Mapping the sedimentary basins of the Barents and Kara Seas using ERS-1 altimetry-geodetic mission     

Géli  Louis  Blanc  Frédérique 《Marine Geophysical Researches》1998,20(2):109-127

The continental shelf in the Arctic north of Russia consists of a series of epicontinental seas, which are the offshore continuation of potentially oil and gas basins on land. The geology of all these epicontinental seas is poorly known, due to the remoteness, the extreme climatic conditions and the extensive costs associated with seismic exploration. Radar altimeter sensors thus provide an invaluable tool for studying the geological structures off the coast. The unique ERS-1 contribution comes from its high latitude coverage (81.5 deg south to north), and the space and time density of its measurements (168-day repeat-orbit).The gravity anomaly field is derived from the geoid height measurements by computing the deflections of the vertical in the north-south and east-west directions and transforming these deflections into gravity anomalies. The gravimetry reveals interesting features of the basement of the Barents and Kara Seas which have not been chartered in recent, previous compilation maps of sedimentary thickness in the Arctic Ocean (Jackson and Oakey, 1988; Gramberg and Puscharovski, 1989). We obtain no indication of the SE-NW offshore Baikalian trend described by Fichler et al (1997) using ERS-1 gravimetry. Instead, the data indicate the presence of a north-south trending gravity high associated with the maximum sediment thickness within the South Barents Sea and the North Barents Sea Basins. Further geological studies are needed to interpret the gravimetric data, which directly addresses the problem of understanding the gravity signature of deep, old, sedimentary basins.  相似文献   

Formation temperatures of clays from the volcaniclastic series of Site 841 ODP: an oxygen isotopic record of a paleothermal flux into the Tonga forearc     

Frédéric Vitali  Gérard Blanc  François Gauthier-Lafaye  Christian France-Lanord 《Contributions to Mineralogy and Petrology》1999,134(4):364-369

Oxygen isotopic compositions of clay minerals were determined on representative samples of the volcano-sedimentary series from Site 841 ODP (Tonga forearc). This isotopic study has demonstrated an abnormally high crystallisation temperature of the clay minerals with respect to temperature expected in burial diagenesis. Formation temperatures obtained using ¹⁸O reach up to 200 °C in a Fe-chlorite-corrensite paragenesis found in the vicinity of basaltic andesite sills intruded into the Miocene tuffs. The paleothermal flux resulting from the cooling of the sills has produced very low grade contact metamorphism in the Miocene Tonga forearc deposits. The consequence of this was the formation of a large amount of hydrous silicates characterised near the sills by a Fe-clays-analcime mineralogical association. Received: 26 September 1997 / Accepted: 22 September 1998  相似文献   

Visible and near-infrared spectrophotometry of the Deep Impact ejecta of Comet 9P/Tempel 1     

Klaus W. Hodapp  Greg Aldering  Anita L. Cochran  Emmanuel Pécontal  Nathalie Blanc  David K. Lynch  S. Mazuk  Richard C. Puetter 《Icarus》2007,187(1):185-198

We have obtained optical spectrophotometry of the evolution of Comet 9P/Tempel 1 after the impact of the Deep Impact probe, using the Supernova Integral Field Spectrograph (SNIFS) at the UH 2.2-m telescope, as well as simultaneous optical and infrared spectra using the Lick Visible-to-Near-Infrared Imaging Spectrograph (VNIRIS). The spatial distribution and temporal evolution of the “violet band” CN (0-0) emission and of the 630 nm [OI] emission was studied. We found that CN emission centered on the nucleus increased in the 2 h after impact, but that this CN emission was delayed compared to the light curve of dust-scattered sunlight. The CN emission also expanded faster than the cloud of scattering dust. The emission of [OI] at 630 nm rose similarly to the scattered light, but then remained nearly constant for several hours after impact. On the day following the impact, both CN and [OI] emission concentrated on the comet nucleus had returned nearly to pre-impact levels. We have also searched for differences in the scattering properties of the dust ejected by the impact compared to the dust released under normal conditions. Compared to the pre-impact state of the comet, we find evidence that the color of the comet was slightly bluer during the post-impact rise in brightness. Long after the impact, in the following nights, the comet colors returned to their pre-impact values. This can be explained by postulating a change to a smaller particle size distribution in the ejecta cloud, in agreement with the findings from mid-infrared observations, or by postulating a large fraction of clean ice particles, or by a combination of these two.  相似文献   

