High-resolution facies analysis of a Lower Devonian deltaic marine-terrestrial transition (Nellenköpfchen Formation, Rheinisches Schiefergebirge, Germany): implications for small-scale fluctuations of coastal environments

2010 ◽  
Vol 256 (3) ◽  
pp. 317-334 ◽  
Author(s):  
Achim Wehrmann ◽  
Volker Wilde ◽  
Eberhard Schindler ◽  
Rainer Brocke ◽  
Stephan Schultka
Keyword(s):  
High Resolution ◽  
Lower Devonian ◽  
Facies Analysis ◽  
Rheinisches Schiefergebirge ◽  
Small Scale ◽  
Coastal Environments

Significance in the Integration of Facies Analysis, Stable Isotopes and Diagenetical Results for the High-Resolution Sequence Stratigraphy Characterization in the Shallow Platform of Shuaiba Formation, Lower Cretaceous, Abu Dhabi Onshore, UAE

2021 ◽  
Author(s):  
Kevin Michael Torres ◽  
Noura Al Madani ◽  
Rodrigo Rafael Gutierrez
Keyword(s):  
High Resolution ◽  
Direct Evidence ◽  
Facies Analysis ◽  
Carbonate Platform ◽  
Nutrient Supply ◽  
Abu Dhabi ◽  
Small Scale ◽  
Facies Association ◽  
Accommodation Space ◽  
Shallow Platform

Abstract The study presents the sequence stratigraphy of the carbonate platform focused in lower part of Shuaiba Formation, as well as the organization of the arrangement formed by the cyclical sedimentological evolution at high-resolution scale, through the facies analysis, diagenetical imprints and finally, significance of stable carbonate isotope results in the building up of carbonate platform in southeast Abu Dhabi. Interpreted stratigraphic surfaces from integration of depositional facies reviewed in all available cored data within studied area and stable carbon isotope results allowed that four small-scale regression-transgression depositional cycles can be discriminated which are stacked into a medium-scale sequence, that may record a 600 kyr Milankovitch signal. The small-scale sequences were correlated within the studied area using both conventional well logs and stable isotope records. Transgression hemicycles represent the increasing of accommodation space and can be identified in direct evidence, such as 25-40 ft. thickness of lithocodium/bacinella floatstones and skeletal peloidal packstones facies, association of facies interpreted within upper slope sub-environment. Likewise, in δ13C profiles, the rise/fall turnarounds of small-scale sequences are marked by negative δ13C peaks and associated with characteristics patterns: (1) proportion decrease of shallower sub-environments facies is interpreted as an rising relative sea-level and (2) decreasing δ13C trends interpreted to be related to decreasing nutrient supply. The medium/big pores of floatstones poorly connected in packstone matrix are expressed in the medium/high porosity with low permeabilities. In contrast, regressive hemicycles represent the reduction in accommodation space and can be characterized in direct evidence, such as the growing up of persistent 10-20 ft. thickness with thousands of meters of correlation of stromatoporoids and rudist facies, association of facies interpreted within shelf-margin complex sub-environment. In addition, the fall/rise turnarounds are marked by positive δ13C peaks, associated with the stromatoporoids/rudists mounds with characteristic patterns: (1) proportion increase of shallower sub-environments facies is interpreted as falling relative sea-level and increase in proximity and (2) increasing δ13C values interpreted to reflect increasing nutrient supply. Unusually very high permeability is attributed to the present of fractures and dissolution events that is enhanced where proportion of stromatoporoids facies are more pronounced. The described characterization resulted in the identification of genetic cycles that reproduce the sedimentological evolution, which are presented in small-scale sequences. In addition, the δ13C values enabled to understand the internal organization and the development of the carbonate building up in the Shuaiba shallow platform evolution. This study provides update and understanding on sedimentary facies, depositional pattern, and expands on previous published works, using new approach from semi-regional to local scales. Finally, results help to understand the laterally extensive water break-through thin intervals, which are directly related to the regressive hemicycles described previously.

scholarly journals Circum-nuclear molecular disks: Role in AGN fueling and feedback

2019 ◽  
Vol 15 (S359) ◽  
pp. 312-317
Author(s):  
Francoise Combes
Keyword(s):  
Black Hole ◽  
Angular Momentum ◽  
High Resolution ◽  
Large Scale ◽  
Active Galaxy ◽  
Small Scale ◽  
Massive Black Hole ◽  
Molecular Outflows ◽  
Molecular Outflow

