| Records |
| Author |
Ardhuin Fabrice, Stutzmann Eleonore, Schimmel Martin, Mangeney Anne, |
| Title |
Ocean wave sources of seismic noise
|
Type |
Journal Article |
| Year |
2011 |
Publication |
Journal of Geophysical Research: Oceans |
Abbreviated Journal |
J. Geophys. Res. |
| Volume |
116 |
Issue |
C9 |
Pages |
C09004- |
| Keywords |
directional wave spectra, ocean waves, seismic noise, wave model, 4259 Ocean acoustics, 4544 Internal and inertial waves, 4560 Surface waves and tides, 7220 Oceanic crust, 7255 Surface waves and free oscillations, |
| Abstract |
Noise with periods 3 to 10 s, ubiquitous in seismic records, is expected to be mostly generated by pairs of ocean wave trains of opposing propagation directions with half the seismic frequency. Here we present the first comprehensive numerical model of microseismic generation by random ocean waves, including ocean wave reflections. Synthetic and observed seismic spectra are well correlated (r > 0.85). On the basis of the model results, noise generation events can be clustered in three broad classes: wind waves with a broad directional spectrum (class I), sea states with a significant contribution of coastal reflections (class II), and the interaction of two independent wave systems (class III). At seismic stations close to western coasts, noise generated by class II sources generally dominates, but it is intermittently outshined by the intense class III sources, limiting the reliability of seismic data as a proxy for storm climates. The modeled seismic noise critically depends on the damping of seismic waves. At some mid-ocean island stations, low seismic damping is necessary to reproduce the observed high level and smoothness of noise time series that result from a spatial integration of sources over thousands of kilometers. In contrast, some coastal stations are only sensitive to noise within a few hundreds of kilometers. This revelation of noise source patterns worldwide provides a wealth of information for seismic studies, wave climate applications, and new constraints on the possible directional distribution of wave energy.
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133 |
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2156-2202 |
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Approved |
yes |
| Call Number |
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Serial |
845 |
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| Author |
Hezel P J, Alexander B, Bitz C M, Steig E J, Holmes C D, Yang X, Sciare J, |
| Title |
Modeled methanesulfonic acid (MSA) deposition in Antarctica and its relationship to sea ice
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Type |
Journal Article |
| Year |
2011 |
Publication |
Journal of Geophysical Research: Atmospheres |
Abbreviated Journal |
J. Geophys. Res. |
| Volume |
116 |
Issue |
D23 |
Pages |
D23214- |
| Keywords |
DMS, MSA, dimethylsulfide, ice core, methanesulfonic acid, sea ice, 0368 Troposphere: constituent transport and chemistry, 0750 Sea ice, 0793 Biogeochemistry, 3344 Paleoclimatology, |
| Abstract |
Methanesulfonic acid (MSA) has previously been measured in ice cores in Antarctica as a proxy for sea ice extent and Southern Hemisphere circulation. In a series of chemical transport model (GEOS-Chem) sensitivity experiments, we identify mechanisms that control the MSA concentrations recorded in ice cores. Sea ice is linked to MSA via dimethylsulfide (DMS), which is produced biologically in the surface ocean and known to be particularly concentrated in the sea ice zone. Given existing ocean surface DMS concentration data sets, the model does not demonstrate a strong relationship between sea ice and MSA deposition in Antarctica. The variability of DMS emissions associated with sea ice extent is small (1130%) due to the small interannual variability of sea ice extent. Wind plays a role in the variability in DMS emissions, but its contribution relative to that of sea ice is strongly dependent on the assumed DMS concentrations in the sea ice zone. Atmospheric sulfur emitted as DMS from the sea ice undergoes net transport northward. Our model runs suggest that DMS emissions from the sea ice zone may account for 2662% of MSA deposition at the Antarctic coast and 3695% in inland Antarctica. Though our results are sensitive to model assumptions, it is clear that an improved understanding of both DMS concentrations and emissions from the sea ice zone are required to better assess the impact of sea ice variability on MSA deposition to Antarctica.
