a numerical study of a mesoscale convective system over the taiwan strait on 7 june 1998 a mesoscale convective system mcs associated with a mesoscale cyclone was initiated on the south side of a mei yu front near hong kong and developed over the taiwan strait in this study numerical simulations for this event are performed using the fifth generation pennsylvania state university ncar mesoscale model mm5 the model captures the evolution of the mcs including the shapes of clouds and the rainfall rate in the mature phase of the simulated mcs the mcs is composed of several meso b and meso g scale convective clusters possessing commalike shapes similar to that of a midlatitude occluded cyclone the cluster at the head of the comma consists of convective clouds that are decaying while the tail of the comma is made up of a leading active convective line a mesoscale cyclone associated with a mesolow at the tailing region of the leading convective line is well developed below 500 hpa at 850 hpa a mesoscale low level jet mllj is located on the south side of the mesolow and is directed toward the comma shaped convective clusters at 300 hpa a mesohigh develops over the leading cluster a mesoscale upper level jet mulj is located on the east side of this mesohigh relative streamline and trajectory analyses show that the mllj associated with low ue and sinking air motion is a rear inflow jet while the mulj is the outflow jet of the mcs monsoon air from the boundary layer in front of the mcs feeds deep convection within the mcs momentum budget calculations are performed in the regions of the mllj and mulj at the developing and mature stage of the mcs the pressure gradient force and the horizontal advection are the main contributors to the development of mllj in the developing stage although the effects of the pressure gradient force are weakened considerably when the mcs reaches maturity the horizontal advection continues to accelerate the mllj vertical advection tends to decelerate the mllj both in its developing and mature stages the pressure gradient force and vertical advection are responsible for generating the mulj in the early stages and maintaining the mulj in its mature stage strong convective upward motion which carries the horizontal momentum upward from the exit of the mllj to the entrance of the mulj is crucial in the vertical coupling of the mllj and mulj

crustal large scale serpentinized mantle peridotite body in the sulu ultrahigh pressure metamorphic belt eastern china evidence from gravity and magnetic anomalies abstract from analysis of the geological and geophysical data gravity magnetic seismic and petrophysics we propose that geophysical anomalies are produced by a serpentinized mantle peridotite body smpb situated in the middle to lower crust in the sulu belt the smpb was formed by crustal emplacement of mantle peridotites accompanied by ultrahigh pressure uhp metamorphism our finding suggests an emplacement mechanism for the serpentinized mantle wedge smw early in the subduction process this is different from the classic view which holds that the serpentinized forearc mantle is formed by in situ hydration processes blakely et al 2005 the petrophysical properties of the smpb are similar to those of the serpentinized forearc mantle or smw in modern subduction zones worldwide but the formation mechanisms for smpb and smw are different this observation is important for understanding the geodynamic processes that operated in the large uhp metamorphic belt in the dabie sulu area eastern china

numerical simulations of tropical cyclone ocean interaction with a high resolution coupled model the tropical cyclone ocean interaction was investigated using a high resolution tropical cyclone ocean coupled model the model design consisted of the noaa geophysical fluid dynamics laboratory tropical cyclone prediction model which was coupled with a multilayer primitive equation ocean model coupling between the hurricane and the ocean models was carried out by passing into the ocean model the wind stress heat and moisture fluxes computed in the hurricane model the new sea surface temperature sst calculated by the ocean model was then used in the tropical cyclone model a set of idealized numerical experiments were performed in which a tropical cyclone vortex was embedded in both easterly and westerly basic flows of 2 5 5 and 7 5 m s 1 with a fourth experiment run with no basic flow specified initially the profile of the tangential wind for hurricane gloria at 1200 utc 22 september 1985 was used as the initial condition of the tropical cyclone for each of the experiments the model ocean was initially horizontally homogenous and quiescent to clarify the impact of the ocean response to the hurricane s behavior analogous experiments were also carried out with the sst kept constant control cases the experiments indicated that the cooling of the sea surface induced by the tropical cyclone resulted in a significant impact on the ultimate storm intensity due to the reduction of total heat flux directed into the tropical cyclone above the regions of decreased sst the sea surface cooling produced by the tropical cyclones was found to be larger when the storms moved slower in the experiments run without an initial basic flow the maximum sst anomaly was about 5 6 c with a resulting difference in the minimum sea level pressure and maximum surface winds of 16 4 hpa and 7 m s 1 respectively in contrast in the experiments run with the 7 5 m s 1 basic flow the maximum sst anomalies ranged from about 2 6 to 3 0 c with a difference in the minimum sea level pressure and maximum surface winds of about 7 3 hpa and 2 7 m s 1 the tropical cyclone ocean coupling significantly influenced the storm track only for the case with no basic flow and the 2 5 m s 1 easterly flow in these cases the storm with the ocean interaction turned more to the north and east no basic flow or the north 2 5 m s 1 easterly flow of the experiments with constant sst in the first case the storm by 72 hours was located over 70 km to the east southeast of the control case a possible explanation for this track deviation is related to a systematic weakening of the mean tangential flow at all radii of the storm due to the interaction with the ocean and resulting alteration of the beta drift

the role of radiogenic heat production in the thermal evolution of a proterozoic granulite facies orogenic belt eastern ghats indian shield abstract the eastern ghats belt egb is a deeply eroded proterozoic orogenic belt juxtaposed against the archaean dharwar bastar singhbhum cratons in the indian shield the tectono metamorphic history of this belt is broadly similar to the grenvillian orogenic belts the egb exposes dominantly the granulite facies rocks such as charnockites khondalites and migmatitic gneisses with less abundant intermediate to mafic granulites the granulites are intruded by small plutons of granites syenites and anorthosites the northern and southern parts of the belt negb and segb have distinct crustal histories but 1600 1000 550 ma old tectono metamorphic events are common to both the belts in this research we attempt to understand the present day and past thermal state of this orogen on the basis of our radioelement k u and th measurements at 562 sites using in situ gamma ray spectrometry with other geological and geophysical constraints the dominant rock types of the negb and segb have similar radioelement abundances 3 k 3 ppm u and 30 ppm th and heat production heat production of charnockites gneisses khondalites and intermediate granulites of the negb is 2 9 2 8 2 9 and 1 1 w m 3 respectively in the segb they are 2 7 2 5 2 8 and 0 6 w m 3 respectively and the mafic granulites are the lowest in heat production 0 3 w m 3 on the basis of the heat production data and crustal petrologic models we show that the crustal contribution of the negb and segb is 54 and 45 mw m 2 respectively which are broadly in good agreement with the available surface heat flow data thermal models of the present day egb crust indicate that the temperature at the moho is 550 c radioelements and heat production of the eastern ghats granulites are higher than the other granulite belts in the indian shield the crustal radiogenic heat contribution and moho temperatures of the egb are higher than the adjoining archaean cratons this could also be responsible for the development of inverted metamorphic isograds in the tectonic boundary between the egb and the adjoining cratons during a collisional orogenic event at about 550 ma ago

the role of cumulus convection in hurricanes and its representation in hurricane models this paper reviews our understanding of the role of cumulus convection in hurricanes as well as the various convective parameterization schemes that have been used in hurricane models elementary principles show that the primary tangential circulation of a vortex intensifies as rings of rotating air converge inward while conserving their absolute angular momentum thus intensification requires a mechanism to produce enough flow convergence above the surface boundary layer to counter the divergence induced there by the boundary layer itself typically such convergence is associated with the inward branch of the secondary circulation and is produced by an unbalanced negative radial gradient of buoyancy above the boundary layer resulting from condensational heating in the inner region of the vortex the fact that such buoyancy gradients are produced by all the parameterization schemes as well as by explicit schemes for latent heat release explains why all the models are able to simulate hurricane intensification with some degree of realism in a weak vortex the secondary circulation is dominated by buoyant forcing but as the vortex intensifies the contribution from surface friction increases until in the mature stage the buoyantly induced convergence must closely balance the frictionally induced divergence just above the boundary layer only a handful of the more recent hurricane models and only two of those in which convection is parameterized represent the effects of convective downdrafts these downdrafts cool and dry the subcloud layer tending to suppress further convection so that acting alone they would serve as a brake on hurricane intensification the strength of downdrafts decreases when the middle tropospheric relative humidity increases as a result of sustained cumulus convection over an area if surface wind speeds are high enough surface fluxes of sensible and latent heat can more than counteract the cooling and drying effects of convective downdrafts allowing continued warming of the troposphere in the inner region of the vortex so that vortex intensification can proceed accordingly the surface fluxes provide the energy source for the hurricane while convection transfers this energy vertically through the troposphere creating a suitable radial gradient of buoyancy to drive the secondary circulation of the vortex

