareal, Tracy Alan

    1981-01-01

    clone resting spore valve view 35 35 19. T. antarctica var. borealis ? whole cell 20. var. borealis bands, 4oC 21a. var. borealis internal view 21b. Central strutted process group 22. External tubes, -1. 5 C 37 37 37 37 LIST OF FIGURES (cont.... ) FIGURE 23. var. borealis bands, -1. 5oC PAGE 37 24. Thalassiosira antarctica var. antarctica valve view, 4oC 39 25. var. antarctica bands, -1. 5 C 26a. Field sample of var. antarctica, -1. 2 C 26b. var. antarctica field sample bands 27. var...

  8. Diversity of bacteria producing pigmented colonies in aerosol, snow and soil samples from remote glacial areas (Antarctica, Alps and Andes)

    NASA Astrophysics Data System (ADS)

    González-Toril, E.; Amils, R.; Delmas, R. J.; Petit, J.-R.; Komárek, J.; Elster, J.

    2008-04-01

    Four different communities and one culture of pigmented microbial assemblages were obtained by incubation in mineral medium of samples collected from high elevation snow in the Alps (Mt. Blanc area) and the Andes (Nevado Illimani summit, Bolivia), from Antarctic aerosol (French station Dumont d'Urville) and a maritime Antarctic soil (King George Island, South Shetlands, Uruguay Station Artigas). Molecular analysis of more than 200 16S rRNA gene sequences showed that all cultured cells belong to the Bacteria domain. The phylogenetic comparison with the currently available rDNA database allowed the identification of sequences belonging to Proteobacteria (Alpha-, Beta- and Gamma-proteobacteria), Actinobacteria and Bacteroidetes phyla. The Andes snow culture was the richest in bacterial diversity (eight microorganisms identified) and the maritime Antarctic soil the poorest (only one). Snow samples from Col du midi (Alps) and the Andes shared the highest number of identified microorganisms (Agrobacterium, Limnobacter, Aquiflexus and two uncultured Alphaproteobacteria clones). These two sampling sites also shared four sequences with the Antarctic aerosol sample (Limnobacter, Pseudonocardia and an uncultured Alphaproteobacteria clone). The only microorganism identified in the maritime Antarctica soil (Brevundimonas sp.) was also detected in the Antarctic aerosol. The two snow samples from the Alps only shared one common microorganism. Most of the identified microorganisms have been detected previously in cold environments (Dietzia kujamenisi, Pseudonocardia Antarctica, Hydrogenophaga palleronii and Brebundimonas sp.), marine sediments (Aquiflexus balticus, Pseudomonas pseudoalkaligenes, Pseudomonas sp. and one uncultured Alphaproteobacteria), and soils and rocks (Pseudonocardia sp., Agrobactrium sp., Limnobacter sp. and two uncultured Alphaproteobacetria clones). Air current dispersal is the best model to explain the presence of very specific microorganisms, like those used in this work, in very distant environments. In addition these microorganisms have to be resistant to extreme conditions and able to grow in oligotrophic environments. Considering the habitats in which they have been identified, the presence of pigments must be related with their ability to resist high doses of radiation.

  9. Enabler operator station

    NASA Astrophysics Data System (ADS)

    Bailey, Andrea; Keitzman, John; King, Shirlyn; Stover, Rae; Wegner, Torsten

    The objective of this project was to design an onboard operator station for the conceptual Lunar Work Vehicle (LWV). This LWV would be used in the colonization of a lunar outpost. The details that follow, however, are for an earth-bound model. Several recommendations are made in the appendix as to the changes needed in material selection for the lunar environment. The operator station is designed dimensionally correct for an astronaut wearing the current space shuttle EVA suit (which includes life support). The proposed operator station will support and restrain an astronaut as well as provide protection from the hazards of vehicle rollover. The threat of suit puncture is eliminated by rounding all corners and edges. A step-plate, located at the front of the vehicle, provides excellent ease of entry and exit. The operator station weight requirements are met by making efficient use of grid members, semi-rigid members and woven fabrics.

  10. Space Station Software Issues

    NASA Technical Reports Server (NTRS)

    Voigt, S. (editor); Beskenis, S. (editor)

    1985-01-01

    Issues in the development of software for the Space Station are discussed. Software acquisition and management, software development environment, standards, information system support for software developers, and a future software advisory board are addressed.

  11. Space Station Software Recommendations

    NASA Technical Reports Server (NTRS)

    Voigt, S. (editor)

    1985-01-01

    Four panels of invited experts and NASA representatives focused on the following topics: software management, software development environment, languages, and software standards. Each panel deliberated in private, held two open sessions with audience participation, and developed recommendations for the NASA Space Station Program. The major thrusts of the recommendations were as follows: (1) The software management plan should establish policies, responsibilities, and decision points for software acquisition; (2) NASA should furnish a uniform modular software support environment and require its use for all space station software acquired (or developed); (3) The language Ada should be selected for space station software, and NASA should begin to address issues related to the effective use of Ada; and (4) The space station software standards should be selected (based upon existing standards where possible), and an organization should be identified to promulgate and enforce them. These and related recommendations are described in detail in the conference proceedings.

  12. Breakup of the Larsen Ice Shelf, Antarctica

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Recent Moderate-resolution Imaging Spectroradiometer (MODIS) satellite imagery analyzed at the University of Colorado's National Snow and Ice Data Center revealed that the northern section of the Larsen B ice shelf, a large floating ice mass on the eastern side of the Antarctic Peninsula, has shattered and separated from the continent. This particular image was taken on March 5, 2002. The shattered ice formed a plume of thousands of icebergs adrift in the Weddell Sea. A total of about 3,250 square kilometers of shelf area disintegrated in a 35-day period beginning on January 31, 2002. Over the last five years, the shelf has lost a total of 5,700 square kilometers and is now about 40 percent the size of its previous minimum stable extent. Ice shelves are thick plates of ice, fed by glaciers, that float on the ocean around much of Antarctica. The Larsen B shelf was about 220 meters thick. Based on studies of ice flow and sediment thickness beneath the ice shelf, scientists believe that it existed for at least 400 years prior to this event and likely existed since the end of the last major glaciation 12,000 years ago. For reference, the area lost in this most recent event dwarfs Rhode Island (2,717 square kilometers) in size. In terms of volume, the amount of ice released in this short time is 720 billion tons--enough ice for about 12 trillion 10-kilogram bags. This is the largest single event in a series of retreats by ice shelves along the peninsula over the last 30 years. The retreats are attributed to a strong climate warming in the region. The rate of warming is approximately 0.5 degrees Celsius per decade, and the trend has been present since at least the late 1940s. Overall in the peninsula, the extent of seven ice shelves has declined by a total of about 13,500 square kilometers since 1974. This value excludes areas that would be expected to calve under stable conditions. Ted Scambos, a researcher with the National Snow and Ice Data Center (NSIDC) at University of Colorado, and a team of collaborating investigators developed a theory of how the ice disintegrates. The theory is based on the presence of ponded melt water on the surface in late summer as the climate has warmed in the area. Meltwater acts to enhance fracturing of the shelf by filling smaller cracks. The weight of the meltwater forces the cracks through the thickness of the ice. The idea was suggested in model form by other researchers in the past (Weertman, 1973; Hughes, 1983); satellite images have provided substantial observational proof that it is in fact the main process responsible for the peninsula shelf disintegration. Christina Hulbe of Portland State University and Mark Fahnestock of University of Maryland collaborated with Scambos on the research. For more information see: Antarctic Ice Shelf Collapses Image courtesy Ted Scambos, National Snow and Ice Data Center, University of Colorado, Boulder, based on data from MODIS

  13. Endophytic fungi associated with the Antarctic grass Deschampsia antarctica Desv. ( Poaceae )

    Microsoft Academic Search

    Luiz H. Rosa; Aline B. M. Vaz; Rachel B. Caligiorne; Sabrina Campolina; Carlos A. Rosa

    2009-01-01

    Deschampsia antarctica Desv. (Poaceae) represents one of the two vascular plants that have colonized the Antarctic continent, which is usually exposed to extreme\\u000a environmental conditions. In this work, we have characterized the endophytic fungi associated with the leaves of D. antarctica. Endophytic fungi were recovered from 91 individual plants from different points of Admiralty Bay at King George Island,\\u000a Antarctica. A total

  14. Caring Together: Activity Stations

    NSDL National Science Digital Library

    2014-04-30

    In this Bob the Builder(TM)-themed activity, learners explore the 3Rs (Reduce, Reuse, Recycle) by rotating through several activity stations. Activity stations may include: packing a lunch in reusable containers; sorting recyclable cans, plastic containers, and newspaper; playing with water in recycled containers and toys; making a collage by reusing magazine pictures; and drawing on both sides of the paper. This activity is featured on page 14 of the "Bob the Builder(TM) — Project: Build It" unit of study.

  15. Space station communications

    Microsoft Academic Search

    C. L. Cuccia

    1983-01-01

    A concise history of the various types of communications that have been used in low-earth-orbit vehicles and form the basis of the various types of communications and communication requirements that can be realized in space-station developments over the next decade is presented. The Space Shuttle can be assumed to be a prototype space station in the tradition of Apollo and

  16. Space Stations: Measure Up!

    NSDL National Science Digital Library

    Dr. Diane Byerly

    2006-01-01

    In this activity, learners work in pairs to measure each other's ankles with lengths of string. Learners make measurements both before and after lying on their backs with their feet in the air for 1 minute. This simulates the microgravity of space, where everything--including body fluids--floats! This activity station is part of a sequence of stations that can be set up to help learners explore how space affects the human body and why.

