scholarly journals CELLS v1.0: updated and parallelized version of an electrical scheme to simulate multiple electrified clouds and flashes over large domains

2011 ◽  
Vol 4 (4) ◽  
pp. 2849-2892 ◽  
Author(s):  
C. Barthe ◽  
M. Chong ◽  
J.-P. Pinty ◽  
C. Bovalo ◽  
J. Escobar
Keyword(s):  
Negative Ions ◽  
Lightning Flash ◽  
Cloud Particle ◽  
Vertical Extension ◽  
Terrain Following ◽  
Parallel Code ◽  
New Feature ◽  
Convective Cells ◽  
Electrically Charged ◽  
Large Domains

Abstract. The paper describes the fully parallelized electrical scheme CELLS which is suitable to simulate explicitly electrified storm systems on parallel computers. Our motivation here is to show that a cloud electricity scheme can be developed for use on large grids with complex terrain. Large computational domains are needed to perform real case meteorological simulations with many independent convective cells. The scheme computes the bulk electric charge attached to each cloud particle. Positive and negative ions are also taken into account. Several parametrizations of the dominant non-inductive charging process are included and an inductive charging process as well. The electric field is obtained by inverting the Gauss equation with an extension to terrain-following coordinates. The new feature concerns the lightning flash scheme which is a simplified version of an older detailed sequential scheme. Flashes are composed of a bidirectional leader phase (vertical extension from the triggering point) and a phase obeying a fractal law (with horizontal extension on electrically charged zones). The originality of the scheme lies in the way the branching phase is treated to get a parallel code. The complete electrification scheme is tested for the 10 July 1996 STERAO case and for the 21 July 1998 EULINOX case. Flash characteristics are analysed in detail and additional sensitivity experiments are performed for the STERAO case. Although the simulations were run for flat terrain conditions, they show that the model behaves well on multiprocessor computers. This opens a wide area of application for this electrical scheme with the next objective of running real meteorological case on large domains.

scholarly journals CELLS v1.0: updated and parallelized version of an electrical scheme to simulate multiple electrified clouds and flashes over large domains

2012 ◽  
Vol 5 (1) ◽  
pp. 167-184 ◽  
Author(s):  
C. Barthe ◽  
M. Chong ◽  
J.-P. Pinty ◽  
C. Bovalo ◽  
J. Escobar
Keyword(s):  
Negative Ions ◽  
Lightning Flash ◽  
Cloud Particle ◽  
Vertical Extension ◽  
Terrain Following ◽  
Parallel Code ◽  
New Feature ◽  
Convective Cells ◽  
Electrically Charged ◽  
Large Domains

Abstract. The paper describes the fully parallelized electrical scheme CELLS which is suitable to simulate explicitly electrified storm systems on parallel computers. Our motivation here is to show that a cloud electricity scheme can be developed for use on large grids with complex terrain. Large computational domains are needed to perform real case meteorological simulations with many independent convective cells. The scheme computes the bulk electric charge attached to each cloud particle and hydrometeor. Positive and negative ions are also taken into account. Several parametrizations of the dominant non-inductive charging process are included and an inductive charging process as well. The electric field is obtained by inverting the Gauss equation with an extension to terrain-following coordinates. The new feature concerns the lightning flash scheme which is a simplified version of an older detailed sequential scheme. Flashes are composed of a bidirectional leader phase (vertical extension from the triggering point) and a phase obeying a fractal law (with horizontal extension on electrically charged zones). The originality of the scheme lies in the way the branching phase is treated to get a parallel code. The complete electrification scheme is tested for the 10 July 1996 STERAO case and for the 21 July 1998 EULINOX case. Flash characteristics are analysed in detail and additional sensitivity experiments are performed for the STERAO case. Although the simulations were run for flat terrain conditions, they show that the model behaves well on multiprocessor computers. This opens a wide area of application for this electrical scheme with the next objective of running real meterological case on large domains.

Two-way nesting ocean models with different vertical coordinates

2021 ◽  
Author(s):  
Jerome Chanut ◽  
James Harle ◽  
Tim Graham ◽  
Laurent Debreu
Keyword(s):  
Vertical Direction ◽  
Test Cases ◽  
Numerical Representation ◽  
Arbitrary Lagrangian Eulerian ◽  
Coordinate Systems ◽  
Vertical Coordinate ◽  
Terrain Following ◽  
New Feature ◽  
Polynomial Reconstruction ◽  
Horizontal Grid