palaeomagnetic constraints on the collision and rotation of north and south china the eastern half of china is dominated by the north china block ncb and south china block scb separated by a complex fold system that trends roughly east west interpretation of the geology of this fold belt has led to a variety of estimates of the age of amalgamation of these two blocks1 7 palaeomagnetic results are few and have also been subject to conflicting interpretations8 11 here we present our own palaeomagnetic results for late permian rocks for both the scb and ncb and summarize other relevant palaeomagnetic data by reinterpreting the polarity given in some previous studies we are able to synthesize the results for the widespread emeishan basalts of the scb and to suggest a new model for the collision and relative rotation of the two blocks

vorticity asymmetries in hurricane josephine 1984 a further analysis of omega dropwindsonde observations from three synoptic flow experiments in the environment of hurricane josephine is described complementing an earlier study by franklin the intensity structure and evolution of azimuthal wave number components of the 850 500 hpa layer mean and deep layer mean surface to 100 hpa vorticity fields including the symmetric component are investigated and the determination of the extent to which the asymmetries may be interpreted in terms of the barotropic theory of vortex motion in simple large scale environments is sought the latter endeavour calls for a necessarily arbitrary partitioning of the flow between vortex and environment as a starting point for this it is hypothesized that the environmental flow has a linear variation across a domain that appears to be encompassed by the storm circulation based on this assumption it is shown that on two of the three days on which data were available the structure and strength of the wave number 1 vorticity asymmetry were similar to the beta gyres that are a feature of model calculations the day to day changes in the orientation and strength of these asymmetries in the 850 500 hpa layer mean calculations are difficult to interpret in the light of barotropic theory and are possibly associated with vertical shear in the storm environment as described in a recent paper by jones such rapid changes are not seen in the corresponding deep layer mean calculations but the wave number 1 asymmetries in these fields are significantly influenced by the contributions from upper tropospheric levels where there are few data and where the vortex circulation centre is dispatched horizontally far from that at the surface the orientation of the wave number 2 asymmetry varied little over the three day observation period and was broadly consistent with the orientation of the large scale deformation field moreover its strength weakened during the period and varied monotonically with that of the deformation field a result that is consistent also with theoretical expectations the attempted analysis highlights certain intrinsic problems in interpreting hurricane motion in terms of current theories this is due partly to the non uniqueness of the partition required to separate the storm environment from the vortex asymmetries and partly because of the difficulty of determining a representative model equivalent value for the environmental absolute vorticity gradient from the data

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

ultrahigh pressure metamorphic rocks from the chinese continental scientific drilling project i petrology and geochemistry of the main hole 0 2 050 m the main hole mh of the chinese continental scientific drilling project ccsd in southern sulu has penetrated into an ultrahigh pressure uhp metamorphic rock slice which consists of orthogneiss paragneiss eclogite ultramafic rock and minor schist recovered eclogites have a uhp metamorphic mineral assemblage of garnet omphacite rutile phengite kyanite coesite epidote ultramafic rocks contain garnet olivine clinopyroxene orthopyroxene ti clinohumite phlogopite gneisses and schists contain an amphibolite facies paragenesis but their zircons have coesite garnet omphacite or jadeite and phengite inclusions indicating that eclogites and gneisses have been subjected to in situ uhp metamorphism using available geothermobarometers p t estimates of 3 1 4 4 gpa and 678 816 c for eclogites were obtained if surface outcrops and neighboring shallow drill holes are considered together we suggest that a huge supracrustal rock slab 50 km long 100 km wide 5 km deep was subducted to a depth 100 km and then exhumed to the surface the depth interval 0 2 050 m of the ccsd mh can be divided into six lithological units unit 1 consists of alternating layers of quartz rich and rutile rich eclogites with thin interlayers of gneiss and schist eclogites of unit 1 are characterized by nb ta sr and ti depletions low mg number and general lree enrichment unit 2 comprises rutile and ilmenite rich eclogite and minor normal eclogite and is characterized by high tio2 total fe v co and sr and very low sio2 alkali zr ba nb ta and total ree contents and lree depleted ree patterns with slightly positive eu anomalies unit 3 contains ultramafic rock and minor mgo rich eclogite protoliths of uhp rocks from units 1 2 and 3 represent a layered mafic to ultramafic intrusion at crustal depth units 4 and 6 consist of interlayered eclogite and paragneiss the eclogites are characterized by th u nb ta and ti depletion and k enrichment and lree enriched ree patterns paragneisses show nb ta sr and ti depletions and lree enriched ree patterns occasionally with slightly negative eu anomalies indicating that their protoliths represent metamorphic supracrustal series unit 5 consists mainly of orthogneisses showing distinct nb ta sr and ti depletions and lree enriched ree patterns with pronounced negative eu anomalies suggesting granitic protoliths in conclusion it is proposed that the southern sulu uhp belt consists of a series of meta supracrustal rocks a layered mafic ultramafic complex and granites

analytical and numerical studies of the beta effect in tropical cyclone motion part i zero mean flow abstract the effect on tropical cyclone motion is studied using an analytical as well as a numerical model in a nondivergent barotropic framework the analytical model and the linear version of the numerical model give essentially the same result the linear effect causes a westward stretching of the model vortex but no significant movement of the vortex center an east west asymmetry in the meridional wind field is also created it is the inclusion of the nonlinear term that produces the northwestward movement of the vortex previously found by other investigators e g kitade 1981 this northwestward movement increases with both the maximum wind speed and the radius of maximum wind in a constant shape vortex a wind maximum is also found to the northeast of the vortex which appears to be consistent with the observational findings of shea and gray this asymmetry plays an important role in the vortex motion

objective convective updraft identification and tracking part 1 structure and thermodynamics of convection in the rainband regions of two hurricane simulations to better understand the life cycles of convective elements in numerical model simulations a convective updraft tracking algorithm dubbed the statistical and programmable objective updraft tracker spout is developed spout identifies updraft cores in horizontal slices through a given model data set links these cores in three dimensions to form vertically coherent updrafts and then tracks updrafts in time via estimates of the mean local advection spout is evaluated in idealized hurricane simulations from both the regional atmospheric modeling system rams and weather research and forecasting wrf in both simulations spout indicates most updrafts live less than 60 min but some can persist for over 2 h updrafts are typically manifested as shallow cumulus cumulus congestus and deep cumulonimbus overall there is reasonable agreement between the vigor of convection and the amount of localized conditional convective instability also the majority of updrafts attain a tilted structure that is in accordance with the localized vertical wind shear nonetheless there are striking differences between models with the higher resolution wrf simulation producing around twice as many updrafts as rams moreover the wrf updrafts are significantly weaker this paper highlights the utility of spout for studying convective life cycles in high resolution numerical simulations and provides some basic features of convection in two hurricane simulations

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

adaptation of the near surface wind to the development of sand transport a model of wind blown sand transport is described with particular emphasis on the feedback between the grain cloud and the near surface wind the results from this model are used to develop owen s 1964 hypothesis that the grain layer behaves so far as the flow outside it is concerned as increased aerodynamic roughness whose height is proportional to the thickness of the layer the hypothesis is developed to show the influence this dynamic roughness has on the turbulent boundary layer above the saltation layer two processes are identified which influence the path of the system towards equilibrium the first is the feedback between the near surface wind and the grain cloud in which the quantity of sand transported is limited by the carrying capacity of the wind the second is due to the temporal development of an internal boundary layer in response to the additional roughness imposed on the flow above the grain layer by the grain cloud a similarity is noted between the temporal response of a turbulent boundary layer to sand transport and the spatial response of a turbulent boundary layer downstream of a step increase in surface roughness finally it is noted that the work may have important implications for transport rate prediction in unsteady winds

failed cyclogenetic evolution of a west african monsoon perturbation observed during amma sop 3 abstract the so called perturbation d was a nondeveloping west african disturbance observed near dakar senegal during special observing period sop 3 of the african monsoon multidisciplinary analysis amma in september 2006 its mesoscale environment is described with the dropsonde data obtained during flights on three successive days with the service des avions francais instrumentes pour la recherche en environnement falcon 20 aircraft processes involved in this evolution are studied qualitatively with ecmwf reanalyses and meteosat 9 images the evolution of perturbation d was the result of an interaction between processes at different scales such as the african easterly jet aej a midtropospheric african easterly wave aew a series of mesoscale convective systems the monsoon flow dry low to midlevel anticyclonic saharan air and a midlatitude upper level trough the interaction between these processes is further investigated through a numerical simulation conducted with the french nonhydro

