scholarly journals Horizontal Vortex Tubes near a Simulated Tornado: Three-Dimensional Structure and Kinematics

Atmosphere ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 716 ◽  
Author(s):  
Oliveira ◽  
Xue ◽  
Roberts ◽  
Wicker ◽  
Yussouf
Keyword(s):  
Wide Spectrum ◽  
Surface Wind ◽  
3D Structure ◽  
Three Dimensional ◽  
Surface Friction ◽  
Radar Data ◽  
Dimensional Structure ◽  
Small Scale ◽  
Near Surface ◽  
Vortex Tubes

Supercell thunderstorms can produce a wide spectrum of vortical structures, ranging from midlevel mesocyclones to small-scale suction vortices within tornadoes. A less documented class of vortices are horizontally-oriented vortex tubes near and/or wrapping about tornadoes, that are observed either visually or in high-resolution Doppler radar data. In this study, an idealized numerical simulation of a tornadic supercell at 100 m grid spacing is used to analyze the three-dimensional (3D) structure and kinematics of horizontal vortices (HVs) that interact with a simulated tornado. Visualizations based on direct volume rendering aided by visual observations of HVs in a real tornado reveal the existence of a complex distribution of 3D vortex tubes surrounding the tornadic flow throughout the simulation. A distinct class of HVs originates in two key regions at the surface: around the base of the tornado and in the rear-flank downdraft (RFD) outflow and are believed to have been generated via surface friction in regions of strong horizontal near-surface wind. HVs around the tornado are produced in the tornado outer circulation and rise abruptly in its periphery, assuming a variety of complex shapes, while HVs to the south-southeast of the tornado, within the RFD outflow, ascend gradually in the updraft.

scholarly journals Finescale Single- and Dual-Doppler Analysis of Tornado Intensification, Maintenance, and Dissipation in the Orleans, Nebraska, Supercell

2010 ◽  
Vol 138 (12) ◽  
pp. 4439-4455 ◽  
Author(s):  
Joshua Wurman ◽  
Karen Kosiba ◽  
Paul Markowski ◽  
Yvette Richardson ◽  
David Dowell ◽  
...  
Keyword(s):  
Life Cycle ◽  
Surface Wind ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Near Surface ◽  
Wind Speeds ◽  
Gust Fronts ◽  
The Town ◽  
Doppler Analysis ◽  
Observation Period

Abstract Finescale single- and dual-Doppler observations are used to diagnose the three-dimensional structure of the wind field surrounding a tornado that occurred near the town of Orleans, Nebraska, on 22 May 2004. The evolution of the vorticity and divergence fields and other structures near the tornado are documented in the lowest kilometer. Changes in tornado intensity are compared to the position of the tornado relative to primary and secondary gust fronts. Circulation on scales of a few kilometers surrounding the tornado remains relatively constant during the analysis period, which spans the intensifying and mature periods of the tornado’s life cycle. Stretching of vertical vorticity and tilting of horizontal vorticity are diagnosed, but the latter is near or below the threshold of detectability in this analysis during the observation period in the analyzed domain. Low-level circulation within 500 m of the tornado increased several minutes before vortex-relative and ground-relative near-surface wind speeds in the tornado increased, raising the possibility that such trends in circulation may be useful in forecasting tornado intensification.

scholarly journals Site Specific Three-dimensional Structural Analysis in Tissues and Cells Using Automated DualBeam Slice &View

2007 ◽  
Vol 15 (2) ◽  
pp. 26-31 ◽  
Author(s):  
Ben Lich
Keyword(s):  
Electron Microscopy ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Three Dimensional ◽  
Surface Region ◽  
Dimensional Structure ◽  
Near Surface ◽  
Imaging Capability ◽  
Fluorescent Markers ◽  
Confocal And Electron Microscopy

DualBeam instruments that combine the imaging capability of scanning electron microscopy (SEM) with the cutting and deposition capability of a focused ion beam (FIB) provide biologists with a powerful tool for investigating three-dimensional structure with nanoscale (1 nm-100 nm) resolution. Ever since Van Leeuwenhoek used the first microscope to describe bacteria more than 300 years ago, microscopy has played a central role in scientists' efforts to understand biological systems. Light microscopy is generally limited to a useful resolution of about a micrometer. More recently the use of confocal and electron microscopy has enabled investigations at higher resolution. Used with fluorescent markers, confocal microscopy can detect and localize molecular scale features, but its imaging resolution is still limited. SEM is capable of nanometer resolution, but is limited to the near surface region of the sample.