  17. Space Station - early

    NASA Technical Reports Server (NTRS)

    1961-01-01

    Manned Space Laboratory Research. James Hansen wrote: 'Testing indicated that the inflatable torus could be packaged around the hub so that it occupied only 2 percent of its inflated volume.' 'The first idea for an inflatable station was the Erectable Torus Manned Space Laboratory. A Langley space station team led by Paul Hill and Emanuel 'Manny' Schnitzer developed the concept with the help of the Goodyear Aircraft Corporation.'

  18. Characteristic Surface Processes Between Atmosphere, Cryosphere and Oceanic Environment Inferred from Infrasound Array Observations in Lützow-Holm Bay, East Antarctica

    NASA Astrophysics Data System (ADS)

    Ishihara, Y.; Kanao, M.; Yamamoto, M. Y.; Kakinami, Y.; Murayama, T.; Okada, K.; Toda, S.; Matsushima, T.

    2014-12-01

    Infrasound is sub-audible sound whose frequency range is about 3 mHz to 20 Hz. Because this frequency is common between atmospheric, oceanic and solid earth vibrations, those waves are interacting with each other and interaction itself generates infrasound. At polar region, cryosphere also play an important role for generation and propagation of infrasound. The Japanese Antarctic infrasound observation started at April 2008. A sensor was installed at Syowa Station (SYO) in Lützow-Holm Bay (LHB) of East Antarctica, as a part of the International Polar Year. Characteristic infrasound waves observed at SYO demonstrate physical interaction involving environmental changes in the Antarctic region. Continuous recordings of infrasound clearly indicate existence of the hums generated by ocean-atmosphere interaction (microbaroms) with peaks of 0.1 to 0.25 Hz. Because larger amount of sea-ice extending around the LHB near SYO suppress ocean wave, the microbaroms become weak during austral winter. Following success of pilot observation, in austral summer in 2013, we extended one-sensor observation at SYO to 3-sensor arrayed observations, and installed a few field stations along the coast of the LHB. Newly established SYO array clearly detected the propagating directions and frequency contents of the microbaroms from Southern Ocean. In addition, we found harmonic signals around lowermost human audible band, however, currently unclear how and what generating hamonic signals. Those signals are recorded under windy condition. Since our system has no mechanical resonance at those frequency ranges, we speculate that the characteristic harmonic signals are probably related to local surficial phenomena such as ice sheet vibration generated by katabatic winds. Infrasound measurement at Antarctica could be a new proxy for monitoring a regional environmental change in high southern latitude. In such point of view, we will continue and improve the observations at and around SYO, Antarctica.

  19. A Combined Observational and Modeling Approach to Study Modern Dust Transport from the Patagonia Desert to East Antarctica

    NASA Technical Reports Server (NTRS)

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

    2010-01-01

    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 (approx.54deg S) and from the shores of the Colihue Huapi lake in Central Patagonia (approx.46deg 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 de- position over the ocean immediately downwind. Boundary layer dust was detected as far as 1800 km from the source and approx.800 km north of the South Georgia Island over the central sub-Antarctic Atlantic Ocean. Although the analysis suggests the presence of dust at approx.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.

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

    NASA Astrophysics Data System (ADS)

    Rodríguez, Estefanía

    2012-06-01

    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.

  1. 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)

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

    2002-03-01

    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.

  2. Airborne laser scanning for high-resolution mapping of Antarctica

    NASA Astrophysics Data System (ADS)

    Csatho, Bea; Schenk, Toni; Krabill, William; Wilson, Terry; Lyons, William; McKenzie, Garry; Hallam, Cheryl; Manizade, Serdar; Paulsen, Timothy

    In order to evaluate the potential of airborne laser scanning for topographic mapping in Antarctica and to establish calibration/validation sites for NASA's Ice, Cloud and land Elevation Satellite (ICESat) altimeter mission, NASA, the U.S. National Science Foundation (NSF), and the U.S. Geological Survey (USGS) joined forces to collect high-resolution airborne laser scanning data.In a two-week campaign during the 2001-2002 austral summer, NASA's Airborne Topographic Mapper (ATM) system was used to collect data over several sites in the McMurdo Sound area of Antarctica (Figure 1a). From the recorded signals, NASA computed laser points and The Ohio State University (OSU) completed the elaborate computation/verification of high-resolution Digital Elevation Models (DEMs) in 2003. This article reports about the DEM generation and some exemplary results from scientists using the geomorphologic information from the DEMs during the 2003-2004 field season.

  3. First time-series optical photometry from Antarctica

    E-print Network

    K. G. Strassmeier; R. Briguglio; T. Granzer; G. Tosti; I. DiVarano; I. Savanov; M. Bagaglia; S. Castellini; A. Mancini; G. Nucciarelli; O. Straniero; E. Distefano; S. Messina; G. Cutispoto

    2008-07-18

    Beating the Earth's day-night cycle is mandatory for long and continuous time-series photometry and had been achieved with either large ground-based networks of observatories at different geographic longitudes or when conducted from space. A third possibility is offered by a polar location with astronomically-qualified site characteristics. Aims. In this paper, we present the first scientific stellar time-series optical photometry from Dome C in Antarctica and analyze approximately 13,000 CCD frames taken in July 2007. We conclude that high-precision CCD photometry with exceptional time coverage and cadence can be obtained at Dome C in Antarctica and be successfully used for time-series astrophysics.

  4. Polar ecosystem dynamics: recovery of communities from organic enrichment in McMurdo Sound, Antarctica.

    PubMed

    Kim, Stacy; Hammerstom, Kamille K; Conlan, Kathleen E; Thurber, Andrew R

    2010-12-01

    Community structure and diversity are influenced by patterns of disturbance and input of food. In Antarctica, the marine ecosystem undergoes highly seasonal changes in availability of light and in primary production. Near research stations, organic input from human activities can disturb the regular productivity regime with a consistent input of sewage. McMurdo Sound has both high-productivity and low-productivity habitats, thereby providing an ideal test bed for community recovery dynamics under polar conditions. We used experimental manipulations of the subtidal communities to test the hypotheses that (1) benthic communities respond differently to disturbance from organic enrichment versus burial and (2) community response also varies in areas with different natural patterns of food supply. Both in low- and high-food habitats, the strongest community response was to organic enrichment and resulted in dominance of typical organic-enrichment specialists. In habitats with highly seasonal productivity, community response was predictable and recovery was rapid. In habitats with low productivity, community variability was high and caging treatments suggested that inconsistencies were due to patchy impacts by scavengers. In areas normally subject to regular organic enrichment, either from primary production or from further up the food web (defecation by marine mammals), recovery of benthic communities takes only years even in a polar system. However, a low-productivity regime is as common in near shore habitats around the continent; under these conditions, recovery of benthic communities from disturbance is likely to be much slower and follow a variable ecological trajectory. PMID:21558257

  5. Planetary wave oscillations observed in ozone and PMSE data from Antarctica

    NASA Astrophysics Data System (ADS)

    Demissie, T. D.; Hosokawa, K.; Kleinknecht, N. H.; Espy, P. J.; Hibbins, R. E.

    2013-12-01

    The effect of temperature variations caused by planetary waves on the occurrence of Polar Mesospheric Summer Echoes (PMSE) has been a subject of recent research. These same temperature fluctuations have also been shown to modulate the ozone volume mixing ratio above 30 km. In this study, ground-based radiometer measurements of ozone mixing ratio profiles at Troll station (72°S, 2°E), Antarctica are compared with PMSE extracted from the near-range measurements of the Sanae (72°S, 2°W) Super Dual Auroral Radar (SuperDARN) over the radiometer field of view. We show here that the resulting quasi-periodic fluctuations in PMSE correlate with the variations seen in the ozone. The ozone mixing-ratio variations may then be used to trace the phase variation of planetary waves with height to demonstrate that they extend from the stratosphere up to the mesopause. The results indicate that the modulation of PMSE occurrence frequency during the summer of 2009/10 is the result of two planetary waves with similar zonal structure and period, but with different vertical phase structures.

  6. Cutaneous and diphtheritic avian poxvirus infection in a nestling Southern Giant Petrel (Macronectes giganteus) from Antarctica

    USGS Publications Warehouse

    Shearn-Bochsler, Valerie; Green, David Earl; Converse, K.A.; Docherty, D.E.; Thiel, T.; Geisz, H.N.; Fraser, William R.; Patterson-Fraser, Donna L.

    2008-01-01

    The Southern giant petrel (Macronectes giganteus) is declining over much of its range and currently is listed as vulnerable to extinction by the International Union for the Conservation of Nature (IUCN). Island-specific breeding colonies near Palmer Station, Antarctica, have been monitored for over 30 years, and because this population continues to increase, it is critically important to conservation. In austral summer 2004, six diseased giant petrel chicks were observed in four of these colonies. Diseased chicks were 6a??9 weeks old and had multiple proliferative nodules on their bills and skin. One severely affected chick was found dead on the nest and was salvaged for necropsy. Histopathological examination of nodules from the dead chick revealed epithelial cell hyperplasia and hypertrophy with numerous eosinophilic intracytoplasmic inclusions (B??llinger bodies). A poxvirus was isolated from multiple nodules. Poxviral infection has not been reported in this species, and the reason for its emergence and its potential impact on the population are not yet known.

