scholarly journals Small shards and long distances – three cryptotephra layers from the Nahe palaeolake including the first discovery of Laacher See Tephra in Schleswig-Holstein (Germany)

2020 ◽  
Author(s):  
Sascha Krüger ◽  
Christel van den Bogaard
Keyword(s):  
High Resolution ◽  
Lake Sediments ◽  
Temporal Resolution ◽  
Early Holocene ◽  
Northern Germany ◽  
North West ◽  
Pollen Stratigraphy ◽  
The North ◽  
Laacher See Tephra

Investigations of Lateglacial to Early Holocene lake sediments from the Nahe palaeolake (northern Germany) provided a high-resolution palynological record. To increase the temporal resolution of the record a targeted search for cryptotephra was carried out on the basis of pollen stratigraphy. Three cryptotephra horizons were detected and geochemically identified as Saksunarvatn Ash, Vedde Ash and Laacher See Tephra. Here we present the first geochemically confirmed finding of the ash from the Laacher See Eruption in Schleswig-Holstein – extending the so far detected fallout fan of the Lateglacial eruption further to the North-West. These finds enable direct stratigraphical correlations and underline the potential of the site for further investigations.

Seismic structure of the Cheb Basin from high resolution surveying – data quality assessment and first results

2021 ◽  
Author(s):  
Natalia Banasiak ◽  
Florian Bleibinhaus
Keyword(s):  
High Resolution ◽  
Earthquake Activity ◽  
Seismic Structure ◽  
North West ◽  
The North ◽  
Eger Rift ◽  
First Results ◽  
Ground Roll ◽  
Variscan Granites ◽  
Cheb Basin

<p><span><span>In this study we present data and preliminary results from several shallow high-resolution seismic surveys in the Cheb Basin, CR, a small intracontinental basin in the North-West Bohemian Massif, located at the Western end of the Cenozoic Eger Rift. The area is well known for its intense earthquake activity, with the largest instrumentally recorded magnitude of M</span></span><span><sub><span>L</span></sub></span><span><span>=4.6. Macroseismic reports of local seismicity date back to the early 19</span></span><span><sup><span>th</span></sup></span><span><span> century, with magnitudes possibly above 5. Quaternary volcanoes, CO</span></span><span><sub><span>2</span></sub></span><span><span>-rich moffettes, and the swarm-like occurrence of the earthquakes suggest they are being triggered by crustal fluids. In contrast, most focal mechanisms show a dominant strike-slip component, indicative of tectonics. Investigating the role of fluids in triggering those earthquakes is one of the objectives of an ongoing ICDP program.</span></span></p><p><span>We expect high-resolution images of the basin structure to provide additional constraints regarding the importance of tectonic faulting. To that end, we surveyed several up to 3-km-long reflection and refraction profiles in the basin center across the putative Počátky-Plesná Fault, and at its edge, across the basin-bounding Mariánské Lázně Fault. The up to 350-m-thick basin sediments are mostly of Miocene and Quaternary origin, overlying Paleozoic Variscan units and post-Variscan granites. The main reflectors are around 200-400 ms. The data were collected with a 500-m-long split-spread of single geophones at 2 m spacing, and the raw shots are dominated by ground roll. In this presentation, we will show an overview of the field campaigns and present first results.</span></p>

DEMETER HIGH RESOLUTION 3D SEISMIC SURVEY—REVITALISED DEVELOPMENT AND EXPLORATION ON THE NORTH WEST SHELF, AUSTRALIA

2006 ◽  
Vol 46 (1) ◽  
pp. 101 ◽  
Author(s):  
K.J. Bennett ◽  
M.R. Bussell
Keyword(s):  
High Resolution ◽  
Seismic Data ◽  
New Technologies ◽  
Seismic Survey ◽  
Future Application ◽  
3D Seismic ◽  
Gas Field ◽  
North West ◽  
The North ◽  
Exploration And Development

