High-elevation synoptic radio array for detection of upward moving air-showers, deployed in the Antarctic mountains

Abstract The Antarctic continent has not warmed in the last seven decades, despite a monotonic increase in the atmospheric concentration of greenhouse gases. In this paper, we investigate whether the high orography of the Antarctic ice sheet (AIS) has helped delay warming over the continent. To that end, we contrast the Antarctic climate response to CO2-doubling with present-day orography to the response with a flattened AIS. To corroborate our findings, we perform this exercise with two different climate models. We find that, with a flattened AIS, CO2-doubling induces more latent heat transport toward the Antarctic continent, greater moisture convergence over the continent and, as a result, more surface-amplified condensational heating. Greater moisture convergence over the continent is made possible by flattening of moist isentropic surfaces, which decreases humidity gradients along the trajectories on which extratropical poleward moisture transport predominantly occurs, thereby enabling more moisture to reach the pole. Furthermore, the polar meridional cell disappears when the AIS is flattened, permitting greater CO2-forced warm temperature advection toward the Antarctic continent. Our results suggest that the high elevation of the present AIS plays a significant role in decreasing the susceptibility of the Antarctic continent to CO2-forced warming.

Download Full-text

Antarctic atmospheric transparency at infrared and millimetre wavelengths

Highlights of Astronomy ◽

10.1017/s1539299600022541 ◽

1992 ◽

Vol 9 ◽

pp. 579-579

Author(s):

John Bally

Keyword(s):

Near Infrared ◽

Polar Vortex ◽

High Elevation ◽

Moist Air ◽

Atmospheric Water ◽

Atmospheric Water Vapour ◽

The Earth ◽

Infrared Wavelengths ◽

The Antarctic ◽

Astrophysical Research

The Antarctic Plateau is the best site on Earth for astrophysical research from millimetre to near-infrared wavelengths. The low temperature, high elevation on top of the ice sheet, and the Polar Vortex, which blocks the infusion of moist air, result in extremely low column densities of atmospheric water vapour. These unique conditions may result in the clearest and darkest sky available from the surface of the Earth in this wavelength range.

Download Full-text

Bacterial diversity of autotrophic enriched cultures from remote, glacial Antarctic, Alpine and Andean aerosol, snow and soil samples

Biogeosciences ◽

10.5194/bg-6-33-2009 ◽

2009 ◽

Vol 6 (1) ◽

pp. 33-44 ◽

Cited By ~ 20

Author(s):

E. González-Toril ◽

R. Amils ◽

R. J. Delmas ◽

J.-R. Petit ◽

J. Komárek ◽

...

Keyword(s):

Bacterial Diversity ◽

Cultured Cells ◽

High Elevation ◽

Aerosol Sample ◽

Rrna Gene ◽

Antarctic Soil ◽

Cold Environments ◽

The Andes ◽

Enriched Cultures ◽

The Antarctic

Abstract. Four different communities and one culture of autotrophic microbial assemblages were obtained by incubation of samples collected from high elevation snow in the Alps (Mt. Blanc area) and the Andes (Nevado Illimani summit, Bolivia), from Antarctic aerosol (French station Dumont d'Urville) and a maritime Antarctic soil (King George Island, South Shetlands, Uruguay Station Artigas), in a minimal mineral (oligotrophic) media. Molecular analysis of more than 200 16S rRNA gene sequences showed that all cultured cells belong to the Bacteria domain. Phylogenetic comparison with the currently available rDNA database allowed sequences belonging to Proteobacteria Alpha-, Beta- and Gamma-proteobacteria), Actinobacteria and Bacteroidetes phyla to be identified. The Andes snow culture was the richest in bacterial diversity (eight microorganisms identified) and the marine Antarctic soil the poorest (only one). Snow samples from Col du Midi (Alps) and the Andes shared the highest number of identified microorganisms (Agrobacterium, Limnobacter, Aquiflexus and two uncultured Alphaproteobacteria clones). These two sampling sites also shared four sequences with the Antarctic aerosol sample (Limnobacter, Pseudonocardia and an uncultured Alphaproteobacteriaclone). The only microorganism identified in the Antarctica soil (Brevundimonas sp.) was also detected in the Antarctic aerosol. Most of the identified microorganisms had been detected previously in cold environments, marine sediments soils and rocks. Air current dispersal is the best model to explain the presence of very specific microorganisms, like those identified in this work, in environments very distant and very different from each other.

