scholarly journals Vortex Spinup Process in the Extratropical Transition of Hurricane Sandy (2012)

2019 ◽  
Vol 76 (11) ◽  
pp. 3589-3610 ◽  
Author(s):  
Jung Hoon Shin
Keyword(s):  
Structural Changes ◽  
Outer Region ◽  
Momentum Equation ◽  
Hurricane Sandy ◽  
Core Region ◽  
Local Wind ◽  
Extratropical Transition ◽  
The Core ◽  
Tangential Wind ◽  
Baroclinic Zone

Abstract This study utilizes the quasi-Lagrangian azimuthal momentum equation (i.e., budget calculation) and 1.667-km-resolution numerical simulation data to study the intensity and structural changes in Hurricane Sandy’s extratropical transition. The results indicate that after the onset of extratropical transition, Sandy maintains an eyewall-like convection and warm core in the core region and has a frontal structure in the outer region. In the outer region, baroclinicity-driven frontal convection induces extensive planetary boundary layer (PBL) inflow, causing an inward advection of absolute angular momentum (AAM) per unit radius, which generates outer local wind maxima and expands Sandy’s outer wind field through a spinup process. Moreover, because the outer tangential wind velocity accelerates in a frontal convection, local wind maxima associated with fronts can expand to the outer sides of frontal regions. Frontal convection increases AAM in the outer region, providing the precondition for reintensification; however, the front itself cannot cause Sandy’s reintensification. The eyewall-like convection in the core region still plays an important role in Sandy’s reintensification. When the baroclinic zone, where a strong horizontal temperature gradient exists, approaches the core region, the eyewall-like convection is enhanced because the warm, moist air of the core region is lifted by the cold, dry air associated with the approaching baroclinic zone. Consequently, owing to the enhancement of eyewall-like convection, the PBL inflow, which extends from the outer region to the core region, develops. This inflow increases the inward transportation of the outer frontal region’s high-AAM air, thus leading to spinning up the core region’s wind and reintensification.

scholarly journals A Numerical Study of Cirrus Bands and Low Static-stability Layers associated with Tropical Cyclone Outflow

2021 ◽  
Author(s):  
Masayuki Kawashima
Keyword(s):  
Numerical Study ◽  
Potential Temperature ◽  
Outer Region ◽  
Static Stability ◽  
Core Region ◽  
Thin Layers ◽  
Vertical Shear ◽  
Thermal Gradients ◽  
Shallow Convection ◽  
The Core

AbstractProminent cirrus cloud banding occurred episodically within a northern cirrus canopy of Typhoon Talim (2017) during its recurvature. The generation mechanisms of the cirrus bands and low static-stability layers that support the bands are investigated using a numerical simulation with the Advanced Research Weather Research and Forecasting Model. Inspection of model output reveals that thin layers of near-neutral to weakly unstable static stability are persistently present in the upper and lower parts of the upper-level outflow, and shallow convection aligned along the vertical shear vector is prevalent in these layers. The cirrus banding occurs as the lowered outflow from the weakening storm ascends slantwise over a midlatitude baroclinic zone, and updrafts of the preexisting shallow convection in the upper part of the outflow layer become saturated. It is shown that the strong outflow resulting from violation of gradient-wind balance in the core region, by itself, creates the low static-stability layers. Analyses of potential temperature and static stability budgets show that the low static-stability layers are created mainly by the differential radial advection of radial thermal gradients on the vertical edges of the outflow. The radial thermal gradients occur in response to the outward air parcel acceleration in the core region and deceleration in the outer region, which, by inducing compensating vertical mass transport into and out of the outflow, act to tilt the isentropes within the shear layers. The effects of environmental flow and cloud radiative forcing on the cirrus banding are also addressed.

