idealized simulations of the effect of taiwan and philippines topographies on tropical cyclone tracks the effects of topography on tropical cyclone tc tracks are investigated using the weather research and forecasting model running on a beta plane with actual topography two sets of experiments are performed one focusing on taiwan topography and the other on the philippines in each set different parts of the terrain are set to be either present or absent and the tcs are inserted at a location southeast of the mountain so that landfall occurs at the central part of the mountain in the no terrain control cases relative to the control case a pair of terrain induced gyres is found in all with terrain experiments this pair of gyres rotates cyclonically around the tc and the gyre associated flow near the tc centre causes a northward deflection of the tc track prior to landfall an examination of the potential vorticity tendencies pvts suggests that in addition to the pvt produced by this flow the pvt from diabatic heating cannot be ignored in explaining the tc track during landfall the asymmetric diabatic heating is significant which tends to retard the fast displacement of the tc caused by horizontal advection this diabatic heating distribution results from three different mechanisms an incursion of dry air from the mountain low level convergence induced by the terrain altered wind field in the southwestern part of the tc and the development of convergence cyclonically inward from the eastern side of the mountain to the tc core however the first two mechanisms are apparently missing in the philippine experiments because of the lower height and the moister air over the mountains on luzon island

idealized simulations of the effect of local and remote topographies on tropical cyclone tracks this is the second part of a study on the effect of topography on tropical cyclone tc tracks in part i idealized simulations using the weather research and forecast wrf model were conducted with artificial tcs inserted at a location such that they make landfall on the central part of taiwan and the luzon in this second part the effects of local and remote topographies are studied by examining the tracks of several tcs approaching taiwan at different latitudes tropical cyclones approaching to the south of taiwan remote effect slow down and are first deflected southwestward and then northward moreover a sharp northward deflection occurs for a tc passing further south of taiwan but the deflection is small for a tc passing further north of taiwan in the presence of china s terrain an additional larger but weaker anticyclonic gyre is induced so that the tc is affected even when it is further away from the land the flow associated with this gyre reduces the northward deflection caused by the taiwan terrain but enhances the southwestward shift of the tc however no cyclonic gyre is found over inland china if the tc is far away from china s coast probably because of the irregular elevated topography for tcs making landfall on south china a westward shift is found just prior to landfall which is more significant if the height of china s terrain is doubled this westward shift can be explained by the horizontal advection vertical advection and diabatic heating terms in the potential vorticity tendency equation

shrimp u pb zircon dating of grenville age events in the western part of the musgrave block central australia shrimp u pb zircon dating of structurally constrained felsic orthogneiss samples in the western musgrave block has been used to delineate discrete magmatic and metamorphic events at c 1300 and c 1200 ma the dating of pre d1 and post d1 felsic orthogneiss constrains d1 to have occurred at 1312 16 to 1324 4 ma this is the first geochronological study to identify such a metamorphic and deformation event in the musgrave block d1 was accompanied by a major magmatic event involving the emplacement of voluminous felsic orthogneiss between 1296 and 1324 ma zircon overgrowths on numerous igneous zircon cores give a consistent age of c 1200 ma reflecting zircon growth during a second high grade metamorphic event d2 this c 1200 ma metamorphic event was followed by the intrusion of a c 1190 ma megacrystic granite the c 1300 and c 1200 ma events in the musgrave block can be tentatively correlated with metamorphic events in the albany fraser orogen and the windmill islands and bunger hills in east antarctica a major continuous grenville age orogenic belt joining these areas may have represented a plate boundary between the pre rodinian proto australian continent and proto antarctica during the formation of rodinia in the mesoproterozoic

influence of mesoscale topography on tropical cyclone tracks further examination of the channeling effect abstractobservations have documented typhoons experiencing pronounced track deflection before making landfall in taiwan in this study idealized full physics model experiments are conducted to assess the orographic influence on tropical cyclone tc track an intense and westward moving tc is simulated to approach the bell shaped terrain imitating the taiwan topography sensitivity numerical experiments are carried out to evaluate the topographic effect under different flow regimes and parameters such as tc intensity terrain height and incident angle of the tc movement toward the topography all the presented simulated storms experience southward track deflection prior to landfall different from the mechanism related to the channeling effect induced low level northerly jet as suggested in previous studies this study indicates the leading role of the northerly asymmetric flow in the midtroposphere in causing the southward deflection of the simulated tc tracks the midtropospheric northerly asymmetric

some isotopic constraints on the evolution of the granulite and upper amphibolite facies terranes in the eastern musgrave block central australia abstract the central to eastern musgrave block central australia consists of the meso to neoproterozoic fregon and mulga park subdomains that are separated by a zone of mylonites and pseudotachylytes known as the woodroffe thrust the subdomains were previously considered to have undergone different geological histories but the differences relate mainly to metamorphic grade the fregon subdomain attained at least transitional granulite facies metamorphic conditions and the mulga park subdomain reached upper amphibolite facies felsic gneisses from both the fregon and mulga park subdomains contain zircons that are structured with euhedral centres overgrown by round elongate rims ion microprobe u pb analyses of the cores yield ages of 1557 24 and 1554 28 ma respectively and are interpreted to represent the time of igneous crystallization these ages place a maximum age constraint on the deposition or emplacement of the gneiss precursor high grade metamorphism grading from upper amphibolite to granulite facies took place between 1200 and 1150 ma and prior to the intrusion of several granitoid suites at around 1150 ma the kulgera adamellite and ayers ranges adamellite granitoid suites of the fregon subdomain yield ion microprobe u pb crystallization ages of 1150 12 and 1152 11 ma respectively a concordant u pb isotope dilution analysis on the ayers ranges adamellite yields a more precise age of 1152 3 ma the porphyritic suite intruding the mulga park subdomain yield an ion microprobe u pb magmatic age of 1159 20 ma these emplacement ages indicate extensive grenvillian felsic magmatism not previously recognized in australia the woodroffe thrust formed during a period of substantial crustal shortening the petermann orogeny 550 ma when the fregon subdomain was thrust onto the mulga park subdomain synkinematic muscovite and biotite record k ar and rb sr ages between 560 and 520 ma this petermann event is not recorded in the fregon subdomain due to confinement of the strain and associated mineral recrystallization to the underlying mulga park subdomain we suggest that the granulites were not exposed prior to the petermann orogeny as the basal quartzites of the amadeus basin occur only on the amphibolite facies mulga park subdomain

orographic influence on basic flow and cyclone circulation and their impacts on track deflection of an idealized tropical cyclone abstracta series of idealized numerical experiments and vorticity budget analyses is performed to examine several mechanisms proposed in previous studies to help understand the orographic influence on track deflection over a mesoscale mountain range when an idealized tropical cyclone tc is embedded in a uniform easterly flow and passes over a mountain with a moderate froude number it is deflected to the south upstream moves over the mountain anticyclonically and then resumes its westward movement the vorticity budget analysis indicates that the tc movement can be predicted by the maximum vorticity tendency vt the orographic effects on the above tc track deflection are explained by the following 1 upstream of the mountain the easterly basic flow is decelerated as a result of orographic blocking that causes the flow to become subgeostrophic which advects the tc to the southwest analogous to the advection of a point vortex embedded in a flow the vt is primarily dominated by the horizontal vo