  7. Annual cycle of landfast sea ice in Prydz Bay, east Antarctica

    NASA Astrophysics Data System (ADS)

    Lei, Ruibo; Li, Zhijun; Cheng, Bin; Zhang, Zhanhai; Heil, Petra

    2010-02-01

    Under the Chinese National Antarctic Research Expedition program in 2006, the annual thermal mass balance of landfast ice in the vicinity of Zhongshan Station, Prydz Bay, east Antarctica, was investigated. Sea ice formed from mid-February onward, and maximum ice thickness occurred in late November. Snow cover remained thin, and blowing snow caused frequent redistribution of the snow. The vertical ice salinity showed a "question-mark-shaped" profile for most of the ice growth season, which only turned into an "I-shaped" profile after the onset of ice melt. The oceanic heat flux as estimated from a flux balance at ice-ocean interface using internal ice temperatures decreased from 11.8 (±3.5) W m-2 in April to an annual minimum of 1.9 (±2.4) W m-2 in September. It remained low through late November, in mid-December it increased sharply to about 20.0 W m-2. Simulations applying the modified versions of Stefan's law, taking account the oceanic heat flux and ice-atmosphere coupling, compare well with observed ice growth. There was no obvious seasonal cycle for the thermal conductivity of snow cover, which was also derived from internal ice temperatures. Its annual mean was 0.20 (±0.04) W m-1 °C-1.

  8. A year-long record of size-segregated aerosol composition at Halley, Antarctica

    NASA Astrophysics Data System (ADS)

    Rankin, Andrew M.; Wolff, Eric W.

    2003-12-01

    Size-segregated aerosol samples were collected with a cascade impactor at 2 week intervals for a year at the research station Halley, situated near the coast in the Weddell Sea region of Antarctica. Sea salt is a major component of aerosol throughout the year, and we estimate that at least 60% of the total sea salt arriving at Halley is from brine and frost flowers on the sea ice surface rather than open water. Chloride in sea-salt particles is depleted relative to sodium in summer, consistent with loss of HCl as sea-salt particles react with gaseous acidic species, but is enhanced in large particles in winter because of fractionation occurring during the production of new sea ice. Non-sea-salt sulphate peaks in the summer, with the majority being in small particles indicative of a gas phase origin. The distribution of methane sulphonic acid closely follows that of non-sea-salt sulphate. In the winter, non-sea-salt sulphate is frequently negative, especially on stages collecting large particle sizes, consistent with the source of sea salt during the winter being predominantly the sea ice surface rather than open water. Nitrate peaks in the spring and summer and shows some association with sea-salt particles.

  9. Tides over Antarctica: Comparison of Whole Atmosphere Model (WAM) Simulations with Ground-Based Observations

    NASA Astrophysics Data System (ADS)

    Akmaev, R. A.; Murphy, D. J.; Luebken, F. J.; Forbes, J. M.

    2014-12-01

    Ground-based radar and optical observations of winds and temperature reveal a rich and variable spectrum of tidal oscillations in the mesosphere/lower thermosphere (MLT) over Antarctica, including the South Pole. Large-scale perturbations over the pole may formally be represented only with zonal wavenumbers 0 or 1. Only the latter may support winds and the only migrating tide that can exist over the pole is the diurnal westward DW1. Other tidal periods projecting on the permitted wavenumbers inevitably correspond to nonmigrating waves such as the well documented semidiurnal westward SW1. Migrating tides make a noticeable contribution over the edges of the continent posing an identification problem for stations on the ground. Free-running WAM simulations show good agreement in amplitude, phase, seasonal and day-to-day variability of prominent tides with observations by some ground-based instruments but less so with others. Because the model dynamics is self-consistent, this implies that estimates of tidal variations of different parameters, e.g., temperature and winds, or from different instruments cannot be all correct. More cross-validation and detailed analyses of estimate errors and biases are needed.

  10. High-resolution 900 year volcanic and climatic record from the Vostok area, East Antarctica

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

    Ion chromatography measurements of 1730 snow and firn samples obtained from three short cores and one pit in the Vostok station area, East Antarctica, allowed for the production of the combined volcanic record of the last 900 years (AD 1093-2010). The resolution of the record is 2-3 samples per accumulation year. In total, 24 volcanic events have been identified, including seven well-known low-latitude eruptions (Pinatubo 1991, Agung 1963, Krakatoa 1883, Tambora 1815, Huanaputina 1600, Kuwae 1452, El Chichon 1259) found in most of the polar ice cores. In comparison with three other East Antarctic volcanic records (South Pole, Plateau Remote and Dome C), the Vostok record contains more events within the last 900 years. The differences between the records may be explained by local glaciological conditions, volcanic detection methodology, and, probably, differences in atmospheric circulation patterns. The strongest volcanic signal (both in sulfate concentration and flux) was attributed to the AD 1452 Kuwae eruption, similar to the Plateau Remote and Talos Dome records. The average snow accumulation rate calculated between volcanic stratigraphic horizons for the period AD 1260-2010 is 20.9 mm H2O. Positive (+13%) anomalies of snow accumulation were found for AD 1661-1815 and AD 1992-2010, and negative (-12%) for AD 1260-1601. We hypothesized that the changes in snow accumulation are associated with regional peculiarities in atmospheric transport.

  11. Real-Time Mesoscale Modeling Over Antarctica: The Antarctic Mesoscale Prediction System*.

    NASA Astrophysics Data System (ADS)

    Powers, Jordan G.; Monaghan, Andrew J.; Cayette, Arthur M.; Bromwich, David H.; Kuo, Ying-Hwa; Manning, Kevin W.

    2003-11-01

    *Byrd Polar Research Center Contribution Number 1276In support of the United States Antarctic Program (USAP), the National Center for Atmospheric Research and the Byrd Polar Research Center of The Ohio State University have created the Antarctic Mesoscale Prediction System (AMPS): an experimental, real-time mesoscale modeling system covering Antarctica. AMPS has been designed to serve flight forecasters at McMurdo Station, to support science and operations around the continent, and to be a vehicle for the development of physical parameterizations suitable for polar regions. Since 2000, AMPS has been producing high-resolution forecasts (grids to 3.3 km) with the “Polar MM5,” a version of the fifth-generation Pennsylvania State University NCAR Mesoscale Model tuned for the polar atmosphere. Beyond its basic mission of serving the USAP flight forecasters at McMurdo, AMPS has assisted both in emergency operations to save lives and in programs to explore the extreme polar environment. The former have included a medical evacuation from the South Pole and a marine rescue from the continental margin. The latter have included scientific field campaigns and the daily activities of international Antarctic forecasters and researchers. The AMPS program has been a success in terms of advancing polar mesoscale NWP, serving critical logistical operations of the USAP, and, most visibly, assisting in emergency rescue missions to save lives. The history and performance of AMPS are described and the successes of this unique real-time mesoscale modeling system in crisis support are detailed.

  12. Quasi-Lagrangian measurements of nitric acid trihydrate formation over Antarctica

    NASA Astrophysics Data System (ADS)

    Ward, Shauna M.; Deshler, Terry; Hertzog, Albert

    2014-01-01

    In 2010, the joint French-United States Concordiasi project released 19 long-duration superpressure balloons from McMurdo Station, Antarctica. Four of these balloons carried a gondola with particle counters and temperature sensors to measure polar stratospheric clouds. One gondola spent 5 days at stable temperatures between equilibrium temperatures for nitric acid trihydrate (NAT) and for supercooled ternary solution droplets. Sporadic particles with radii between 0.46 µm and 4.5 µm were measured in a small fraction of the measurements. At these times the corresponding size distributions and total particle volumes were consistent with NAT. Although the fraction of these observations was less than 3%, their frequency increased with time over the 5 days. From this frequency the NAT nucleation rate at 3°C below TNAT was estimated to be 2 × 10-4 m-3 s-1 ± 60% for these late winter austral NAT observations at a potential temperature of 410-415 K. Interspersed with these measurements of polar stratospheric cloud particles consistent with NAT were many more measurements of particles consistent with background stratospheric aerosol indicating that the polar stratospheric clouds sampled were highly discontinuous.