geophysical profiling across the sulu ultra high pressure metamorphic belt eastern china abstract the largest ultra high pressure metamorphic uhpm belt in the world is located along the dabie sulu region which tectonically belongs to the east part of the central orogenic belt of china integrated geophysical investigations of using deep seismic reflection mt and geothermal observations have been carried out in the sulu area since 1997 the results of integrated interpretation suggest the existence of three features 1 a rift beneath the lianshui basin by the jiashan xionshui fault 2 a special crustal pattern called the magmatic multi arch structure occurs beneath the northern sulu uhpm zone and 3 a northwest dipping regional thrust crosses the sulu crust representing the intracontinental subduction of the yangtze craton beneath the sulu metamorphic belts after collision between the yangtze and sino korean cratons a magmatic multi arch structure consists of some arched reflectors that occur in both the lower and the upper crust where arched reflectors coincide with granitoid plutons the multi arch structures are common in eastern china where many mesozoic granitoid plutons of different scales occur the crustal structures in the sulu metamorphic belts resulted from intensive dynamic processes following the triassic collision between the yangtze and sino korean cratons the formation and exhumation of uhpm rocks followed the collision and then intracontinental subduction of the yangtze craton beneath the dabie sulu terranes took place in the early and middle jurassic in the late jurassic the sulu lithosphere turned to an extensional regime large scale granitic intrusions occurred in eastern china these likely resulted from lithospheric thinning and asthenospheric uplifting the granitic intrusions came to a climax during the cretaceous and were followed by rifting along existing faults in the early eogene resulting in many petroleum basins the granitoid emplacement that generated the magmatic multi arch structure and the rift were consequences of the lithospheric thinning process and deep intracontinental subduction of the yangtze craton beneath the sulu metamorphic belt might partially contribute to the lithospheric thinning

metamorphism and geochronology of granulites and migmatitic granulites from the magondi mobile belt zimbabwe the magondi mobile belt which crops out to the west of the zimbabwe archaean craton is an early to mid proterozoic feature within which sediments of the magondi supergroup were deformed and metamorphosed metamorphic grade increases northwards along the strike of the belt from greenschist facies in the south to granulite facies in the north the granulite facies rocks were partially melted during metamorphism at pressures of 5 7 kbar and temperatures of about 700 750 c with fluids buffered to low values of pfl late stages of partial melting were driven by vapour poor dehydration melting reactions an age for the metamorphism is indicated by rb sr ages of 1890 260 ma from enderbitic granulites at the rukomeshe river causeway east of makuti and of 1780 280 ma from garnet bearing and granitic granulites from the nyaodza region just east of lake kariba these ages confirm an early proterozoic age for the magondi orogeny which can be correlated with deformation in the kheis belt occupying a similar position on the western margin of the kaapvaal craton later brittle deformation and cataclasis distributed throughout the granulites but locally concentrated in n s striking shear zones are the result of deformation in the footwall of the south verging pan african thrust sheets

a heavy precipitation event in the yangtze river basin led by an eastward moving tibetan plateau cloud system in the summer of 2016

snowdrift modelling in a wind tunnel vertical and horizontal variation of the snow flux this paper deals with the influence of the vertical and horizontal varia tion of aeolian snow flux on estimations of snow storm duration and on snowdrift patterns simulated in a wind tunnel first of all we shall review recent developments including our own simulations con cerning the horizontal increase of mass flux until driftin g snow saturation has been reached next after a critical examination of various snowdrift modell ing criteria we present the results of an experiment undertaken in our wind tunnel we studied cross section drift area changes behind a small scale snow fence as a function of time for different fetches but for the same mean wind speed at the beginning of the testing sect ion for each fetch we carried out vertical profiles of sand particles using image processing and we studied the geometrical parameters of the drift we conclude that changes in the cross section drift area depend on the ablation length and if particle saturation is not reached the use of a storm duration scale leads to overevaluation of prototype storm duration moreover we point out that drift pattern vary as a function of the concentration profiles

relationships between the petrophysical properties density seismic velocity heat generation and mineralogical constitution the petrophysical properties density p compressional wave velocity v p and heat generation a exhibit considerable variation with rock type to characterize a given rock quantitatively a single parameter the cation fraction expressed by the k value has been found to be suited best 100 crystalline rocks have been sampled to cover the widest possible range in k value from silicic types like granophyres and granites through granodiorites tonalites diorites gabbros amphibolites hornblendites pyroxenites to ultrabasic rocks p k a and v p were determined experimentally the latter at 0 5 kbar 50 mpa the interrelations between these properties were established by regression analysis the relation k and v p k show a linear dependence whereas a k a and a v p follow exponential laws in a w m 3 12 20 230 5 k mole cm 3 in a 22 5 8 15 g cm 3 and in a 16 5 2 74 v p km s all correlation coefficients are better than 0 9

radiogenic heat production in the upper third of continental crust from ktb the heat production rate of continental crystalline rocks was determined from cores and drill cuttings recovered from depths up to 9 1 km in boreholes drilled by the continental deep drilling program of germany ktb the drilled rocks are mainly gneisses and metabasites based on a large amount of data the comparison of laboratory and in situ determinations by logging shows good agreement the loss of radioactive elements in drill cutting samples at the shaker tables was minimized by using a broad range of available fragment sizes the data reveal a clear lithological dependence of the heat production rate of the metamorphic rocks at ktb the lithologically caused variations of the heat production rate have a wavelength in the order of the drilled depth and therefore they cover up any decreasing trend if there is one below 6 km tectonic elements such as fault zones play also an important role in the observed vertical distribution despite the availability of data for the upper third of the crust models to predict temperatures for greater depths still contain uncertainties

applicability of large scale convection and condensation parameterization to meso γ scale hirlam a case study of a convective event abstract this paper presents a case study of a single cold air outbreak event with widespread convective precipitation over southern finland on 25 may 2001 the purpose of the study is to investigate the applicability of the convection and condensation scheme of the high resolution limited area model hirlam on meso scales the study concentrates on the issue of grid size dependent convection parameterization an explicit approach without the convection scheme is also examined at the same time the performance of an experimental nonhydrostatic version of hirlam is evaluated model simulations are conducted with three different horizontal grid spacings 11 5 6 and 2 8 km model results are compared to observed radar reflectivity data utilizing a radar simulation model which calculates radar reflectivities from three dimensional model output the best results are obtained using nonhydrostatic dynamics and a grid size dependent convection scheme with a 5 6 km grid interval however even the best conf

coesite bearing eclogite from the dabie mountains in central china coesite and coesite pseudomorphs are recognized in eclogite from the dabie mountains a collision zone between the sino korean and yangtze cratons in central china this third known occurrence of coesite in deep crustal rocks is within an archean gneiss terrane and is the first locality where coesite has been identified as an inclusion in both omphacite and garnet crystals at the same location coesite bearing eclogite is estimated to form at pressures of 28 kbar and temperatures from 600 to 710 c the dabie mountains eclogite underwent retrograde metamorphism to amphibolite facies after its formation the preservation of coesite in eclogite is found to be strongly controlled by the pressure temperature time path that coesite bearing eclogite followed during its uplift and retrograde metamorphism

initialization and simulation of a landfalling hurricane using a variational bogus data assimilation scheme abstract the bogus data assimilation bda scheme designed by zou and xiao to specify initial structures of tropical cyclones was tested further on the simulation of a landfalling hurricane hurricane fran 1996 the sensitivity of the simulated hurricane track and intensity to the specified radius of maximum wind of the bogus vortex the resolution of the bda assimilation model and the bogus variables specified in the bda are studied in addition the simulated hurricane structures are compared with the available observations including the surface wind analysis and the radar reflectivity captured onshore during fran s landfall the sensitivity study of the bda scheme showed that the simulations of the hurricane track and intensity were sensitive to the size of the specified bogus vortex hurricanes with a larger radius of maximum sea level pressure gradient are prone to a more westward propagation the larger the radius the weaker the predicted hurricane results of the hurricane initial structures an

on the consistency between dynamical and thermodynamic equations with prescribed vertical motion in an analytical tropical cyclone model in our earlier paper we presented an analytical model for intensifying tropical cyclones tcs in which the effects of all nonlinear terms in the horizontal momentum equations are retained this analytical model was obtained by prescribing the time evolution of the vertical motion in this paper we demonstrate that with the prescribed vertical motion the system of governing equations for geophysical flows can be separated into two subsystems one consisting of the horizontal momentum and continuity equations and the other including the vertical momentum and thermodynamical equations results show that the analytical solutions for the horizontal winds obtained from the first subsystem are consistent with the mass field in the second subsystem such as the thermal wind relationship in tcs furthermore we show that use of any functional form for the mean vertical motion will not affect our previous major conclusions about the different growth rates either between the secondary and primary circulations or between the inner and outer regions in tcs copyright 2010 royal meteorological society

tests of an ensemble kalman filter for mesoscale and regional scale data assimilation part i perfect model experiments abstract through observing system simulation experiments this two part study exploits the potential of using the ensemble kalman filter enkf for mesoscale and regional scale data assimilation part i focuses on the performance of the enkf under the perfect model assumption in which the truth simulation is produced with the same model and same initial uncertainties as those of the ensemble while part ii explores the impacts of model error and ensemble initiation on the filter performance in this first part the enkf is implemented in a nonhydrostatic mesoscale model the fifth generation pennsylvania state university ncar mesoscale model mm5 to assimilate simulated sounding and surface observations derived from simulations of the surprise snowstorm of january 2000 this is an explosive east coast cyclogenesis event with strong error growth at all scales as a result of interactions between convective meso and subsynoptic scale dynamics it is found that the enkf is very effective in keeping th