1 8 1 5 ga links between the north and south australian cratons and the early middle proterozoic configuration of australia abstract the archaean and early middle proterozoic 1 8 1 5 ga terranes of the north australian craton and the south australian craton are separated by 400 km of ca 1 33 1 10 ga orogenic belts and phanerozoic sediments however there is a diverse range of geological phenomena that correlate between the component terranes of the two cratons and provide evidence for a shared tectonic evolution between approximately 1 8 and 1 5 ga in order to honour these correlations we propose a reconstruction in which the south australian craton is rotated 52 counterclockwise about a pole located at 136 e and 25 s present day coordinates relative to its current position this reconstruction aligns the ca 1 8 1 6 ga orogenic belts preserved in the arunta inlier and the gawler craton and the ca 1 6 1 5 ga orogenic belts preserved in the mount isa block and the curnamona province before 1 5 ga the south australian craton was not a separate entity but part of a greater proto australian continent which was characterised by accretion along a southward migrating convergent margin ca 1 8 1 6 ga followed by convergence along the eastern margin ca 1 6 1 5 ga after 1 5 ga the south australian craton broke away from the north australian craton only to be reattached in its current position during the ca 1 33 1 10 ga albany fraser and musgrave orogenies

the mechanism of ascent and emplacement of granite magma during transpression a syntectonic granite paradigm we propose a model for syntectonic ascent and emplacement of granite magma based on structural relations in part of the northern appalachians in the study area in western maine strain was distributed heterogeneously during devonian acadian transpression metasedimentary rocks migmatites at high grades record two contrasting types of finite strain in zones that alternate across strike rocks in both types of zones have a penetrative moderately to steeply ne plunging mineral elongation lineation defined by bladed muscovite fibrolite sillimanite at high grades in straight belts of enhanced deformation rocks have s l fabrics that record apparent flattening to plane strain apparent flattening zones afzs but rocks between these belts have l s fabrics that record apparent constriction apparent constriction zones aczs at metamorphic grades above the contemporary solidus rocks in afzs developed stromatic structure in migmatite which suggests that percolative flow of melt occurred along the evolving flattening fabric stromatic migmatites are intruded by concordant to weakly discordant m scale composite sheet like bodies of granite to suggest magma transport in planar conduits through the afz rocks inhomogeneous migmatite is found in the intervening aczs which suggests migration of partially molten material through these zones en masse probably by melt assisted granular flow inhomogeneous migmatites are intruded by irregular m scale bodies of granite that vary from elongate to sub circular in plan view and seem cylindrical in three dimensions these bodies apparently plunge to the northeast parallel to the regional mineral elongation lineation to suggest magma transport in pipe like conduits through the acz rocks we postulate that the form of magma ascent conduits was deformation controlled and was governed by the contemporaneous strain partitioning magma ascent in planar and pipe like conduits through migmatites is possible because oblique translation during contraction displaces isotherms upward in the orogenic crust to form a thermal antiform within this hot corridor it is the difference in temperature between melt producing reactions in the anatectic zone and the wet solidus for granite melt that enables magma to migrate pervasively up through the orogenic crust without congealing heat advected with the migrating melt promotes amplification of the thermal antiform in a feedback relation that extends the zone of plastic deformation and pervasive melt migration to shallower levels in the crust at the wet solidus we suggest melt flows obliquely toward axial culminations in the thermal antiform which are sites of melt accumulation and perturbations from which magma may escape to form plutons batches of melt that escape from these perturbations may be trapped by tectonic structures higher in the crust or ascent may become inhibited with decreasing depth by thermal arrest and solidification if the rate of arrival of subsequent melt batches exceeds the rate of crystallization at the site of pluton construction melt pressure ultimately may lead to sub horizontal magma fracture or viscous flow of wall rocks may allow lateral spreading the resultant plutons have sub horizontal tabular geometries with floors that slope down to the ascent conduit as the thermal antiform decays the height of sub solidus crust that separates the deepest part of the pluton from the anatectic zone increases consequently pluton inflation declines and solidification leads to infilling of the magma feeder channel to form a root zone that passes downward into migmatite which may explain the difficulty of determining precisely the floor to these deeper segments of large plutons using gravimetry

sensitivity of typhoon track to asymmetric latent heating rainfall induced by taiwan topography a numerical study of typhoon fanapi 2010 1 typhoon fanapi 2010 traveled westward across the central mountain range of taiwan on 19 september and its rainfall shifted from a symmetric to an asymmetric pattern with convection mostly to the south and southeast meanwhile the storm slowed down from 22 to 14 km h 1 for 12 h upon leaving taiwan and led to heavy rainfall 800 mm and serious flooding over the low lying southwestern plains through simulation and sensitivity tests using the cloud resolving storm simulator at 3 km grid size this study shows that the sudden and temporary speed reduction was caused by the asymmetric latent heating lh not the environmental flow specifically over a 9 h period the model storm moved westward at 16 km h 1 in the control run but increasingly faster and more toward the northwest when the moisture and thus the lh effect and its asymmetry is gradually reduced steering flow analysis and estimation using model results suggest an eastward motion vector of about 8 km h 1 consistent with the observation is produced by the asymmetric lh effect when the effects from the vertical wind shear and beta drift are both taken into account this result is further supported by the diagnosis on storm motion based on potential vorticity tendency although important such feedback to typhoon track from rainfall asymmetry that is induced by the blocking effect of topography have not been reported or studied