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| Programme |
415 |
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| ISSN |
2156-2202 |
ISBN |
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Medium |
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Expedition |
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Conference |
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Approved |
yes |
| Call Number |
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Serial |
911 |
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| Author |
Jardon F P, Bouruet-Aubertot P, Cuypers Y, Vivier F, Lourenço A, |
| Title |
Internal waves and vertical mixing in the Storfjorden Polynya, Svalbard
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Type |
Journal Article |
| Year |
2011 |
Publication |
Journal of Geophysical Research: Oceans |
Abbreviated Journal |
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| Volume |
116 |
Issue |
C12 |
Pages |
C12040- |
| Keywords |
Garret and Munk model, Thorpe scale, barotropic tides, internal waves, latent heat polynya, vertical mixing, 4207 Arctic and Antarctic oceanography, 4544 Internal and inertial waves, 4572 Upper ocean and mixed layer processes, |
| Abstract |
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| Programme |
1015 |
| Campaign |
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| Address |
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| Corporate Author |
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Thesis |
Bachelor's thesis |
| Publisher |
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Place of Publication |
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Summary Language |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
2156-2202 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
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Approved |
yes |
| Call Number |
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Serial |
1114 |
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| |
| Author |
Hezel P J, Alexander B, Bitz C M, Steig E J, Holmes C D, Yang X, Sciare J, |
| Title |
Modeled methanesulfonic acid (MSA) deposition in Antarctica and its relationship to sea ice
|
Type |
Journal Article |
| Year |
2011 |
Publication |
Journal of Geophysical Research: Atmospheres |
Abbreviated Journal |
|
| Volume |
116 |
Issue |
D23 |
Pages |
D23214- |
| Keywords |
DMS, MSA, dimethylsulfide, ice core, methanesulfonic acid, sea ice, 0368 Troposphere: constituent transport and chemistry, 0750 Sea ice, 0793 Biogeochemistry, 3344 Paleoclimatology, |
| Abstract |
Methanesulfonic acid (MSA) has previously been measured in ice cores in Antarctica as a proxy for sea ice extent and Southern Hemisphere circulation. In a series of chemical transport model (GEOS-Chem) sensitivity experiments, we identify mechanisms that control the MSA concentrations recorded in ice cores. Sea ice is linked to MSA via dimethylsulfide (DMS), which is produced biologically in the surface ocean and known to be particularly concentrated in the sea ice zone. Given existing ocean surface DMS concentration data sets, the model does not demonstrate a strong relationship between sea ice and MSA deposition in Antarctica. The variability of DMS emissions associated with sea ice extent is small (1130%) due to the small interannual variability of sea ice extent. Wind plays a role in the variability in DMS emissions, but its contribution relative to that of sea ice is strongly dependent on the assumed DMS concentrations in the sea ice zone. Atmospheric sulfur emitted as DMS from the sea ice undergoes net transport northward. Our model runs suggest that DMS emissions from the sea ice zone may account for 2662% of MSA deposition at the Antarctic coast and 3695% in inland Antarctica. Though our results are sensitive to model assumptions, it is clear that an improved understanding of both DMS concentrations and emissions from the sea ice zone are required to better assess the impact of sea ice variability on MSA deposition to Antarctica.