Length of phytoplankton species patches on the Southern California Shelf     

Richard W. Eppley  Freda M.H. Reid  Elisabeth Stewart 《Continental Shelf Research》1984,3(3):259-266

Study of a longshore transect off Southern California suggests that the length scales (22 to 27 km) of phytoplankton species patches may be related to those of low-frequency currents. The patch boundaries were independent of shelf width but they were probably not independent of changes in chlorophyll fluorescence, temperature, and bottom topography.  相似文献   

Preliminary Archaeomagnetic Results from a Floor Sequence of a Bread Kiln in Lübeck (Germany)     

Schnepp  Elisabeth  Pucher  Rudolf 《Studia Geophysica et Geodaetica》1998,42(1):1-11

A sequence of 25 bread-kiln floors was sampled for archaeomagnetic measurements in a bakehouse in the old town of Lübeck, Germany. Due to archaeological dating this kiln floor sequence has been built up presumably from the late 13 ^th to the 18 ^th century. The primary magnetisation component is carried by magnetite (maghemite) and is very stable. Small viscous magnetisation components could be removed easily. The preliminary results of characteristic remanent magnetisation for 23 of the kiln-floor layers show clearly the trend of the geomagnetic secular variation expected for that time interval. By comparison with French and British master curves, the kiln-floor sequence started around 1425 and lasted until 1775 AD. Presently, confidence circles are relatively large and need refineing by measuring more samples, which have already been collected. Together with ¹⁴ C dating that can be determined from the charcoals found in the lowest layers and thermoluminescence dating of the layers, we expect to obtain, for the first time, a secular variation curve for Northern Germany covering the time interval from 1400 to 1800 years AD.  相似文献   

The phthalate diesters DEHP and DBP do not induce lauric acid hydroxylase activity in rainbow trout   总被引：1，自引：0，他引：1  

Cravedi JP  Perdu-Durand E 《Marine environmental research》2002,54(3-5):787-791

Aquatic organisms are extensively exposed to phthalate esters. We have investigated in trout the effects of diethylhexylphthalate (DEHP) and dibutylphthalate (DBP) on xenobiotic metabolizing enzymes which have been suggested as possible environmental biomarkers. Rainbow trout (Oncorhynchus mykiss) were waterborne exposed to DEHP (1 mg/l) or DBP (0.1 or 1 mg/l) for 72 h. Another group of rainbow trout received daily for 3 days an intraperitoneal injection of 50 mg/kg of DEHP or DBP. Laurate hydroxylation, ethoxyresorufin-o-deethylation, UDP-glucuronyltransferase activity and glutathione-S-transferase activity were measured in liver and extrahepatic tissues. The phthalate esters have been found not to induce these enzymes; in particular, the results do not support the previously described induction of lauric acid hydroxylase in sea bass treated with DEHP [Comp. Biochem. Physiol. B122 (1999) 253.].  相似文献   

A qualitative Natech damage scale for the impact of floods on selected industrial facilities   总被引：4，自引：2，他引：2  

Elisabeth Krausmann  Fesil Mushtaq 《Natural Hazards》2008,46(2):179-197

There is increasing evidence that natural disasters can trigger technological accidents and damage. These so-called Natech accidents can pose a significant risk to regions that are unprepared for responding to them. The European Commission’s Joint Research Centre has recognised the risk associated with Natech events and has started systematic research into Natechs and their underlying dynamics. This work investigates the risk associated with the flooding of industrial installations through an analysis of past case histories and using expert judgement. The potential impact of three levels of flood severity on selected industrial facilities storing and/or processing (eco-)toxic, flammable or explosive materials is analysed qualitatively and a scale is developed that links the flood intensity to the level of potential damage. Our analysis indicates that natural disasters have the potential for triggering hazmat releases and other types of technological accidents. Hence, natural disasters should be considered as separate accident-triggering events in the planning, design and operating stages of industrial facilities that process or store hazardous substances. Our work revealed a lack of detailed information on the occurrence of Natech events which indicates not necessarily a scarcity of Natechs but rather a lack of standardised reporting and record keeping.  相似文献   