a numerical study of the effect of island terrain on tropical cyclones abstract a triply nested movable mesh model was used to study the behavior of tropical cyclones encountering island mountain ranges the integration domain consisted of a 37 wide and 45 long channel with an innermost mesh resolution of 1 6 the storms used for this study were embedded in easterly flows of 5 and 10 m s 1 initially realistic distributions of island topography at 1 6 resolution were inserted into the model domain for the region of the caribbean including the islands of cuba hispaniola and puerto rico the island of taiwan and the region of luzon in the northern philippines it was found that the islands affected the basic flow as well as the wind field directly associated with the storm system the combination of these effects caused changes in the track and translational speed of the storm in particular in the case of the 5 m s 1 easterly flow the storm accelerated and veered to the north well before reaching taiwan for the other island distributions the northward deflecti

control of granite emplacement by regional deformation abstract a combination of structural measurements and gravity data is used to investigate the mode of granite emplacement in various tectonic settings the deepest zones revealed by gravity data provided those zones also show vertical lineations in outcrop are interpreted as magma feeder channels these structures or root zones reflect the flow pattern of the upwelling magma while being emplaced they can be interpreted within the regional stress field active during that time granites intruded during transcurrent shearing have only a few feeder channels these roots are not connected to the main shear zone all of them lie within locally extensional areas of the regional stress field this situation is also observed in granites emplaced during a compressional phase of deformation when emplaced during a regionally extensional phase the granitic plutons are very thin with many small deeper zones in which variously evolved granite types may be intrusive these regions vertically differentiated are also interpreted as feeder channels the different morphology at depth as well as the difference in the number of root zones suggest that deformation controls the emplacement of granitic plutons the root zones are oriented at a high angle to the direction of maximum compression when magma is emplaced in a plastic crust if the pluton is emplaced higher in a brittle crust then the roots are aligned with the maximum compression according to the andersonian theory of fracture the orientation of the root zone along the direction of extension in a plastic crust may be explained by shearing which acts as a valve mechanism for segregating magma in all the examples the geometry of the root zone relative to the major fault plane implies that the shear zone does not induce magma generation and that it does not serve as a guide for magma emplacement

development of the australian proterozoic crust as inferred from gravity and magnetic anomalies abstract gravity anomalies in australia have been used to map trends within basement blocks to map the margins of the blocks and to determine the relative ages of the blocks the inferred pattern of continental growth is consistent with that found by isotopic dating and from exposed geology the ages of cratonization of the total area of land basement are 18 archaean 53 proterozoic and 29 phanerozoic exposed basement generally has higher gravity variability than basement overlain by cover sediments the higher gravity variability is due to alternating bands of granite volcanics and the relative uplift and exposure is attributed to associated crustal underplating proterozoic crustal reworking takes several forms parts of archaean blocks were remobilized by extensive proterozoic metamorphism young blocks cratonized against older blocks caused reworking at least 50 km into the older blocks crustal rifts over 700 km long and 70 300 km wide were formed simple rifting resulted in crustal attenuation and sedimentation while more complex rifting resulted in the introduction of new igneous material and reworking of the older crustal material

warakurna large igneous province a new mesoproterozoic large igneous province in west central australia coeval mafic igneous rocks emplaced rapidly over 1 5 3 10 6 km 2 in western and central australia represent the erosional rem nants of a late mesoproterozoic large igneous province named here the warakurna large igneous province shrimp u pb dating of rocks separated by as much as 1500 km indicates that the main episode of magmatism occurred between 1078 and ca 1070 ma the warakurna large igneous province includes layered mafic ultramafic intrusions and mafic to felsic volcanic rocks and dikes in central australia a 1000 km long mafic sill province in western australia and several swarms of mafic dikes the large areal ex tent and short duration imply emplacement above a mantle plume head despite their wide separation the mafic rocks have similar mid oceanic ridge basalt normalized trace element patterns and rare earth element characteristics west directed paleocurrents westward radiating dike swarms and the occurrence of high mg rocks indicate that the center of the plume head was located be neath central australia other late mesoproterozoic large igneous provinces in the laurentia and kalahari cratons appear to be significantly older than the warakurna large igneous province in australia and thus are unlikely to be related to the same mantle plume head

on typhoon track deflections near the east coast of taiwan abstracttyphoons with deflection tracks dts within a 200 km distance of the mountainous island of taiwan are examined we analyze 84 landfalling typhoons that compose 49 dt cases turning to the left hand side including 18 with very large deflection angles da 20 and another 7 having looped tracks lts most of the large da and lt cases are northern landfall type reaching taiwan s east coast poleward of 24 n and originally possessing relatively slow translation speeds 4 m s 1 their average translation speeds however increase by 50 in the 3 h prior to landfall the wrf model is used to simulate dt cases and potential vorticity pv tendency diagnosis is used to interpret the contributions of the horizontal advection ha vertical advection va and diabatic heating dh terms the northern landfall tropical cyclones tcs possess significant cross mountain flow to the south of the storm near the coast resulting in vorticity stretching the va effect and subsidence warming the subsi

neoproterozoic stratigraphy of the centralian superbasin australia abstract the basement of central australia includes the arunta block and the 1200 1100 ma musgrave block succeeded by 1075 1000 ma bimodal volcanic rifts and dolerite dykes a regional hiatus at 1000 800 ma interpreted as reflecting a central post volcanic underplated upland was followed at 800 ma by a second swarm of dykes in the musgrave block gawler craton and stuart shelf associated with the crustal sagging that initiated the centralian superbasin the centralian superbasin is defined here to encompass the neoproterozoic fill of the amadeus georgina ngalia officer and savory basins the intra cratonic superbasin was disrupted internally 540 600 ma ago petermann ranges orogeny by a central uplift and associated thrusts and by mid carboniferous 320 ma tectonism alice springs orogeny to form the structural basins listed above the stratigraphy and sedimentology of the relatively well known areas can be used as a basis for predicting those of the poorly known regions new results from acritarch biostratigraphy and isotope chemostratigraphy in conjunction with conventional lithostratigraphy and sequence analysis allow better stratigraphic resolution than previously possible field observations in the recently discovered savory basin in western australia provide a basis for correlations with the adjacent basins

the influence of island topography on typhoon track deflection abstracthigh 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 deflec