<p>The NEMO platform possesses a versatile block-structured refinement capacity thanks to the AGRIF library. It is however restricted up to versions 4.0x, to the horizontal direction only. In the present work, we explain how we extended the nesting capabilities to the vertical direction, a feature which can appear, in some circumstances, as beneficial as refining the horizontal grid.</p><p>Doing so is not a new concept per se, except that we consider here the general case of child and parent grids with possibly different vertical coordinate systems, hence not logically defined from each other as in previous works. This enables connecting together for instance z (geopotential), s (terrain following) or eventually ALE (Arbitrary Lagrangian Eulerian) coordinate systems. In any cases, two-way exchanges are enabled, which is the other novel aspect tackled here.  </p><p>Considering the vertical nesting procedure itself, we describe the use of high order conservative and monotone polynomial reconstruction operators to remap from parent to child grids and vice versa. Test cases showing the feasibility of the approach are presented, with particular attention on the connection of s and z grids in the context of gravity flow modelling. This work can be considered as a preliminary step towards the application of the vertical nesting concept over major overflow regions in global realistic configurations. The numerical representation of these areas is indeed known to be particularly sensitive to the vertical coordinate formulation. More generally, this work illustrates the typical methodology from the development to the validation of a new feature in the NEMO model.</p>

scholarly journals Radar Nowcasting of Cloud-to-Ground Lightning over Houston, Texas

2011 ◽  
Vol 26 (2) ◽  
pp. 199-212 ◽  
Author(s):  
Richard M. Mosier ◽  
Courtney Schumacher ◽  
Richard E. Orville ◽  
Lawrence D. Carey
Keyword(s):  
Convective Cell ◽  
Lead Times ◽  
Lightning Flash ◽  
Critical Success ◽  
Lightning Detection ◽  
Doppler Data ◽  
Cloud To Ground Lightning ◽  
A Cell ◽  
Convective Cells ◽  
Critical Success Index

Abstract Ten years (1997–2006) of summer (June–August) daytime (1400–0000 UTC) Weather Surveillance Radar-1988 Doppler data for Houston, Texas, were examined to determine the best radar-derived predictors of the first cloud-to-ground lightning flash from a convective cell. Convective cells were tracked using a modified version of the Storm Cell Identification and Tracking (SCIT) algorithm and then correlated to cloud-to-ground lightning data from the National Lightning Detection Network (NLDN). Combinations of three radar reflectivity values (30, 35, and 40 dBZ) at four isothermal levels (−10°, −15°, −20°, and updraft −10°C) and a new radar-derived product, vertically integrated ice (VII), were used to optimize a radar-based lightning forecast algorithm. Forecasts were also delineated by range and the number of times a cell was identified and tracked by the modified SCIT algorithm. This study objectively analyzed 67 384 unique cells and 1 028 510 lightning flashes to find the best lightning forecast criteria. Results show that using 30 dBZ at the −15° or −20°C isotherm on cells within 75 km of the radar that have been tracked for at least two consecutive scans produces the best lightning forecasts with a critical success index (CSI) of 0.68. The best VII predictor values were 0.42 or 0.58 kg m−2 on cells within 75 km of the radar that have been tracked for at least two consecutive scans, producing a CSI of 0.67. Lead times for these predictors were 10.0 and 13.4 min, respectively. Lead times greater than 10 min occurred with less stringent predictors (e.g., 30 dBZ at −10°C or VII greater than 0.25 kg m−2 on cells within 125 km with a minimum track count of 2), but lower CSI values result. In general, cells tracked for multiple scans provide higher CSIs and lead times than decreasing the range from the radar or changing the reflectivity threshold and height.

scholarly journals Evaluation of a new lightning-produced NO<sub>x</sub> parameterization for cloud resolving models and its associated uncertainties

2008 ◽  
Vol 8 (16) ◽  
pp. 4691-4710 ◽  
Author(s):  
C. Barthe ◽  
M. C. Barth
Keyword(s):  
Convective Cell ◽  
Cloud Base ◽  
Strong Impact ◽  
Lightning Flash ◽  
Flash Rate ◽  
Sensitivity Tests ◽  
Convective Cells ◽  
The Impact ◽  
Lightning Nox ◽  
Good Agreement

Abstract. A new parameterization of the lightning-produced NOx has been developed for cloud-resolving models. This parameterization is based on the unique characteristics of identifying which convective cells are capable of producing lightning based on a vertical velocity threshold and estimating the lightning flash rate in each convective cell from the non-precipitation and precipitation ice mass flux product. Further, the source location is filamentary instead of volumetric as in most previous parameterizations. This parameterization has been tested on the 10 July 1996 Stratospheric-Tropospheric Experiment: Radiation, Aerosols and Ozone (STERAO) storm. Comparisons of the simulated flash rate and NO mixing ratio (control experiment) with observations at different locations and stages of the storm show good agreement. An individual flash produces on average 121±41 moles of NO (7.3±2.5×1025 molecules NO) for the simulated high cloud base, high shear storm that is dominated by intra-cloud flash activity. Sensitivity tests have been performed to study the impact of the flash rate, the cloud-to-ground flash ratio, the flash length, the spatial distribution of the NO molecules, and the production rate per flash on the NO concentration and distribution. Results show a strong impact from the flash rate, the spatial placement of the lightning-NOx source and the number of moles produced per flash. On the other hand, the simulations show almost no impact from the different cloud-to-ground (CG) ratios and the lightning-NOx production rates per CG flash used as input to the model.

