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1

Ozone profiles above Palmer Station, Antarctica  

NASA Technical Reports Server (NTRS)

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.

Torres, Arnold L.; Brothers, George

1988-01-01

2

Observations of Pc2 waves by Cluster and ground stations in Antarctica  

NASA Astrophysics Data System (ADS)

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.

Liu, Y.

2013-12-01

3

Biodiversity of air-borne microorganisms at Halley station, Antarctica  

Microsoft Academic Search

A study of air-borne microbial biodiversity over an isolated scientific research station on an ice-shelf in continental Antarctica\\u000a was undertaken to establish the potential source of microbial colonists. The study aimed to assess: (1) whether microorganisms\\u000a were likely to have a local (research station) or distant (marine or terrestrial) origin, (2) the effect of changes in sea\\u000a ice extent on

David A. PearceK; K. A. Hughes; T. Lachlan-Cope; S. A. Harangozo; A. E. Jones

2010-01-01

4

Joint US/New Zealand GGOS Station in Antarctica?  

NASA Astrophysics Data System (ADS)

An idea of establishment of a GGOS station in Antarctica to be operated jointly from McMurdo Station (US) and the neighbouring New Zealand's Scott Base is re-examined. Minimal, optimal and maximal scenarios are considered; construction, operation and maintenance costs for different scenarios are discussed. The science case is outlined which includes valuable contribution into study of the Earth orientation parameters, tectonic plate motion, establishment of the Antarctic Vertical Datum, and climate change research.

Gulyaev, S.

2013-12-01

5

VLF wave injection into the magnetosphere from Siple Station, Antarctica  

Microsoft Academic Search

Radio signals in the 1.5- to 16-kHz range transmitted from Siple Station, Antarctica (L = 4), are used to control wave-particle interactions in the magnetosphere. Observations at the conjugate point show signal growth and triggered emissions including risers, failers, and hooks. Growth rates of the order of 100 dB\\/s and total gains up to 30 dB are observed. Triggered emissions

R. A. Helliwell; J. P. Katsufrakis

1974-01-01

6

Chemical composition of fresh snowfalls at Palmer Station, Antarctica  

Microsoft Academic Search

A first time investigation was performed to establish a chemical baseline for snowfall at Palmer Station Antarctica (64°46?S, 64°05?W) since there was no such record. A chemical baseline for snow could be use to validate climate change studies based on ice core analyses. The snow samples contained (from high to low mass concentration) total organic carbon, chloride, inorganic carbon, sodium,

T. P. DeFelice

1998-01-01

7

Alien fly populations established at two Antarctic research stations  

Microsoft Academic Search

The populations of two non-native Dipterans have been established at two Antarctic research stations since at least 1998. Both belong to Sciaridae (“black fungus midge”), and have been determined to the genus Lycoriella. At Rothera Research Station, Antarctic Peninsula, flies are present in the station alcohol bond store, while at Casey Station, on the coast of continental Antarctica, a second

Kevin A. Hughes; Shaun Walsh; Peter Convey; Sarah Richards; Dana M. Bergstrom

2005-01-01

8

Surface and snowdrift sublimation at Princess Elisabeth station, East Antarctica  

NASA Astrophysics Data System (ADS)

In the near-coastal regions of Antarctica, a significant fraction of the snow precipitating onto the surface is removed again through sublimation - either directly from the surface or from drifting snow particles. Meteorological observations from an Automatic Weather Station (AWS) near the Belgian research station Princess Elisabeth in Dronning Maud Land, East-Antarctica, are used to study surface and snowdrift sublimation and to assess their impacts on both the surface mass balance and the surface energy balance. Comparison to three other AWSs in Dronning Maud Land shows that sublimation has a significant influence on the surface mass balance at katabatic locations by removing 10-23 % of their total precipitation, but at the same time reveals anomalously low surface and snowdrift sublimation rates at Princess Elisabeth (18 mm w.e. yr-1 compared to 42 mm w.e. yr-1 at Svea Cross and 52 mm w.e. yr-1 at Wasa/Aboa). This anomaly is attributed to local topography, which shields the station from strong katabatic influence, and therefore on the one hand allows for a strong surface inversion to persist throughout most of the year and on the other hand causes a lower probability of occurrence of intermediately strong winds. These wind speed classes turn out to contribute most to the total snowdrift sublimation mass flux, given their ability to lift a high number of particles while still allowing for considerable undersaturation.

Thiery, W.; Gorodetskaya, I. V.; Bintanja, R.; van Lipzig, N. P. M.; van den Broeke, M. R.; Reijmer, C. H.; Kuipers Munneke, P.

2012-04-01

9

Surface and snowdrift sublimation at Princess Elisabeth station, East Antarctica  

NASA Astrophysics Data System (ADS)

In the near-coastal regions of Antarctica, a significant fraction of the snow precipitating onto the surface is removed again through sublimation - either directly from the surface or from drifting snow particles. Meteorological observations from an Automatic Weather Station (AWS) near the Belgian research station Princess Elisabeth in Dronning Maud Land, East-Antarctica, are used to study surface and snowdrift sublimation and to assess their impacts on both the surface mass balance and the surface energy balance during 2009 and 2010. Comparison to three other AWSs in Dronning Maud Land with 11 to 13 yr of observations shows that sublimation has a significant influence on the surface mass balance at katabatic locations by removing 10-23% of their total precipitation, but at the same time reveals anomalously low surface and snowdrift sublimation rates at Princess Elisabeth (17 mm w.e. yr-1 compared to 42 mm w.e. yr-1 at Svea Cross and 52 mm w.e. yr-1 at Wasa/Aboa). This anomaly is attributed to local topography, which shields the station from strong katabatic influence, and, therefore, on the one hand allows for a strong surface inversion to persist throughout most of the year and on the other hand causes a lower probability of occurrence of intermediately strong winds. This wind speed class turns out to contribute most to the total snowdrift sublimation mass flux, given its ability to lift a high number of particles while still allowing for considerable undersaturation.

Thiery, W.; Gorodetskaya, I. V.; Bintanja, R.; Van Lipzig, N. P. M.; Van den Broeke, M. R.; Reijmer, C. H.; Kuipers Munneke, P.

2012-08-01

10

Chemical composition of fresh snowfalls at Palmer Station, Antarctica  

NASA Astrophysics Data System (ADS)

A first time investigation was performed to establish a chemical baseline for snowfall at Palmer Station Antarctica (64°46'S, 64°05'W) since there was no such record. A chemical baseline for snow could be use to validate climate change studies based on ice core analyses. The snow samples contained (from high to low mass concentration) total organic carbon, chloride, inorganic carbon, sodium, sulfate, magnesium, calcium, potassium, fluoride, ammonium, and nitrate, excluding hydrogen and hydroxide. The pH of these samples ranged between 4.0-6.2. The relatively low nitrate and relatively high sulfate concentrations found in our samples are consistent with the results of other studies for this region of Antarctica. The ions and pH do not appear to favor a particular wind direction during this period. The total deposition of sulfate and flouride via snowfall between 10 January and 10 February is conservatively estimated to be 4.78 and 1.3 kg km -2, respectively.

DeFelice, T. P.

11

Record low ozone measured at McMurdo Station, Antarctica, during the austral spring of 1993  

SciTech Connect

The annual springtime ozone hole over Antarctica has been studied extensively since it was first reported. The University of Wyoming has participated in monitoring the development of the ozone hole over Antarctica since 1986 using balloonborne instruments to measure vertical profiles of ozone and particles at McMurdo Station, Antarctica. During austral spring 1993, record minimums in total column ozone were observed along with a record low within the main ozone layer at 12-20 kilometers (km). 6 refs., 2 figs.

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

1994-12-31

12

Antarctica  

Atmospheric Science Data Center

article title:  Twilight in Antarctica     View larger JPEG image  (51 kb) Twilight in Antarctica, February 24, 2000 . Nearly 15 times every 24 hours, the Terra ... - The Ross Ice Shelf and the Transantarctic Mountains of Antarctica at twilight. project:  MISR category:  ...

2013-04-16

13

Deployment of Autonomous GPS Stations in Marie Byrd Land, Antarctica  

NASA Technical Reports Server (NTRS)

During the 1998-1999 Antarctic field season, we installed three autonomous GPS stations in Marie Byrd Land, West Antarctica to measure glacio-isostatic rebound and rates of spreading across the West Antarctic Rift System. The systems collect data throughout the entire year and therefore must function during the warm, relatively mild summer, and cold, harsh winters. They are powered by gel cell batteries that are charged by wind and solar power. The system includes dual data logging capability. We log data at 5 minute intervals within the receiver and at 30 second intervals to a serial data logger. We do not require 365 days of continuous data for well determined crustal velocities, but rather long periods (greater than 24 hours) of continuous data distributed throughout the year. Therefore, for simplicity, we designed the system to accept occasional data interruptions. The batteries, in addition to supplying power, act as a thermal capacitive heat storage device to help regulate the temperatures within the system. This storage system absorbs the majority of the 10-15 watts of power from the receiver and 5 watts from the data logger which helps to maintain temperature for long periods of time. Power is switched off when the temperature within the system enclosure reaches 50'C and is reconnected at 20 C. If battery voltage drops too low the batteries will freeze. Therefore, we cut the power off when the batteries drop to a low voltage of 12.45V. Power is restored at 13.2V. The temperature and power hysteresis allows for a minimum of several days of data to be collected before system shutdowns. A check of all three stations in late January 1999 indicated that the thermal and power control systems are performing as expected. We plan to implement satellite telemetry to the systems during the 2000-2001 season following a year of development.

Donnellan, Andrea; Luyendyk, Bruce; Rebold, Thomas; Awaya, Henry; Nesbit, William; Dace, Gregory

1999-01-01

14

Observations of Earth space by self-powered stations in Antarctica S. B. Mende,1  

E-print Network

Observations of Earth space by self-powered stations in Antarctica S. B. Mende,1 W. Rachelson,1 R. Engebretson,4 U. Inan,5 J. W. Labelle,6 L. J. Lanzerotti,7 and A. T. Weatherwax8 1 Space Science Laboratory the high latitude regions, and there are distinct advantages in making remote sensing observations

California at Berkeley, University of

15

Antarctica  

NSDL National Science Digital Library

A variety of classroom activities and lessons on Antarctica from the Gulf of Maine Aquarium, including: Coping with the Cold, Blubber Glove, Salt Concentration, Penguin Adaptation, Chick Die-Off, Changes in Antarctic Ice, and Creating Plankton. Discover how penguins are the "litmus paper of the sea," see satellite imagery of the changing ice formations around Antarctica, and learn how animals can survive in sub-freezing water. Links to other Aquarium modules.

16

Tidal gravity variations revisited at Vostok Station, Antarctica  

NASA Astrophysics Data System (ADS)

In 1969, prior to the discovery of the subglacial Lake Vostok, an Askania Gs-11 gravimeter was operated at Vostok Station (78.466°S, 106.832°E; 3478 m asl) to observe tidal gravity variations. To gain a better understanding of the lake's tidal dynamics, we reanalyzed these data using a Bayesian Tidal Analysis Program Grouping method (BAYTAP-G and -L programs). The obtained phase leads for the semidiurnal waves M2 (6.6 ± 2.1°) and S2 (10.1 ± 4.2°) are more pronounced than those of the diurnal waves, among which the largest phase lead (for K1) was 5.0 ± 0.5°. The obtained ? factor for M2 was 0.890 ± 0.032, significantly less than the theoretical value of 1.16. For three global ocean tide models (NAO99b, FES2004, and TPXO6.2), the estimated load tides on waves Q1, O1, P1, K1, M2, and S2 range from 0.1-0.2 ?Gal (Q1 and S2) to 0.6-0.7 ?Gal (K1). The difference in amplitude among the three models is less than 0.14 ?Gal (M2), and the difference in phase is generally less than 10°. In calculating the residual tide vectors using the ocean models, the TPXO6.2 model generally gave the smallest residual amplitudes. Our result for the K1 wave was anomalously large (1.36 ± 0.25 ?Gal), while that for the M2 wave was sufficiently small (0.37 ± 0.17 ?Gal). The associated uncertainty is half that reported in previous studies. It is interesting that the residual K1 tide is approximately 90° phase-leaded, while the M2 tide is approximately 180° phase-leaded (delayed). Importantly, a similar reanalysis of data collected at Asuka Station (71.5°S, 24.1°E) gave residual tides within 0.2-0.3 ?Gal for all major diurnal and semidiurnal waves, including the K1 wave. Therefore, the anomalous K1 residual tide observed at Vostok Station must be linked to the existence of the subglacial lake and the nature of solid-ice-water dynamics in the region.

Doi, Koichiro; Shibuya, Kazuo; Wendt, Anja; Dietrich, Reinhard; King, Matt

17

Antarctica  

NSDL National Science Digital Library

This lesson plan is part of the DiscoverySchool.com lesson plan library for grades 6-8. It focuses on icebergs and water salinity, as well as the environment of the continent of Antarctica. Students research this area and do an experiment demonstrating the relationship between water salinity and ice floating or sinking in the ocean. Included are objectives, materials, procedures, discussion questions, evaluation ideas, suggested readings, and vocabulary. There are videos available to order which complement this lesson, an audio-enhanced vocabulary list, and links to teaching tools for making custom quizzes, worksheets, puzzles and lesson plans.

Mary Cahill

18

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

NASA Technical Reports Server (NTRS)

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.

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

19

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

NASA Astrophysics Data System (ADS)

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.

Fossat, E.

2002-06-01

20

Halogen oxides from MAXDOAS observations at Belgrano station (Antarctica, 78ºS) in 2013  

NASA Astrophysics Data System (ADS)

BrO and IO play an important role in the tropospheric distribution of ozone. Tropospheric distribution of both radicals in Antarctica is still an open issue since there are some uncertainties over both its geographical and vertical distribution. Accurate MAXDOAS measurements of both components are important to set the their vertical distribution and to understand the halogen chemistry in the troposphere in Antarctica, where BrO and IO ground based measurements are very sparse and satellite observations have some limitations. In February 2011 a Multiaxis Differential Optical Absorption Spectroscopy (MAX- DOAS) instrument was installed at Belgrano II station (Antarctica) to have a better understanding of BrO distribution in this site and to improve the Antarctic program INTA has been performing from 1994 for stratospheric ozone monitoring and research. In this same framework in February 2013, a second MAXDOAS spectrometer started to measure IO continuosly. Both instruments have been entirely developed at INTA including the detector read-out electronics and have been been robustly designed for continuous operation in rough environment like Antarctica. Belgrano station is a candidate to be a NDACC site for continuous monitoring of atmospheric composition. Within the framework of NORS project NDACC expertise is being exported to MAXDOAS observations carried out in this station. In this work IO and BrO MAXDOAS DSCD between 2º and 90º elevation angles are presented from February to early April and from September to October 2013. Tropospheric IO is detected almost every day of measurement above the detection limit and the seasonal evolution show a good agreement with previous works as Saiz-Lopez et al., 2007, with higher columns towards the end of February, early March. The observed behaviour during the spring is, however, highly variable. Tropospheric BrO is as well detected during the whole period of measurements above detection limit with columns increasing towards the end of the period. During spring the column is, as in the case of IO, highly variable with some strong and sudden enhancements episodes during the month of September and October.

Puentedura, Olga; Yela, Margarita; Gil, Manuel; Perez-Camacho, Manuel; Navarro-Comas, Monica; Ochoa, Hector

2014-05-01

21

Ground-based measurements of column amounts of NO{sub 2} over Syowa Station, Antarctica  

SciTech Connect

The authors interpret column measurements of NO{sub 2} made from Syowa Station, Antarctica since March, 1990. It is lowest in midwinter, and peaks in midsummer. The fall rate of decrease is considerably greater than the spring increase rate. Temperature trends indicate that late winter polar stratospheric clouds could form, providing an explanation for low NO{sub 2} abundances. They have used a box model to simulate the observed density variations. Increasing amounts of aerosols from the eruption of Pinatubo probably account for lower NO{sub 2} densities in late spring of 1991. Effects due to the atmospheric aerosol loading are seen to extend into 1992, and also during 1992 the vortex boundary was located differently with respect to the observation station.

Kondo, Y.; Hayashi, M.; Nakajima, H.; Tsukui, K. [Nagoya Univ., Toyokawa (Japan)] [Nagoya Univ., Toyokawa (Japan); Matthews, W.A. [National Institute of Water and Atmospheric Research, Lauder (New Zealand)] [National Institute of Water and Atmospheric Research, Lauder (New Zealand); Solomon, S. [National Oceanic and Atmospheric Administration, Boulder, CO (United States)] [National Oceanic and Atmospheric Administration, Boulder, CO (United States); Yamazaki, K. [Meteorological Research Institute, Tsukuba (Japan)] [Meteorological Research Institute, Tsukuba (Japan)

1994-07-20

22

The 1994 to 2008 concentration variations of atmospheric CO2 observed at Jubany Station (Antarctica)  

NASA Astrophysics Data System (ADS)

Since 1994 the Italian PNRA (National Research Program in Antarctica) and the Argentina DNA (Direction National de Antartico) have been collecting continuous atmospheric carbon dioxide measurements at Jubany. The Antarctic station at Jubany (62° 14'S, 58° 40'W) is located in King George Island, in the South Shetland archipelago, north of the Antarctic Peninsula. The laboratory is situated at an elevation of 15 m.s.l. on the SE slope of Potter Bay. The measurements are taken by using a Siemens U5 analyzer based on NDIR (Non Dispersive InfraRed) absorption method. Details are given on the station environment, meteorological conditions, instrumentation, and data selection strategy. The paper presents the first 14 years (1994-2008) of continuous atmospheric CO2 measurements; the interannual and seasonal variations of CO2 data are described

Gallo, Veronica; de Simone, Sara; Ciattaglia, Luigi; Rafanelli, Claudio; Diego, Piero

2010-05-01

23

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

NASA Astrophysics Data System (ADS)

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

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

2009-12-01

24

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

SciTech Connect

The authors present here a case study of cloud-mediated production of cloud condensation nuclei (CCN) recorded at Palmer Station (64{degrees}46`S, 64{degrees}05`W), Antarctica on 20 Jan 1994. Four instances of CCN bursts occured on January 17, 19, 20 and February 7, 1994 when cloud base descended to the surface and dissipated under prevailing meteorlogical conditions. The most spectacular event ocurred on January 20 when the CCN concentration was enhanced by a factor of four at 0.025% supersaturation (with respect to water) compared to the prevent concentration. At 1.25% supersaturation, the corresponding enhancement was by a factor of seven. This indicated a larger production of aerosol particles in smaller size ranges. The elevated CCN concentrations were measured for over fifteen hours. The CCN activity spectrum during the event resembled the ones that are typical of previous measurements in the urban plumes of St. Louis and Denver. 30 refs., 3 figs.

Saxena, V.K. [North Carolina State Univ., Raleigh, NC (United States)] [North Carolina State Univ., Raleigh, NC (United States)

1996-01-01

25

FY 1994 ambient air monitoring report for McMurdo Station, Antarctica  

SciTech Connect

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.

Lugar, R.M.

1994-12-01

26

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

SciTech Connect

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

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

1990-02-01

27

Results of monitoring for PCDDs and PCDFs in ambient air at McMurdo Station, Antarctica  

SciTech Connect

This report presents the results of ambient air monitoring for polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) performed during the 1992-1993 austral summer in the vicinity of McMurdo Station, Antarctica. Fifteen air samples were collected from four different locations for determination of the presence and concentration of PCDD/PCDF compounds. General Metal Works Inc. PS-1 air samplers equipped with polyurethane foam (PUF) with a sample flow rate of approximately 0.27 m{sup 3}/min. were used to collect air samples. Sampling site selection, sampling procedures, and quality assurance procedures used were consistent with U.S. Environmental Protection Agency guidance for local ambient air quality networks. PCDD/PCDF compounds were not detected at the predominantly upwind location and at a more remote site on Black Island. Trace levels of only a few PCDD/PCDF congeners were detected sporadically at a location approximately 500 meters downwind of the station. The most frequent, most varied, and highest levels of PCDDs/PCDFs were measured at a {open_quotes}downtown{close_quotes} location, where concentrations of total PCDDs ranged from 0.27 to 1.80 pg/m{sup 3} and total PCDFs from less than 0.1 to 2.77 pg/m{sup 3}. Results from the remote Black Island site indicate that the background Antarctic air is still {open_quotes}free{close_quotes} of PCDD/PCDF compounds (not detectable at current method detection limits). The initial baseline effort demonstrated that site selection and sampling equipment performance were satisfactory, provided useful data for assessing the impact of McMurdo operations on the local ambient air quality, and provided baseline data for assessing the Antarctica continental air quality.

Lugar, R.M.

1993-09-01

28

Influence of the optically-active turbulence on astronomical seeing at Concordia station - Dome C, Antarctica  

NASA Astrophysics Data System (ADS)

The study of the distorting action of the atmospheric turbulence is important to understand the reason of the astronomical seeing variability, and to propose reliable methods to estimate the seeing quality. The influence of the atmospheric surface layer thermal turbulence on distortion of astronomical images is investigated. During a campaign carried out at Concordia station at Dome C, East Antarctica in winter 2012, an experiment was carried out to determine the behaviour and the contribution of the optically-active atmospheric turbulence in the lowest tens meters. The surface layer in the interior of Antarctica during winter is extremely stably stratified with the difference of temperature between the surface and the top of the inversion reaching 30-40 °C. Direct optical measurements of the seeing made by differential image motion monitors (DIMM) at two levels, 8 and 20 m, were made simultaneously with turbulence observations in the near-surface atmospheric layer. The intensity of the thermal turbulence was detected and evaluated using both a specially designed high-resolution sodar, and sonic anemometer measurements. The statistics of some meteorological variables, including long-wave downwelling radiation, characterising the presence of cloudiness are obtained. Typical patterns of the turbulence shown by sodargrams are analysed and classified. The statistics of the heights of the surface-based turbulent layer and of the seeing quality values are presented. A correlation exists between the seeing quality and the intensity of turbulence measured by sodar. Statistics of turbulent optical factor (TOF) for different layers within the surface layer are analysed for the total period and for clear sky conditions to give recommendations on how to choose an optimal height for the installation of the astronomical instrumentation.

Petenko, Igor; Aristidi, Eric; Agabi, Karim; Bouchez, Guillaume; Bondoux, Erick; Pietroni, Ilaria; Argentini, Stefania; Viola, Angelo; Casasanta, Giampietro; Mastrantonio, Giangiuseppe

2013-04-01

29

Antibiotic resistance among bacteria isolated from seawater and penguin fecal samples collected near Palmer Station, Antarctica.  

PubMed

Antibiotic resistance in aquatic bacteria has increased steadily as a consequence of the widespread use of antibiotics, but practice and international treaty should have limited antibiotic contamination in Antarctica. We estimated antibiotic resistance in microorganisms isolated from the Antarctic marine waters and a penguin rookery, for 2 reasons: (i) as a measure of human impact and (ii) as a potential "snapshot" of the preantibiotic world. Samples were taken at 4 established sampling sites near Palmer Station, which is situated at the southern end of the Palmer Archipelago (64 degrees 10'S, 61 degrees 50'W). Sites were chosen to provide different potentials for human contamination. Forty 50 mL samples of seawater were collected and colony-forming units (CFU)/mL were determined at 6 and 20 degrees C. For this study, presumed psychrophiles (growth at 6 degrees C) were assumed to be native to Antarctic waters, whereas presumed mesophiles (growth at 20 degrees C but not at 6 degrees C) were taken to represent introduced organisms. The 20-6 degrees C CFU/mL ratio was used as a measure of the relative impact to the ecosystem of presumably introduced organisms. This ratio was highest at the site nearest to Palmer Station and decreased with distance from it, suggesting that human presence has impacted the natural microbial flora of the site. The frequency of resistance to 5 common antibiotics was determined in each group of isolates. Overall drug resistance was higher among the presumed mesophiles than the presumed psychrophiles and increased with proximity to Palmer Station, with the presumed mesophiles showing higher frequencies of single and multiple drug resistance than the psychrophile population. The frequency of multidrug resistance followed the same pattern. It appears that multidrug resistance is low among native Antarctic bacteria but is increased by human habitation. PMID:19190699

Miller, Robert V; Gammon, Katharine; Day, Martin J

2009-01-01

30

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

NASA Technical Reports Server (NTRS)

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.

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

2006-01-01

31

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

PubMed

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

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

2001-10-01

32

Ozone profiles at McMurdo Station, Antarctica during the austral spring of 1992  

SciTech Connect

Thirty-seven vertical profiles of ozone and temperature were measured at McMurdo Station, Antarctica (78[degrees]S) from 23 August to 31 October 1992. Total column ozone dropped from an initial 223 Dobson Units (DU) on 24 August to 158 DU on 27 September. The 12-20 km column reached a record low of 17 DU on 9 October, an 84% loss compared to the initial value of 106 DU. The most severely depleted layer was between 12 and 15 km which coincided with the volcanic aerosol layer (11-16 km) observed by aerosol counter flights and the Italian Lidar at McMurdo. By the end of September the polar vortex elongated and shifted away from McMurdo. Subsequent profiles, above 20 km altitude, were typically 15-20[degrees]C warmer and ozone concentrations were 50-100% higher for the remainder of the measurement period. The 12-16 km layer, however, remained 80 to 97% depleted compared to the initial profile. 9 refs., 5 figs.

Johnson, B.J.; Deshler, T.; Rozier, W.R. (Univ. of Wyoming, Laramie, WY (United States))

1994-02-15

33

Stratospheric ClO profiles from McMurdo Station, Antarctica, spring 1992  

SciTech Connect

The authors 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 NO{sub 2}. 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. 20 refs., 7 figs., 2 tabs.

Emmons, L.K.; Shindell, D.T.; Reeves, J.M. [State Univ. of New York, Stony Brook, NY (United States)] [and others] [State Univ. of New York, Stony Brook, NY (United States); and others

1995-02-20

34

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

SciTech Connect

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.

Lugar, R.M.

1993-05-01

35

Ocean current observations near McMurdo Station, Antarctica, 1993 to 1994: Relation to wastewater discharge dispersal  

SciTech Connect

This report presents analyses of current measurements from McMurdo Sound, Antarctica during December, 1993 to November, 1994, in relation to dispersal of the McMurdo Station wastewater plume. Data collected from 1991 to 1993 are also discussed here. Six current meters were deployed near McMurdo Station, Antarctica, from December 1993 to November 1994. Five functioned properly throughout the observation period, and one failed. Analyses of 5 data series include: (1) summaries of current speed and direction, (2) directional analyses of flow, (3) time series current vectors averaged over 1, 3, 6, 12, and 24 h, (4) principal axes of flow, (5) maps of mean seasonal flow, (6) progressive vector plots, (7) spectral analyses, and (8) low-pass filtered (30h) time series of currents at McMurdo Station. Observations of flow near McMurdo Station during 1994 were generally similar to 1993. Short term variation in flow was related principally to diurnal tidal motions. Longer period oscillations in flow such as seasonal shifts, and non-periodic changes in current speed and direction were likely related to changes in ice cover and wind stress in the vicinity of McMurdo Station or over much larger scales or both. Three distinct oceanographic {open_quote}seasons{close_quote} were apparent in time series from 1992 to 1994, from stations furthest offshore, where the effects of local topography are minimal. The spring-summer (Oct.-Jan.) period of both years was dominated by regional southward flow, which generates a counter-clockwise eddy (McMurdo Gyre) adjacent to McMurdo Station. With regard to dispersal of the wastewater plume from McMurdo Station, observations of currents during 1994 generally corroborate those from 1993, and the recommendation that the outfall pipe should be repositioned offshore of the McMurdo Gyre is supported.

Barry, J.P. [J.P. Barry Consulting, Monterey, CA (United States)

1995-09-01

36

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

PubMed

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

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

2014-10-15

37

Sea-ice thickness and mass at Ice Station Belgica, Bellingshausen Sea, Antarctica  

NASA Astrophysics Data System (ADS)

Ice Station Belgica was commenced in late winter 2007 in the Bellingshausen Sea as part of Sea Ice Mass Balance in Antarctica (SIMBA), an IPY 2007 cruise on the research vessel N.B. Palmer. A primary objective was to build on the work of previous Antarctic drift station experiments to geophysically characterize sea ice in terms of thickness, surface and ice bottom morphology, and ultimately area-unitized mass. A 24 day drift station was established at approximately 70°S and 93°W in mixed first-year and multi-year ice with three geophysical study sites selected on a 5 km 2 floe. A comprehensive time series assessment of elevation-surveyed transects ranging from 100 m to 300 m in length included snow surface elevation, snow depth, electromagnetic (EM) profiling, and direct drilling for ice draft and ice freeboard. Additional work included a snow surface morphology characterization of a 100 m×300 m area between the primary time series EM transects. Correlation of EM ice thicknesses with collocated drilled ice thickness yielded equations for the correction of EM underestimation of thick deformed ice, particularly at pressure ridges. Mean ice thickness from corrected EM was compared to isostatic ice thickness calculated from surface elevation, snow depth, ice freeboard and respective snow, slush, ice, and sea water densities. Results were consistent, with mean ice thicknesses for multi-year ice of 2.35 m, 2.34 m, and 2.41 m, with similar variance, for corrected EM, drilling, and buoyancy methods respectively. Additionally, a mean ice thickness of 2.31 m was calculated from ASPeCt observations of the ice field associated with the floe, using the method incorporating mean sail heights and fractional coverage of surface deformities or ridging. Temporal series assessment of ice freeboard indicated a slightly negative mean ice freeboard (<0.04 m), with clear evidence of new snow-ice formation from the freezing of slush. The three distinct snow and ice regions assessed on the Belgica floe had mean corrected EM ice thickness of 0.52±0.04 m (±1 std. deviation), 0.92±0.17 m, and 2.35±1.37 m, and mean snow depths of 0.08±0.03 m, 0.36±0.09 m, and 0.68±0.31 m respectively. Each ice type represented a sizable fraction of the floe's total area (˜20%, 40%, and 40% respectively from visual estimates) reflecting a complex dynamic and thermodynamic history of formation, as well as the difficulty in characterizing even a single floe by a single class or mean value for thickness and snow depth. Implications of these results are discussed with regards to the resolution of satellite-based altimetry and snow depth products and efforts to generate and validate satellite sea ice and snow thickness products.

Weissling, B. P.; Lewis, M. J.; Ackley, S. F.

2011-05-01

38

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

SciTech Connect

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.

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

2014-09-01

39

Quantifying and Improving DNS Availability Casey Deccio  

E-print Network

Quantifying and Improving DNS Availability By Casey Deccio B.S. (Brigham Young University) 2002 M;Copyright by CASEY DECCIO 2010 #12;Abstract Quantifying and Improving DNS Availability by Casey Deccio The Domain Name System (DNS) is one of the components most critical to Internet functionality. Nearly all

California at Davis, University of

40

Ocean current observations near McMurdo Station, Antarctica from 1991 to 1993: Relation to wastewater discharge dispersal  

SciTech Connect

Analyses of ocean currents in the vicinity of McMurdo Station, Antarctica, are relevant to the transport and dispersal of wastewater from the McMurdo Station sewage outfall pipe. Observations of ocean currents during the initial phases of this study have been presented by Howington and McFeters. These studies, using coliform bacterial counts as an indicator of dispersion of the wastewater plume and current meters to measure flow patterns, indicated that dispersal of the plume by local currents does not effectively remove the plume from the vicinity of McMurdo Sound, under the present outfall pipe location. Moreover, these studies suggest that, although the flow pattern is generally consistent with transport of the plume away from McMurdo Station, episodes of current reversal are sufficient to transport the wastewater plume along the shore toward the southeast, eventually overlapping the seawater intake area near the McMurdo jetty. Several concerns included (a) impacts of wastewater inputs to nearshore benthic and pelagic habitats adjacent to McMurdo Station, (b) effects of wastewater input to the McMurdo Station fresh water intake source, and (c) reduction in human impacts on the McMurdo Sound ecosystem. These concerns motivated studies to characterize nearshore currents more extensively in relation to dispersal of the wastewater plume. This report discusses analysis results of current observations from November 1992 to November 1993.

Barry, J.P. [J. P. Consulting, Monterey, CA (United States)

1994-08-01

41

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

Microsoft Academic Search

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

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

1989-01-01

42

Daily variation at Concordia station (Antarctica) and its dependence on IMF conditions  

Microsoft Academic Search

After some short test surveys, during the 2004-2005 summer expedition in Antarctica, a geomagnetic French-Italian observatory was installed on the plateau (geographic coordinates: 75.1° S, 123.4° E; corrected geomagnetic coordinates: 88.9° S, 54.3° E; UT=LT-8) very close to the geomagnetic pole. In this paper we present some peculiarities of the daily variation as observed at this polar cap observatory during

L. Cafarella; D. di Mauro; S. Lepidi; A. Meloni; M. Pietrolungo; L. Santarelli; J. J. Schott

2007-01-01

43

Health and safety plan for the preliminary site investigation for McMurdo Station, Ross Island, Antarctica  

SciTech Connect

The primary purpose of this health and safety plan is to provide the Argonne National Laboratory (ANL) field team with important procedures, regulations, and requirements necessary for performing work at McMurdo Station, Antarctica, with a minimum hazard to its health and safety. Field workers will be required to conduct their operations in a safe environment through specific safety and occupational health procedures. The plan assigns responsibilities and provides for contingencies that may arise at the site. The health and safety plan will also demonstrate to the National Science Foundation (NSF), the US Department of Energy (DOE), the US Environmental Protection Agency (EPA), the US Occupational Safety and Health Administration (OSHA), environmental interest groups, and other countries represented in Antarctica that the health and safety of ANL personnel have been given the utmost consideration in planning the work operations, applicable rules and regulations of the area have been met, and the health and safety of the public and the environment have been given significant consideration during field sampling activities. This document represents the final health and safety plan for the preliminary site investigation. A draft version of this report was presented to NSF in January 1991. 16 refs., 3 figs., 8 tabs.

Wozny, M.C.