sensitivity of simulated tropical cyclone structure and intensity to horizontal resolution abstract the weather research and forecasting wrf model is used to test the sensitivity of simulations of hurricane ivan 2004 to changes in horizontal grid spacing for grid lengths from 8 to 1 km as resolution is increased minimum central pressure decreases significantly by 30 hpa from 8 to 1 km grid spacing although this increase in intensity is not uniform across similar reductions in grid spacing even when pressure fields are interpolated to a common grid this implies that the additional strengthening of the simulated tropical cyclone tc at higher resolution is not attributable to sampling but is due to changes in the representation of physical processes important to tc intensity the most apparent changes in simulated tc structure with resolution occur near a grid length of 4 km at 4 km grid spacing and below polygonal eyewall segments appear suggestive of breaking vortex rossby waves with sub 4 km grid lengths localized intense updraft cores within the eyewall are numerous and bo

impact of horizontal resolution and the advantages of the nested domains approach in the prediction of tropical cyclone intensification and movement received 14 december 2008 revised 16 february 2009 accepted 17 march 2009 published 4 june 2009 1 the prediction of the intensification and movement of the orissa super cyclone osc 1999 was studied using the national center for atmospheric research mm5 mesoscale atmospheric model a case study of the osc has been chosen as it is noted to be the most intense cyclone over the bay of bengal of this century experiments were made with a single domain 1d with two way interactive nested two domains 2d and with three domains 3d the model was integrated for 5 days and the model predicted intensity and track positions were compared with observations results indicate that the enhancement of resolution produces higher intensity and does not influence the track of the storm the nested 2d and 3d experiments produce cyclone track closely agreeing with the observations while the 1d experiments show the deviation of the track toward north and northeast after 48 h thus with increasing errors differences in the simulations with single and nested domains indicate that simulated atmospheric circulation on the eastern parts of the domain contribute to the deviation of the track in the 1d experimentandthesuccessfulsimulationwith2dand3dexperimentsisduetothetwo way interactive approach of the nested domains

a heat generation model for continental crust based on deep drilling in the baltic shield abstract this paper presents a heat generation model for the old continental crust on the basis of a new petrological model on the origin evolution and deep structure of the crust in which petrological geochemical and geophysical data obtained from the kola superdeep borehole and other deep boreholes drilled into the crystalline basement of the east european platform are taken into account the petrological section obtained from the borehole observations was extrapolated down to the moho boundary taking into consideration the evolution and generalized seismic model of the continental crust in our model the continental crust is subdivided into three layers a granite gneiss layer 0 17 km a charnokite enderbite layer 17 30 km and a basic layer including autochthonous restites of the protocrust 30 40 km the boundaries between the layers correspond to seismic surfaces k1 and k2 the crustal contribution to heat flow is estimated to be about 25 mw m2 52 of the total heat flow for the baltic shield and the mantle heat flow is 22 24 mw m2 a comparison is made between the heat generation model obtained in this study and the ones estimated from seismic velocity structure the difference in the heat generation value between these models may originate from the differing geological and tectonic history of the sampling localities

the national meteorological center s quasi lagrangian model for hurricane prediction abstract a description is presented of the national meteorological center s quasi lagrangian model qlm which is used for operational hurricane prediction the model uses the primitive equations with high horizontal and vertical resolution and includes parameterizations of principal physical and dynamical processes that affect the motion and development of a hurricane because a storm s circulation is not well analyzed operationally due to a lack of observations a procedure was developed to insert an idealized vortex into the initial analysis the geopotential height and wind fields in the vortex satisfy the gradient wind relation with variable coriolis parameter and its structure depends on the size and intensity of the observed storm the primary purpose of the qlm is to provide numerical guidance for forecasting hurricane track considerable improvement in the track and the structure of a storm is obtained through the use of the idealized vortex further improvement in forecasts is attained with

fluids in deeply subducted continental crust petrology mineral chemistry and fluid inclusion of uhp metamorphic veins from the sulu orogen eastern china abstract the complex vein associations hosted in southern sulu ultrahigh pressure uhp eclogites contain quartz omphacite or jadeite kyanite allanite zoisite rutile garnet these minerals have chemical compositions similar to those of host eclogites inclusions of polycrystalline quartz pseudomorphs after coesite were identified in vein allanite and garnet and coesite inclusions were found in vein zircon these facts suggest that the veins together with host eclogites have been subjected to synchronous uhp metamorphism the vein minerals contain relatively high concentrations of rare earth elements ree high field strength elements hfse and transition metal elements tme a kyanite quartz vein has a whole rock composition similar to adjacent uhp metamorphic granitic gneisses abundant primary multi solid fluid inclusions trapped within uhp vein minerals contain complex daughter minerals of muscovite calcite anhydrite magnetite pyrite apatite celestite and liquid and gas phase of h 2 o with solids up to 30 70 of the inclusion volume the presence of daughter minerals anhydrite and magnetite indicates the subduction fluids were oxidizing and provides a possible interpretation for the high oxygen fugacity of subduction zone magmas these characteristics imply that the uhp vein minerals were crystallized from supercritical silicate rich aqueous fluids that were in equilibrium with peak uhp minerals and that the fluids in deeply subducted continental crust may contain very high concentrations of silicate as well as hree hfse and tme such fluids might have resulted in major fractionation between nb and ta i e the uhp fluids have subchondritic nb ta values whereas the host eclogites after extraction of the fluids have suprachondritic nb ta values therefore voluminous residual eclogites with high nb ta ratios may be the complementary suprachondritic reservoir capable of balancing the subchondritic depleted mantle and continental crust reservoirs

diagnosing forecast errors in tropical cyclone motion abstractthis paper reports on the development of a diagnostic approach that can be used to examine the sources of numerical model forecast error that contribute to degraded tropical cyclone tc motion forecasts tropical cyclone motion forecasts depend upon skillful prediction of the environment wind field and by extension the synoptic scale weather systems nearby the tc while previous research suggests that the deep layer mean dlm steering flow typically approximates the actual tc motion it is shown that the motion of even mature tcs can depart from the dlm steering flow an optimal environmental steering flow is defined which varies the vertical extent of the steering layer and the radius over which tc vorticity and divergence are removed errors in predicted tc motion are quantified using a diagnostic equation that accounts for not only differences in the synoptic scale flow but also differences in the depth and radius used to define the steering flow differences in the latter two parameters a

geochronology and geochemistry of leucosomes in the north dabie terrane east china implication for post uhpm crustal melting during exhumation migmatites are widespread in the north dabie ultrahigh pressure metamorphic terrane ndt of dabie orogen east china idiomorphic and poikilitic amphibole grains in both leucosome and melanosome contain inclusions of plagioclase quartz and biotite suggesting formation of leucosome by fluid present melting of biotite plagioclase quartz bearing protoliths at p 5 7 kbar t 700 800 c precise sims zircon u pb dating indicates that migmatization of dabie orogen initiated at 140 ma and lasted for 10 ma coeval with the formation of low mg adakitic intrusions in dabie orogen based on mineralogical petrographic and geochemical data leucosomes in ndt can be subdivided into three groups 1 high la yb n medium sr y group group i whose high dy yb n but medium sr y ratios are caused by amphibole and plagioclase residual during partial melting of dioritic to granodioritic gneisses 2 low la yb n low sr y group group ii whose flat hree patterns are produced by entrainment of peritectic amphiboles into melts derived from partial melting of dioritic gneiss 3 high la yb n high sr y and eu group group iii whose extremely high sr and eu but low other ree concentrations are caused by accumulation of plagioclase and quartz although group i and iii fall in the adakitic fields on la yb n yb n and sr y y diagrams they are chemically distinct from contemporary high pressure adakitic intrusions in dabie orogen in a series of geochemical indexes for example lower dy yb n and or sr y ratios at given la yb n ratio lower sr cao ratios lower rb concentration but higher k rb ratios therefore leucosomes are produced by anatexis of the exhumed ultrahigh pressure metamorphic rocks at middle crustal level instead of partial melting of thickened lower crust with garnet rich and plagioclase poor residual the coeval occurrence of migmatites and high pressure adakitic intrusions in dabie orogen indicates large scale partial melting of middle to thickened lower crustal column in the early cretaceous the required heat source may be the mantle heat conducting through the lithospheric mantle whose lower parts have been convectively removed

