lacustrine fan deltaic sedimentation in a proterozoic rift basin the sopa brumadinho tectonosequence southeastern brazil abstract the sopa brumadinho tectonosequence 100 to 200 m thick is the fourth unit in ascending order of the up to 2000 m thick mesoproterozoic espinhaco supergroup representing the depositional products of the third and main phase of the rift stage of the espinhaco basin the sopa brumadinho tectonosequence in the study area consists of diamond bearing lacustrine fan delta deposits bounded by prominent angular and erosional unconformities detailed lithofacies studies were carried out in the central part of the southern serra do espinhatco southeastern brazil to characterize the paleogeography and basin fill architecture of the sopa brumadinho tectonosequence thirteen lithofacies are present massive clast supported conglomerates lithofacies ug cs inversely graded clastsupported conglomerates lithofacies ig cs normally graded clast supported conglomerates lithofacies ng cs massive to crudely stratified clast supported conglomerates lithofacies cs cs sandy matrix supported conglomerates lithofacies s ms muddy matrix supported conglomerates lithofacies m ms talus breccia clast supported conglomerates lithofacies tb cs massive sandstones lithofacies sm horizontal stratified sandstones lithofacies sh trough cross stratified sandstones lithofacies st planar cross stratified sandstones lithofacies sp graded stratified sandstones lithofacies sg and pelites lithofacies p they represent the products of several types of subaerial and subaqueous sediment gravity flows ranging from turbidity currents to cohesive debris flows and ephemeral braided streams the deposits are usually arranged in coarsening to fining upward tectono depositional intervals each tectono depositional interval represents a progradational lobe which starts at the base with lacustrine pelites and evolves with time from distal subaqueous to proximal subaerial characteristics the fining upward part represents the abandonment phase of the depositional lobes the origin characteristics distribution and spatial arrangement of the various lithofacies the interbedding of gravityflow and stream flow deposits the predominance of debris flow conglomerates over aqueous current formed ones the semi radial fan like dispersion pattern of the paleocurrents and the recognition of associated subaerial and subaqueous depositional settings are all indicative of a lacustrine alluvial fan fan delta environment or a fan delta system an interplay between several intrabasinal and extrabasinal controls probably determined the fan evolution the sedimentation of the lacustrine fan delta systems of the sopa brumadinho tectonosequence probably took place in a n s elongated continental rift basin compartmentalized by n s trending normal faults and w e trending transfer faults under a tropical semi arid climate the basin fill architecture was probably determined by episodic subsidence clockwise block tilting and asymmetric graben evolution as well as by inherited characteristics of the source area additionally a new descriptive scheme for classification of conglomerate lithofacies is here proposed

parametric representation of the primary hurricane vortex part i observations and evaluation of the holland 1980 model although numerical models are essential to hurricane forecasting many other applications require only statistical depiction of the wind distribution in holland s 1980 parametric profile radius of maximum wind maximum wind and a measure of the profile width describe the radial variation of the axisymmetric wind variants of the holland profile are used to predict insurance underwriting risk ocean response and storm surge inundation since these calculations guide high stakes financial and emergency managment decisions it is logical to test them against observations the hurricane research division s flight level database archives observations were obtained by noaa and u s air force reserve aircraft the data considered here are winds and geopotential heights observed during 606 lower and midtropospheric flights into atlantic and eastern pacific tropical cyclones during 1977 2000 the 493 profiles that meet quality control criteria are seasonally geographically representative least squares fits of the holland model to these data provide evaluation of the parameters distributions and critical examination of the profile s realism individual fitted profiles differ from the observations in a consistent pattern the areas of strong winds in the eyewall and of nearly calm winds at the vortex center are too wide beyond 2 or 3 times the eye radius the wind decreases too rapidly with distance from the center although the average bias in fitted profiles is 1ms 21 the root mean square error is 4 2 m s 21 5 2 m s21 for independent data maximum winds estimated from the fitted holland profile height wind relation average 2 5 m s 21 too strong with an rms error of 6 5 m s 21 the pattern of too strong wind spread over too much real estate exaggerates the occurrence of winds stronger than 50 m s 21 by 50

process and discharge estimation in ephemeral channels canadian rocky mountains process determinations and discharge estimates are made for 10 steep alpine channels in the front and main ranges of the southern canadian rocky mountains the catchments which range in size from 0 17 to 1 13 km2 are sufficiently small that their runoff patterns are dominantly ephemeral and are characterized by processes that include water floods debris flows and snow avalanches longitudinal and cross sectional channel profiles demonstrate the importance of bedrock control and the influence of one or more dominant processes debris flow channels have been partially scoured by water floods and avalanche and debris flow sediments are noted in modified alluvial channels the distribution and sorting of sediments support the multiple process origin of specific channels or channel reaches the discrimination of channel processes is essential for estimates of channel discharge slope area and competence methods employed in fluvially dominated reaches of the 10 channels yield maximum instantaneous discharge

intense sub kilometer scale boundary layer rolls observed in hurricane fran high resolution observations obtained with the doppler on wheels dow mobile weather radar near the point of landfall of hurricane fran 1996 revealed the existence of intense sub kilometer scale boundary layer rolls that strongly modulated the near surface wind speed it is proposed that these structures are one cause of geographically varying surface damage patterns that have been observed after some landfalling hurricanes and that they cause much of the observed gustiness bringing high velocity air from aloft to the lowest observable levels high resolution dow radar observations are contrasted with lower resolution observations obtained with an operational weather radar which underestimated peak low level wind speeds

north atlantic hurricanes 1977 99 surface hurricane force wind radii abstract the hurricane research division noaa amol hrd flight level data archive of 1977 99 north atlantic hurricanes is used to create radial profiles of earth relative surface wind speeds radii of hurricane force winds are determined directly from these generated profiles the distributions of hurricane force wind radii stratified by minimum central pressure and quadrant relative to the direction of storm motion indicate marked variability among storms however a model which uses storm parameters to predict the radius of hurricane force winds in a given quadrant of a hurricane does seem feasible roughly three quarters of the variance in the hurricane force wind radii of minimal hurricanes and about one half of the variance in the hurricane force wind radii of major hurricanes is explained by parameters of the storm enough to make a predictive model of significant value in addition cumulative two dimensional probability distributions of hurricane force wind radii may have some utility for hurr

holocene rhythms of soil formation and sedimentation in the central russian upland abstract for the first time the rhythms of soil formation and accumulation of sediments in holocene in the central russian upland were determined on the basis of radiocarbon analysis of slope balka and floodplain soils and deposits buried paleosols of different ages were distinguished early atlantic pd5 7600 6700 yr bp late atlantic pd4 6180 4800 yr bp subboreal pd3 4150 3000 yr bp subatlantic pd2 2380 1050 yr bp buried allerod preboreal and boreal paleosols and modern 200 yr old soil on newly deposited sediments were studied the paleosols were formed within long more than 1200 yr phases of geomorphological stability and buried in transitional accumulative landscapes alluvial proluvial deluvial and other holocene deposits were accumulated within shorter phases of morpholithogenesis these pedogenetic and morpholithogenetic phases follow a 1850 yr cycle

the boundary layer winds in hurricanes danielle 1998 and isabel 2003 abstract this paper describes the boundary layer wind structure and dynamics of hurricanes danielle 1998 and isabel 2003 based on the analysis of high resolution global positioning system dropwindsonde data and simulation of the flow by a three dimensional boundary layer model produced by kepert and wang the observations show that the hurricane boundary layer has a complex three dimensional structure with large variability over small distances the analysis emphasizes three aspects the degree of gradient wind balance the radially varying depth of the boundary layer and the strength of the near surface wind speed relative to that at a higher level each aspect is compared both with results obtained in a simulation of the individual storm by kepert and wang s model and with theoretical predictions the observations show that the boundary layer depth decreases toward the center of the storm consistent with theoretical arguments the strongest azimuthal winds occur near the top of but still within

a modeling study of typhoon nari 2001 at landfall 2 structural changes and terrain induced asymmetries 1 in this study a series of model output diagnoses using the cloud resolving simulations of typhoon nari 2001 with or without taiwan topography is performed to gain insight into the landfall characteristics of the storm as it moves across taiwan island various kinematic and precipitation features prior to and after landfall are examined with a focus on the dynamic effects of taiwan s high topography upon the generation of nari s asymmetric structures results show that tangential winds weaken whereas the low level inflows and midlevel outflows increase after landfall due to the increased friction and terrain blocking meanwhile the eye wall updrafts exhibit more cellular structures and tend to tilt more outward with height over the high topography however nari s primary and secondary circulations are stronger in the presence of terrain than those without terrain the radii of the maximum winds and the eye wall updrafts could contract further after landfall with more pronounced contraction occurring in the portion of the eye wall where more terrain retardation and blocking are present in particular the high topography allows the elevated low equivalent potential temperature e air over the rugged terrain to intrude into the inner core region causing the breakdown of the eye wall it is concluded that the interaction of nari s circulations with the elevated low e air combined with topographical effects accounts for most of the asymmetrical structures after landfall