1991-05-01

44

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

NASA Astrophysics Data System (ADS)

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

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

2012-07-01

45

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

NASA Astrophysics Data System (ADS)

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

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

2003-03-01

46

WBUR Journeys to Antarctica  

NSDL National Science Digital Library

This is the record of an environmental reporter's expedition to Antarctica. During his time in Antarctica, the author wrote reports and captured photos, video and audio of the animals, the environment and the people who live there. Topics include wildlife and how it has been affected by climate change, equipment needed for working in Antarctica, and life at Palmer Station. A series of journal entries by the author give an account of what it was like to travel, work, and live in Antarctica. An extensive collection of multimedia materials includes photos, videos, and an interactive tour of Palmer Station.

47

Results of monitoring for polychlorinated dibenzo-p-dioxins and dibenzofurans in ambient air at McMurdo station, Antarctica  

SciTech Connect

This paper presents the results of ambient air monitoring for polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) performed during the 1992-1993 and 1993-1994 austral summers in the vicinity of McMurdo Station, Antarctica. Twenty-eight air samples were collected from four different locations to determine the identity and concentration of PCDD/PCDF compounds. PCDD/PCDF compounds were not detected at either the predominantly upwind location or a more remote site on Black Island. Trace levels of only a few PCDD/PCDF congeners were detected sporadically at a location approximately 500 m downwind of the station. The most frequent, most varied, and highest levels of PCDDs/PCDFs were measured at a `downtown` location, where concentrations of total PCDDs ranged from 0.12 to 1.80 pg/m{sup 3} and total PCDDs ranged from less than 0.02 to 2.77 pg/m{sup 3}. The data indicate that there are combustion sources at McMurdo other than the solid waste incinerator (power plants, vehicles, heating furnaces, etc.) that contribute PCDD/PCDF compounds to the ambient air. The greatest variety and highest concentration of PCDD/PCDF congeners measured in 1992-1993 during incineration of selected solid wastes implicates the interim incinerator as the likely source of the increased presence of these compounds in air. 18 refs., 2 figs., 3 tabs.

Lugar, R.M. [ERM-Program Management Co., Idaho Falls, ID (United States)] [ERM-Program Management Co., Idaho Falls, ID (United States); Harles, R.L. [EPA/AREAL, Research Triangle Park, NC (United States)] [EPA/AREAL, Research Triangle Park, NC (United States); Dupuy, A.E.; McDaniel, D.D. [EPA/OPPTS/OPP/BEAD/ACB, Stennis Space Center, MS (United States)] [EPA/OPPTS/OPP/BEAD/ACB, Stennis Space Center, MS (United States)

1996-02-01

48

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

NASA Astrophysics Data System (ADS)

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

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

2006-12-01

49

Propagation of low frequency geomagnetic field fluctuations in Antarctica: comparison between two polar cap stations  

Microsoft Academic Search

We conduct a statistical analysis of the coherence and phase difference of low frequency geomagnetic fluctuations between two Antarctic stations, Mario Zucchelli Station (geographic coordinates: 74.7° S, 164.1° E; corrected geomagnetic coordinates: 80.0° S, 307.7° E) and Scott Base (geographic coordinates: 77.8° S 166.8° E; corrected geomagnetic coordinates: 80.0° S 326.5° E), both located in the polar cap. Due to

L. Santarelli; S. Lepidi; L. Cafarella

2007-01-01

50

Daily variation at Concordia station (Antarctica) and its dependence on IMF conditions  

NASA Astrophysics Data System (ADS)

After some short test surveys, during the 2004-2005 summer expedition in Antarctica, a geomagnetic French-Italian observatory was installed on the plateau (geographic coordinates: 75.1° S, 123.4° E; corrected geomagnetic coordinates: 88.9° S, 54.3° E; UT=LT-8) very close to the geomagnetic pole. In this paper we present some peculiarities of the daily variation as observed at this polar cap observatory during the years 2005 and 2006, taking into account the different Loyd seasons and different interplanetary magnetic field conditions. Some interesting results emerge from the analysis, confirming the dependence of the daily variation (and of the associated polar current systems) on the IMF Bz and By components. In particular the analysis showed that different Bz conditions correspond to different contribution to daily variation of ionospheric and field aligned currents, while particular By conditions lead to a time shift of the diurnal variation, indicating an asymmetry with respect to the noon meridian.

Cafarella, L.; di Mauro, D.; Lepidi, S.; Meloni, A.; Pietrolungo, M.; Santarelli, L.; Schott, J. J.

2007-10-01

51

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

NASA Astrophysics Data System (ADS)

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

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

2005-07-01

52

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

NASA Astrophysics Data System (ADS)

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

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

2005-11-01

53

Long-term monitoring of persistent organic pollutants (POPs) at the Norwegian Troll station in Dronning Maud Land, Antarctica  

NASA Astrophysics Data System (ADS)

A first long-term monitoring of selected persistent organic pollutants (POPs) in Antarctic air has been conducted at the Norwegian research station Troll (Dronning Maud Land). As target contaminants 32 PCB congeners, ?- and ?-hexachlorocyclohexane (HCH), trans- and cis-chlordane, trans- and cis-nonachlor, p,p'- and o,p-DDT, DDD, DDE as well as hexachlorobenzene (HCB) were selected. The monitoring program with weekly samples taken during the period 2007-2010 was coordinated with the parallel program at the Norwegian Arctic monitoring site (Zeppelin mountain, Ny-Ålesund, Svalbard) in terms of priority compounds, sampling schedule as well as analytical methods. The POP concentration levels found in Antarctica were considerably lower than Arctic atmospheric background concentrations. Similar to observations for Arctic samples, HCB is the predominant POP compound, with levels of around 22 pg m-3 throughout the entire monitoring period. In general, the following concentration distribution was found for the Troll samples analyzed: HCB > Sum HCH > Sum PCB > Sum DDT > Sum chlordanes. Atmospheric long-range transport was identified as a major contamination source for POPs in Antarctic environments. Several long-range transport events with elevated levels of pesticides and/or compounds with industrial sources were identified based on retroplume calculations with a Lagrangian particle dispersion model (FLEXPART).

Kallenborn, R.; Breivik, K.; Eckhardt, S.; Lunder, C. R.; Manø, S.; Schlabach, M.; Stohl, A.

2013-07-01

54

Long-term monitoring of persistent organic pollutants (POPs) at the Norwegian Troll station in Dronning Maud Land, Antarctica  

NASA Astrophysics Data System (ADS)

A first long-term monitoring of selected persistent organic pollutants (POPs) in Antarctic air has been conducted at the Norwegian Research station Troll (Dronning Maud Land). As target contaminants 32 PCB congeners, a- and g-hexachlorocyclohexane (HCH), trans- and cis-chlordane, trans- and cis-nonachlor, p,p'- and o,p-DDT, DDD, DDE as well as hexachlorobenzene (HCB) were selected. The monitoring program with weekly samples taken during the period 2007-2010 was coordinated with the parallel program at the Norwegian Arctic monitoring site (Zeppelin mountain, Ny-Ålesund, Svalbard) in terms of priority compounds, sampling schedule as well as analytical methods. The POP concentration levels found in Antarctica were considerably lower than Arctic atmospheric background concentrations. Similar as observed for Arctic samples, HCB is the predominant POP compound with levels of around 22 pg m-3 throughout the entire monitoring period. In general, the following concentration distribution was found for the Troll samples analyzed: HCB > Sum HCH > Sum PCB > Sum DDT > Sum chlordanes. Atmospheric long-range transport was identified as a major contamination source for POPs in Antarctic environments. Several long-range transport events with elevated levels of pesticides and/or compounds with industrial sources were identified based on retroplume calculations with a Lagrangian particle dispersion model (FLEXPART). The POP levels determined in Troll air were compared with 1 concentrations found in earlier measurement campaigns at other Antarctic research stations from the past 18 yr. Except for HCB for which similar concentration distributions were observed in all sampling campaigns, concentrations in the recent Troll samples were lower than in samples collected during the early 1990s. These concentration reductions are obviously a direct consequence of international regulations restricting the usage of POP-like chemicals on a worldwide scale.

Kallenborn, R.; Breivik, K.; Eckhardt, S.; Lunder, C. R.; Manø, S.; Schlabach, M.; Stohl, A.

2013-03-01

55

Observations of Earth space by self-powered stations in Antarctica  

NASA Astrophysics Data System (ADS)

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

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

2009-12-01

56

GARS O'Higgins as a core station for geodesy in Antarctica  

NASA Astrophysics Data System (ADS)

The German Antarctic Receiving Station GARS O'Higgins at the northern tip of the Antarctic Peninsula is a dual purpose facility for Earth observation since more than 20 years. It serves as a satellite ground station for payload data downlink and telecommanding of remote sensing satellites as well as a geodetic observatory for global reference frames and global change. Both applications use the same 9m diameter radio telescope. For space geodesy and astrometry the radio telescope significantly improves the coverage on the southern hemisphere and plays an essential role within the global Very Long Baseline Interferometry (VLBI) network. In particular the determination of the Earth Orientation Parameters (EOP) and the sky coverage of the International Celectial Reference Frame (ICRF) benefit from the location at high southern latitude. Further geodetic instrumentation includes different permanent GNSS receivers (since 1995), two SAR corner reflectors (since 2013) and in the past a PRARE system (1996 - 2004). In addition absolute gravity measurements were performed in 1997 and 2011. All geodetic reference points are tied together by a local survey network. The various geodetic instrumentation and the long time series at O'Higgins allow a reliable determination of crustal motions. VLBI station velocities, continuous GNSS time series and absolute gravity measurements consistently document an uplift rate of about 5 mm/a. A pressure gauge and a radar tide gauge being refererenced to space by a GNSS antenna on top allow the measurement of sea level changes independently from crustal motions, and the determination of the ellipsoidal height of the sea surface, which is, the geoid height plus the mean dynamic topography. The outstanding location on the Antarctic continent makes GARS O'Higgins also in future attractive for polar orbiting satellite missions and an essential station for the global VLBI network. Future plans envisage a development towards an observatory for environmentally relevant research.

Klügel, Thomas; Diedrich, Erhard; Falk, Reinhard; Hessels, Uwe; Höppner, Kathrin; Kühmstedt, Elke; Metzig, Robert; Plötz, Christian; Reinhold, Andreas; Schüler, Torben; Wojdziak, Reiner

2014-05-01

57

Oxygen and Hydrogen-Isotope Variations in a Firn Core, Eights Station Western Antarctica  

Microsoft Academic Search

Oxygen- and hydrogen-isotope analyses of samples from a firn core at Eights station indicate that annual accumulation over a 10-year interval was 39-40 g\\/cm -ø of water, confirming a condition of relatively heavy precipitation in the Bellingshausen Sea coastal area. The mean  value (--26.6) of the Oxs\\/O x6 ratios is consistent with the relatively low elevation (452 meters) and

Samuel Epstein; Robert P. Sharp

1967-01-01

58

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

PubMed Central

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 outfall. The findings revealed that the concentration of C. perfringens decreased with depth in the sediment and distance from the outfall. High percentages of tunicates and sea urchins were colonized with this bacterium along the transect. Coprostanol concentrations were also measured in sediment samples taken from each of the transect stations, and a similar trend was observed. These results are in agreement with the findings of previous studies performed with the water column and collectively provide evidence that the disposal of domestic wastes deserves special consideration in polar marine environments. PMID:9647835

Edwards, Diane D.; McFeters, Gordon A.; Venkatesan, M. Indira

1998-01-01

59

Propagation of low frequency geomagnetic field fluctuations in Antarctica: comparison between two polar cap stations  

NASA Astrophysics Data System (ADS)

We conduct a statistical analysis of the coherence and phase difference of low frequency geomagnetic fluctuations between two Antarctic stations, Mario Zucchelli Station (geographic coordinates: 74.7° S, 164.1° E; corrected geomagnetic coordinates: 80.0° S, 307.7° E) and Scott Base (geographic coordinates: 77.8° S 166.8° E; corrected geomagnetic coordinates: 80.0° S 326.5° E), both located in the polar cap. Due to the relative position of the stations, whose displacement is essentially along a geomagnetic parallel, the phase difference analysis allows to determine the direction of azimuthal propagation of geomagnetic fluctuations. The results show that coherent fluctuations are essentially detectable around local geomagnetic midnight and, in a minor extent, around noon; moreover, the phase difference reverses in the night time hours, indicating a propagation direction away from midnight, and also around local geomagnetic noon, indicating a propagation direction away from the subsolar point. The nigh time phase reversal is more clear for southward interplanetary magnetic field conditions, suggesting a relation with substorm activity. The introduction, in this analysis, of the Interplanetary Magnetic Field conditions, gave interesting results, indicating a relation with substorm activity during nighttime hours. We also conducted a study of three individual pulsation events in order to find a correspondence with the statistical behaviour. In particular, a peculiar event, characterized by quiet magnetospheric and northward interplanetary magnetic field conditions, shows a clear example of waves propagating away from the local geomagnetic noon; two more events, occurring during southward interplanetary magnetic field conditions, in one case even during a moderate storm, show waves propagating away from the local geomagnetic midnight.

Santarelli, L.; Lepidi, S.; Cafarella, L.

2007-11-01

60

Ground-based Observations for the Upper Atmosphere at King Sejong Station, Antarctica  

NASA Astrophysics Data System (ADS)

Since the operation of the King Sejong Station (KSS) started in Antarctic Peninsula in 1989, there have been continuous efforts to perform the observation for the upper atmosphere. The observations during the initial period of the station include Fabry-Perot Interferometer (FPI) and Michelson Interferometer for the mesosphere and thermosphere, which are no longer in operation. In 2002, in collaboration with York University, Canada, the Spectral Airglow Temperature Imager (SATI) was installed to observe the temperature in the mesosphere and lower thermosphere (MLT) region and it has still been producing the mesopause temperature data until present. The observation was extended by installing the meteor radar in 2007 to observe the neutral winds and temperature in the MLT region during the day and night in collaboration with Chungnam National University. We also installed the all sky camera in 2008 to observe the wave structures in the MLT region. All these observations are utilized to study on the physical characteristics of the MLT region and also on the wave phenomena such as the tide and gravity wave in the upper atmosphere over KSS that is well known for the strong gravity wave activity. In this article, brief introductions for the currently operating instruments at KSS will be presented with their applications for the study of the upper atmosphere

Jee, Geonhwa; Kim, Jeong-Han; Lee, Changsup; Kim, Yong Ha

2014-06-01

61

Case study of a mesospheric wall event over Ferraz station, Antarctica (62° S)  

NASA Astrophysics Data System (ADS)

On 16-17 July 2007 during an observational campaign at Comandante Ferraz Antarctic Station (62° S, 58° W), a mesospheric wall was observed with an airglow all-sky imager. The wave appeared like an extensive dark region in the all-sky airglow images, with a large depletion in the OH emission. Simultaneous mesospheric winds measured with a MF radar at Rothera station and temperature profiles from SABER instrument, on board of TIMED satellite, were used to obtain the propagation condition of the wave. Wind measurements during four days, around the time of observation of the wave, are presented in order to discuss the type and consistence of the duct in which this wave was propagating. By using wavelet analysis and tidal amplitude components we found that 12 and 8 h components were the most important periodicities around the time interval of the wave observation. A collocated imaging spectrometer, for mesospheric temperature measurements, has been operated simultaneously with the all-sky imager. Direct effects of the mesospheric front have been seen in the spectrometric measurements, showing an abrupt decrease in both OH intensity and rotational temperature when the wave front passes overhead. The main contribution of the present work is the investigation of the type of duct in which the wall event was propagating. We found evidences for a thermal duct structure to support the mesospheric wall propagation. This result was obtained by two types of analysis: (a) the tidal components analysis and winds filtering (harmonic analysis), and (b) comparison between the terms of the m2 dispersion relation.

Bageston, J. V.; Wrasse, C. M.; Hibbins, R. E.; Batista, P. P.; Gobbi, D.; Takahashi, H.; Andrioli, V. F.; Fechine, J.; Denardini, C. M.

2011-01-01

62

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

NASA Technical Reports Server (NTRS)

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.

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

1989-01-01

63

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

NASA Technical Reports Server (NTRS)

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.

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

1988-01-01

64

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

NASA Technical Reports Server (NTRS)

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.

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

1988-01-01

65

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

SciTech Connect

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.

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

1989-11-30

66

A sediment mesocosm experiment to determine if the remediation of a shoreline waste disposal site in Antarctica caused further environmental impacts.  

PubMed

A shoreline waste disposal site at Casey Station, Antarctica was removed because it was causing impacts in the adjacent marine environment (Brown Bay). We conducted a field experiment to determine whether the excavation created further impacts. Trays of clean, defaunated sediment were deployed at two locations within Brown Bay and two control locations, two years prior to remediation. Trays were sampled one year before, 1month before, 1month after and two years after the excavation. An increase in metals was found at Brown Bay two years after the remediation. However there was little evidence of impacts on sediment assemblages. Communities at each location were different, but differences from before to after the remediation were comparable, indicating there were unlikely to have been further impacts. We demonstrate that abandoned waste disposal sites in hydrologically active places in Antarctica can be removed without creating greater adverse impacts to ecosystems downstream. PMID:25306301

Stark, Jonathan S; Johnstone, Glenn J; Riddle, Martin J

2014-12-15

67

Assessment of metal contamination using X-ray fluorescence spectrometry and the toxicity characteristic leaching procedure (TCLP) during remediation of a waste disposal site in Antarctica.  

PubMed

The remediation of the Thala Valley landfill, Casey Station, East Antarctica, is part of efforts to clean-up contaminated sites associated with the Australian Antarctic Program. These sites, ranging from abandoned rubbish dumps to fuel spills, are contaminated principally with metals and petroleum hydrocarbons. Remediation success depends on accurate, cost-effective and timely--fit-for-purpose--chemical analysis of soil and water samples from the site, which is required to guide excavation, the in situ or off-site treatment and disposal of contaminated material, and to validate satisfactory remediation. Owing to the remote location of Antarctica, it is necessary to carry out chemical analyses on-site. Waste and soil contaminated with Pb, Zn, Cd, and Cu were excavated from Thala Valley for removal to Australia, treatment and disposal. Analysis of total metal concentrations in soil was performed at Casey Station with a transportable energy dispersive X-ray fluorescence (EDXRF) spectrometer. Soil samples were prepared using a simple size-fractionation method to expedite sample throughput. A method for assessing contaminant mobility in solid waste (toxicity characteristic leaching procedure, TCLP) was also used to characterise soil. Although this was more labour-intensive and time-consuming than the total metals analysis, it was of great utility because leachable metals were often significant determinants in the assessment of contaminated soil. The combined data helped managers during remediation, directing excavation and allowing waste to be classified for treatment and disposal before its return to Australia. PMID:18175018

Stark, Scott C; Snape, Ian; Graham, Nicholas J; Brennan, John C; Gore, Damian B

2008-01-01

68

Soil formation in coastal continental Antarctica (Wilkes Land)  

Microsoft Academic Search

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

Lothar Beyer; Kristina Pingpank; Gunther Wriedt; Manfred Bölter

2000-01-01

69

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

NASA Technical Reports Server (NTRS)

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.)

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

70

Simultaneous PMC and PMSE observations with a ground-based lidar and SuperDARN HF radar at Syowa Station, Antarctica  

NASA Astrophysics Data System (ADS)

A Rayleigh-Raman lidar system was installed in January 2011 at Syowa Station, Antarctica (69.0° S, 39.6° E). Polar mesospheric clouds (PMCs) were detected by lidar at around 22:30 UTC (LT -3 h) on 4 February 2011, which was the first day of observation. This was the first detection of PMCs over Syowa Station by lidar. On the same day, a Super Dual Auroral Radar Network (SuperDARN) HF radar with oblique-incidence beams detected polar mesospheric summer echoes (PMSE) between 21:30 and 23:00 UTC. This event is regarded as the last PMC activity around Syowa Station during the austral summer season (2010-2011), since no other PMC signals were detected by lidar in February 2011. This is consistent with results of PMC and mesopause temperature observations by satellite-born instruments of AIM (Aeronomy of Ice in the Mesosphere)/CIPS (Cloud Imaging and Particle Size) and AURA/MLS (Microwave Limb Sounder) and horizontal wind measurements taken by a separate MF radar. Doppler velocity of PMSE observed by the HF radar showed motion toward Syowa Station (westward). This westward motion is consistent with the wind velocities obtained by the MF radar. However, the PMSE region showed horizontal motion from a north-to-south direction during the PMC event. This event indicates that the apparent horizontal motion of the PMSE region can deviate from neutral wind directions and observed Doppler velocities.

Suzuki, H.; Nakamura, T.; Ejiri, M. K.; Ogawa, T.; Tsutsumi, M.; Abo, M.; Kawahara, T. D.; Tomikawa, Y.; Yukimatu, A. S.; Sato, N.

2013-10-01

71

Quantifying DNS Namespace Influence6 Casey Deccioa,  

E-print Network

Quantifying DNS Namespace Influence6 Casey Deccioa, , Jeff Sedayaob , Krishna Kantc , PrasantUniversity of California Davis, 1 Shields Ave., Davis, CA, USA Abstract Name resolution using the Domain Name System (DNS the control of the domain's owner. In this article we review the DNS protocol and several DNS server

California at Davis, University of

72

Welcome to Antarctica!  

NSDL National Science Digital Library

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

73

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

SciTech Connect

This paper presents results from a series of measurements of atmospheric OClO covering the period April to October 1991, made at McMurdo Station, Antarctica. These measurements were made to extend the knowledge of the general role of atmospheric chlorine dioxide in the general problem of ozone depletion. It is now recognized that atmospheric depletion of ozone occurs in regions other than near the poles, and is mediated by processes beyond polar stratospheric clouds and accompanying photochemistry. This paper reports on a seasonal study of chlorine dioxide abundances using visible and near-ultraviolet absorption spectroscopy. Scattered light is the light source used for many of the observations. The observed abundances are combined with other measurements of NO[sub 2] and NO[sub 3], and a simple box type circulation model to infer that these species can be transported to lower latitudes, and exposed to sunlight, resulting in atmospheric ozone depletion.

Sanders, R.W.; Solomon, S.; Mount, G.H. (National Oceanic and Atmospheric Administration, Boulder, CO (United States)); Smith, J.P.; Perliski, L.; Miller, H.L. (Univ. of Colorado, Boulder (United States)); Keys, J.G. (Department of Scientific and Industrial Research, Lauder, Central Otago (New Zealand)); Schmeltekopf, A.L. (A.L. Schmeltekopf, Marshall, NC (United States))

1993-04-20

74

Nitrate analysis of snow and ice core samples collected in the vicinity of a waste detonation event, McMurdo Station, Antarctica  

SciTech Connect

On December 30, 1991, a small quantity of hazardous materials was detonated at a site near McMurdo Station, Antarctica. The materials involved in the detonation represented highly reactive or explosive wastes that could not be transported safely for disposal in the United States. Detonation was therefore considered the safest and most effective means for disposing these hazardous materials. One concern regarding the detonation of these substances was that the process could generate or distribute measurable quantities of contaminants to the area surrounding the detonation site. Nitrate was selected as a tracer to document the distribution of contaminants from the detonation. Snow and ice cores were collected about 4 months after the event. These cores were analyzed for nitrate concentrations in May 1993, and a map was generated to show the extent of nitrate contamination. This report describes the collection of these samples and summarizes the analytical results.

White, G.J.; Lugar, R.M.; Crockett, A.B.

1994-07-01

75

First observations of ionospheric irregularities and flows over the south geomagnetic pole from the SuperDARN HF radar at McMurdo Station, Antarctica  

NASA Astrophysics Data System (ADS)

In February 2010 a new SuperDARN radar began operation at McMurdo Station, Antarctica. The radar’s orientation places the south geomagnetic pole near the center of the field of view at about 1200 km range. The radar is the highest latitude radar of the SuperDARN network, both geographically and geomagnetically, and the observations have a different character than those of the auroral zone radars. One particular feature of note is the high incidence of observed backscatter. When ionospheric altitudes are above the solar shadow height the incidence of observation is greater than 80% for a large portion of the radar field of view. This is indicative of the near constant presence of field-aligned density irregularities in the polar cap. This paper presents statistics of the observations along with estimates of the convection velocity maps. Prevailing IMF and solar wind velocity were taken from the Omni database and compared to the observed flows.

Bristow, W. A.; Parris, R. T.; Spaleta, J.

2010-12-01

76

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.

77

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

NASA Technical Reports Server (NTRS)

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.

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

2010-01-01

78

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

USGS Publications Warehouse

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

Lisle, J.T.; Smith, J.J.; Edwards, D.D.; McFeters, G.A.

2004-01-01

79

Analysis of the Use of Wind Energy to Supplement the Power Needs at McMurdo Station and Amundsen-Scott South Pole Station, Antarctica (Poster)  

SciTech Connect

This poster summarizes the analysis of the inclusion of wind-driven power generation technology into the existing diesel power plants at two U.S. Antarctic research stations, McMurdo and Amundsen-Scott South Pole Station. Staff at the U.S. Department of Energy's National Renewable Energy Laboratory (NREL) conducted the analysis. Available data were obtained on the wind resources, power plant conditions, load, and component cost. We then used NREL's Hybrid2 power system modeling software to analyze the potential and cost of using wind turbine generators at the two aforementioned facilities.

Baring-Gould, E. I.; Robichaud, R.; McLain, K.

2005-05-01

80

THE METALEXER LEXER SPECIFICATION LANGUAGE Andrew Michael Casey  

E-print Network

THE METALEXER LEXER SPECIFICATION LANGUAGE by Andrew Michael Casey School of Computer Science Mc FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE Copyright c 2009 Andrew Michael Casey #12 and require much less action code than the originals. i #12;ii #12;R´esum´e Les outils de compilation moderne

Verbrugge, Clark

81

Analysis of the Use of Wind Energy to Supplement the Power Needs at McMurdo Station and Amundsen-Scott South Pole Station, Antarctica  

SciTech Connect

This report summarizes an analysis of the inclusion of wind-driven power generation technology into the existing diesel power plants at two U.S. Antarctic research stations, McMurdo and Amundsen-Scott South Pole Station. Staff at the U.S. Department of Energy's National Renewable Energy Laboratory (NREL) conducted the analysis. Raytheon Polar Services, which currently holds the private sector support contract for the two research stations, was a major contributor to this report. To conduct the analysis, available data were obtained on the wind resources, power plant conditions, load, and component cost. Whenever possible, we validated the information. We then used NREL's Hybrid2 power system modeling software to analyze the potential and cost of using wind turbine generators at the two aforementioned facilities. Unfortunately, the power systems and energy allocations at McMurdo and South Pole Station are being redeveloped, so it is not possible to validate future fuel use. This report is an initial assessment of the potential use of wind energy and should be followed by further, more detailed analysis if this option is to be considered further.

Baring-Gould, I.; Robichaud, R.; McLain, K.

2005-05-01

82

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)

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.

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

1989-01-01

83

Accuracy assessment of land surface temperature retrievals from Landsat 7 ETM + in the Dry Valleys of Antarctica using iButton temperature loggers and weather station data.  

PubMed

The McMurdo Dry Valleys of Antarctica are the largest snow/ice-free regions on this vast continent, comprising 1% of the land mass. Due to harsh environmental conditions, the valleys are bereft of any vegetation. Land surface temperature is a key determinate of microclimate and a driver for sensible and latent heat fluxes of the surface. The Dry Valleys have been the focus of ecological studies as they arguably provide the simplest trophic structure suitable for modelling. In this paper, we employ a validation method for land surface temperatures obtained from Landsat 7 ETM + imagery and compared with in situ land surface temperature data collected from four transects totalling 45 iButtons. A single meteorological station was used to obtain a better understanding of daily and seasonal cycles in land surface temperatures. Results show a good agreement between the iButton and the Landsat 7 ETM + product for clear sky cases. We conclude that Landsat 7 ETM + derived land surface temperatures can be used at broad spatial scales for ecological and meteorological research. PMID:24366817

Brabyn, Lars; Zawar-Reza, Peyman; Stichbury, Glen; Cary, Craig; Storey, Bryan; Laughlin, Daniel C; Katurji, Marwan

2014-04-01

84

Classroom Antarctica  

NSDL National Science Digital Library

As part of the Australian Antarctic Division, Classroom Antarctica gives dozens of downloadable Adobe Acrobat files that allow students to discover this unique continent. Subjects include the history of the scientific research undertaken on Antarctica, surviving its climate, its biological ecosystem, the land's physical characteristics and affects on climate, and much more.

1969-12-31

85

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

SciTech Connect

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.

NONE

1995-05-01

86

Ground-based monitoring of nitric oxide (NO) in the mesosphere and the lower thermosphere from Syowa Station in Antarctica  

NASA Astrophysics Data System (ADS)

Ion-molecule chemistry triggered by energetic particle precipitation (EPP) due to large solar proton events or geomagnetic storms influences the atmospheric minor constituents such as HOx, NOx and ozone from the upper stratosphere to the lower thermosphere. To understand the effect of the EPP on the middle atmosphere in the polar region, we installed a new spectroscopic radiometer at Syowa Station (69.00S, 39.85E) in the 52nd Japanese Antarctic Research Expedition. We have carried out ground-based continuous observations of spectral line of nitric oxide (NO) at 250.796 GHz since January 2012. We obtained 197 and 172 daily averaged NO spectra in 2012 and 2013 (until 30 September; DOY 273), respectively. The NO spectra are characterized by narrow line width of about 0.5MHz at FWHM, suggesting that the NO emitting region is between 75 and 100 km based on the relationship between the pressure broadening line width and the altitude. We derived partial column density of NO from the spectral intensity. We found two temporal variation patterns of the NO column density, i.e., long-term and short-term variations. The long-term variation is a seasonal one with a maximum in the winter and a minimum in the summer. The column density of NO during the winter was about 4 times larger than that during the summer. This seasonal variation is considered to be related to the atmospheric transport and the photo-dissociation of NO by solar radiation. The other short-term variation is associated with EPP events such as solar proton events and geomagnetic storms. Typical duration of the short-term variation is 5-10 days. At Syowa Station, we have found that the short-term variations were caused mainly by the precipitation of electrons rather than protons based on the comparison with the precipitating fluxes of protons and electrons obtained by the POES and METOP-02 satellites. We studied more detailed behavior of NO within a day by using high time resolution (˜ 3-hour) data for one of the short-term NO enhancement events in April 2012, which is the most prominent NO short-term event observed at Syowa Station since January 2012. We revealed a diurnal tendency that NO column density increased about twice at UT 0 during 3 days around the peak of the NO enhancement. Based on the comparison between the NO column density and the electron fluxes obtained by the POES and METOP-02, we interpret that this diurnal tendency resulted from the dawn-dusk asymmetry of the precipitated electrons with energies 30-300 keV.

Mizuno, Akira; Nakamura, Takuji; Miyoshi, Yoshizumi; Fujiwara, Hitoshi; Tsutsumi, Masaki; Ejiri, Mitsumu K.; Nagahama, Tomoo; Isono, Yasuko; Kataoka, Ryuho; Hiroyuki, Maezawa; Uemura, Miku

87

Geoenvironments from the vicinity of Arctowski Station, Admiralty Bay, King George Island, Antarctica: vulnerability and valuation assessment  

USGS Publications Warehouse

The use of a geographic information system (GIS) allows the mapping and quantification of biotic and physical features of importance to the environmental planning of Antarctic areas. In this paper we examined the main aspects of the geoenvironments of Arctowski Station vicinity (Admiralty bay, Maritime Antartica), by means of a photointerpretation of an orthomosaic at 1:6000 scale, produced by non-conventional aerial photographs obtained by the Brazilian Cryosols project. We carried out a preliminary environmental valuation and vulnerability assessment of the area. Hence, geoenvironments were classified and ranked according with their biological valuation and vulnerability (fragility), mapping 20 units covering approximately 150 ha. The most fragile geoenvironmental units were former and present penguin rookeries with different vegetation covers, all very prone to degradation by over-trampling and human perturbations. The relationships between each geoenvironment were also explored, emphasizing the ecological aspects and their valuation. In quantitative terms, the most vulnerable and fragile units (classes 4 and 5) occupy nearly 22 % of the total area, being highly concentrated near the coastal areas. There, ornithogenic input is an important factor favoring the vegetation development.

Schaefer, Carlos Ernesto G.R.; Santana, Rogério Mercandelle; Simas, Felipe Nogueira Bello; Francelino, Márcio R.; Filho, Elpídio Inácio Fernandes; Albuquerque, Miriam Abreu; Calijuri, Maria Lúcia

2007-01-01

88

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

NASA Astrophysics Data System (ADS)

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

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

2011-11-01

89

Cool Antarctica  

NSDL National Science Digital Library

Paul Ward, the designer of this site, spent over two years in Antarctica as a marine biologist with the British Antarctic Survey. Currently a teacher at a community college in Britain, Ward decided to develop this site to provide information about Antarctica's history, wildlife, and the various explorers who have traveled across the continent. The section featuring Ward's photographs is quite compelling, featuring hundreds of pictures of wildlife, the area's mountains, and icebergs. The historical pages are quite detailed, particularly those about the legendary Ernest Shackleton and his amazing Trans-Antarctica Expedition of 1914 to 1917. Persons looking for material about visiting Antarctica will find a section dedicated to helping people prepare for a visit to the area, including information about various cruise operators and what type of clothing is most suitable.

90

Atmospheric rivers in Antarctica?  

NASA Astrophysics Data System (ADS)

Changes and variability in the surface mass balance signify one of the most puzzling questions of the present and future changes in Antarctica. In particular, understanding accumulation in the Eastern part of Antarctic continent presents a great challenge due to sparse and erratic observational network. Several previous publications reported an anomalously high precipitation in May 2009 in Dronning Maud Land, East Antarctica. This anomaly, supported by weather station data from the Princess Elisabeth station, 71°057' S, 23°021' E, 1392m asl, 173 km inland, also corresponded to anomalously high meridional moisture transport across the Southern Ocean inland. Using data from the ERA-Interim reanalysis project and a modified definition for the polar regions, May 2009 event has been classified as an atmospheric river event. Atmospheric river events, traditionally defined in the midlatitudes, are particularly strong and narrow corridors of moisture in middle atmosphere that can result in intense precipitation events once they reach the coast. May 2009 event was the first atmospheric river identified as far south as the Antarctic continent. In this study we perform a detailed analysis of the May 2009 atmospheric river event utilizing data from ERA -Interim and Weather Research and Forecasting (WRF) model simulations. We assess the role of the large-scale atmospheric circulation, particularly the role of the Zonal Wave 3 anomaly. We also investigate the synoptic-scale development of a storm that led to anomalous precipitation event in East Antarctica. We assess the role of upper and lower level forcing with the help of the quasi-geostrophic omega equation. We believe that such in-depth analysis of the dynamics of an atmospheric river event is crucial for better understanding present and future accumulation in the East Antarctica.