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| Programme |
414 |
| Campaign |
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Thesis |
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Place of Publication |
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Series Issue |
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Edition |
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| ISSN |
2156-2202 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
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Approved |
yes |
| Call Number |
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Serial |
1119 |
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| Author |
Kukui A, Legrand M, Ancellet G, Gros V, Bekki S, Sarda-Estève R, Loisil R, Preunkert S, |
| Title |
Measurements of OH and RO2 radicals at the coastal Antarctic site of Dumont d'Urville (East Antarctica) in summer 20102011
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Type |
Journal Article |
| Year |
2012 |
Publication |
Journal of Geophysical Research: Atmospheres |
Abbreviated Journal |
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| Volume |
117 |
Issue |
D12 |
Pages |
D12310- |
| Keywords |
Antarctic photochemistry, Atmospheric oxidants, Hydroxyl radicals, 0322 Constituent sources and sinks, 0365 Troposphere: composition and chemistry, 0368 Troposphere: constituent transport and chemistry, |
| Abstract |
Measurements of OH and total peroxy RO2 (HO2 plus organic peroxy) radicals were conducted in December 2010/January 2011 at the coastal East Antarctic site of Dumont d'Urville (DDU, 66°40S 140°01E) as part of the Oxidant Production over Antarctic Land and its Export (OPALE) project. Compared to measurements carried out at the West Antarctic coast, relatively high concentrations of radicals were found with 24 h average values of 2.1 × 106 and 3.3 × 108 molecule cm3 for OH and peroxy radicals, respectively. On the basis of the steady state calculations, the observed high concentration of peroxy radicals is in good agreement with the observed levels of O3 and HCHO representing via their photolysis the major primary radical sources. The observed OH levels at DDU could be explained only assuming some RO2 to OH conversion mechanism equivalent to the presence of NO in the range of 10 to 50 pptv. As neither NO nor halogen oxides were measured at DDU the mechanism of this recycling could not be explicitly identified. However, an examination of variability of radical levels as a function of the origin (oceanic versus continental) of sampled air masses suggests a more important OH production from RO2 recycling in continental air masses.
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| Programme |
414 |
| Campaign |
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Thesis |
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Place of Publication |
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Summary Language |
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Series Title |
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| ISSN |
2156-2202 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
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Approved |
yes |
| Call Number |
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Serial |
3816 |
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| Author |
Kerbrat Michael, Legrand Michel, Preunkert Susanne, Gallée Hubert, Kleffmann Jörg, |
| Title |
Nitrous acid at Concordia (inland site) and Dumont d'Urville (coastal site), East Antarctica
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Type |
Journal Article |
| Year |
2012 |
Publication |
Journal of Geophysical Research: Atmospheres |
Abbreviated Journal |
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| Volume |
117 |
Issue |
D8 |
Pages |
D08303- |
| Keywords |
East Antarctica, LOPAP, nitrous acid, 0322 Constituent sources and sinks, 0365 Troposphere: composition and chemistry, 0368 Troposphere: constituent transport and chemistry, |
| Abstract |
During the austral summer 2010/2011, nitrous acid (HONO) was investigated for the first time at Concordia (75°06S, 123°33E) and Dumont D'Urville (66°40S, 140°01E), two sites located in East Antarctica. Hereby, for the first time in Antarctica, HONO was measured by deploying a long path absorption photometer (LOPAP). At Concordia, HONO mixing ratios at 1 m above the snow surface ranged between 5 and 60 pptv from end of December 2010 to mid January 2011. Lowest levels were observed under cloudy conditions. Levels exhibit a diurnal cycle with a maximum in the morning (around 06:00) and in the evening (around 21:00). At Dumont d'Urville, background mixing ratios remained close to 2 pptv in February 2011. No clear diurnal cycles were detected at that site but several events of air masses export from inland Antarctica were encountered with enhanced HONO levels (10 pptv) at night. These first HONO data gained in East Antarctica are discussed in terms of sources and sinks along with synoptic weather conditions.