Download Full-text

Reflections on the anomalous ANITA events: the Antarctic subsurface as a possible explanation

Annals of Glaciology ◽

10.1017/aog.2020.19 ◽

2020 ◽

Vol 61 (81) ◽

pp. 92-98 ◽

Cited By ~ 4

Author(s):

Ian M. Shoemaker ◽

Alexander Kusenko ◽

Peter Kuipers Munneke ◽

Andrew Romero-Wolf ◽

Dustin M. Schroeder ◽

...

Keyword(s):

Phase Inversion ◽

Cosmic Ray ◽

High Energy ◽

Air Showers ◽

Radio Signals ◽

Subsurface Layers ◽

Balloon Experiment ◽

Antarctic Impulsive Transient Antenna ◽

Sole Criterion ◽

The Antarctic

AbstractThe Antarctic Impulsive Transient Antenna (ANITA) balloon experiment was designed to detect radio signals initiated by high-energy neutrinos and cosmic ray (CR) air showers. These signals are typically discriminated by the polarization and phase inversions of the radio signal. The reflected signal from CRs suffer phase inversion compared to a direct ‘tau neutrino’ event. In this paper, we study subsurface reflection, which can occur without phase inversion, in the context of the two anomalous up-going events reported by ANITA. It is found that subsurface layers and firn density inversions may plausibly account for the events, while ice fabric layers and wind ablation crusts could also play a role. This hypothesis can be tested with radar surveying of the Antarctic region in the vicinity of the anomalous ANITA events. Future experiments should not use phase inversion as a sole criterion to discriminate between down-going and up-going events, unless the subsurface reflection properties are well understood.

Download Full-text

POEMMA: Probe Of Extreme Multi-Messenger Astrophysics

EPJ Web of Conferences ◽

10.1051/epjconf/201921006008 ◽

2019 ◽

Vol 210 ◽

pp. 06008 ◽

Cited By ~ 3

Author(s):

John Krizmanic

Keyword(s):

High Energy ◽

Fluorescence Signal ◽

Air Showers ◽

Tau Neutrino ◽

High Energy Cosmic Rays ◽

Air Fluorescence ◽

Upward Moving ◽

The Universe ◽

Mission Profile ◽

Higher Sensitivity

Developed as a NASA Astrophysics Probe mission concept study, the Probe Of Extreme Multi-Messenger Astrophysics (POEMMA) science goals are to identify the sources of ultra-high energy cosmic rays (UHECRs) and to observe cosmic neutrinos above 20 PeV. POEMMA consists of two satellites flying in loose formation at 525 km altitudes. A novel focal plane design is optimized to observe the UV air fluorescence signal from extensive air showers (EASs) in a stereoscopic UHECR observation mode and the Cherenkov signals from EASs from UHECRs and neutrino-induced τ-leptons in an Earth-limb viewing mode. POEMMA is designed to achieve full-sky coverage and significantly higher sensitivity to the highest energy cosmic messengers compared to what have been achieved so far by ground-based experiments. POEMMA will measure the spectrum, composition, and full sky distribution of the UHECRs above 30 EeV to identify the most energetic cosmic accelerators in the universe and study the acceleration mechanism(s). POEMMA will also have sensitivity to cosmic neutrinos by observing the upward-moving air showers induced from tau neutrino interactions in the Earth. POEMMA will also be able to re-orient to a Target-of-Opportunity (ToO) neutrino mode to view transient astrophysical sources with unique sensitivity. This paper discusses the science goals, instrument design, mission profile, and the simulated UHECR and neutrino measurement capabilities for POEMMA.

