scholarly journals The Influence of Island Topography on Typhoon Track Deflection

2011 ◽  
Vol 139 (6) ◽  
pp. 1708-1727 ◽  
Author(s):  
Yi-Hsuan Huang ◽  
Chun-Chieh Wu ◽  
Yuqing Wang
Keyword(s):  
High Resolution ◽  
Inner Core ◽  
Realistic Model ◽  
Cloud Microphysics ◽  
The North ◽  
Steering Flow ◽  
Typhoon Track ◽  
Physics Model ◽  
Channeling Effect ◽  
Prediction And Simulation

Abstract High-resolution simulations for Typhoon Krosa (2007) and a set of idealized experiments are conducted using a full-physics model to investigate the eminent deflection of typhoon track prior to its landfall over mountainous island topography. The terrain height of Taiwan plays the most important role in Typhoon Krosa’s looping motion at its landfall, while the surface properties, details in the topographic shape of Taiwan, and the cloud microphysics are shown to be secondary to the track deflection. A simulation with 3-km resolution and realistic model settings reproduces the observed Krosa’s track, while that with 9-km resolution fails, suggesting that high resolution to better resolve the typhoon–terrain interactions is important for the prediction and simulation of typhoon track deflection prior to landfall. Results from idealized experiments with model configurations mimicking those of Supertyphoon Krosa show that vortices approaching the northern and central topography are significantly deflected to the south before making sharp turns to the north, forming a kinked track pattern prior to and during landfall. This storm movement is consistent with the observed looping cases in Taiwan. Both real-case and idealized simulations show strong channel winds enhanced between the storm and the terrain when deflection occurs. Backward trajectory analyses support the concept of the channeling effect, which has been previously found to be crucial to the looping motion of Typhoon Haitang (2005) as well. However, the inner-core asymmetric ventilation flow does not match the movement of a deflected typhoon perfectly, partly because the steering flow is not well defined and could not completely capture the terrain-induced deflection in the simulation and in nature.

scholarly journals A Numerical Study of the Track Deflection of Supertyphoon Haitang (2005) Prior to Its Landfall in Taiwan

2008 ◽  
Vol 136 (2) ◽  
pp. 598-615 ◽  
Author(s):  
Guo-Ji Jian ◽  
Chun-Chieh Wu
Keyword(s):  
Control Experiment ◽  
Inner Core ◽  
Numerical Study ◽  
Sensitivity Study ◽  
Weather Research And Forecasting ◽  
Translation Speed ◽  
Fine Mesh ◽  
Steering Flow ◽  
Moving Storm ◽  
Channeling Effect

Abstract A series of numerical simulations are conducted using the advanced research version of the Weather Research and Forecasting model with a 4-km fine mesh to examine the physical processes responsible for the significant track deflection and looping motion before the landfall of Supertyphoon Haitang (2005) in Taiwan, which poses a unique scientific and forecasting issue. In the control experiment, a low-level northerly jet induced by the channeling effect forms in the western quadrant of the approaching storm, where the inner-core circulation is constrained by the presence of Taiwan’s terrain. Because of the channeling effect, the strongest winds of the storm are shifted to the western portion of the eyewall. The northerly advection flow (averaged asymmetric winds within 100-km radius) results in a sharp southward turn of the westward-moving storm. The time series of the advection flow shows that the advection wind vectors rotate cyclonically in time and well match the motion of the simulated vortex during the looping process. A sensitivity study of lowering the Taiwan terrain elevations to 70% or 40% of those in the control experiment reduces the southward track deflection and loop amplitude. The experiment with the reduced elevation to 10% of the control experiment does not show a looping track and thus demonstrates the key role of the terrain-induced channeling effect. Experiments applying different values of the structure parameter α illustrate that increasing the strength, size, and translation speed of the initial storm results in a smaller interaction with Taiwan’s terrain and a smaller average steering flow caused by the asymmetric circulation, which leads to a proportionally smaller southward track deflection without making a loop.