Tsukernik, M.; Lynch, A. H.

2013-12-01

91

SPRILIB Antarctica  

NSDL National Science Digital Library

The Scott Polar Research Institute at the University of Cambridge has recently made available online the database, SPRILIB Antarctica. SPRILIB Antarctica, a subset of SPRILIB, a polar and glaciological bibliographic database, contains 33,000 records from 1602 to 1996. The database offers comprehensive coverage of Antarctic literature on all subjects in all available languages for the period before 1962. However, it only includes some periodical articles and conference papers for the period after 1962. This database is intended to complement the Antarctic Bibliography at the Cold Regions Bibliography page of the Library of Congress site, and for the period after 1962, the Antarctic Bibliography contains comprehensive coverage of Antarctic literature. The SPRILIB Antarctica database is searchable by keyword, author, time period, place, expedition, or date of publication.

92

Classroom Antarctica  

NSDL National Science Digital Library

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

Haywood, Elizabeth

93

Antarctica Geology  

NSDL National Science Digital Library

This site contains information about the continent of Antarctica. There is a classroom practice and instructional module. The students will be able to describe the general geology of the land under the Antarctic ice and to explain from where the rocks may have come.

94

Undermining Antarctica  

SciTech Connect

Antarctica is not a global footnote. Its seas contain one of the world's richest concentrations of marine life. And the continent and adjacent shelf may harbor quantities of oil, gas, and other minerals. Many nations want to cash in on these resources. So in 1980 the member countries of the Antarctic Treaty - the agreement that sets the continent aside as a peaceful scientific reserve - signed a pact to regulate the harvesting of fish and other Antarctic life. Now the group, consisting today of 37 nations, is trying to finish a legal framework for exploiting minerals in the region. Antarctica plays a vital role in global atmospheric and oceanic systems. Its vast frozen crust, which accounts for more than 90 percent of the world's ice, greatly affects weather and sea levels and contains an invaluable record of the earth's climatic history. The continent provides precious information on increases in atmospheric carbon dioxide and global pollutants such as DDT. In other words, what happens to Antarctica is of vital importance to us all. It is essential, then, that the minerals pact now being devised heed the concerns of the many nations that don't have a say in Antarctica today, and that it does not endanger this precious continent.

Mitchell, B.

1988-02-01

95

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.

96

Astronomy in Antarctica  

NASA Astrophysics Data System (ADS)

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

Burton, Michael G.

2010-10-01

97

Tardigrades of the Australian Antarctic Territories: the Windmill Islands, East Antarctica  

Microsoft Academic Search

Six species of tardigrades,Pseudechiniscus suillus, Macrobiotussp.,Hypsibius antarcticus, Ramajendas frigidus, Diphascon chilenenseandDiphascon pinguewere extracted from mosses and lichens from the ice-free regions of the Windmill Islands near Casey Base, East Antarctica. Significant positive associations were found between the three common species (Pseudechiniscus suillus, Hypsibius antarcticus, Diphascon chilenense) and bryophytes, whereas strong negative associations were found between these species and algae and

W. R. MILLER; J. D. MILLER; H. HEATWOLE

1996-01-01

98

Discover Antarctica  

NSDL National Science Digital Library

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

99

Curriculum Vitae Casey J. Law Radio Astronomy Lab  

E-print Network

Curriculum Vitae ­ Casey J. Law Radio Astronomy Lab University of California Hearst Field Annex ­ B://astro.berkeley.edu/claw 1 Education Northwestern University, Ph.D., Astrophysics (2007) Boston University, M.A., Astronomy: Radio Astronomy Lab Postdoctoral Fellow at UC Berkeley. Worked with Geoff Bower, Don Backer, and Carl

Militzer, Burkhard

100

Genome diversity in microbial Casey L. McGrath1  

E-print Network

Genome diversity in microbial eukaryotes Casey L. McGrath1 and Laura A. Katz1,2 1 Department as more data from eukaryotic microbes become available. The diversity of microbial eukaryotes Interpreting Biology, UMass-Amherst, Amherst, MA 01003, USA The genomic peculiarities among microbial eukaryotes

Katz, Laura

101

A BARREL of fun in AntARcticA  

E-print Network

A BARREL of fun in AntARcticA National Aeronautics and Space Administration www.nasa.gov Volume 10 their own remote balloon field campaigns. This is the second time BARREL has taken to the skies over over Halley station to float above Antarctica and observe magnetic fields. Balloon Array for Radiation

Christian, Eric

102

Gateway to Antarctica  

NSDL National Science Digital Library

The International Centre for Antarctic Information and Research is produces the Gateway Antarctica. This Web server has been set up to provide the international community with information about Antarctica.

1969-12-31

103

The IRAIT Project Infrared Astronomy from Antarctica  

Microsoft Academic Search

The Concordia Station (Candidi 2003), on the Antarctica Plateau, will soon become one of the best observatories to perform infrared observations in the 2 20 mum atmospheric windows and beyond, thanks to its low sky background, low temperature and high atmospheric transparency. The possibility of passively cooling the telescope is a further advantage. We describe here the first permanent Antarctic

M. Busso; G. Tosti; F. Roncella; M. Bagaglia; G. Nucciarelli; R. Fastellini; O. Straniero; M. Dolci; M. Ragni; I. di Varano; L. Corcione; C. Abia; I. Dominguez; F. Rossi; A. Nicolini

2005-01-01

104

Discovery and exploration of Antarctica  

SciTech Connect

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.

Craddock, C.

1987-05-01

105

Estimation of mesospheric vertical winds from a VHF meteor radar at King Sejong Station, Antarctica (62.2S, 58.8W)  

NASA Astrophysics Data System (ADS)

For the first time, vertical winds near the mesopause region were estimated from radial velocities of meteor echoes detected by a VHF meteor radar at King Sejong Station (KSS) in 2011 and 2012. Since the radar usually detects more than a hundred echoes every hour in an altitude bin of 88 - 92 km, much larger than other radars, we were able to fit measured radial velocities of these echoes with a 6 component model that consists of horizontal winds, spatial gradients of horizontal winds and vertical wind. The conventional method of deriving horizontal winds from meteor echoes utilizes a 2 component model, assuming that vertical winds and spatial gradients of horizontal winds are negligible. We analyzed the radar data obtained for 8400 hours in 2012 and 8100 hours in 2011. We found that daily mean values of vertical winds are mostly within +/- 1 m/s, whereas those of zonal winds are a few tens m/s mostly eastward. The daily mean vertical winds sometimes stay positive or negative for more than 20 days, implying that the atmosphere near the mesopause experiences episodically a large scale low and high pressure environments, respectively, like the tropospheric weather system. By conducting Lomb-normalized periodogram analysis, we also found that the vertical winds have diurnal, semidiurnal and terdiurnal tidal components with about equal significance, in contrast to horizontal winds that show a dominant semidiurnal one. We will discuss about uncertainties of the estimated vertical wind and possible reasons of its tidal and daily variations.

Kim, Y.; Lee, C.; Kim, J.; Jee, G.

2013-12-01

106

Antarctica Part Two  

NSDL National Science Digital Library

In this video, Jonathan treks all the way to Antarctica to investigate life south of the polar circle. Along the way he dives in the majestic kelp forests of Patagonia, where crabs rule the sea floor. Once he arrives in Antarctica, his adventures continue. He swims with penguins, dives under an iceberg, meets a massive jellyfish 3 feet 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.

Productions, Jonathan B.

2011-06-06

107

Bringing Antarctica Home  

ERIC Educational Resources Information Center

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

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

2012-01-01

108

Some Background on Antarctica  

NSDL National Science Digital Library

This online article provides an overview of Antarctica and the reasons so many scientists are drawn to the continent. It includes a compilation of facts, an overview of the kinds of questions that can be answered in Antarctica, and insight into the scientific importance of the research conducted there.

109

Antarctica: little paying perspectives  

SciTech Connect

The continent of Antarctica has a surface of 14,200,000 sq km. It rests upon one of the deeper epicontinental platforms of the world, which descends steeply to the oceanic depths. The 200-m isobath is almost in its totality inside of the main ice zone. More than 95% of the continent itself is found under a layer of terrestrial ice composed of ca. 3,000,000 cu km of ice, with an average thickness of 2000 m. The ice and sea impede the access to the continent, and cyclonic storms surround the Antarctica in an endless sequence that moves from west to east. Almost all Antarctica geology is under ice, and only the highest places of mountains outcrop. The geologic structure is composed of 6 tectonic units. Antarctica has mineral resources, but the obstacles encountered in personnel and material movement make the Antarctica petroleum perspective very poor, since the recovery cost goes beyond the present selling price.

Ivanhoe, L.F.

1981-07-01

110

Antarctica Part One  

NSDL National Science Digital Library

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

Productions, Jonathan B.

2011-05-04

111

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

Microsoft Academic Search

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

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

2001-01-01

112

Antarctica - Lessons for a Mars exploration program  

NASA Technical Reports Server (NTRS)

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.

Mckay, C. P.

1985-01-01

113

Recent changes in solar irradiance in Antarctica  

SciTech Connect

A significant decrease in the annual sums of global irradiance reaching the surface in Antarctica, averaging -0.28 W m{sup -2} yr{sup -1}, was derived from an analysis of all complete years of measurement available from 12 pyranometer stations, 10 of which were on the coast. The decrease was greater than could be attributed to the nonhomogeneous nature of the database, the estimated errors of measurement, or changes in the amount of cloud cover. The smaller database of radiation balance measurements available showed no statistically significant change. Possible causes of these results are discussed, as is the implication that the recent surface warming in Antarctica is not due to radiative forcing. 49 refs., 3 figs., 5 tabs.

Stanhill, G.; Cohen, S. [Institute of Soils and Water, Bet Dagan (Israel)] [Institute of Soils and Water, Bet Dagan (Israel)

1997-08-01

114

North Station North Station  

E-print Network

North Station North Station North Station East Station ... ... North Station Water Tower Elysian, and so on. She then hides the renamed map and the permutation table in a safe. Next, Virgil tosses a coin

Chazelle, Bernard

115

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

ERIC Educational Resources Information Center

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

Belanger, Dian Olson

2004-01-01

116

Living and Working in Antarctica.  

ERIC Educational Resources Information Center

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

Kemp, Noel

117

Geographic names of Antarctica  

USGS Publications Warehouse

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.

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

1956-01-01

118

A Road to Results: Results-Based Accountability in the Annie E. Casey Foundation's Education Program  

ERIC Educational Resources Information Center

This report details the Annie E. Casey Foundation's four-year effort to develop a "results-based accountability" (RBA) approach to its K-12 education portfolio. Though still a work in progress, the Foundation's experience with RBA can help other philanthropic organizations and individual donors develop their own approaches to producing and…

Manno, Bruno V.

2006-01-01

119

Getting Results: Outcomes Management and the Annie E. Casey Foundations Jobs Initiative.  

ERIC Educational Resources Information Center

The Anne E. Casey Foundation (AECF) funded replications of effective jobs projects to achieve better job placement and retention for low-income, young adults. The six projects funded, collectively called the Jobs Initiative (JI), in Denver, Milwaukee, New Orleans, Philadelphia, Seattle, and St. Louis, used an outcomes framework developed by The…

Giloth, Robert; Phillips, William

120

2006 Michigan State University Board of Trustees 1 Karen McKnight Casey  

E-print Network

© 2006 Michigan State University Board of Trustees 1 Karen McKnight Casey Director Center for Service-Learning and Civic Engagement Michigan State University UOE Presentation to Utah Valley State College Administration September 13, 2007 The Mission of Service-Learning and Civic Engagement at Michigan

121

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 the time resolution of the cesium-iodide scintillator crystals with custom built analog-to-digital-converter boards (ADCs) for the KOTO experiment. Simulation shows that the time reso- lution should be better than

122

Comparative Performance Analysis of RDMA-Enhanced Ethernet Casey B. Reardon  

E-print Network

1 Comparative Performance Analysis of RDMA-Enhanced Ethernet Casey B. Reardon 1 , Alan D. George 1 Library [2]. With these tools in place, a new cost-effective networking solution is emerging, where provides an experimental performance analysis and comparison between three competing interconnect options

George, Alan D.

123

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

124

Retaining Low-Income Residents in the Workforce: Lessons from the Annie E. Casey Jobs Initiative.  

ERIC Educational Resources Information Center

Annie E. Casey Jobs Initiative sites recognize the challenge that long-term retention poses in today's labor market for low-income residents. They have developed key elements of an operational definition of retention, including the following: no limitation to one job, but only very limited gaps between jobs; and jobs in construction or other…

Giloth, Bob; Gewirtz, Susan

125

Extending Ladders: Findings from the Annie E. Casey Foundation's Jobs Initiative.  

ERIC Educational Resources Information Center

In 1995, the Anne E. Casey Foundation launched the Jobs Initiative (JI) in six cities to change labor market prospects for low-income young people in order to help them get jobs that could move their families out of poverty. The JI attempts to change the way employers recruit and supervise workers and how work is structured; to prepare workers and…

Fleischer, Wendy

126

POP Goes Antarctica?  

NSDL National Science Digital Library

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

Cowles, Susan

2002-01-01

127

Antarctica: Discovery & Exploration.  

ERIC Educational Resources Information Center

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

Gascoigne, Toss; Collett, Peter

128

Getting Antarctica down Cold!  

ERIC Educational Resources Information Center

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

Sandmeier, Kay; Greeson, Linda

1990-01-01

129

Married to Antarctica.  

ERIC Educational Resources Information Center

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

Monastersky, Richard

1991-01-01

130

Why Is It Always Cold in Antarctica?  

NSDL National Science Digital Library

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

131

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

NASA Astrophysics Data System (ADS)

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

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

2010-12-01

132

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

E-print Network

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

Ishida, Yuko

133

British Antarctic Survey: About Antarctica  

NSDL National Science Digital Library

This brief overview of Antarctica covers its wildlife (penguins and other birds, seals, whales, fish, plants) and its geography (ice features, geologic features, weather, the ozone hole). There is also a series of short articles on protecting Antarctica's environment, including waste disposal and cleanup, protecting wildlife and plants, and protecting special areas and historic sites. The teacher resources page features a link to 'Discovering Antarctica', a resource that is intended to enthuse young people in Antarctic research and to give teachers access to an authoritative resource from the UK's national Antarctic operator. Other topics include tourism in Antarctica and geopolitical issues (the Antarctic Treaty, place names, the British Antarctic Territory).

134

Ozone Hole Over Antarctica  

NASA Technical Reports Server (NTRS)

These images from the Total Ozone Mapping Spectrometer (TOMS) show the progressive depletion of ozone over Antarctica from 1979 to 1999. This 'ozone hole' has extended to cover an area as large as 10.5 million square miles in September 1998. The previous record of 10.0 million square miles was set in 1996. The Antarctic ozone hole develops each year between late August and early October. Regions with higher levels of ozone are shown in red. NASA and NOAA instruments have been measuring Antarctic ozone levels since the early 1970s. Large regions of depleted ozone began to develop over Antarctica in the early 1980s. Ozone holes of substantial size and depth are likely to continue to form during the next few years, scientists hope to see a reduction in ozone loss as levels of ozone-destroying CFCs (chlorofluorocarbons) are gradually reduced. Credit: Images by Greg Shirah, NASA Goddard Space Flight Center Scientific Visualization Studio

2002-01-01

135

Antarctica in Images  

NSDL National Science Digital Library

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

136

Learning About Antarctica's Past  

NSDL National Science Digital Library

Learning about Antarctica's past can give K-Grade 5 teachers and students lessons in geology, climate, and ecology along with literacy experiences in sequencing and time lines. The author identifies online resources for both adults and younger learners. A three-section unit plan begins with sequencing events and follows with earth's history over billions of years and the records found in rocks and fossils. The article appears in the free, online magazine Beyond Penguins and Polar Bears.

Landis, Carol

2011-01-01

137

Hydrology of Antarctica  

SciTech Connect

The hydrology of the Southern Ocean floor, the ice sheet covering Antarctica, and the bedrock underlying it is a matter of great interest. This article attempts to shed some light on the problem of the hydrology of this part of the world in the form of prognoses, because the available direct information on the subsurface waters of this vast region is completely inadequate. From the standpoint of their practical utilization, the fresh waters at the base of the Antarctic ice sheet and the waters below the permafrost of the larger islands of Antarctica are the most promising. The large artesian basins of Antarctica with a thick mantle of sedimentary rocks are of interest for their oil and gas potential. One can be certain also of obtaining thermal waters from some of the artesian structures of this continent. Special attention should be paid to the fumaroles and solfataras in areas of present-day volcanism, and to the rift zones, where thermal waters may also be obtained. 16 references.

Kiryukhin, V.A.; Tolstikhin, N.I.

1988-01-01

138

Climatology of GPS scintillations over Antarctica under solar minimum conditions  

NASA Astrophysics Data System (ADS)

We analyse GNSS ionospheric scintillation data recorded in Antarctica to investigate the conditions of the near-Earth environment leading to scintillation scenarios, producing a "scintillation climatology" over a large geomagnetic quiet period. Within this scope we realize maps of scintillation occurrence as a function of the magnetic local time (MLT) and of the altitude adjusted corrected geomagnetic coordinates (AACGM). The maps are realized merging observations of two GISTMs (GPS Ionospheric Scintillation and TEC Monitor) located at Mario Zucchelli Station (74.7°S, 164.1°E) and Concordia Station (75.1°S, 123.2°E) in Antarctica during 2008. The results highlight the possibility to investigate the impact of ionospheric irregularities on the phase and amplitude of GNSS signals, evidencing the cusp/cap and auroral contributions. This works aims to contribute to the development of nowcasting and forecasting tools for GNSS ionospheric scintillation.

Spogli, Luca; Alfonsi, Lucilla; Romano, Vincenzo; de Franceschi, Giorgiana; Mitchell, Cathryn N.

2010-05-01

139

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

Microsoft Academic Search

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

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

2009-01-01

140

Surface wave tomography of South America and Antarctica  

NASA Astrophysics Data System (ADS)

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

Vdovin, Oleg Yurevich

141

The crustal thickness of West Antarctica  

NASA Astrophysics Data System (ADS)

P-to-S receiver functions (PRFs) from the Polar Earth Observing Network (POLENET) GPS and seismic leg of POLENET spanning West Antarctica and the Transantarctic Mountains deployment of seismographic stations provide new estimates of crustal thickness across West Antarctica, including the West Antarctic Rift System (WARS), Marie Byrd Land (MBL) dome, and the Transantarctic Mountains (TAM) margin. We show that complications arising from ice sheet multiples can be effectively managed and further information concerning low-velocity subglacial sediment thickness may be determined, via top-down utilization of synthetic receiver function models. We combine shallow structure constraints with the response of deeper layers using a regularized Markov chain Monte Carlo methodology to constrain bulk crustal properties. Crustal thickness estimates range from 17.0±4 km at Fishtail Point in the western WARS to 45±5 km at Lonewolf Nunataks in the TAM. Symmetric regions of crustal thinning observed in a transect deployment across the West Antarctic Ice Sheet correlate with deep subice basins, consistent with pure shear crustal necking under past localized extension. Subglacial sediment deposit thicknesses generally correlate with trough/dome expectations, with the thickest inferred subice low-velocity sediment estimated as ˜0.4 km within the Bentley Subglacial Trench. Inverted PRFs from this study and other published crustal estimates are combined with ambient noise surface wave constraints to generate a crustal thickness map for West Antarctica south of 75°S. Observations are consistent with isostatic crustal compensation across the central WARS but indicate significant mantle compensation across the TAM, Ellsworth Block, MBL dome, and eastern and western sectors of thinnest WARS crust, consistent with low density and likely dynamic, low-viscosity high-temperature mantle.

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

2014-01-01

142

Direct gravimetric determination of aerosol mass concentration in central antarctica.  

PubMed

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

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

2011-01-01

143

Clostridia in soil of the Antarctica.  

PubMed

From the soil in the area around the Syowa Station, the East Ongul Island, the Antarctica, a total of 193 strains of clostridia were isolated and identified. It was surprising that the soil samples taken from the places which were considered to be scarcely contaminated by human beings and animals contained many clostridia. One hundred and fifty-five strains were assigned to 11 species, including C. perfringens, C. bifermentans, C. sordellii, C. sporogenes, C. plagarum, C. paraperfringens, C. septicum, C. tertium, C. cadaveris, C. butyricum and C. felsineum, but 38 strains remained unidentified. C. perfringens, C. bifermentans and C. sordellii were isolated very frequently and C. sporogenes less frequently. All the strains of C. sordellii were nonpathogenic and had almost the same characteristics as those of C. bifermentans except for the attitude in the urease test. The peculiar distribution and characteristics of the clostridia in the Antarctic soil were discussed in comparison with those found in the soil in Japan. PMID:175201

Miwa, T

1975-08-01

144

Petroleum geology of western Antarctica  

SciTech Connect

Antarctica's geology is mostly obscured by thick, moving ice that covers 95% of the land and continental shelf. Reconnaissance investigations of outcrops, shallow boreholes, and geophysical surveys are limited and peripheral owing to ice coverage. However, it is possible to outline substantial elements of the regional geology. Further insight is gained by comparison to analogous sedimentary provinces, especially provinces once adjoined within the framework of the Gondwana supercontinent until middle Cretaceous. The petroleum potential of Antarctica, as in the case of the other related high-standing Gondwana continental fragments, is in Early Cretaceous rifts associated with the Gondwana breakup and with the Pacific convergence in the west Antarctica back arc. The Pacific-facing western Antarctica includes two structural provinces: (1) the Cretaceous and younger interior rift system on the east side of the Weddell and Ross Sea embayment, which contain aulacogens that form the boundary with East Antarctica and (2) the back-arc and fore-arc basins adjoining the Antarctica Peninsula and extending into Marie Byrd Land and the Bellingshausen Sea which are associated with the eastward convergence of the Pacific plate. The petroleum potential of the rifts may be assessed by analogies with related rifts of Australia, India, and South Africa; assessment of the convergent basins of western Antarctica depends upon analogy with similar basins of South America, New Zealand, and Indonesia. An estimate of the petroleum potential of western Antarctica generally is comparable with oil and gas occurrences (both in overall quantity and in field sizes) in the other Gondwana continental fragments. However, in view of the thict moving ice cover, the remote locale, and severe climate, petroleum production is largely beyond technology at this time and probably is economically unfeasible.

Kingston, J. (Geological Survey, Santa Barbara, CA (USA))

1990-05-01

145

The United States in Antarctica -- Report of the U.S. Antarctic Program External Panel  

NSF Publications Database

... 3.0 Antarctica -- The Environment 3.0 Antarctica -- The Environment (continued) 4.0 Antarctica -- ... Antarctica -- Past and Present (continued) 5.0 Antarctica -- Significance Today 5.0 Antarctica -- ...

146

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

Microsoft Academic Search

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

E. Imre Friedmann; Christopher P. McKay; James A. Nienow

1987-01-01

147

Assessment of the wind power potential at SANAE IV base, Antarctica: a technical and economic feasibility study  

Microsoft Academic Search

This paper presents a study for the utilization of wind energy at the South African research station, SANAE IV, in Antarctica (71°40’ S 2° 50’ W). A procedure to evaluate the feasibility of utilising wind power for Antarctic stations is given. The analysis is based on the technical and economic aspects of installing and operating a wind turbine at remote

H. W. Teetz; T. M. Harms; T. W. von Backström

2003-01-01

148

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

NASA Astrophysics Data System (ADS)

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.

Yamamoto, Tatsuyuki; Imura, Satoshi; Yamamoto, Naoyuki

2010-08-01

149

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.

150

Investigating West Antarctica, Then and Now  

NSDL National Science Digital Library

This article profiles Charles Bentley, a geophysicist who has worked in Antarctica over a period of seven decades. The article provides an overview of his research as well as changes in the way scientists live and work in Antarctica.

Landis, Carol

151

Research on the Web: Snapshots of Antarctica  

NSDL National Science Digital Library

This Web research activity gives students a broad overview of Antarctica. They are asked to work as scientists, making predictions and observations and recording their findings. All directions are included in a printable handout. Students begin by gathering background information on Antarctica and polar research. They then view images of Antarctica taken from space and ones that compare its size to the United States. They end by answering questions about Antarctica's size, physical conditions, and why scientists conduct research there.

152

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

Microsoft Academic Search

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

P. Convey; D. Barnes; A. Morton

2002-01-01

153

Occurrence of nematodes, tardigrades and rotifers on ice-free areas in East Antarctica  

Microsoft Academic Search

Nematodes, rotifers and tardigrades were collected on three nunataks (mountain peaks penetrating the ice sheet) in Vestfjella, on six nunataks in Heimefrontfjella and on the Schirmacher Oasis in East Antarctica in the austral summers of 1996\\/97 and 2001\\/02. Most samples were taken on the nunatak Basen in Vestfjella where the Swedish station Wasa is located. The microfauna was patchily distributed

Björn Sohlenius; Sven Boström; K. Ingemar Jönsson

2004-01-01

154

Radiofrequency Ice Properties Measurements at Taylor Dome, Antarctica, in sup- port of the ANITA experiment  

Microsoft Academic Search

Radiowave detection of the Cherenkov radiation produced by neutrino-ice collisions requires an understanding of the radiofrequency (RF) response of cold polar ice. We herein report on a series of ra- dioglaciological measurements performed approximately 10 km north of Taylor Dome Station, Antarctica from Dec. 6, 2006 ñ Dec. 16, 2006. Using RF signals broadcast from a dual-polarization horn antenna on

D. Z. BESSON; J. NAM; S. MATSUNO; S. W. BARWICK; J. J. BEATTY; W. R. BINNS; C. CHEN; P. CHEN; J. M. CLEM; A. CONNOLLY; P. F. DOWKONTT; M. A. DUVERNOIS; R. C. FIELD; D. GOLDSTEIN; A. GOODHUE P. W. GORHAM; C. HAST; C. L. HEBERT; S. HOOVER; M. H. ISRAEL; J. KOWALSKI; J. G. LEARNED; K. M. LIEWER; E. LUSCZEK LINK; B. MERCURIO; C. MIKI; P. MIO; C. J. NAUDET; J. NG; R. NICHOL; K. PALLADINO; K. REIL; A. ROMERO-WOLF; M. ROSEN; L. RUCKMAN; D. SALTZBERG; D. SECKEL; G. S. VARNER; D. WALZ; F. WU

155

Solar Eclipses Observed from Antarctica  

NASA Astrophysics Data System (ADS)

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.

Pasachoff, Jay M.

2013-01-01

156

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...

157

High-field magnetic force microscopy as susceptibility imaging Casey Israel, Weida Wu, and Alex de Lozannea  

E-print Network

High-field magnetic force microscopy as susceptibility imaging Casey Israel, Weida Wu, and Alex de an extension of variable-temperature magnetic force microscopy MFM that allows spatial discrimination between.1063/1.2221916 Magnetic force microscopy MFM was developed as a scanning probe technique for mapping out magnetic field

Wu, Weida

158

Good Wheel Hunting: UMass Lowell's Scavenger Hunt Robot System Robert Casey, Andrew Chanler, Munjal Desai, Brenden Keyes,  

E-print Network

Good Wheel Hunting: UMass Lowell's Scavenger Hunt Robot System Robert Casey, Andrew Chanler, Munjal into the Scavenger Hunt Competition at the AAAI-2005 Robot Competition and Exhibition. The scavenger hunt entry, all used to locate the objects in the scavenger hunt. INTRODUCTION The AAAI-2005 Scavenger Hunt

Yanco, Holly A.

159

Forest transitions and ecosystem services in Zimbabwe Supervisors: Dr Casey Ryan (UoE), Dr Isla Grundy (University of Zimbabwe)  

E-print Network

Forest transitions and ecosystem services in Zimbabwe Supervisors: Dr Casey Ryan (UoE), Dr Isla and a variety of other ecosystem services. However the expansion of agricultural land and the curing of tobacco is accelerating deforestation and forest degradation rates. These structural changes to the ecosystem threaten

160

Bouvet Island near Antarctica  

Atmospheric Science Data Center

... became a Nature Reserve in 1971. An automated weather station was established in 1977. A nuclear bomb was detonated between ... D.C. The Terra spacecraft is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. The MISR data were obtained from the NASA ...

2013-04-16

161

An Automatic Video Meteor Observation Using UFO Capture at the Showa Station  

NASA Astrophysics Data System (ADS)

The goal of our study is to clarify meteor activities in the southern hemi-sphere by continuous optical observations with video cameras with automatic meteor detection and recording at Syowa station, Antarctica.

Fujiwara, Y.; Nakamura, T.; Ejiri, M.; Suzuki, H.

2012-05-01

162

Antarctica as a Martian model.  

NASA Technical Reports Server (NTRS)

Results of a survey of a variety of environments in the dry valleys of Antarctica, ranging from mountain crests to valley floors. The main purpose of the investigation was the determination of active microbial multiplication in the soil. A series of techniques was employed which permitted the detection of bacterial growth in situ. All evidence points to an active growth of micro-organisms in the Antarctic soil in all locations examined. The measurements were supported by electron micrographs of soil films which showed colonial growth covering soil particles. These findings suggest that Antarctica does not serve as a useful model for the Martian environment in evaluating quarantine standards.

Vishniac, W. V.; Mainzer, S. E.

1973-01-01

163

Tectonic development of West Antarctica and its relation to East Antarctica  

SciTech Connect

Over several years, the author has compiled data and conducted field research to gain an understanding of the relationship between East and West Antarctica through geologic time. The investigations have focused on the Scotia Arc and the region at the base of the Antarctic Peninsula extending to the Ellsworth, Thiel, and Whitmore mountains. During the 1983-1984 austral summer, US and British geologists began an intensive investigation in the Ellsworth Mountains and Martin Hills, at Mount Smart, and near Siple Station. Field work includes geology, paleomagnetism, geochronology, and geophysics, with radio-echo sounding and aeromagnetic surveys conducted by British geophysicists. This investigation attempts to define the limits of the crustal blocks and determine the tectonic nature of the ice-covered area between them.

Dalziel, I.W.D. (Univ. of Texas, Austin (USA))

1987-09-01

164

Telemedical experiences at an Antarctic station.  

PubMed

Wintering-over in Antarctica represents a physician's most remote and inaccessible scenario, apart from a space station. Because of the harsh and unpredictable winter weather, Antarctic stations are typically inaccessible for over six months of the year. Telephone and fax communication, and recently other forms of telemedicine, have provided vital links to specialists. The author was the sole physician for more than 250 people wintering-over during the 1995 austral winter at McMurdo Station. There were several instances of serious or life-threatening illness where the author relied on teleconsultation. These cases included new-onset coronary artery disease, posterior hip dislocation, complicated Colles' fracture and acute appendicitis. There were also numerous consultations for non-emergency clinical presentations normally managed by specialists. Telemedicine was a crucial link to specialists from the remote and inaccessible environment of Antarctica. PMID:10534856

Hyer, R N

1999-01-01

165

What Organisms Live in Antarctica?  

NSDL National Science Digital Library

In these activities students will discover the characteristics that enable Antarctica's many life forms to live in this continent of extreme cold, wind, and extended periods of light and darkness. In this weeklong unit, students research how flora and fauna have adapted to thrive in Antarctica, and use their knowledge to create imaginary polar organisms. Throughout this module, students collect their findings in a portfolio. The comprehensive curriculum materials contain a Web activity in which students investigate the living conditions in Antarctica and some of the adaptations its organisms have made, a classroom activity in which students apply what they have learned to create models of imaginary polar creatures, several readings that provide a broad perspective, including excerpts from early explorers' journals, and question and answer interviews with scientists working in Antarctica. Teacher tools include individually downloadable readings, detailed daily breakdowns of tasks, teacher strategies for using the activities, a portfolio grading sheet, a project rubric sheet, a student handout with guidance for putting together their portfolios and examples of creative final projects, and additional readings.

166

Antarctica: A Cold Desert Ecosystem  

NSDL National Science Digital Library

This Antarctica lesson has students locate the continent on a globe and on a map, describe and illustrate major Antarctic ecosystems, and explain relationships between those ecosystems. They will also construct a rough map of Antarctic ecosystems and explore relationships among the creatures that populate them. This lesson can be adapted to focus on other regions, including the one in which students live.

167

Antarctica: geology and hydrocarbon potential  

SciTech Connect

The first impression of the hydrocarbon potential of Antarctica is generally negative. The environment is hostile and only 2% of the continent is seen through the ice. Careful study of the surprisingly ample volume of published data available on the geology and geophysics and Antarctica, coupled with the application of the principles and mechanics of plate tectonics relative to the oceans and adjacent land masses, gives a different and very positive attitude toward the hydrocarbon potential of this vast unexplored frontier area. On the basis of limited data, 21 sedimentary basins are identified for Antarctica and immediately adjacent areas. These include six onshore subglacial basins and 15 offshore basins. Excluding 11 basins considered to have little or no potential, the other 10 basins contain an estimated 16.9 million km/sup 3/ (4.05 million mi/sup 3/) of sediment having a potential hydrocarbon yield of 203 billion bbl oil equivalent. The problems associated with hydrocarbon exploration in Antarctica are formidable. Technology is adequate for seismic surveys and exploratory drilling of the Antarctic continental shelf, as concluded from current operations in the Arctic and from operating requirements of drilling rigs under construction. However, a working relationship among involved nations must first be evolved and production, storage, and transportation problems solved.

St. John, B.