understanding the genesis of ultramafic soils and catena dynamics in niquelândia brazil this study focuses on the fate of chromium during ultramafic weathering under tropical conditions three soils were studied along a characteristic catena on the ultramafic outcrop of niquel ndia brazil in these soils the cr bearing minerals are inherited chromites 15 4 26 8 wt cr and magnetites 0 4 4 8 wt cr and secondary minerals such as iron oxides 0 2 wt cr or ni smectites 0 6 8 wt cr indeed during weathering cr liberated from primary minerals can first be incorporated into ni smectites garnierite or fe oxides as the weathering continues smectites become unstable and cr liberated into the soil solution and incorporates in fe oxides in this oxidized environment fe and mn are oxidized and oxides can incorporate elements like cr ni and al two types of chromites were distinguished i e a vein type vc and a rock type rc according to their composition chromites could be used as tracer of pedogenesis processes due to the distinct composition of vc and rc types they allow us to show that the upper part of some soil profile results exclusively from colluvial processes and the lower part of the profile results from the ultramafic bedrock weathering the chromite tracer allows us to propose a model of the catena evolution

structure of the eye and eyewall of hurricane hugo 1989 on 15 september 1989 one of noaa s wp 3d research aircraft n42rf lower aircraft la penetrated the eyewall of hurricane hugo the aircraft had an engine fail in severe turbulence while passing the radius of maximum wind and before entering the eye at 450 m altitude after the aircraft returned to controlled flight within the 7 km radius eye it gained altitude gradually as it orbited in the eye observations taken during this period provide an updated model of the inner core structure of an intense hurricane and suggest that la penetrated an intense cyclonic vorticity maximum adjacent to the strongest convection in the eyewall eyewall vorticity maximum evm this evm was distinct from the vortex scale cyclonic circulation observed to orbit within the eye three times during the 1 h that la circled in the eye at the time hugo had been deepening rapidly for 12 h the maximum flight level tangential wind was 89 m s 1 at a radius of 12 5 km however the primary vortex peak tangential wind derived from a 100 s filter of the flight level data was estimated to be 70 m s 1 also at 12 5 km radius the primary vortex tangential wind was in approximate gradient wind balance was characterized by a peak in angular velocity just inside the radius of maximum wind and had an annular vorticity structure slightly interior to the angular velocity maximum the evm along the aircraft s track was roughly 1 km in diameter with a peak cyclonic vorticity of 1 25 10 1 s 1 the larger circulation center with a diameter 15 km was observed within the eye and exhibited an average orbital period of 19 min this period is about the same as that of the angular velocity maximum of the axisymmetric mean vortex and is in reasonable agreement with recent theoretical and model predictions of a persistent trochoidal wobble of circulation centers in mature hurricane like vortices this study is the first with in situ documentation of these vortical entities which were recently hypothesized to be elements of a lower tropospheric eye eyewall mixing mechanism that supports strong storms

stochastic excitation of seismic waves by a hurricane stochastic excitation of seismic waves by a hurricane toshiro tanimoto and anne valovcin department of earth science and earth research institute university of california santa barbara california 93106 usa corresponding author email toshiro geol ucsb edu abstract we investigate how a tropical cyclone hurricane isaac in 2012 generated seismic ground motions using seismic and barometric data from the earthscope network in the frequency band 0 01 0 02 hz seismic and surface pressure amplitudes show a systematic decreasing trend with distance from the center of the hurricane however the decreasing rate is much higher for seismic waves than for pressure we develop a stochastic theory of seismic wave excitation by surface pressure that connects these two observed data sets surface pressure is the excitation source and seismic data are the resulting seismic wave field this theory contains two parameters i the pressure power spectral density pressure psd s p and ii the correlation length in the pressure field l using the formula we solve for the spatial variation of correlation lengths the solution shows that longer correlation lengths in pressure are near the hurricane center because seismic wave excitation is proportional to l 2 s p the excitation for seismic waves becomes effectively more localized closer to the center also the scaling relation between l and s p leads to an excitation source which is approximately proportional to the third power of surface pressure this centralized source for seismic wave excitation explains why the

geochemical and eco toxicological characteristics of stream water and its sediments affected by acid mine drainage abstract in assessing the adverse effects of acid mine drainage amd the chemistry of amd and stream water i e ph and toxic metal concentrations has been accounted as important monitoring parameters and its characteristics are regulated in many countries yet for the precise evaluation of eco toxicological effect on amd receiving streams a more comprehensive evaluation parameter has to be recognized as a mandatory parameter in this study eco toxicological correlations between chemical properties of water and sediments collected from an amd receiving stream were investigated at an abandoned mine site in korea the stream water in the amd watercourse near the mine adit that is highly acidic and contains high concentrations of heavy metals has been neutralized as the amd became diluted with nearby natural stream water the toxicity of stream water showed a relatively strong correlation with the ph and dissolved metal concentrations of water implying the toxic effects of stream water on its stream biota in contrast the toxicity results obtained from stream sediments hardly showed close correlation with the composition of toxic elements particularly with enriched arsenic

ramparts and walls building techniques of kites in the negev highland abstract remarkably the largest archaeological game traps ever recorded in the near east are found in arid landscapes both on plains and in hilly terrains this paper describes the construction methods used on steep slopes in the negev highland apparently in some cases a massive rampart rather than a free standing wall was built around the trap s head the details reflect careful planning and heavy duty work including leveling and then using more than 100 t of stone for the rampart construction new 14 c data date the sayarim site to the early bronze age minimum age and the pitam site to pre late bronze age

the geochemical signature of suspended sediments in the parana river basin implications for provenance weathering and sedimentary recycling abstract the parana river basin is one of the largest hydrological systems in south america the present study focuses on the mineralogical and chemical composition of the suspended sediments exported by the parana river to the atlantic ocean with the aim of analyzing their provenance the chemical weathering signature and the likelihood of sedimentary recycling the particulate matter of the middle parana river and its main tributaries i e the paraguay and the upper parana rivers is mostly composed of quartz plagioclase k feldspar and clays such as illite and kaolinite different geochemical approaches indicate that the suspended sediments transported by the parana river preserve the chemical signature of its sources and its composition is not significantly modified during transport these sediments are mainly supplied by acidic arc sources located in the andean headwaters of the bermejo and pilcomayo rivers and transported by the paraguay river and by tholeiitic basalts outcropping in the headwaters of the upper parana river the incomplete mixing of both main tributaries produces a transverse geochemical asymmetry in the particulate material of the middle parana river which was detected 32 km downflow the confluence the suspended load transported by the paraguay river which includes the contributions from the bermejo and pilcomayo rivers indicates incipiently to moderately weathering whereas the particulate matter exported by the upper parana river reveals a higher degree of chemical alteration this is the result of the different lithology and climatic regimes that prevail in the headwaters of both tributaries the weathering signature of the middle parana river s suspended load resembles that of the paraguay river which in turns supplies most of the particulate matter through the bermejo river this work also shows that the suspended load exported by the parana river basin has a mixed origin where the chemical signatures from young materials derived from undifferentiated volcanic rocks and from recycled materials affected by intracrustal differentiation can be distinguished

warm cores eyewall slopes and intensities of tropical cyclones simulated by a 7 km mesh global nonhydrostatic model abstractbased on the data of a 1 yr simulation by a global nonhydrostatic model with 7 km horizontal grid spacing the relationships among warm core structures eyewall slopes and the intensities of tropical cyclones tcs were investigated the results showed that stronger tcs generally have warm core maxima at higher levels as their intensities increase it was also found that the height of a warm core maximum ascends descends as the tc intensifies decays to clarify how the height and amplitude of warm core maxima are related to tc intensity the vortex structures of tcs were investigated by gradually introducing simplifications of the thermal wind balance it was established that warm core structures can be reconstructed using only the tangential wind field within the inner core region and the ambient temperature profile a relationship between tc intensity and eyewall slope was investigated by introducing a parameter that characterizes the shape of eyewalls and can be evaluated from satellite m

a simulation model of morphological vegetation and sediment changes in ephemeral streams a model to simulate channel changes in ephemeral river channels and to test the effects of hydrological changes due to climate change and sol or land use change was developed under the auspices of the eu funded medalus programme mediterranean desertification and land use the model changism channel change gis simulation model is designed to simulate the effect of channel flow events and of climate conditions on morphology sediment and vegetation through sequences of events and conditions over periods of up to several decades the modelling is based on cellular automata but with calculations for water and sediment continuity process rules have both deterministic and stochastic elements an important feature of the model is that it incorporates feedback elements between each event the main aim of the model is to indicate the likely outcomes of events and combinations of conditions it is linked to gis for both input and output the modelling is based on a channel reach and state is input as gis layers of morphology dem sediment and vegetation cover and state other initial conditions of soil moisture groundwater level and overall gradient are input parameters for processes are read from tables and can be easily changed for successive runs of the model the bases for decisions on process specifications are discussed in this paper initial tests of the operation and sensitivity of the model were made on idealized reaches the model was then tested using data from monitored sites in se spain simulations using clearwater flow worked well but initial simulations using events with sediment loads showed some tendency for excess deposition further tests and modifications are taking place overall the model is one of the most sophisticated that simulates the interaction of flows with sediment and vegetation and the outcomes in terms of erosion deposition morphology sediment cover vegetation cover and plant survival over periods of up to 30 years for the scale of a channel reach copyright 2005 john wiley sons ltd