geothermal modelling of the lithosphere in the central baltic shield and its southern slope lithospheric temperature and heat flow density hfd were studied in the central baltic fennoscandian shield and its subsurface continuation to the south along a transect trending from eastern finland to southern estonia the transect represents an example of a low hfd 30 mw m 2 archaean craton on a thick 150 190 km lithosphere surrounded by early and middle proterozoic mobile belts on a thinner 110 150 km lithosphere with slightly elevated hfd 35 55 mw m 2 numerical 2 d conductive models were constructed in which peridotite solidus temperatures were assigned to those depths which correspond to the seismically determined lithosphere asthenosphere boundary this technique was found to reduce the effect of uncertainties in heat production and thermal conductivity values on the simulation results upper crustal heat production values for the finnish terrain were taken from published geochemical analyses of outcropping rocks for the estonian terrain new heat production values were measured from core samples representing nineteen deep boreholes middle and lower crustal lithologies were estimated with the aid of the deep seismic vpvs data and corresponding heat production values were adapted from global xenolith averages and from data for granulites cropping out in other precambrian areas the results of the modelling suggest that the lithosphere and moho depth variations are only weakly reflected in the measured surface heat flow data which are mainly controlled by heat sources in the upper crust the simulated heat flow densities at 50 km depth approximately at the moho are relatively low and range from 12 mw m 2 at the archaean northeastern end to 19 mw m 2 on the proterozoic southwestern end of the transect simulated temperatures at 50 km depth increase from northeast to southwest ranging from 450 550 c in eastern finland to about 650 c in estonia sensitivity of the simulations to parameter changes was studied by varying the heat production and thermal conductivity values the extreme values for the moho temperature estimates thus obtained may be about 50 k lower or 100 k higher than the values above the corresponding sensitivity of the moho hfd is about 6 mw m 2 and of the surface hfd 5 20 mw m 2 respectively

determination of the crustal and thermal structure of the erzurum horasan pasinler basins eastern turkiye using gravity and magnetic data the erzurum horasan pasinler basin which surrounds miocene rocks is oriented approximately e w and is located in eastern anatolia turkiye east anatolia where ophiolitic and young volcanic rocks are widespread is situated in the alpine himalayan fold thrust fault belt the nw se trending north anatolian transform fault zone and the ne sw trending east anatolian transform fault zone formed by the compressional regime of east anatolia control the main tectonics of the study region while the moho and conrad depths of the study region are 43 0 and 20 9 km respectively the average sedimentary thickness has been determined to be 5 2 km by using the power spectrum method on the other hand it is found that the depth of the moho in the region varies from 41 0 to 44 5 km and the depth of the conrad discontinuity varies between 22 and 26 km as computed using empirical equations the basement of the sedimentary layer is calculated to be 6 km by using inversion results applied to the residual gravity data the curie point depth and average heat flow value in this region are calculated as 18 0 km and 89 1 m wm 2 respectively geotherm calculations reveal that the moho temperature is 1 028 0 c based on the crustal model the high heat flow values obtained are attributed to tectonic activities and melting of the lithospheric mantle caused by upwelling of the asthenosphere

tropical cyclone initialization with a spherical high order filter and an idealized three dimensional bogus vortex abstract a tropical cyclone initialization method with an idealized three dimensional bogus vortex of an analytic empirical formula is presented for the track and intensity prediction the procedure in the new method consists of four steps the separation of the disturbance from the analysis determination of the tropical cyclone domain generation of symmetric bogus vortex and merging of it with the analysis data when separating the disturbance field an efficient spherical high order filter with the double fourier series is used whose cutoff scale can be adjusted with ease to the horizontal scale of the tropical cyclone of interest the tropical cyclone domain is determined from the streamfunction field instead of the velocities the axisymmetric vortex to replace the poorly resolved tropical cyclone in the analysis is designed in terms of analytic empirical functions with a careful treatment of the upper layer flows as well as the secondary circulations the geopotential of the vortex is given in suc

parameterization of convective precipitation in mesoscale numerical models a critical review abstract current approaches for incorporating cumulus convection into mesoscale numerical models are divided into three groups the traditional approach utilizes cumulus parameterization at convectively unstable points and explicit nonparameterized condensation at convectively stable points the fully explicit approach uses explicit methods regardless of stability the hybrid approach parameterizes convective scale updrafts and downdrafts but detrains a fraction of parameterized cloud and precipitation particles to the grid scale this allows the path and phase changes of such particles to be explicitly predicted over subsequent time steps the traditional approach provides the only alternative for numerical models with grid spacing too large to resolve mesoscale structure as grid spacing falls below 50 km the traditional approach becomes increasingly likely to violate fundamental scale separation requirements of parameterization particularly if mesoscale organization of convection is parameterize

subkilometer simulation of a torrential rain producing mesoscale convective system in east china part i model verification and convective organization abstracta nocturnal torrential rain producing mesoscale convective system mcs occurring during the mei yu season of july 2003 in east china is studied using conventional observations surface mesoanalysis satellite and radar data and a 24 h multinested model simulation with the finest grid spacing of 444 m observational analyses reveal the presence of several larger scale conditions that were favorable for the development of the mcs including mei yu frontal lifting moderate cold advection aloft and a moist monsoonal flow below and an elongated old cold dome left behind by a previously dissipated mcs results show that the model could reproduce the evolution of the dissipating mcs and its associated cold outflows the triggering of three separate convective storms over the remnant cold dome and the subsequent organization into a large mcs and the convective generation of an intense surface meso high and meso scale radar reflectivity morphologies in particular the model reproduces the passage of

monsoonal influence on typhoon morakot 2009 part i observational analysis abstracttyphoon morakot made landfall on taiwan with a record rainfall of 3031 5 mm during 6 13 august 2009 while previous studies have emphasized the influence of southwesterly winds associated with intraseasonal oscillations and monsoon surges on moisture supply the interaction between morakot and low frequency monsoon flows and the resulting influence on the slow movement and asymmetric precipitation structure of the typhoon were examined observationally embedded in multi time scale monsoonal flows morakot generally moved westward prior to its landfall on taiwan and underwent a coalescence process first with a cyclonic gyre on the quasi biweekly oscillation time scale and then with a cyclonic gyre on the madden julian oscillation time scale the coalescence enhanced the synoptic scale southwesterly winds of morakot and thus decreased its westward movement and turned the track northward leading to an unusually long residence time in the vicinity of taiwan the resulting slow movement and collocation

numerical modeling of blowing and drifting snow in alpine terrain in mountainous regions snow transport due to wind significantly influences snow distribution and as a result avalanche danger a physically based numerical two layer model is developed to simulate blowing and drifting snow in alpine terrain one layer describes the driving wind field and the transport in suspension the description is based on the atmospheric boundary layer equations using an e model for the turbulent closure the second layer describes the transport due to saltation including erosion and deposition of snow here conservation equations for mass and momentum are formulated for the mixture of snow and air particle trajectory calculations are used to parameterize quantities characterizing the saltation layer both layers are mutually coupled by boundary conditions a two way coupling between particles and airflow is taken into account comparisons between simulation results and field measurements around an alpine crest show encouraging results

new geothermal data from the kola superdeep well sg 3 abstract the kola superdeep well sg 3 reaches a depth of 12 262 m this provides the opportunity to obtain experimental data on thermal properties of deep horizons since 1985 a 8578 m deep borehole with a casing depth of 8278 m has been used as a geolaboratory the determination of the equilibrium temperature gradient and heat flow density hfd is more reliable than as published before to estimate hfd we used measurements of thermal conductivity from more than 8000 core samples below 4000 m rocks schists amphibolites gneisses and plagiogranites are characterized by significant anisotropy 1 17 2 10 this was taken into account when estimating the conductive hfd new experimental data on hfd in the interval of 0 4 0 9 km are in good agreement with previous results from 470 to 1675 m deep holes drilled near the sg 3 the 0 9 2 0 km interval shows abrupt increase in hfd up to an average value of 57 mw m 2 which differs significantly from the previously reported values of hfd from sg 3 from 37 to 44 mw m 2 as reported by different researchers the average hfd value of 63 mw m 2 in the 5 2 7 5 km interval is 17 43 higher than the previously estimated values within the depth interval from 7 6 to 8 2 km hfd shows a gradual decrease from 62 to 51 mw m 2 positive correlation between 1 and is observed only in the intervals of 2 5 4 3 km and 5 0 6 5 km as can be expected for a stationary conductive thermal regime analysis of the temporal variations of during the return of the hole to thermal equilibrium after its completion reveals that this parameter is capable of characterizing the permeability of a rock massif from the analyses of temporal variations of a lower permeability can be attributed to the part of the massif lying in the 3 0 4 5 km depth range it is proposed that the observed vertical variations in hfd are due to movement of fluids in the massif in some cases resulting in non stationary fields in particular the largest geothermal anomaly at 0 2 km depth is caused by a downward movement of meteoric waters in the zone of active water exchange the experimental results can be understood quantitatively if a permeability of 1 to 3 10 13 m 2 over a 1 2 km zone of exogenic fracturing is assumed an abrupt change of conductive hfd in the depth interval 1 7 2 2 km is attributed to a downward movement of fluids of 2 3 cm yr along inclined zones of fracturing at the boundary between igneous and sedimentary sequences this movement of fluids might be caused by a post glacial uplift of the baltic shield and would continue as lateral pressure in deep faults decreases