1984-09-01

168

Research on the Web: Living and Working in Antarctica  

NSDL National Science Digital Library

This Web research activity has students examine travel information prepared by the Antarctic Support Services. All directions are included in a printable handout. Students begin by reviewing the U.S. Antarctic Program Participant Guide, which contains information to help researchers and staff prepare for life in this extreme environment. They then view images of the living and working spaces at the Palmer Station. They end by answering a series of questions, which helps them draw conclusions about the technologies humans have adopted in order to live and work in Antarctica.

169

Remote sensing and skywave digital communication from antarctica.  

PubMed

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

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

2009-01-01

170

Research on the Web: Antarctic Weather Stations  

NSDL National Science Digital Library

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

171

Assessment and Review of GIA Models for Antarctica and Greenland  

NASA Astrophysics Data System (ADS)

One of the major obstacles to reducing the uncertainty of GRACE-based ice mass balance estimates for the ice sheets during 2002-2011 is our poor control on the ongoing glacial isostatic adjustment of bedrock (GIA). The later adjustments cause vertical motions of rock at the crustal surface and at great depths within the mantle. These are sources of positive mass trend when measured in space gravimtery data. The poorly understood signal in Antarctica may be large enough to manifest uncertainties that approach 190 Gt/yr (Velicogna and Wahr, 2006), dominating the background error in trend for Antarctica, and potentially corrupting solutions for mass balance for ice drainage basins in the north and central parts of Greenland. This source of error is independent of method, and corrupts the interpretable trend in both spherical harmonic field or mascon releases. Two of the most recent GRACE mass balance assessments for GIA in Antarctica employ combinations of ICE5G and IJ05 models, both of which are now more than half a decade old. In part, because of the urgency to report to the IPCC on the mass balance of Antarctica with greater certainty, GIA modeling has been the focus of intense research in the past 6-7 years. Significant progress lies in three areas of research: i.) Constraint on paleo-ice sheet reconstruction coming from dated sedimentary coring ('bathtub rings') and moraine and nunatuk rock nuclide exposures ('dip sticks of the past'). This data is now rich enough that, in fact, for some areas of Antarctica we now know much more about ice mass evolution since Last Glacial Maximum (21 thousand years ago), that we do for the great Laurentide ice sheet of North America; ii.) Integration of simple ice dynamics models that are specifically constrained by these data (Whitehouse et al., 2011, ISAES XI Edinburgh); iii.) A more robust GPS data set for vertical motion trends of longer legacy (almost two decades in some cases) approaching 50 individual station records on bedrock (Thomas et al., 2011, ISAES XI Edinburgh). One upshot of these more recent Antarctic studies is that they reveal relatively older exposure and sediment dates. A great deal of ice (roughly half) had been lost to the ocean by 11.5 ka, (relatively more than in the IJ05 and ICE5G models). Furthermore, more precise lower elevation limits for ice fee nunataks and mountain outcrops throughout Last Glacial Maximum (e.g., Bentley et al., 2011) are retrieved. These reveal that the ice sheet was likely to be considerably less thick than in the ice domes of ICE5G in west Antarctica, and less thick in the western Weddell Sea, southernmost Antarctic Peninsula and coastal east Antarctica than in the IJ05 model. These two new features must be integrated into new predictions of the GRACE GIA correction for ice mass balance. The most immediate implications are that the past corrections for Antarctica are simply too large and that GRACE-based inference of mass loss are too large by substantial amounts. ICE5G corrections are likely too large by more than 50-60% and IJ05 too large by 20%, or more. New models for both Greenland and Antarctica are discussed.

Ivins, E. R.

2011-12-01

172

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.

173

Relationship between total ozone amounts and stratospheric temperature at Syowa, Antarctica  

SciTech Connect

Using statistical methods, the relationship has been studied between total ozone and 100-mbar temperatures at Syowa Station, Antarctica (69[degrees]S, 40[degrees]E), based on data obtained in 1961-1981 and 1982-1988, the time of ozone depletion in Antarctica. Results indicate a strong, positive correlation between total ozone and 100-mbar stratospheric temperatures during September-March for all years, but lower ozone values at 100-mbar stratospheric temperatures colder than about [minus]60[degrees]C during the 1982-1988 period. Ozone destruction by heterogeneous photochemical processes is the main cause of ozone depletion over Syowa during the 1980's, with a lesser contribution from a change in air dynamics (heat, ozone, and momentum transport to Antarctica during the austral spring) that increased polar vortex stability, thereby promoting photochemical ozone depression within the vortex. 27 refs., 9 figs., 2 tabs.

Shigeru Chubachi (Meteorological Research Inst., Ibaraki (Japan))

1993-02-20

174

Terrestrial Spaceflight Analogs: Antarctica  

NASA Technical Reports Server (NTRS)

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.

Crucian, Brian

2013-01-01

175

Fecal Coliforms in Antarctica  

NSDL National Science Digital Library

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

Stephen C. Nold

2002-01-01

176

Antarctica as an Educational Resource  

NSDL National Science Digital Library

"As an educational resource, Antarctica is extremely broad in scope with the potential to contribute to a number of study areas," from the sciences to history, sociology, and politics. Authored by molecular biologist Clive Evans at the University of Auckland, this Web site provides a convenient resource for introducing Antarctica into the classroom and could be adapted for a range of grade levels. Luckily for life science educators, the site focuses primarily on Antarctic biology, adaptation, human impact, and the environment. Web pages contain detailed background information, as well as questions and suggested activities to stimulate discussion and help students explore the material. A more in-depth exploration of the material requires additional resources; references and Web links are provided.

177

Seismic Tomography of Erebus Volcano, Antarctica  

NASA Astrophysics Data System (ADS)

Mount Erebus (77°32'S, 167°10'E elevation 3794 meters) is the most active volcano in Antarctica and is well known for its persistent lava lake. The lake constitutes an “open window” into the conduit and underlying feeding system and offers a rare opportunity to observe a shallow convecting magmatic system. Imaging and modeling of the internal structure of Erebus volcano are best done through compiling information from arrays of seismometers positioned strategically around the volcano. From these data, the three-dimensional (3-D) structure of the conduit can be pieced together. Building this 3-D model of Erebus was a main goal of the seismic tomographic experiment Tomo Erebus (TE). During the 2007-2008 austral field season, 23 intermediate-period seismometers were installed to contribute data, through the winter, for the passive-source aspect of the experiment. One year later, 100 three-component short-period stations were deployed to record 16 chemical blasts (see Figure 1).

Zandomeneghi, Daria; Kyle, Philip; Miller, Pnina; Snelson, Catherine; Aster, Richard

2010-02-01

178

Climate and atmospheric history of the past 420,000 years from the Vostok ice core, Antarctica  

Microsoft Academic Search

The recent completion of drilling at Vostok station in East Antarctica has allowed the extension of the ice record of atmospheric composition and climate to the past four glacial-interglacial cycles. The succession of changes through each climate cycle and termination was similar, and atmospheric and climate properties oscillated between stable bounds. Interglacial periods differed in temporal evolution and duration. Atmospheric

J. R. Petit; J. Jouzel; D. Raynaud; N. I. Barkov; J.-M. Barnola; I. Basile; M. Bender; J. Chappellaz; M. Davis; G. Delaygue; M. Delmotte; V. M. Kotlyakov; M. Legrand; V. Y. Lipenkov; C. Lorius; L. Pépin; C. Ritz; E. Saltzman; M. Stievenard

1999-01-01

179

In situ radioglaciological measurements near Taylor Dome, Antarctica and implications for ultra-high energy (UHE) neutrino astronomy  

Microsoft Academic Search

Radiowave detection of the Cherenkov radiation produced by neutrino-ice collisions requires an understanding of the radiofrequency (RF) response of cold polar ice. We herein report on a series of radioglaciological measurements performed approximately 10km north of Taylor Dome Station, Antarctica from December 6, 2006–December 16, 2006. Using RF signals broadcast from: (a) an englacial discone, submerged to a depth of

D. Z. Besson; J. Jenkins; S. Matsuno; J. Nam; M. Smith; S. W. Barwick; J. J. Beatty; W. R. Binns; C. Chen; P. Chen; J. M. Clem; A. Connolly; P. F. Dowkontt; M. A. DuVernois; R. C. Field; D. Goldstein; P. W. Gorham; A. Goodhue; C. Hast; C. L. Hebert; S. Hoover; M. H. Israel; J. Kowalski; J. G. Learned; K. M. Liewer; J. T. Link; E. Lusczek; B. Mercurio; C. Miki; P. Miocinovic; C. J. Naudet; J. Ng; R. Nichol; K. Palladino; K. Reil; A. Romero-Wolf; M. Rosen; L. Ruckman; D. Saltzberg; D. Seckel; G. S. Varner; D. Walz; F. Wu

2008-01-01

180

Potential methane reservoirs beneath Antarctica.  

PubMed

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

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

2012-08-30

181

In situ radioglaciological measurements near Taylor Dome, Antarctica and implications for UHE neutrino astronomy  

Microsoft Academic Search

Radiowave detection of the Cherenkov radiation produced by neutrino-ice\\u000acollisions requires an understanding of the radiofrequency (RF) response of\\u000acold polar ice. We herein report on a series of radioglaciological measurements\\u000aperformed approximately 10 km north of Taylor Dome Station, Antarctica from\\u000aDec. 6, 2006 - Dec. 16, 2006. Using RF signals broadcast from: a) an englacial\\u000adiscone, submerged to

D. Z. Besson; J. Jenkins; S. Matsuno; J. Nam; M. Smith; S. W. Barwick; J. J. Beatty; W. R. Binns; C. Chen; P. Chen; J. M. Clem; A. Connolly; P. F. Dowkontt; M. A. DuVernois; R. C. Field; D. Goldstein; P. W. Gorham; A. Goodhue; C. Hast; C. L. Hebert; S. Hoover; M. H. Israel; J. Kowalski; J. G. Learned; K. M. Liewer; J. T. Link; E. Lusczek; B. Mercurio; C. Miki; P. Miocinovic; C. J. Naudet; J. Ng; R. Nichol; K. Palladino; K. Reil; A. Romero-Wolf; M. Rosen; L. Ruckman; D. Saltzberg; D. Seckel; G. S. Varner; D. Walz; F. Wu

2007-01-01

182

Analysis of the Mantle Transition Zone beneath West Antarctica using P-wave receiver functions  

NASA Astrophysics Data System (ADS)

Several exposed, sub-glacial, and submarine volcanoes exist throughout West Antarctica in the vicinity of the West Antarctic Rift System; prior work has suggested that a mantle plume beneath the region influences the observed rifting and volcanism. However the existence of a mantle plume has not been verified, because models from recent seismic tomography results are not well resolved at mantle transition zone depths. We use P-wave receiver functions (PRFs) from all Antarctic seismic stations installed at sites above less than 1 km of ice, including recent 2007-2012 Antarctic POLENET, permanent GSN, and the 2000-2003 TAMSEIS seismographs to explore the depth to and the thickness of the mantle transition zone beneath West Antarctica. We calculate PRFs for all earthquakes occurring at 30-90° with Mb>5.5 using a time-domain iterative deconvolution method filtered using a Gaussian-width factor of 0.5, corresponding to frequencies less than ~0.24 Hz. Using this method, we check stability of the deconvolution by convolving the vertical component with the final radial receiver function, rejecting all receiver functions that did not recover at least 80% of the original trace. Maps showing Ps pierce-points cover most of West Antarctica and the Transantarctic Mountains, with particularly good coverage beneath Marie Byrd Land and the region around Ross Island. Preliminary results for P receiver functions stacked by station and migrated to depth using the ak135 1-d velocity model indicate a depressed 410' discontinuity beneath West Antarctica; beneath the Transantarctic and East Antarctic sites, the 410' is not depressed. However, no clear depth patterns are observed for the 660' discontinuity throughout West Antarctica; at several West Antarctic sites, the 660' may even be depressed slightly. Additional work using common conversion point (CCP) stacking will enable us to more clearly map the depth of the 410' and 660' and to identify spatial variations in mantle transition zone thickness.

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

2013-12-01

183

Glacial isostatic crustal uplift in southern Victoria Land, Antarctica, from geologic and geodetic records  

NASA Astrophysics Data System (ADS)

Geologic records and geodetic measurements of glacial isostatic crustal motions are presented from the southern Victoria Land region of Antarctica. In much of the world, key records used for mapping and modeling glacial isostatic crustal motions come from raised paleoshorelines and beaches of ice-marginal lakes and seas. While such records are scarce in Antarctica, preserved paleoshorelines are present in the southern Victoria Land region of Antarctica. Light detection and ranging (LiDAR) data coverages of these features were acquired during the 2001-2002 austral summer field season by NASA's Airborne Topographic Mapper (ATM) system, resulting in 2 meter horizontal resolution digital elevation models (DEMs). This study utilizes these DEM data to derive crustal tilt values from observed changes in elevation along the length of the shorelines. Radiocarbon age data are correlated with the associated degree of shoreline tilt to derive a rate of crustal deformation since deglaciation. Modern rates of glacial isostatic crustal motion are derived from GPS stations in the same region. Campaign station occupation began in 1996-1997 under the TAMDEF (Transantarctic Mountain DEFormation Network) project, and continuous GPS data collected began in 1999 and continues under the ANET/POLENET (Antarctica Polar Earth Observing Network) project, enabling analysis of decadal scale time series. Integrated gradient curves from paleoshoreline records and GPS crustal velocities show exponential form and indicate tilting down to the east. Eastward tilt may be the result of substantial loss of East Antarctic ice, a collapsing forebulge linked to ice centers in the Ross Sea region or in interior West Antarctica, or differences in earth response due to laterally varying earth structure. Modeling of these new data, along with comparison of tilt directions to centers of ice mass loss, provide tests of these scenarios and yield new insights into earth models and ice history.

Konfal, S.; Wilson, T.; Bevis, M. G.; Kendrick, E. C.; Hall, B. L.

2011-12-01

184

Antarctica as a Martian model.  

PubMed

Previous investigators have reported that the microbiological population of the glacier free valleys of southern Victorialand, Antarctica, is sparse, and that from about 10% of the soil samples examined no micro-organisms could be cultivated. Since these areas are assumed to be more favorable to the growth of terrestrial organisms than any Martian environment, the previous authors concluded that the probability of terrestrial organisms growing on Mars would therefore be so small that sterilization standards could be relaxed by many orders of magnitude. The unsuitability of the Antarctic environment to the multiplication of terrestrial micro-organisms was ascribed by them to limiting amounts of water. We have carried out a survey of a variety of environments in the dry valleys, ranging from mountain crests to valley floors. The main purpose of our investigation was the determination of active microbial multiplication in the soil. A series of techniques was employed which permitted the detection of bacterial growth in situ. All evidence points to an active growth of micro-organisms in the Antarctic soil in all locations which we examined. The measurements were supported by electron micrographs of soil films which showed colonial growth covering soil particles. These findings suggest that Antarctica does not serve as a useful model for the Martian environment in evaluating quarantine standards. PMID:11998858

Vishniac, W V; Mainzer, S E

1973-01-01

185

Station Models  

NSDL National Science Digital Library

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

Ertl, Mr.

2007-11-03

186

Petroleum and mineral resources of Antarctica  

SciTech Connect

Following the introduction, this publication contains the following papers: (1) Are there petroleum resources in Antarctica. by John C. Behrendt; (2) Mineral occurrences of Antarctica by Peter D. Rowley, Paul L. Williams, and Douglas E. Pride; and (3) Dufek intrusion of Antarctica and a survey of minor metals and possible resources by Arthur B. Ford. The first report summarizes the information relevant to petroleum resources. Although uneconomic at present, petroleum is generally considered more likely to be exploited (if supergiant fields were ever found) in the next few decades than hard minerals. The second report reviews the reported occurrences of minerals in Antarctica and discusses their significance. The final report discusses the Dufek layered mafic intrusion, second only to the Bushveld Complex in size in the world; the Dufek intrusion might be considered as a potential target for mineral exploration. 370 references, 28 figures, 4 tables.

Behrendt, J.C. (ed.)

1983-01-01

187

Geoethical approach to mineral activities in Antarctica  

NASA Astrophysics Data System (ADS)

Antarctica is the outermost from civilization space continent. From 14.0 million km2 of surface area about 98% of Antarctica is covered by ice that averages at least 1.6 km in thickness. Geologically, the continent is the least explored in the world, and it is almost absolutely unknown what mineral resources Antarctica has as they are buried in rock that is covered by a thick ice sheet. It is thought to have large and valuable mineral deposits under the ice. This is because of what has been found in samples taken from the small areas of rock that are exposed, and also from what has been found in South Africa and South America. Up until 180 million years ago, Antarctica was a part of the Gondwanaland super continent, attached to South America, the Southern part of Africa, India and Australia, these continents then drifted apart until they reached their current positions. This leads to a possibility that Antarctica may also share some of the mineral wealth of these continents. Right now on the ice-free areas of Antarctica iron ore, chromium, copper, gold, nickel, platinum, coal and hydrocarbons have been found. The Protocol on Environmental Protection to the Antarctic Treaty, also known as the Madrid Protocol, was signed in 1991 by the signatories to the Antarctic Treaty and became law in January 1998. The Protocol provides for comprehensive protection of the Antarctic environment and associated ecosystems and includes a ban on all commercial mining for at least fifty years (this is up for review in 2041). Current climate change and melting ice in Polar Regions is opening up new opportunities to exploit mineral and oil resources. Even Antarctica's weather, ice and distance from any industrialized areas mean that mineral extraction would be extremely expensive and also extremely dangerous, the depletion of mineral recourses on the Earth can reverse banning of mining in Antarctica in future. There is no question that any resource exploitation in Antarctica will cause severe not only permanent, local impact on the environment, but also will have implications for other Earth's systems as a whole. Mineral prospecting and exploration in Antarctica need to be reflected and respected in any concept of environmental sustainability. Anyway, first stage of the geological surveying should be carried purely scientific and not designed to explore for and identify mineral deposits. It's obvious that although various countries claim sovereignty in certain regions of Antarctica, the continent should be continued to be politically neutral. Efforts of scientists and politicians should respect their own responsibility for the protection of the fragile Antarctic environment and of our planet in the whole taking care for future generations.

Talalay, Pavel

2013-04-01

188

On the Terms of Geomagnetic Daily Variation in Antarctica  

NASA Astrophysics Data System (ADS)

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

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

2009-12-01

189

Antarctica: Soils, weathering processes and environment  

SciTech Connect

Antarctica is currently the subject of world-wide interest, both because of its supposed potential for minerals, and because of its very high aesthetic and environmental values. It is therefore timely to review the current state of soil science in Antarctica, for, as is found elsewhere in the world, land management needs to be in accordance with soil attributes. The authors therefore provide background information to allow the Antarctic environment as it is related to soil formation to be understood.

Campbell, I.B.; Claridge, G.G.C.

1987-01-01

190

Galactic bursts signature in Antarctica 10 Be  

Microsoft Academic Search

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

191

Putting Antarctica on the Map  

NSDL National Science Digital Library

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

192

Space station  

NASA Technical Reports Server (NTRS)

The history of American space flight indicates that a space station is the next logical step in the scientific pursuit of greater knowledge of the universe. The Space Station and its complement of space vehicles, developed by NASA, will add new dimensions to an already extensive space program in the United States. The Space Station offers extraordinary benefits for a comparatively modest investment (currently estimated at one-ninth the cost of the Apollo Program). The station will provide a permanent multipurpose facility in orbit necessary for the expansion of space science and technology. It will enable significant advancements in life sciences research, satellite communications, astronomy, and materials processing. Eventually, the station will function in support of the commercialization and industrialization of space. Also, as a prerequisite to manned interplanetary exploration, the long-duration space flights typical of Space Station missions will provide the essential life sciences research to allow progressively longer human staytime in space.

Stewart, Donald F.; Hayes, Judith

1989-01-01

193

Transforming Neighborhoods into Family-Supporting Environments: Evaluation Issues and Challenges. Report of the Annie E. Casey Foundation's Research and Evaluation Conference (Baltimore, Maryland, March 1999).  

ERIC Educational Resources Information Center

The Annie E. Casey Foundation's fourth conference occurred as the Foundation launched a new neighborhood transformation and family development strategy centered on strengthening families. This conference summary presents discussions of the major themes from the conference. Section 1, "Understanding the Connection between Families and Communities,"…

Annie E. Casey Foundation, Baltimore, MD.

194

Seafloor spreading magnetic anomalies in the Enderby Basin, East Antarctica  

Microsoft Academic Search

The timing of the early separation of India from the contiguous Antarctica–Australia is still an unresolved problem although it is well established that Antarctica and India formed a single Indo-Antarctic platform prior to the fragmentation of eastern Gondwanaland. Inadequate age information either in the form of magnetic anomaly isochrons or dating of oceanic rocks from the conjugate margins of Antarctica

M. V. Ramana; T. Ramprasad; Maria Desa

2001-01-01

195

Concentration of trace inorganic species in surface snow along the route to Dome Fuji, Antarctica  

NASA Astrophysics Data System (ADS)

In the southern hemisphere, especially Antarctica, it is considered that ocean and stratosphere are major sources of halogen species. However, there is little data about halogen species contained in snow and ice in Antarctica. In this research, trace inorganic species (Br, Cl, F, I) in Antarctica snow 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. The quantitative analyses of elements were performed using an ion chromatograph mass spectrometer (IC-MS) and a quadrupole type inductively-coupled plasma mass spectrometer (ICP-MS). The IC-MS system consists of a single quadrupole type mass spectrometer (Agilent Technologies 6150) connected to an ion chromatograph (Dionex ICS-2000). 14 anion species including halogen species (Br-, BrO3-, CH3COO-, CH3SO3-, Cl-, C2O42-, F-, HCOO-, I-, IO3-, NO2-, NO3-, PO43-, SO42-) were analyzed by this system. The maximum concentration of Br- and I- was observed around 71°S and near 74°S on the traverse route. Average concentrations and maximum concentration of Br- were 0.2 ng/ml and 0.4 ng/ml, respectively. Average concentrations and maximum concentration of I- were 0.05 ng/ml and 0.3 ng/ml, respectively. Further results and discussion about the behavior and origin of halogen ion species in snow will be presented.

Hirabayashi, M.; Motoyama, H.

2013-12-01

196

Space analogue studies in Antarctica  

NASA Astrophysics Data System (ADS)

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

Lugg, D.; Shepanek, M.

1999-09-01

197

Space analogue studies in Antarctica  

NASA Technical Reports Server (NTRS)

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.

Lugg, D.; Shepanek, M.

1999-01-01

198

Mapping Sediment Contamination and Toxicity in Winter Quarters Bay, Antarctica  

SciTech Connect

Winter Quarters Bay (WQB) is a small embayment located adjacent to McMurdo Station, the largest researchbase in Antarctica. The bay is approximately 250 m wide andlong, with a maximum depth of 33 m. Historically, trashfrom the McMurdo Station was piled on the steep shoreline ofWQB, doused with fuel and ignited. That practice hasceased, and the adjacent land area has been regraded tocover the residual waste. The bottom of WQB remainslittered with drums, equipment, tanks, tires, cables, andother objects, especially the southeastern side of the baywhere dumping took place. Sediments are contaminated withPCBs, metals, and hydrocarbon fuels. The objectives of this study were to map the distributionof organic contaminants in WQB, assess the toxicity of WQB sediments using a simple microbial test, anddetermine correlations between toxicity and contaminantlevels. The study suggests that adverse ecological effectshave occurred from one or more of the contaminants found inWQB but the source of the toxic impacts to bay sedimentsremains unknown. Whole sediment toxicity was onlycorrelated with oil-equivalent while solvent extracts ofsediments were correlated with PAHs and oil-equivalent. Theauthors recommend that an integrated research plan bedeveloped that focuses on determining what additionalinformation is needed to make informed decisions on possibleremediation of WQB.

White, Gregory J; Crockett, Alan Bronson

2003-07-01

199

Geology of the Continental Margin of Enderby and Mac. Robertson Lands, East Antarctica: Insights from a Regional Data Set  

Microsoft Academic Search

In 2001 and 2002, Australia acquired an integrated geophysical data set over the deep-water continental margin of East Antarctica from west of Enderby Land to offshore from Prydz Bay. The data include approximately 7700 km of high-quality, deep-seismic data with coincident gravity, magnetic and bathymetry data, and 37 non-reversed refraction stations using expendable sonobuoys. Integration of these data with similar

H. M. J. Stagg; J. B. Colwel; N. G. Direen; P. E. O’Brien; G. Bernardel; I. Borissova; B. J. Brown; T. Ishirara

2004-01-01

200

Antarctica: Challenging Forecasts for a Challenging Environment  

NSDL National Science Digital Library

Antarctica: Challenging Forecasts for a Challenging Environment features two educational pieces. The first is the overview giving the general audience a broad look at Antarctica including some history, interesting facts, real-life experiences, climate, and the challenges inherent to this frozen continent. The second is the main presentation where experts in Antarctic research and forecasting, share their knowledge of the continent. They discuss forecasting challenges as well as present and future research topics while providing elaborations on the uniqueness in Antarcticaâs location, topography, and forecasting techniques as compared to other parts of the globe.

Comet

2007-08-14

201

The Bess-Polar II Long Duration Flight Above Antarctica  

NASA Technical Reports Server (NTRS)

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 11) 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.

Sasaki, Makoto; Yamamoto, Akira; Yoshimura, Koji; Makida, Yasuhiro; Matsuda, Shinya; Hasegawa, Masaya; Horikoshi, Atsushi; Tanaka, Ken-ichi; Suzuki, Junichi; Nishimura, Jun; Sakai, Ken-ichi; Shinoda, Ryoko; Orito, Reio; Matsukawa, Yosuke; Kusumoto, Akira; Yoshida, Tetsuya; Fuke, Hideyuki; Mitchell, John W.; Streitmatter, Robert E.; Hams, Thomas; Sasaki, Makoto; Seo, Eun-suk; Lee, Moo-hyon; Kim, Ki-chun; Thakur, Needharika

2008-01-01

202

The BESS-Polar II Long Duration Flight above Antarctica  

NASA Astrophysics Data System (ADS)

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.

Sasaki, Makoto

203

Gongguan Metro Station NTU Hospital Metro Station  

E-print Network

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

Hung, Shih-Hao

204

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

NASA Astrophysics Data System (ADS)

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

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

2011-12-01

205

Fossils in Antarctica: British Antarctic Survey  

NSDL National Science Digital Library

Although marching penguins add to Antarctica's allure, The British Antarctic Survey (BAS) has found fossil evidence that dinosaurs, marsupials, and forests inhabited the area long before penguins charmed the world with their trademark waddle. Since 1940, when the fossil collection of the BAS was started, it has grown to 40,000 specimens. The "Fossils" section of the BAS website can be found on the left side of the homepage in the "About Antarctica" area, and is divided into two explanatory sections: "Fossils from the Antarctic" and "Fossil Locations in Antarctica". There are also links in each section, near the top right hand corner of the page, to "Type and Figured Fossil Collection" and "Fossils Picture Gallery". In the "Fossils from the Antarctic" section, the types of fossils found are explained and include: molluscs, arthropods, echinoderms and plants. The "Fossil Locations in Antarctica" section has a map of the three islands where a large amount of fossils have been found, along with descriptions of each island and what general types of fossils have been found on them.

206

Zinc-cobalt colimitation of Phaeocystis antarctica  

Microsoft Academic Search

We present evidence demonstrating the capability of Phaeocystis antarctica colonies to substitute cobalt (Co) and zinc (Zn) as micronutrients, in which Co limitation is alleviated by additions of Zn and vice versa. Maximal growth rates and biomass were determined by fluorescence and the values obtained under replete Zn and no added Co conditions were significantly higher than under replete Co

Mak A. Saito; Tyler J. Goepfert

2008-01-01

207

Groenlandaspis in Antarctica, Australia and Europe  

Microsoft Academic Search

Groenlandaspis is a member of the Arthrodira, a group of Devonian armoured fishes. In the past Groenlandaspis has been found only in eastern Greenland but now Alexander Ritchie has recognised at least six species from sites in Greenland, Europe, Australia and Antarctica. His account demonstrates that these arthrodires enjoyed a very wide geographical distribution during the Upper Devonian and that

Alexander Ritchie

1975-01-01

208

Antarctica: What Shall We Do with It?  

ERIC Educational Resources Information Center

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

Branson, Margaret S.; Long, Cathryn J.

1977-01-01

209

Antarctica--the Ultimate Summer Institute.  

ERIC Educational Resources Information Center

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

Van Wey, Nate J.

1995-01-01

210

CyberHunt: Head Off to Antarctica.  

ERIC Educational Resources Information Center

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

Kloza, Brad

2001-01-01

211

Glacial Earthquakes in Greenland and Antarctica  

E-print Network

, but they exhibit several characteristics similar to glacial earthquakes in Greenland. 467 Annu.Rev.EarthPlanetGlacial Earthquakes in Greenland and Antarctica Meredith Nettles and G¨oran Ekstr¨om Lamont@ldeo.columbia.edu Annu. Rev. Earth Planet. Sci. 2010. 38:467­91 First published online as a Review in Advance on February

Jellinek, Mark

212

Read--and Walk--to Antarctica  

ERIC Educational Resources Information Center

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

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

2012-01-01

213

Lystrosaurus zone (triassic) fauna from antarctica.  

PubMed

Tetrapod skeletons recently found in the Fremouw Formation in the Shackleton Glacier area, Transantarctic Mountains, include several forms that closely compare to South African species. Faunal similarities that confirm a close connection between Antarctica and Africa during the Triassic Period lend further support to the concept of Gondwanaland and continental drift. PMID:17755654

Kitching, J W; Collinson, J W; Elliot, D H; Colbert, E H

1972-02-01

214

Lystrosaurus Zone (Triassic) Fauna from Antarctica  

Microsoft Academic Search

Tetrapod skeletons recently found in the Fremouw Formation in the Shackleton Glacier area, Transantarctic Mountains, include several forms that closely compare to South African species. Faunal similarities that confirm a close connection between Antarctica and Africa during the Triassic Period lend further support to the concept of Gondwanaland and continental drift.

James W. Kitching; James W. Collinson; David H. Elliot; Edwin H. Colbert

1972-01-01

215

Which Map's the Best Map for Antarctica?  

NSDL National Science Digital Library

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

216

The Stable Isotopes of Atmospheric Methane: Long-Term Observations at Alert (Canada) and Neumayer (Antarctica)  

Microsoft Academic Search

Ten years records of CH4 concentration, 13C\\/12C-CH4 and 2H\\/H-CH4 from the background stations Alert, Arctic, (82.45° N) and Neumayer, Antarctica, (70.65° S) are presented. High volume integrated (Alert) and spot (Neumayer) samples are collected at the respective sites and are analysed in Heidelberg using GC-FID technique for mixing ratios, IRMS for 13C\\/12C and 2H\\/H ratios, and, in the last two

C. Poss; C. Veidt; D. E. Worthy; I. Levin

2003-01-01

217

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.

218

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

NASA Astrophysics Data System (ADS)

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.

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

219

Geodetic GNSS measurements as a basis for geodynamic and glaciological research in Antarctica  

NASA Astrophysics Data System (ADS)

For about twenty years our institute has been carrying out geodetic GNSS measurements and has been actively working in international collaboration for Antarctic research. Episodic GPS (and later GNSS) measurements of all contributing nations enter the "Database of the SCAR Epoch Crustal Movement Campaigns" which is being maintained at the institute in the framework of SCAR-GIANT. GNSS measurements form a basis for the realization of the International Terrestrial Reference Frame (ITRF) and its densification in Antarctica. Linked to respective products of an ongoing activity to re-process GNSS data of globally distributed stations a consistent and precise TRF realization can be reached. We will give an overview on the latest developments and the subsequent applications for geodynamic and glaciological investigations in Antarctica. Complementary to continuous GNSS observations episodic GNSS measurements have the potential to provide independent data on vertical deformations, which can be used to investigate the present-day ice-mass balance and to refine models of the glacial-isostatic adjustment. Repeated and properly referenced GNSS measurements at the ice surface yield ice-flow velocities and local ice-surface height changes. We will present latest results, e.g. for the Amundsen Sea sector, the subglacial Lake Vostok region and near-coastal regions of Dronning Maud Land or Enderby Land. Thus, it will be discussed how geodetic GNSS measurements form an important and indispensable basis for geodetic Earth system research with the focus on Antarctica.

Scheinert, Mirko; Dietrich, Reinhard; Knöfel, Christoph; Fritsche, Mathias; Rülke, Axel; Schröder, Ludwig; Richter, Andreas; Eberlein, Lutz

2013-04-01

220

Continuous high-temporal resolution black carbon ice core records from Antarctica  

NASA Astrophysics Data System (ADS)

The Antarctic ice cap is a unique vantage point from which to observe the global background of black carbon aerosol (BC). Far removed from sources, BC in the Antarctic atmosphere is largely due to biomass burning at low- to mid-latitudes modulated by upper tropospheric (and perhaps stratospheric) transport, climate variability and human activity. BC aerosols have been investigated at several locations in Antarctica including the coastal stations Halley, Syowa and Neumayer, Amundsen-Scott at the South Pole and the South Shetland islands north of the Antarctic Peninsula. Beyond these time series little is known regarding the history of BC over Antarctica. Pioneering research by Petr Chylek demonstrated that it was possible to develop BC records from Antarctic ice cores, albeit with great difficulty and at low temporal resolution. We have recently developed an extremely sensitive analytical method capable of determining BC in Antarctic ice cores at sub annual resolution. This method has allowed us to build upon the research of Chylek and reconstruct BC deposition to Antarctica over the past 200 years at ~ monthly time scales. These "new- generation" records will be presented and the extent of which they reflect large scale BC aerosol variability discussed.

Edwards, R.; McConnell, J. R.; Aristarain, A. J.; Curran, M. A.; Pedro, J.; Cataldo, M.; Evangelista, H.