  13. Human contamination of the marine environment - Arthur Harbor and McMurdo sound, Antarctica

    SciTech Connect

    Kennicutt, M.C. II; McDonald, S.J.; Sericano, J.L.; Boothe, P.; Oliver, J.; Safe, S.; Presley, B.J.; Liu, H.; Wade, T.L. [Texas A& M Univ., College Station, TX (United States); Wolfe, D. [NOAA, Silver Spring, MD (United States); Crockett, A. [Idaho National Engineering Lab., Idafo Falls, ID (United States); Bockus, D. [Moss Landing Marine Lab., CA (United States)

    1995-05-01

    Polycyclic aromatic hydrocarbons (PAH), polychlorinated biphenyls (PCBs), pesticides, and trace metal concentrations in McMurdo Sound and Arthur Harbor, Antarctica, sediments and marine biota are reported. Biomarkers of contaminant exposure, biliary metabolites and EROD assays, were also measured. Hydrocarbon and trace metal contamination are generally limited to within hundreds of meters of human settlements. Local releases of fossil fuels, disposal of waste materials, and aging of ship and station structures contribute to contamination. High concentrations of PCBs were detected in sediments (250-4200 ng g{sup -1}) and organisms (up to 420 ng g{sup -1}) from Winter Quarters Bay (WQB). Trace metal and PAH sediment concentrations rarely exceed levels known to cause toxic effects in marine organisms, whereas PCBs in WQB often do. Biological responses to exposure include the formation of PAH metabolites and the inducement of the P4501A detoxification system in fish. Induction of EROD activity in in vitro rat hepatoma H4IIE cell bioassays by tissue extracts correlated with known levels of PCB contamination in invertebrate tissues. Local sources of contaminants greatly exceed those attributable to long-distance atmospheric transport. 31 refs., 4 figs.

  14. A new species of Laonice (Spionidae, Polychaeta, Annelida) from Bellingshausen Sea (West Antarctica)

    NASA Astrophysics Data System (ADS)

    López, Eduardo

    2011-06-01

    During the Antarctic summers of 2002-2003 and of 2005-2006, the Spanish BENTART cruises were conducted to the Bellingshausen Sea (Western Antarctica), aiming to study its benthic communities, from depths ranging from 100 to 2,000 m. To achieve it, 30 stations were selected; each one was surveyed in such a way that the infaunal, epifaunal and suprabenthic components of the communities were sufficiently characterized. As a part of the study, some spionid individuals were identified as belonging to a new species of the genus Laonice Malmgren, 1867. The new species belongs to a group within the genus that is characterized by the presence of more than two rows of very numerous capillary chaetae in both noto- and neuropodial fascicles of anterior part of the body. However, it can be readily distinguished from the rest of species within the group by the posterior position in which neuropodial pouches appear (chaetiger 16 or 17) and by the caruncle reaching posteriorly chaetiger 19. In addition, other remarkable features of the new species are the short and triangular occipital tentacle, the rudimentary eyes, the hooded neuropodial hooks first appearing in chaetigers 34-37 and the sabre neurochaetae first occurring in chaetigers 20-27.

  15. Molecular characterisation of anthropogenic sources of sedimentary organic matter from Potter Cove, King George Island, Antarctica.

    PubMed

    Dauner, Ana Lúcia L; Hernández, Edgardo A; MacCormack, Walter P; Martins, César C

    2015-01-01

    Although relatively recent, human activities in Antarctica, such as growing tourism, fishery activities, and scientific operations, have affected some areas of this continent. These activities eventually release pollutants, such as petroleum and its derivatives and sewage, into this environment. Located on King George Island (25 de Mayo Island), Potter Cove (62°14'S, 58°39'W) is home to the Argentine Carlini research station. To evaluate the anthropogenic impacts surrounding Potter Cove, sediment samples were collected and analysed for sewage and fuel introduction via the determination of organic markers. The highest concentrations were found in the central portion of the fjords, where fine sediments are deposited and the accumulation of organic molecules is favoured. Aliphatic hydrocarbons were mainly derived from biogenic sources, evidenced by the predominance of odd short-chain n-alkanes. Anthropogenic impacts were evidenced primarily by the presence of PAHs, which were predominantly related to petrogenic sources, such as vessel and boat traffic. Sewage marker concentrations were much lower than those found in other Antarctic regions. These results indicate that oil hydrocarbons and sewage inputs to Potter Cove may be considered low or only slightly influential. PMID:25268570

  16. Sand dune movement in the Victoria Valley, Antarctica

    Microsoft Academic Search

    Mary C. Bourke; Ryan C. Ewing; David Finnegan; Hamish A. McGowan

    2009-01-01

    We use vertical aerial photographs and LiDAR topographic survey data to estimate dune migration rates in the Victoria Valley dunefield, Antarctica, between 1961 and 2001. Results confirm that the dunes migrated an average of 1.5 m\\/year. These values are consistent with other estimates of dune migration from cold climate deserts and are significantly lower than estimates from warm deserts. Dune migration

  17. Diversity of Soil Yeasts Isolated from South Victoria Land, Antarctica

    Microsoft Academic Search

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

    2008-01-01

    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

  18. SMOS over Antarctica - a short story of massive iceberg

    NASA Astrophysics Data System (ADS)

    Slominska, E.; Marczewski, W.; Slominski, J.

    2012-04-01

    By merging the SMOS land and sea L1C data, we obtain global maps of the brightness temperature at the top of the atmosphere at the L-band. This is a starting point for spatial and temporal analysis of the first Stokes parameter variations. One-year set of weakly averaged global maps of the first Stokes parameter clearly revealed dynamics of seasonal changes, especially at high latitudes and in the polar regions. It shows the changes in ice extent over Antarctica, ice melting in the Arctic Sea or the Hudson Bay. Current studies are focused only on the Southern Hemisphere, mainly Antarctica and the region of the Ross Sea, where we were able to detect with SMOS one of the biggest icebergs ever recorded (B15J - part of the B15 iceberg). For nearly a year, the drifting iceberg was tracked on the SMOS data. An isolated, floating along Antarctica, set of 8-10 SMOS DGG pixels was a focal point for the present analysis. It was characterised by an excess in brightness temperature of approximately 30K, when compared to surrounding open water. The derived iceberg motion indicated significant change of direction in the middle of September 2011, when the berg started to move equatorward. Straying from Antarctica, was accompanied with sequential decrease of the brightness temperature. At the end of December, the signatures of observed iceberg were barely apparent, making further tracking not feasible. It is highly probable that SMOS documented the final stage of evolution of B-15J. So apart from the motion track and speed, we examine the variations of the brightness temperature, as well as polarimetric characteristics of the spotted iceberg.

  19. Mapping Antarctica using Landsat-8 - the preliminary results

    NASA Astrophysics Data System (ADS)

    Cheng, X.; Hui, F.; Qi, X.

    2014-12-01

    The first Landsat Image Mosaic of Antarctica (LIMA) was released in 2009, which was created by USGS, BAS, and NASA from more than 1,000 Landsat ETM+ scenes. As the first major scientific outcome of the IPY, LIMA supports current scientific polar research, encourages new projects, and helps the general public visualize Antarctica and changes happening to this southernmost environment. As the latest satellite of Landsat mission, the Landsat-8 images the entire Earth every 16 days in an 8-day offset from Landsat-7. Data collected by the instruments onboard the satellite are available to download at no charge within 24 hours of reception. The standard Landsat 8 products provided by the USGS EROS Center consist of quantized and calibrated scaled Digital Numbers (DN) in 16-bit unsigned integer format and can be rescaled to the Top Of Atmosphere (TOA) reflectance and/or radiance. With the support of USGS portal, we searched and downloaded more than 1600 scenes of Level 1 T- Terrain Corrected Landsat 8 image products covering Antarctica from late 2013 to early 2014. These data were converted to planetary radiance for further processing. Since the distribution of clouds in these images are random and much complicated, statistics on the distribution of clouds were performed and then help to decide masking those thicker cloud to keep more useful information left and avoid observation holes. A preliminary result of the Landsat-8 mosaic of Antarctica under the joint efforts of Beijing Normal University, NSIDC and University of Maryland will be released on this AGU fall meeting. Comparison between Landsat 7 and 8 mosaic products will also be done to find the difference or advantage of the two products.

  20. Iron-titanium oxides of the Dufek intrusion, Antarctica

    Microsoft Academic Search

    A. B. Fono

    The Dufek intrusion is a stratiform mafic body 8 to 9 km thick underlying 24,000 to 34,000 km2 in the Pensacola Mountains, Antarctica. Textures, structures, magmatic stratigraphy, and chemical variation indicate that layered gabbros and related rocks ofthis body developed by crystal accumulation on a magma chamber floor. Major cumulus phases in the exposed part of the intrusion are plagioclase,

  1. Stable-isotope records from Dronning Maud Land, Antarctica

    Microsoft Academic Search

    Wolfgang Graf; Hans Oerter; Oskar Reinwarth; Willibald Stichler; Frank Wilhelms; Heinz Miller; Robert Mulvaney

    2002-01-01

    The European Project for Ice Coring in Antarctica (EPICA) includes a comprehensive pre-site survey on the inland ice plateau of Dronning Maud Land. This paper focuses on the investigation of the 18O content of shallow firn and ice cores.These coreswere datedby profiles derived from dielectric-profilingandcontinuous flow analysis measurements.The individual records were stacked in order to obtain composite chronol- ogies of

  2. Petrified peat from a permian coal bed in Antarctica

    USGS Publications Warehouse

    Schopf, J.M.

    1970-01-01

    Petrified plant remains that composed a Permian peat deposit occur at a coal horizon in a local area of Mount Augusta near the Beardmore Glacier in Antarctica. This discovery is the first in the entire Gondwana area that yields plant materials as exquisitely preserved as the materials of the well-known coal-ball localities of the Northern Hemisphere. A sampling of anatomical details is illustrated.