nested model simulation of moist convection the impact of coarse grid parameterized convection on fine grid resolved convection future generation operational weather prediction systems will likely include storm scale limited area models that will explicitly resolve convective precipitation however the high resolution convection resolving grids will need to be embedded or nested within coarser resolution grids that will provide lateral boundary conditions it is the purpose of this study to illustrate how the convective environment on a convection resolving stormscale model grid and therefore the convection itself can be significantly influenced by the treatment of convection on the coarser grids within which the fine grid is embedded it was confirmed that as in the actual atmosphere mass field adjustments resulting from convection in one area the outer grids in this case affect the convection in other areas the inner convection resolving grid that is the errors in precipitation timing precipitation intensity and the vertical distribution of latent heating associated with the treatment of convection on the outer grids greatly affect the explicit convection on the inner grid in this case the different precipitation parameterizations on the outer two grids produce up to a factor of 3 difference in the 24 h amount of explicit rainfall simulated on the inner grid even when the parameterization is limited to only the outer grid with explicit precipitation on both the middle and inner grids over a factor of 2 difference in 24 h total explicit rainfall is produced on the inner grid the different precipitation parameterizations on the outer grids appear to differently modulate the intensity and the timing of the explicit convection on the inner grid through induced subsidence

the march 1993 superstorm cyclogenesis incipient phase synoptic and convective scale flow interaction and model performance abstract the incipient stages of the 12 14 march 1993 superstorm ss93 cyclogenesis over the gulf of mexico are examined noteworthy aspects of ss93 include 1 it is the deepest extratropical cyclone ever observed over the gulf of mexico during the 1957 96 period and 2 existing operational prediction models performed poorly in simulating the incipient cyclogenesis over the northwestern gulf of mexico a dynamic tropopause dt analysis shows that ss93 is triggered by a potent potential vorticity pv anomaly as it crosses extreme northern mexico and approaches the gulf of mexico the low level environment over the western gulf of mexico is warmed moistened and destabilized by a persistent southerly flow ahead of the approaching pv anomaly ascent and a lowering of the dt associated with a lowering of the potential temperature ahead of the pv anomaly contributes to further destabilization that is realized in the form of a massive convective outbreak an examination of the national centers for envi

the multiple vortex structure of the el reno oklahoma tornado on 31 may 2013 abstractthis study documents the formation and evolution of secondary vortices associated within a large violent tornado in oklahoma based on data from a close range mobile polarimetric rapid s

studies on the initialization and simulation of a mature hurricane using a variational bogus data assimilation scheme abstract a bogus data assimilation bda scheme is presented and used to generate the initial structure of a tropical cyclone for hurricane prediction it was tested on hurricane felix 1995 in the atlantic ocean during its mature stage the pennsylvania state university national center for atmospheric research nonhydrostatic mesoscale model version 5 was used for both the data assimilation and prediction it was found that a dynamically and physically consistent initial condition describing the dynamic and thermodynamic structure of a hurricane vortex can be generated by fitting the forecast model to a specified bogus surface low based on a few observed and estimated parameters through forecast model constraint bda is able to recover many of the structural features of a mature hurricane including a warm core vortex with winds swirling in and out of the vortex center in the lower and upper troposphere respectively the eyewall the saturated ascent around the eye and descent or weak ascent in the eye

evaluation of bogus vortex techniques with four dimensional variational data assimilation abstract the effectiveness of a four dimensional variational data assimilation 4dvar technique for creating bogus vortices in numerical simulations of hurricanes is evaluated in this study a series of numerical experiments is conducted to generate initial vortices for hurricane georges and bonnie 1998 in the atlantic ocean by assimilating bogus sea level pressure and wind information into a mesoscale numerical model mm5 several different strategies are tested for investigating the sensitivity of the initial vortex representation to the type of bogus information while some of the results in this study confirm conclusions made in previous studies some significant differences are obtained regarding the role of bogus wind data in creating a realistic bogus vortex in contrast with previous studies in which the bogus wind data had only a marginal impact on creating a realistic hurricane this study concludes that the wind information is very important because 1 with assimilation of only bogus sea

thermal evolution of the upper yangtze craton secular cooling and short lived thermal perturbations abstract the upper yangtze craton uyc has stayed in a long term stabilization state its thermal history can be portioned into two parts secular evolutionary trend and short lived thermal perturbations the former is simulated by a two dimensional forward transient thermal model and the latter is discussed by reviewing previous studies the numerical modeling indicates the uyc tended to be cooling as it adjusted to the asynchronous rates of change in the internal radiogenic heat production and in the convecting mantle temperature below the cratonic root the average cooling rate of the uyc has been 58 c ga since the end of archean faster than that of the convecting mantle the surface heat flow presents a decreasing trend from 82 mw m2 at 2 5 ga to 53 mw m2 at present day which constructs the long term evolutionary path the thermal perturbations derived from the occasional tectono thermal events such as mantle plume activity and regional lithosphere extension serves as paroxysmal factors the thermal effects of the emeishan mantle plume were very strong yielding to the maximum heat flow anomaly of 100 mw m2 at the late permian in contrast the influences of regional lithosphere extension during both the early paleozoic period and the early permian middle triassic period were rather weak resulting in a surface heat flow increase of

some aspects of vortex structure related to tropical cyclone motion abstract some effect of tropical cyclone structure on the vortex motion are examined in a nondivergent barotropic numerical model with no basic current as suggested earlier by demaria the initial maximum wind speed has little effect on the track vortex translation associated with the beta effect depends sensitively on the strength of the flow between 300 and 1000 km from the center if the flow in this annulus is made more cyclonic the track will turn cyclonically and move more toward the west in the northern hemisphere the dynamics of this beta drift is studied via a decomposition into symmetric and asymmetric circulations the symmetric flow experiences a slight weakening of the maximum wind speed and an anticyclonic circulation is induced beyond 600 km the asymmetric circulation is dominated by an azimuthal wavenumber one circulation with an anticyclonic gyre east of the center a cyclonic gyre to the west and a nearly uniform broad scale ventilation flow between the gyres the vortex translati

numerical simulation of andhra severe cyclone 2003 model sensitivity to the boundary layer and convection parameterization the andhra severe cyclonic storm 2003 is simulated to study its evolution structure intensity and movement using the penn state ncar non hydrostatic mesoscale atmospheric model mm5 the model is used with three interactive nested domains at 81 27 and 9 km resolutions covering the bay of bengal and adjoining indian peninsula the performance of the planetary boundary layer pbl and convective parameterization on the simulated features of the cyclone is studied by conducting sensitivity experiments results indicate that while the boundary layer processes play a significant role in determining both the intensity and movement the convective processes especially control the movement of the model storm the mellor yamada scheme is found to yield the most intensive cyclone while the combination of mellor yamada my pbl and kain fritsch 2 kf2 convection schemes gives the most intensive storm the mrf pbl with kf2 convection scheme produces the best simulation in terms of intensity and track results of the simulation with the combination of mrf scheme for pbl and kf2 for convection show the evolution and major features of a mature tropical storm the model has very nearly simulated the intensity of the storm though slightly overpredicted simulated core vertical temperature structure winds at different heights vertical winds in and around the core vorticity and divergence fields at the lower and upper levels all support the characteristics of a mature storm the model storm has moved towards the west of the observed track during the development phase although the location of the storm in the initial and final phases agreed with the observations the simulated rainfall distribution associated with the storm agreed reasonably with observations

a lagrangian perspective on parameterizing deep convection abstractthe parameterization of deep moist convection as a subgrid scale process in numerical models of the atmosphere is required at resolutions that extend well into the convective gray zone t

one dimensional thermal modeling of the eastern pontides orogenic belt ne turkey the eastern pontides orogenic belt is one of the most complex geodynamic settings in the alpine himalayan belt due to the lack of systematical geological and geophysical data in this study 1d crustal structure and p wave velocity distribution obtained from gravity modeling and seismological data in the area has been used for the development of the thermal model of the eastern pontides orogenic belt the computed temperature depth profiles suggest a temperature of 590 60 c at a moho depth of 35 km indicates the presence of a brittle ductile transition zone this temperature value might be related to water in the subducted crust of the tethys oceanic lithosphere the curie temperature depth value of 29 km which may correspond to the crustal magma chambers is found 5 7 km below the moho depth surface heat flow density values vary from 66 5 and 104 7 mw m 2 high mantle heat flow density value of 48 mw m 2 is obtained for the area should be related to melting of the lithospheric mantle caused by upwelling of asthenosphere