Observations of the Eyewall Structure of Typhoon Sinlaku (2008) during the Transformation Stage of Extratropical Transition

2014 ◽  
Vol 142 (9) ◽  
pp. 3372-3392 ◽  
Author(s):  
Annette M. Foerster ◽  
Michael M. Bell ◽  
Patrick A. Harr ◽  
Sarah C. Jones
Keyword(s):  
Tropical Cyclones ◽  
Wind Shear ◽  
Doppler Radar ◽  
Vertical Wind Shear ◽  
Core Region ◽  
Vertical Wind ◽  
Naval Research ◽  
Extratropical Transition ◽  
The Core ◽  
Transformation Stage

A unique dataset observing the life cycle of Typhoon Sinlaku was collected during The Observing System Research and Predictability Experiment (THORPEX) Pacific Asian Regional Campaign (T-PARC) in 2008. In this study observations of the transformation stage of the extratropical transition of Sinlaku are analyzed. Research flights with the Naval Research Laboratory P-3 and the U.S. Air Force WC-130 aircraft were conducted in the core region of Sinlaku. Data from the Electra Doppler Radar (ELDORA), dropsondes, aircraft flight level, and satellite atmospheric motion vectors were analyzed with the recently developed Spline Analysis at Mesoscale Utilizing Radar and Aircraft Instrumentation (SAMURAI) software with a 1-km horizontal- and 0.5-km vertical-node spacing. The SAMURAI analysis shows marked asymmetries in the structure of the core region in the radar reflectivity and three-dimensional wind field. The highest radar reflectivities were found in the left of shear semicircle, and maximum ascent was found in the downshear left quadrant. Initial radar echos were found slightly upstream of the downshear direction and downdrafts were primarily located in the upshear semicircle, suggesting that individual cells in Sinlaku’s eyewall formed in the downshear region, matured as they traveled downstream, and decayed in the upshear region. The observed structure is consistent with previous studies of tropical cyclones in vertical wind shear, suggesting that the eyewall convection is primarily shaped by increased vertical wind shear during step 2 of the transformation stage, as was hypothesized by Klein et al. A transition from active convection upwind to stratiform precipitation downwind is similar to that found in the principal rainband of more intense tropical cyclones.

scholarly journals Diurnal Cycle of Rainfall Associated with Landfalling Tropical Cyclones in China from Rain Gauge Observations

2017 ◽  
Vol 56 (9) ◽  
pp. 2595-2605 ◽  
Author(s):  
Hao Hu ◽  
Yihong Duan ◽  
Yuqing Wang ◽  
Xinghai Zhang
Keyword(s):  
Tropical Cyclones ◽  
Diurnal Cycle ◽  
Rain Rate ◽  
Inner Core ◽  
Outer Region ◽  
Rain Gauge ◽  
Core Region ◽  
The Core ◽  
Storm Center ◽  
Landfalling Tropical Cyclones

AbstractThe diurnal variation of rainfall over China associated with landfalling tropical cyclones (TCs) is investigated using hourly rain gauge observations obtained from 2425 conventional meteorological stations in China. Records between 12 h prior to landfall and 12 h after landfall of 450 landfalling TCs in China from 1957 to 2014 are selected as samples. The harmonic analysis shows an obvious diurnal signal in TC rainfall with a rain-rate peak in the early morning and a minimum in the afternoon. The diurnal cycle in the outer region (between 400- and 900-km radii from the storm center) is found to be larger than in the core region (within 400 km of the storm center). This could be attributed to the effect of land on the inner core of the storms as the diurnal cycle is distinct in the core region well before landfall. As the result of this diurnal cycle, TCs making landfall at night tend to have cumulative precipitation, defined as the precipitation cumulated from the time at landfall to 12 h after landfall, about 30% larger than those making landfall around noon or afternoon. Moreover, the radial propagation of the diurnal cycle in TC rain rate, which has been a controversial phenomenon in some previous studies with remote sensing observations, was not present in this study that is based on rain gauge observations. Results also show that the diurnal signal has little dependence on the storm intensity 12 h prior to landfall.

scholarly journals VSOP Observations of the BL Lac Object 2007+777

2001 ◽  
Vol 182 ◽  
pp. 97-100
Author(s):  
C. Jin ◽  
T.P. Krichbaum ◽  
A. Witzel ◽  
R. Nan ◽  
B. Peng ◽  
...  
Keyword(s):  
Structural Changes ◽  
Core Region ◽  
Variable Source ◽  
The Core ◽  
Bl Lac ◽  
5 Ghz ◽  
Source Structure