  3. Paleolimnology of the McMurdo Dry Valleys, Antarctica

    Microsoft Academic Search

    Peter T. Doran; Robert A. Wharton Jr; W. Berry Lyons

    1994-01-01

    The McMurdo Dry Valleys presently contain more than 20 permanent lakes and ponds, which vary markedly in character. All, with the exception of a hypersaline pond, have a perennial ice-cover. The dry valley lakes, and lakes in other ice-free regions of continental Antarctica, are unique on this planet in that they consistently maintain a thick year-round ice cover (2.8–6.0 m)

  4. Impact of anthropogenic transportation to Antarctica on alien seed viability

    Microsoft Academic Search

    K. A. Hughes; J. E. Lee; C. Ware; K. Kiefer; D. M. Bergstrom

    2010-01-01

    Antarctic ecosystems are at risk from the introduction of invasive species. The first step in the process of invasion is the\\u000a transportation of alien species to Antarctic in a viable state. However, the effect of long-distance human-mediated dispersal,\\u000a over different timescales, on propagule viability is not well known. We assessed the viability of Poa trivialis seeds transported to Antarctica from

  5. 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.

  6. Chemical composition of the sediment from Lake 20 (Antarctica)

    Microsoft Academic Search

    Renato BAUDO; Paola BARBERO; Monica BELTRAMI; Daria ROSSI

    Lake 20 (19,000 m2) is located on the coast of the Ross Sea, in the North-Central part of Victoria Land, and its surface is ice-free between the end of December and early February. Within the framework of the Italian National Research Programme in Antarctica, a study was made of the chemical composition of sediments from the lake, with the intention

  7. Biogeochemical Dynamics of Dissolved Si in Taylor Valley, Antarctica

    Microsoft Academic Search

    Heather Elizabeth Pugh

    2002-01-01

    ABSTRACT This thesis is part of the McMurdo Dry Valleys (MCM) Long-Tern Ecological Research (LTER) study in Southern Victoria Land, Antarctica. With the exception of the ice-covered lakes, there is little liquid water present in the valleys for most of the year. Chemical weathering is thought to occur more readily in warm and wet climates, however,recent research has shown that

  8. Report on the First International Symposium on Operational Weather Forecasting in Antarctica.

    NASA Astrophysics Data System (ADS)

    Turner, John; Pendlebury, Stephen; Cowled, Lance; Jacka, Kieran; Jones, Marjorie; Targett, Philip

    2000-01-01

    The First International Symposium on Operational Weather Forecasting in Antarctica was held in Hobart, Australia, from 31 August to 3 September 1998. There were 40 attendees at the meeting from Australia, Belgium, Brazil, China, France, Italy, Russia, and the United Kingdom. In recent years there has been considerable growth in the requirement for weather forecasts for the Antarctic because of the increases in complex scientific research activities and the rapid growth of tourism to the continent. At many of the research stations there are now sophisticated forecasting operations that make use of the data available from drifting buoys and automatic weather stations, the output from numerical weather prediction systems, and high resolution satellite imagery. The models have considerable success at predicting the synoptic-scale depressions that occur over the ocean and in the coastal region. However, the many mesoscale systems that occur, which are very important for forecasting local conditions, are not well represented in the model fields and their movement is mainly predicted via the satellite data. In the future it is anticipated that high resolution, limited-area models will be run for selected parts of the continent. The symposium showed that great advances had been made during recent years in forecasting for the Antarctic as a result of our better understanding of atmospheric processes at high latitudes, along with the availability of high resolution satellite imagery and the output of numerical models. Outstanding problems include the difficulty of getting all of the observations to the main analysis centers outside the Antarctic in a timely fashion, the lack of upper air data from the Antarctic Peninsula and the interior of the continent, and the poor representation of the Antarctic orography and high latitude processes in numerical models. An outcome of the symposium will be a weather forecasting handbook dealing with the entire continent.

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

    SciTech Connect

    Helbling, E.W.

    1993-01-01

    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.

  10. Valley floor climate observations from the McMurdo dry valleys, Antarctica, 1986-2000

    USGS Publications Warehouse

    Doran, P.T.; McKay, C.P.; Clow, G.D.; Dana, G.L.; Fountain, A.G.; Nylen, T.; Lyons, W.B.

    2002-01-01

    Climate observations from the McMurdo dry valleys, East Antarctica are presented from a network of seven valley floor automatic meteorological stations during the period 1986 to 2000. Mean annual temperatures ranged from -14.8??C to -30.0??C, depending on the site and period of measurement. Mean annual relative humidity is generally highest near the coast. Mean annual wind speed increases with proximity to the polar plateau. Site-to-site variation in mean annual solar flux and PAR is due to exposure of each station and changes over time are likely related to changes in cloudiness. During the nonsummer months, strong katabatic winds are frequent at some sites and infrequent at others, creating large variation in mean annual temperature owing to the warming effect of the winds. Katabatic wind exposure appears to be controlled to a large degree by the presence of colder air in the region that collects at low points and keeps the warm less dense katabatic flow from the ground. The strong influence of katabatic winds makes prediction of relative mean annual temperature based on geographical position (elevation and distance from the coast) alone, not possible. During the summer months, onshore winds dominate and warm as they progress through the valleys creating a strong linear relationship (r2 = 0.992) of increasing potential temperature with distance from the coast (0.09??C km-1). In contrast to mean annual temperature, summer temperature lends itself quite well to model predictions, and is used to construct a statistical model for predicting summer dry valley temperatures at unmonitored sites. Copyright 2002 by the American Geophysical Union.

  11. Widespread thinning of the Amudsen Sea sector of West Antarctica

    NASA Astrophysics Data System (ADS)

    Rignot, E.; Zwally, J.

    2002-12-01

    We present a synergistic analysis of interferometric synthetic-aperture radar (InSAR) observations of ice flow at the grounding line and satellite radar altimetry (SRA) observations of elevation change to determine the present evolution of the Amundsen Sea sector of West Antarctica. InSAR reveals that the grounding line of large glaciers is retreating rapidly, which indicates thinning; and that several major glaciers are accelerating, hence increasing their contribution to sea level rise with time. The calculated mass budget of the two largest ice streams, Pine Island and Thwaites glaciers, is certainly negative, but even larger imbalances are calculated for smaller glaciers such as Smith, Kohler, DeVicq and Land. SRA observations confirm that the elevation of this sector of the ice sheets is decreasing with time, with thinning larger nearer to the coast and propagating hundreds of km inland. The combination of mass budget and elevation change suggest that this sector of Antarctica is losing enough mass to raise global sea level by 0.2 mm/yr. In addition, SRA reveals that large sectors of ice shelves are thinning rapidly, up to 4 m/yr on Dotson ice shelf. Melting of the ice shelves does not raise sea level, but the ice shelves may exert some control on the ice discharge from the glaciers. If the ice shelves buttress the glaciers, the contribution to sea level rise of this sector of Antarctica may be larger in the future.

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

    PubMed

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

    2013-01-01

    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

  13. Inter-annual sea-ice dynamics and micro-algal biomass in winter pack ice of Marguerite Bay, Antarctica

    E-print Network

    Stewart, Frank

    , Antarctica Christian H. Fritsen a,Ã, Jeramie Memmott a , Frank J. Stewart b a Division of Earth and Ecosystem Antarctica Southern Ocean a b s t r a c t The geographic remoteness, the lack of remote sensing capabilities

  14. Space station contamination modeling

    NASA Technical Reports Server (NTRS)

    Gordon, T. D.

    1989-01-01

    Current plans for the operation of Space Station Freedom allow the orbit to decay to approximately an altitude of 200 km before reboosting to approximately 450 km. The Space Station will encounter dramatically increasing ambient and induced environmental effects as the orbit decays. Unfortunately, Shuttle docking, which has been of concern as a high contamination period, will likely occur during the time when the station is in the lowest orbit. The combination of ambient and induced environments along with the presence of the docked Shuttle could cause very severe contamination conditions at the lower orbital altitudes prior to Space Station reboost. The purpose here is to determine the effects on the induced external environment of Space Station Freedom with regard to the proposed changes in altitude. The change in the induced environment will be manifest in several parameters. The ambient density buildup in front of ram facing surfaces will change. The source of such contaminants can be outgassing/offgassing surfaces, leakage from the pressurized modules or experiments, purposeful venting, and thruster firings. The third induced environment parameter with altitude dependence is the glow. In order to determine the altitude dependence of the induced environment parameters, researchers used the integrated Spacecraft Environment Model (ISEM) which was developed for Marshall Space Flight Center. The analysis required numerous ISEM runs. The assumptions and limitations for the ISEM runs are described.

  15. International space station

    NASA Astrophysics Data System (ADS)

    DeLucas, Lawrence J.

    1996-02-01

    The International Space Station represents the largest scientific and technological cooperative program in history, drawing on the resources of thirteen nations. The early stages of construction will involve significant participation from the Russian Space Agency (RSA), numerous nations of the European Space Agency (ESA), and the space agencies of Canada (CSA), Japan (NASDA) and the United States Space Agency (NASA). Its purpose is to place a unique, highly capable laboratory in tower orbit, where high value scientific research can be performed in microgravity. In addition to providing facilities where an international crew of six astronaut-scientists can live and work in space, it will provide important laboratory research facilities for performing basic research in life science, biomedical and material sciences, as well as space and engineering technology development which cannot be accomplished on Earth. The Space Station will be comprised of numerous interlocking components which are currently being constructed on Earth. Space Station will be assembled in orbit over a period of time and will provide several experimentation modules as well as habitation modules and interfaces for logistic modules. Including the four extensive solar rays from which it will draw electrical power, the Station will measure more than 300 feet wide by 200 feet long. This paper will present an overview of the various phases of construction of the Space Station and the planned science thought will be performed during the construction phase and after completion.