The newly acquired 3,590 km2 Demeter 3D high resolution seismic survey covers most of the North West Shelf Venture (NWSV) area; a prolific hydrocarbon province with ultimate recoverable reserves of greater than 30 Tcf gas and 1.5 billion bbls of oil and natural gas liquids. The exploration and development of this area has evolved in parallel with the advent of new technologies, maturing into the present phase of revitalised development and exploration based on the Demeter 3D.The NWSV is entering a period of growing gas market demand and infrastructure expansion, combined with a more diverse and mature supply portfolio of offshore fields. A sequence of satellite fields will require optimised development over the next 5–10 years, with a large number of wells to be drilled.The NWSV area is acknowledged to be a complex seismic environment that, until recently, was imaged by a patchwork of eight vintage (1981–98) 3D seismic surveys, each acquired with different parameters. With most of the clearly defined structural highs drilled, exploration success in recent years has been modest. This is due primarily to severe seismic multiple contamination masking the more subtle and deeper exploration prospects. The poor quality and low resolution of vintage seismic data has also impeded reservoir characterisation and sub-surface modelling. These sub-surface uncertainties, together with the large planned expenditure associated with forthcoming development, justified the need for the Demeter leading edge 3D seismic acquisition and processing techniques to underpin field development planning and reserves evaluations.The objective of the Demeter 3D survey was to re-image the NWSV area with a single acquisition and processing sequence to reduce multiple contamination and improve imaging of intra-reservoir architecture. Single source (133 nominal fold), shallow solid streamer acquisition combined with five stages of demultiple and detailed velocity analysis are considered key components of Demeter.The final Demeter volumes were delivered early 2005 and already some benefits of the higher resolution data have been realised, exemplified in the following:Successful drilling of development wells on the Wanaea, Lambert and Hermes oil fields and identification of further opportunities on Wanaea-Cossack and Lambert- Hermes;Dramatic improvements in seismic data quality observed at the giant Perseus gas field helping define seven development well locations;Considerably improved definition of fluvial channel architecture in the south of the Goodwyn gas field allowing for improved well placement and understanding of reservoir distribution;Identification of new exploration prospects and reevaluation of the existing prospect portfolio. Although the Demeter data set has given significant bandwidth needed for this revitalised phase of exploration and development, there remain areas that still suffer from poor seismic imaging, providing challenges for the future application of new technologies.

Evaluation of trends in extreme temperatures simulated by HighResMIP models across Europe

2020 ◽  
Author(s):  
Gerard van der Schrier ◽  
Antonello Squintu ◽  
Else van den Besselaar ◽  
Eveline van der Linden ◽  
Enrico Scoccimarro ◽  
...  
Keyword(s):  
High Resolution ◽  
Western Europe ◽  
Extreme Values ◽  
Maximum Temperature ◽  
Western Balkans ◽  
North West ◽  
The Balkans ◽  
The North ◽  
Summer Maximum ◽  
Maximum Temperatures

<p>The comparison of simulated climate with observed daily values allows to assess their reliability and the soundness of their projections on the climate of the future. Frequency and amplitude of extreme events are fundamental aspects that climate simulations need to reproduce. In this work six models developed within the High Resolution Model Intercomparison Project are compared over Europe with the homogenized version of the observational E-OBS gridded dataset. This is done by comparing averages, extremes and trends of the simulated summer maximum temperature and winter minimum temperatures with the observed ones.</p><p>Extreme values have been analyzed making use of indices based on the exceedances of percentile-based thresholds. Winter minimum temperatures are generally underestimated by models in their averages (down to -4 deg. C of difference over Italy and Norway) while simulated trends in averages and extreme values are found to be too warm on western Europe and too cold on eastern Europe (e.g. up to a difference of -4% per decade on the number of Cold Nights over Spain). On the other hand the models tend to underestimate summer maximum temperatures averages in Northern Europe and overestimate them in the Mediterranean areas (up to +5 deg. C over the Balkans). The simulated trends are too warm on the North West part and too cold on the South East part of Europe (down to -3%/dec. on the number of Warm Days over Italy and Western Balkans).</p><p>These results corroborate the findings of previous studies about the underestimation of the warming trends of summer temperatures in Southern Europe, where these are more intense and have more impacts.  A comparison of the high resolution models  with the corresponding version in CMIP5 has been performed comparing the absolute biases of extreme values trends. This has shown a slight improvement for the simulation of winter minimum temperatures, while no signs of significant progresses have been found for summer maximum temperatures.</p>

scholarly journals The Stone Vessels in the Cities of Russian North-West

2018 ◽  
pp. 361-371
Author(s):  
П. Е. Сорокин ◽  
В. И. Кильдюшевский ◽  
В. Н. Матвеев
Keyword(s):  
Middle Ages ◽  
Baltic Region ◽  
Northern Germany ◽  
North West ◽  
Political Processes ◽  
Baltic Countries ◽  
The North ◽  
Late Middle Ages ◽  
Russian North ◽  
The Baltic