AbstractWe present three epochs of VSOP observations of the BL Lac object 2007+777 at 5 GHz. Compared with the ground-based VLBA data, the space baselines with HALCA clearly reveal a more detailed and finer source structure. Mainly based on the quite uniform and circular UV-coverages of the VLBA, and using a new cross-selfcalibration method, we have found evidence for weak structural changes on a timescale of two weeks in the core region of this intraday variable source. The physical causes for these variations are discussed.

scholarly journals Structural Analysis of the Core Region of O-Lipopolysaccharide of Porphyromonas gingivalis from Mutants Defective in O-Antigen Ligase and O-Antigen Polymerase

2009 ◽  
Vol 191 (16) ◽  
pp. 5272-5282 ◽  
Author(s):  
Nikolay A. Paramonov ◽  
Joseph Aduse-Opoku ◽  
Ahmed Hashim ◽  
Minnie Rangarajan ◽  
Michael A. Curtis
Keyword(s):  
Porphyromonas Gingivalis ◽  
Inner Core ◽  
Outer Region ◽  
Outer Core ◽  
Core Region ◽  
Resonance Spectroscopy ◽  
Core Oligosaccharide ◽  
Unusual Structure ◽  
The Core ◽  
O Antigen

ABSTRACT Porphyromonas gingivalis synthesizes two lipopolysaccharides (LPSs), O-LPS and A-LPS. Here, we elucidate the structure of the core oligosaccharide (OS) of O-LPS from two mutants of P. gingivalis W50, ΔPG1051 (WaaL, O-antigen ligase) and ΔPG1142 (O-antigen polymerase), which synthesize R-type LPS (core devoid of O antigen) and SR-type LPS (core plus one repeating unit of O antigen), respectively. Structural analyses were performed using one-dimensional and two-dimensional nuclear magnetic resonance spectroscopy in combination with composition and methylation analysis. The outer core OS of O-LPS occurs in two glycoforms: an “uncapped core,” which is devoid of O polysaccharide (O-PS), and a “capped core,” which contains the site of O-PS attachment. The inner core region lacks l(d)-glycero-d(l)-manno-heptosyl residues and is linked to the outer core via 3-deoxy-d-manno-octulosonic acid, which is attached to a glycerol residue in the outer core via a monophosphodiester bridge. The outer region of the “uncapped core” is attached to the glycerol and is composed of a linear α-(1→3)-linked d-Man OS containing four or five mannopyranosyl residues, one-half of which are modified by phosphoethanolamine at position 6. An amino sugar, α-d-allosamine, is attached to the glycerol at position 3. In the “capped core,” there is a three- to five-residue extension of α-(1→3)-linked Man residues glycosylating the outer core at the nonreducing terminal residue. β-d-GalNAc from the O-PS repeating unit is attached to the nonreducing terminal Man at position 3. The core OS of P. gingivalis O-LPS is therefore a highly unusual structure, and it is the basis for further investigation of the mechanism of assembly of the outer membrane of this important periodontal bacterium.

scholarly journals Dust Structure Nearby G229-03

2021 ◽  
Vol 5 (01) ◽  
pp. 2-7
Author(s):  
Hem Shrestha ◽  
Ajay Kumar Jha ◽  
Saroj Nepal ◽  
Aatmaram Tiwari ◽  
Kamana Bantawa ◽  
...  
Keyword(s):  
Inclination Angle ◽  
High Velocity ◽  
Outer Region ◽  
Far Infrared ◽  
Core Region ◽  
Average Temperature ◽  
The Core ◽  
Maximum Temperatures ◽  
Velocity Cloud ◽  
High Velocity Cloud