Experiments on wind-driven heat exchange processes over melting snow

2021 ◽  
Author(s):  
Michael Haugeneder ◽  
Tobias Jonas ◽  
Dylan Reynolds ◽  
Michael Lehning ◽  
Rebecca Mott
Keyword(s):  
Snow Cover ◽  
Surface Wind ◽  
Infrared Camera ◽  
Snow Accumulation ◽  
Internal Boundary ◽  
Small Scale ◽  
Snow Melt ◽  
Two Dimensional ◽  
Atmospheric Conditions ◽  
Near Surface

<p>Snowmelt runoff predictions in alpine catchments are challenging because of the high spatial variability of t<span>he snow cover driven by </span>various snow accumulation and ablation processes. In spring, the coexistence of bare and snow-covered ground engages a number of processes such as the enhanced lateral advection of heat over partial snow cover, the development of internal boundary layers, and atmospheric decoupling effects due to increasing stability at the snow cover. The interdependency of atmospheric conditions, topographic settings and snow coverage remains a challenge to accurately account for these processes in snow melt models.<br>In this experimental study, we used an Infrared Camera (VarioCam) pointing at thin synthetic projection screens with negligible heat capacity. Using the surface temperature of the screen as a proxy for the air temperature, we obtained a two-dimensional instantaneous measurement. Screens were installed across the transition between snow-free and snow-covered areas. With IR-measurements taken at 10Hz, we capture<span> the dynamics of turbulent temperature fluctuations</span><span> </span>over the patchy snow cover at high spatial and temporal resolution. From this data we were able to obtain high-frequency, two-dimensional windfield estimations adjacent to the surface.</p><p>Preliminary results show the formation of a stable internal boundary layer (SIBL), which was temporally highly variable. Our data suggest that the SIBL height is very shallow and strongly sensitive to the mean near-surface wind speed. Only strong gusts were capable of penetrating through this SIBL leading to an enhanced energy input to the snow surface.</p><p>With these type of results from our experiments and further measurements this spring we aim to better understand small scale energy transfer processes over patch snow cover and it’s dependency on the atmospheric conditions, enabling to improve parameterizations of these processes in coarser-resolution snow melt models.</p>

Atmospheric Factors Governing Banded Orographic Convection

2005 ◽  
Vol 62 (10) ◽  
pp. 3758-3774 ◽  
Author(s):  
Daniel J. Kirshbaum ◽  
Dale R. Durran
Keyword(s):  
Three Dimensional ◽  
Heavy Precipitation ◽  
Thermal Fluctuations ◽  
Dominant Mode ◽  
Vertical Shear ◽  
Dimensional Structure ◽  
Small Scale ◽  
Atmospheric Structure ◽  
Orographic Convection ◽  
Orographic Cloud

Abstract The three-dimensional structure of shallow orographic convection is investigated through simulations performed with a cloud-resolving numerical model. In moist flows that overcome a given topographic barrier to form statically unstable cap clouds, the organization of the convection depends on both the atmospheric structure and the mechanism by which the convection is initiated. Convection initiated by background thermal fluctuations embedded in the flow over a smooth mountain (without any small-scale topographic features) tends to be cellular and disorganized except that shear-parallel bands may form in flows with strong unidirectional vertical shear. The development of well-organized bands is favored when there is weak static instability inside the cloud and when the dry air surrounding the cloud is strongly stable. These bands move with the flow and distribute their cumulative precipitation evenly over the mountain upslope. Similar shear-parallel bands also develop in flows where convection is initiated by small-scale topographic noise superimposed onto the main mountain profile, but in this case stronger circulations are also triggered that create stationary rainbands parallel to the low-level flow. This second dominant mode, which is less sensitive to the atmospheric structure and the strength of forcing, is triggered by lee waves that form over small-scale topographic bumps near the upstream edge of the main orographic cloud. Due to their stationarity, these flow-parallel bands can produce locally heavy precipitation amounts.