Download Full-text

Results from the third flight of ANITA

EPJ Web of Conferences ◽

10.1051/epjconf/201921601009 ◽

2019 ◽

Vol 216 ◽

pp. 01009

Author(s):

Abigail Vieregg

Keyword(s):

Cosmic Rays ◽

Radio Emission ◽

High Energy ◽

Neutrino Interaction ◽

Air Showers ◽

The Third ◽

Long Duration ◽

Antarctic Impulsive Transient Antenna ◽

Ultra High Energy Neutrinos ◽

The Antarctic

We summarize results from the third flight of the Antarctic Impulsive Transient Antenna (ANITA), a NASA long-duration balloon payload that searches for radio emission from the interactions of ultra-high-energy neutrinos and cosmic rays. ANITAIII was launched in December 2014 and flew for 22 days. We report the results from multipleanalyses of the data, which search for Askaryan radio emission from neutrinos interacting in the Antarctic ice as well as geomagnetic radio emission from extensive air showers (EASs) induced by cosmic rays or a tau lepton created in an in-earth tau neutrino interaction. In the most sensitive Askaryan neutrino search, we find one eventon a pre-unblinding background of 0:7−0:3+0.5. Across all searches, including a dedicated EAS search, we find a total of 28 EAS-like events. One of these events is consistent with an upward-traveling EAS, with a post-unblinding background estimate of ⪷10−2.

Download Full-text

ARIANNA: Measurement of cosmic rays with a radio neutrino detector in Antarctica

EPJ Web of Conferences ◽

10.1051/epjconf/201921602008 ◽

2019 ◽

Vol 216 ◽

pp. 02008 ◽

Cited By ~ 1

Author(s):

Christian Glaser

Keyword(s):

Cosmic Rays ◽

Cosmic Ray ◽

Cost Effective ◽

Neutrino Detector ◽

Air Showers ◽

Ice Shelf ◽

Ross Ice Shelf ◽

Radio Signals ◽

Single Detector ◽

The Antarctic

The ARIANNA detector aims to detect neutrinos with energies above 1016 eV by instrumenting 0.5 Teratons of ice with a surface array of a thousand independent radio detector stations in Antarctica. The Antarctic ice is transparent to the radio signals caused by the Askaryan effect which allows for a cost-effective instrumentation of large volumes. Several pilot stations are currently operating successfully at the Moore’s Bay site (Ross Ice Shelf) and at the South Pole. As the ARIANNA detector stations are positioned at the surface, the more abundant cosmic-ray air showers are also measured and serve as a direct way to prove the capabilities of the detector. We will present measured cosmic rays and will show how the incoming direction, polarization and electric field of the cosmicray pulse can be reconstructed from single detector stations comprising 4 upward and 4 downward facing LPDA antennas.

Download Full-text

Marine diatoms in ice cores from the Antarctic Peninsula and Ellsworth Land, Antarctica – species diversity and regional variability

10.5194/tc-2021-160 ◽

2021 ◽

Author(s):

Dieter R. Tetzner ◽

Elizabeth R. Thomas ◽

Claire S. Allen

Keyword(s):