scholarly journals Monsoon Mission: A Targeted Activity to Improve Monsoon Prediction across Scales

2019 ◽  
Vol 100 (12) ◽  
pp. 2509-2532 ◽  
Author(s):  
Suryachandra A. Rao ◽  
B. N. Goswami ◽  
A. K. Sahai ◽  
E. N. Rajagopal ◽  
P. Mukhopadhyay ◽  
...  
Keyword(s):  
High Resolution ◽  
Land Surface ◽  
Prediction Models ◽  
Seasonal Prediction ◽  
Cloud Microphysics ◽  
Prediction System ◽  
Forecast System ◽  
Present Generation ◽  
Coupled Data Assimilation ◽  
Prediction And Simulation

Abstract In spite of the summer monsoon’s importance in determining the life and economy of an agriculture-dependent country like India, committed efforts toward improving its prediction and simulation have been limited. Hence, a focused mission mode program Monsoon Mission (MM) was founded in 2012 to spur progress in this direction. This article explains the efforts made by the Earth System Science Organization (ESSO), Ministry of Earth Sciences (MoES), Government of India, in implementing MM to develop a dynamical prediction framework to improve monsoon prediction. Climate Forecast System, version 2 (CFSv2), and the Met Office Unified Model (UM) were chosen as the base models. The efforts in this program have resulted in 1) unparalleled skill of 0.63 for seasonal prediction of the Indian monsoon (for the period 1981–2010) in a high-resolution (∼38 km) seasonal prediction system, relative to present-generation seasonal prediction models; 2) extended-range predictions by a CFS-based grand multimodel ensemble (MME) prediction system; and 3) a gain of 2-day lead time from very high-resolution (12.5 km) Global Forecast System (GFS)-based short-range predictions up to 10 days. These prediction skills are on par with other global leading weather and climate centers, and are better in some areas. Several developmental activities like coupled data assimilation, changes in convective parameterization, cloud microphysics schemes, and parameterization of land surface processes (including snow and sea ice) led to the improvements such as reducing the strong model biases in the Indian summer monsoon simulation and elsewhere in the tropics.

Convectively Generated Potential Vorticity in Rainbands and Formation of the Secondary Eyewall in Hurricane Rita of 2005

2010 ◽  
Vol 67 (11) ◽  
pp. 3581-3599 ◽  
Author(s):  
Falko Judt ◽  
Shuyi S. Chen
Keyword(s):  
High Resolution ◽  
Potential Vorticity ◽  
Inner Core ◽  
Intensity Change ◽  
Initial Development ◽  
Hurricane Rita ◽  
Key Factor ◽  
Physics Model ◽  
Hurricanes Katrina And Rita ◽  
Pv Generation

Abstract Eyewall replacements in mature tropical cyclones usually cause intensity fluctuations. One reason for eyewall replacements remaining a forecasting challenge is the lack of understanding of how secondary eyewalls form. This study uses high-resolution, full-physics-model forecast fields of Hurricanes Katrina and Rita (2005) to better understand potential vorticity (PV) generation in the rainbands and the role that convectively generated PV played in the formation of a secondary eyewall in Hurricane Rita. Previous studies have focused on dynamic processes in the inner core and/or the effects of certain specified PV distributions. However, the initial development of a concentric PV ring in the rainband region has not been fully addressed. Katrina and Rita were extensively observed by three research aircraft during the Hurricane Rainband and Intensity Change Experiment (RAINEX), which was designed to study the interaction of the rainbands and the inner core. Rita developed a secondary eyewall and went through an eyewall replacement cycle, whereas Katrina maintained a single primary eyewall during the RAINEX observation period before landfall. These distinct features observed in RAINEX provide a unique opportunity to examine the physical and dynamical processes that lead to formation of concentric eyewalls. A triply nested high-resolution model with 1.67-km resolution in the innermost domain, initialized with operational model forecasts in real time during RAINEX, is used in this study. Analyses of wind, vorticity, PV, and vortex Rossby wave (VRW) activity in the inner-core region were conducted using both RAINEX airborne observations and model output. The results show that a higher PV generation rate and accumulation in the rainband region in Rita leads to a secondary PV/vorticity maximum, which eventually became the secondary eyewall. A strong moat area developed between the primary eyewall and the concentric ring of convection in Rita, prohibiting VRW activity. In contrast, VRWs propagated radially outward from the inner core to the rainband region in Katrina. The VRWs were not a contributing factor in the initial formation of the secondary eyewall in Rita since the moat region with near-zero PV gradient did not allow for radial propagation of VRWs. The large accumulation of convectively generated PV in the rainband region was the key factor in the formation of the secondary eyewall in Rita.