the musgrave province stitching north west and south australia abstract the musgrave province in central australia is an east west trending 120 000 km2 region composed of lithologic units that range in age from earliest mesoproterozoic to neoproterozoic it is one of the few terrains in australia that records significant grenvillian aged tectonism and has a distinctly younger geological history than the surrounding fragments of proterozoic australia compared to other proterozoic terranes of australia the evolution of the musgrave province is poorly understood the region contains evidence for the development of earliest mesoproterozoic arc related magmatism with major juvenile crustal additions comprising intercalated felsic and mafic gneisses with protolith ages ranging from ca 1 60 to 1 54 ga this period of arc magmatism was followed by closure of the ocean separating the north australian craton nac from the south australian craton sac at ca 1 54 ga arc magmatism and collision was followed by a period of extension during which protoliths to the metasedimentary rocks of the eastern musgrave province were deposited at ca 1 4 ga the combined juvenile nd isotopic signature and detrital zircon ages from these metasediments suggests provenance from non australian sources with possible sources originating from laurentia granitic magmatic events occurred at ca 1 3 and 1 20 1 14 ga the latter comprising the voluminous a type granites of the pitjantjatjara supersuite the intrusion of these magmatic units provide key temporal constraints on deformational events and are coeval with the voluminous a type suites of laurentia which would invite correlation of australia with laurentia at ca 1 30 1 14 ga these magmatic episodes are accompanied by deformation at granulite facies at ca 1 30 ga unnamed event and 1 23 1 15 ga musgrave orogeny these deformation metamorphic events have completely recrystallised any primary layering within the pre 1 30 ga rocks forcing interpretations on their genesis to be inferred from geochemical and isotopic data the tectonic significance of these events is not clear however they may form part of a larger grenville aged deformational belt extending into the western australian albany fraser province and antarctica emplacement of the voluminous mafic ultramafic giles complex and associated granulite facies metamorphism of the giles event occurred at ca 1 078 ga the layered intrusions of the giles complex are generally fault bound and are considered to represent discrete bodies emplaced in an extensional regime associated with generation of the warakurna large igneous province the ca 1 08 ga alcurra dolerite unnamed ca 1 0 ga olivine dolerites and ca 0 8 ga amata dolerite dissect much of the musgrave province the alcurra dolerite and unnamed olivine dolerite dykes have been proposed as originating from a modified sub continental lithospheric mantle whereas the amata dolerite is proposed to be plume related coinciding with the initiation of rifting creating the centralian superbasin an earliest cambrian intraplate transpressional event is recorded in the ca 550 ma petermann orogeny this resulted in deep crustal exhumation of much of the northern musgrave province from beneath the centralian superbasin with mylonitic deformation recorded at pressures of 12 kbar and temperatures of 700 750 c

effects of landfall location and the approach angle of a cyclone vortex encountering a mesoscale mountain range abstractthe orographic effects of landfall location approach angle and their combination on track deflection during the passage of a cyclone vortex over a mesoscale mountain range are investigated using idealized model simulations for an elongated mesoscale mountain range the local vorticity generation driving the cyclone vortex track deflection is more dominated by vorticity advection upstream of the mountain range by vorticity stretching over the lee side and its immediate downstream area and by vorticity advection again far downstream of the mountain as it steers the vortex back to its original direction of movement the vorticity advection upstream of the mountain range is caused by the flow splitting associated with orographic blocking it is found that the ideally simulated cyclone vortex tracks compare reasonably well with observed tracks of typhoons over taiwan s central mountain range cmr in analyzing the relative vorticity budget the authors found that jumps in the vortex path are lar

a numerical study of the track deflection of supertyphoon haitang 2005 prior to its landfall in taiwan 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

on the geographic asymmetry of typhoon translation speed across the mountainous island of taiwan abstractthis paper examines the effect of topographically phase locked convection on the motion of typhoons across the island of taiwan data for 84 typhoons that reached taiwan s eastern coast from 1960 to 2010 are analyzed with motions compared to the long term average overland translation speed for 61 continuous track typhoons among all cases 77 of the slow moving tropical cyclones tcs made landfall on the northern end of taiwan s eastern coast while 60 of the fast storms had southeastern coastal landfalls this geographic asymmetry with respect to typhoon translation speeds widened after landfall as the slow movers typically decelerated during the overland period whereas the faster tcs sped up in particular the average overland duration was 16 h for the slow class compared to only 3 h for the fast moving typhoons the combination of slower translation with longer duration for the northern class of tcs led to large rainfall on the southwestern slope of the island s central mountain range we

controls on the locus of intraplate deformation in central australia abstract the locus of intraplate deformation in central australia changed from the presently preserved southern margin of the amadeus basin during the late neoproterozoic to early phanerozoic petermann orogeny to the northern margin in the late phanerozoic alice springs orogeny immediately prior to each event the thickness of the amadeus basin sediments varied from as little as 1 5 km in the central parts of the basin to as much as 7 km in the vicinity of the presently preserved margins of the basin with the locus of deformation mimicking the locus of maximum sedimentary thicknesses at the onset of each orogenic event as such these orogenies represent extreme examples of basin inversion a process observed in many intracratonic basins worldwide we show that differential burial of the central australian proterozoic basement complexes beneath the amadeus basin is capable of producing variations in moho temperature of up to 30 c prior to the petermann orogeny and up to 110 c prior to the alice springs orogeny for a brace goetze model of lithospheric rheology the variations in moho temperature equate to variations in effective lithospheric strain rate of 1 4 orders of magnitude implying that variations in thickness of the sedimentary blanket may have played a primary role in localising phanerozoic intraplate deformation in central australia an appealing aspect of this model lies in its corollary that the removal of the sedimentary blanket during denudation of the orogen will be accompanied by dramatic cooling and strengthening of the lithosphere this may provide a plausible explanation for the long term persistence of the extraordinary gravity anomalies 150 mgal developed during these central australian intraplate orogenies

constrained inversion of geologic surfaces pushing the boundaries during the past 10 years there has been a shift in modelling for geophysical interpretation away from idealized geometrical bodies floating in air and toward fully three dimensional representations this transition has been driven by a number of factors both technological and conceptual the principal conceptual driver has been the growing recognition of the importance of integrated interpretations interpretation is a shared responsibility of geoscientists the common goal being an earth model consistent with all available information