Сосуды из каменной массы, изготавливавшиеся в городах Северной Германии и получившие в литературе название рейнской керамики, были широко распространены в позднее Средневековье и Новое время в Северной Европе. В русских городах они встречаются значительно реже, причем в основном на Северо-Западе, вовлеченном в балтийскую торговлю. Значительно более широко они представлены в Восточной Прибалтике, Финляндии, а также в городах Выборг, Ниеншанц и Но-тебург, входивших в состав шведских владений. Поступление сосудов из каменной массы в прибалтийские страны отражает торговые и политические процессы в Балтийском регионе. The stone vessels, manufactured in the cities of Northern Germany and got the name of Rhenish ceramics in literature were widespread in the Late Middle Ages and Modern Time in Northern Europe. In Russian cities, they are met much rarer, mostly in the North-West involved in the Baltic trade. Much more commonly they are represented in the Eastern Baltic countries, Finland, and also in the cities of Vyborg, Nyenschantz and Noteburg, which once were part of the Swedish realm. The flow of stone vessels into the Baltic countries reflects trade and political processes in the Baltic region.

scholarly journals AMM15: a new high-resolution NEMO configuration for operational simulation of the European north-west shelf

2018 ◽  
Vol 11 (2) ◽  
pp. 681-696 ◽  
Author(s):  
Jennifer A. Graham ◽  
Enda O'Dea ◽  
Jason Holt ◽  
Jeff Polton ◽  
Helene T. Hewitt ◽  
...  
Keyword(s):  
High Resolution ◽  
Horizontal Resolution ◽  
Bias Reduction ◽  
Small Scale ◽  
Operational System ◽  
North West ◽  
The North ◽  
European North ◽  
The Mean ◽  
Mean State

Abstract. This paper describes the next-generation ocean forecast model for the European north-west shelf, which will become the basis of operational forecasts in 2018. This new system will provide a step change in resolution and therefore our ability to represent small-scale processes. The new model has a resolution of 1.5 km compared with a grid spacing of 7 km in the current operational system. AMM15 (Atlantic Margin Model, 1.5 km) is introduced as a new regional configuration of NEMO v3.6. Here we describe the technical details behind this configuration, with modifications appropriate for the new high-resolution domain. Results from a 30-year non-assimilative run using the AMM15 domain demonstrate the ability of this model to represent the mean state and variability of the region.Overall, there is an improvement in the representation of the mean state across the region, suggesting similar improvements may be seen in the future operational system. However, the reduction in seasonal bias is greater off-shelf than on-shelf. In the North Sea, biases are largely unchanged. Since there has been no change to the vertical resolution or parameterization schemes, performance improvements are not expected in regions where stratification is dominated by vertical processes rather than advection. This highlights the fact that increased horizontal resolution will not lead to domain-wide improvements. Further work is needed to target bias reduction across the north-west shelf region.

scholarly journals AMM15: A new high resolution NEMO configuration for operational simulation of the European North West Shelf

2017 ◽  
Author(s):  
Jennifer A. Graham ◽  
Enda O’Dea ◽  
Jason Holt ◽  
Jeff Polton ◽  
Helene T. Hewitt ◽  
...  
Keyword(s):  
High Resolution ◽  
Horizontal Resolution ◽  
Bias Reduction ◽  
Small Scale ◽  
Operational System ◽  
North West ◽  
The North ◽  
European North ◽  
The Mean ◽  
Mean State

Abstract. This paper describes the next generation ocean forecast model for the European North West Shelf, which will become the basis of operational forecasts in 2018. This new system will provide a step change in resolution, and therefore our ability to represent small scale processes. The new model has a resolution of 1.5 km, compared with a grid spacing of 7 km in the current operational system. AMM15 (Atlantic Margin Model, 1.5 km) is introduced as a new regional configuration of NEMO v3.6. Here we describe the technical details behind this configuration, with modifications appropriate for the new high resolution domain. Results from a 30 year non-assimilative run, using the AMM15 domain, demonstrate the ability of this model to represent the mean state and variability of the region. Overall, there is an improvement in the representation of the mean state across the region, suggesting similar improvements may be seen in the future operational system. However, the reduction in seasonal bias is greater off-shelf than on-shelf. In the North Sea, biases are largely unchanged. Since there has been no change to the vertical resolution or parameterisation schemes, performance improvements are not expected in regions where stratification is dominated by vertical processes, rather than advection. This highlights the fact that increased horizontal resolution will not lead to domain-wide improvements. Further work is needed to target bias reduction across the North West Shelf region.