a multiscale numerical study of hurricane andrew 1992 part i explicit simulation and verification abstract in this study the inner core structures of hurricane andrew 1992 are explicitly simulated using an improved version of the penn state ncar nonhydrostatic two way interactive movable triply nested grid mesoscale model mm5 a modified betts miller cumulus parameterization scheme and an explicit microphysics scheme were used simultaneously to simulate the evolution of the larger scale flows over the coarser mesh domains the intense storm itself is explicitly resolved over the finest mesh domain using a grid size of 6 km and an explicit microphysics package containing prognostic equations for cloud water ice rainwater snow and graupel the model is initialized with the national centers for environmental prediction analysis enhanced by a modified moisture field a model generated tropical storm like vortex was also incorporated a 72 h integration was made which covers the stages from the storm s initial deepening to a near category 5 hurricane intensity and the landfall over florida as

flat mantle reflectors in eastern china possible evidence of lithospheric thinning abstract recent 24 s deep seismic reflection records revealed five flat reflectors in the lithospheric mantle in eastern china with increasing depth they are named m1 to m5 and can be seen on both field single shot and stacked records reflector m1 corresponds to the moho discontinuity whereas m5 may be the reflection from the bottom of the current lithosphere which is about 78 km deep according to geothermal measurements the other three reflectors seem peculiar and might result from interactions between the lithosphere and deeper mantle based on lithological and geochemical data it is suggested that the lithosphere has been thinned from about 150 km to about 60 km in the late mesozoic and then has been thickened to about 78 km during the cenozoic the thinning process produced a granulite layer in the old lower crust caused by magmatic underplating whereas an eclogite layer formed beneath owing to the subduction of the paleo tethys and yangtze craton during the permian and early mesozoic reflector m2 at about 12 s two way traveltime twt might result from the paleozoic moho which represents the boundary between the previous granulite and eclogite facies reflector m3 at about 14 s might correspond to the bottom of the eclogite layer beneath which the old lithospheric mantle remained the old and the newly developed mantle may have different compositions resulting in reflector m4 the multi layered mantle reflectors demonstrate a mantle structure that possibly correlates with the lithospheric thinning process that occurred in eastern china during the late mesozoic the discovery of multi layered mantle reflectors in the studied areas indicates a high heterogeneity of the upper mantle reflection seismology with improved technology together with velocity and resistivity imaging and rock physics measurements can provide more details of the heterogeneity and related dynamic processes that occurred in the lithospheric mantle

genesis of twin tropical cyclones as revealed by a global mesoscale model the role of mixed rossby gravity waves 1 in this study it is proposed that twin tropical cyclones tcs kesiny and 01a in may 2002 formed in association with the scale interactions of three gyres that appeared as a convectively coupled mixed rossby gravity ccmrg wave during an active phase of the madden julian oscillation mjo this is shown by analyzing observational data including ncep reanalysis data and meteosat 7 ir satellite imagery and performing numerical simulations using a global mesoscale model a 10 day control run is initialized at 0000 utc 1 may 2002 with grid scale condensation but no sub grid cumulus parameterizations the ccmrg wave was identified as encompassing two developing and one non developing gyres the first two of which intensified and evolved into the twin tcs the control run is able to reproduce the evolution of the ccmrg wave and thus the formation of the twin tcs about two and five days in advance as well as their subsequent intensity evolution and movement within an 8 10 day period five additional 10 day sensitivity experiments with different model configurations are conducted to help understand the interaction of the three gyres leading to the formation of the tcs these experiments suggest the improved lead time in the control run may be attributed to the realistic simulation of the ccmrg wave with the following processes 1 wave deepening intensification associated with a reduction in wavelength and or the intensification of individual gyres 2 poleward movement of gyres that may be associated with boundary layer processes 3 realistic simulation of moist processes at regional scales in association with each of the gyres and 4 the vertical phasing of low and mid level cyclonic circulations associated with a specific gyre

diurnal patterns of rainfall in northwestern south america part ii model simulations abstract this second paper of a three part series documents the ability of the fifth generation pennsylvania state university ncar mesoscale model mm5 to successfully replicate some known aspects of the rainfall of northwestern south america the success of the control simulation justifies the use of the model in part iii for sensitivity experiments and more detailed diagnosis the simulation is produced using multiply nested grids with grid increments from 72 km down to 2 km three coarser resolution grids are integrated for a period of 10 days with the finest resolution grid run for a 2 day subset of that period several features of the rainfall field are examined as metrics of the model s performance on the largest scales the model reasonably simulates easterly waves in the western atlantic and caribbean although it tends to develop them into tropical cyclones too readily over the amazon river basin diurnally initiated rainbands are observed to propagate westward crossing the basin in 2 3 day

a spatial filter approach to evaluating the role of convection on the evolution of a mesoscale vortex abstracta new spatial filter is proposed that exploits a spectral gap in power between the convective scale and the system vortex scale during tropical cyclone tc genesis simulations using this spatial separation this study analyzes idealized three dimensional numerical simulations of deep moist convection in the presence of a symmetric midlevel vortex to quantify and understand the energy cascade between the objectively defined convective scale and system scale during the early stages of tropical cyclogenesis the simulations neglect surface momentum heat and moisture fluxes to focus on generation and enhancement of vorticity within the interior to more completely close off the energy budget and to be consistent for comparison with prior benchmark studies of modeled tc genesis the primary contribution to system scale intensification comes from the convergence of convective scale vorticity that is supplied by vortical hot towers vhts they contribute more than the convergence of system scale v

carboniferous and triassic eclogites in the western dabie mountains east central china evidence for protracted convergence of the north and south china blocks shrimp u pb dating and laser ablation icp ms trace element analyses of zircon from four eclogite samples from the north western dabie mountains central china provide evidence for two eclogite facies metamorphic events three samples from the huwan shear zone yield indistinguishable late carboniferous metamorphic ages of 312 5 307 4 and 311 17 ma with a mean age of 309 3 ma one sample from the hong an group 1 km south of the shear zone yields a late triassic age of 232 10 ma similar to the age of ultra high pressure uhp metamorphism in the east qinling dabie orogenic belt ree and other trace element compositions of the zircon from two of the huwan samples indicate metamorphic zircon growth in the presence of garnet but not plagioclase namely in the eclogite facies an interpretation supported by the presence of garnet omphacite and phengite inclusions zircon also grew during later retrogression zircon cores from the huwan shear zone have ordovician to devonian 440 350 ma ages flat to steep heavy ree patterns negative eu anomalies and in some cases plagioclase inclusions indicative of derivation from north china block igneous and low pressure metamorphic source rocks cores from hong an group zircon are neoproterozoic 780 610 ma consistent with derivation from the south china block in the western dabie mountains the first stage of the collision between the north and south china blocks took place in the carboniferous along a suture north of the huwan shear zone the major triassic continent continent collision occurred along a suture at the southern boundary of the shear zone the first collision produced local eclogite facies metamorphism in the huwan shear zone the second produced widespread eclogite facies metamorphism throughout the dabie mountains sulu terrane and a lower grade overprint in the shear zone

radiogenic heat production in the lithosphere of sulu ultrahigh pressure metamorphic belt abstract the chinese continental scientific drilling ccsd project is located at the sulu ultrahigh pressure metamorphic uhpm belt it offers a unique opportunity for studying the radiogenic heat production of both shallower and deeper rocks based on the concentrations of radiogenic elements u th and k on 349 samples from main hole of ccsd ccsd mh pilot holes and exposures we determined radiogenic heat productions of all major rock types in the sulu uhpm belt results show the mean values of orthogneiss and paragneiss are respectively 1 65 0 81 and 1 24 0 61 w m 3 due to different composition and grade of retrogressive metamorphism the eclogites display significant scatter in radiogenic heat production ranging from 0 01 to 2 85 w m 3 with a mean of 0 44 0 55 w m 3 the radiogenic heat production in ultramafic rocks also varies within a large range of 0 02 to 1 76 w m 3 and the average turns out to be 0 18 0 31 w m 3 based on the measurements and crustal petrologic model the vertical distribution model of heat production in sulu crust is established the resulting mean heat production 0 76 w m 3 contributes 24 mw m 2 to the surface heat flow 1 d thermal model indicates that the temperature at the moho reaches above 750 c and the thermal thickness of the lithosphere is 75 km in good agreement with the geophysical results the high teat flow 75 mw m 2 together with thin lithosphere presents strong support for the extension events during the late cretaceous and cenozoic