The Sky View Virtual Observatory was used for the systematic search of dust structures within the far-infrared loop G229-03. The source (object) responsible for the formation of the cavity of interest was detected by the Set of Identifications, Measurements, and Bibliography for Astronomical Data (SIMBAD) database. The total mass of the loop was 8.50031 × 1029 kg which is about 0.425 times the mass of the Sun at a distance of 1300 pc. The size of the cavity was 3.67° × 3.6°, whereas its core size was 0.531° × 0.255° located at R.A. (J2000) = 7h10m0.8s and Dec.(J2000) =15h55m30s. The minimum and maximum temperatures were between 20.24 ± 1.16 K and 18.63 ± 1.96 K respectively. In the core region, the average temperature was 19.53 K, approximately equal to Gaussian center 19.267 K with an offset temperature of 0.4 K showing that the core region of the cavity is dynamically stable. The Far-infrared loop was found to be located within a 1° radius around the high-velocity cloud HVC oriented by 45° to the plane of the sky. The inclination angle of the core of the loop was greater than 60° whereas the inclination angle for the larger structure was 13.71°. The Gaussian distribution of temperature was well fitted with the center of 19.267 K which shows that the cavity was in thermal equilibrium and the outer region with offset temperature of about 35 K suggesting that the loop was dynamically unstable possibly due to high-velocity cloud

scholarly journals A study of far infrared loop at -5o galactic latitude around pulsar J1627-5547

BIBECHANA ◽  
2017 ◽  
Vol 15 ◽  
pp. 70-78
Author(s):  
A K Jha ◽  
B Aryal
Keyword(s):  
Outer Region ◽  
Far Infrared ◽  
Core Region ◽  
Color Temperature ◽  
Galactic Latitude ◽  
Distribution Maps ◽  
The Core ◽  
The Past ◽  
Dust Mass ◽  
Region Size

We present physical properties of the core region of infrared loop G329-05 which is found to be located within 1o from the pulsar PSR J1627-5547.  The loop has 3-fold reduced flux density than its surroundings.  In the 100 micron infrared map, a new cavity-like isolated far infrared dust structure of core region (size ~0.750 x 0.230 ) is  found at R.A. (J2000)= 16h 27m 19.9s & Dec. (J2000) = -56035’14”. This loop is believed to be formed because of high pressure events occurred in the past. The dust color temperature of the core region is found to lie in the range 25.26 ± 0.09 K to 27.91 ± 0.09 K, whereas the value of dust color temperature increased to 36.72 ± 0.18  K for the outer region. The dust color temperature and dust mass distribution maps showed that the low temperature region has greater density as expected. The dust mass of the core region of the loop is found to be 1.67 x 1027 kg i.e. about 0.00835 Mʘ. The core region of the loop is found to be edge-on (i ˃780) whereas the larger structure is faced-on (i =00). Possible explanation of results will be presented.BIBECHANA 15 (2018) 70-76

Phenotype and genotype heterogeneous resistance of L-forms of Mycobacterium tuberculosis by magnetic nanoparticle

2020 ◽  
Vol 10 (1) ◽  
pp. 94-101
Author(s):  
Junlin Chen ◽  
Fei Huang ◽  
Delin Gu ◽  
Mei Qu ◽  
Feifan Xu ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Magnetic Nanoparticle ◽  
Structural Changes ◽  
Rpob Gene ◽  
Core Region ◽  
Medication History ◽  
The Core ◽  
Duration Of Disease ◽  
Resistant Strains ◽  
Drug Resistant Strains

We studied factors influencing the phenotype and genotype heterogeneous resistance of L-forms of Mycobacterium tuberculosis (MTB-L). Three hundred patients with tuberculosis admitted to the Sixth People's Hospital of Nantong from 2014 to 2016 were selected. MTB-L was cultured and rifampicin (RFP) susceptibility was tested using sputum samples. The magnetic nanoparticle was used to extract the DNA of samples. DNA sequencing was used to detect the mutation of the rpoB gene core region for isolated MTB-L strains and heterogeneous resistance was analyzed. A total of 126 MTB-L strains were isolated from the sputum samples of 300 tuberculosis patients. No mutation in the core region of the rpoB gene was detected in 56 RFP-sensitive MTB-L strains. Among 70 phenotypically resistant strains, 32 had mutations in the core region of the rpoB gene, with amino acid changes at sites 511, 516, 526, and 531. No rpoB gene mutation was found in the other 38 phenotypic drug-resistant strains. The MTB-L phenotype and genotype displayed a certain degree of heterogeneous resistance. Changes in cell membrane structure is one important reason. The duration of disease, medication history, and structural changes of the lung are important factors.