AbstractGas fueling AGN (Active Galaxy Nuclei) is now traceable at high-resolution with ALMA (Atacama Large Millimeter Array) and NOEMA (NOrthern Extended Millimeter Array). Dynamical mechanisms are essential to exchange angular momentum and drive the gas to the super-massive black hole. While at 100pc scale, the gas is sometimes stalled in nuclear rings, recent observations reaching 10pc scale (50mas), may bring smoking gun evidence of fueling, within a randomly oriented nuclear gas disk. AGN feedback is also observed, in the form of narrow and collimated molecular outflows, which point towards the radio mode, or entrainment by a radio jet. Precession has been observed in a molecular outflow, indicating the precession of the radio jet. One of the best candidates for precession is the Bardeen-Petterson effect at small scale, which exerts a torque on the accreting material, and produces an extended disk warp. The misalignment between the inner and large-scale disk, enhances the coupling of the AGN feedback, since the jet sweeps a large part of the molecular disk.

scholarly journals High resolution observations of spectral width features associatedwith ULF wave signatures in artificial HF radar backscatter

2004 ◽  
Vol 22 (1) ◽  
pp. 169-182 ◽  
Author(s):  
D. M. Wright ◽  
T. K. Yeoman ◽  
L. J. Baddeley ◽  
J. A. Davies ◽  
R. S. Dhillon ◽  
...  
Keyword(s):  
High Resolution ◽  
Plasma Source ◽  
Spectral Width ◽  
Hf Radar ◽  
Mhd Waves ◽  
Small Scale ◽  
Ulf Waves ◽  
Source Population ◽  
Radar Backscatter ◽  
Field Lines

Abstract. The EISCAT high power heating facility at Tromsø, northern Norway, has been utilised to generate artificial radar backscatter in the fields of view of the CUTLASS HF radars. It has been demonstrated that this technique offers a means of making very accurate and high resolution observations of naturally occurring ULF waves. During such experiments, the usually narrow radar spectral widths associated with artificial irregularities increase at times when small scale-sized (high m-number) ULF waves are observed. Possible mechanisms by which these particle-driven high-m waves may modify the observed spectral widths have been investigated. The results are found to be consistent with Pc1 (ion-cyclotron) wave activity, causing aliasing of the radar spectra, in agreement with previous modelling work. The observations also support recent suggestions that Pc1 waves may be modulated by the action of longer period ULF standing waves, which are simultaneously detected on the magnetospheric field lines. Drifting ring current protons with energies of ∼ 10keV are indicated as a common plasma source population for both wave types. Key words. Magnetospheric physics (MHD waves and instabilities) – Space plasma physics (wave-particle interactions) – Ionosphere (active experiments)

scholarly journals Evaluation of UAV LiDAR for Mapping Coastal Environments

2019 ◽  
Vol 11 (24) ◽  
pp. 2893 ◽  
Author(s):  
Yi-Chun Lin ◽  
Yi-Ting Cheng ◽  
Tian Zhou ◽  
Radhika Ravi ◽  
Seyyed Hasheminasab ◽  
...  
Keyword(s):  
High Resolution ◽  
Lake Michigan ◽  
Point Clouds ◽  
Volume Loss ◽  
Coastal Environments ◽  
Average Volume ◽  
Survey Period ◽  
Shoreline Changes ◽  
Point Density ◽  
One Year

Unmanned Aerial Vehicle (UAV)-based remote sensing techniques have demonstrated great potential for monitoring rapid shoreline changes. With image-based approaches utilizing Structure from Motion (SfM), high-resolution Digital Surface Models (DSM), and orthophotos can be generated efficiently using UAV imagery. However, image-based mapping yields relatively poor results in low textured areas as compared to those from LiDAR. This study demonstrates the applicability of UAV LiDAR for mapping coastal environments. A custom-built UAV-based mobile mapping system is used to simultaneously collect LiDAR and imagery data. The quality of LiDAR, as well as image-based point clouds, are investigated and compared over different geomorphic environments in terms of their point density, relative and absolute accuracy, and area coverage. The results suggest that both UAV LiDAR and image-based techniques provide high-resolution and high-quality topographic data, and the point clouds generated by both techniques are compatible within a 5 to 10 cm range. UAV LiDAR has a clear advantage in terms of large and uniform ground coverage over different geomorphic environments, higher point density, and ability to penetrate through vegetation to capture points below the canopy. Furthermore, UAV LiDAR-based data acquisitions are assessed for their applicability in monitoring shoreline changes over two actively eroding sandy beaches along southern Lake Michigan, Dune Acres, and Beverly Shores, through repeated field surveys. The results indicate a considerable volume loss and ridge point retreat over an extended period of one year (May 2018 to May 2019) as well as a short storm-induced period of one month (November 2018 to December 2018). The foredune ridge recession ranges from 0 m to 9 m. The average volume loss at Dune Acres is 18.2 cubic meters per meter and 12.2 cubic meters per meter within the one-year period and storm-induced period, respectively, highlighting the importance of episodic events in coastline changes. The average volume loss at Beverly Shores is 2.8 cubic meters per meter and 2.6 cubic meters per meter within the survey period and storm-induced period, respectively.