2008-12-01

221

Observation Station  

ERIC Educational Resources Information Center

This article describes how a teacher integrates science observations into the writing center. At the observation station, students explore new items with a science theme and use their notes and questions for class writings every day. Students are exposed to a variety of different topics and motivated to write in different styles all while…

Rutherford, Heather

2011-01-01

222

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

NASA Astrophysics Data System (ADS)

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

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

2008-05-01

223

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

Code of Federal Regulations, 2010 CFR

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

2010-10-01

224

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

Code of Federal Regulations, 2014 CFR

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

2014-10-01

225

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

Code of Federal Regulations, 2012 CFR

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

2012-10-01

226

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

Code of Federal Regulations, 2013 CFR

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

2013-10-01

227

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

Code of Federal Regulations, 2011 CFR

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

2011-10-01

228

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

NASA Astrophysics Data System (ADS)

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

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

2012-04-01

229

Norwegian-United States IPY Science Traverse in East Antarctica: Route Planning and Firn Temperature Investigation  

NASA Astrophysics Data System (ADS)

In austral summers of 2007-2008 and 2008-2009, Norway and the United States will conduct a collaborative traverse in Dronning Maud Land, East Antarctica. The objective of the traverse is to obtain field measurements (ice cores, snow pits, AWS's, firn temperatures, GPR profiling) that will aid us in advancing our understanding of climate variability of a vast yet under-explored sector of Antarctica and its roll in the global climate system. University of Colorado will assist the traverse route planning using remote sensing and conduct a study of multi-decadal scale climate change using firn temperature measurements. In the first season, the traverse will leave from Norwegian Troll Station (72° S, 2.5° E), and end at Amundsen-Scott Station at the South Pole, visiting Plateau (72.3° S, 40.5° E) and Pole of Inaccessibility (83.8° S, 65.8° E), sites of now abandoned stations. The first-season traverse will connect these four locations, the distance totaling to about 2500 km. Second-season traverse, from South Pole to Troll, will take a different route near the western edge of the Dronning Maud Land. The duration of both traverses is around 80 days including stops for ice coring and setting up AWS's etc. Details of routes and sites of scientific tasks are decided upon examinations of MOA (Mosaic of Antarctica) and RAMP (Radarsat Antarctic Mapping Project) images. Megadune fields and blue ice areas are identified in images that are of interest for studies of snow accumulation variations and interaction of local topography with the atmosphere. The firn temperature investigation aims at obtaining reliable surface temperature trend in multi-decadal to century scale in the interior of Antarctica. Our approach is to monitor temperature changes at several discrete depths in the firn over an extended period of time. This provides a time-series of the borehole temperature profile. Simulations by simple heat transfer model with artificial surface temperature history show that the trend of several tens of degrees (~0.5° C) per century is detectable with well-calibrated PRT's (Platinum Resistance Thermometers) placed at the depth of around 50 ~ 60 m and monitored over 1 ~ 2 years. Further, careful monitoring of intermediate depths (10 ~ 30 m) will help to discriminate between inter-annual to decadal scale variations and longer-term trends. We will set up at least four automated firn temperature recording systems with 10 to 12 PRT's distributed over the upper 50 to 60 m in the firn, together with standard AWS data at sites. Data will be transmitted multiple times per day by a satellite system (ARGOS).

Muto, A.; Scambos, T.

2006-12-01

230

PERSPECTIVE How committed are we to monitoring human impacts in Antarctica?  

NASA Astrophysics Data System (ADS)

Under the Antarctic Treaty System, environmental monitoring is a legal obligation for signatory nations and an essential tool for managers attempting to minimize local human impacts, but is it given the importance it merits? Antarctica is a vast frozen continent with an area around 1.5 times that of Europe (14 000 000 km2), but the majority of its terrestrial life is found on multiple outcrops or 'islands' of ice-free coastal ground, with a combined area of ~6000 km2, equivalent to four times that of Greater London (Tin et al 2009). The biological communities of these ice-free terrestrial habitats are dominated by a small number of biological groups, primarily mosses, lichens, microinvertebrates and microorganisms. They include many endemic species, while birds and marine mammals use coastal areas as breeding sites (Chown and Convey 2007). Figure 1 Figure 1. Map of the Antarctic Treaty area (south of latitude 60°S) showing the locations of year-round and seasonal stations built on rock or permanent ice (i.e. ice sheets or ice shelves). Data on station locations were taken from the Council of Managers of National Antarctic Programs website (COMNAP 2010). There is evidence to suggest that although these stations are registered on the COMNAP list, a number of stations are not regularly occupied or in use (see United Kingdom et al 2006, p 9). Since the influx of national scientific research programmes and infrastructure that accompanied the International Geophysical Year (1957-1958), Antarctica's habitats have been encroached upon increasingly by human activities. Over 120 research stations have been built (~75 currently operational) with the great majority located on ice-free coastal ground to allow ease of access by ship. (Headland 2009, COMNAP 2010). Construction of cargo and personnel landing and handling facilities, station buildings, airport infrastructure, roads and fuel storage areas have, to varying degrees, destroyed native vegetation and terrestrial fauna and displaced bird and marine mammals from breeding sites in their immediate environment. An early history of poor environmental management and waste disposal practices around many stations has left a legacy of fuel-contaminated ground and abandoned waste sites in adjacent marine and terrestrial environments (Tin et al 2009). Construction of research stations and other infrastructure fulfils two national objectives: (1) supporting geopolitical aspirations of claimant nations and (2) demonstrating a significant commitment to undertaking science in Antarctica, which is a prerequisite for attaining consultative status at the Antarctic Treaty Consultative Meeting. However, these objectives may not be supported equally, with little or no science performed routinely at some stations (United Kingdom et al 2006). In addition, co-ordination of science activities between nations—another aspiration under the Antarctic Treaty—is often lacking, leading to duplication of research between national programmes, and even that undertaken at nearby stations. In some cases, components of national research programmes lack any international, open or objective assessment of quality. Nevertheless, new nations continue to become involved in Antarctic affairs, and almost inevitably seek to establish their own infrastructure, while some established Treaty Parties continue to further expand their existing logistic and infrastructure footprints. Despite calls for nations to share existing infrastructure or reuse abandoned stations (ATCM 2006), new stations continue to be constructed on pristine sites, with the Antarctic terrestrial environment in particular coming under increased pressure. The Protocol on Environmental Protection to the Antarctic Treaty (commonly known as the Environmental Protocol), which came into force in 1998, sets out common minimum standards for environmental management by all Antarctic Treaty Parties. Under the Protocol, it is mandatory to regularly monitor the environmental impacts caused by any new infrastructure that requires the completion of a Comprehensive E

Hughes, Kevin A.

2010-12-01

231

Planetary geomorphology field studies: Iceland and Antarctica  

NASA Technical Reports Server (NTRS)

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

Malin, M. C.

1984-01-01

232

Presence and distribution of persistent toxic substances in sediments and marine organisms of Potter Cove, Antarctica.  

PubMed

Levels of butyltin compounds, polychlorinated biphenyls, and heavy metals were analyzed in marine sediments and organisms (Notothenia coriiceps, Laternula elliptica, and Nacella concinna), each of which has a different feeding strategy, in Potter Cove, Antarctica. PCBs were lower than detection limits in all samples. Only butyltin compounds were detected in a restricted area near the scientific station. Chromium, copper, magnesium, lead (Pb), and zinc had similar behavior in the cove, probably because they are regulated by similar process and conditions. However, Pb levels in some sites of the cove seem to be related to human activities in the area. Cadmium levels were relatively low, with the highest values found close to the shoreline, which is probably influenced by seasonal streams draining waters from Potter Peninsula. Results showed that despite the fact that Jubany Station has been operating for > 50 years, surface sediment and biota from Potter Cove do not exhibit levels of pollutants representing environmental concern. PMID:20379707

Curtosi, Antonio; Pelletier, Emilien; Vodopivez, Cristian; St Louis, Richard; Mac Cormack, Walter Patricio

2010-11-01

233

THE GENUS SARCOGYNE ( ACAROSPORACEAE ) IN ANTARCTICA  

Microsoft Academic Search

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

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

1998-01-01

234

Can increasing CO2 cool Antarctica?  

NASA Astrophysics Data System (ADS)

CO2 is the strongest anthropogenic forcing agent for climate change since pre-industrial times. Like other greenhouse gases, CO2 absorbs terrestrial surface radiation and causes emission from the atmosphere to space. As the surface is generally warmer than the atmosphere, the total long-wave emission to space is commonly less than the surface emission. However, this does not hold true for the high elevated areas of central Antarctica. Our investigations show, that for the high elevated areas of Antarctica the greenhouse effect (GHE) of CO2 is commonly around zero or even negative. This is based on the quantification of GHE as the difference between long-wave surface emission and top of atmosphere emission. We demonstrate this behaviour with the help of three models: a simple two-layer model, line-by-line calculations, and an ECMWF experiment. Additionally, in this region an increase in CO2 concentration leads to an instantaneous increased long-wave energy loss to space, which is a cooling effect on the earth-atmosphere system. However, short-wave warming by the weak absorption of solar radiation by CO2 are not taken into account here. The reason for this counter-intuitive behaviour is the fact that in the interior of Antarctica the surface is often colder than the stratosphere above. Radiation from the surface in the atmospheric window emitted to space is then relatively lower compared to radiation in the main CO2 band around 15 microns, which originates mostly from the stratosphere. Increasing CO2 concentration leads to increasing emission from the atmosphere to space, while blocking additional portions of surface emission. If the surface is colder than the stratosphere, this leads to additional long-wave energy loss to space for increasing CO2. Our findings for central Antarctica are in strong contrast to the generally known effect that increasing CO2 has on the long-wave emission to space, and hence on the Antarctic climate.

Schmithuesen, Holger; Notholt, Justus; König-Langlo, Gert; Lemke, Peter

2014-05-01

235

Life on ice, Antarctica and Mars  

NASA Technical Reports Server (NTRS)

The study of the origin of life and the prospects for human exploration of Mars are two themes developed in a new 57-minute film, Life on Ice, Antarctica, and Mars, produced by the InnerSpace Foundation and WHRO Television for broadcast by the Public Broadcasting System (PBS). A brief explanation of the film and how it relates to the future human exploration of space is presented.

Anderson, D. T.; Mckay, C. P.; Wharton, Robert A., Jr.; Sagan, C.; Squyres, S. W.; Simmons, G. M.

1991-01-01

236

Springtime stratospheric NO2 in Antarctica  

Microsoft Academic Search

We present springtime measurements of column amounts of stratospheric nitrogen dioxide measured by ground based absorption spectroscopy from Scott Base, Antarctica (77.8°S, 166.7°E). There is a rapid build up from <1 × 1015 molecules cm?2 at the end of August to about 5 × 1015 molecules cm?2 by mid October. The period covered is the transition time between winter night,

R. L. McKenzie; P. V. Johnston

1984-01-01

237

Tohoku Tsunami Created Icebergs In Antarctica  

NSDL National Science Digital Library

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.

Patrick Lynch

238

Analysis of continuous GPS measurements from southern Victoria Land, Antarctica  

USGS Publications Warehouse

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.

Willis, Michael J.

2007-01-01

239

Meteorological data for the astronomical site at Dome A, Antarctica  

E-print Network

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...

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

2014-01-01

240

LiDAR in extreme environment: surveying in Antarctica  

NASA Astrophysics Data System (ADS)

This study was performed under the patronage of the Italian National Research Programme in Antarctica (PNRA) with the aim to realize a high resolution Digital Elevation Model (DEM) of the moraine named "Boulder Clay" which insists approximately 7 km far from the Italian Research Base "Mario Zucchelli Station" in the Terra Nova Bay area. The DEM will be included in the project for the construction of two runways to be used as support facilities for the scientific research campaigns which take place on regular basis each year. Although the research efforts to realize a detailed cartography of the area is on-going, for the specific aim and urgency of this project it was decided to perform a laser scanning survey in this extreme environment in order to obtain contour lines describing the terrain elevation each 50 cm and volume analysis. The final result will be super imposed on a photogrammetric DEM with contour lines each 2.5 m and satellite images. This paper focus both on the final scientific data and on all the challenges have to be faced in such extreme and particular environment during the laser scanning survey.

Abate, D.; Pierattini, S.; Bianchi Fasani, G.

2013-10-01

241

Anthropogenic and natural disturbances to marine benthic communities in Antarctica  

SciTech Connect

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.

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

1995-05-01

242

Monitoring of nitrogen dioxide, ozone and halogens radicals in Antarctica  

NASA Astrophysics Data System (ADS)

Monitoring of atmospheric compounds at high latitudes is a key factor for a better understanding of the processes driving the chemical cycles of ozone and related chemical species. In this frame, the GASCOD (Gas Analizer Spectrometer Correlating Optical Differences) equipment is installed at the Mario Zucchelli Station (MZS - 74.69S, 164.12E) since December 1995, carrying out observations of nitrogen dioxide (NO2) and ozone (O3). The recent advances in sensor technologies and processor capabilities, suggested the setup of a new equipment, based on the same optical layout of the 'old' GASCOD , with enhanced performances and improved capabilities for the measurements of solar radiation in the UV-visible spectral range (300-700nm). The efforts accomplished, allowed for the increase of the investigated tracers. Actually, mainly due to the enlargement of the covered spectral range and to the adoption of a CCD sensor, in addition to the NO2 and O3 compounds, others species can be monitored with the new instrumental setup such as bromine, chlorine and iodine oxides (BrO, OClO and IO). The innovative equipment called GASCODNG (GASCOD New Generation) was installed at MZS during the 2012/2013 Italian Antarctic expedition, in the framework of the research projects SAMOA (Automatic Station Monitoring Antarctic Ozonosphere) and MATAGRO (Monitoring Atmospheric Tracers in Antarctica with Ground Based Observations) funded by the Italian and Portuguese Antarctic programs respectively. In this paper a brief description of the new equipment is provided, highlighting the main improvements with regard to the 'old' one. Furthermore the full dataset (1996 - 2012) of NO2 total columns, obtained with the GASCOD installed at MZS, is compared with the data obtained with satellite borne equipments (GOME, SCIAMACHY, OMI and GOME2) and the main statistical parameters are analyzed and discussed in detail.

Bortoli, Daniele; Ravegnani, Fabrizio; Costa, Maria J.; Genco, Silvia; Kulkarni, Pavan K.; Mendes, Rui; Domingues, Ana Filipa; Anton, Manuel; Giovanelli, Giorgio; Silva, Ana Maria

2013-10-01

243

Infrasound Observations at the Lützow-Holm Bay region, East Antarctica  

NASA Astrophysics Data System (ADS)

Characteristic infrasound waves observed at Antarctic stations demonstrate physical interaction involving surface environmental changes in the continent and surrounding oceans. A Chaparral type infrasound sensor was installed at Syowa Station (SYO; 39E, 69S), East Antarctica, as one of the projects of the International Polar Year (IPY2007-2008). Continuous recording data during the three seasons in 2008-2010 clearly indicate a contamination of the background oceanic signals (microbaroms) with peaks between 4 and 10 s observed during a whole season. The peak amplitudes of the microbaroms has relatively lower amplitudes during austral winters, caused by a larger amount of sea-ice extending around the Lützow-Holm Bay near SYO, with decreasing ocean wave loading effects. Microbaroms measurements are a useful tool for characterizing ocean wave climate, complementing other oceanographic and geophysical data. In the austral summer in 2013, a few number of infrasound stations was established along the coast of LHB. Two different size of infrasound arrays were installed at SYO (100m spacing triangle) and S16 area on the continental ice sheet (1000m spacing triangle). In addition, isolated single stations were developed at two outcrops along the LHB. The new two infrasound arrays clearly detected the microbaroms with their propagating directions from the Southern Ocean. Moreover, characteristic signals associated with calving of the edge of glaciers, as well as the shock waves generated from meteorite injection at the Russian Republic on 15 February 2013. In this presentation, several kind of remarkable data are demonstrated. Detail measurements of the infrasound waves in Antarctica could be a new proxy for monitoring a regional environmental change together with temporal climate variations in polar region.

Kanao, M.; Murayama, T.; Yamamoto, M.; Ishihara, Y.; Kakinami, Y.

2013-12-01

244

Unprecedented upper-air dropsonde observations over Antarctica from the 2010 Concordiasi Experiment: Validation of surface-based inversions from ERA-Interim and Satellite data  

NASA Astrophysics Data System (ADS)

The 2010 Concordiasi field experiment took place over Antarctica from September to December, 2010. During Concordiasi, for the first time, thirteen NCAR Driftsonde systems were launched from McMurdo station, ascended to the stratosphere, and then drifted with the winds. The Driftsonde provides a unique platform to release dropsondes that measure the atmosphere from the lower stratosphere to the surface in otherwise difficult to reach parts of the globe. A total of 639 soundings were obtained and provided unprecedented high quality profiles over Antarctica. Surface-based inversions (SBIs), where atmospheric temperature increases with height from the surface, occur very frequently over Antarctica. The SBIs play an important role in Antarctic climate. Much less is known about the characteristics of the SBIs over Antarctica than the Arctic. With the exception of the South Pole station, all Antarctic operational radiosonde stations are located along the coast, so there are hardly any in-situ upper air observations over the Antarctic interior. This study uses the SBI properties derived from Concordiasi high-resolution dropsonde and radiosonde data to study SBI variability and validate SBI properties from ERA-Interim reanalysis products and products from two hyper-spectral satellite instruments, the Advanced InfraRed Sounder (AIRS) and Infrared Atmospheric Sounding Interferometer (IASI). All of these three products are operational and available over the entire Antarctic region, and have high vertical resolution to resolve the SBIs, but need to be validated. Preliminary analysis concludes that the dropsonde data captures the main features of SBIs over Antarctica found by previous studies, more frequent, deeper and more intensive SBIs over the continent than over the surrounding ocean. If the three operational products are validated, they will be used to study SBI variability beyond the time period of Concordiasi, including evaluating long-term trends.

Cohn, S. A.; Wang, J.; Boylan, P.

2013-12-01

245

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

NASA Astrophysics Data System (ADS)

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.

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

2012-12-01

246

Sky Station  

NSDL National Science Digital Library

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

1997-01-01

247

Tracking the sources and sinks of Antarctica's subglacial waterways  

NASA Astrophysics Data System (ADS)

Deep beneath Antarctica's kilometers-thick layer of glacial ice is a complex network of rivers and lakes. Research suggests that this water may affect the flows of the southern continent's massive ice streams, though the nature of its effect remains unclear. Adding to scientists' understanding of Antarctica's subglacial hydrology, Christoffersen et al. studied five ice streams that flow into the Ross Sea.

Schultz, Colin

2014-09-01

248

Rock glaciers in the South Shetland Islands, Western Antarctica  

Microsoft Academic Search

Rock glaciers are found in the peripheral regions of Antarctica particularly in the Antarctic Peninsula region. Study of these features is relevant for the palaeoenvironmental reconstruction of maritime Antarctica because they are indicators of permafrost and periglacial conditions. This paper reports and analyzes the results of an inventory of rock glaciers and protalus lobes in the South Shetland Islands. Nine

Enrique Serrano; Jerónimo López-Mart??nez

2000-01-01

249

Antarctica: King of Cold: Grades 2-3: Illustrated Book  

NSDL National Science Digital Library

This informational text explains that while both the Arctic and Antarctica are cold, Antarctica is much colder and drier - a polar desert. The text is written at a grade two through grade three reading level. This version is a full-color PDF that can be printed, cut and folded to form a book. Each book contains color photographs and illustrations.

Fries-Gaither, Jessica

250

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 ...

251

Birth of a Large Iceberg in Pine Island Bay, Antarctica  

NSDL National Science Digital Library

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 images were acquired by the MISR instrument onboard NASA's Terra spacecraft.

2012-12-06

252

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

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

253

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

NASA Astrophysics Data System (ADS)

The capability of the GPS in retrieving the precipitable water vapour (PWV) content at low- and mid-latitudes has been amply investigated by several studies. In Polar Regions, beyond the classical positioning application, the use of GPS observations for sensing the atmosphere is of particular interest due to its easy and unmanned operability. It is well known that, in those areas, the atmospheric water vapour content is approximately one third or less than that present at mid latitudes and that on the Antarctic Plateau the PWV drops down to less than a few mm. As a consequence, the use of GPS data in sensing the atmosphere can be reliably applied only on coastal areas, were the PWV is large enough to exceed the sensitivity of the method. Radio-soundings are periodically performed at several coastal Antarctic stations, where permanent GPS equipments are also installed. The co-location of GPS and radio-soundings allows a validation of the PWV derived from the geodetic data. In this investigation we present the results of the analysis of continuous long time series of GPS data acquired at Mawson (MAW1), Casey (CAS1), Davis (DAV1), McMurdo (MCM4) and Mario Zucchelli (TNB1) stations during twelve years spanning 1999-2010. Particularly, at each site, the PWV is determined with GPS data and the same parameter derived from the analysis of the radio-sounding is used for validation. The GPS analysis is optimized for Antarctic data, using specific atmospheric models (e.g. the Vienna Mapping Function) and particular care in the data screening and elimination. The sites to be analyzed were selected according to the radiosonde equipment: the Vaisala sensors' readings were corrected specifically with ad hoc models.

Negusini, M.; Sarti, P.; Tomasi, C.; Petkov, B.

2012-12-01

254

Which Map's the Best Map for Antarctica?  

NSDL National Science Digital Library

With Antarctica as the focus, this weeklong unit provides an in-depth look at the attributes of different map types. Throughout the unit, students collect their findings in a portfolio. A set of teacher tools are provided, including downloadable readings, daily breakdowns of tasks, teacher strategies for using the activities, a portfolio grading sheet, and a project rubric sheet. An online activity is provided in which students study how latitude and longitude are used in map creation, the different types of map projections. A student handout with guidance for putting together their portfolios and examples of creative final projects is also available.

255

Antarctica: measuring glacier velocity from satellite images  

SciTech Connect

Many Landsat images of Antarctica show distinctive flow and crevasse features in the floating part of ice streams and outlet glaciers immediately below their grounding zones. Some of the features, which move with the glacier or ice stream, remain visible over many years and thus allow time-lapse measurements of ice velocities. Measurements taken from Landsat images of features on Byrd Glacier agree well with detailed ground and aerial observations. The satellite-image technique thus offers a rapid and cost-effective method of obtaining average velocities, to a first order of accuracy, of many ice streams and outlet glaciers near their termini.

Lucchitta, B.K.; Ferguson, H.M.

1986-11-28

256

Exhumation of the Shackleton Range, Antarctica  

NASA Astrophysics Data System (ADS)

The Shackleton Range is situated between 80° - 81°S and 19° - 31°W, where it forms the continuation of the Transantarctic Mountains in the Weddell Sea sector of Antarctica. There, Precambrian igneous and metamorphic basement is overlain by (meta-) sedimentary rocks of an Early Paleozoic nappe stack and post-orogenic red beds. Nappe stacking resulted from the collision of East and West Gondwana due to the closure of the Mozambique Ocean in pan-African times. The uplift and exhumation history of the Shackleton Range has been analysed earlier based on a series of vertical fission track profiles (Schäfer, 1998; Lisker et al., 1999). Zircon ages range from ~160 to 210 Ma while apatite ages between ~95 and ~170 Ma comprise a break in slope of the altitude regression at ~110 Ma, and are accompanied by mean track lengths of 12.7 - 14.1 µm (standard deviation 1.0 - 1.4 µm). These data have been interpreted qualitatively in terms of two cooling/ exhumation stages during Jurassic and mid-Cretaceous times. However, the recognition of Jurassic volcaniclastic rocks associated with the ~180 Ma Ferrar event in the vicinity of the sample locations (Buggisch et al., 1994) challenges this exhumation concept. Moreover, new fission track proxy data (Dpar) and apatite (U-Th-Sm)/He ages between 88 and 171 Ma allow thermal history modelling of the combined thermochronological data. First tentative thermal history models suggest early Mesozoic cooling followed by (post-) Jurassic heating and final cooling since the Late Cretaceous. This scenario requires burial of the Shackleton Range region, and therefore the existence of a sedimentary basin at least during the Jurassic-Early Cretaceous, and subsequent basin inversion. The thickness of the now vanished sedimentary strata did unlikely exceed 2 - 3 km. Future work including additional apatite fission track analyses will help to quantifying geometry, depth and timing of this depocentre and evaluating potential links with the coeval basin (system) along the Transantarctic Mountains and/ or similar settings in Dronning Maud Land (e.g., the Heimefrontfjella). References: Buggisch, W., Kleinschmidt, G., Höhndorf, A. and Pohl, J., 1994, Stratigraphy and Facies of Sediments and Low-Grade Metasediments in the Shackleton Range, Antarctica. Polarforschung, 63: 9-32. Lisker, F., Schäfer, T. and Olesch, M., 1999, The Uplift/Denudation History of the Shackleton Range (Antarctica) Based on Fission-Track Analyses. Terra Antarctica, 6: 345-352. Schäfer, T., 1998, Thermo-tektonische Entwicklung von Oates Land und der Shackleton Range (Antarktis) basierend auf Spaltspur-Analysen. Berichte zur Polarforschung, 263: 107 p.

Lucka, Nicole; Lisker, Frank; Läufer, Andreas; Spiegel, Cornelia

2013-04-01

257

Aerospace crew station design  

NASA Technical Reports Server (NTRS)

Consideration is given to spacecraft cockpits and work stations, commercial aircraft cockpits and crew stations, high performance aircraft cockpits and crew stations, and space stations and habitat crew stations. Particular attention is given to an historical review of NASA manned spacecraft crew stations, ESA spacelab crew stations, the evolution of commercial aircraft flight station design, Boeing 757/767 flight deck, a historical review of Concorde flight deck design, trends in the cockpit design of new European fighters, and state-of-the-art applications for Space Station crew interface design.

Carr, Gerald P. (editor); Montemerlo, Melvin D. (editor)

1984-01-01

258

M Station, Austin  

E-print Network

Station 9081 108 ID LL SS WE EA MR EQ AE LEED Platinum (Standard) LEED Platinum (M Station) M Station 9081 10849 $0.00/sf Planning ID LL SS WE EA MR EQ AE LEED Platinum (Standard) LEED Platinum (M Station) M Station 9081 10849 $0.00/sf... Planning Location ID LL SS WE EA MR EQ AE LEED Platinum (Standard) LEED Platinum (M Station) M Station 9081 10849 $0.00/sf Planning Location Transportation ID LL SS WE EA MR EQ AE LEED Platinum (Standard) LEED Platinum (M Station) M Station...

Mathon, S.

2011-01-01

259

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.

260

Cenozoic motion between East and West Antarctica  

PubMed

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

Cande; Stock; Muller; Ishihara

2000-03-01

261

Galactic bursts signature in Antarctica 10Be  

E-print Network

I detected a very strong (25 %var) period of 3592+-57 years at 99% confidence level in the 10Be deposition rates from Vostok, Antarctica ice core raw (gapped, unaltered) data. The period was verified at 99% confidence level against the 10Be concentration raw data at both Vostok, as 3700+-57 years at very strong 38 %var, and Taylor Dome, Antarctica, as 3800+-61 years at very strong 23 %var. The noisy Mg concentration data from Taylor Dome also show an extremely strong (44 %var) period of 3965+-16 years. The Vostok data also show the Hallstadzeit Solar cycle, as 2296+-57 years at 12 %var, perhaps its best estimate yet. I use for all analyses the 99% confidence strict Gauss-Vanicek spectral analysis (GVSA) that estimates periods in incomplete records. Based on recent 500-parsec Galactic Center (GC) GeV/TeV Gamma ray surveys by the H.E.S.S. and INTEGRAL telescopes, the GC extremely active central region makes the best candidate host for bursts leaving the discovered signature. A previously reported 3600 years per...

Omerbashich, M

2006-01-01

262

Basic training module for vitreoretinal surgery and the Casey Eye Institute Vitrectomy Indices Tool for Skills Assessment  

PubMed Central

Background The purpose of this study was to design and implement a vitreoretinal training module that would be useful for ophthalmology residents and fellows to learn the basic maneuvers required in vitreoretinal surgery. Methods A prospective pilot study evaluating the training module was undertaken in 13 ophthalmology trainees (residents and vitreoretinal fellows) with varying levels of vitreoretinal training experience. A vitreoretinal training module was designed and consisted of a three-port vitrectomy setup (sclerotomy wound construction, infusion placement), intraocular tasks (core vitrectomy, driving the operating microscope, membrane peel, air–fluid exchange), and wound closure. Standard vitrectomy instrumentation, the VitRet eye (Phillips Studio, Bristol, UK) and vitreous-like fluid using dairy creamer and balanced saline were utilized. A five-point Likert scale, ie, the Casey Eye Institute Vitrectomy Indices Tool for Skills Assessment (CEIVITS), was devised to evaluate each component of the module. Vitreoretinal surgical maneuvers were digitally recorded and graded by an attending vitreoretinal surgeon. Linear regression and correlation were performed to evaluate the relationship between prior vitreoretinal experience and CEIVITS performance. The main outcome measures were correlation of vitreoretinal surgical experience and CEIVITS performance on simulated tasks using a basic vitreoretinal training module. Results Thirteen participants from postgraduate year 2 to postgraduate year 6 levels were evaluated. Nine participants were male and four were female. The median age of participants was 32 (range 30–36) years and surgical experience was 0–410 prior vitreoretinal surgical procedures. A positive correlation (P < 0.05) was observed between vitreoretinal surgical experience and CEIVITS performance on the following tasks: total score (P = 0.021), sclerotomy wound construction (P = 0.047), infusion line placement (P = 0.012), air–fluid exchange (P = 0.004), and wound closure (P = 0.032). Post module surveys showed that the majority of trainees felt that the vitreoretinal training module improved their understanding of vitreoretinal surgery. The nonbiohazardous nature of the setup was advantageous from sanitation and cost perspectives. Conclusion The implementation of our training module for residency and vitreoretinal fellowship was feasible and the CEIVITS adequately assessed basic vitrectomy maneuvers. Given that ophthalmologic and subspecialty instruction migrates from an apprenticeship to a competency-based model, the face and content validity makes the CEIVITS module a promising one in vitreoretinal surgical instruction. PMID:21966195

Yeh, Steven; Chan-Kai, Brian T; Lauer, Andreas K

2011-01-01

263

Geology of the Continental Margin of Enderby and Mac. Robertson Lands, East Antarctica: Insights from a Regional Data Set  

NASA Astrophysics Data System (ADS)

In 2001 and 2002, Australia acquired an integrated geophysical data set over the deep-water continental margin of East Antarctica from west of Enderby Land to offshore from Prydz Bay. The data include approximately 7700 km of high-quality, deep-seismic data with coincident gravity, magnetic and bathymetry data, and 37 non-reversed refraction stations using expendable sonobuoys. Integration of these data with similar quality data recorded by Japan in 1999 allows a new regional interpretation of this sector of the Antarctic margin.

Stagg, H. M. J.; Colwel, J. B.; Direen, N. G.; O'Brien, P. E.; Bernardel, G.; Borissova, I.; Brown, B. J.; Ishirara, T.

2004-09-01

264

Intelligent Virtual Station (IVS)  

NASA Technical Reports Server (NTRS)

The Intelligent Virtual Station (IVS) is enabling the integration of design, training, and operations capabilities into an intelligent virtual station for the International Space Station (ISS). A viewgraph of the IVS Remote Server is presented.

2002-01-01

265

Measurements in polar stratospheric clouds over Antarctica in September 1989  

NASA Technical Reports Server (NTRS)

The results of six balloon flights at McMurdo Station, Antarctica, under varying temperature conditions, are used in a study of polar stratospheric clouds during Sept. 1989. A particle counter, with size resolution in the 0.5 micron radius region, indicates that cloud size distributions are always bimodal. Mode radii ranging from 0.05 to 0.10 microns were observed for the small particle mode, representing the sulfate layer or condensational growth enhancements of it. The data are not inconsistent with the expected increase in size with decreasing temperature of the small particle mode in the sulfate layer owing to deliquescence although this phenomenon is often masked by nitric acid trihydrate (NAT) condensation when temperatures are sufficiently low. Mode radii generally ranged from 1.5 to 3.5 micron for the large particle mode at concentrations 3 to 4 orders of magnitude lower than the small particle mode. The large particle mode, which normally comprises most of the mass, is presumably caused by NAT condensation on larger particles of the sulfate layer and indicates HNO3 mixing ratios of 1 to 5 ppbv for most of the cloud layers observed, suggesting substantial denitrification. On several occasions, distributions were observed with mode radii as high as 7 microns, and correspondingly large inferred mass, indicating water ice clouds in the 12 to 15 km region. On other occasions, absence of such clouds at very low temperatures indicated water vapor mixing ratios of less than 3 ppmv suggesting dehydration. Generally, the inferred HNO3 mixing ratios were higher in the lower stratosphere, suggesting redistribution through particle sedimentation.

Deshler, Terry

1991-01-01

266

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

NASA Astrophysics Data System (ADS)

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

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

1998-06-01

267

Leifsonia psychrotolerans sp. nov., a psychrotolerant species of the family Microbacteriaceae from Livingston Island, Antarctica.  

PubMed

A cold-tolerant, yellow-pigmented, Gram-positive, motile, facultatively anaerobic bacterial strain, LI1(T), was isolated from a moss-covered soil from Livingston Island, Antarctica, near the Bulgarian station St. Kliment Ohridski. Comparative 16S rRNA gene sequence-based phylogenetic analysis placed the strain in a clade with the species Leifsonia kafniensis KFC-22(T), Leifsonia pindariensis PON10(T) and Leifsonia antarctica SPC-20(T), with which it showed sequence similarities of 99.0, 97.9 and 97.9 %, respectively. DNA-DNA hybridization revealed a reassociation value of 2.7 % with L. kafniensis LMG 24362(T). The DNA G+C content of strain LI1(T) was 64.5 mol%. The growth temperature range was -6 to 28 °C, with optimum growth at 16 °C. Growth occurred in 0-5 % NaCl and at pH 4.5-9.5, with optimum growth in 1-2 % NaCl and at pH 5.5-6.5. The predominant fatty acids were anteiso-C(15 : 0), C(18 : 0) and iso-C(15 : 0). The polar lipids were phosphatidylglycerol and diphosphatidylglycerol. Physiological and biochemical tests clearly differentiated strain LI1(T) from L. kafniensis. Therefore, a novel cold-tolerant species within the genus Leifsonia is proposed: Leifsonia psychrotolerans sp. nov. (type strain LI1(T)?= DSM 22824(T)?= NCCB 100313(T)). PMID:20833887

Ganzert, Lars; Bajerski, Felizitas; Mangelsdorf, Kai; Lipski, André; Wagner, Dirk

2011-08-01

268

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

NASA Astrophysics Data System (ADS)

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.