geochemistry of a soil catena developed from loess deposits in a semiarid environment sierra chica de cordoba central argentina abstract a catenary sequence of soils formed on reworked loess under semiarid climatic conditions was studied four soil profiles located on the piedmont of sierra chica de cordoba central argentina were described classified and geochemically analyzed all soils developed on summit shoulder backslope and toeslope positions were classified as mollisols decarbonatation carbonatation melanization and argilluviation are the main pedogenic processes recognized in these soils which appear to control the differentiation of genetic horizons along the catena different geochemical approaches indicate that there are not substantial variations in the chemical composition of the studied soils along the catena with the exception of the soil in the toeslope position which exhibits slightly differences in general all profiles show weak depletions of mobile elements ca na mg sr u in the upper continental crust ucc normalized diagrams which are attributed to a slight chemical alteration other elements such as fe cr co and ni also exhibit depletions compared to ucc which can be explained by the alteration of ferromagnesian silicates but can also be an inherited feature from the parent material the significant enrichment in as compared to ucc evident in all profiles along the catena is also a typical feature of the pampean plains loess of argentina so the chemical differences in the profile located on the toeslope are mainly attributed to the supply of materials from local sources i e crystalline basement and sedimentary rocks due to its position in the catena statistical correlations and multivariate cluster analyses reinforce the assumption that the geochemistry of the studied soils is inherited from the parent material in addition chemical indices cia icv elemental ratios ba sr rb sr and the a cn k ternary diagram indicate an incipient degree of chemical alteration for these soils compatible with the weathering regime prevailing in the region thus the differentiation of genetic horizons along the catena is the result of weak weathering and pedogenic processes which have not been strong enough to mask the chemical imprint of the parent material

airborne doppler observations of the inner core structural differences between intensifying and steady state tropical cyclones abstractdifferences in the inner core structure of intensifying in intensity increase of at least 20 kt 24 h 1 where 1 kt 0 51 m s 1 and steady state ss intensity remaining between 10 kt 24 h 1 tropical cyclones tcs are examined using composites of airborne doppler observations collected from noaa p 3 aircraft missions the in dataset contains 40 eyewall passes from 14 separate missions while the ss dataset contains 53 eyewall passes from 14 separate missions intensifying tcs have a ringlike vorticity structure inside the radius of maximum wind rmw lower vorticity in the outer core a deeper stronger inflow layer and stronger axisymmetric eyewall upward motion compared with steady state tcs there is little difference in the vortex tilt between 2 and 7 km and both in and ss tcs show an eyewall precipitation and updraft asymmetry whose maxima are located in the downshear and downshear left region the azimuthal coverage of eyewall and outer core precipitation is greater for in tcs

tropical cyclone environments over the northeastern and northwestern pacific based on era 15 analyses abstract this study uses a 1 1 lat long dataset extracted from ecmwf reanalyses for the 15 yr period 1979 93 era 15 to composite environmental characteristics and flow features in the vicinity of named tropical cyclones tcs in the eastern and western north pacific ocean basins tropical cyclones are partitioned into one of four classifications as they pass by selected locations along the axes of maximum frequency and tc tracks weak w strong s intensifying i or dissipating d results of this study show that peak values of rising motion within the same classification are greater for tc composites in the western pacific than for those in the eastern pacific the level of maximum rising motion was at or above the 500 hpa level for all locations and classifications except for the ss at our northernmost point 25 n 130 e in the western pacific their maximum upward motion occurred at 700 hpa it is also found that the latter systems contrary to all other points were located in a reg

pedogenesis of a catena of the farmdale sangamon geosol complex in the north central united states abstract the farmdale sangamon geosol pedocomplex consists of the sangamon geosol and the overlying farmdale geosol which form the most extensive terrestrial record of the last interglacial to glacial transition in the midwest united states the geosol complex formed for upwards of 100 ka extending from the end of mis 6 through 4 for the sangamon geosol then the farmdale geosol for during a brief episode at the end of mis 3 following slow accumulation and pedogenic modification of eolian silt deposited on top of the sangamon geosol our study site consists of a buried paleo hillslope transect that forms a catena enabling evaluation of slope effects on interglacial scale soil formation the sangamon geosol is formed in calcareous and illitic glaciogenic sediment along the catena the sangamon geosol profiles display some morphological changes namely in terms of colors that we interpret as indicators of differences in drainage most thickness and horizonation characteristics are similar all along the transect with intact upper sola horizons ae and e horizons that overlie clay enriched bt horizons the bt horizons contain abundant clay that exists as illuvial clay coatings matrix infills and as mosaic speckled domains the clay originated both by in situ weathering and through illuviation from the clay depleted upper sola slope does not appear to affect bt characteristics beyond redder hues of the matrix and clay coatings in the upper slope position with depth effects of carbonate leaching and infilling of clay in the matrix decrease and clay coatings are restricted to walls of voids adjacent to aggregates clay mineralogy shows illite depletion but no interstratified kaolinite expandable minerals indicating the degree of weathering is not as great as is typical of sangamon geosol profiles formed in loess or in glaciogenic sediment of the central illinois type area clay mineralogy is also stratified with depth coincident with particle size which probably indicates sorting of layers of illitic dolomite and shale variation of horizon and profile characteristics appears to largely be a function of particle size variability and stratification than topographic position in the catena the influence of hillslope position on soil redistribution during formation of the sangamon geosol appears negligible given the uniformity of upper solum horizon thickness and sandy particle size characteristics so we conclude that a bioturbation and rainwash origin of the upper solum and the texture contrast in these profiles is not the best process model explanation we suggest that the base rich nature of these soils led to ecosystem characteristics that discouraged erosion and encouraged infiltration and a lessivage type origin of the texture contrast no convincing evidence of mis 6 through mis 4 loess occurs at this site the farmdale geosol formed in the robein silt which is roxana silt mis 3 loess that was redistributed downslope the robein silt is thicker and finer in the topographic low and indicates the cooler and forested environmental conditions during mis 3 were conducive to downslope movement of soil and also produced greater differences in drainage induced soil morphological changes in the farmdale geosol

chronostratigraphy site formation processes and pollen record of ifri n etsedda ne morocco abstract the rock shelter of ifri n etsedda is located at the southern flank of the kebdana mountains north east morocco at an altitude of around 300 m a s l twenty one radiocarbon ages attest an occupation of the shelter between 10 0 and 6 0 ka cal bp comb decorated pottery also known from other late neolithic sites of the area suggest a later occupation the presence of both epipalaeolithic and neolithic deposits offers the opportunity to study the neolithic transition in the area although the ifri n etsedda deposits contain a short hiatus next to the ifri oudadane shelter west of the melilla peninsula it is one of the few sites in the area allowing this approach the paper combines stratigraphic sedimentological and micromorphological studies in order to reconstruct the complex site formation processes pollen analysis offers exciting insights into environmental change human land use and subsistence strategies a short overview about the artefact assemblage allows the reconstruction of occupation history and a first placement of the site within the archaeological context of the area the epipalaeolithic occupation seems to be clearly bipartite and the ongoing study of the lithic assemblage promises the possibility of further subdivision in the area for the first time discontinuities of the epipalaeolithic might be connected to early holocene rapid climate change events rcc the neolithic occurred at about 7 2 ka cal bp marked by the appearance of pottery perforated snails ovicaprides and cereals hunting gathering and the use of terrestrial molluscs still played an important role during the neolithic as the main occupation phase the late early neolithic between 6 7 to about 6 0 ka cal bp appears striking similarities to other contemporary sites such as el zafrin at the nearby coast and the mtlili open air sites within the lower reaches of the moulouya river suggest that ifri n etsedda is part of a larger settlement cluster providing particular adaptations to mountainous landscapes

low wavenumber structure and evolution of the hurricane inner core observed by airborne dual doppler radar abstract the asymmetric dynamics of the hurricane inner core region is examined through a novel analysis of high temporal resolution three dimensional wind fields derived from airborne dual doppler radar seven consecutive composites of hurricane olivia s 1994 wind field with 30 min time resolution depict a weakening storm undergoing substantial structural changes the symmetric and asymmetric mechanisms involved in this transformation are considered separately to zeroth order the weakening of the primary circulation is consistent with the axisymmetric vortex spindown theory of eliassen and lystad for a neutrally stratified atmosphere vertical shear however increased dramatically during the observation period leading to a strong projection of the convection onto an azimuthal wavenumber 1 pattern oriented along the maximum vertical shear vector recent theoretical ideas elucidating the dynamics of vortices in vertical shear are used to help explain this asymmetry the role of asymmetric vorticity d

airborne doppler radar analysis of supercells during cops 91 abstract on 26 may 1991 noaa p 3 airborne doppler radar data were collected near two tornadic supercells in the southern plains during the cooperative oklahoma profiler studies cops 91 field program the 3 cm radar mounted in the tail of the aircraft was operated using the fore aft scanning technique fast both storms were sampled just minutes after each had produced a tornado the cops 91 storms are the first tornadic supercells to be sampled extensively by airborne doppler radar using the fast methodology pseudo dual doppler analyses of a dissipating storm in southwest kansas show no remaining low level circulation even though the storm had just produced a tornado the analyses of a storm in northwest oklahoma reveal better defined features in the wind field near the surface in contrast to what has been previously observed in post tornadic supercells the cyclonic vorticity in both storms was greater aloft than at low levels the 26 may 1991 storms provide further evidence that supercells often