Antarctic Peninsula ◽

Temporal Distribution ◽

Ice Cores ◽

High Elevation ◽

Polar Regions ◽

Regional Variability ◽

Marine Diatoms ◽

The Andes ◽

Glacier Ice ◽

The Antarctic

Abstract. The presence of marine microfossils (diatoms) in glacier ice and ice cores has been documented from numerous sites in Antarctica, Greenland, as well as from sites in the Andes and the Altai mountains, and attributed to entrainment and transport by winds. However, their presence and diversity in snow and ice, especially in polar regions, is not well documented and still poorly understood. Here we present the first data to resolve the regional and temporal distribution of diatoms in ice cores, spanning a 20 year period across four sites in the southern Antarctic Peninsula and Ellsworth Land, Antarctica. We assess the regional variability in diatom composition and abundance at annual and sub-annual resolution across all four sites. These data corroborate the dominance of contemporary marine diatoms in Antarctic Peninsula ice cores, reveal that the timing and amount of diatoms deposited vary between low and high elevation sites and support existing evidence that marine diatoms have the potential to yield a novel wind paleoenvironmental proxy for ice cores in the southern Antarctic Peninsula and Ellsworth Land.

Download Full-text

Remote Triggering of Icequakes at Mt. Erebus, Antarctica by Large Teleseismic Earthquakes

Seismological Research Letters ◽

10.1785/0220210027 ◽

2021 ◽

Author(s):

Chenyu Li ◽

Zhigang Peng ◽

Julien A. Chaput ◽

Jacob I. Walter ◽

Richard C. Aster

Keyword(s):

Austral Summer ◽

High Elevation ◽

Small Scale ◽

Volcano Observatory ◽

Seismic Triggering ◽

Stress Changes ◽

Before And After ◽

The Antarctic ◽

Erebus Volcano ◽

Large Earthquakes

Abstract Recent studies have shown that the Antarctic cryosphere is sensitive to external disturbances such as tidal stresses or dynamic stresses from remote large earthquakes. In this study, we systematically examine evidence of remotely triggered microseismicity around Mount (Mt.) Erebus, an active high elevation stratovolcano located on Ross Island, Antarctica. We detect microearthquakes recorded by multiple stations from the Mt. Erebus Volcano Observatory Seismic Network one day before and after 43 large teleseismic earthquakes, and find that seven large earthquakes (including the 2010 Mw 8.8 Maule, Chile, and 2012 Mw 8.6 Indian Ocean events) triggered local seismicity on the volcano, with most triggered events occurring during the passage of the shorter-period Rayleigh waves. In addition, their waveforms and locations for the triggered events are different when comparing with seismic events arising from the persistent small-scale eruptions, but similar to other detected events before and after the mainshocks. Based on the waveform characteristics and their locations, we infer that these triggered events are likely shallow icequakes triggered by dilatational stress perturbations from teleseismic surface waves. We show that teleseismic earthquakes with higher peak dynamic stress changes are more capable of triggering icequakes at Mt. Erebus. We also find that the icequakes in this study are more likely to be triggered during the austral summer months. Our study motivates the continued monitoring of Mount Erebus with dense seismic instrumentation to better understand interactions between dynamic seismic triggering, crospheric processes, and volcanic activity.

Download Full-text

Exposure-age data from across Antarctica reveal mid-Miocene establishment of polar desert climate

Geology ◽

10.1130/g47783.1 ◽

2020 ◽

Vol 49 (1) ◽

pp. 91-95

Author(s):

Perry Spector ◽

Greg Balco

Keyword(s):

Liquid Water ◽

High Elevation ◽

Polar Desert ◽

Cosmogenic Nuclide ◽

Erosion Processes ◽

Exposure Age ◽

Antarctic Continent ◽

The Antarctic ◽

Exposure Ages ◽

Desert Climate

Abstract High-elevation rock surfaces in Antarctica have some of the oldest cosmogenic-nuclide exposure ages on Earth, dating back to the Miocene. A compilation of all available 3He, 10Be, and 21Ne exposure-age data from the Antarctic continent shows that exposure histories recorded by these surfaces extend back to, but not before, the mid-Miocene cooling at 14–15 Ma. At high elevation, this cooling entailed a transition between a climate in which liquid water and biota were present and could contribute to surface weathering and erosion, and a polar desert climate in which virtually all weathering and erosion processes had been shut off. This climate appears to have continued uninterrupted between the mid-Miocene and the present.

Download Full-text