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

2014-12-01

269

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

NASA Astrophysics Data System (ADS)

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

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

2010-11-01

270

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

NASA Astrophysics Data System (ADS)

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.

Smith, Walker O.; Asper, Vernon L.

2001-01-01

271

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...

272

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...

273

Cosmogenic Radionuclides in Chondrite Shower from Otway Massif, Antarctica  

NASA Astrophysics Data System (ADS)

Cosmogenic radionuclides in ordinary chondrites from the first strewnfield identified in Antarctica indicate that the strewnfield was preserved since its fall ~15 kyr ago, while cautioning that not all meteorites in the strewnfield area represent the same fall.

Welten, K. C.; Nishiizumi, K.; Caffee, M. W.; Leclerc, M. D.; Jull, A. J. T.

2009-03-01

274

Concentration of trace inorganic species in surface snow near Dome Fuji, Antarctica  

NASA Astrophysics Data System (ADS)

In the southern hemisphere, especially Antarctica, it is considered that ocean and stratosphere are major source of halogen species. However, there is little data about halogen species contained in snow and ice in Antarctica. In this research, trace inorganic species (Br, Cl, F, I) in the snow samples collected in the Antarctica were analyzed. The snow samples were collected along ca. 1000 km traverse route from Mikaeridai (S16; 69°1'S, 40°3'E, 590 m) to Dome Fuji station (77°19'S, 39°42'E, 3810 m) by the Japan Antarctica research expedition. The samples were transported to Japan without thawing. The quantitative analyses of elements were performed using the ion chromatograph mass spectrometer (IC-MS) and quadrupole type inductively-coupled plasma mass spectrometer (ICP-MS). The IC-MS system consists of a single quadrupole type mass spectrometer (Agilent Technologies 6150) connected to an ionchromatograph (Dionex ICS-2000). IonPac AS11-HC was used as the separation column of the ionchromatograph. 14 anion species (Br-, BrO3-, CH3COO-, CH3SO3-, Cl-, C2O42-, F-, HCOO-, I-, IO3-, NO2-, NO3-, PO43-, SO42-) were analyzed by this system. Average concentration of Cl- was 50 ng/ml. High concentration of Cl- was observed at the coast region compared with the inland region. The concentration was 150 ng/ml at the coast region. On the other hand, the maximum concentration of Br- and I- was observed around 71°S and near 74°S on the traverse route. Average concentration of Br- was 0.2 ng/ml. The maximum concentration of Br- was ca. 0.6 ng/ml. Average concentration of I- was 0.03 ng/ml. The maximum concentration of I- was ca. 0.1 ng/ml. While it is thought that the source of Cl- is mainly ocean, concentration distribution of Br- and I- differs from Cl-. suggesting the contribution of sources other than ocean. Further results and discussion about the behavior and origin of halogen ion species in snow will be presented.

Hirabayashi, M.; Motoyama, H.

2012-12-01

275

First light from the Dome C (Antarctica) of a phase knife stellar coronagraph  

E-print Network

We report on the first daytime on-sky results of a Phase Knife stellar Coronagraph operated in the visible from the French-Italian Concordia station at Dome C of Antarctica. This site has proven in the last few years to offer excellent atmospheric seeing conditions for high spatial resolution observations. The coronagraphic performances obtained from laboratory experiments and numerical models have been compared with those measured from daytime on-sky data recorded on bright single and multiple stars: Canopus (HD 45348), and alpha Centauri (HD 128620J). No correction system was used (adaptive optics or tip-tilt mirror) so that atmospheric turbulence alone defines the image quality, and thus the coronagraphic performances. Moreover, the experiment could not run under optimal operational conditions due to hardware/software problems. Satisfactory results have been obtained: broad band total rejection exceeding 15 were attained in the visible. This first day-time observation campaign yields an experimental feedba...

Guerri, Geraldine; Daban, Jean-Baptiste; Aristidi, Eric; Bendjoya, Philippe; Rivet, Jean-Pierre; Vakili, Farrokh

2009-01-01

276

Time-series analysis of chemical trends in a dated ice core from Antarctica  

SciTech Connect

Polar ice sheets contain valuable information about past atmospheric conditions. Atmospherically produced or transported substances from natural and anthropogenic sources are preserved stratigraphically within the ice layers as a result of both wet and dry deposition mechanisms. Substances deposited include aerosols and gaseous compounds. The analysis of trace elements contained in dated annual snow layers provides a measure of the elemental chemistry content of the atmosphere during the same time interval. The aerosol content of the atmosphere and ice sheets is one of the most important parameters for cloud/radiation interaction processes. Ice cores were obtained from the Byrd Station, West Antarctica, in November, 1989. This study presents results obtained from instrumental neutron activation analysis and ion chromatography on 30 samples over a 20 year period.

Keskin, S.S.; Olmez, I. [Massachusetts Institute of Technology, Cambridge, MA (United States); Langway, C.C. Jr. [State Univ. of New York, Buffalo, NY (United States)

1994-12-31

277

Why Is There One Long Day and One Long Night in Antarctica?  

NSDL National Science Digital Library

This weeklong unit provides an in-depth look at daily and seasonal light changes in Antarctica. Throughout the unit, students collect their findings in a portfolio. Tools for teachers include downloadable readings, daily breakdowns of tasks, strategies for using the activities, a grading sheet, a project rubric sheet, and additional readings. In addition there is an online activity in which students plug in data in order to see daily and seasonal light patterns on a globe or world map, and a hands-on experiment in which students replicate how the Earth simultaneously revolves on its axis and around a light source. In an interview, a safety and health engineer describes what it takes to keep an Antarctic research station running year-round. A student handout with guidance for putting together student portfolios and examples of creative final projects is also provided.

278

Oxygen isotope studies and compilation of isotopic dates from Antarctica  

SciTech Connect

The Quaternary Isotope Laboratory, alone or in collaboration with other investigators, is currently involved in a number of oxygen-isotope studies mainly in Antarctica. Studies of a drill core from the South Pole, seasonal oxygen-18 signals preserved in the Dominion Range, isotope dating of the Ross Ice Shelf, oxygen-18 profiles of the Siple Coast, McMurdo Ice Shelf sampling, and a data compilation of radiometric dates from Antarctica are discussed.

Grootes, P.M.; Stuiver, M.

1986-01-01

279

Birth of a Large Iceberg in Pine Island Bay, Antarctica  

NSDL National Science Digital Library

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.

2004-10-02

280

Antarctica: King of Cold: Grades K-1: Electronic Book  

NSDL National Science Digital Library

This informational text explains that while both the Arctic and Antarctica are cold, Antarctica is much colder and drier - a polar desert. The text is written at a kindergarten through grade one reading level. This is an onscreen version that contains recorded narration allowing students to listen to the text as they read along. Highlighted vocabulary words have individually recorded definitions heard by clicking on the links.

Jessica Fries-Gather

281

Occurrence and diversity of marine yeasts in Antarctica environments  

NASA Astrophysics Data System (ADS)

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

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

2012-03-01

282

Development of long-duration ballooning in Antarctica  

SciTech Connect

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.

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

1990-03-20

283

Scott v. Casey.  

PubMed

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

1983-04-29

284

Ice-Shelf Melting Around Antarctica  

NASA Astrophysics Data System (ADS)

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.

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

2013-07-01

285

Hypersaline “wet patches” in Taylor Valley, Antarctica  

NASA Astrophysics Data System (ADS)

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

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

2012-03-01

286

Mass Casualty Incident Response and Aeromedical Evacuation in Antarctica  

PubMed Central

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

Mills, Christopher N.; Mills, Gregory H.

2011-01-01

287

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

NASA Astrophysics Data System (ADS)

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

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

288

Significant warming of continental West Antarctica in the last 50 years  

NASA Astrophysics Data System (ADS)

We use statistical climate field reconstruction techniques to determine monthly temperature anomalies for the near-surface of the Antarctic ice sheet since 1957. Two independent data sets are used to provide estimates of the spatial covariance patterns of temperature: automatic weather stations and thermal infrared satellite observations. Quality-controlled data from occupied instrumental weather stations are used to determine the amplitude of changes in those covariance patterns through time. We use a modified principal component analyses technique (Steig et al., in review, Nature) to optimize the combination of spatial and temporal information. Verification statistics obtained from subsets of the data demonstrate the resulting reconstructions represent improvements relative to climatological mean values. We find that significant warming has occurred over most of continental West Antarctica. This is an area much larger than previously reported; most studies have concluded that warming is limited to the Antarctic Peninsula. An updated version of the recent temperature reconstruction of Monaghan et al. (2008, JGR) independently confirms our results. Warming in continental West Antarctica in the last 50 years exceeds 0.1 °C/decade, and is strongest in Spring. A possible explanation is an increase in storms in the Amundsen-Bellinghausen sea, resulting in enhanced warm air fluxes to the continent. Increased storminess in this sector is associated with the positive phase of the zonal wave-3 pattern, which independent observations suggest has increased since the 1970s (Raphael, GRL, 2004). The substantial negative sea ice anomalies in the Amundsen-Bellinghausen sea may also play a role. Our results suggest that changes in the wave-3 pattern dominates over (possibly anthropogenic) changes in the Southern Annular Mode in explaining recent Antarctic temperature variability.

Steig, E. J.; Schneider, D. P.

2008-12-01

289

Height changes over subglacial Lake Vostok, East Antarctica: Insights from GNSS observations  

NASA Astrophysics Data System (ADS)

changes of the ice surface above subglacial Lake Vostok, East Antarctica, reflect the integral effect of different processes within the subglacial environment and the ice sheet. Repeated GNSS (Global Navigation Satellite Systems) observations on 56 surface markers in the Lake Vostok region spanning 11 years and continuous GNSS observations at Vostok station over 5 years are used to determine the vertical firn particle movement. Vertical marker velocities are derived with an accuracy of 1 cm/yr or better. Repeated measurements of surface height profiles around Vostok station using kinematic GNSS observations on a snowmobile allow the quantification of surface height changes at 308 crossover points. The height change rate was determined at 1 ± 5 mm/yr, thus indicating a stable ice surface height over the last decade. It is concluded that both the local mass balance of the ice and the lake level of the entire lake have been stable throughout the observation period. The continuous GNSS observations demonstrate that the particle heights vary linearly with time. Nonlinear height changes do not exceed ±1 cm at Vostok station and constrain the magnitude of spatiotemporal lake-level variations. ICESat laser altimetry data confirm that the amplitude of the surface deformations over the lake is restricted to a few centimeters. Assuming the ice sheet to be in steady state over the entire lake, estimates for the surface accumulation, on basal accretion/melt rates and on flux divergence, are derived.

Richter, Andreas; Popov, Sergey V.; Fritsche, Mathias; Lukin, Valery V.; Matveev, Alexey Yu.; Ekaykin, Alexey A.; Lipenkov, Vladimir Ya.; Fedorov, Denis V.; Eberlein, Lutz; Schröder, Ludwig; Ewert, Heiko; Horwath, Martin; Dietrich, Reinhard

2014-11-01

290

Space Station Spartan study  

NASA Technical Reports Server (NTRS)

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.

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

1985-01-01

291

Antarctic Ice Sheet: Stable Isotope Analyses of Byrd Station Cores and Interhemispheric Climatic Implications  

Microsoft Academic Search

Oxygen- and hydrogen-isotope analyses from the core hole through the Antarctic Ice Sheet at Byrd Station define temperature variations over more than 75,000 years. Synchronism between major climatic changes in Antarctica and the Northern Hemisphere is strongly indicated. The Wisconsin cold interval extended from 75,000 to 11,000 years ago. Three intra-Wisconsin warmer phases were all colder than pre- or post-Wisconsin

Samuel Epstein; R. P. Sharp; A. J. Gow

1970-01-01

292

Applicability of NASA Polar Technologies to British Antarctic Survey Halley VI Research Station  

NASA Technical Reports Server (NTRS)

From 1993 through 1997 NASA and the National Science Foundation (NSF), developed a variety of environmental infrastructure technologies for use at the Amundsen-Scott South Pole Station. The objective of this program was to reduce the cost of operating the South Pole Station, reduce the environmental impact of the Station, and to increase the quality of life for Station inhabitants. The result of this program was the development of a set of sustainability technologies designed specifically for Polar applications. In the intervening eight years many of the technologies developed through this program have been commercialized and tested in extreme environments and are now available for use throughout Antarctica and circumpolar north. The objective of this document is to provide information covering technologies that might also be applicable to the British Antarctic Survey s (BAS) proposed new Halley VI Research Station. All technologies described are commercially available.

Flynn, Michael

2005-01-01

293

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

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

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

2011-01-01

294

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

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

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

2011-01-01

295

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

E-print Network

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 changes over the Amundsen Sea, ...

Criscitiello, Alison S.

296

Space Station Power System  

NASA Technical Reports Server (NTRS)

The strategies, reasoning, and planning guidelines used in the development of the United States Space Station Program are outlined. The power required to support Space Station missions and housekeeping loads is a key driver in overall Space Station design. conversely, Space Station requirements drive the power technology. Various power system technology options are discussed. The mission analysis studies resulting in the required Space Station capabilities are also discussed. An example of Space Station functions and a concept to provide them is presented. The weight, area, payload and altitude requirements on draft and mass requirements are described with a summary and status of key power systems technology requirements and issues.

Baraona, C. R.

1984-01-01

297

Controlling mechanisms of Thwaites Glacier, West Antarctica  

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

298

Hydrogen emissions from Erebus volcano, Antarctica  

NASA Astrophysics Data System (ADS)

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

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

2012-11-01

299

Odd cloud in the Ross Sea, Antarctica  

NASA Technical Reports Server (NTRS)

On January 28, 2002, MODIS captured this image of an interesting cloud formation in the boundary waters between Antarctica's Ross Sea and the Southern Ocean. A dragon? A snake? A fish? No, but it is an interesting example of the atmospheric physics of convection. The 'eye' of this dragon-looking cloud is likely a small spot of convection, the process by which hot moist air rises up into the atmosphere, often producing big, fluffy clouds as moisture in the air condenses as rises into the colder parts of the atmosphere. A false color analysis that shows different kinds of clouds in different colors reveals that the eye is composed of ice crystals while the 'body' is a liquid water cloud. This suggests that the eye is higher up in the atmosphere than the body. The most likely explanation for the eye feature is that the warm, rising air mass had enough buoyancy to punch through the liquid water cloud. As a convective parcel of air rises into the atmosphere, it pushes the colder air that is higher up out of its way. That cold air spills down over the sides of the convective air mass, and in this case has cleared away part of the liquid cloud layer below in the process. This spilling over of cold air from higher up in the atmosphere is the reason why thunderstorms are often accompanied by a cool breeze. Credit: Jacques Descloitres, MODIS Land Rapid Response Team, NASA/GSFC

2002-01-01

300

Strawberries at Troupe Station.  

E-print Network

, TEXAS. Reports and Bulletins are sent free upon application to the Director. STRAWBERRIES AT TROUPE STATION. var the the BY EDWARD C. GREEN ASSISTANT HORTICULTURIST The establishment of Troupe Station, Smith County, has increase( greatly...

Green, Edward C.

1904-01-01

301

Tectonic evolution of west Antarctica and its relation to east Antarctica  

SciTech Connect

West Antarctica consists of five major blocks of continental crust separated by deep sub-ice basins. Marie Byrd Land appears to have been rifted off the adjacent margin of the East Antarctic craton along the line of the Transantarctic Mountains during the Mesozoic. Ellsworth-Whitmore mountains and Haag Nunataks blocks were also rifted from the margin of the craton. They appear to have moved together with the Antarctic Peninsula and Thurston Island blocks, segments of a Pacific margin Mesozoic-Cenozoic magmatic arc, during the Mesozoic opening of the Weddell Sea basin. Paleomagnetic data suggest that all four of these blocks remained attached to western Gondwanaland (South America-Africa) until approximately 125 m.y. ago, and that the present geographic configuration of the Antarctic continent was essentially complete by the mid-Cretaceous, although important Cenozoic rifting has also occurred. Fragmentation of the Gondwanaland supercontinent was preceded in the Middle to Late Jurassic by an important and widespread thermal event of uncertain origin that resulted in the emplacement of an extensive bimodal igneous suite in South America, Africa, Antarctica, and Australia. This was associated with the development of the composite back-arc basin along the western margin of South America. Inversion of this basin in the mid-Cretaceous initiated Andean orogenesis. The presentation will include new data from the joint US-UK West Antarctic Tectonics Project.

Dalziel, I.W.D.

1987-05-01

302

The International Space Station  

NSDL National Science Digital Library

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

303

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

PubMed

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

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

304

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.

305

The SCAR Astronomy & Astrophysics from Antarctica Scientific Research Programme  

NASA Astrophysics Data System (ADS)

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

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

2013-01-01

306

Cryoconite and Ice-bubble Microbial Ecosystems in Antarctica  

NASA Technical Reports Server (NTRS)

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.

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

2000-01-01

307

Alternative regimes for mineral-resource development in Antarctica  

SciTech Connect

Alternative regimes for Antarctica are evaluated within which nonliving resources of the continent and adjacent offshore areas can be developed and managed. The study estimates: (a) the better options for each of the states active in Antarctica, and (b) the minerals regime which would best serve the interest of the Antarctic Treaty Consultative States. Multi-Attribute Utility Analysis was used to evaluate alternative regimes, including: (1) identification of relevant interests of states in Antarctica, (2) estimation of the relative importance of these interests for all relevant actors, (3) definition of alternative minerals regimes, and (4) evaluation of the probable effect of each alternative on satisfaction of the interests of each state. The data were used to calculate each state's utilities for the twelve options considered. A questionnaire was sent to Antarctic experts in all Consultative countries.

Westermeyer, W.E.

1982-01-01

308

Permafrost and periglacial research in Antarctica: New results and perspectives  

NASA Astrophysics Data System (ADS)

In the last two years the research within the Antarctic Permafrost, Periglacial Environments and Soils (ANTPAS) Expert Group of the Scientific Committee on Antarctic Research (SCAR) and Working Group of the International Permafrost Association (IPA) provided new results on the dynamics of periglacial environments both in Maritime and Continental Antarctica. In continental Antarctica despite the absence of air warming, in the last 15 years an active layer thickening and acceleration of permafrost degradation erosional phenomena were reported, these being mainly related to the increase of solar radiation. On the other hand, in Maritime Antarctica, with a dramatic air warming, permafrost degradation has been observed, but the role of snow cover on the ground energy balance and consequently on permafrost and active layer has been underlined. Moreover, many contributions on the knowledge on the characteristics of the Antarctic soils were carried out in several areas along a wide latitudinal range.

Guglielmin, Mauro; Vieira, Gonçalo

2014-11-01

309

Ecological Biogeography of the Terrestrial Nematodes of Victoria Land, Antarctica  

PubMed Central

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

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

2014-01-01

310

Ice plug prevents irreversible discharge from East Antarctica  

NASA Astrophysics Data System (ADS)

Changes in ice discharge from Antarctica constitute the largest uncertainty in future sea-level projections, mainly because of the unknown response of its marine basins. Most of West Antarctica's marine ice sheet lies on an inland-sloping bed and is thereby prone to a marine ice sheet instability. A similar topographic configuration is found in large parts of East Antarctica, which holds marine ice equivalent to 19 m of global sea-level rise, that is, more than five times that of West Antarctica. Within East Antarctica, the Wilkes Basin holds the largest volume of marine ice that is fully connected by subglacial troughs. This ice body was significantly reduced during the Pliocene epoch. Strong melting underneath adjacent ice shelves with similar bathymetry indicates the ice sheet's sensitivity to climatic perturbations. The stability of the Wilkes marine ice sheet has not been the subject of any comprehensive assessment of future sea level. Using recently improved topographic data in combination with ice-dynamic simulations, we show here that the removal of a specific coastal ice volume equivalent to less than 80 mm of global sea-level rise at the margin of the Wilkes Basin destabilizes the regional ice flow and leads to a self-sustained discharge of the entire basin and a global sea-level rise of 3-4 m. Our results are robust with respect to variation in ice parameters, forcing details and model resolution as well as increased surface mass balance, indicating that East Antarctica may become a large contributor to future sea-level rise on timescales beyond a century.

Mengel, M.; Levermann, A.

2014-06-01

311

The first record of a sauropod dinosaur from Antarctica  

NASA Astrophysics Data System (ADS)

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

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

2012-01-01

312

The GRAD high-altitude balloon flight over Antarctica  

NASA Technical Reports Server (NTRS)

The Gamma Ray Advanced Detector (GRAD) consists of a n-type germanium detector inside an active bismuth-germanate Compton and charged particle shield with additional active plastic shielding across the aperture. It will be flown on a high-altitude balloon at 36 km altitude at a latitude of 78 deg S over Antarctica for observations of gamma radiation emitted by the radioactive decay of Co-56 in the supernova SN1987A, for assessment of the performance of bismuth-germanate scintillation material in the radiation environment of near space, for gathering information on the gamma-ray background over Antarctica, and for testing fault-tolerant software.

Eichhorn, G.; Coldwell, R. L.; Dunnam, F. E.; Rester, A. C.; Trombka, J. I.; Starr, R.

1989-01-01

313

Climate change during the last deglaciation in Antarctica  

SciTech Connect

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

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

1996-06-14

314

Declassified Intelligence Satellite Photography (DISP) Coverage of Antarctica  

NASA Technical Reports Server (NTRS)

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.

Bindschadler, Robert; Seider, Wendy

1998-01-01

315

Low-power magnetometer observation with satellite data transmission at unmanned site in Antarctica  

NASA Astrophysics Data System (ADS)

We will report technical experiences from 6 years of unmanned low power magnetometer observation in Antarctica with daily data transmission via Iridium satellite telephone link. One of the difficulties of unmanned observation in Antarctica is dark winter months in which power supply from solar panel can not be expected. One solution for this difficulty is to minimize the power consumption (as small as ~1 W) to manage the observation in winter months with limited amount of batteries (~400Ah). Another difficulty is to collect data from the observation site. It is quite expensive and laborious to send a party to the observation site to obtain the data in Antarctica. Although cost for satellite communication is expensive, it is much more economical to collect data via satellite data link by installing a telephone terminal into the observation system. It seems that power consumption of a satellite phone (~10 W) does not fit to the low power system. However, as long as the observed data is not too large (<1 Mbyte per day), turn on period of the satellite phone is short (<1 hour per day) and the daily average of total power consumption lies within the available power of ~1 W. We have developed low-power magnetometer system with Iridium satellite phone data link. Basic design of the low-power system is similar to that developed by British Antarctic Survey (intermittent operation of magnetometer and GPS). However, we have made some improvements; reduced power consumption (0.2 W) at high sampling rate (1Hz) and increased sensitivity (0.2nT), so that geomagnetic pulsation study can be possible. In our observation system, satellite data transfer is only made in sunlit season with the total power consumption of 1 W (0.8W for Iridium phone and 0.2W for others). During dark winter months, observed data are stored in CF memory with diminished power consumption of 0.2W. When the sun comes in spring, the stored data are transmitted along with the daily observed data. It takes nearly two months to complete the transmission of data stored in winter months. We have installed two sets of low-power magnetometer at inland and coastal area in January, 2007. We added one set every austral summer and, by January 2010, 5 magnetometers are deployed within a radius of 700km from Syowa Station. The observed data can be used for the study of magnetic pulsations, as well as small and medium scale structure of ionospheric currents at the time of auroral substorm.

Yamagishi, H.; Kadokura, A.

2012-12-01

316

Ice megadunes on Mars: analogy with Antarctica  

NASA Astrophysics Data System (ADS)

Mass and energy balance of ice sheets are driven by complex interactions between the atmosphere and the cryosphere. Feedbacks between katabatic winds and the cryosphere may lead to the formation of sedimentation waves, so-called megadunes, at the surface of ice sheets. These have been first described in Antarctica. Here we use topographic data, optical images, and spectroscopic data acquired by Mars orbiters. We show that the surface of the Martian North Polar Cap displays two superimposed sets of sedimentation waves with differing wavelengths. These sedimentation waves have similarities with Antarctic ice megadunes regarding their surface morphology, texture, grain size, and internal stratigraphic architecture. Their shallow-dipping upwind sides, their tops and the intervening troughs are covered by young ice and occasional sastrugi fields, indicative of net accumulation. On the other hand, their steep-dipping downwind sides either expose exhumed layers of dusty old ice or correspond to smooth surfaces of coarse-grained ice, indicative of net ablation or reduced net accumulation associated with sublimation and metamorphism. These surface characteristics and the internal stratigraphic architecture revealed by radar sounding are consistent with the interpretation that both sets of Martian sedimentation waves grow and migrate upwind in response to the development of periodic accumulation/ablation patterns controlled by katabatic winds. The smaller waves, characterized by reduced net accumulation on their downwind sides, are probably analogous to the Antarctic megadunes that have been described so far. On the other hand, a terrestrial equivalent remains to be discovered for the larger ones, characterized by net ablation on their downwind sides. The recognition of these sedimentation waves provides the basis for the development of a common model of ice/wind interaction at the surface of Martian and terrestrial ice sheets and for future investigations on the respective roles of wind-driven particle transport, heat and mass transfer of water vapor, ice metamorphism and glacial flow of ice sheets.

Herny, Clémence; Massé, Marion; Bourgeois, Olivier; Carpy, Sabrina; Le Mouélic, Stéphane; Appéré, Thomas; Smith, Isaac; Spiga, Aymeric; Rodriguez, Sébastien

2014-05-01

317

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

SciTech Connect

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.

Crockett, A.B.

1994-04-01

318

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

Microsoft Academic Search

The Earth's magnetosphere is host to remarkable very low frequency (VLF) electromagnetic signals of natural origin. One of these, called a whistler, originates in lightning. Others, such as hiss and chorus, originate within the plasma itself. They are important for at least three reasons. First, they reveal the properties of the plasma through which they travel and thus can be

R. A. Helliwell

1988-01-01

319

Seasonal and inter-annual mass variability in Antarctica from GRACE  

NASA Astrophysics Data System (ADS)

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.

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

2011-12-01

320

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

NASA Astrophysics Data System (ADS)

A meta-analysis of photosynthesis/irradiance measurements was completed using data from the Ross Sea, Antarctica. A total of 544 independent measurements were included. PsB, the maximum, chlorophyll-specific, irradiance-saturated rate of photosynthesis, averaged 1.07 ± 0.060 ?g C (?g chl)-1 h-1. Light-limited photosynthetic rates (?) averaged 0.03 ± 0.023 ?g C (?g chl)-1 h-1 ?mol photons m-2 s-1)-1. Significant variations in PsB and ? were found as a function of season, with spring maximum photosynthetic rates being 59% greater than those in summer. Similarly, ? values were 48% greater in spring. There was no detectable effect of space on the photosynthetic parameters, and temperature and macronutrient (NO3) concentrations also did not exert a strong influence. However, irradiance, dissolved iron concentrations, and carbon dioxide concentrations when altered under controlled conditions exerted significant influences on photosynthetic parameters. Specifically, reduced irradiance resulted in decreased PsB and ? values, whereas reduced iron concentrations were associated with increased PsB and ? values. Increased CO2 concentrations also resulted in significantly increased PsB and ? values. No significant difference was detected between stations dominated by diatoms and those dominated by the haptophyte Phaeocystis antarctica. The meta-analysis generally 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 the productivity of polar systems a more detailed model that includes temporal effects of photosynthetic parameters will be required.

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

2014-12-01

321

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

PubMed

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

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

2015-02-01

322

Space Radar Image of Weddell Sea, Antarctica  

NASA Technical Reports Server (NTRS)

This Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar color composite shows a portion of the Weddell Sea, which is adjacent to the continent of Antarctica. The image shows extensive coverage of first-year sea ice mixtures and patches of open water inside the ice margin. The image covers a 100 kilometer by 30 kilometer (62 mile by 18.5 mile) region of the southern ocean, centered at approximately 57 degrees south latitude and 3 degrees east longitude, which was acquired on October 3, 1994. Data used to create this image were obtained using the L-band (horizontally transmitted and vertically received) in red; the L-band (horizontally transmitted and received) in green; and the C-band (horizontally transmitted and received) in blue. The sea ice, which appears rust-brown in the image, is composed of loosely packed floes from approximately 1 meter to 2 meters (3 feet to 6.5 feet) thick and ranging from 1 meter to 20 meters (3 feet to 65.5 feet) in diameter. Large patches of open water, shown as turquoise blue, are scattered throughout the area, which is typical for ice margins experiencing off-ice winds. The thin, well-organized lines clearly visible in the ice pack are caused by radar energy reflected by floes riding the crest of ocean swells. The wispy, black features seen throughout the image represent areas where new ice is forming. Sea ice, because it acts as an insulator, reduces the loss of heat between the relatively warm ocean and cold atmosphere. This interaction is an important component of the global climate system. Because of the unique combination of winds, currents and temperatures found in this region, ice can extend many hundreds of kilometers north of Antarctica each winter, which classifies the Weddell Sea as one of nature's greatest ice-making engines. During the formation of sea ice, great quantities of salt are expelled from the frozen water. The salt increases the density of the upper layer of sea water, which then sinks to great depths. Oceanographers believe this process forms most of the oceans' deep water. Sea ice covering all of the southern oceans, including the Weddell Sea, typically reaches its most northerly extent in about September. As periods of daylight become gradually longer in the Southern Hemisphere, ice formation stops and the ice edge retreats southward. By February, most of the sea ice surrounding Antarctica disappears. Imaging radar is extremely useful for studying the polar regions because of the long periods of darkness and extensive cloud cover. The multiple frequencies of the SIR-C/X-SAR instruments allow further study into ways of improving the separation of the various thickness ranges of sea ice, which are vital to understanding the heat balance in the ice, ocean and atmospheric system. Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar (SIR-C/X-SAR) is part of NASA's Mission to Planet Earth. The radars illuminate Earth with microwaves, allowing detailed observations at any time, regardless of weather or sunlight conditions. SIR-C/X-SAR uses three microwave wavelengths: L-band (24 cm), C-band (6 cm) and X-band (3 cm). The multi-frequency data will be used by the international scientific community to better understand the global environment and how it is changing. The SIR-C/X-SAR data, complemented by aircraft and ground studies, will give scientists clearer insights into those environmental changes which are caused by nature and those changes which are induced by human activity. SIR-C was developed by NASA's Jet Propulsion Laboratory. X-SAR was developed by the Dornier and Alenia Spazio companies for the German space agency, Deutsche Agentur fuer Raumfahrtangelegenheiten (DARA), and the Italian space agency, Agenzia Spaziale Italiana (ASI), with the Deutsche Forschungsanstalt fuer Luft und Raumfahrt e.V.(DLR), the major partner in science, operations and data processing of X-SAR.

1994-01-01

323

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

Microsoft Academic Search

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

P. D. Crittenden

1998-01-01

324

Variations of snow petrel breeding success in relation to sea-ice extent: detecting local response to large-scale processes?  

Microsoft Academic Search

Demographic parameters were estimated for snow petrels Pagodroma nivea nesting at the study colony of Reeve Hill near Casey station, Antarctica between 1984 and 2003. Average breeding success for the colony varied from 18.2% to 76.5%. Breeding effort, hatching and fledging success were subject to a high interannual variability. We examined the influence of regional sea-ice extent on the breeding

Frederique Olivier; Jan A. van Franeker; Jeroen C. S. Creuwels; Eric J. Woehler

2005-01-01

325

Space Station Freedom Utilization Conference  

NASA Technical Reports Server (NTRS)

The topics addressed in Space Station Freedom Utilization Conference are: (1) space station freedom overview and research capabilities; (2) space station freedom research plans and opportunities; (3) life sciences research on space station freedom; (4) technology research on space station freedom; (5) microgravity research and biotechnology on space station freedom; and (6) closing plenary.

1992-01-01

326

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

NASA Astrophysics Data System (ADS)

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.

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

2014-10-01

327

A Taxodiaceous Seed Cone from the Triassic of Antarctica  

Microsoft Academic Search

A silicified seed cone is described from the lower Middle Triassic of Antarctica. The cone measures up to 3.4 cm long and 1.4 cm wide, and consists of helically arranged cone scales attached to a eustelic axis. Bract and ovuliferous scale are approximately of equal length and fused at the base. The bract is entire and vascularized by a single

Xuanli Yao; Thomas N. Taylor; Edith L. Taylor

1997-01-01

328

HUMAN IMPACT ON TERRESTRIAL ECOSYSTEMS IN WEST ANTARCTICA  

Microsoft Academic Search

Examples of synanthropization of flora in the South Shetland Islands (West Antarctica) are presented. Investigations on man's impact were carried out between 1986 and 1993. Human impact on plant cover takes place in two parallel processes: some species (plantae hemerophobae) decrease their geographical range, as a result of direct and indirect habitat destruction; while others extend their area of occurrence

Maria OLECH

329

Vascular plants as bioindicators of regional warming in Antarctica  

Microsoft Academic Search

Monitoring selected populations of the only two native Antarctic vascular plant species (Colobanthus quitensis andDeschampsia antarctica) over a 27-year period has revealed a significant and relatively rapid increase in numbers of individuals and populations at two widely separated localities in the maritime Antarctic. There is strong evidence that this increase is a response to a warming trend in summer air

R. I. Lewis Smith

1994-01-01

330

Antarctica: Arena for South American Cooperation or Conflict.  