The 3410 Å band of the PH molecule in the solar photospheric spectrum     

Elisabeth M. De Gouveia  P. D. Singh 《Solar physics》1984,90(2):259-268

Some weak unidentified solar photospheric lines in the wavelength range: (3400–3465) Å may be due to PH lines of the (0, 0) band of the PH(A ³ _i - X ^{3 -})system. These faint PH molecular lines have resulted an excitation temperature of the order of 4500 K. Using experimental lifetime data for PH in the A ³ _i state, an absorption oscillator strength f ₀₀ = 0.0075 is derived for the 3410 Å band of the PH (A ³ _i - X ^{3 -})system. Accurate line positions, oscillator strength and transition probability for the 4.4 fundamental rotation-vibration band of the PH molecule are obtained. A comparison of positions of some lines of the 4.4 band with those obtained on new tracings of high resolution solar spectra shows many coincidences with weak solar lines.  相似文献   

Citizens' perceptions of justice in international climate policy: an empirical analysis     

Joachim Schleich  Elisabeth Dütschke  Claudia Schwirplies  Andreas Ziegler 《Climate Policy》2016,16(1):50-67

Relying on a recent survey of more than 3400 participants from China, Germany, and the US, this article empirically analyses citizens' perceptions of key guiding principles for sharing mitigation costs across countries, justification of climate policy and trust in climate policy. Our findings suggest that the ranking of the main principles for burden-sharing is identical in China, Germany, and the US: accountability followed by capability, egalitarianism, and sovereignty. Thus, on a general level, citizens across these countries seem to have a common (normative) understanding of fairness. We therefore find no evidence that citizens' (stated) fairness preferences are detrimental to future burden-sharing agreements. In all three countries a majority of citizens considers international climate policy to be justified, but citizens' perceptions differ across specific items and countries. Finally, a substantial portion of citizens in all countries exhibit a lack of trust in international climate agreements.

Policy relevance

Disagreement over the distribution of mitigation costs across countries is blocking current negotiations about a new international climate change agreement to be adopted in 2015. At the heart of this disagreement are different perceptions of distributive justice among those involved in climate policy making. Our findings show that there is no difference in the ranking of fairness principles across citizens in China, Germany, and the US, suggesting that the common ground for crafting a future agreement is larger than expected. In particular, the accountability principle should weigh heavily when deciding on the burden-sharing. In addition, our findings suggest that in order to gain support among citizens, international climate policy may need to take measures to improve trust.  相似文献   

Reducing climate risk for micro-insurance providers in Africa: A case study of Ethiopia     

Elisabeth Meze-Hausken  Anthony Patt  Steffen Fritz 《Global Environmental Change》2009,19(1):66-73

Recurrent climate hazards challenge subsistence farmers in developing countries. Reliance on various diversification strategies and traditional risk sharing among kin and families has serious limitations, such as the problem of covariate risk within such networks. Index-based crop insurance could help to reduce people's climate-related risk, but raising the necessary capital to make insurance schemes financially secure is difficult for micro-insurance providers. We examine the extent to which spatial pooling of micro-insurance schemes could reduce these capital requirements. We simulate a hypothetical insurance market operating in Ethiopia, using rainfall data and yield estimates for 15 stations. By performing a Monte Carlo analysis, risk capital required to keep the probability of financial ruin below a threshold value is identified. We investigate the marginal benefits of pooling increasing numbers of sites, as well as the relationship between the benefits of pooling and the spatial covariance of rainfall. We find spatial diversification to offer considerable savings in required capitalization with as few as three sites pooled, as well as a weak but significant relationship between rainfall covariance and those benefits. The results suggest that spatial pooling may be an attractive option for micro-insurers, worthy of a detailed case-by-case analysis when designing index-insurance schemes.  相似文献