controls on fan depositional processes in the schist ranges of the southern alps new zealand and implications for debris flow hazard assessment sixteen morphometric and vegetation cover variables associated with 32 debris flow and 28 fluvial fans and their basins in the schist ranges of the southern alps of new zealand are examined the results show statistically significant differences in the area length planimetric shape relief ratio melton s ruggedness r and forest and total vegetation cover between debris flow and fluvial basins and in the apex and toe elevations area and upper and average axial gradients between debris flow and fluvial fans all of these variables except the apex and toe elevations of the fans reflect differences between debris flow and fluvial processes and environmental controls on them discriminant analysis indicates that the relief ratio and melton s r of the basin and upper and average gradients of the fan axis are able to correctly classify debris flow and fluvial fans with almost equally good results obtained by employing only a pair of variables either basin relief ratio and upper fan gradient or basin melton s r and basin shape the lower thresholds at debris flow sites and upper thresholds at fluvial sites for the relief ratio and melton s r of the basin and upper and average gradients of the fan are identified and these as well as the mean values of these variables show significant differences from fans in nearby sedimentary ranges of the southern alps with important implications for the assessment of debris flow hazard on fans fan gradient is found to be closely associated with basin size area and length at debris flow sites but with basin ruggedness relief ratio at fluvial sites both fan types show a weak association between their size and the size of the contributing basin

mechanisms for the generation of mesoscale vorticity features in tropical cyclone rainbands a high resolution tropical cyclone model with explicit cloud microphysics has been used to investigate the dynamics and energetics of tropical cyclone rainbands analysis of the vorticity interactions that occur within the simulated rainbands demonstrates that couplets of cyclonic anticyclonic mesovortices can be produced in outer bands the primary source of this vorticity is the upward tilting of system generated horizontal vorticity by diabatic heating gradients the vertical heating gradient in the stratiform cloud also creates a potential vorticity pv dipole that accelerates the tangential flow and develops a midlevel jet the strength of the jet is enhanced by the vortex pair that is oriented radially across the rainband the fourier decomposition of the absolute vorticity field shows two counterpropagating vortex rossby waves associated with the rainband the wave located on the inner side of the band transports energy toward the vortex center the outer wave is made up of high wavenumbers and uses the vorticity gradients generated by the rainband the results support the hypothesis that the heating profile in the stratiform regions of rainbands generates cyclonic pv across the freezing level which develops a midlevel jet this mechanism creates a vorticity gradient that enables the propagation of vortex rossby waves that could allow the rainbands to interact with the mean flow and potentially influence the evolution of the storm by contributing to the symmetric component of vorticity and the development of secondary eyewalls

evolution of hillslope soils the geomorphic theater and the geochemical play abstract how and how fast do hillslope soils form as the landscape s morphology changes over time here results are shown from an ongoing study that simultaneously examines the morphologic and geochemical evolution of soil mantled hillslopes that have been exposed to distinctively different denudation history in northern sierra nevada california the authors are investigating a tributary basin to the middle fork feather river a major incision signal from the river is well marked in a knickpoint within the tributary basin which stretches from its mouth to the feather river at an elevation of 700 m to the plateau at an elevation of 1500 m hillslopes are significantly steeper below the knickpoint the area s total denudation rates are currently being constrained using cosmogenic radio nuclides but a previous study suggested an order of magnitude difference in total denudation rates below and above the knickpoint when compared with topographic attributes calculated from lidar data physical erosion rates can be modeled as a linear function of ridge top curvature surprisingly over the wide range of total denudation rates soil thicknesses do not vary significantly until a threshold point where soil mantled landscapes abruptly shift to bedrock dominated landscapes bioturbation by tree falls appear to buffer soil thickness over the wide range of physical soil erosion rates from three hillslopes with different physical erosion rates the concentrations of zr which were considered conserved during dissolution and leaching were determined and used as a proxy for the degree of mass losses via chemical denudation there is a general trend that colluvial soils along the hillslopes with lower physical erosion rates are enriched in fine size fractions zr and pedogenic crystalline fe oxides likewise the saprolites show greater degrees of chemical denudation at the sites above the knickpoint presumably because of the saprolites longer turnover time in the slowly eroding landscapes in the two steep hillslopes below the knickpoint no significant or systematic topgraphic trends were found for soil geochemistry however soils show increasing zr enrichment in the downslope direction in the hillslope above the knickpoint which suggests a critical denudation rate beyond which soils turnover time is too short to develop a geochemical catena as detailed crn based soil production rates and catchment scale denudation rates are acquired the data will be combined with a mass balance model to calculate the rates of chemical denudation and weathering in soils and saprolites along the denudation gradient

an estimation of turbulent characteristics in the low level region of intense hurricanes allen 1980 and hugo 1989 this study analyzes the flight level data collected by research aircraft that penetrated the eyewalls of category 5 hurricane hugo 1989 and category 4 hurricane allen 1980 between 1 km and the sea surface estimates of turbulent momentum flux turbulent kinetic energy tke and vertical eddy diffusivity are obtained before and during the eyewall penetrations spatial scales of turbulent eddies are determined through a spectral analysis the turbulence parameters estimated for the eyewall penetration leg are found to be nearly an order of magnitude larger than those for the leg outside the eyewall at similar altitudes in the low level intense eyewall region the horizontal length scale of the dominant turbulent eddies is found to be between 500 and 3000 m and the corresponding vertical length scale is approximately 100 m the results suggest also that it is unwise to include eyewall vorticity maxima evm in the turbulence parameter estimation because the evms are likely to be quasi two dimensional vortex structures that are embedded within the three dimensional turbulence on the inside edge of the eyewall this studyis afirstattempt at estimatingthe characteristics of turbulent flow in the low leveltroposphereof an intense eyewall using in situ aircraft observations the authors believe that the results can offer useful guidance in numerical weather prediction efforts aimed at improving the forecast of hurricane intensity because of the small sample size analyzed in this study further analyses of the turbulent characteristics in the high wind region of hurricanes are imperative

structural and surface features of arc shaped radar echoes along an outer tropical cyclone rainband this study uses ground based dual doppler radar and surface observations to document the structural and surface features of the arc shaped radar echoes asres evident along an outer rainband of typhoon longwang as it approached northern taiwan on 1 october 2005 the particular aim of this study is to explore the possible distinction between the present case previously documented tropical cyclone rainbands tcrs and squall lines the dual doppler derived fields show that the leading precipitation of the studied asres exhibited a convective nature with a sharp horizontal gradient of reflectivity and a significant vertical extent theregionsbehindtheleadingconvectionwerecharacterizedbyband relativerear to frontflowatlowlevels and were associated with a broader area of stratiform precipitation the deep layer of front to rear flow extending from the surface to the upper troposphere was generally present ahead of the asres this flow appearstobeliftedupwardatandimmediatelyaheadoftheleadingedgeofthelow levelrear to frontflowto form rearward tilting updrafts these airflow patterns are similar to those of the convective region of squall lines but differ fundamentally from those of previously documented tcrs that were located closer to the inner core of cyclones the detailed analyses of surface fluctuations during the passage of one of the studied asresfurthershowanabruptpressurerise 2mb atemperaturedrop 48c andapronounceddeceleration of inflow air coincident with the leading heavy precipitation the evaluation presented suggests that the convectively generated cold pool may be important in influencing the structures and propagation of the studied asres

mesoscale and convective scale characteristics of mature hurricanes part i general observations by research aircraft abstract the analysis of instrumented aircraft data from four recent mature hurricanes reveals common mesoscale and convective scale features the structure and organization of the convection precipitation and wind flow are studied by combining the airborne observations using basic instrumentation with quantitative radar measurements three predominant precipitation features seen are 1 the eyewall 2 a stratiform rain region adjacent to and outside the eyewall and 3 rainbands that contain both convective and stratiform regions the eyewall is so named because it surrounds the rain free eye but several additional features distinguish it from other convective bands in the hurricane in particular the updraft tangential wind maximum and highest rainfall have preferred locations relative to each other with the updraft being radially inward from the rain and wind maxima the 10 dbz radar reflectivity contour indicative of the inner edge slopes substantially outward with height and there is evide

genesis age and archaeological significance of a pedosediment in the depression around tell mozan syria abstract a pedosedimentological profile from the ditch surrounding the lower town of the bronze age site of mozan is investigated for its soil and sedimentological characteristics and has been dated in order to gain information on the use of the ditch and on the landscape development surrounding the settlement the depression did not contain large amounts of water flowing or stagnant and probably was used for agricultural purposes accumulation that in part includes anthropogenically derived redeposited and bioturbated debris started at around 2800 cal bc or later and was especially intensive at some time between 2800 and 1000 cal bc deposition may have been caused by intensive agricultural use of the landscape during the urban explosion of the early bronze age or in the early middle bronze age

late holocene erosion events in the valley of teotihuacan central mexico insights from a soil geomorphic analysis of catenas abstract this paper addresses the timing of accelerated soil erosion and landscape degradation in central mexico it shows data on erosion sequences in the valley of teotihuacan an area where agricultural dates back to at least since 1100 bce and an ideal setting to test ideas on the effect of preconquest versus post conquest anthropogenic impacts on the environment the methods include stratigraphy detailed description of soil profiles and soil micromorphology along with analysis of pottery sherds and radiocarbon dating a chronology of events for two catenas focusing on periods of landscape stability and change establish the sequence of erosion events from pre hispanic to modern times six erosion phases are recognized over the last 2000 years in teotihuacan although results suggest that the most intense erosion occurred after spanish conquest in the 16th century several erosion phases took place during pre hispanic times and also in the postcolonial period including the 20th century probable causes for these impacts are related to settlement dynamics population variability and land use changes thus it provides new information for the discussion on the timing and causes of erosion sedimentation and landscape modification in the central mexican highlands during the late holocene