ERIC Educational Resources Information Center

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

Child, Jack

331

Accelerated Sea-Level Rise from West Antarctica  

Microsoft Academic Search

Recent aircraft and satellite laser altimeter surveys of the Amundsen Sea sector of West Antarctica show that local glaciers are discharging about 250 cubic kilometers of ice per year to the ocean, almost 60% more than is accumulated within their catchment basins. This discharge is sufficient to raise sea level by more than 0.2 millimeters per year. Glacier thinning rates

R. Thomas; E. Rignot; G. Casassa; P. Kanagaratnam; C. Acuña; T. Akins; H. Brecher; E. Frederick; P. Gogineni; W. Krabill; S. Manizade; H. Ramamoorthy; A. Rivera; R. Russell; J. Sonntag; R. Swift; J. Yungel; J. Zwally

2004-01-01

332

New Aerogeophysical exploration of the Gamburtsev Province (East Antarctica)  

Microsoft Academic Search

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

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

2009-01-01

333

Southern Hemisphere Springtails: Could Any Have Survived Glaciation of Antarctica?  

Microsoft Academic Search

Abstract Throughout the Southern Hemisphere many terrestrial taxa have circum-Antarctic distributions. This pattern is generally attributed to ongoing dispersal (by wind, water, or migrating birds), or relict Gondwanan distributions. Few of these terrestrial taxa have extant representatives in Antarctica, but such taxa would contribute to our understanding of the evolutionary origins of the continental Antarctic fauna. Either these taxa have

Mark I. Stevens; Penelope Greenslade; Ian D. Hogg; Paul Sunnucks

2006-01-01

334

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

NASA Technical Reports Server (NTRS)

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

Hale, M. E.; Friedmann, E. I. (Principal Investigator)

1987-01-01

335

Observational Study of the Atmospheric Boundary Layer over Antarctica  

Microsoft Academic Search

During the austral summer of 1982\\/83, measurements of wind and temperature profiles were made through the atmospheric boundary layer in Adelie Land, East Antarctica, an area known for strong katabatic winds. It was found that a shallow but strong temperature inversion was developed at night, and destroyed during the day, resulting in the development of a well-mixed layer. Wind hodographs

Zbigniew Sorbjan; Yuji Kodama; Gerd Wendler

1986-01-01

336

CREAM: 70 days of flight from 2 launches in Antarctica  

Microsoft Academic Search

The Cosmic-Ray Energetics And Mass balloon-borne experiment has been launched twice in Antarctica, first in December 2004 and again in December 2005. It circumnavigated the South Pole three times during the first flight, which set a flight duration record of 42 days. A cumulative duration of 70 days within 13 months was achieved when the second flight completed 28 days

E. S. Seo; H. S. Ahn; P. Allison; M. G. Bagliesi; L. Barbier; A. Barrau; R. Bazer-Bachi; J. J. Beatty; G. Bigongiari; P. Boyle; T. J. Brandt; M. Buénerd; J. T. Childers; N. B. Conklin; S. Coutu; L. Derome; M. A. DuVernois; O. Ganel; J. H. Han; J. A. Jeon; K. C. Kim; M. H. Lee; L. Lutz; A. Malinin; M. Mangin-Brinet; P. S. Marrocchesi; P. Maestro; A. Menchaca-Rocha; S. Minnick; S. I. Mognet; S. Nam; S. Nutter; I. H. Park; N. H. Park; A. Putze; R. Sina; S. Swordy; S. Wakely; P. Walpole; J. Wu; J. Yang; Y. S. Yoon; R. Zei; S. Y. Zinn

2008-01-01

337

Airborne geophysical study in the pensacola mountains of antarctica  

USGS Publications Warehouse

A seismic reflection, gravity, and aeromagnetic reconnaissance was made in the Pensacola Mountains, Antarctica, during the 1965-66 austral summer. Prominent ice streams located between the Neptune and Patuxent Ranges and east of the Forrestal Range overlie channels in the rock surface 2000 meters below sea level which are probably of glacial origin. Seismic reflections show that the Filchner Ice Shelf is 1270 meters thick near its southern margin. Along the boundary between West and East Antarctica, Bouguer anomalies decrease from +60 milligals in West Antarctica to -80 milligals in East Antarctica. An abrupt change in crustal structure across this boundary is required to explain the 2 milligals per kilometer gradient. This may indicate a fault extending through the crust into the mantle. Aeromagnetic profiles delineate anomalies up to 1800 ?? associated with the basic stratiform intrusion which comprises the Dufek and Forrestal ranges. A probable minimum area of 9500 square kilometers is calculated for the intrusive body on the basis of the magnetic anomalies, making it one of the largest bodies of its type. The extension of this magnetic anomaly across a fault forming the north border of the Pensacola Mountains probably precludes transcurrent movement.

Behrendt, John C.; Meister, L.; Henderson, J.R.

1966-01-01

338

Average September Ozone Levels over Antarctica for 1979 to 1998  

NSDL National Science Digital Library

The evolution of the ozone hole over Antarctica as shown through measurements of average ozone for September for the years 1979 through 1998, excluding 1995. These measurements were made by the TOMS instruments on Nimbus-7, Meteor-3 and Earth Probe. Dark blue represent regions of low ozone and red represents regions of high ozone.

Greg Shirah

1998-10-02

339

GLACIAL GEOLOGY OF CAPE BIRD, ROSS ISLAND, ANTARCTICA  

E-print Network

GLACIAL GEOLOGY OF CAPE BIRD, ROSS ISLAND, ANTARCTICA BY TINA M. DOCHAT1, DAVID R. MARCHANT2, University of Maine, Orono, Maine, USA Dochat,TinaM.,Marchant,D.R.andDenton,G.H.,2000:Gla- cialgeologyof CapeBird,shells,andforaminifersindicatethatacomponent of theicewithinthissheetflowedthroughtheTAM,groundedon theRoss Seafloor,andultimatelyadvancedlandwardontothe lowerslopes of MountBird

Marchant, David R.

340

A Raman scattering and FT-IR spectroscopic study on the effect of the solar radiation in Antarctica on bovine cornea  

NASA Astrophysics Data System (ADS)

The Raman scattering and FT-IR spectra of the corneas, transported to the Syowa station in Antarctica and exposed to the solar radiation of the mid-summer for four weeks, were studied to reveal that type IV collagen involved in corneas were fragmented. The amide I and III Raman bands were observed at 1660 and 1245 cm -1, respectively, and the amide I and II infrared bands were observed at 1655 and 1545 cm -1, respectively, for original corneas before exposure. The background of Raman signals prominently increased and the ratio of amide II infrared band versus amide I decreased by the solar radiation in Antarctica. The control experiment using an artificial UV lamp was also performed in laboratory. The decline rate of the amide II/amide I was utilized for estimating the degree of fragmentation of collagen, to reveal that the addition of vitamin C suppressed the reaction while the addition of sugars promoted it. The effect of the solar radiation in Antarctica on the corneas was estimated as the same as the artificial UV lamp of four weeks (Raman) or one week (FT-IR) exposure.

Yamamoto, Tatsuyuki; Murakami, Naoki; Yoshikiyo, Keisuke; Takahashi, Tetsuya; Yamamoto, Naoyuki

2010-01-01

341

Seasonal and diurnal dependence of Pc 3-5 magnetic pulsation power at geomagnetically conjugate stations in the auroral zones  

SciTech Connect

Seasonal and diurnal variations of Pc 3-5 magnetic pulsation powers have been examined using 2 years of magnetic data from geomagnetically conjugate stations, Syowa in Antarctica and Husafell and Tjoernes in Iceland. The magnetic pulsation powers are found to be relatively higher at the winter hemisphere station than at the summer station. The pulsations observed during equinox show a diurnal dependence, i.e., that the power density is higher in the geomagnetic morning at the stations in Iceland than at Syowa, and this relationship is reversed in the afternoon. The power density ratio of Pc 3 pulsations between the conjugate stations, which is associated with the seasons and with local time, is higher than that of Pc 5. These characteristics can be attributed to the effects of sunlight in the ionosphere, i.e., Pc 3-5 pulsations are shielded when the waves propagate from the magnetosphere to the ground through the sunlit ionosphere.

Saito, Hiroaki (Univ. of Electro-Communications, Tokyo (Japan) National Institute of Polar Research, Tokyo (Japan)); Sato, Natsuo (National Institute of Polar Research, Tokyo (Japan)); Tonegawa, Yutaka (Tokai Univ., Hiratsuka (Japan)); Yoshino, Takeo (Univ. of Electro-Communications, Tokyo (Japan)); Saemundsson, T. (Univ. of Iceland, Reykjavik (Iceland))

1989-06-01

342

Microbial Energetics Beneath the Taylor Glacier, Antarctica  

NASA Astrophysics Data System (ADS)

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

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

2007-12-01

343

Weather Station Model  

NSDL National Science Digital Library

This lesson instructs students on how to read station models, the symbols used on weather maps to show data (temperature, wind speed and direction, barometeric pressure, etc.) for a given reporting station. It includes a diagram of a station model, an explanation of the data conveyed by the numbers and symbols, and a table of definitions for the graphic symbols used with models. There is also a set of interactive station models students can use for practice at interpretation, and an interactive exercise in which students use real-time weather data to interpret models.

344

International Space Station: Update  

NSDL National Science Digital Library

In November 1998, Zarya was launched into space, ushering in the era of the International Space Station (featured in the November 25, 1998 Scout Report for Science & Engineering). This month, the docking of the Zvezda Service Module marks the beginning of yet another phase -- in which Zvezda will serve as living quarters to the first ever resident crew (Expedition One), scheduled to arrive at the International Space Station in early November. This site from NASA provides updated information on the International Space Station, including recent news, planned missions, and a virtual tour of the (yet-to-be-completed) station.

345

Baseline values for metals in soils on Fildes Peninsula, King George Island, Antarctica: the extent of anthropogenic pollution.  

PubMed

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

Lu, Zhibo; Cai, Minghong; Wang, Juan; Yang, Haizhen; He, Jianfeng

2012-11-01

346

Changes in the character of Polar stratospheric clouds over Antarctica in 1992 due to the Pinatubo volcanic aerosol  

SciTech Connect

Vertical profiles of aerosol concentration were measured on 8 occasions from McMurdo Station, Antarctica (78[degrees]S), between late August and early October 1992. Polar stratospheric clouds (PSCs) were observed on 6 of these soundings. The characteristics of PSCs, and ozone, were quite different above and below about 16 km. Above 16 km PSCs were variable in time, with particles > 1.0 [mu]m radius contributing significantly to the surface area, generally < 8 [mu]m[sup 2] cm[sup [minus]3]. Below 16 km PSCs were much more stable and were dominated by high concentrations of smaller particles, < 1.0 [mu]m, with surface areas of 20-30 [mu]m[sup 2] cm[sup [minus]3]. This lower layer coincided with the altitude of the primary Pinatubo volcanic aerosol as measured in mid September and October, and with the 4 km region of the atmosphere where ozone was virtually completed destroyed over Antarctica in 1992. 12 refs., 4 figs.

Deshler, T.; Johnson, B.J.; Rozier, W.R. (Univ. of Wyoming, Laramie, WY (United States))

1994-02-15

347

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

NASA Astrophysics Data System (ADS)

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

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

2013-01-01

348

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

NASA Astrophysics Data System (ADS)

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).

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

2013-05-01

349

"Inventive" Learning Stations  

ERIC Educational Resources Information Center

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

Jarrett, Olga

2010-01-01

350

Sol Station: Sol  

NSDL National Science Digital Library

This site from Sol Station contains much information on the Sun, its history, and its future. Special emphasis is placed on how the Sun produces an environment on Earth that is suitable for life. The site is illustrated with many images, charts, and several videos. Also provided are links to Sol Station sites on the planets and nearby stars.

2006-11-25

351

Weather Stations: Storms  

NSDL National Science Digital Library

In this activity, learners test how cornstarch and glitter in water move when disturbed. Learners compare their observations with videos of Jupiter's and Earth's storm movements. This activity is one station that can be combined with other stations for an hour and half lesson on weather patterns on Jupiter and Earth.

Institute, Lunar A.; Nasa

2011-01-01

352

Space station executive summary  

NASA Technical Reports Server (NTRS)

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.

1972-01-01

353

Future Weather Station  

NSDL National Science Digital Library

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

354

Station 13 revisited  

NASA Astrophysics Data System (ADS)

The article I wrote on the somewhat mysterious tracking station at Babsfontein in Gauteng (MNASSA Vol. 11 nos 3&4, April 2012) resulted in some correspondence, enabling me to get into contact with people who had worked at the station. This made it necessary to update the original article.

Roberts, G.

2012-10-01

355

The Space Station  

Microsoft Academic Search

The configuration of the Space Station under design studies by NASA is limited only by the capabilities of the Shuttle and the purposes to which it is applied. Once the standard interlocks, launch vibration modes, and pallet designs are fixed, all other assembly of modular components, testing, and trim will be performed in space. The Station will serve for long-term

R. Sharples; J. Hieatt

1984-01-01

356

The Space Station era  

Microsoft Academic Search

The users, configuration, and uses of the manned Space Station planned by the U.S. are outlined. The station is to be operational by 1994 and will serve scientific and commercial purposes. It is noted that the exploration of space, like the exploration of any other newly discovered, remote territory, requires the establishment of a base camp. Invitations have been extended

J. M. Beggs

1984-01-01

357

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

NASA Astrophysics Data System (ADS)

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

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

2010-05-01

358

Ferrar Dolerite Sill Emplacement Styles, Dry Valleys, Antarctica  

NASA Astrophysics Data System (ADS)

The Ferrar Dolerite of the Dry Valleys region of Antarctica, 100 km WNW of McMurdo Station, provides an unparalleled opportunity to examine both the physical and chemical characteristics of a magmatic plumbing system across a crustal depth range of several km. The mid-Jurassic Ferrar system consists of 4 distinct sill levels (100 to >300 m thick) and an extrusive component: the Kirkpatrick Basalt. The upper three sills (Mt. Fleming, Asgard, and Peneplain sills) intruded the Devonian-Triassic sedimentary section (the Beacon Sandstone). The lowermost sill (Basement sill) intruded Ordovician granite at a depth of ~3-4 km and is >330 m in thickness in places. The Basement sill is unique in this system in that: (1) It intruded into igneous rocks, resulting in sill geometries that are distinct from overlying sills that intruded along bedding planes; (2) It contains a laterally restricted, internally layered core of predominantly orthopyroxenite (the "Opx Tongue"); (3) Sill boundaries show evidence of initial brittle emplacement with subsequent thermal reintegration of sill walls in places, particularly adjacent to the Opx Tongue. The Basement sill intruded the granite from several to >100 m below the contact with the overlying sediments, defined by a Devonian erosional peneplain (the Kukri surface). Abutting relationships suggest that the Basement sill event postdated the overlying Peneplain sill. Emplacement features of the sills were examined along the walls of several valleys to characterize the styles of intrusion. At the W end of Wright Valley, the upper sills exhibit numerous vertical steps and jogs indicative of where adjacent sill segments intruded bedding planes at slightly different stratigraphic levels, then linked by fracturing through bridges of intervening host rock which became entrained within the sills. In contrast, a 7-km-long exposure of the Basement sill along the N wall of E Wright Valley maintains a fairly planar geometry. However, numerous vertical steps along the sill margins imply that intrusion here involved at least 10 initially separate sill segments that ultimately coalesced. Bent and rotated bridges at segment linkage points imply that nascent brittle fractures were intruded by magma, inducing an elastic host rock response during inflation. Adjacent segments linked together when the strength of intervening bridges was overcome. Theoretically, segmentation is most evident in planes orthogonal to the flow direction. The 3D geometry of segments and linkage features was somewhat discernable due to the slope of the valley walls and an ~ 65° angular range of cross-section views through the sill provided by topography. Analysis of such features imply magma transport through the sill segments along a N to NNE-trending axis. In Wright and Victoria valleys, the Basement sill transitions abruptly at the lateral tips into upward-feeding dikes. Such dike locations are consistent with theoretical predictions for a laccolith-like intrusion in an elastic body. The Opx Tongue only occurs in the thicker parts of the Basement sill, representing about 25% of the sill thickness. At least one lateral discontinuity in the tongue indicates that the linked sill segments at that location had already cooled sufficiently by the time of tongue emplacement that the liquid centers were disconnected; however, the tongue is continuous across other segment linkage points. The tongue thus appears to be a late-stage feature that was restricted to active magma channels within the partially cooled sill system. The tongue localizes between the center and upper margin of the sill, suggesting more rapid cooling through the base, perhaps due to the presence of an overlying heat source from the already present Peneplain sill.

Kattenhorn, S. A.

2005-12-01

359

Breakup of the Larsen Ice Shelf, Antarctica  

NASA Technical Reports Server (NTRS)

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

2002-01-01

360

Evaluation of turbulent fluxes over Maitri, Antarctica  

NASA Astrophysics Data System (ADS)

Turbulent fluxes have been evaluated for clear sunny days over the Indian Antarctic station, Maitri, using the basic meteorological data recorded at four levels of a 28 m tower. The data are supplemented with radiation data. The surface layer over Maitri remains thermally stratified during the hours of minimum solar insolation, the so-called nighttime period. The surface winds during this period are generally very strong resulting in high momentum fluxes. In particular, for high winds (>12 m s-1), the temperature gradient is found to be less positive than for moderate winds (4 to 7 m s-1). Solar insolation provided the daytime heating necessary for the diurnal variation of atmospheric stability, and hence, for the turbulent fluxes. Thus, on clear days daytime conditions are marked by upward transport of heat with reduced momentum flux, while stable nighttime conditions are marked by a downward heat flux with increased momentum fluxes.

Naithani, Jaya; Dutta, H. N.; Pasricha, P. K.; Reddy, B. M.; Aggarwal, K. M.

1995-04-01

361

Improving snow roads and airstrips in Antarctica  

NASA Astrophysics Data System (ADS)

During the 1986 to 1987 austral summer, snow road and runway test lanes were constructed at McMurdo Station and at South Pole Station. These lanes were monitored during Dec. 1986 to Jan. 1987, and again in Jan. 1988. Test sections were constructed of: (1) tractor-compacted snow topped with a 15 cm layer of rotary blower processed snow, (2) rotary processed and compacted snow in 15-cm layers to a depth of 60 cm, (3) rotary processed and compacted snow in 15-cm layers incorporating wood sawdust additive mixed at 5 percent by volume, and (4) rotary-processed snow with 10 percent sawdust by volume. These test sections were monitored by obtaining temperature and density profiles, Rammsonde hardness profiles, California Bearing Ratio and Clegg surface strength values, and testing for ability to withstand traffic. Wood sawdust added to processed snow in amounts of 5 to 10 percent by volume significantly increases the strength of the resulting snow road or runway. Adequate strengths of the snow/sawdust mixtures were achieved for limited use by wheeled C130 aircraft, but additional processing with heat, water or added compaction appears necessary to produce a 25-cm-thick surface layer adequate for frequent use and to accommodate wheeled C141 aircraft. At McMurdo, it was found that the sawdust was not effective in maintaining the integrity of the surface traffic during the thawing season without additional maintenance, whereas at the South Pole, thawing was not a problem since temperatures remained well below the melting point.

Lee, Sung M.; Haas, Wilbur M.; Brown, Robert L.; Wuori, Albert F.

1989-07-01

362

ECC (Electrochemical Concentration Cell) ozonesonde observations at Mirny, Antarctica, during 1988  

NASA Technical Reports Server (NTRS)

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

Komhyr, W. D.; Lathrop, J. A.; Arbuzova, V. N.; Khattatov, V. U.; Nureyev, P. G.; Rudakov, V. V.; Zamyshlayev, I. V.

1989-01-01

363

The space station  

NASA Technical Reports Server (NTRS)

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.

Munoz, Abraham

1988-01-01

364

Madrid space station  

NASA Technical Reports Server (NTRS)

The Madrid space station, operated under bilateral agreements between the governments of the United States and Spain, is described in both Spanish and English. The space station utilizes two tracking and data acquisition networks: the Deep Space Network (DSN) of the National Aeronautics and Space Administration and the Spaceflight Tracking and Data Network (STDN) operated under the direction of the Goddard Space Flight Center. The station, which is staffed by Spanish employees, comprises four facilities: Robledo 1, Cebreros, and Fresnedillas-Navalagamella, all with 26-meter-diameter antennas, and Robledo 2, with a 64-meter antenna.

Fahnestock, R. J.; Renzetti, N. A.

1975-01-01

365

Antarctica: Scientific Journeys from McMurdo to the Pole  

NSDL National Science Digital Library

As a "continent devoted to science," Antarctica offers countless opportunities for researchers from around the world to learn about the history and mechanics of the earth. Exploratorium's latest offering highlights the ice-covered continent and the scientists who have and are studying it. The site includes simple descriptions, exceptional photographs, maps, and learning tools. One unique highlight is an interactive animation of continental drift and breakup of the once super-continent Pangaea, which led to the formation of Antarctica. Other features include a field notes section and schedule of live online Webcasts with scientists straight from the South Pole. Everyone from students to professionals will find something on this site worth discovering.

2001-01-01

366

Synchronous climate changes in antarctica and the north atlantic  

PubMed

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

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

1998-10-01

367

Ozone hits low levels over Antarctica, U. S  

SciTech Connect

This year's Antarctic ozone hole is as deep as any ever observed and is approaching the record geographical extent of 1992, according to preliminary satellite data. In addition, both groundbased and satellite observations indicate that ozone concentrations over the U.S. hit record lows earlier this year. For more than a decade, almost all the ozone at certain altitudes over Antarctica has been destroyed as the Sun returns to the polar region in September. This dramatic photochemical depletion, catalyzed by chlorine and bromine from man-made compounds, reaches its nadir in early October. Ozone levels return to near normal later in the season, when the circular pattern of winds that isolates air over Antarctica breaks down, and ozone-rich air pours in from the north.

Zurer, P.

1993-10-04

368

Navigation in Antarctica Today: The Global Positioning System  

NSDL National Science Digital Library

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

369

Condensation nucleus size distribution at Mawson, Antarctica: Microphysics and chemistry  

NASA Astrophysics Data System (ADS)

This work examines the annual evolution of the condensation nucleus (CN) size distribution and its relationship with other aerosol microphysical and chemical parameters in the lower atmosphere over Antarctica. Good agreement is observed between the seasonal cycles of aerosol volume and non-sea-salt sulfate. Changes between periods with strong bimodality and periods with a weak or missing nucleus mode are interpreted in terms of a seasonally varying precursor sulfur source strength and aerosol surface area. Although there are very limited measurements of SO 2 concentration for this region, conditions under which these are consistent with the observed SO 4 levels are considered. Overall, the observed relationships between microphysical and chemical properties of the aerosol strongly support the notion that the dominant source of nuclei in remote southern locations, including Antarctica, is maritime and that these nuclei result from the oxidation of dimethyl sulfide to methane sulfonate and sulfate.

Gras, J. L.

370

Airborne laser scanning for high-resolution mapping of Antarctica  

NASA Astrophysics Data System (ADS)

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.

Csatho, Bea; Schenk, Toni; Krabill, William; Wilson, Terry; Lyons, William; McKenzie, Garry; Hallam, Cheryl; Manizade, Serdar; Paulsen, Timothy

371

The 1982 eruption of El Chichon volcano, southeastern Mexico ( Antarctica).  

USGS Publications Warehouse

Late in the evening on March 28, El Chichon roared into life with a tremendous explosion that sent a column of ash and gases 10 miles high within an hour. There were no immediate warning signals of the eruption of El Chichon, although increased earthquake activity had been noted for months, possibly a few years, before the explosion. Sound waves from the explosion were detected by instruments 7000 miles away in Antarctica.-after Author

Tilling, R.I.

1982-01-01

372

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.

373

Microbial uptake of dissolved organic matter in Mcmurdo Sound, Antarctica  

Microsoft Academic Search

The distribution and activity of bacterioplankton, and the turnover of dissolved organic matter (DOM) were examined in McMurdo Sound, Antarctica. On the eastern side of the Sound, bacteria averaged 6.5×108 l-1, and turnover rates of dissolved adenosine triphosphate, D-glucose and l-leucine averaged 16, 116 and 124 h, respecitvely. These molecules as well as thymidine were taken up maximally from 0°

R. E. Hodson; F. Azam; A. F. Carlucci; J. A. Fuhrman; D. M. Karl; O. Holm-Hansen

1981-01-01

374

Preservation of Miocene glacier ice in East Antarctica  

Microsoft Academic Search

ANTARCTIC climate during the Pliocene has been the subject of considerable debate. One view holds that, during part of the Pliocene, East Antarctica was largely free of glacier ice and that vegetation survived on the coastal mountains1á¤-4. An alternative viewpoint argues for the development of a stable polar ice sheet by the middle Miocene, which has persisted since then5á¤-10. Here

David E. Sugden; David R. Marchant; Noel Potter; Roland A. Souchez; George H. Denton; Carl C. Swisher III; Jean-Louis Tison

1995-01-01

375

Breakup and early seafloor spreading between India and Antarctica  

Microsoft Academic Search

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

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

2007-01-01

376

Crevasse detection with GPR across the Ross Ice Shelf, Antarctica  

Microsoft Academic Search

We have used 400-MHz ground penetrating radar (GPR) to detect crevasses within a shear zone on the Ross Ice Shcelf, Antarctica, to support traverse operations. The transducer was attached to a 6.5-m boom and pushed ahead of an enclosed tracked vehicle. Profile speeds of 4.8-11.3 km \\/ hr allowed real- time crevasse image display and a quick, safe stop when

Allan J. Delaney; Steve A. Arcone; A. O'Bannon; J. Wright

2004-01-01

377

Diversity of Soil Yeasts Isolated from South Victoria Land, Antarctica  

Microsoft Academic Search

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

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

2008-01-01

378

Heat shock response in psychrophilic and psychrotrophic yeast from Antarctica  

Microsoft Academic Search

The response to heat stress in six yeast species isolated from Antarctica was examined. The yeast were classified into two\\u000a groups: one psychrophilic, with a maximum growth temperature of 20°C, and the other psychrotrophic, capable of growth at temperatures\\u000a above 20°C. In addition to species-specific heat shock protein (hsp) profiles, a heat shock (15°C–25°C for 3 h) induced the\\u000a synthesis

Michelle L. Deegenaars; K. Watson

1998-01-01

379

SMOS over Antarctica - a short story of massive iceberg  

NASA Astrophysics Data System (ADS)

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.

Slominska, E.; Marczewski, W.; Slominski, J.

2012-04-01

380

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

NASA Astrophysics Data System (ADS)

A comprehensive account of the properties of southern hemisphere (SH) Polar Mesosphere Summer Echoes (PMSE) has been constrained by the lack of deployment of atmospheric radars. Here we present the first complete season of PMSE detected above the high-latitude station Davis, Antarctica (78.0°E, 68.6°S) using a 55-MHz atmospheric radar for the 2004-2005 austral summer. We present the characteristics and morphology of SH PMSE events observed during the interval 23 November 2004-18 February 2005. Coincident Aura satellite temperature measurements (T) and ground MF-radar partial reflection observations are used to investigate the thermal and dynamical state of the polar mesosphere during conditions of PMSE occurrence. We find that the seasonal envelope of PMSE corresponds remarkably well with the seasonal envelope of temperature or more precisely when T - Tfp < 0 K (Tfp = frost point temperature). Furthermore, we show that PMSE are linked with the typical summer equatorward flow of the mesosphere meridional wind, but were perturbed while this wind flowed poleward.

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

2007-03-01

381

Surface Velocity Time Series and Ice Flux of Glaciers on South Shetland Islands, Antarctica  

NASA Astrophysics Data System (ADS)

Island glaciers off the coast of the western Antarctic Peninsula are sensitive to climate change due to their small size and maritime climate. The temperature record at the Bellingshausen station (King George Island) shows an annual temperature trend of about 0.22 C/decade over the past 43 years. Currently there is limited information on the mass balance of glaciers surrounding Antarctica, and therefore there is a need for velocity data for these glaciers to calculate mass flux estimates as well as calibration and validation of models. In this study we observe the glacier surface velocities of major islands in the South Shetland Islands group using data from ALOS PALSAR imagery. These images provide a useful data set throughout the year, because SAR signals penetrate through clouds and acquire images independent of solar illumination. Image pairs are processed using the SAR feature tracking technique to obtain surface velocities between the first and second image acquisitions. Using least-squares inversion, multiple surface velocity measurements are converted into a time series, which is then analyzed for presence of seasonal variations in surface velocity. Based on average SAR surface velocities, ice thickness is estimated for selected glacier catchments based on Glen and Weertman (deformation and sliding) flow laws. The estimated ice thickness is compared with external measurements to estimate the accuracy of the method. Ice flux is then calculated at the flux gates for individual basins to provide an estimate of contribution to sea level rise from the study area.

Osmanoglu, B.; Braun, M.; Hock, R. M.; Navarro, F. J.; Corcuera, M.

2012-12-01

382

In situ radioglaciological measurements near Taylor Dome, Antarctica and implications for UHE neutrino astronomy  

E-print Network

Radiowave detection of the Cherenkov radiation produced by neutrino-ice collisions requires an understanding of the radiofrequency (RF) response of cold polar ice. We herein report on a series of radioglaciological measurements performed approximately 10 km north of Taylor Dome Station, Antarctica from Dec. 6, 2006 - Dec. 16, 2006. Using RF signals broadcast from: a) an englacial discone, submerged to a depth of 100 meters and broadcasting to a surface dual polarization horn receiver, and b) a dual-polarization horn antenna on the surface transmitting signals which reflect off the underlying bed and back up to the surface receiver, we have made time-domain estimates of both the real (index-of-refraction) and imaginary (attenuation length) components of the complex ice dielectric constant. We have also measured the uniformity of ice response along two orthogonal axes in the horizontal plane. We observe a wavespeed asymmetry of order 0.1%, projected onto the vertical propagation axis, consistent with some previous measurements, but somewhat lower than others.

D. Besson; J. Jenkins; S. Matsuno; J. Nam; M. Smith; S. W. Barwick; J. J. Beatty; W. R. Binns; C. Chen; P. Chen; J. M. Clem; A. Connolly; P. F. Dowkontt; M. A. DuVernois; R. C. Field; D. Goldstein; P. W. Gorham; A. Goodhue; C. Hast; C. L. Hebert; S. Hoover; M. H. Israel; J. Kowalski; J. G. Learned; K. M. Liewer; J. T. Link; E. Lusczek; B. Mercurio; C. Miki; P. Miocinovic; C. J. Naudet; J. Ng; R. Nichol; K. Palladino; K. Reil; A. Romero-Wolf; M. Rosen; L. Ruckman; D. Saltzberg; D. Seckel; G. S. Varner; D. Walz; F. Wu

2008-10-07

383

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

NASA Astrophysics Data System (ADS)

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

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

2012-06-01

384

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

NASA Astrophysics Data System (ADS)

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.

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

385

Climate Change at the Poles: Research Immersion Experience at Bellingshausen, Antarctica  

NASA Astrophysics Data System (ADS)

We brought a party of 15 scientists, graduate students, and educators to King George Island, the largest of the South Shetland Islands, just off the Antarctic Peninsula, for an international workshop on Antarctica and global climate change in January 2010. Participants included professors, young scientists and graduate students from the Obukhov Institute of Atmospheric Physics, the University of Maryland, the University of Wisconsin, and the Michigan Technological University. Lindsay Bartholomew, an education and outreach specialist at the Museum of Science and Industry in Chicago connected the workshop via video and Internet with an audience of museum visitors. Scientists living and working at Bellingshausen, including Hans-Ulrich Peter, an eminent ecologist from Jena University (Germany), and Bulat Movlyudov (Institute of Geography, Moscow), a distinguished glaciologist, participated in the workshop. Field trips led by Peter and Movlyudov and others were made by day and lectures were held by night. Professors and graduate students made cutting-edge presentations on such subjects as permafrost, glaciology, and global climate models. Three workshop teams conducted field research projects at the foot of the Bellingshausen Dome icecap - two on carbon cycling and one on permafrost. Major funding sources for the workshop included the Russian Foundation for Basic Research (Russia), Wilderness Research Foundation (USA), NSF, University of Wisconsin at Stevens Point, Alfred Wegener Institute (Germany) and Museum for Science and Industry (Chicago). INACH, the Chilean Antarctic Institute, and IAU, the Uruguayan Antarctic Institute, provided air charter services. On King George Island, our group was billeted at Russia’s Bellingshausen science station.

Alexeev, V. A.; Repina, I. A.; Baeseman, J. L.; Fernandoy, F.; Bart, S.

2010-12-01

386

Evaluation of DNA dosimetry to assess ozone-mediated variability of biologically harmful radiation in Antarctica.  

PubMed

In this study we investigated the use of a DNA dosimeter to accurately measure changes in ultraviolet B radiation (UVBR; 280-315 nm) under Antarctic ozone hole conditions. Naked DNA solution in quartz tubes was exposed to ambient solar radiation at Rothera Research Station, Antarctica, between October and December 1998 for 3 h during UVBR peak hours (1200-1500 h). Trends in UVBR-mediated DNA damage (formation of cyclobutane pyrimidine dimers [CPD]) were related to cloud cover, ozone-column depth and spectroradiometric measurements of ambient radiation. Ozone-column depths ranged from 130 to 375 DU during the study period, resulting in highly variable UVBR doses, from 1.6 to 137 kJ m(-2) over the 3 h exposure, as measured by spectroradiometry. There was a strong positive correlation (86%) between dosimeter CPD concentrations and DNA-weighted UVBR doses. Ozone depth was a strong predictor of DNA damage (63%), and there was no significant relationship between CPD formation and cloud cover. Subtle changes in spectral characteristics caused by ozone depletion were detected by the biodosimeter; the highest CPD concentrations were observed in October when ozone-mediated shifts favored shorter wavelengths of UVBR. We conclude that the DNA biodosimeter is an accurate indicator of biologically effective UVBR, even under highly variable ozone conditions. PMID:12403448

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

2002-09-01

387

Scavenging of atmospheric ions and aerosols by drifting snow in Antarctica  

E-print Network

Measurements of the small,intermediate, and large ion concentrations and the airearth current density along with simultaneous measurements of the concentration and size-distribution of aerosol particles in the size ranges 4.4 to 163 nm and 0.5 to 20 micrometer diameters are reported for a drifting snow period after the occurrence of a blizzard at a coastal station, Maitri, Antarctica. Ion concentrations of all categories and the airearth current simultaneously decrease by approximately an order of magnitude as the wind speed increases from 5 to 10 meter per sec. The rate of decrease is the highest for large ions, lowest for small ions and in between the two for intermediate ions. Total aerosol number concentration decreases in the 4.4 to 163 nm size range but increases in 0.5 to 20 micrmetr size range with wind speed. Size distribution of the nanometer particles show a dominant maximum at 30 nm diameter throughout the period of observations and the height of the maximum decreases with wind speed. However, lar...