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

    Microsoft Academic Search

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

    2004-01-01

    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

  17. Progressive Cenozoic cooling and the demise of Antarctica’s last refugium

    PubMed Central

    Anderson, John B.; Warny, Sophie; Askin, Rosemary A.; Wellner, Julia S.; Bohaty, Steven M.; Kirshner, Alexandra E.; Livsey, Daniel N.; Simms, Alexander R.; Smith, Tyler R.; Ehrmann, Werner; Lawver, Lawrence A.; Barbeau, David; Wise, Sherwood W.; Kulhanek, Denise K.; Weaver, Fred M.; Majewski, Wojciech

    2011-01-01

    The Antarctic Peninsula is considered to be the last region of Antarctica to have been fully glaciated as a result of Cenozoic climatic cooling. As such, it was likely the last refugium for plants and animals that had inhabited the continent since it separated from the Gondwana supercontinent. Drill cores and seismic data acquired during two cruises (SHALDRIL I and II) in the northernmost Peninsula region yield a record that, when combined with existing data, indicates progressive cooling and associated changes in terrestrial vegetation over the course of the past 37 million years. Mountain glaciation began in the latest Eocene (approximately 37–34 Ma), contemporaneous with glaciation elsewhere on the continent and a reduction in atmospheric CO2 concentrations. This climate cooling was accompanied by a decrease in diversity of the angiosperm-dominated vegetation that inhabited the northern peninsula during the Eocene. A mosaic of southern beech and conifer-dominated woodlands and tundra continued to occupy the region during the Oligocene (approximately 34–23 Ma). By the middle Miocene (approximately 16–11.6 Ma), localized pockets of limited tundra still existed at least until 12.8 Ma. The transition from temperate, alpine glaciation to a dynamic, polythermal ice sheet took place during the middle Miocene. The northernmost Peninsula was overridden by an ice sheet in the early Pliocene (approximately 5.3–3.6 Ma). The long cooling history of the peninsula is consistent with the extended timescales of tectonic evolution of the Antarctic margin, involving the opening of ocean passageways and associated establishment of circumpolar circulation. PMID:21709269

  18. Postdepositional losses of methane sulfonate, nitrate, and chloride at the European Project for Ice Coring in Antarctica

    E-print Network

    Fischer, Hubertus

    Coring in Antarctica deep-drilling site in Dronning Maud Land, Antarctica R. Weller,1 F. Traufetter,1,2 H) drilling site in Dronning Maud Land (DML) (75°S, 0°E). Analyses of four intermediate deep firn cores and 13, and chloride at the European Project for Ice Coring in Antarctica deep-drilling site in Dronning Maud Land

  19. The Earth Institute, Columbia University8 annual donor report 2010 9 the ice sheets of antarctica are not

    E-print Network

    -Doherty researchers joined a massive NASA expedition to study the edges of Antarctica and the behavior of the iceThe Earth Institute, Columbia University8 annual donor report 2010 9 the ice sheets of antarctica our oceans. West Antarctica alone, an increasingly unstable ice sheet that rests on the ocean floor

  20. Molecular mechanism of the hydration of Candida antarctica1 lipase B in gas phase: water adsorption isotherms and molecular2

    E-print Network

    Paris-Sud XI, Université de

    1 Molecular mechanism of the hydration of Candida antarctica1 lipase B in gas phase: water of Candida antarctica lipase B34 (CALB) and its dependence on the thermodynamic activity of water aw antarctica lipase B (CALB) is an efficient catalyst for hydrolysis of ester substrates63 in water

  1. Organic pollutants and their correlation with stable isotopes in1 vegetation from King George Island, Antarctica2

    E-print Network

    Boyer, Edmond

    Island, Antarctica2 3 4 Caio V. Z. Cipro1,* , Gilvan Takeshi Yogui2 , Paco Bustamante3 , Satie Taniguchi1.chemosphere.2011.07.047 #12;2 Abstract: Vegetation samples from King George Island, Antarctica (62º05'S, 058º23'W antarctica), mosses (Sanionia uncinata, Syntrichia princeps and Brachytecium sp.), and one23 angiosperm

  2. Enantioselective acylation of R-2-pentanol in a solid/gas reactor catalysed by lipase B from Candida antarctica.

    E-print Network

    Paris-Sud XI, Université de

    from Candida antarctica. Valérie LEONARD, Sylvain LAMARE, Marie-Dominique LEGOY and Marianne GRABER reaction carried out in liquid systems. This reaction was catalysed by lipase B from Candida antarctica-added organic component on the other hand. Keywords (five): Lipase B from Candida antarctica; enantioselectivity

  3. THE PRECIPITATION REGIME OF DRONNING MAUD LAND, ANTARCTICA, DERIVED FROM AMPS (ANTARCTIC MESOSCALE PREDICTION SYSTEM) ARCHIVE DATA

    E-print Network

    Schlosser, Elisabeth

    THE PRECIPITATION REGIME OF DRONNING MAUD LAND, ANTARCTICA, DERIVED FROM AMPS (ANTARCTIC MESOSCALE research is the study of ice cores from the two large ice sheets of Greenland and Antarctica. Valuable for any ice core study. Under the European project EPICA (European Project for Ice Coring in Antarctica

  4. Russian Scientists Breach Antarctica's Lake Vostok--Confirmed1 by Christine Dell'Amore for National Geographic News2

    E-print Network

    South Bohemia, University of

    Russian Scientists Breach Antarctica's Lake Vostok--Confirmed1 by Christine Dell'Amore for National Geographic News2 3 Russian scientists have confirmed that they have penetrated Antarctica's Lake Vostok--that have been discovered under18 Antarctica in past decades. The project to probe the Great Lake-size water

  5. Alcoholysis catalyzed by Candida antarctica lipase B in a gas/solid system : effects of water on kinetic parameters

    E-print Network

    Paris-Sud XI, Université de

    1 Alcoholysis catalyzed by Candida antarctica lipase B in a gas/solid system : effects of water from Candida antarctica ­ kinetics ­ transesterification ­ water ­ solid/gas biocatalysis - hydration propionate and n-propanol catalyzed by immobilized lipase B from Candida antarctica was studied

  6. Crustal structure of the Gamburtsev Mountains, East Antarctica, from S-wave receiver functions and Rayleigh wave phase velocities

    E-print Network

    Crustal structure of the Gamburtsev Mountains, East Antarctica, from S-wave receiver functions der Hilst Keywords: Gamburtsev Mountains Antarctica crustal structure S-wave receiver functions The Gamburtsev Subglacial Mountains (GSM), located in central East Antarctica, are one of the most enigmatic

  7. Numerical simulations of convection in crystal-bearing magmas: A case study of the magmatic system at Erebus, Antarctica

    E-print Network

    Paris-Sud XI, Université de

    at Erebus, Antarctica Indira Molina,1,2,3 Alain Burgisser,1,2,3 and Clive Oppenheimer1,2,4 Received 9 August-bearing magmas: A case study of the magmatic system at Erebus, Antarctica, J. Geophys. Res., 117, B07209, doi:10 in Antarctica [Oppenheimer and Kyle, 2008, and references therein], Nyiragongo in the Democratic Republic

  8. Airborne-radar and ice-core observations of annual snow accumulation over Thwaites Glacier, West Antarctica confirm

    E-print Network

    Howat, Ian M.

    Antarctica confirm the spatiotemporal variability of global and regional atmospheric models B. Medley,1,2 I variations of snow accumulation over Thwaites Glacier, West Antarctica between 1980 and 2009. We also present a regional evaluation of modeled accumulation in Antarctica. Comparisons between radar-derived measurements

  9. Responses of polar mesospheric cloud brightness to stratospheric gravity waves at the South Pole and Rothera, Antarctica

    E-print Network

    Chu, Xinzhao

    and Rothera, Antarctica Xinzhao Chu a,Ã, Chihoko Yamashita a , Patrick J. Espy b , Graeme J. Nott c , Eric J mesospheric clouds Gravity waves Lidar Antarctica Stratosphere a b s t r a c t We present the first and Rothera (67.51S, 68.01W), Antarctica. Stratospheric GW strength is characterized by the root

  10. LETTER Earth Planets Space, 52, 10371041, 2000 The search for postglacial rebound near the Lambert Glacier, Antarctica

    E-print Network

    Tregoning, Paul

    Glacier, Antarctica Paul Tregoning, Andrew Welsh, Herbert McQueen, and Kurt Lambeck Research School vertical crustal movement in the Lambert Glacier region, East Antarctica. The program commenced in January equipment in Antarctica, provide predictions of the expected rate of rebound and comment on preliminary

  11. The History of Astrophysics in Antarctica Ahn, H. S., et al. 2002, Advanced Thin Ionization Calorimeter (ATIC) Update, American Physical

    E-print Network

    Burton, Michael

    The History of Astrophysics in Antarctica References Ahn, H. S., et al. 2002, Advanced Thin, in ASP Conf. Ser. 141, Astrophysics from Antarctica, ed. G. Novak & R. H. Landsberg (San Francisco, CA in the Keyhole Nebula, MNRAS, 319, 95 Burton, M. G. 1996, Why Antarctica?, PASA, 13, 2 Burton, M. G., Allen, D. A

  12. High resistance to oxidative damage in the Antarctic midge Belgica antarctica, and developmentally linked expression of genes encoding superoxide

    E-print Network

    Lee Jr., Richard E.