depositional process and alluvial fan drainage basin morphometric relationships near banff alberta canada two distinct types of alluvial fans occur in the bow river valley alberta canada fluvially dominated and debris flow dominated large gently sloping fans dominated by fluvial processes are associated with large and less rugged drainage basins and small rugged basins have produced small steep fans dominated by debris flow processes quantitative analysis demonstrates that strong fan basin morphometric relationships occur despite a short fan history statistical analysis of fan area basin area relationships indicate that debris flow fan areas do not increase in size as quickly as contributing basins the relationship of fluvial fan area to basin area is not statistically significant however this relationship is probably affected by fan erosion examination of fan slope to basin ruggedness relationships indicates that fan slope increases more rapidly than basin ruggedness for both fan types this is likely related to non linear discharge and sediment size effects on fluvial fans and reworking of larger fan surfaces by fluvial processes on debris flow fans

an extreme event in the eyewall of hurricane felix on 2 september 2007 abstractduring a routine penetration into hurricane felix late on 2 september 2007 noaa42 encountered extreme turbulence and graupel flight level horizontal wind gusts of over 83 m s 1 and vertical wind speeds varying from 10 m s 1 downward to 31 m s 1 upward and back to nearly 7 m s 1 downward within 1 min this led the plane to rise nearly 300 m and then return to its original level within that time though a dropwindsonde was released during this event the radars and data systems on board the aircraft were rendered inoperable limiting the amount of data obtained the feature observed during the flight is shown to be similar to that encountered during flights into hurricanes hugo 1989 and patricia 2015 and by a dropwindsonde released into a misovortex in hurricane isabel 2003 this paper describes a unique dataset of a small scale feature that appears to be prevalent in very intense tropical cyclones providing new evidence for eye eyewall mixing processes that may be related to intensity change

rapid development of the tropical cyclone warm core this paper presents a simple theoretical argument to isolate the conditions under which a tropical cyclone can rapidly develop a warm core thermal structure and subsequently approach a steady state the theoretical argument is based on the balanced vortex model and in particular on the associated transverse circulation equation and the geopotential tendency equation these second order partial differential equations contain the diabatic forcing and three spatially varying coefficients the static stability a the baroclinity b and the inertial stability c thus the transverse circulation and the temperature tendency in a tropical vortex depend not only on the diabatic forcing but also on the spatial distributions of a b and c experience shows that the large radial variations of c are typically the most important effect under certain simplifying assumptions as to the vertical structure of the diabatic forcing and the spatial variability of a b and c the transverse circulation equation and the geopotential tendency equation can be solved via separation of variables the resultingradialstructureequationsretainthedynamicallyimportantradialvariationofcandcanbe solvedin terms of green s functions these analytical solutions show that the vortex response to a delta function in the diabatic heating depends critically on whether the heating occurs in the low inertial stability region outside the radius of maximum wind or in the high inertial stability region inside the radius of maximum wind this resultsuggeststhatrapidintensification isfavoredforstormsthathaveat leastsome oftheeyewallconvection inside the radius of maximum wind the development of an eye partially removes diabatic heating from the high inertial stability region of the storm center however rapid intensification may continue if the eyewall heating continues to become more efficient as the warm core matures and static stability increases over the inner core conditions there become less favorable for deep upright convection and the storm tends to approach a steady state

earthquake imprints on a lacustrine deltaic system the kurk delta along the east anatolian fault turkey deltas contain sedimentary records that are not only indicative of water level changes but also particularly sensitive to earthquake shaking typically resulting in soft sediment deformation structures the kurk lacustrine delta lies at the south western extremity of lake hazar in eastern turkey and is adjacent to the seismogenic east anatolian fault which has generated earthquakes of magnitude 7 this paper reevaluates water level changes and earthquake shaking that have affected the kurk delta combining geophysical data seismic reflection profiles and side scan sonar remote sensing images historical data onland outcrops and offshore coring the history of water level changes provides a temporal framework for the depositional record in addition to the common soft sediment deformation documented previously onland outcrops reveal a record of deformation fracturing tilt and clastic dykes linked to large earthquake induced liquefactions and lateral spreading the recurrent liquefaction structures can be used to obtain a palaeoseismological record five event horizons were identified that could be linked to historical earthquakes occurring in the last 1000 years along the east anatolian fault sedimentary cores sampling the most recent subaqueous sedimentation revealed the occurrence of another type of earthquake indicator based on radionuclide dating 137cs and 210pb two major sedimentary events were attributed to the ad 1874 1875 east anatolian fault earthquake sequence their sedimentological characteristics were determined by x ray imagery x ray diffraction loss on ignition grain size distribution and geophysical measurements the events are interpreted to be hyperpycnal deposits linked to post seismic sediment reworking of earthquake triggered landslides this article is protected by copyright all rights reserved

a climatology of hurricane eye formation abstractthis paper presents a climatology of the initial eye formations of a broad set of atlantic tropical cyclones tcs during 1989 2008 a new dataset of structure and intensity parameters is synthesized from the vortex data messages transmitted by routine aircraft reconnaissance using these data together with satellite imagery and other established datasets the times when each tc achieved various stages of eye development are tabulated to form the basis of the climatology about 60 of atlantic tcs form eyes most often aircraft observe the eye structure before it appears in ir satellite imagery eyes tend to form in high potential intensity environments characterized by high sea surface temperatures and low to moderate environmental vertical wind shear a notable discovery is that most 67 tcs that form eyes tend to do so within 48 h of the cyclone s reaching tropical storm strength this suggests the existence of an opportune time window during which a tc can readily form an eye from the leng

aggregate stability in range sandy loam soils relationships with runoff and erosion abstract the spatial variability of soil aggregate stability and its relationship to runoff and soil erosion were examined in a catena of soils and vegetation in a semiarid environment at the rambla honda field site tabernas almeria se spain to evaluate the validity of structural stability as a soil erosion indicator in sandy loam range soils the influence of soil properties and topography on the variability of aggregate stability was also examined methods include 1 aggregate stability assessment at 12 sites 3 repetitions per site on the hillslope by two methods a aggregate size distribution by dry sieving b water drop test 2 soil organic carbon content 3 particle size distribution determination 4 terrain attributes derived from a digital elevation model 1 m resolution 5 monitoring runoff and erosion for nearly 3 years in eight 10 2 m plots distributed over the hillslope results 41 of the average soil mass is formed by 2 mm aggregates however wet aggregate stability is poor with a mean of a total of 1440 aggregates of only 26 drop impacts necessary to break up a wet aggregate pf 1 significant relationships were found in the number of water drops required for aggregate breakdown and runoff and erosion rates however no significant relationships between the mean weight diameter of aggregates under dry conditions and runoff or erosion rates were observed the relationships of aggregates with other soil properties hillslope position and proximity to plants are also analysed the most significant correlation found was between the number of drop impacts and soil organic matter content the stability of topsoil aggregates seems to be a valuable indicator of field assessed runoff and inter rill erosion of sandy loam range soils under semiarid conditions

using an object based approach to quantify the spatial structure of reflectivity regions in hurricane isabel 2003 part i comparisons between radar observations and model simulations abstractwhen a hurricane undergoes extratropical transition et its rainbands evolve from a circular and compact shape to a more elongated fragmented and dispersed configuration with an exposed circulation center this study calculates five metrics to measure these spatial changes in reflectivity regions as hurricane isabel 2003 underwent et a mosaic of observations from the weather surveillance radar 1988 doppler wsr 88d network is compared to reflectivity simulated by the advanced research weather research and forecasting wrf arw model six simulations are performed by varying the cumulus and microphysics parameterizations to produce a range of reflectivity configurations a bias correction is applied to model simulated reflectivity prior to the calculation of spatial metrics because lower reflectivity values are generally underrepresented while higher values are generally overrepresented however the simulation with kain fritsch cumulus and morrison two moment microphysics overpredicts ref

reexamining the near core radial structure of the tropical cyclone primary circulation implications for vortex resiliency abstract recent theoretical studies based on vortex rossby wave vrw dynamics have established the importance of the radial structure of the primary circulation in the response of tropical cyclone tc like vortices to ambient vertical wind shear linear vrw theory suggests in particular that the degree of broadness of the primary circulation in the near core region beyond the radius of maximum wind strongly influences whether a tilted tc vortex will realign and resist vertical shear or tilt over and shear apart fully nonlinear numerical simulations have verified that the vortex resiliency is indeed sensitive to the initial radial structure of the idealized vortex this raises the question of how well the true nature of a tc s primary circulation is represented by idealized vortices that are commonly used in some theoretical studies in this paper the swirling wind structure of tcs is reexamined by utilizing flight level observations collected from atlantic and eastern pacific storms during 1977 2