3D Structure of Striations in the North Pacific

2021 ◽  
Author(s):  
YU ZHANG ◽  
YU PING GUAN ◽  
RUI XIN HUANG
Keyword(s):  
North Pacific ◽  
3D Structure ◽  
Three Dimensional ◽  
Vertical Plane ◽  
Dimensional Structure ◽  
The North ◽  
Layer Analysis ◽  
Fluid Potential ◽  
The North Pacific

AbstractOcean striations are composed of alternating quasi-zonal band-like flows; this kind of organized structure of currents be found in all world’s oceans and seas. Previous studies have mainly been focused on the mechanisms of their generation and propagation. This study uses the spatial high-pass filtering to obtain the three-dimensional structure of ocean striations in the North Pacific in both the z-coordinate and σ-coordinate based on 10-yr averaged SODA3 data. First, we identify an ideal-fluid potential density domain where the striations are undisturbed by the surface forcing and boundary effects. Second, using the isopycnal layer analysis, we show that on isopycnal surfaces the orientations of striations nearly follow the potential vorticity (PV) contours, while in the meridional-vertical plane the central positions of striations are generally aligned with the latitude of zero gradient of the relative PV. Our analysis provides a simple dynamical interpretation and better understanding for the role of ocean striations.

scholarly journals Analysis of the three dimensional structure of the kidney glomerulus capillary network

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Mark Terasaki ◽  
Jason Cory Brunson ◽  
Justin Sardi
Keyword(s):  
3D Structure ◽  
Three Dimensional ◽  
The Body ◽  
Capillary Network ◽  
Dimensional Structure ◽  
Pixel Resolution ◽  
Longitudinal Splitting ◽  
Kidney Glomerulus ◽  
Minimum Number ◽  
Glomerular Size

AbstractThe capillary network of the kidney glomerulus filters small molecules from the blood. The glomerular 3D structure should help to understand its function, but it is poorly characterized. We therefore devised a new approach in which an automated tape collecting microtome (ATUM) was used to collect 0.5 μm thick serial sections from fixed mouse kidneys. The sections were imaged by scanning electron microscopy at ~ 50 nm/pixel resolution. With this approach, 12 glomeruli were reconstructed at an x–y–z resolution ~ 10 × higher than that of paraffin sections. We found a previously undescribed no-cross zone between afferent and efferent branches on the vascular pole side; connections here would allow blood to exit without being adequately filtered. The capillary diameters throughout the glomerulus appeared to correspond with the amount of blood flow within them. The shortest path (minimum number of branches to travel from afferent to efferent arterioles) is relatively independent of glomerular size and is present primarily on the vascular pole size. This suggests that new branches and longer paths form on the urinary pole side. Network analysis indicates that the glomerular network does not form by repetitive longitudinal splitting of capillaries. Thus the 3D structure of the glomerular capillary network provides useful information with which to understand glomerular function. Other tissue structures in the body may benefit from this new three dimensional approach.

scholarly journals Molecular Cloning, Modeling, and Characterization of Type 2 Metallothionein from Plantago ovata Forsk

Sequencing ◽  
2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Amitava Moulick ◽  
Debashis Mukhopadhyay ◽  
Shonima Talapatra ◽  
Nirmalya Ghoshal ◽  
Sarmistha Sen Raychaudhuri
Keyword(s):  
Molecular Cloning ◽  
Structure Prediction ◽  
3D Structure ◽  
Three Dimensional ◽  
Transcript Level ◽  
Copper Stress ◽  
Dimensional Structure ◽  
Functional Study ◽  
Plantago Ovata