    High resistance to oxidative damage in the Antarctic midge Belgica antarctica, and developmentally by the Antarctic midge, Belgica antarctica, to counter oxidative stress. We cloned genes encoding two key challenges of low temperature and desiccation, organisms living in Antarctica are bombarded with especially

  13. Ecological Biogeography of the Terrestrial Nematodes of Victoria Land, Antarctica 29 Ecological Biogeography of theTerrestrial

    E-print Network

    Wall, Diana

    Ecological Biogeography of the Terrestrial Nematodes of Victoria Land, Antarctica 29 Ecological Biogeography of theTerrestrial Nematodes ofVictoria Land,Antarctica Byron J. Adams1 , Diana H. Wall2 , Ross A of the Terrestrial Nematodes of Victoria Land, Antarctica. ZooKeys 419: 29­71. doi: 10.3897/zookeys.419.7180 Abstract

  14. Solar power station

    SciTech Connect

    Wenzel, J.

    1982-11-30

    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.

  15. Modular space station facilities.

    NASA Technical Reports Server (NTRS)

    Parker, P. J.

    1973-01-01

    The modular space station will operate as a general purpose laboratory (GPL). In addition, the space station will be able to support many attached or free-flying research and application modules that would be dedicated to specific projects like astronomy or earth observations. The GPL primary functions have been organized into functional laboratories including an electrical/electronics laboratory, a mechanical sciences laboratory, an experiment and test isolation laboratory, a hard data process facility, a data evaluation facility, an optical sciences laboratory, a biomedical and biosciences laboratory, and an experiment/secondary command and control center.

  16. Space station propulsion options

    NASA Technical Reports Server (NTRS)

    Wilkinson, C. L.; Brennan, S. M.; Valgora, M. E.

    1985-01-01

    The selection of the propulsion system for the Space Station represents a complex issue. The present paper provides a summary of the Station design factors which dictate the propulsion requirements, taking into account approaches for meeting these requirements. Factors which affect propulsion system selection are related to thrusting strategy, volume and mass limitations, safety and contamination, electrical power, time phasing, synergistic opportunities, propellant scavenging, water electrolysis, and free-flyers. In a discussion of propulsion systems, attention is given to monopropellant options, bipropellant options, and resistojets.

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

    NASA Astrophysics Data System (ADS)

    Keskin, Siddik Sinan

    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 between 1969 A.D. and 1989 A.D. showed an enhanced impact on the Antarctic ice sheets from natural sources in the form of marine and crustal aerosols. A disturbed ocean-atmosphere interface due to El Nino Southern Oscillation (ENSO) events seems to be a candidate especially for the enhanced marine aerosol deposition in Antarctica. Time-series trend of the concentration of deposited aluminum, which is mainly a crustal aerosol related element, shows a strong negative correlation with the time-series trend of annual average total column ozone concentrations homogenized between the 60^circS and 90^circS latitudes from the Total Ozone Mapping Spectrometer (TOMS) ozone data set. Although the time period is not long enough to draw a strong conclusion (1979-1989), tbe special role of crustal origin clay minerals on cloud nucleation dynamics might be a factor in the heterogeneous stratospheric ozone depletion chemistry through polar stratospheric cloud dynamics, assuming some troposphere-stratosphere mixing of these aerosols. The correlation of antimony and arsenic enrichments with known or suspected volcanic events was established. These marker elements was shown to be useful especially for the identification of specific historical volcanic events with low sulfur emissions. Although a cleat anthropogenic impact was not observed, concentrations of arsenic, chromium. and zinc, which might come from both natural and anthropogenic sources, indicated an increase after 1960's. Principal component factor analysis indicated a possible transition-metal (especially manganese and iron) catalyzed bromine chemistry cycle, which has been suggested as the cause of tropospheric surface-level ozone depletion observed in Greenland. Calculated snow-to-air scavenging ratios indicated more efficient scavenging for crustal aerosols followed by marine and volatile elements. A new method was developed for direct air content determination in small deep ice core samples through the measurement of enclosed argon gas by instrumental neutron activation analysis. (Copies available exclusively from MIT Libraries, Rm. 14-0551, Cambridge, MA 02139-4307. Ph. 617 -253-5668; Fax 617-253-1690.).

  18. CryoSat-2 validation in East Antarctica: ASIRAS, ALS and in situ data analysis over Law Dome and Totten Glacier

    NASA Astrophysics Data System (ADS)

    Watson, C.; Burgette, R. J.; Helm, V.; Roberts, J. L.; Young, N. W.; Beardsley, J.; Tregoning, P.; Coleman, R.; Steinhage, D.; Fricker, H. A.; Young, D. A.; Blankenship, D. D.

    2012-12-01

    The joint TOT-Cal / CryoVExANT2011 project contributes to the validation of the CryoSat-2 altimetry mission through investigations of a key portion of the East Antarctic ice sheet near Australia's Casey Station. Spanning parts of Law Dome and the Totten Glacier, the study site includes a diverse range of along and across track surface slopes (ranging from 0° to over 2°), significant spatial variability in accumulation rate, as well as significant regions with known surface lowering (at rates greater than 1 m/yr). These characteristics combine to provide valuable validation targets for the CryoSat-2 mission. Two field campaigns at the study site have been completed during the 2010/11 and 2011/12 austral summer field seasons. In 2010/11, the primary in situ data collected included skidoo based kinematic GPS transects and airborne nadir pointing laser observations of the surface elevation (from ICECAP flights of Operation ICEBridge). In 2011/12, the AWI Polar-6 aircraft successfully completed aerial surveys across the region equipped with the scanning LiDAR and the ESA Airborne SAR / Interferometric Altimeter System (ASIRAS). These datasets combine with in-situ GPS observations (fixed stations and skidoo-based kinematic sampling), corner cube reflector placements and snow pit surveys. Together, these data provide a number of near contemporaneous observations of surface elevation and firn characteristics along CryoSat-2 ground tracks. Through repeated airborne observation, an insight into temporal changes over the most dynamic parts of the Totten Glacier where focused surface lowering and mass loss is known to be occurring can be achieved. In this contribution, we present early results investigating spatial variability present in the 2011/12 ASIRAS data, as well as temporal changes observed between successive acquisitions of airborne laser data (2010/11 and 2011/12). Comparison with CryoSat-2 SAR-In data is also presented.

  19. Return to Coalsack Bluff and the Permian Triassic boundary in Antarctica

    Microsoft Academic Search

    Gregory J. Retallack; Tara Greaver; A. Hope Jahren

    2007-01-01

    Coalsack Bluff was the first discovery site in Antarctica for the latest Permian to earliest Triassic reptile Lystrosaurus. This together with discovery of Permian Glossopteris leaves during the heroic age of Antarctic exploration, indicated not only that Antarctica was part of Gondwanaland, but also that Antarctic rocks recorded faunas from the greatest of all mass extinctions at the Permian Triassic

  20. Modeled methanesulfonic acid (MSA) deposition in Antarctica and its relationship to sea ice

    E-print Network

    Holmes, Christopher D.

    Modeled methanesulfonic acid (MSA) deposition in Antarctica and its relationship to sea ice P. J] Methanesulfonic acid (MSA) has previously been measured in ice cores in Antarctica as a proxy for sea ice extent experiments, we identify mechanisms that control the MSA concentrations recorded in ice cores. Sea ice

  1. Atmospheric signals and characteristics of accumulation in Dronning Maud Land, Antarctica

    Microsoft Academic Search

    David Noone; John Turner; Robert Mulvaney

    1999-01-01

    With the planned European Program for Ice Coring in Antarctica in Dronning Maud Land it is important to understand the processes leading to accumulation for successful interpretation of core data. Because it is impractical to obtain precipitation observations with a large spatial coverage and on a daily timescale in Antarctica, model-generated precipitation must be considered for a comprehensive study of

  2. X.R.F ANALYSES OF GRANITOIDS AND ASSOCIATED ROCKS FROM SOUTH VICTORIA LAND, ANTARCTICA

    E-print Network

    #12;X.R.F ANALYSES OF GRANITOIDS AND ASSOCIATED ROCKS FROM SOUTH VICTORIA LAND, ANTARCTICA K of the earliest geological studies of Antarctica. Indeed as early as 1841 granitoids were dredged from the sea described granitoids collected in situ by members of the Discovery expedition (1901-1904). Some years later

  3. Evidence of Little Ice Age in an East Antarctica Ice Core

    Microsoft Academic Search

    J. Cole-Dai; Y. Li; L. Zhou

    2003-01-01

    An 80 meter ice core was retrieved from an East Antarctica location (76° S, 77° E) by the Chinese Antarctica Research Expedition in 1999. Chemical analysis of the ice core has yielded a record of ionic impurities in snow for the past 800 years (1200-1999 A.D.). The ice core is dated using a combination of annual layer counting and volcanic

  4. Nutritional and psycho-physiological assessment of members of the XVI Antarctica expedition

    Microsoft Academic Search

    NARINDER K. SATIJA; ANAJANA G. VIJ; K. SRIDHARAN

    2000-01-01

    The present studies are aimed to evaluate the effects of physiological stress and metabolic requirements necessary to maintain homeostasis and physical and mental functions during stay at Antarctica in expedition members. Nutritional and psycho-physiological assement of the members of the XVI Indian Scientific Expedition to Antarctica was carried alongwith supplementation of vitamins, viz., vitamins, viz., vitamin C and vitamin E

  5. Analysis of deep-penetrating radar surveys of West Antarctica, US-ITASE 2001

    E-print Network

    Jacobel, Robert W.