structural controls on proterozoic nickel and gold mineral systems identified from geodynamic modelling and geophysical interpretation east kimberley western australia abstract major structures considered important for controlling mineralisation in the halls creek orogen east kimberley are identified via integrated interpretation of geophysical and geological data combined with geodynamic numerical modelling in the numerical geodynamic models the second invariant of strain rate e ii is used to investigate the shearing processes that led to the development of major faults or shear zones and assessing their role as lithospheric scale conduits and pathways for the movement of magmatic and hydrothermal fluids into the upper crust the influence of these deep structures interpreted from the geodynamic models is evaluated through structural interpretation of geophysical remotely sensed and geological data when compared to the location of ni and au mineral deposits the deep crustal scale structures delineated in the models and compared to those mapped in the region contain a close spatial relationship with mineral deposits it is apparent that 1st order crustal scale structures acted as fluid conduits in the deep crust resulting in the formation of ni cu pge deposits and are associated with au mineralisation however 2nd and 3rd order structures manifesting in the upper crust as deformation focused mineralising fluids and magma resulting in the formation of gold deposits large scale structures developed early in the genesis of the halls creek orogen appear to be long lived and have been reactivated these form the margins of kimberley craton domains and influence the location of ni cu pge mineralisation whereas the lower order structures acted as structural traps for the subsequent deposition of au mineralisation

effects of moist froude number and cape on a conditionally unstable flow over a mesoscale mountain ridge abstract in this study idealized simulations are performed for a conditionally unstable flow over a two dimensional mountain ridge in order to investigate the propagation and types of cloud precipitation systems controlled by the unsaturated moist froude number fw and the convective available potential energy cape a two dimensional moist flow regime diagram based on fw and cape is proposed for a conditionally unstable flow passing over a two dimensional mesoscale mountain ridge the characteristics of these flow regimes are 1 regime i flow with an upstream propagating convective system and an early slowly moving convective system over the mountain 2 regime ii flow with a long lasting orographic convective system over the mountain peak upslope or lee slope 3 regime iii flow with an orographic convective or mixed convective and stratiform precipitation system over the mountain and a downstream propagating convective system and 4 regime iv flow with an orographic stratiform precipitatio

granite magma formation transport and emplacement in the earth s crust the origin of granites was once a question solely for petrologists and geochemists but in recent years a consensus has emerged that recognizes the essential role of deformation in the segregation transport and emplacement of silica rich melts in the continental crust accepted petrological models are being questioned either because they require unrealistic rheological behaviours of rocks and magmas or because they do not satisfactorily explain the available structural or geophysical data provided flow is continuous mechanical considerations suggest that far from being geologically sluggish granite magmatism is a rapid dynamic process operating at timescales of or 100 000 years irrespective of tectonic setting

geologically constrained gravity inversion for the voisey s bay ovoid deposit constructing a general three dimensional model of the subsurface density distribution by minimum structure or occam style inversion of gravity data has been practical now for several years the usual approach is to seek a model that is simple in the sense of having the least amount of spatial variation while still reproducing the observations hence the description minimum structure this has the advantage of generating models with few if any fictitious features however often the models produced bear only a gross diffuse resemblance to geology it has been recognized since the inception of the minimum structure inversion technique that geological information can be incorporated by seeking a model that is simple in the sense of being as close as possible to a reference model while still fitting the observations this is rarely done often because insufficient geological information is available or because inversion of geophysical data is no longer thought to be useful once a target has been fou

interaction of typhoons with the taiwan orography part i upstream track deflections abstract a combined observational and numerical modeling approach is used to study the upstream track deflections of westward moving tropical cyclones approaching the mountainous terrain of taiwan although the standard deviations are large the mean track deflections are larger and have a different orientation for storms approaching the southern end of the island from those approaching the northern end the deflections tend to be larger for weaker and slower moving storms two distinct regions of upstream track deflections that are detected in the observations are explored in a sensitivity study with a 45 km horizontal resolution and 16 layer numerical model as the outer circulation of the tropical cyclone begins to interact with the mountain barrier the zonal decelerations and southward track deflections are explained by an enhanced blocking and deflection of the environmental flow advecting the cyclone the larger effect for southern approaching storms compared to northern storms is because the stron

idealized simulations of the effect of taiwan topography on the tracks of tropical cyclones with different steering flow strengths this is the fourth part of a study on the effect of topography on tropical cyclone tc tracks in previous parts idealized simulations were conducted using the weather research and forecasting model to investigate the underlying mechanisms for the upstream deflection and the local and remote topography effect on tcs with different sizes none of these simulations included any background flow in this part uniform easterly steering flows of 5 and 10 m s 1 are introduced to study the track changes under such conditions lee vortices are generated downstream of the taiwan topography by the steering flow the tc terrain induced gyres found in the previous parts also develop when the tc circulation begins to interact with the topography and subsequently dominate over taiwan the cyclonic gyre merges with the cyclonic lee vortex induced by the steering flow and the anticyclonic gyre is advected cyclonically around the tc centre which later deflects the tc because the circulation at the outer radii of a tc competes with the steering flow a smaller tc under a stronger steering flow has to move closer to taiwan in order to generate such gyres this delayed generation of the gyres then leads to the delayed onset of the northward deflection for such a tc for a large tc the circulation at its southern part is weakened by the steering flow so that the track of the anticyclonic terrain induced gyre is changed which results in a larger track deflection of the tc

evolution of the mount woods inlier northern gawler craton southern australia an integrated structural and aeromagnetic analysis structural mapping integrated with interpretation and forward modelling of aeromagnetic data form complimentary and powerful tools for regional structural analysis because both techniques focus on architecture and overprinting relationships this approach is used to constrain the geometry and evolution of the sparsely exposed mount woods inlier in the northern gawler craton the mount woods inlier records a history of poly phase deformation high temperature metamorphism and syn and post orogenic magmatism between ca 1736 and 1584 ma the earliest deformation involved isoclinal folding and the development of bedding parallel and axial planar gneissic foliation s1 this was accompanied by high temperature upper amphibolite to granulite facies metamorphism at ca 1736 ma during subsequent north south shortening d2 open to isoclinal south southeast oriented f2 folds developed as the palaeoproterozoic successions of the inlier were thrust over the archaean nuclei of the gawler craton the syn d2 engenina adamellite was emplaced at ca 1692 ma the post d2 history involved shear zone development and localised folding exhumation of metamorphic rocks and deposition of clastic sediments prior to the emplacement of the ca 1584 ma granite balta suite the mount woods inlier is interpreted as the northern continuation of the kimban orogen