High resolution observations of small-scale magnetic elements and interpretation

Solar Physics ◽  
1996 ◽  
Vol 164 (1-2) ◽  
pp. 303-310 ◽  
Author(s):  
F. Kneer ◽  
F. Stolpe
Keyword(s):  
High Resolution ◽  
Small Scale ◽  
Magnetic Elements

scholarly journals The definition of an atmospheric database for Aeolus

2011 ◽  
Vol 4 (1) ◽  
pp. 67-88 ◽  
Author(s):  
G. J. Marseille ◽  
K. Houchi ◽  
J. de Kloe ◽  
A. Stoffelen
Keyword(s):  
High Resolution ◽  
Meteorological Data ◽  
Sampling Strategy ◽  
Laser Wavelength ◽  
Geographic Region ◽  
Atmospheric Dynamics ◽  
Specific Humidity ◽  
Small Scale ◽  
Horizontal Line ◽  
Definition Of

Abstract. The definition of an atmospheric database is an important component of simulation studies in preparation of future earth observing remote sensing satellites. The Aeolus mission, formerly denoted Atmospheric Dynamics Mission (ADM) or ADM-Aeolus, is scheduled for launch end of 2013 and aims at measuring profiles of single horizontal line-of-sight (HLOS) wind components from the surface up to about 32 km with a global coverage. The vertical profile resolution is limited but may be changed during in-orbit operation. This provides the opportunity of a targeted sampling strategy, e.g., as a function of geographic region. Optimization of the vertical (and horizontal) sampling strategy requires a characterization of the atmosphere optical and dynamical properties, more in particular the distribution of atmospheric particles and their correlation with the atmospheric dynamics. The Aeolus atmospheric database combines meteorological data from the ECMWF model with atmosphere optical properties data from CALIPSO. An inverse algorithm to retrieve high-resolution particle backscatter from the CALIPSO level-1 attenuated backscatter product is presented. Global weather models tend to underestimate atmospheric wind variability. A procedure is described to ensure compatibility of the characteristics of the database winds with those from high-resolution radiosondes. The result is a high-resolution database of zonal, meridional and vertical wind, temperature, specific humidity and particle and molecular backscatter and extinction at 355 nm laser wavelength. This allows the simulation of small-scale atmospheric processes within the Aeolus observation sampling volume and their impact on the quality of the retrieved HLOS wind profiles. The database extends over four months covering all seasons. This allows a statistical evaluation of the mission components under investigation. The database is currently used for the development of the Aeolus wind processing, the definition of wind calibration strategies and the optimization of the Aeolus sampling strategy.

High-Resolution Imaging of the Ocean Surface Backscatter by Inversion of Altimeter Waveforms

2011 ◽  
Vol 28 (8) ◽  
pp. 1050-1062 ◽  
Author(s):  
Jean Tournadre ◽  
Bertrand Chapron ◽  
Nicolas Reul
Keyword(s):  
High Resolution ◽  
Significant Wave Height ◽  
Basic Assumption ◽  
Sea Surface ◽  
Small Scale ◽  
High Resolution Imaging ◽  
Small Islands ◽  
Backscatter Coefficient ◽  
High Resolution Images ◽  
Resolution Imaging

Abstract This paper presents a new method to analyze high-resolution altimeter waveforms in terms of surface backscatter. Over the ocean, a basic assumption of modeling altimeter echo waveforms is to consider a homogeneous sea surface within the altimeter footprint that can be described by a mean backscatter coefficient. When the surface backscatter varies strongly at scales smaller than the altimeter footprint size, such as in the presence of surface slicks, rain, small islands, and altimeter echoes can be interpreted as high-resolution images of the surface whose geometry is annular and not rectangular. A method based on the computation of the imaging matrix and its pseudoinverse to infer the surface backscatter at high resolution (~300 m) from the measured waveforms is presented. The method is tested using synthetic waveforms for different surface backscatter fields and is shown to be unbiased and accurate. Several applications can be foreseen to refine the analysis of rain patterns, surface slicks, and lake surfaces. The authors choose here to focus on the small-scale variability of backscatter induced by a submerged reef smaller than the altimeter footprint as the function of tide, significant wave height, and wind.

High-resolution He I 10830 Å Narrowband Imaging for a Small-scale Chromospheric Jet

2021 ◽  
Vol 913 (1) ◽  
pp. 59
Author(s):  
Ya Wang ◽  
Qingmin Zhang ◽  
Haisheng Ji
Keyword(s):  
High Resolution ◽  
Small Scale ◽  
Narrowband Imaging
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