adakites the key to understanding lile depletion in granulites abstract for more than 20 years it has been argued that granulites of the lower continental crust are depleted in fluid mobile elements such as cs rb u and th either because they were removed by melting of the lower crust or through dehydration we argue that there is little evidence for a simple relationship between granulite facies metamorphism and element depletion and propose that for felsic orthogneisses the depletion may be a primary feature of crust generation processes modern adakites show a range of fluid mobile element ratios and adakites from the austral volcanic zone avz chile show fluid mobile element ratios very similar to those found in lower crustal felsic granulites this suite of adakites has a strong slab derived component we propose that modern adakites of the type found in the austral volcanic zone are analogous in their genesis to lower crustal felsic granulites and that their mafic precursors were already depleted in fluid mobile trace elements prior to melting an incremental melting model in which fluid mobile elements are released from an eclogitic slab prior to partial melting can explain the fluid mobile element behaviour of both modern adakites and lower crustal felsic granulites

magnetic petrology of high fe ti eclogites from the ccsd main hole implications for subduction zone magnetism 1 the high fe ti eclogites with exsolved lamellar in 530 600 m depths from the chinese continental scientific drilling ccsd main hole in the sulu ultra high pressure uhp metamorphic belt eastern china record an anomalously high susceptibility natural remanent magnetization nrm and koenigsberger ratio q nrm ji ji is induced magnetization this provides us with a good opportunity to study the effects of magnetic minerals and exsolution lamellae on the magnetic properties of deep rocks in this paper we have measured systematically magnetic properties and mineral assemblage and structure for three special samples no 83 no 86 and no 89 results show that these fe ti rich eclogites are the result of the fine grained titano magnetite exsolution in pyroxene and lamellar structure consisting of finely interlayered ilmenite and hematite in exsolved hemo ilmenite we found that the dominant fe bearing oxide minerals in samples studied are ilmenite hematite hem ilm up to 25 little titano magnetite and pyrite the ferromagnetic susceptibility is mainly controlled by fine grained titano magnetite and nrm is closely related to the exsolved lamellar structure we hence propose that the anomalous magnetism of these eclogites observed in our samples is the result of exsolution from homogenous pyroxene and ilmeno hematite during cooling and decompression processes these fe ti rich eclogites might be one of the sources of high magnetic anomalies observed in the sulu subduction zone eastern china

heat moisture and momentum budgets of isolated deep midlatitude and tropical convective clouds as diagnosed from three dimensional model output part ii sensitivity to ice phase and small changes in ambient shear strength and low level moisture supply abstract this project uses a three dimensional anelastic cloud model with a simple ice phase parameterization to evaluate the feedback of isolated deep convective clouds over a horizontal scale comparable to one grid cell in typical mesoscale numerical weather prediction models a more specific focus in this paper is the sensitivity of the feedback to modest changes in the initial vertical wind shear intensity and low level moisture supply as well as to the ice phase two parallel sets of comparative simulations are run for a quasi steady severe oklahoma supercell thunderstorm in strong vertical wind shear versus a weaker less persistent and narrower tropical atlantic cumulonimbus with a slowly decaying and pulsating updraft in much weaker shear the horizontal reynolds averaging approach of anthes is adopted to diagnose the budgets for heat moisture and horizontal momentum several similarities and differences between the midlatitude and tropical control experiments were delineated in part i the ma

a review of water contents and ductile deformation mechanisms of olivine implications for the lithosphere asthenosphere boundary of continents abstract water plays an important role in the ductile deformation and evolution of the upper mantle water contents of natural olivine from 240 samples reveal a wide variation of 0 170 ppm h2o suggesting heterogeneous water distribution in the continental upper mantle the average water contents 17 13 ppm h2o in kimberlite nodules provide the best estimation of water concentrations in olivine in the lithosphere beneath cratons the very low water contents 7 9 ppm h2o of olivine from basalt xenoliths are caused by significant hydrogen loss during transport while the high values 44 34 ppm h2o in olivine megacrysts from kimberlites reflect restricted fluid rich conditions in the upper mantle to compare deformation in different tectonic environments the western superior province canada the dabie mountains and the north jiangsu basin china are selected to represent an archean craton an orogenic belt and a rift basin respectively using recent flow laws of olivine deformation maps of dry and wet olivine are constructed under p t conditions of the three tectonic units and in a continental subduction zone characterized by p 6 28 gpa and t 900 c for dry olivine diffusion creep is the dominant mechanism in all the cases which is contrary to the widely observed crystal preferred orientation of olivine in peridotites and seismic anisotropy observations for wet olivine only a small amount of water 50 h 106 si can remarkably decrease the stress of dislocation creep and increase contribution of dislocation creep to the deformation of olivine the strain rate profiles of olivine indicate a transition from dislocation creep to diffusion creep at a depth of 220 km which can be related with the lehmann discontinuity characterized by a rapid decrease in seismic anisotropy however the pressure induced fabric transition from 100 slip to 001 slip may be responsible for the lehmann discontinuity in subduction zones therefore rheology of the continental upper mantle is controlled by power law creep of wet olivine and diffusion creep is the dominant deformation mechanism in the deep upper mantle especially for fine grained peridotites the mechanical lithosphere asthenosphere boundary lab can be defined by the characteristic pressure derivative of effective viscosity the sharp lab beneath the dabie mountains and the sulu terrane favors the lithosphere asthenosphere decoupling while the diffuse lab beneath the western superior province will protect the continental root from convective erosion and mantle metasomatism the long term preservation of the continental roots can be attributed to a large viscosity contrast temperature contrast at a depth of 150 km

numerical simulations of the genesis of hurricane diana 1984 part ii sensitivity of track and intensity prediction abstract the authors examine numerous simulations that probe the dynamics governing the intensification and track of tropical cyclone diana 1984 simulated in part i the development process is fundamentally dependent on a preexisting upper tropospheric trough ridge couplet this couplet focuses mesoscale vertical motion that in turn produces lower tropospheric potential vorticity pv anomalies which form the seed for the tropical storm removal of this trough ridge couplet from the initial conditions eliminates cyclogenesis the simulated rate of development of diana in the prehurricane phase depends principally on choices of cumulus parameterization boundary layer treatment sea surface temperature and grid spacing simulations with cumulus schemes that allow more grid scale precipitation on the 9 km grid exhibit unrealistic grid scale overturning and slower intensification primarily due to production of cyclonic vorticity anomalies at large radii use of an innermost nest with 3 km grid spacing

the impact of horizontal grid spacing on the microphysical and kinematic structures of strong tropical cyclones simulated with the wrf arw model abstract using the advanced weather research and forecasting numerical model the impact of horizontal grid spacing on the microphysical and kinematic structure of a numerically simulated tropical cyclone tc and their relationship to storm intensity was investigated with a set of five numerical simulations using input data for the case of hurricane rita 2005 the horizontal grid spacing of the parent domain was systematically changed such that the horizontal grid spacing of the inner nest varied from 1 to 5 km by an increment of 1 km this while keeping geographical dimensions of the domains identical within this small range of horizontal grid spacing the morphology of the simulated storms and the evolution of the kinematic and microphysics field showed noteworthy differences as grid spacing increased the model produced a wider more tilted eyewall a larger radius of maximum winds and higher amplitude low wavenumber eyewall asymmetries the coarser resolution simulations also produced larger v

heat flow heat generation and crustal temperatures in the northern canadian cordillera thermal control of tectonics 1 the heat flow in the northern canadian cordillera between 59 and 64 n is very high 105 22 mw m2 the average upper crust heat generation is 4 6 2 4 microw m3 giving a reduced deep heat flow of 59 mw m2 similar to the southern canadian cordillera 49 53 n estimated moho temperatures of 800 1000 c and lithosphere only 50 60 km thick are substantiated by slow upper mantle seismic velocities and by high elevations associated with crust only 32 35 km thick the new data support the conclusion that all of the north and south america cordilleras are hot the paleoproterozoic wopmay orogen to the east has a remarkably high heat flow of 90 15 mw m2 for such an old and stable region however basement samples indicate high heat generation and estimated deep temperatures are intermediate between the cordillera and the slave craton further to the east heat flow from the yellowknife area of the slave craton 53 mw m2 implies low lithosphere temperatures in agreement with kimberlite xenolith p t data the high temperatures in the cordillera result in a very thin and weak lithosphere and may allow a lower crust detachment the north and central cordillera have been inland of the coastal queen charlotte transform fault since subduction stopped in the eocene thus some process has maintained high temperatures in the former back arc for more than 40 ma

a minimal three dimensional tropical cyclone model abstract a minimal 3d numerical model designed for basic studies of tropical cyclone behavior is described the model is formulated in coordinates on an f or plane and has three vertical levels one characterizing a shallow boundary layer and the other two representing the upper and lower troposphere respectively it has three options for treating cumulus convection on the subgrid scale and a simple scheme for the explicit release of latent heat on the grid scale the subgrid scale schemes are based on the mass flux models suggested by arakawa and ooyama in the late 1960s but modified to include the effects of precipitation cooled downdrafts they differ from one another in the closure that determines the cloud base mass flux one closure is based on the assumption of boundary layer quasi equilibrium proposed by raymond and emanuel it is shown that a realistic hurricane like vortex develops from a moderate strength initial vortex even when the initial environment is slightly stable to deep convect