semiautomated quantification of the influence of data richness on confidence in the geologic interpretation of aeromagnetic maps abstractgeologic interpretations of aeromagnetic maps are highly subjective but are rarely accompanied by a quantitative confidence assessment which is a key limitation on the usefulness of the results here we outline a method with which the relative level of data richness can be assessed quantitatively leading to an improved understanding of spatial variations in interpretational confidence simple rules were used to quantify the likely influence of several major sources of uncertainty these were 1 the level of geologic constraint using the local abundance of outcropping rock and the quality of geologic mapping 2 the interpretability of the aeromagnetic data considering the strength of edge like features and the degree of directionality of these features a proxy for structural complexity 3 data collection and processing errors including gridding errors derived from the statistical error returned during kriging and the influence of anisotropic line data collection on the detection of g

multi scale integrated structural and aeromagnetic analysis to guide tectonic models an example from the eastern musgrave province central australia abstract in many polydeformed precambrian provinces the understanding of their tectonic history is limited by insufficient exposure which leads to difficulty in developing links between local and regional architecture and results in poorly constrained models of their regional scale architecture high resolution aeromagnetic data allows interpretation and modelling at a scale comparable to structural mapping and by integrating these methods these links can be developed with high confidence as an example we integrate structural mapping aeromagnetic data interpretation and 3d magnetic inversions in a multi scale structural analysis of the polydeformed eastern musgrave province in central australia deformation during the ca 1200 ma musgravian orogeny is characterised by an originally northeast trending structural grain defined by shear zones and tight to isoclinal folds at all scales 3d magnetic inversion models of syn to post musgravian granites indicate that this structural grain is predominantly west dipping this architecture suggests that a northeast oriented fold and thrust belt developed as a result of northwest southeast compression in central australia during the musgravian orogeny the next deformation event is characterised by an array of originally east southeast trending shear zones that truncate and offset the musgravian structural grain with apparent dextral displacements of up to 1 km these shear zones are commonly co located with mafic and granitic dykes suggesting a dilational origin and they are interpreted to have initiated under northeast southwest extension during the ca 1080 ma giles event the architecture of these two mesoproterozoic events was later extensively overprinted by two deformation events during the pan african aged ca 550 ma petermann orogeny the first is characterised by the widespread reactivation of mesoproterozoic structures resulting in a network of shear zones of variable orientation and the second is characterised by the development of crustal scale transpressional shear zones motion on which has caused the rotation of lithospheric blocks and the reorientation of prior structural trends by up to 90 collectively the architecture of these two events suggests broadly north south crustal shortening in central australia as an intraplate response to gondwana assembly this example demonstrates that the integration of structural geology with aeromagnetic interpretation and modelling can be used to develop high confidence links between local and regional structures these links permit the derivation of better constrained models of major tectonic events particularly in regions where outcrop is poor and the structural architecture is complex

a time and magnitude predictable model for generation of shallow earthquakes in the aegean area repeat times of strong shallow mainshocks have been determined by the use of instrumental and historical data for 68 seismogenic sources in the aegean and surrounding area 34 n 43 n 18 e 30 e for 49 of these sources at least two interevent times three mainshocks are available for each source by using the repeat times for these 49 sources the following relation has been determined log t t 0 36m min 0 35m p a wheret t is the repeat time measured in years m p the surface wave magnitude of the preceding mainshock mmin the magnitude of the smallest earthquake considered and a parameter which varies from source to source a multilinear correlation coefficient equal to 0 89 was determined for this relation

track deflection of typhoon nesat 2017 as realized by multiresolution simulations of a global model abstracttyphoon nesat 2017 headed west northwestward toward taiwan but took a relatively larger northward deflection about 300 km away and then a leftward deflection after landfall at northern ta

tectonic evolution of proterozoic australia proterozoic australia has long been interpreted as a single intact continent in which all tectonic and magmatic activity was intracratonic this paper proposes an alternative hypothesis in which numerous fragments of continental crust were assembled by plate tectonic processes the assembly was completed between 1300 and 1100 ma when the crustal fragments were combined as an early component of the rodinian supercontinent rifting and fragmentation of archaean continents began in the late archaean and continued into the proterozoic passive margin deposits such as those of the hamersley basin accumulated on isolated fragments of archaean crust these numerous fragments were subsequently assembled into three cratons by 1830 ma a west australian craton was established by collision of the archaean pilbara and yilgarn cratons which were joined along the capricorn orogen similarly a south australian craton developed by amalgamation of the proto gawler and proto curnamona cratons along the kimban orogen a north australian craton appears to have formed by accretion of numerous crustal fragments including the kimberley pine creek lucas and altjawarra cratons with sutures marked by the king leopold halls creek tennant creek and proto isan orogens the southern margin of the north australian craton was the site of repeated terrane accretion and orogenic activity between 1880 ma and 1400 ma this included an orogenic event at 1880 1850 ma the strangways 1780 1730 ma argilke 1680 1650 ma and chewings 1620 1580 ma orogenies and the intracratonic anmatjira uplift 1500 1400 ma intracratonic rifting at 1750 to 1710 ma and 1640 to 1600 ma produced the mcarthur basin and related minor basins parts of which were deformed by the isan orogeny at 1600 and 1530 ma rifting along the line of the capricorn orogen led to deposition in the overlying intracratonic bangemall basin between 1630 and 1300 ma along the eastern margin of the south australian craton the 1670 to 1600 ma olarian orogeny marks interaction with now obscured continental crust to the east tectonic activity between 1300 and 1100 ma led to the assembly of proterozoic australia as an early component of the supercontinent of rodinia this first involved the amalgamation of the west australian and north australian cratons followed by collision with the south australian craton the centralian superbasin developed over the junction of the north south and west australian cratons between 830 and 750 ma rifting to the east formed the adelaide geosyncline at 830 ma this was followed by the breakup of rodinia with the rifting apart of laurentia and gondwanaland along the eastern margin of proterozoic australia at 750 ma and the subsequent formation of the palaeo pacific ocean after the breakup of rodinia a series of northeast southwest compressional events followed by periods of relaxation reflect the assembly of a new supercontinent old lines of weakness were reactivated culminating in the intracratonic king leopold paterson petermann ranges and pinjarra orogenies between 620 and 540 ma subsequent reactivation continued into the phanerozoic with the widespread eruption of continental flood basalts and the formation of intracratonic basins 540 530 ma