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| Programme |
414;903 |
| Campaign |
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| Address |
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| Corporate Author |
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Thesis |
Bachelor's thesis |
| Publisher |
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Place of Publication |
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Editor |
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| Language |
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Summary Language |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
2156-2202 |
ISBN |
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Expedition |
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| Notes |
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Approved |
yes |
| Call Number |
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Serial |
3817 |
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| Author |
Preunkert Susanne, Ancellet Gérard, Legrand Michel, Kukui Alexandre, Kerbrat Michael, Sarda-Estève Roland, Gros Valérie, Jourdain Bruno, |
| Title |
Oxidant Production over Antarctic Land and its Export (OPALE) project: An overview of the 20102011 summer campaign
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Type |
Journal Article |
| Year |
2012 |
Publication |
Journal of Geophysical Research: Atmospheres |
Abbreviated Journal |
|
| Volume |
117 |
Issue |
D15 |
Pages |
D15307- |
| Keywords |
Antarctic photochemistry, atmospheric oxidants, hydroxyl radicals, nitrous acid, 0315 Biosphere/atmosphere interactions, 0365 Troposphere: composition and chemistry, 0368 Troposphere: constituent transport and chemistry, |
| Abstract |
This paper summarizes the objectives and setting of the OPALE (Oxidant Production over Antarctic Land and its Export) project during summer 2010/2011 at Dumont d'Urville. The primary goal of the campaign is to characterize the oxidizing environment of the atmospheric boundary layer along the coast of East Antarctica. A summary of the relevant field chemical measurements is presented including the carbon monoxide and ammonia records that are used here to identify local influences due to station activities and penguin emissions. An overview of the basic meteorological conditions experienced by the site is presented including the results from the trajectory/dispersion model FLEXPART to highlight which types of air mass were sampled (marine boundary layer versus continental Antarctic air). The results of the FLEXPART analysis demonstrate that high ozone levels and related changes in the OH concentrations are associated with the transport of continental air to DDU. Finally, three companion papers are introduced. A first paper is dedicated to the impact of local penguin emissions on the atmospheric budget of several oxygenated volatile organic compounds. The second paper reports on HONO levels that were measured for the first time in Antarctica by using the long path absorption photometer (LOPAP) technique. Finally, in a third paper, major findings on the HOx levels are detailed, leading to the overall conclusion that the photochemistry at coastal East Antarctica is strongly driven by an efficient HOx chemistry compared to the situation at other coastal Antarctic regions.
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| Programme |
414 |
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Place of Publication |
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Summary Language |
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Original Title |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
2156-2202 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
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Approved |
yes |
| Call Number |
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Serial |
3822 |
| Permanent link to this record |
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| Author |
Ardhuin Fabrice, Balanche Abel, Stutzmann E, Obrebski Mathias, |
| Title |
From seismic noise to ocean wave parameters: General methods and validation
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Type |
Journal Article |
| Year |
2012 |
Publication |
Journal of Geophysical Research: Oceans |
Abbreviated Journal |
|
| Volume |
117 |
Issue |
C5 |
Pages |
C05002- |
| Keywords |
directional spectrum, microseisms, ocean waves, 4546 Nearshore processes, 4560 Surface waves and tides, 4594 Instruments and techniques, 7219 Seismic monitoring and test-ban treaty verification, 7255 Surface waves and free oscillations, |
| Abstract |
Seismic noise is an indirect source of information on ocean waves. Using a model of noise generation and propagation, seismic stations can be separated into those that are mostly sensitive to local sea states, and those that integrate sources from a large oceanic area. The model also provides a classification of noise-generating sea states into three classes. The analysis of Central California seismic noise data, well correlated with local waves, reveals that class I events dominate in summer, caused by a single wind-sea system, and for which ocean wave spectral levels are proportional to seismic spectral levels to an exponentb 0.9. In winter, noise is dominated by class II generation, for which coastal reflection is important, with a wave spectral density roughly proportional to the seismic spectral density to an exponent b 0.7. Sporadic events of class III probably produce some of the strongest noise events in Central California and need to be properly screened. These events are caused by opposed wave systems that are usually the wind-sea and a swell. This noise classification can be used to improve on the correlation between measured and estimated wave heights (up tor = 0.93 for daily averages). For other locations, where remote oceanic sources are recorded, a significant wave height estimated from the seismic noise compares well with area-averaged satellite data or wave model results (r > 0.85 for daily averages). These analyses pave the way for quantitative uses of seismic records, including the reconstruction of past wave climates, and the calibration of wave hindcasts.