Modeling the Effects of Land–Sea Roughness Contrast on Tropical Cyclone Winds

2007 ◽  
Vol 64 (9) ◽  
pp. 3249-3264 ◽  
Author(s):  
Martin L. M. Wong ◽  
Johnny C. L. Chan
Keyword(s):  
Steady State ◽  
Tropical Cyclone ◽  
Sudden Change ◽  
Outer Region ◽  
Radial Dependence ◽  
Strong Constraint ◽  
Gradient Wind ◽  
The Core ◽  
Tangential Wind ◽  
The Right

Abstract The fifth-generation Pennsylvania State University–National Center for Atmospheric Research (PSU–NCAR) Mesoscale Model (MM5) is used to simulate tropical cyclone (TC) wind distribution near landfall. On an f plane at 15°N, the effects of the different surface roughness between the land and sea on the wind asymmetry is examined under a strong constraint of a dry atmosphere and time-invariant axisymmetric mass fields. The winds are found to adjust toward a steady state for prelandfall (50, 100, and 150 km offshore), landfall, and postlandfall (50, 100, and 150 km inland) TC positions. The TC core is asymmetric even when it lies completely offshore or inland. The surface (10 m) wind asymmetry at the core for pre- (post) landfall position is apparently related to the acceleration (deceleration) of the flow that has just moved over the sea (land) as a response to the sudden change of surface friction. For prelandfall TC positions, the resulted strong surface inflow to the left and front left (relative to the direction pointing from sea to land) also induces a tangential (or total) wind maxima at a smaller radius, about 90° downstream of the maximum inflow, consistent with the absolute angular momentum advection (or work done by pressure). The surface maximum wind is of similar magnitude as the gradient wind. There is also a small region of weak outflow just inside the wind maxima. For postlandfall TC positions, inflow is weakened to the right and rear right associated with the onshore flow. Both onshore and offshore flows affect the surface wind asymmetry of the core in the landfall case. Above the surface and near the top of the planetary boundary layer (PBL), the wind is also asymmetric and a strongly supergradient tangential wind is primarily maintained by vertical advection of the radial wind. Much of the steady-state vertical structure of the asymmetric wind is similar to that forced by the motion-induced frictional asymmetry, as found in previous studies. The associated asymmetry of surface and PBL convergences has radial dependence. For example, the landfall case has stronger PBL convergence to the left for the 0–50-km core region, due to the radial inflow, but to the right for the 100–500-km outer region, due to the tangential wind convergence along the coastline. The strong constraint is then removed by considering an experiment that includes moisture, cumulus heating, and the free adjustments of mass fields. The TC is weakening and the sea level pressure has a slightly wavenumber-1 feature with larger gradient wind to the right than to the left, consistent with the drift toward the land. The asymmetric features of the wind are found to be very similar to those in the conceptual experiments.

Intramitochondrial Viruses of Reptilian Cell Origin

1972 ◽  
Vol 30 ◽  
pp. 318-319
Author(s):  
Philip D. Lunger ◽  
H. Fred Clark
Keyword(s):  
Particle Production ◽  
Outer Zone ◽  
Density Variation ◽  
Core Region ◽  
Mitochondrial Membranes ◽  
Virus Particles ◽  
The Core ◽  
Vipera Russelli ◽  
Maturation Stages ◽  
Type Particle

In the course of fine structure studies of spontaneous “C-type” particle production in a viper (Vipera russelli) spleen cell line, designated VSW, virus particles were frequently observed within mitochondria. The latter were usually enlarged or swollen, compared to virus-free mitochondria, and displayed a considerable degree of cristae disorganization.Intramitochondrial viruses measure 90 to 100 mμ in diameter, and consist of a nucleoid or core region of varying density and measuring approximately 45 mμ in diameter. Nucleoid density variation is presumed to reflect varying degrees of condensation, and hence maturation stages. The core region is surrounded by a less-dense outer zone presumably representing viral capsid.Particles are usually situated in peripheral regions of the mitochondrion. In most instances they appear to be lodged between loosely apposed inner and outer mitochondrial membranes.

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