orographic influence on a drifting cyclone abstract in this study a primitive equation numerical model is adopted to investigate the orographic influence on a drifting cyclone over an idealized topography similar to that of taiwan for a cyclone propagating from the east and impinging on the central portion of the mountain a northerly surface jet tends to form upstream of the mountain between the primary cyclone and the mountain due to blocking and channeling effects two pressure ridges and one trough are also produced when the cyclone approaches the mountain the low level vorticity and low pressure centers decelerate and turn southward upstream of the mountain due to orographic blocking at the same time the upstream low level vorticity is blocked by the mountain the abrupt increase of surface vorticity and the contraction of cyclone scale on the lee side are explained by the generation of new potential vorticity pv due to wave breaking associated with the severe downslope wind and hydraulic jump the generation of this new pv is evidenc

the influence of large scale topography on barotropic vortex motion abstract the motion of a barotropic vortex in the vicinity of a large scale topographic feature is examined through numerical integration of the shallow water equations in an equatorial beta plane channel the topographic parameters are chosen to represent the sierra madre mountains of mexico the motion of the vortex is affected through modification of the asymmetric circulation by vortex stretching associated with divergence of the horizontal velocity field as the air flows across the mountain a vortex that approaches the topography from the east is accelerated and deflected toward the south and a vortex initially west of the mountain recurves and moves toward the cut this motion is in contrast to the northwestward motion of a vortex over level terrain the vortex motion is also compared to the direction of the imposed potential vorticity gradient the topographic effects described in this paper may be important in forecasting hurricane motion in the eastern north pacific and western gulf of mexico

intraplate deformation in central australia the link between subsidence and fault reactivation abstract central australia has experienced two intraplate orogenic events involving significant north south shortening the late neoproterozoic to early cambrian petermann orogeny and the devonian to carboniferous alice springs orogeny in each event pre existing structures inherited from mesoproterozoic terrain amalgamation were reactivated and basement rocks exhumed from beneath thick sedimentary successions accumulated in the centralian superbasin the pattern of fault reactivation during these events shows a striking similarity to the pattern of subsidence in the overlying basin immediately prior to the petermann orogeny the centralian superbasin was thickest in the vicinity of the musgrave block the region in which deformation was subsequently localised at the same time crustal scale faults elsewhere in central australia that were covered by a relatively thin sheet of sediment remained inactive despite being favourably oriented to accommodate the north south shortening between the petermann and alice springs orogenies subsidence patterns shifted such that fault systems in the arunta block and also those in the southern musgrave block were buried by significant thicknesses of sediment whereas the major structures that were exhumed during the petermann orogeny were not significantly buried during the alice springs orogeny reactivation once again occurred along the most deeply buried faults even in the instances where those faults had remained inactive during the earlier petermann orogeny importantly the major petermann aged structures that were not buried during renewed subsidence remained inactive during the alice springs orogeny the record of reactivation implies that the presence of pre existing crustal scale faults alone was insufficient to localise deformation rather fault reactivation appears to have required a priming process that modulated the strength of the lithosphere on a regional scale the correspondence between the distribution of basement fault reactivation and subsidence patterns during both the petermann and alice springs orogenies implies a link between relatively thick sedimentation and long term lithospheric weakening we show that this link is compatible with the thermal effects of a thick sedimentary blanket in the context of central australia the mechanical impact of basin formation is likely to be enhanced by the presence of regionally elevated heat production in the proterozoic basement

cloud microphysics impact on hurricane track as revealed in idealized experiments analyses of tropical cyclones created in an idealized environment reveal how and why cloud microphysical assumptions can influencestorm motion including speed and direction it is well known that in the absence of a mean flow a leading factor in storm propagation is the establishment of beta gyres owing to planetary vorticity advection by the storm s circulation previous research demonstrated that tangential winds well beyond the core influence storm motion by helping to determine the gyres orientation and intensity microphysical assumptions especially involving average particle fall speeds can strongly influence the winds at outer radius more specifically microphysics modulates the radial distribution of column average virtual temperature which largely determines the radial surface pressure gradient and therefore the winds because they tend to be in gradient balance beyond the core microphysics schemes can differ markedly with respect to average fall speed depending on the complexity of the scheme and how interactions among condensation types are handled average fall speed controls the outward movement of particles produced in the eyewall into the anvil where they can influence the environment through cloud radiative interactions and phase changes with the assistance of some special sensitivity tests the influence of microphysics and fall speed on radial temperature gradients leading to different outer wind strengths and tracks is shown among other things this work demonstrates that the treatment of outer rainbands in operational models can potentially influence how simulated storms move thus affecting position forecasts

regional high pressure metamorphism during intracratonic deformation the petermann orogeny central australia the petermann orogeny is a late neoproterozoic to cambrian c 560 520 ma intracratonic event that affected the musgrave block and south western amadeus basin in central australia in the mann ranges within the central musgrave block mesoproterozoic granulite facies gneisses granites and mafic dykes have been substantially reworked by deep crustal non coaxial strain of late neoproterozoic to early cambrian age dolerite dykes have recrystallized to garnet granulite facies assemblages associated with the development of a mylonitic fabric at p 12 13 kbar and t 700 750 c migmatization is restricted to discrete shear zones which represent conduits for hydrous fluids during metamorphism peak metamorphism was followed by decompression to c 7 kbar reflecting exhumation of the terrane along the south dipping woodroffe thrust in scattered outcrops north of the mann ranges peak metamorphism occurred at p 9 10 kbar and t c 700 c the woodroffe thrust separates these deep crustal mylonites from granites that were metamorphosed during the petermann orogeny at p c 6 7 kbar and t c 650 c the similarity in peak temperatures at different crustal levels implies an unusual thermal regime during this event the existence of a relatively elevated geotherm corresponding with th and k enriched granites that were in the mid crust during the petermann orogeny suggests that radiogenic heat production may have substantially contributed to the thermal regime during metamorphism this potentially has implications for the mechanisms by which intra plate strain was localized during this event

high resolution aeromagnetic data over central australia assist grenville era 1300 1100 ma rodinia reconstructions 1 high resolution aeromagnetic data covering the polydeformed and poorly exposed musgrave province of australia reveals the grenville aged crustal architecture a combination of upward continuation and the potential field tilt filter out magnetic anomalies relating to a late neoproterozoic orogenic event and emphasize the more subtle magnetic structural grain formed during the ca 1320 1150 ma musgravian orogeny the resulting images indicate that crustal architecture is defined by the distribution of ca 1150 ma magnetic granitoids within less magnetic basement and is dominantly northeast trending continuous beneath the amadeus and officer basins and defines an orogenic belt that connects mesoproterozoic provinces the orogenic belt is truncated within australia and precludes a direct east trending connection between the musgrave province and contemporaneous orogens in laurentia clockwise rotation of the south australian craton and subsequent collision with the north and west australian cratons is our preferred model to explain the grenville aged architecture observed in australia