relationships between tropical cyclone intensity and eyewall structure as determined by radial profiles of inner core infrared brightness temperature abstractradial profiles of infrared brightness temperature for 2405 different satellite observations from 14 western north pacific tropical cyclones tcs from the 2012 season were analyzed and compared to intensity and changes in intensity four critical points along the inner core of each infrared ir brightness temperature bt profile were identified coldest cloud top cct first overshooting top fot and lower l45 and upper u45 extent of the inner eyewall radial movement of the mean cct point outward with increasing tc intensity combined with subsequent warming of the mean l45 point with intensity highlighted structure changes that are consistent with eye and eyewall development when stratified by latitude and vertical wind shear the cct point moved radially outward for all cases notably at higher intensities for lower latitude tcs and at lower intensities for higher latitude tcs the majority of the warming of the l45 point with increasing intensity occurred for low latitude and low s

archaeopedology and chronostratigraphy of colluvial deposits as a proxy for regional land use history baar southwest germany abstract soils are the basis of our food production supplying plants with nutrients and water farming leaves traces in the soil because cultivation can cause soil erosion one result is the formation of colluvial deposits which can be used as geoarchives of past human impacts on their terrestrial environment the present study combines pedological and archaeological knowledge with chronostratigraphic analyses to infer deposition phases of colluvial material thereby allowing the reconstruction of past land use and settlement activities in the baar region sw germany local colluvial signals are interpreted as a regional proxy for increased soil erosion and colluviation on the baar seven main deposition phases of colluvial material can be detected by 28 luminescence dates and 41 radiocarbon ages distributed through 26 soil profiles our results indicate increased colluviation in the younger neolithic 3800 bce the early to middle bronze age 1550 bce the iron age 500 bce the roman empire 100 ce and from the high middle ages onwards 1200 ce 1300 ce 1600 ce these dates and record of colluviation complement archaeological knowledge of the fundamental impact of human activities on the landscape due to sedentism and agriculture early anthropogenic hypothesis our study shows that most periods of intensified colluvial deposition often but not always date to times with colder more humid climatic periods the spatial and temporal correlation of main depositional phases with archaeological finds points to land use as the determining factor of colluvial deposition at least since roman times

reexamining the vertical structure of tangential winds in tropical cyclones observations and theory a few commonly held beliefs regarding the vertical structure of tropical cyclones drawn from prior studies bothobservationalandtheoretical areexaminedinthisstudy oneofthesebeliefsisthattheoutwardslopeof the radius of maximumwinds rmw is a function of the size of the rmw another belief is that the outward slope of the rmw is also a function of the intensity of the storm specifically shea and gray found that the rmw becomes increasingly vertical with increasing intensity and decreasing radius the third belief evaluated here is that the rmw is a surface of constant absolute angular momentum m these three conventional wisdoms of vertical structure are revisited with a dataset of three dimensional doppler wind analyses comprising seven hurricanes on 17 different days azimuthal mean tangential winds are calculated for each storm andtheslopesofthermwandmsurfacesareobjectivelydetermined theoutwardslopeofthermw is shown to increase with radius which supports prior studies in contrast to prior results no relationship is found between the slope of the rmw and intensity it is shown that the rmw is indeed closely approximated by an m surface for the majority of storms however there is a small but systematic tendency for m to decrease upward along the rmw utilizing emanuel s analytical hurricane model a new equation is derived for the slope of the rmw in radius pressure space this predicts a linear increase of slope with radius and essentiallyno dependence of slope on intensity an exactly analogous equationcan be derivedin log pressure height coordinates and a numerical solution yields the same conclusions in geometric height coordinates these conclusions are further supported by the results of simulations utilizing emanuel s simple timedependent axisymmetric hurricane model as both the model and the analytical theory are governed by the dual constraints of thermal wind balance and slantwise moist neutrality it is demonstrated that it is these two assumptionsthat requirethe slope of the rmw to be a functionof its size but not of the intensityof the storm finally it is shown that within the context of emanuel s theory the rmw must very closely approximate an m surface through most of the depth of the vortex

paleohydraulic reconstruction of flash flood peaks from boulder deposits in the colorado front range nine watersheds in the colorado front range with steep bedrock channels were used to test the accuracy of paleohydraulic reconstruction of large flash floods using boulder deposits the nine basins consist of eight small ungauged basins ranging in size from 1 6 to 29 km2 and the big thompson river at the mouth of the big thompson canyon draining 790 km2 between 1923 and 1976 all nine basins had had one catastrophic flash flood the magnitude of which has been estimated by the conventional slope area method in each basin coarse boulder deposits of the large flash floods were identified and three axes of the five largest boulders were measured along with at least two profiles of the valley cross section a simple arithmetic average of two theoretical and two empirical relationships was used to estimate average flood velocity using boulder size and shape average depth was estimated as the arithmetic average of four values computed from the manning equation a regression equation for boulder size and unit stream power a relative smoothness equation and a modified shields relationship the appropriate flood width for the estimated average depth was found by iteration using the valley cross sections the paleohydraulic discharges thus computed generally underestimate conventional slope area discharge estimates on small streams by as much as 75 although the average amount is only 28 too low and the reconstructed discharge in one stream was 31 too large the big thompson river flood of 1976 was overestimated by 76 reasons for discrepancy in reconstructed peaks could include 1 the possibility that floods may have been able to move boulders larger than those available to be moved 2 overestimation of the slope area discharge because high water marks were set prior to erosion of the channel 3 underestimation of original roughness coefficients and 4 macroturbulent effects during fast deep flows the paleohydraulic technique is applied to two other streams in colorado with sedimentological evidence of large flash floods but no conventional indirect discharge estimates a small tributary to the big thompson river draining 1 8 km2 has a paleohydraulic reconstructed flood peak of about 60 m3 s from a flood in 1976 using boulders excavated from a foundation site in holocene alluvium along boulder creek in boulder colorado a paleohydraulic reconstructed flood peak of between 860 and 1 512 m3 s is calculated this is 1 4 to 2 4 times the magnitude of the estimated 500 yr flood

the kinematic structure of a hurricane with sea level pressure less than 900 mb abstract a national oceanic and atmospheric administration aircraft recorded the first doppler radar data in a tropical cyclone with a minimum sea level pressure mslp 50 m s 1 extended to 12 km higher than has been reported in previous hurricanes the inner eyewall contained weak

climatic control on palaeohydrology and cyclical sediment distribution in the plio quaternary deposits of the guadix basin betic cordillera spain abstract a cyclical pattern can be observed in the central sector of the guadix basin southern spain in the late pliocene quaternary alluvial fan deposits prograding into its axial valley a climatic significance has been attributed to this cyclicity on the basis of sedimentological and preliminary isotopic studies the progradation phases of the alluvial fans are here attributed to more arid time intervals in which the vegetation cover would be less developed erosion and sediment supply would be higher and base level would be lower in contrast the time intervals during which the fluvial system sediments dominated the area are inferred to be wetter and base level higher with vegetation cover retaining the soils and preventing erosion permanent water supply to the river would therefore facilitate the aggradation of the floodplain and prevent progradation of the fans starting from a litho bio and magnetostratigraphical frame provided for the area an age is assigned to the alternation of the reddish sediments of the transverse alluvial fans and the greyish to white fluvio lacustrine sediments of the axial drainage system a cyclicity of ca 100 ky has been identified in most of the alluvial fan progradation phases falling within milankovitch high frequency eccentricity periodicities correlation of the phases with insolation curves is accordingly discussed as a possible origin for the cyclicity finally the results offer new insights into early hominin occupation patterns in the region through the identification of predictable resources of permanent fresh water that would have remained available throughout the recorded time span that includes the early middle pleistocene transition even during times of aridification

shear relative asymmetries in tropical cyclone eyewall slope abstractrecent studies have analyzed the azimuthal mean slope of the tropical cyclone tc eyewall this study looks at the shear relative azimuthal variability of different metrics of eyewall slope the 20 dbz surface the radius of maximum wind rmw and an angular momentum m surface passing through the rmw the data used are doppler radar composites from the noaa hurricane research division hrd this study examines 34 tcs with intensities ranging from 3 to 75 m s 1 and shear magnitudes ranging from 0 to 10 m s 1 calculation of the mean slope in each quadrant for all cases shows that rmw slope has the strongest asymmetry with downshear slope larger than upshear in 62 of cases slopes of momentum surfaces and dbz surfaces are also greater downshear in some cases 65 for m and 47 for dbz but there is more variance than in the rmw slope the azimuthal phase of maximum slope occurs most often downshear particularly downshear left consistent with the depiction of a mean vortex tilt approximate