    Analysis of deep-penetrating radar surveys of West Antarctica, US-ITASE 2001 Brian C. Welch echo- sounding (RES) data in West Antarctica along the 2001 US leg of the International Trans-Antarctic Scientific Expedition traverse (US-ITASE). These data represent the first high-resolution measurements of ice

  6. BIG SKY, MONTANA--Wetlands might seem incongruous in Antarctica's frozen wastes.

    E-print Network

    Christner, Brent C.

    BIG SKY, MONTANA--Wetlands might seem incongruous in Antarctica's frozen wastes. But recent expeditions have uncovered a hid- den landscape of lakes, marshes, and appar- ent rivers sandwiched between is likely to occur in Lake Vostok, the largest of Antarctica's 150-and-counting hidden lakes. A Russian

  7. Environmental factors influencing microbial growthinside th e historic expedition huts of Ross Island, Antarctica

    Microsoft Academic Search

    B. W. Held; B. E. Arenz; S. M. Duncan; R. L. Farrell; R. A. Blanchette

    Explorers to Antarctica during the Heroic Era of exploration built three wooden huts on Ross Island, Antarctica in 1902, 1908 and 1911. The structures were used as bases of operation while their occupants participated in scientific endeavors and strived to reach the South Pole. The huts, and the thousands of artifacts in and around them, have survived in the Antarctic

  8. Biophysiological changes observed in members of the Italian expeditions to Antarctica

    Microsoft Academic Search

    R. Mattei; A. Peri; G. Taviani; G. Vignacastrisi; F. Ferretti; E. Paolini; A. Grosso; S. Petralia; S. Ciardullo; S. Caroli

    2009-01-01

    The objective of this study was to investigate whether food consumed by individuals working in Antarctica is adequate and sufficient, from the nutritional viewpoint, to sustain life in extreme environments. Malnutrition can be the cause of both health impairment and reduction in psychological and physiological efficiency. The study involved individuals from two subsequent expeditions in Antarctica, namely, 34 subjects (group

  9. Environmental factors influencing microbial growth inside the historic expedition huts of Ross Island, Antarctica

    Microsoft Academic Search

    B. W. Held; J. A. Jurgens; B. E. Arenz; S. M. Duncan; R. L. Farrell; R. A. Blanchette

    2005-01-01

    Explorers to Antarctica during the Heroic Era of exploration built three wooden huts on Ross Island, Antarctica in 1902, 1908 and 1911. The structures were used as bases of operation while their occupants participated in scientific endeavors and strived to reach the South Pole. The huts, and the thousands of artifacts in and around them, have survived in the Antarctic

  10. 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...

  11. Toxin production in cyanobacterial mats from ponds on the McMurdo Ice Shelf, Antarctica

    Microsoft Academic Search

    B. C. Hitzfeld; C. S. Lampert; N. Spaeth; D. Mountfort; H. Kaspar; D. R. Dietrich

    2000-01-01

    Cyanobacteria are known to produce hepatotoxic substances, the functional and ecological role of these toxins, however, remains largely unclear. Toxic properties of cyanobacteria collected in Antarctica were investigated to determine whether toxin-producing species can also be found under these environmental conditions. Samples were collected from meltwater ponds on the McMurdo Ice Shelf, Antarctica in the summers of 1997 to 1999.

  12. PRODUCTION OF ITACONIC ACID BY PSEUDOZYMA ANTARCTICA NRRL Y-7808 UNDER NITROGEN-LIMITED GROWTH CONDITIONS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pseudozyma antarctica NRRL Y-7808 was found to produce itaconic acid from glucose and other sugars under nitrogen-limited growth conditions. Other Pseudozyma strains screened, including a second strain of Pseudozyma antarctica, did not produce this product; so itaconic acid production is not a comm...

  13. Tide Model Accuracy in the Amundsen Sea, Antarctica, from InSAR Observations of Ice

    E-print Network

    Tide Model Accuracy in the Amundsen Sea, Antarctica, from InSAR Observations of Ice Shelf Motion.mcmillan@leeds.ac.uk. Abstract Tide Model Evaluation This study assesses the accuracy of tide model predictions in the Amundsen Sea Sector of West Antarctica. · Tide model accuracy in this remote region is poorly constrained, yet

  14. Performance of bismuth germanate active shielding on a balloon flight over Antarctica

    SciTech Connect

    Rester, A.C.; Coldwell, R.L. (Institute for Astrophysics and Planetary Exploration, Univ. of Florida, Alachua, FL (US)); Trombka, J.I. (National Aeronautics and Space Administration, Greenbelt, MD (USA). Goddard Space Flight Center); Starr, R. (Catholic Univ. of America, Washington, DC (USA). Dept. of Physics); Eichhorn, G. (Steward Observatory, Tucson, AZ (USA)); Lasche, G.P. (Defense Advanced Research Projects Agency, Arlington, VA (USA))(Defense Advanced Research Projects Agency, Arlington, VA (USA))

    1990-04-01

    The GRAD gamma-ray spectrometer was flown on a high-altitude balloon at an altitude of 36.6 km over Antarctica on January 8-10, 1988 where it was used to make observations of Supernova 1987a. The performance of the bismuth germinate active shielding in the near-space environment over Antarctica is examined.

  15. Space Station Water Quality

    NASA Technical Reports Server (NTRS)

    Willis, Charles E. (editor)

    1987-01-01

    The manned Space Station will exist as an isolated system for periods of up to 90 days. During this period, safe drinking water and breathable air must be provided for an eight member crew. Because of the large mass involved, it is not practical to consider supplying the Space Station with water from Earth. Therefore, it is necessary to depend upon recycled water to meet both the human and nonhuman water needs on the station. Sources of water that will be recycled include hygiene water, urine, and cabin humidity condensate. A certain amount of fresh water can be produced by CO2 reduction process. Additional fresh water will be introduced into the total pool by way of food, because of the free water contained in food and the water liberated by metabolic oxidation of the food. A panel of scientists and engineers with extensive experience in the various aspects of wastewater reuse was assembled for a 2 day workshop at NASA-Johnson. The panel included individuals with expertise in toxicology, chemistry, microbiology, and sanitary engineering. A review of Space Station water reclamation systems was provided.

  16. Backyard Weather Station

    NSDL National Science Digital Library

    2014-09-18

    Students use their senses to describe what the weather is doing and predict what it might do next. After gaining a basic understanding of weather patterns, students act as state park engineers and design/build "backyard weather stations" to gather data to make actual weather forecasts.

  17. Station-keeping guidance

    NASA Technical Reports Server (NTRS)

    Gustafson, D. E.; Kriegsman, B. A.

    1972-01-01

    The station-keeping guidance system is described, which is designed to automatically keep one orbiting vehicle within a prescribed zone fixed with respect to another orbiting vehicle. The active vehicle, i.e. the one performing the station-keeping maneuvers, is referred to as the shuttle. The other passive orbiting vehicle is denoted as the workshop. The passive vehicle is assumed to be in a low-eccentricity near-earth orbit. The primary navigation sensor considered is a gimballed tracking radar located on board the shuttle. It provides data on relative range and range rate between the two vehicles. Also measured are the shaft and trunnion axes gimbal angles. An inertial measurement unit (IMU) is provided on board the orbiter. The IMU is used at all times to provide an attitude reference for the vehicle. The IMU accelerometers are used periodically to monitor the velocity-correction burns applied to the shuttle during the station-keeping mode. The guidance system is capable of station-keeping the shuttle in any arbitrary position with respect to the workshop by periodically applying velocity-correction pulses to the shuttle.

  18. Designing a Weather Station

    ERIC Educational Resources Information Center

    Roman, Harry T.

    2012-01-01

    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…

  19. Power Station Design

    NASA Technical Reports Server (NTRS)

    1985-01-01

    Kuljian Corporation provides design engineering and construction management services for power generating plants in more than 20 countries. They used WASP (Calculating Water and Steam Properties), a COSMIC program to optimize power station design. This enabled the company to substantially reduce lead time and software cost in a recent design project.

  20. Shippingport Station Decommissioning Project

    Microsoft Academic Search

    McKernan

    1989-01-01

    The Shippingport Atomic Power Station was located on the Ohio River in Shippingport Borough (Beaver County), Pennsylvania, USA. The US Atomic Energy Commission (AEC) constructed the plant in the mid-1950s on a seven and half acre parcel of land leased from Duquesne Light Company (DLC). The purposes were to demonstrate and to develop Pressurized Water Recovery technology and to generate