scholarly journals Freshwater pearl mussels from northern Sweden serve as long-term, high-resolution stream water isotope recorders

2019 ◽  
Author(s):  
Bernd R. Schöne ◽  
Aliona E. Meret ◽  
Sven M. Baier ◽  
Jens Fiebig ◽  
Jan Esper ◽  
...  
Keyword(s):  
High Resolution ◽  
Carbon Isotope ◽  
Temporal Resolution ◽  
North Atlantic ◽  
Stream Water ◽  
Winter Precipitation ◽  
The Arctic ◽  
Isotope Signature ◽  
The North ◽  
The North Atlantic

Abstract. The stable isotope composition of lacustrine sediments is routinely used to infer Late Holocene changes in precipitation over Scandinavia and ultimately, atmospheric circulation dynamics in the North Atlantic realm. However, such archives provide only low temporal resolution (ca. 15 years) precluding the ability to identify changes on inter-annual and quasi-decadal time-scales. Here we present a new, high-resolution reconstruction using shells of freshwater pearl mussels, Margaritifera margaritifera, from three rivers in north Sweden. We present seasonally to annually resolved, calendar-aligned stable oxygen and carbon isotope data from ten specimens covering the time interval of 1819 to 1998. The studied bivalves formed their shells near equilibrium with the oxygen isotope signature of ambient water and thus reflected hydrological processes in the catchment as well as changes, albeit damped, of the isotope value of local atmospheric precipitation. Shell oxygen isotopes were correlated significantly with the North Atlantic Oscillation index (up to 56 % explained variability) suggesting that moisture from which winter precipitation formed originated predominantly in the North Atlantic during NAO+ years, but in the Arctic during NAO– years. The specific isotope signature of winter precipitation was damped in stream water and this effect was recorded by the shells. Shell stable carbon isotope values did not show consistent ontogenetic trends, but rather oscillated around an average that differed slightly among the studied rivers (ca. −12.00 to −13.00 ‰). Results of this study contribute to an improved understanding of climate dynamics in Scandinavia and the North Atlantic sector and can help to constrain ecological changes in riverine ecosystems. Moreover, long isotope records of precipitation and streamflow are pivotal for improving our understanding and modeling of hydrological, ecological, biogeochemical and atmospheric processes. Our new approach offers a much higher temporal resolution and superior dating control than existing archives.

scholarly journals An approach to the verification of high-resolution ocean models using spatial methods

Ocean Science ◽  
2020 ◽  
Vol 16 (4) ◽  
pp. 831-845
Author(s):  
Ric Crocker ◽  
Jan Maksymczuk ◽  
Marion Mittermaier ◽  
Marina Tonani ◽  
Christine Pequignet
Keyword(s):  
High Resolution ◽  
Model Performance ◽  
Evaluation Process ◽  
In Situ Observation ◽  
Single Observation ◽  
Verification Method ◽  
North West ◽  
The North ◽  
Resolution Model ◽  
Ocean Models

Abstract. The Met Office currently runs two operational ocean forecasting configurations for the North West European Shelf: an eddy-permitting model with a resolution of 7 km (AMM7) and an eddy-resolving model at 1.5 km (AMM15). Whilst qualitative assessments have demonstrated the benefits brought by the increased resolution of AMM15, particularly in the ability to resolve finer-scale features, it has been difficult to show this quantitatively, especially in forecast mode. Applications of typical assessment metrics such as the root mean square error have been inconclusive, as the high-resolution model tends to be penalised more severely, referred to as the double-penalty effect. This effect occurs in point-to-point comparisons whereby features correctly forecast but misplaced with respect to the observations are penalised twice: once for not occurring at the observed location, and secondly for occurring at the forecast location, where they have not been observed. An exploratory assessment of sea surface temperature (SST) has been made at in situ observation locations using a single-observation neighbourhood-forecast (SO-NF) spatial verification method known as the High-Resolution Assessment (HiRA) framework. The primary focus of the assessment was to capture important aspects of methodology to consider when applying the HiRA framework. Forecast grid points within neighbourhoods centred on the observing location are considered as pseudo ensemble members, so that typical ensemble and probabilistic forecast verification metrics such as the continuous ranked probability score (CRPS) can be utilised. It is found that through the application of HiRA it is possible to identify improvements in the higher-resolution model which were not apparent using typical grid-scale assessments. This work suggests that future comparative assessments of ocean models with different resolutions would benefit from using HiRA as part of the evaluation process, as it gives a more equitable and appropriate reflection of model performance at higher resolutions.

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