scholarly journals A three-dimensional numerical model of the response of the Australian North West Shelf to tropical cyclones

1994 ◽  
Vol 36 (1) ◽  
pp. 64-100 ◽  
Author(s):  
Songping Zhu ◽  
Jörg Imberger
Keyword(s):  
Tropical Cyclones ◽  
Three Dimensional ◽  
Primitive Equations ◽  
Induced Response ◽  
Temperature Changes ◽  
North West ◽  
The North ◽  
Baroclinic Model ◽  
Induced Currents ◽  
Explicit Finite Difference

AbstractA three-dimensional barotropic and baroclinic model is developed to simulate currents and temperature changes induced by tropical cyclones traversing the continental shelf and slope region of the Australian North West Shelf. The model is based on a layered, explicit, finite difference formulation using the nonlinear primitive equations with an embedded entrainment scheme; a mixed-surface-layer interface is defined, which is allowed to shift from one interface to another, depending on the strength of a storm. The model has been tested by simulating the currents and temperature changes induced by tropical cyclones Orson and Ian. The modelled currents and temperatures agreed well with the available measured records except near the seabed. It has been found that the pre-storm currents have very little influence on the peak of the storm-induced currents and the currents in the wake of a tropical cyclone. The model contained no coefficients which must be calibrated for a particular application and clearly illustrated the importance of the baroclinic effects on the storm-induced response over the North West Shelf of Australia.

scholarly journals Effect of tropical cyclones on the Stratosphere-Troposphere Exchange observed using satellite observations over north Indian Ocean

2016 ◽  
Author(s):  
M. Venkat Ratnam ◽  
S. Ravindra Babu ◽  
S. S. Das ◽  
Ghouse Basha ◽  
B. V. Krishnamurthy ◽  
...  
Keyword(s):  
Water Vapor ◽  
Indian Ocean ◽  
Tropical Cyclones ◽  
Lower Stratosphere ◽  
North Indian Ocean ◽  
Satellite Observations ◽  
Upper Troposphere ◽  
North West ◽  
The North ◽  
The Impact

Abstract. Tropical cyclones play an important role in modifying the tropopause structure and dynamics as well as stratosphere-troposphere exchange (STE) process in the Upper Troposphere and Lower Stratosphere (UTLS) region. In the present study, the impact of cyclones that occurred over the North Indian Ocean during 2007–2013 on the STE process is quantified using satellite observations. Tropopause characteristics during cyclones are obtained from the Global Positioning System (GPS) Radio Occultation (RO) measurements and ozone and water vapor concentrations in UTLS region are obtained from Aura-Microwave Limb Sounder (MLS) satellite observations. The effect of cyclones on the tropopause parameters is observed to be more prominent within 500 km from the centre of cyclone. In our earlier study we have observed decrease (increase) in the tropopause altitude (temperature) up to 0.6 km (3 K) and the convective outflow level increased up to 2 km. This change leads to a total increase in the tropical tropopause layer (TTL) thickness of 3 km within the 500 km from the centre of cyclone. Interestingly, an enhancement in the ozone mixing ratio in the upper troposphere is clearly noticed within 500 km from cyclone centre whereas the enhancement in the water vapor in the lower stratosphere is more significant on south-east side extending from 500–1000 km away from the cyclone centre. We estimated the cross-tropopause mass flux for different intensities of cyclones and found that the mean flux from stratosphere to troposphere for cyclonic stroms is 0.05 ± 0.29 × 10−3 kg m−2 and for very severe cyclonic stroms it is 0.5 ± 1.07 × 10−3 kg m−2. More downward flux is noticed in the north-west and south-west side of the cyclone centre. These results indicate that the cyclones have significant impact in effecting the tropopause structure, ozone and water vapour budget and consequentially the STE in the UTLS region.

scholarly journals The Parcels v2.0 Lagrangian framework: new field interpolation schemes

2019 ◽  
Author(s):  
Philippe Delandmeter ◽  
Erik van Sebille
Keyword(s):  
Three Dimensional ◽  
Analysis Framework ◽  
Interpolation Scheme ◽  
Physical Processes ◽  
North West ◽  
The North ◽  
Lagrangian Framework ◽  
Virtual Particles ◽  
Curvilinear Grids ◽  
Computing Infrastructure