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| Programme |
133 |
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Place of Publication |
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Summary Language |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
2156-2202 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
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Approved |
yes |
| Call Number |
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Serial |
3832 |
| Permanent link to this record |
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| Author |
Ohtaki Toshiki, Kaneshima Satoshi, Kanjo Kenji, |
| Title |
Seismic structure near the inner core boundary in the south polar region
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Type |
Journal Article |
| Year |
2012 |
Publication |
Journal of Geophysical Research: Solid Earth |
Abbreviated Journal |
J. Geophys. Res. |
| Volume |
117 |
Issue |
B3 |
Pages |
B03312- |
| Keywords |
P-wave velocity and attenuation, inner and outer core, south polar region, 1507 Core processes, 7203 Body waves, 7207 Core, 8115 Core processes, 8124 Earth's interior: composition and state, |
| Abstract |
It is crucial to obtain good spatial coverage of seismic data points for better understanding the Earth's core, but the core beneath the polar regions remains largely unexplored. We analyzed differential traveltimes and amplitude ratios of core phases whose raypaths run beneath Antarctica for determining the Vp and Qp structure near the inner core boundary in the south polar region. The model we obtained (south polar region model, SPR) is described relative to the preliminary reference Earth model (PREM) as follows: a 0.05 km/s lower Vp value at the top of the inner core, a 1.5 times steeper Vp gradient in the upper 300 km of the inner core, a smaller Qp (300) in the upper 300 km of the inner core, and a 0.04 km/s lower Vp at the bottom of the outer core. The Vp values of SPR in the lowermost outer core lie between those of PREM and AK135, being closer to those of AK135. The lowermost outer core Vp inside the tangent cylinder is thus close to the global average. In the upper inner core, SPR has lower Vp than AK135 and PREM. The SPR Vp profile is close to that of previous models for the Western Hemisphere, although most of our data sample the Eastern Hemisphere of the inner core. Our results indicate that the inner core does not have a simple hemispherical variation as usually supposed. Our data support an eyeball-shaped high-Vp anomaly with compressional velocity higher than in 1-D reference Earth models, concentrated to a smaller region beneath eastern Asia.
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133 |
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Place of Publication |
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Summary Language |
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Original Title |
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Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
2156-2202 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
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Approved |
yes |
| Call Number |
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Serial |
3833 |
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| Author |
Legrand Michel, Gros Valérie, Preunkert Susanne, Sarda-Estève Roland, Thierry Anne-Mathilde, Pépy Guillaume, Jourdain B, |
| Title |
A reassessment of the budget of formic and acetic acids in the boundary layer at Dumont d'Urville (coastal Antarctica): The role of penguin emissions on the budget of several oxygenated volatile organic compounds
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Type |
Journal Article |
| Year |
2012 |
Publication |
Journal of Geophysical Research: Atmospheres |
Abbreviated Journal |
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| Volume |
117 |
Issue |
D6 |
Pages |
D06308- |
| Keywords |
carboxylic acids, formic and acetic acids, ornithogenic soil emission, oxygenated volatile compounds, 0315 Biosphere/atmosphere interactions, 0330 Geochemical cycles, 0365 Troposphere: composition and chemistry, |
| Abstract |
Initiated in 1997, the year-round study of formic and acetic acids was maintained until 2011 at the coastal Antarctic site of Dumont d'Urville. The records show that formic and acetic acids are rather abundant in summer with typical mixing ratios of 200 pptv and 700 pptv, respectively. With the aim to constrain their budget, investigations of their potential marine precursors like short-chain alkenes and acetaldehyde were initiated in 2011. Acetic acid levels in December 2010 were four times higher than those observed over summers back to 1997. These unusually high levels were accompanied by unusually high levels of ammonia, and by an enrichment of oxalate in aerosols. These observations suggest that the guano decomposition in the large penguin colonies present at the site was particularly strong under weather conditions encountered in spring 2010 (important snow storms followed by sunny days with mild temperatures). Although being dependent on environmental conditions, this process greatly impacts the local atmospheric budget of acetic acid, acetaldehyde, and acetone during the entire summer season. Present at levels as high as 500 pptv, acetaldehyde may represent the major precursor of acetic acid, alkene-ozone reactions remaining insignificant sources. Far less influenced by penguin emissions, the budget of formic acid remains not fully understood even if alkene-ozone reactions contribute significantly.
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| Programme |
414;903 |
| Campaign |
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| Address |
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| Corporate Author |
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Thesis |
Bachelor's thesis |
| Publisher |
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Place of Publication |
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Editor |
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| Language |
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Summary Language |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
2156-2202 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
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Approved |
yes |
| Call Number |
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Serial |
3995 |
| Permanent link to this record |