approximating edges of source bodies from magnetic or gravity anomalies cordell and grauch 1982 1985 discussed a technique to estimate the location of abrupt lateral changes in magnetization or mass density of upper crustal rocks the final step of their procedure is to identify maxima on a contoured map of horizontal gradient magnitudes we attempt to automate their final step our method begins with gridded magnetic or gravity anomaly data and produces a plan view of inferred boundaries of magnetic or gravity sources the method applies to both local surveys and to continent wide compilations of magnetic and gravity data e g zietz 1982 simpson et al 1983a kane et al 1982

zircon u pb chronometry of the pressure and temperature history of granulites in the musgrave ranges central australia ion microprobe u pb measurements of zircon in the musgrave ranges of central australia date the emplacement of a charnockite which is cut by a shear zone containing a garnet clinopyroxene assemblage m2 pt conditions 11 kb and 720 c at 1200 ma veinlets of a post m2 adamellite cut an m4 assemblage pt conditions 6 kb and 670 c contained in a metadolerite inclusion suggesting that the adamellite was emplaced during or after m4 igneous and metamorphic zircons in the adamellite however grew at about 1200 ma indicating that m2 and m4 were synchronous at the level of precision of our data the time interval between the growth of the two assemblages can not have been more than 20 ma we interpret the pressure temperature and time ptt path obtained by combining our thermobarometric data and zircon u pb ages in terms of magmatic heat input in a thickened crustal segment followed by rapid possibly technically driven uplift of the lower part of the thickened crust to a depth of 15 20 km

multiply deformed terrains problems of correlation abstract the best tools available for carrying out a structural analysis in a complex area are overprinting style and patterns of orientation unfortunately all have limitations which are reviewed briefly and discussed in areas of continuous unfaulted outcrop the deformational history can be established purely on the basis of overprinting but even in such areas there can be problems since not all overprinting relationships are unambiguous most fold interference patterns are reliable overprinting relationships based on foliations however are commonly unreliable and various examples are cited and discussed even in areas where the sequence of deformational events can be established their temporal significance is unclear since the methods applied only determine local relative timing and absolute relationships must vary in space and time across an orogen

aeromagnetic investigation of southern calabria and the messina straits italy tracking seismogenic sources of 1783 and 1908 earthquakes southern calabria and the ne corner of sicily italy were struck in 1783 and 1908 a d by two of the most catastrophic earthquakes ever in european history although it is generally acknowledged that the seisms were yielded by normal faults rupturing the upper crust of the calabria peloritani terrane no consensus exists on seismogenic source location and orientation here we report on a high resolution low altitude aeromagnetic survey of southern calabria and messina straits in southern calabria we document a broad weakly positive 5 10 nt anomaly zone interrupted by three en echelon sw ne null to negative magnetic anomaly corridors euler deconvolution and magnetic modeling show that the anomaly pattern is produced by a 1 1 5 km thick crustal layer located within 3 km depth this layer is offset by a 25 km long ne trending fault that corresponds to the armo normal fault recently inferred to be the source for the 1908 earthquake few kilometers to the south we also document a subparallel and previously unrecognized fault entering the messina straits and likely joining the armo fault at depth further east we model a 40 km long normal fault probably extending northeastward for additional 40 km running along the south calabria axis from aspromonte to the serre mountains and partly following the 18 km long surface rupture witnessed by deodat de dolomieu after the 1783 earthquake thus aeromagnetic data suggest that the sources of the 1783 and 1908 earthquakes are en echelon faults belonging to the same nw dipping normal fault system straddling the whole southern calabria

melting of a subduction modified continental lithospheric mantle evidence from late proterozoic mafic dike swarms in central australia geochemical and nd isotopic studies of two postorogenic late proterozoic 1083 23 ma high mg tholeiitec dike swarms in central australia indicate that the dike swarms were derived by partial melting of the continental lithospheric mantle which was modified by subduction processes during major crust formation events in the region both dike swarms stuart and kulgera which intrude the arunta and musgrave inliers respectively resemble island arc tholeiites in terms of geochemical features they yield whole rock sm nd ages of 1853 189 ma with nd 4 2 4 2 stuart and 1589 165 ma with nd 1 7 3 6 kulgera the two whole rock ages and initial nd values are remarkably similar to the oldest u pb zircon ages and initial nd values obtained from the corresponding basement blocks these isotopic data are interpreted as recording sm nd fractionation events in the continental lithospheric mantle associated with major episodes of crust formation in the early proterozoic

control parameters for the influence of a mesoscale mountain range on cyclone track continuity and deflection abstract in this study prospective control parameters are identified for diagnosing the continuity and deflection of cyclone tracks across a mesoscale mountain range based on idealized simulations of a westward moving cyclone it was found that the cyclone track becomes a discontinuous continuous track and the cyclone experiences more less deflection with a combination of small large values of vmax nh u nh r ly u flx and vmax fr and large small value of h lx the symbols are defined as follows vmax the maximum tangential wind n the brunt vaisala frequency h the mountain height u the basic wind speed r the radius of vmax f the coriolis parameter and lx and ly the horizontal scales of the mountain in x and y directions respectively a conceptual model is proposed to explain track deflection and continuity for a westward moving cyclone encountering idealized topography representative of the central mountain range of taiwan with weak orographic blocking a cyclone crosses over the mount

numerical study of convection observed during the winter monsoon experiment using a mesoscale two dimensional model abstract a two dimensional version of the pennsylvania state university mesoscale model has been applied to winter monsoon experiment data in order to simulate the diurnally occurring convection observed over the south china sea the domain includes a representation of part of borneo as well as the sea so that the model can simulate the initiation of convection also included in the model are parameterizations of mesoscale ice phase and moisture processes and longwave and shortwave radiation with a diurnal cycle this allows use of the model to test the relative importance of various heating mechanisms to the stratiform cloud deck which typically occupies several hundred kilometers of the domain frank and cohen s cumulus parameterization scheme is employed to represent vital unresolved vertical transports in the convective area the major conclusions are ice phase processes are important in determining the level of maximum large scale heating and vertical motion because there is a strong anvil componen