Abstract. With the increasing amount of data produced by numerical ocean models, so increases the need for efficient tools to analyse these data. One of these tools is Lagrangian ocean analysis, where a set of virtual particles are released and their dynamics is integrated in time based on fields defining the ocean state, including the hydrodynamics and biogeochemistry if available. This popular methodology needs to adapt to the large variety of models producing these fields at different formats. This is precisely the aim of Parcels, a Lagrangian ocean analysis framework designed to combine (1) a wide flexibility to model particles of different natures and (2) an efficient implementation in accordance with modern computing infrastructure. In the new Parcels v2.0, we implement a set of interpolation schemes to read various types of discretised fields, from rectilinear to curvilinear grids in the horizontal direction, from z- to s- levels in the vertical and different variable distributions such as the Arakawa's A-, B- and C- grids. In particular, we develop a new interpolation scheme for a three-dimensional curvilinear C-grid and analyse its properties. Parcels v2.0 capabilities, including a suite of meta-field objects, are then illustrated in a brief study of the distribution of floating microplastic in the North West European continental shelf and its sensitivity to different physical processes.

TWO AND THREE DIMENSIONAL ANALOGUE MODELLING OF EXTENSIONAL FAULT SYSTEMS WITH APPLICATION TO THE NORTH WEST SHELF, WESTERN AUSTRALIA.

1994 ◽  
Vol 34 (1) ◽  
pp. 555
Author(s):  
N. M. Lemon ◽  
T. Mahmood
Keyword(s):  
Western Australia ◽  
Three Dimensional ◽  
Sedimentary Sequence ◽  
Progressive Deformation ◽  
Plan View ◽  
North West ◽  
The North ◽  
Analogue Modelling ◽  
Extensional Structures ◽  
Geometry And Kinematics

The North West Shelf of Western Australia is an area of known extensional control with a number of inbuilt complexities related to variations in direction of extension and the existence of early fracture sets. Analogue modelling in a sandbox of modest construction and proportions can imitate the style of structures imaged by seismic on the North West Shelf. Models were constructed to simulate deformation in a sedimentary sequence above simple listric, ramp/flat and complex 3D detachment surfaces. A new 3D technique has been devised to simulate progressive deformation above complex detachment morphologies. Analysis of the structures produced has been achieved by marrying sequential plan view photographs of the model surface with serial vertical sections of the bulk of the model once the experiment has been completed and the sand stabilised. This technique also has the ability to simulate geometry and kinematics of extensional structures in a complex polyphase area. This 3D technique has proven particularly useful in the understanding of structures developed in regions where the sedimentary sequence has been subject to more than one period of extension, each with different orientations. The models provide the first understanding of the areal distribution of fault patterns and associated subsidiary troughs in areas of complex detachments. These models show the distribution of pre-rift and syn-rift sediments in extensional terranes and are valuable in the prediction of deformation in areas of poor seismic quality and for confirmation of seismic interpretation.

scholarly journals Searching for intergalactic star forming regions in Stephan’s Quintet with SITELLE

2019 ◽  
Vol 629 ◽  
pp. A102 ◽  
Author(s):  
S. Duarte Puertas ◽  
J. Iglesias-Páramo ◽  
J. M. Vilchez ◽  
L. Drissen ◽  
C. Kehrig ◽  
...  
Keyword(s):  
Large Scale ◽  
Dwarf Galaxy ◽  
Three Dimensional ◽  
Large Field ◽  
North West ◽  
Star Forming ◽  
Spatially Resolved ◽  
Star Forming Regions ◽  
The North ◽  
Spectral Ranges