Dielectronic Recombination in the Average-Atom Model

1988 ◽  
Vol 102 ◽  
pp. 215
Author(s):  
R.M. More ◽  
G.B. Zimmerman ◽  
Z. Zinamon
Keyword(s):  
Detailed Balance ◽  
Systematic Errors ◽  
Dielectronic Recombination ◽  
Rate Equations ◽  
Strong Correlations ◽  
Dense Plasmas ◽  
Atom Model ◽  
New Feature ◽  
Average Atom Model ◽  
Attachment Process

Autoionization and dielectronic attachment are usually omitted from rate equations for the non–LTE average–atom model, causing systematic errors in predicted ionization states and electronic populations for atoms in hot dense plasmas produced by laser irradiation of solid targets. We formulate a method by which dielectronic recombination can be included in average–atom calculations without conflict with the principle of detailed balance. The essential new feature in this extended average atom model is a treatment of strong correlations of electron populations induced by the dielectronic attachment process.

Kindler's Syndrome with Recurrent Neutropenia: Report of Two Cases from Saudi Arabia

2020 ◽  
Author(s):  
Yousef Binamer ◽  
Muzamil A. Chisti
Keyword(s):  
Autosomal Recessive ◽  
Common Mechanism ◽  
Sequencing Analysis ◽  
Loss Of Function ◽  
Skin Atrophy ◽  
Whole Exome ◽  
Infancy And Childhood ◽  
Genetics And Genomics ◽  
New Feature ◽  
Generation Sequencing

AbstractKindler syndrome (KS) is a rare photosensitivity disorder with autosomal recessive mode of inheritance. It is characterized by acral blistering in infancy and childhood, progressive poikiloderma, skin atrophy, abnormal photosensitivity, and gingival fragility. Besides these major features, many minor presentations have also been reported in the literature. We are reporting two cases with atypical features of the syndrome and a new feature of recurrent neutropenia. Whole exome sequencing analysis was done using next-generation sequencing which detected a homozygous loss-of-function (LOF) variant of FERMT1 in both patients. The variant is classified as a pathogenic variant as per the American College of Medical Genetics and Genomics guidelines. Homozygous LOF variants of FERMT1 are a common mechanism of KS and as such confirm the diagnosis of KS in our patients even though the presentation was atypical.

Pattern Recognition for Classification and Matching of Car Tires

2005 ◽  
Vol 33 (1) ◽  
pp. 2-17 ◽  
Author(s):  
D. Colbry ◽  
D. Cherba ◽  
J. Luchini
Keyword(s):  
Computer Vision ◽  
Feature Extraction ◽  
Pattern Matching ◽  
Fourier Transforms ◽  
Two Dimensions ◽  
Multiple Sources ◽  
Matching Process ◽  
Visual Searches ◽  
New Feature ◽  
2D Fft

Abstract Commercial databases containing images of tire tread patterns are currently used by product designers, forensic specialists and product application personnel to identify whether a given tread pattern matches an existing tire. Currently, this pattern matching process is almost entirely manual, requiring visual searches of extensive libraries of tire tread patterns. Our work explores a first step toward automating this pattern matching process by building on feature analysis techniques from computer vision and image processing to develop a new method for extracting and classifying features from tire tread patterns and automatically locating candidate matches from a database of existing tread pattern images. Our method begins with a selection of tire tread images obtained from multiple sources (including manufacturers' literature, Web site images, and Tire Guides, Inc.), which are preprocessed and normalized using Two-Dimensional Fast Fourier Transforms (2D-FFT). The results of this preprocessing are feature-rich images that are further analyzed using feature extraction algorithms drawn from research in computer vision. A new, feature extraction algorithm is developed based on the geometry of the 2D-FFT images of the tire. The resulting FFT-based analysis allows independent classification of the tire images along two dimensions, specifically by separating “rib” and “lug” features of the tread pattern. Dimensionality of (0,0) indicates a smooth treaded tire with no pattern; dimensionality of (1,0) and (0,1) are purely rib and lug tires; and dimensionality of (1,1) is an all-season pattern. This analysis technique allows a candidate tire to be classified according to the features of its tread pattern, and other tires with similar features and tread pattern classifications can be automatically retrieved from the database.

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