Plantago ovata Forsk is a medicinally important plant. Metallothioneins are cysteine rich proteins involved in the detoxification of heavy metals. Molecular cloning and modeling of MT from P. ovata is not reported yet. The present investigation will describe the isolation, structure prediction, characterization, and expression under copper stress of type 2 metallothionein (MT2) from this species. The gene of the protein comprises three exons and two introns. The deduced protein sequence contains 81 amino acids with a calculated molecular weight of about 8.1 kDa and a theoretical pI value of 4.77. The transcript level of this protein was increased in response to copper stress. Homology modeling was used to construct a three-dimensional structure of P. ovata MT2. The 3D structure model of P. ovata MT2 will provide a significant clue for further structural and functional study of this protein.

scholarly journals Digital, Three-Dimensional Visualization of Root Systems in Peat

Soil Systems ◽  
2020 ◽  
Vol 4 (1) ◽  
pp. 13 ◽  
Author(s):  
Stella Gribbe ◽  
Gesche Blume-Werry ◽  
John Couwenberg
Keyword(s):  
Root System ◽  
3D Visualization ◽  
Large Diameter ◽  
3D Structure ◽  
Three Dimensional ◽  
Plant Morphology ◽  
Dimensional Structure ◽  
Valuable Insight ◽  
Similar Data ◽  
Soil Matrix

Belowground plant structures are inherently difficult to observe in the field. Sedge peat that mainly consists of partly decayed roots and rhizomes offers a particularly challenging soil matrix to study (live) plant roots. To obtain information on belowground plant morphology, research commonly relies on rhizotrons, excavations, or computerized tomography scans (CT). However, all of these methods have certain limitations. For example, CT scans of peat cores cannot sharply distinguish between plant material and water, and rhizotrons do not provide a 3D structure of the root system. Here, we developed a low-cost approach for 3D visualization of the root system in peat monoliths. Two large diameter (20 cm) peat cores were extracted, frozen and two smaller peat monoliths (47 × 6.5 × 13 cm) were taken from each core. Slices of 0.5 mm or 1 mm were cut from one of the frozen monoliths, respectively, using a paper block cutter and the freshly cut surface of the monolith was photographed after each cut. A 3D model of the fresh (live) roots and rhizomes was reconstructed from the resulting images of the thinner slices based on computerized image analysis, including preprocessing, filtering, segmentation and 3D visualization using the open-source software Fiji, Drishti, and Ilastik. Digital volume measurements on the models produced similar data as manual washing out of roots from the adjacent peat monoliths. The constructed 3D models provide valuable insight into the three-dimensional structure of the root system in the peat matrix.

A Simple Three-Dimensional Terrain Modeling Method for Complex Terrain Wind Environment Simulation

2013 ◽  
Vol 397-400 ◽  
pp. 2420-2425
Author(s):  
Shi Ling Chen ◽  
Jun Lu ◽  
Wei Wei Yu ◽  
Shao Liang Zhang
Keyword(s):  
Complex Terrain ◽  
Cfd Simulation ◽  
Surface Wind ◽  
Three Dimensional ◽  
Modeling Method ◽  
Terrain Modeling ◽  
Wind Environment ◽  
Near Surface ◽  
Digital Modeling ◽  
Environment Simulation

In order to solve the problems in complex terrain modeling by computational fluid dynamics(CFD) simulation at prophase, such as difficulty in collecting data, tedious modeling process, wasting times and so on. In this paper, combined various commonly digital technology，and the transformation between the network terrain file and CFD (PHOENICS) solid model is realized by using a new set of outdoor complex terrain rapid digital modeling method. Take mountain city -Chongqing as an object to analyses the near-surface wind environment. The method is directly generated by the network terrain data without any screening or simplified. The virtual model can be matched the actual terrain with the extreme. By using the simulation cycle for complex terrain, time will be greatly shortened for urban planning.

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