scholarly journals A high-resolution solar spectrum 2000 Å–2200 Å

1970 ◽  
Vol 36 ◽  
pp. 271-273
Author(s):  
B. B. Jones ◽  
B. C. Boland ◽  
R. Wilson ◽  
S. T. F. Engstrom
Keyword(s):  
High Resolution ◽  
Solar Spectrum ◽  
Solar Image ◽  
Roll Control ◽  
North East ◽  
The North ◽  
Alignment System ◽  
Optical Alignment ◽  
South Axis ◽  
System Operating

A high-resolution solar spectrum in the range 2000–2200 Å was obtained in a recent flight of a sunpointing Skylark rocket. This was launched at 04.21 hr UT on April 22, 1969 from Woomera and reached an apogee of 178 km. An optical alignment system operating on the main vehicle pointing system gave a net stabilisation of ±3 arc sec in the position of the solar image relative to the spectrograph slit. The slit, of length 1.0 mm, was set in the north-east quadrant parallel to and 5 arc min from the north/south axis, its lower edge being 1 arc min from the equator. The roll control of ±2.5° was provided entirely by the standard Elliott Bros. type of vehicle stabilisation.

X-ray computed microtomography for the structural analysis of jewelry from the Museum “Royal Tombs of Sipán”

2020 ◽  
Vol 35 (S1) ◽  
pp. S38-S42
Author(s):  
Soraia Rodrigues de Azeredo ◽  
Roberto Cesareo ◽  
Angel Guillermo Bustamante Dominguez ◽  
Ricardo Tadeu Lopes
Keyword(s):  
Structural Analysis ◽  
High Resolution ◽  
Copper Alloys ◽  
North Coast ◽  
Flat Panel ◽  
X Ray ◽  
The North ◽  
Gold Silver ◽  
Computed Microtomography ◽  
X Ray Computed

Precious ornaments from the Museum Royal Tombs of Sipán were analyzed by X-ray computed microtomography (microCT). The ornaments analyzed were golden earrings produced by the Moche culture that flourished along the north coast of present-day Peru between approximately 100 and 600 AD. Sipán, also known as Huava Rajada, is a mochica archaeological complex in the north of Peru. In particular, the spectacular jewelry, mainly composed of gold, silver, and copper alloys, gilded copper, and tumbaga, from the Museum “Royal Tombs of Sipán,” in Lambayeque, north of Peru, are some of the most sophisticated metalworking ever produced of pre-Columbian America. A portable microCT system consisting of a high-resolution flat panel detector and a mini X-ray tube were used for the structural analysis of these ornaments. The microCT images show parts of the internal structure, highlighting the manufacturing technique and gold sheets joining techniques of the Moche artisans. Furthermore, the advantage of using the portable microCT system for nondestructive testing is clear when the sample cannot be taken to the laboratory.

scholarly journals Revisiting the Balanced and Unbalanced Aspects of Tropical Cyclone Intensification

2017 ◽  
Vol 74 (8) ◽  
pp. 2575-2591 ◽  
Author(s):  
Junyao Heng ◽  
Yuqing Wang ◽  
Weican Zhou
Keyword(s):  
Boundary Layer ◽  
Tropical Cyclone ◽  
Inner Core ◽  
Model Simulation ◽  
Surface Friction ◽  
Core Region ◽  
Physics Model ◽  
The One ◽  
Balanced Dynamics ◽  
Balanced Solution