the evolution of hurricane danny 1997 at landfall doppler observed eyewall replacement vortex contraction intensification and low level wind maxima danny made landfall as a minimal hurricane on the alabama coast on 19 july 1997 after drifting over mobile bay for over 10 h danny s unusually close proximity to the doppler radar wsr 88d in mobile provided an unprecedented view of the storm s complex and dramatic evolution during a prolonged landfall event over a 1 day period base reflectivity and velocity products were combined with aircraft reconnaissance information to detail the formation of concentric eyewalls and complete evolution of an eyewall replacement cycle this highly symmetric hurricane then underwent a rapid asymmetric transition in mobile bay during which a small eyewall mesovortex developed adjacent to intense convection in the western eyewall radar estimated rainfall increased dramatically during the asymmetric phase rates exceeded 100 mm h21 for nine consecutive hours west of the center while precipitation nearly vanished to the east changes in the distribution of precipitation corresponded with changes in the low level wind velocity structure a 25 h temporal composite of wsr 88d base velocities displayed axisymmetric intensification and contraction of danny s core during the eyewall replacement cycle later the asymmetric phase was dominated by further contraction and intensification on the west side only in the western eyewall a persistent boundary layer wind maximum evolved and contracted to a radius of only 10 13 km from the center concurrently eastside boundary layer winds diminished as the maximum winds rose to 1 1 5 km altitude and the radius expanded danny reached maximum intensity during this asymmetric phase in mobile bay with base velocities 44 m s21 85 kt at 600 m elevation eyewall contraction in the meandering storm combined with climatologically elevated ssts in shallow mobile bay probably played significant roles in danny s continued intensification there discrepancies arose in determining danny s structural patterns intensity and evolution during landfall interpretation varied depending on the type of platform used to observe the storm the continual sampling of the storm by the nearby wsr 88d provided detail not available from aircraft data alone doppler base velocities in the intense westside convection were much stronger than measured at flight level yet the opposite was true in the storm s drier east side doppler radar showed that the westside base velocity maxima were confined to the boundary layer 600 700 m and represented a slightly conservative estimate of maximum surface gusts recorded at dauphin island during the passage of danny s convective eyewall thus winds probably were even stronger at boundary layer levels below the wsr 88d s lowest scan elevation the shallowness and persistence of danny s boundary layer velocity maxima stressed the need for accurate wind information in the lowest few hundred meters of a tropical cyclone s eyewall for a better indication of the storm s true intensity and near surface wind velocities

buoyancy of convective vertical motions in the inner core of intense hurricanes part ii case studies abstract this is the second of two papers on the buoyancy of convective vertical motions in the inner core of intense hurricanes this paper uses extensive airborne radar dropwindsonde and flight level observations in hurricanes guillermo 1997 and georges 1998 to illustrate typical azimuthal distribution of buoyant convection and demonstrate that the low level eye can be an important source region for buoyant eyewall convection in both hurricanes eyewall vertical velocity and radar reflectivity are asymmetric and exhibit persistent relationships with the direction of the environmental vertical wind shear mesoscale vertical motions exhibit a wavenumber 1 structure with maximum ascent downshear and weak descent upshear the mesoscale reflectivity maxima are located left of shear buoyant eyewall updraft cores and transient convective scale reflectivity cells are predominantly downshear and left of shear most eyewall downdraft cores that transport significant mass downward are located upshear nega

miniature supercells in an offshore outer rainband of hurricane ivan 2004 abstract airborne doppler radar observations are used to document the structure of three miniature supercells embedded in an outer rainband of hurricane ivan on 15 september 2004 the cells were located more than 100 km offshore beyond the doppler range of coastal radars the combination of large cape large vertical wind shear and moderate cell relative helicity with an apparent midlevel dry air intrusion provided an offshore environment supporting rotating storms each shallow cell contained a 5 7 km diameter mesocyclonic updraft with midlevel updraft and vorticity maxima that exceeded 6 m s 1 and 0 008 s 1 respectively such offshore structures are consistent with miniature supercells observed onshore in association with tropical cyclone tornado outbreaks the strong updrafts resulted from a combination of kinematic convergence thermal instability and shear induced vertical perturbation pressure gradients mesocyclone production largely resulted from the tilting and subsequent stretching of low l

tropical cyclone kinematic structure retrieved from single doppler radar observations part i interpretation of doppler velocity patterns and the gbvtd technique abstract deducing the three dimensional primary circulation of landfalling tropical cyclones tcs from single ground based doppler radar data remains a difficult task the evolution and structure of landfalling tcs and their interactions with terrain are left uncharted due to the lack of dual doppler radar observations existing ground based single doppler radar tc algorithms provide only qualitative information on axisymmetric tc center location and intensity in order to improve understanding of the wind structures of landfalling tcs using the widely available wsr 88d data along the u s coastal region a single ground based radar tc wind retrieval technique the ground based velocity track display gbvtd technique is developed part i of this paper presents 1 single doppler velocity patterns of analytic asymmetric tcs 2 derivation of the gbvtd technique and 3 evaluation of the gbvtd retrieved winds using analytic tcs the doppler velocity patterns of asymmetric tcs display more complex structu

landscape related transformation and differentiation of chernozems catenary approach in the silesian lowland sw poland abstract the unfavourable environmental conditions to chernozem development in central europe has led to questions regarding their origin and age and conditions necessary for chernozem persistence in central europe under a humid climate this paper deals with chernozem transformation during the holocene period in sw poland in relation to land morphology the study was based on a catenary approach with additional remarks on parent material homogeneity and soil classification based on textural and geochemical indices the homogeneity of aeolian material loess was proven in the main part of the catena which confirmed that the differentiation of dry and wet chernozemic soil across the catena did not result from the variability of parent material no differences in morphological or physicochemical characteristics of mollic horizons were identified between the well drained and wet sections of the catena the strong redoximorphic features manifested as stagnic or gleyic properties in the lowermost part of catena are therefore secondary features i e developed after the mollic horizon development presumably in late holocene period chernozems with chernic horizon weakly developed subsurface argic horizon and free of redoximorphic features prevail in the central well drained and not eroded section of the catena it has been hypothesized that the loess soils in the uppermost more inclined part of the catena have been truncated by erosion during the first agricultural period then afforested and transformed into luvisols probably due to temporary abandonment of those sites less favourable for farming the soils in the transitional zone received the colluvial addition of humus material from the eroded hill summit however the colour of the humus layer has a chroma too high for a chernic horizon that surprisingly shifted these soils to the kastanozems group this study showed that the direction of transformation of native chernozems in the holocene period was strongly related to their position in the landscape which affected the erosion accumulation intensity and water drainage conditions soil moisture regime as a final result of these transformations a relief related zonality of soils has developed with stagnic gleyic chernozems luvic chernozems colluvial kastanozems haplic luvisols in the lower moist middle well drained and upper colluvial eroded sections of the undulating loess plain respectively

eye and eyewall traits as determined with the noaa wp 3d lower fuselage radar abstracteye and eyewall traits were ascertained for 209 images from 37 tropical cyclones tcs using the lower fuselage 5 6 cm radar aboard the two national oceanic and atmospheric administration wp 3ds these tcs were almost entirely from the atlantic basin and were sampled from 1997 to 2012 for the eye these traits included area maximum diameter and roundness for the eyewall the traits included area completeness maximum width maximum reflectivity value and location number of local reflectivity maxima and mean rain rate these variables were compared to tc intensity and motion characteristics from the best track dataset and environmental characteristics from the statistical hurricane intensity prediction scheme interrelationships between eyewall features revealed that eyewall reflectivity features became more homogeneous as eye and eyewall areas shrank and maximum reflectivity and rain rate increased as the eyewall became wider and more complete as the tc intensified the eye area decreased

surface pressure features of landfalling typhoon rainbands and their possible causes abstract this study uses temporally high resolution surface observations doppler radar and micro rain radar to document the finescale features of the two landfalling rainbands associated with typhoon longwang 2005 as they passed over northern taiwan the present case allows a unique opportunity to investigate well defined convectively active tropical cyclone rainbands over land in particular the surface pressure fluctuations observed during the passage of the two rainbands and their possible causes are explored the rainbands were predominantly convective in nature with embedded stratiform precipitation outside their inner outer edge analyses of surface observations show similar surface pressure fluctuations during the rainband s passage low high pressure with relatively strong weak cross band flow and warmer colder temperature was located inside the outer inner edge maximum minimum pressure perturbations were observed to be 1 5 1 mb with smaller magnitudes 0 4 mb outside th

temporal and spatial evolution of an on land hurricane observed by seismic data 2014 american geophysical union all rights reserved a dense seismic array can provide new perspectives for a decaying hurricane after its landfall the case of hurricane isaac in 2012 is presented using a seismic array from earthscope usarray the amplitude distance plots from the center of the hurricane showed a sharp peak at a distance of 75 km at the time of landfall this peak decayed and moved outward from the center over the next 1 5 days the sharp peak can be explained by strong surface pressure fluctuations under the eyewall in which a focused ascending flow is known to exist we reconstructed the time evolution of surface pressure that explains seismic data pressure solutions indicate that the eyewall stayed at 75 km in the first 10 h after the landfall while the ascending flow weakened significantly in the following 24 h the eyewall diffused and moved to distances about 200 300 km suggesting its collapse during this period key points hurricane eyewall can be studied from seismic amplitude versus distance plotsseismically derived surface pressure shows the location and strength of eyewalltime evolution of this decaying process can be tracked