Stephan’s Quintet (SQ), the prototypical compact group of galaxies in the local Universe, has been observed with the imaging Fourier transform spectrometer SITELLE, attached to the Canada-France-Hawaii-Telescope, to perform a deep search for intergalactic star-forming emission. In this paper we present the extended ionised gaseous structures detected and analyse their kinematical properties. The large field of view (11′ × 11′) and the spectral ranges of SITELLE have allowed a thorough study of the entire galaxy system, its interaction history and the main properties of the ionised gas. The observations have revealed complex three-dimensional strands in SQ seen for the first time, as well as the spatially resolved velocity field for a new SQ dwarf galaxy (M 82-like) and the detailed spectral map of NGC 7320c, confirming its AGN nature. A total of 175 SQ Hα emission regions have been found, 22 of which present line profiles with at least two kinematical components. We studied 12 zones and 28 sub-zones in the SQ system in order to define plausible physical spatial connections between its different parts in the light of the kinematical information gathered. In this respect we have found five velocity systems in SQ: (i) v = [5600−5900] km s−1 associated with the new intruder and the southern debris region; (ii) v = [5900−6100] km s−1, associated with the north starburst A and south starburst A and the strands connected to these zones; (iii) v = [6100−6600] km s−1, associated with the strands from the large-scale shock region (LSSR); (iv) v = [6600−6800] km s−1, associated with the young tidal tail, the starburst A (SQA), NGC 7319, and the NGC 7319 north lobe; and (v) v = [6800−7000] km s−1, associated with the strands seen connecting LSSR with SQA. We fail to detect ionised gas emission in the old tail, neither in the vicinity of NGC 7318A nor in NGC 7317, and the connection between NGC 7319 north lobe and SQA cannot be confirmed. Conversely, a clear gaseous bridge has been confirmed both spatially and kinematically between the LSSR zone and the NGC 7319 AGN nucleus. Finally, a larger scale, outer rim winding the NGC 7318B/A system clockwise north-west to south-east has been highlighted in continuum and in Hα. This structure may be reminiscent of a sequence of a previously proposed scenario for SQ a sequence of individual interactions.

scholarly journals Comparative analysis of TEC disturbances above regions of tropical cyclones in the north-west Pacific Ocean

10.12737/6594 ◽  
2015 ◽  
Vol 1 (1) ◽  
pp. 63-74
Author(s):  
Анна Полякова ◽  
Anna Polyakova ◽  
Наталья Перевалова ◽  
Natalia Perevalova
Keyword(s):  
Pacific Ocean ◽  
Tropical Cyclones ◽  
Electron Content ◽  
Total Electron ◽  
West Pacific ◽  
Ionospheric Response ◽  
North West ◽  
West Pacific Ocean ◽  
The North ◽  
Typhoon Intensity

We studied ionospheric total electron content (TEC) disturbances associated with tropical cyclones (TCs). The study was based on the statistical analysis of six cyclones with different intensity which occurred in the North-West Pacific Ocean in September–November 2005. We used TEC data from the international network of two-frequency ground-based GPS receivers and NCEP/NCAR Reanalysis meteorological archive. TEC variations of different period ranges (2–20 and 20–60 min) are shown to be more intense during TC peaks under quiet geomagnetic conditions. The highest TEC variation amplitudes are registered when the wind speed in the cyclone and the TC area are maximum. The intensification of TEC disturbances is more pronounced when several cyclones occur simulta-neously. We found that the ionospheric response to TC can be observed only after the cyclone has reached typhoon intensity. The ionospheric response is more pronounced at low satellite elevation angles.

scholarly journals ROLE OF 2D AND 3D MODELS IN JONSDAP '76

1978 ◽  
Vol 1 (16) ◽  
pp. 63
Author(s):  
A.M. Davies
Keyword(s):  
North Sea ◽  
Three Dimensional ◽  
3D Models ◽  
Three Dimensional Model ◽  
North West ◽  
The North ◽  
Dimensional Distribution ◽  
The North Sea ◽  
2D And 3D

This paper describes how a two-dimensional numerical model of the North Sea was used to determine optimum positions for the deployment of off-shore tide gauges during the JONSDAP '76 oceanographic exercise. A three-dimensional model of the North West European Shelf is also described. Using this model the three-dimensional distribution of the M2 tidal current over the shelf has been computed. This model has also been used to compute the wind induced circulation of the North Sea for the INOUT period of JONSDAP '76.

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