Abstract The balanced and unbalanced aspects of tropical cyclone (TC) intensification are revisited with the balanced contribution diagnosed with the outputs from a full-physics model simulation of a TC using the Sawyer–Eliassen (SE) equation. The results show that the balanced dynamics can well capture the secondary circulation in the full-physics model simulation even in the inner-core region in the boundary layer. The balanced dynamics can largely explain the intensification of the simulated TC. The unbalanced dynamics mainly acts to prevent the boundary layer agradient flow in the inner-core region from further intensification. Although surface friction can enhance the boundary layer inflow and make the inflow penetrate more inward into the eye region, contributing to the eyewall contraction, the net dynamical effect of surface friction on TC intensification is negative. The sensitivity of the balanced solution to the procedure used to ensure the ellipticity condition for the SE equation is also examined. The results show that the boundary layer inflow in the balanced response is very sensitive to the adjustment to inertial stability in the upper troposphere and the calculation of radial wind at the surface with relatively coarse vertical resolution in the balanced solution. Both the use of the so-called global regularization and the one-sided finite-differencing scheme used to calculate the surface radial wind in the balanced solution as utilized in some previous studies can significantly underestimate the boundary layer inflow. This explains why the boundary layer inflow in the balanced response is too weak in some previous studies.

789 HIGH RESOLUTION ESOPHAGEAL MOTILITY: VARIABLE GEOGRAPHIC DISTRIBUTION IN A LARGE MEXICAN COHORT

2021 ◽  
Vol 34 (Supplement_1) ◽  
Author(s):  
Genaro Vazquez-Elizondo ◽  
José María Remes-Troche ◽  
Enrique Coss-Adame ◽  
Edgardo Suárez-Morán ◽  
Miguel Ángel Valdovinos-Díaz ◽  
...  
Keyword(s):  
High Resolution ◽  
Data Base ◽  
Regional Differences ◽  
Outlet Obstruction ◽  
Central Mexico ◽  
Diverse Population ◽  
Chi Square ◽  
The North ◽  
Available Information ◽  
Diagnostic Outcome

Abstract   High resolution esophageal manometry (HREM) has been in use for about a decade. However, there is no available information regarding geographical or regional differences in diagnostic outcome. Aim Characterize the indications, demographics and diagnostic outcome of HREM in a diverse population of Mexico. Methods Data was collected from four major referral centers representing diverse geographical areas of Mexico: central—Mexico City (two centers, years 2016-2020), south (Veracruz, years 2015-2020) and north (Monterrey, years 2013—2020). All consecutive cases referred for HREM were entered into a data base and analyzed using Chicago 3 classification. Data was evaluated using chi-square to compare frequencies among groups. Results 2,932 patients included: Central n = 877(29.9), North n = 1003(34.2), South n = 1052(35.9). Mean age 47.9(11-93), women 1,795(61.2), men 1,137(38.8). Nationwide, the most common indications for testing were: GERD n = 1677(57.2), followed by dysphagia 587(20), atypical GERD 244(8.3), post-operative GERD 230(7.9), chest pain 114(3.9), and post-operative dysphagia 78(2.8). HREM was normal in 1,468(49.9) patients. Table shows the diagnostic distribution among centers: Central-Mexico had more abnormal cases 531(60.5) (p < 0.0.001) vs 407(40.6) North and 532(50.6) South. Achalasia was more commonly diagnosed in the South n = 104(19.5) whereas outlet obstruction 39(967) p < 0.001 and spastic disorders were more common in the North 47(11.8) p = 0.002. Weak peristaltic disorders were more common in Central-Mexico 369(78.8) p < 0.001. Conclusion This study represents the first large comparative multicenter HREM data base project in Mexico. In this cohort, most patients receiving HREM are women and those whose indication was GERD. These findings indicate variable regional geographical distribution of HERM diagnosis. Our study suggests that further investigation into the causes and epidemiological distribution of motility disorders is warranted.

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