Kamra, A K; Pant, Vimlesh; 10.1016/j.atmosres.2008.02.018

2009-01-01

388

Particulate and dissolved iron sources in the Amundsen Sea, Western Antarctica  

NASA Astrophysics Data System (ADS)

The Amundsen Sea, Western Antarctica, includes one of the most productive polynyas of the Southern Ocean, where summer primary production can reach up to 3 g C m-2 d-1. The Oden Southern Ocean 2007-08 Joint US-Swedish expedition to the Amundsen and Ross Seas provided an opportunity to study the trace metal composition in these productive waters. Concentrations of particulate (0.45-5?m, and >5?m) and dissolved iron (<0.2?m) were investigated in sections spanning offshore ACC waters to coastal shelf waters with different ice coverage. Both particulate and dissolved analyses were performed on a HR-ICP-MS using novel methods. Particulate metal concentrations were lowest in stations north of the Amundsen Sea and highest adjacent to the Amundsen Sea ice shelves, up to 150 nmol L-1 near the Crosson ice shelf. Data from the Ross Sea and from the Antarctic Peninsula are also presented as a way of comparison. In light of these results, it is suggested that ice shelves and sediment resuspension dominate the Fe inputs to the phytoplankton community, however, the mechanisms and transformations governing the bioavailability of the particulate iron are yet to be resolved.

Planquette, H.; Sherrell, R. M.; Stammerjohn, S. E.; Séguret, M.; Field, M. P.

2010-12-01

389

Observations of Correlated Ozone Depletion Events and Sub-micron Particle Enhancements in Coastal Antarctica  

NASA Astrophysics Data System (ADS)

In the Austral spring of 2007 and 2012, trace gases, sub-micron particle size distributions, bulk filterable halogen content, and meteorological parameters were measured on Ross Island near McMurdo Station, Antarctica. During several surface-level ozone depletion events (ODE), enhanced sub-micron particle concentrations and changes in filterable halogens and sulfate aerosols were observed. These events were characterized by ozone depletions of 5 - 15 ppbv from backgrounds ranging from 25 - 35 ppbv for durations between 6 and 48 hours, and were associated with three-to-four-fold increases in sub-micron particle mass (PM1.0) over backgrounds of approximately 0.1 ?g m-3. Particle enhancement was primarily in a size mode centered around an optical diameter of 600nm, which is consistent with winter time sea salt aerosol size distributions. Filterable chloride and sulfate increased during these events, consistent with aerosol being of oceanic origin. Ozone depletion and particle enhancement events were accompanied by increasing temperatures and higher wind speeds, which suggests that halogen-containing aerosol is generated from wind-blown snow and brine from the snow pack or sea ice near the ice edge. These initial observations suggest a connection between polar tropospheric ozone depletion and physical or chemical aerosol processes and further observations are planned to investigate this relationship.

Kalnajs, L.; Avallone, L. M.; Toohey, D. W.

2013-12-01

390

Molecular characterisation of anthropogenic sources of sedimentary organic matter from Potter Cove, King George Island, Antarctica.  

PubMed

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

Dauner, Ana Lúcia L; Hernández, Edgardo A; MacCormack, Walter P; Martins, César C

2015-01-01

391

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

USGS Publications Warehouse

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.

Shearn-Bochsler, Valerie; Green, David Earl; Converse, K.A.; Docherty, D.E.; Thiel, T.; Geisz, H.N.; Fraser, W.R.; Patterson-Fraser, D. L.

2008-01-01

392

A new species of Laonice (Spionidae, Polychaeta, Annelida) from Bellingshausen Sea (West Antarctica)  

NASA Astrophysics Data System (ADS)

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.

López, Eduardo

2011-06-01

393

Radiosonde observations of gravity waves in the lower stratosphere over Davis, Antarctica  

NASA Astrophysics Data System (ADS)

Radiosonde observations made from Davis station, Antarctica, (68.6°S, 78.0°E) between 2001 and 2012 are used to compile a climatology of lower stratosphere inertial gravity wave characteristics. Wavelet analysis extracts single wave packets from the wind and temperature perturbations. Wavelet parameters, combined with linear gravity wave theory, allow for the derivation of a wide range of wave characteristics. Observational filtering associated with this analysis preferentially selects inertial gravity waves with vertical wavelengths less than 2-3 km. The vertical propagation statistics show strong temporal and height variations. The waves propagate close to the horizontal and are strongly advected by the background wind in the wintertime. Notably, around half of the waves observed in the stratosphere above Davis between early May and mid-October propagate downward. This feature is distributed over the observed stratospheric height range. Based on the similarity between the upward and downward propagating waves and on the vertical structure of the nonlinear balance residual in the polar winter stratosphere, it is concluded that a source due to imbalanced flow that is distributed across the winter lower stratosphere best explains the observations. Calculations of kinetic and potential energies and momentum fluxes highlight the potential for variations in results due to different analysis techniques.

Murphy, D. J.; Alexander, S. P.; Klekociuk, A. R.; Love, P. T.; Vincent, R. A.

2014-11-01

394

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

NASA Astrophysics Data System (ADS)

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

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

2004-05-01

395

Long-term conservation of viable microorganisms in the ice sheet of Central Antarctica  

NASA Astrophysics Data System (ADS)

Many investigators regard Antarctica as a model for solution of such problems as search of life on other planets, the quarantine in planets, and at the Earth during interplanetary contacts. It is also a good natural experiment for studying the phenomenon of microbial long- term anabiosis. Remoteness from the regions of intensive anthropogenic effects, low stable temperature and reliable protection of ancient ice horizons against subsequent environmental changes make Antarctic ice sheet an ideal object for methodological works necessary for investigation of various problems of exobiology. Investigations of ice bodies in attempts to find there any possible form of life has an advantage over similar studies of other cosmic solids because microorganisms, spores, plant pollen, unicellular algae, and other inclusions rather easily release from the melted ice and their investigation by different methods depends only on the well thought-out techniques. Special techniques of aseptic sampling while drilling at Vostok station and analysis of these samples by different methods have provided evidence for the existence of viable microorganisms in very ancient layers of the ice sheet. The relationship between quantitative distribution of microbes at different horizons of the ice column with the Earth's climate fluctuations at the time of these layers formation was also demonstrated.

Abyzov, Sabit S.; Mitskevich, Irina N.; Poglazova, Margarita N.; Barkov, Nartsiss I.; Lipenkov, Vladimir Y.; Bobin, Nikita E.; Koudryashov, Boris B.; Pashkevich, Victor M.

1998-07-01

396

Soil formation in Seymour Island, Weddell Sea, Antarctica  

NASA Astrophysics Data System (ADS)

The Antarctic Peninsula marks the climatic transition between Maritime and Continental Antarctica. Ice-free areas at the western side of the Peninsula (Maritime Antarctica) have been increasingly studied in the last 10 years whereas soils on the eastern coast have been relatively less studied. The objective of the present study is to analyze the properties of soils developed on Seymour Island, in the Weddell sea sector, eastern coast of the Antarctic Peninsula, in order to identify the main factors and processes involved in soil formation under semi-polar desert conditions in this part of Antarctica. Twenty-one pedons were described, sampled and analyzed for their physical, chemical and mineralogical attributes. Most of the soils were classified as Gelisols and Cryosols by the Soil Taxonomy and WRB/FAO, respectively. Three soil groups were found: immature alkaline soils on sandstones and siltstones, acid sulfate and ornithogenic soils. Soils have little cryoturbation and are all affected by salinization with natric and salic characters. Acid sulfate soils are the most weathered soils in Seymour Island. Due to the dry climate, phosphatization is still incipient with P-rich ornithogenic layers with little interaction with the mineral substrate. The Soil Taxonomy and WRB/FAO systems lack adequate classification criteria to classify all soils developed in transitional areas that are affected by a combination of salinization, sulfurization and phosphatization.

Souza, Katia Karoline Delpupo; Schaefer, Carlos Ernesto G. R.; Simas, Felipe Nogueira Bello; Spinola, Diogo Noses; de Paula, Mayara Daher

2014-11-01

397

Antarctica's protected areas are inadequate, unrepresentative, and at risk.  

PubMed

Antarctica is widely regarded as one of the planet's last true wildernesses, insulated from threat by its remoteness and declaration as a natural reserve dedicated to peace and science. However, rapidly growing human activity is accelerating threats to biodiversity. We determined how well the existing protected-area system represents terrestrial biodiversity and assessed the risk to protected areas from biological invasions, the region's most significant conservation threat. We found that Antarctica is one of the planet's least protected regions, with only 1.5% of its ice-free area formally designated as specially protected areas. Five of the distinct ice-free ecoregions have no specially designated areas for the protection of biodiversity. Every one of the 55 designated areas that protect Antarctica's biodiversity lies closer to sites of high human activity than expected by chance, and seven lie in high-risk areas for biological invasions. By any measure, including Aichi Target 11 under the Convention on Biological Diversity, Antarctic biodiversity is poorly protected by reserves, and those reserves are threatened. PMID:24936869

Shaw, Justine D; Terauds, Aleks; Riddle, Martin J; Possingham, Hugh P; Chown, Steven L

2014-06-01

398

Space station data flow  

NASA Technical Reports Server (NTRS)

The results of the space station data flow study are reported. Conceived is a low cost interactive data dissemination system for space station experiment data that includes facility and personnel requirements and locations, phasing requirements and implementation costs. Each of the experiments identified by the operating schedule is analyzed and the support characteristics identified in order to determine data characteristics. Qualitative and quantitative comparison of candidate concepts resulted in a proposed data system configuration baseline concept that includes a data center which combines the responsibility of reprocessing, archiving, and user services according to the various agencies and their responsibility assignments. The primary source of data is the space station complex which provides through the Tracking Data Relay Satellite System (TDRS) and by space shuttle delivery data from experiments in free flying modules and orbiting shuttles as well as from the experiments in the modular space station itself.

1972-01-01

399

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

NASA Astrophysics Data System (ADS)

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

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

2010-09-01

400

Report on the First International Symposium on Operational Weather Forecasting in Antarctica.  

NASA Astrophysics Data System (ADS)

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.

Turner, John; Pendlebury, Stephen; Cowled, Lance; Jacka, Kieran; Jones, Marjorie; Targett, Philip

2000-01-01

401

Backyard Weather Stations  

NSDL National Science Digital Library

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

Randall, Dennis.

402

Weather Stations: Winds  

NSDL National Science Digital Library

In this activity, learners use a toaster to generate wind and compare the appliance's heat source to Jupiter's own hot interior. Learners discover that convection drives wind on Jupiter and on Earth. This activity is one station that can be combined with other stations for an hour and half lesson on weather patterns on Jupiter and Earth. For safety reasons, this activity should be facilitated by an adult or used as a demonstration only.

Institute, Lunar A.; Nasa

2011-01-01

403

Space Stations: Measure Up!  

NSDL National Science Digital Library

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.

Dr. Diane Byerly

2006-01-01

404

Progressive Cenozoic cooling and the demise of Antarctica’s last refugium  

PubMed Central

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

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

405

[Reply to ``Space Station?'' by L. H. Meredith] Way station  

Microsoft Academic Search

I agree with Les Meredith's statement of valid and nonvalid objectives for the space station. The problem with the space station that NASA is proposing is that it is designed to a nonvalid objective, specifically microgravity experimentation. I would support a space station that addressed the valid objective of a way station, but I cannot support NASA's current design.Meredith states

Jeffrey L. Warner

1987-01-01

406

Anthropometric characteristics of men in Antarctica.  

PubMed

Thirty anthropometric and ten physiological parameters were evaluated over a 10-month period during 1985-86 in 66 polar explorers at an Antarctic station (Mirny observatory), all of them males aged 25-61 years. The evaluations were made in the months of April, September and January, which corresponded to the following Antarctic seasons: the beginning of the polar night, an intermediate period, and the beginning of the polar day; the necessary measurements were performed on subjects belonging to three occupational groups, namely: administrative, scientific, and manual workers. Significant changes in the pattern of skinfold thickness were observed using ANOVA with repeated measurements during the winter period (p < 0.05). Despite the fact that body weight and BMI of subjects remained unchanged, the mean sum of skinfold thickness and subcutaneous fat mass increased over the studied period at the expense of muscle mass. In participants engaged in high levels of outdoor physical activity (e.g. construction workers, drivers, technicians), an increase in fat mass, significant fall in muscle mass on wrist dynamometry, and protracted time of the simple motor response time was documented. Systolic blood pressure showed a downward trend during the winter in the group of manual workers, while significant rises in the diastolic pressure (p < 0.05) were found in the group of scientists at the end of the polar night. The present findings may be interpreted as evidence for destabilization in the studied individuals, and for an adaptation response to the Antarctic environment, which results in apparent increase in body fat and decrease in muscle mass. PMID:10528466

Belkin, V; Karasik, D

1999-07-01

407

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

NASA Astrophysics Data System (ADS)

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.).

Keskin, Siddik Sinan

408

Seismic monitoring at Deception Island volcano (Antarctica): the 2010-2011 survey  

NASA Astrophysics Data System (ADS)

As an example of the recent advances introduced in seismic monitoring of Deception Island volcano (Antarctica) during recent years, we describe the instrumental network deployed during the 2010-2011 survey by the Instituto Andaluz de Geofísica of University of Granada, Spain (IAG-UGR). The period of operation extended from December 19, 2010 to March 5, 2011. We deployed a wireless seismic network composed by four three-component seismic stations. These stations are based on 24-bit SL04 SARA dataloggers sampling at 100 sps. They use a PC with embedded linux and SEISLOG data acquisition software. We use two types of three-component seismometers: short-period Mark L4C with natural frequency of 1 Hz and medium-period Lennartz3D/5s with natural frequency of 0.2 Hz. The network was designed for an optimum spatial coverage of the northern half of Deception, where a magma chamber has been reported. Station locations include the vicinity of the Spanish base "Gabriel de Castilla" (GdC), Obsidianas Beach, a zone near the craters from the 1970 eruptions, and the Chilean Shelter located south of Pendulum Cove. Continuous data from the local seismic network are received in real-time in the base by wifi transmission. We used Ubiquiti Networks Nanostation2 antennas with 2.4 GHz, dual-polarity, 10 dBi gain, and 54 Mbps transmission rate. They have shown a great robustness and speed for real-time applications. To prioritize data acquisition when the battery level is low, we have designed a circuit that allows independent power management for the seismic station and wireless transmission system. The reception antenna located at GdC is connected to a computer running SEISCOMP. This software supports several transmission protocols and manages the visualization and recording of seismic data, including the generation of summary plots to show the seismic activity. These twelve data channels are stored in miniseed format and displayed in real time, which allows for a rapid evaluation of the seismic activity and an efficient seismo-volcanic surveillance. The data are processed and analyzed using the SEISAN database management software. In addition to the seismic network, we deployed a small-aperture seismic array south of Fumarole Bay. It is composed by 9 vertical and 1 three-component short-period stations. The 24-bit data acquisition system samples these 12 channels at 100 sps. There is also a permanent seismic station operating since 2008 and located near GdC, that is very useful for the preliminary evaluation of the seismicity at the start of the survey. This station is composed by a 16-s electrolytic seismometer (Eentec SP400) and a 24-bit datalogger (Eentec DR4000) sampling at 100 sps. During the 2010-2011 survey we identified 33 regional earthquakes, 80 volcano-tectonic (VT) earthquakes, and 929 long-period (LP) events. The volcanic alert system has remained green (the lowest level) at all times. The seismic activity has been similar to previous surveys and remained within limits that are normal for the island.

Martín, R.; Carmona, E.; Almendros, J.; Serrano, I.; Villaseñor, A.; Galeano, J.

2012-04-01

409

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

E-print Network

ESTIMATION OF SNOW ACCUMULATION IN ANTARCTICA USING AUTOMATED ACOUSTIC DEPTH GAUGE MEASUREMENTS microwave sounders, snow gauges, or radar are not feasible or not available in Antarctica at the present time. Consequently, the amount of accumulation at a given site, whether by blowing snow or falling

Wisconsin at Madison, University of

410

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

E-print Network

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, we present and recommend, depending on available logistical support, three tech- niques of snow

Paris-Sud XI, Université de

411

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

E-print Network

International Snow Science Workshop Grenoble ­ Chamonix Mont-Blanc - 2013 Simulations of blowing 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

Paris-Sud XI, Université de

412

Antarctica: The Continuing Experiment. Foreign Policy Association Headline Series, No. 273.  

ERIC Educational Resources Information Center

One of a series of booklets on world issues examines the sharpened differences between those nations that have declared sovereignty over parts of Antarctica and those that have not; between those nations that have arbitrarily assumed responsibility for the administration of Antarctica and the smaller, more numerous nations that believe their…

Quigg, Philip W.

413

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

414

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

E-print Network

Climatology of katabatic winds in the McMurdo dry valleys, southern Victoria Land, Antarctica December 2003; published 14 February 2004. [1] Katabatic winds dramatically affect the climate of the McMurdo dry valleys, Antarctica. Winter wind events can increase local air temperatures by 30°C. The frequency

Fountain, Andrew G.

415

Modeled methanesulfonic acid (MSA) deposition in Antarctica and its relationship to sea ice  

E-print Network

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

Holmes, Christopher D.

416

Survival and Recovery of Phaeocystis Antarctica (Prymnesiophyceae) from Prolonged Darkness and Freezing  

EPA Science Inventory

The colony-forming haptophyte Phaeocystis antarctica is an important primary producer in the Ross Sea, and must survive long periods of darkness and freezing in this extreme environment. We conducted experiments on the responses of P. antarctica-dominated phytoplankton assemblage...

417

Antarctica: King of Cold:Grades K-1:Text Only Version  

NSDL National Science Digital Library

This informational text explains that while both the Arctic and Antarctica are cold, Antarctica is much colder and drier - a polar desert. The text is written at a kindergarten through grade one reading level. This is a PDF containing the informational text and a glossary

Fries-Gaither, Jessica

418

Holocene Climate Variability in Antarctica Based on 11 Ice-Core Isotopic Records  

Microsoft Academic Search

A comparison is made of the Holocene records obtained from water isotope measurements along 11 ice cores from coastal and central sites in east Antarctica (Vostok, Dome B, Plateau Remote, Komsomolskaia, Dome C, Taylor Dome, Dominion Range, D47, KM105, and Law Dome) and west Antarctica (Byrd), with temporal resolution from 20 to 50 yr. The long-term trends possibly reflect local

Valérie Masson; Françoise Vimeux; Jean Jouzel; Vin Morgan; Marc Delmotte; Philippe Ciais; Claus Hammer; Sigfus Johnsen; Vladimir Ya. Lipenkov; E. Mosley-Thompson; Jean-Robert Petit; Eric J. Steig; Michel Stievenard; Rein Vaikmae

2000-01-01

419

Homogeneous climate variability across East Antarctica over the past three glacial cycles  

Microsoft Academic Search

Recent ice core studies have raised the disturbing possibility that glacial-interglacial climate changes may be non-uniform across Antarctica. These findings have been confined to records from the Ross Sea sector of the continent, but significant deviations in other areas would call into question the widely assumed validity of the climate record obtained from Vostok, East Antarctica, on large spatial scales.

O. Watanabe; J. Jouzel; S. Johnsen; F. Parrenin; H. Shoji; N. Yoshida

2003-01-01

420

Rapid Cenozoic glaciation of Antarctica induced by declining atmospheric CO2  

Microsoft Academic Search

The sudden, widespread glaciation of Antarctica and the associated shift towards colder temperatures at the Eocene\\/Oligocene boundary (~34 million years ago) (refs 1-4) is one of the most fundamental reorganizations of global climate known in the geologic record. The glaciation of Antarctica has hitherto been thought to result from the tectonic opening of Southern Ocean gateways, which enabled the formation

Robert M. DeConto; David Pollard

2003-01-01

421

Winter warming over Dome Fuji, East Antarctica and semiannual oscillation in the atmospheric circulation  

Microsoft Academic Search

An abrupt warming was observed in the winter around Dome Fuji (3810 m above sea level (asl)) in East Antarctica. The air temperature increased from -73°C to -36°C in two days, from June 13 to 14, 1994. Warming occurred first in the coastal region near the Lambert Glacier, East Antarctica, then progressed inland to Dome Fuji. During the warming, a

Hiroyuki Enomoto; Hideaki Motoyama; Takayuki Shiraiwa; Takashi Saito; Takao Kameda; Teruo Furukawa; Shuhei Takahashi; Yuji Kodama; Okitsugu Watanabe

1998-01-01

422

Differential accumulation of dehydrin-like proteins by abiotic stresses in Deschampsia antarctica Desv  

Microsoft Academic Search

Dehydrins are proteins that accumulate during environmental stresses leading to cell dehydration. Deschampsia antarctica is one of the two vascular plants that have colonized the Maritime Antarctic. This plant is usually exposed to cold, salt and desiccating winds in the field. We proposed that among the factors that allow D. antarctica to survive the harsh environmental conditions is the presence

Nélida Olave-Concha; León A. Bravo; Simón Ruiz-Lara; Luis J. Corcuera

2005-01-01

423

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...

424

Return to Coalsack Bluff and the Permian Triassic boundary in Antarctica  

Microsoft Academic Search

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

Gregory J. Retallack; Tara Greaver; A. Hope Jahren

2007-01-01

425

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...

426

Certified Reference Materials for Research in Antarctica: The Case of Marine Sediment  

Microsoft Academic Search

A multielemental certified reference material based on Antarctic marine sediment was prepared in the framework of the Italian Programma Nazionale per la Ricerca in Antartide (PNRA, National Program for Research in Antarctica) and was coordinated by the Istituto Superiore di Sanità (ISS, National Institute of Health). The sediment was collected during the 9th Italian Expedition (1993–1994) in Antarctica in Terra

S. Caroli; O. Senofonte; S. Caimi; P. Robouch; J. Pauwels; G. N. Kramer

1998-01-01

427

Performance of bismuth germanate active shielding on a balloon flight over Antarctica  

SciTech Connect

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.

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

428

ILRS Station Reporting  

NASA Technical Reports Server (NTRS)

Network stations provided system configuration documentation upon joining the ILRS. This information, found in the various site and system log files available on the ILRS website, is essential to the ILRS analysis centers, combination centers, and general user community. Therefore, it is imperative that the station personnel inform the ILRS community in a timely fashion when changes to the system occur. This poster provides some information about the various documentation that must be maintained. The ILRS network consists of over fifty global sites actively ranging to over sixty satellites as well as five lunar reflectors. Information about these stations are available on the ILRS website (http://ilrs.gsfc.nasa.gov/network/stations/index.html). The ILRS Analysis Centers must have current information about the stations and their system configuration in order to use their data in generation of derived products. However, not all information available on the ILRS website is as up-to-date as necessary for correct analysis of their data.

Noll, Carey E.; Pearlman, Michael Reisman; Torrence, Mark H.

2013-01-01

429

CryoSat-2 validation in East Antarctica: ASIRAS, ALS and in situ data analysis over Law Dome and Totten Glacier  

NASA Astrophysics Data System (ADS)

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.

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

430

Multi-decadal surface temperature trends near the Ice Divide of East Antarctica using borehole firn temperature measurements and inversion method  

NASA Astrophysics Data System (ADS)

The objective of this investigation is to detect multi-decadal surface temperature trends near the Ice Divide of East Antarctica. The interior of East Antarctic Ice Sheet (EAIS) remains as one of the least explored areas on earth. In recent years there have been several studies attempting to reconstruct the surface temperature history of Antarctica for the past 50 years using several approaches. However the lack of in situ data has hindered the science community in reaching a conclusive answer about Antarctic climate change, and in particular for the EAIS. In order to gain a better assessment of Antarctic climate change, additional data sources are needed to reduce the current uncertainty. Surface temperature inversion from firn temperature measurements will provide a source of climate reconstruction independent of firn chemistry, sparse weather data, satellite data or ice cores. During the Norwegian-U.S. IPY Scientific Traverse of East Antarctica, in austral summer of 2007-08, thermal-profiling units were installed at three locations (76.06 ° S, 22.46 ° E, Traverse site NUS07-2; 78.65 ° S, 35.64 ° E, NUS07-5, 126 km from Plateau Station; 82.07 ° S, 54.9 ° E, NUS07-7, 2 km from the Pole of Inaccessibility). Each unit consists of 16 PRTs (Platinum Resistance Thermometers) distributed between 0.2 and 90 m in depth. Wired PRTs were lowered into the borehole after an ice core was drilled and before the hole was back-filled with granulated snow to prevent air circulation and provide thermal conduction between PRTs and firn. Near-hourly data are being transmitted through ARGOS satellite telemetry system. The overall uncertainty in firn temperature measurement is between 0.02 and 0.03 ° C. Mean temperature gradients between -0.5 and -0.75 ° C were found between 16 and 90 m at three sites, with standard deviations less then 0.03 ° C. These gradients are larger than or about the same as previously published studies that modeled temperature profile under a steady-state climatic condition. Our results suggest a cooling to no significant trend near the Ice Divide of East Antarctica for the past several decades. Detailed analysis with the application of inversion method is ongoing to determine how the observed signals in the temperature profiles translate in to magnitudes and temporal scales of the surface temperature trends. A positive temperature gradient, suggesting recent warming, was identified for the top of the Greenland ice sheet (Summit station) and will be discussed in comparison.

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

2008-12-01

431

Telerobot for space station  

NASA Technical Reports Server (NTRS)

The Flight Telerobotic Servicer (FTS), a multiple arm dexterous manipulation system, will aid in the assembly, maintenance, and servicing of the space station. Fundamental ideas and basic conceptual designs for a shuttle-based telerobot system have been produced. Recent space station studies provide additional concepts that should aid in the accomplishment of mission requirements. Currently, the FTS is in contractual source selection for a Phase B preliminary design. At the same time, design requirements are being developed through a series of robotic assessment tasks being performed at NASA and commercial installations. A number of the requirements for remote operation on the space station, necessary to supplement extravehicular activity (EVA), will be met by the FTS. Finally, technology developed for telerobotics will advance the state of the art of remote operating systems, enhance operator productivity, and prove instrumental in the evolution of an adaptive, intelligent autonomous robot.

Jenkins, Lyle M.

1987-01-01

432

All year round chemical composition of aerosol reaching the inner Antarctic Plateau (Dome C - East Antarctica)  

NASA Astrophysics Data System (ADS)

Since 2005, continuous, all-year-round aerosol sampling was carried out at Dome C (Central East Antarctica, 3233 m a.s.l., about 1100 km far from the coast-line), in the framework of Station Concordia project. Size-segregated aerosol samples were collected in summer and winter period by using different low- and medium-volume systems, including pre-selected cut-off samplers (with PM10, PM2.5 and PM1 heads) and multi-stage (Andersen 8-stage and Dekati 4-stage) impactors. Sampling resolution and volume range from 1 day to 1 month and from 2.3 to 12 m3/h respectively. Aerosol study at Dome C aims to improve our knowledge on present day source intensity, transport efficiency and pathways (including stratosphere-to-troposphere interchanges) of particles reaching internal sites of Antarctica and to understand size- and chemical-fractionation effects occurring during the transport (by comparison with coastal aerosol composition). Besides, more information on atmosphere-snow interaction, including depositional and post depositional processes, as well as the effect of sublimation/condensation processes on snow surface, improves the reconstruction of past atmosphere composition from EPICA-DC deep ice core, drilled in the same site. Here we report some results of 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. The atmospheric load in the summer is more than one order of magnitude lower than that measured in coastal sites and chemical composition is dominated by secondary aerosol, mainly originated by biological marine activity (S-cycle), and distributed in the finest aerosol fractions. H2SO4 from oxidation of biogenic DMS is the main component, while the contribution of HNO3 to the ionic budget is difficult to evaluate because of the re-emission into the atmosphere from the filter surface (acidic deposition). The ionic load was even lower in winter, when secondary biogenic aerosol decreases and larger particles from primary source (especially from sea spray) prevail. Sea spray plays a significant role in winter and spring aerosol, when more frequent and effective transport events from marine areas around Antarctica occur. In the same transport conditions, even relatively large dust content (as revealed by Ca2+ concentration) is measured in the Dome C aerosol. Longer observations performed with higher temporal resolutions, yield greater information about the relationship between atmospheric circulation patterns and the load and chemical composition of atmospheric aerosol reaching DC in different seasons. Fractionating effects leading to a reduction of sulphate/sodium ratio (used as marker of "frost flower" source) seem generally do not affect in a significant way the winter aerosol composition, even if few negative values of non-sea salt sulphate were calculated along the whole analyzed period. This evidence could show that sea spray aerosol from frost flower can reach the inner Antarctic plateau when particular transport processes occurs.

Udisti, R.; Becagli, S.; Castellano, E.; Cerri, O.; Marino, F.; Morganti, A.; Nava, S.; Rugi, F.; Severi, M.; Traversi, R.

2009-04-01

433

Caring Together: Activity Stations  

NSDL National Science Digital Library

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) â Project: Build It" unit of study.

Indianapolis, The C.

2006-01-01

434

Weather Stations: Phase Change  

NSDL National Science Digital Library

In this activity, learners observe the water cycle in action! Water vapor in a tumbler condenses on chilled aluminum foil — producing the liquid form of water familiar to us as rain and dew. Learners discuss how Jupiter's lack of a surface simplifies its water cycle. Learners then consider the roles ammonia and ammonia compounds play in Jupiter's more complicated atmosphere. This activity is one station that can be combined with other stations for an hour and half lesson on weather patterns on Jupiter and Earth.

2014-07-11

435

Solar power station  

SciTech Connect

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

Wenzel, J.

1982-11-30

436

The organized Space Station  

NASA Astrophysics Data System (ADS)

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

Lew, Leong W.

437

The organized Space Station  

NASA Technical Reports Server (NTRS)

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

Lew, Leong W.

1988-01-01

438

Spatial and Temporal variability in Dynamic Topography in East Antarctica  

NASA Astrophysics Data System (ADS)

Recent aerogeophysical exploration has provided novel views of the Gamburtsev Subglacial Mountains and the Wilkes and Aurora subglacial basins in East Antarctica. Reconstructing the evolution of East Antarctic topography through time is a critical next step for developing new coupled climate and ice sheet models (e.g. http://www.antscape.org/). Insights into tectonic and isostatic components driving the uplift of the Gamburtsevs have emerged from geophysical investigations and modeling (Ferraccioli et al., 2011, Nature). However, our knowledge of the larger-scale consequences of dynamic topography in East Antarctica remains poor compared to other continents. Seismic tomographic models provide a tool to derive large-scale models of convection in the Earth's mantle, which can then be used to reconstruct dynamic topography through time. By analyzing grids of global dynamic topography from present-day to 100 Ma based on the tomographic models S40RTS & S20RTS (Ritsema et al. 1999, 2011) we assess for the first time the potential space-time variability in dynamic topography in East Antarctica. We acknowledge that there are significant limitations when compared to similar studies over other continents, such as the relatively poor seismic resolution of the lithosphere and asthenosphere beneath East Antarctica and the lack of geological and geophysical data to constrain surface movements through time. However, currently available global datasets do reveal several new insights. Our models reveal that at ca 65 Ma the Gamburtsev Province and Dronning Maud Land regions were elevated. This was followed by at least 500 m of subsidence throughout the Cenozoic. The increased regional elevation likely facilitated ephemeral ice cap development in the early Cenozoic, which was followed by ice cap coalescence to form the East Antarctic Ice Sheet at ca 34 Ma. In contrast, a major and more rapid increase in elevation (up to 1,000 m) is observed over the Transantarctic Mountains (TAM) and the adjacent Wilkes Subglacial Basin, in particular over the last 15 Ma. Neogene dynamic topography in the TAM region may be related to the flow of warm mantle from the West Antarctic Rift System and/or the Balleny plume.

Anderson, L.; Ferraccioli, F.; Eagles, G.; Steinberger, B.; Ritsema, J.

2012-04-01

439

Advanced systems data for mapping Emperor Penguin habitats in Antarctica  

USGS Publications Warehouse

Commercial orbital sensor systems combined with other resource data from the U.S. Geological Survey National Civil Applications Program (NCAP) may offer an effective way of mapping Emperor penguin habitats and their response to regional climate change in Antarctica. This project examined these resources to determine their applicability for mapping Emperor penguin habitats to support the National Science Foundation. This work is especially significant to investigate satellite-based imaging as an alternative to intrusive in-the-field enumeration of Emperor penguins and the potential of applying these procedures to support The National Map (TNP).

Sanchez, Richard D.; Kooyman, Gerald L.

2004-01-01

440

Site testing in summer at Dome C, Antarctica  

NASA Astrophysics Data System (ADS)

We present summer site testing results based on DIMM data obtained at Dome C, Antarctica. These data were collected on the bright star Canopus during two 3-months summer campaigns in 2003-2004 and 2004-2005. We performed continuous monitoring of the seeing and the isoplanatic angle in the visible. We found a median seeing of 0.54'' and a median isoplanatic angle of 6.8''. The seeing appears to have a deep minimum around 0.4'' almost every day in late afternoon.

Aristidi, E.; Agabi, A.; Fossat, E.; Azouit, M.; Martin, F.; Sadibekova, T.; Travouillon, T.; Vernin, J.; Ziad, A.

2005-12-01

441

Site testing in summer at Dome C, Antarctica  

E-print Network

We present summer site testing results based on DIMM data obtained at Dome C, Antarctica. These data have been collected on the bright star Canopus during two 3-months summer campaigns in 2003-2004 and 2004-2005. We performed continuous monitoring of the seeing a nd the isoplanatic angle in the visible. We found a median seeing of 0.54 \\arcsec and a median isoplanatic angle of 6.8 \\arcsec. The seeing appears to have a deep minimum around 0.4 \\arcsec almost every day in late afternoon.