influence of bedrock structures on the spatial pattern of erosional landforms in small alpine catchments structural settings and lithological characteristics are traditionally assumed to influence the development of erosional landforms such as gully networks and rock couloirs in steep mountain rock basins the structural control of erosion of two small alpine catchments of distinctive rock types is evaluated by comparing the correspondences between the orientations of their gullies and rock couloirs with 1 the sliding orientations of potential slope failures mechanisms and 2 the orientation of the maximum joint frequency this latter being considered as the direction exploited primarily by erosion and mass wasting processes these characteristic orientations can be interpreted as structural weaknesses contributing to the initiation and propagation of erosion the morphostructural analysis was performed using digital elevation models and field observations the catchment comprised of magmatic intrusive rocks shows a clear structural control mostly expressed through potential wedges failure such joint configurations have a particular geometry that encourages the development of gullies in hard rock e g through enhanced gravitational and hydrological erosional processes in the catchment underlain by sedimentary rocks penetrative joints that act as structural weaknesses seem to be exploited by gullies and rock couloirs however the lithological setting and bedding configuration prominently control the development of erosional landforms and influence not only the local pattern of geomorphic features but the general morphology of the catchment the orientations of the maximum joint frequency are clearly associated with the gully network suggesting that its development is governed by anisotropy in rock strength these two catchments are typical of bedrock dominated basins prone to intense processes of debris supply this study suggests a quantitative approach for describing the relationship between bedrock jointing and geomorphic features geometry incorporation of bedrock structure can be relevant when studying processes governing the transfer of clastic material for the assessment of sediment yields and in landforms evolution models

structural changes of an outer tropical cyclone rain band encountering the topography of northern taiwan this study utilized ground based doppler radar observations to document the detailed structures of an outer tropical cyclone rainband tcr of typhoon longwang 2005 as the rainband passed over the topography of northern taiwan on 1 october 2005 the tcr was oriented northeast southwest and was roughly parallel to the mountain barrier with a higher lower terrain height in its southern northern landfalling segment during the pre landfall stage the tcr was characterized by convective precipitation on its inner side where the front to rear flow met with the rear to front flow to lift air upward with overturning updraft like signatures significant relatively minor changes in the tcr s structures were evident in the southern northern landfalling segment during the landfalling stage in particular the southern landfalling segment exhibited a much stronger front to rear flow that passed through the region of the rainband resulting in the absence of low level organized convergence and a relatively disorganized nature of precipitation this structural change was shown to be closely related to a significant decrease in the cross barrier flow due to the orographic blocking that occurred as easterly ambient winds encountered local high mountains in the vicinity of the rainband segment as the tcr propagated over the western side of the major topography the low level rear to front flow reappeared due to the collapse of low level orographic blocking and the convergence between the front to rear flow and the rear to front flow tended to rebuild a well organized convective circulation along the rainband results from this case study provide insight into processes that contribute to rapid structural changes in a landfalling tcr over mountainous regions

storage dynamics in hydropedological units control hillslope connectivity runoff generation and the evolution of catchment transit time distributions we examined the storage dynamics and isotopic composition of soil water over 12 months in three hydropedological units in order to understand runoff generation in a montane catchment the units form classic catena sequences from freely draining podzols on steep upper hillslopes through peaty gleys in shallower lower slopes to deeper peats in the riparian zone the peaty gleys and peats remained saturated throughout the year while the podzols showed distinct wetting and drying cycles in this region most precipitation events are 80 of flow even in large events reflecting the displacement of water from the riparian soils that has been stored in the catchment for 2 years these riparian areas are the key zone where different source waters mix our study is novel in showing that they act as isostats not only regulating the isotopic composition of stream water but also integrating the transit time distribution for the catchment

unravelling fluvial deposition and pedogenesis in ephemeral stream deposits in the vicinity of the prehistoric rock shelter of ifri n ammar ne morocco during the last 100 ka abstract our study focuses on the ephemeral stream deposits of wadi selloum to identify phases of morphodynamic stability pedogenesis and activity flooding in the direct vicinity of the rock shelter of ifri n ammar ne morocco as one of the oldest settlement sites of anatomically modern humans amh in north africa ifri n ammar documents periodical occupations since 170 ka since the discontinuous settlement record may reflect climate forcing with subsequent landscape changes we aim at reconstructing the palaeoenvironmental variability recorded in the ephemeral stream deposits in addition to the use of micromorphological sedimentological geochemical and mineralogical methods the geochronological framework of ephemeral stream deposits was established by the application of different luminescence dating techniques the deposition ages between 102 8 ka and 1 3 0 2 ka span different morphodynamically stable and active phases periods of enhanced aggradation occurred around 100 ka 75 ka 55 ka after the lgm and during the holocene whilst sedimentation ended after 1 3 ka the wadi selloum might be characterised by enhanced flooding during humid phases pedogenesis may be used as environmental indicator for more humid climate conditions during mis 3 palaeo calcisol the early holocene calcisol and the late holocene fluvisol this study thus provides first insights into the palaeoenvironmental changes around the rock shelter of ifri n ammar during the last glacial interglacial cycle

the marm spatially distributed soil evolution model a computationally efficient modeling framework and analysis of hillslope soil surface organization 1 hillslope surface armouring and weathering processes have received little attention in geomorphologic and hydrologic models due to their complexity and the uncertainty associated with them their importance however in a wide range of spatial processes is well recognized a physically based armouring and weathering computer model armour has previously been used to successfully simulate the effect of these processes on erosion and soil grading at a hillslope scale this model is however computationally complex and cannot realistically be applied over large areas or over long periods of time a simplified process conceptualization approach is presented named marm which uses a novel approach of modeling physical processes using transition matrices which is orders of magnitude faster we describe in detail the modeling framework we calibrate and evaluate the model against armour simulations and show it matches armour for a range of conditions the computational efficiency of marm allowed us to easily examine time and space varying relationships between erosion and physical weathering rates at the hillslope scale for erosion dominated slopes the surface coarsens over time while for weathering domination the surface fines over time when erosion and weathering are comparable in scale a slope can be weathering dominated upslope where runoff and therefore erosion is low and armouring dominated downslope in all cases for a constant gradient slope the surface armour coarsens downslope as a result of a balance between erosion and weathering thus even for weathering dominated slopes the surface grading catena is dependent on armouring through the balance between weathering and armouring we also observed that for many slopes the surface initially armours but after some period of time space and rate dependent weathering begins to dominate and the surface subsequently fines depending on the relative magnitude of armouring and weathering the final equilibrium grading of the slope may be finer or coarser than the initial conditions the results demonstrate the complexity of the evolution of surface grading and the balance between the armouring and weathering processes they also point toward inherent organization of surface grading on the hillslope driven by erosion even for extremely high weathering rates the implications for natural landforms are discussed we also plot and quantify for the first time a log log relationship between surface grading contributing area and slope for a range of weathering rates the results show that this log log relationship is robust the log log scaling is constant in space and true even for extreme weathering rates this has potentially important implications for soil geomorphology it suggests that an analytical solution can be found for soil grading catena this might allow us to more easily map soil distribution as a function of topographic characteristics

high resolution numerical simulation of a polar low 1 the first high resolution simulation of an observed polar low using a non hydrostatic mesoscale numerical model with 2 km horizontal resolution is reported the case studied is a remarkable polar low that developed over the japan sea on 21 january 1997 the simulation successfully reproduced the observed features of the polar low such as its horizontal scale movement spiral bands a cloud free eye and cloud streets associated with the cold air outbreak detailed three dimensional structures of the simulated polar low which are difficult to observe by in situ measurement have been clarified and its development mechanism is discussed

buoyancy of convective vertical motions in the inner core of intense hurricanes part i general statistics abstract the buoyancy of hurricane convective vertical motions is studied using aircraft data from 175 radial legs collected in 14 intense hurricanes at four altitudes ranging from 1 5 to 5 5 km the data of each leg are initially filtered to separate convective scale features from background mesoscale structure convective vertical motion events called cores are identified using the criteria that the convective scale vertical velocity must exceed 1 0 m s 1 for at least 0 5 km a total of 620 updraft cores and 570 downdraft cores are included in the dataset total buoyancy is calculated from convective scale virtual potential temperature pressure and liquid water content using the mesoscale structure as the reference state core properties are summarized for the eyewall and rainband regions at each altitude characteristics of core average convective vertical velocity maximum convective vertical velocity and diameter are consistent with previous studies of hurricane convection most cores are superi

airborne doppler observations of a landfalling cold front upstream of steep coastal orography abstract this study uses airborne doppler radar observations to describe the mesoscale structure and evolution of a cold frontal system as it made landfall on the mountainous coast of oregon and northern california on 1 december 1995 during the coastal observations and simulations with topography experiment this section of coastline constitutes a steep approximately two dimensional north south oriented orographic barrier the front exhibited a northeast southwest orientation and thus intersected the axis of high terrain at an acute angle the along barrier pressure gradient and low level winds increased with time along the coastal zone and reached a maximum as the front made landfall stably stratified prefrontal flow was strongly blocked by the orography resulting in a confluent transition from pervasive southwesterly winds offshore to a narrow zone of accelerated south southwesterly flow near the coast where wind speeds approached 30 m s 1 at a height of 750 m above mean sea level postfrontal flow

soil evolution indices in fluvial terrace chronosequences from central spain tagus and duero fluvial basins abstract soil development in central spain was studied through analysis of soil chronosequences from tagus and duero river valley terrace systems evolved under similar mediterranean climatic conditions throughout the pleistocene the most complete soil terrace sequence representative for our study developed in the tagus valley aranjuez toledo talavera sector we present soil textural data for argillic horizons developed in late to early pleistocene soils from five valleys we derive soil development indices from clay and silt content and thickness of argillic horizons global clay content gcc clay content cc and clay silt ratio c si ratio numerical indices related to clay illuviation reflect soil evolution explored by multiple regression of soil terrace height and soil age relative terrace heights above present river thalwegs i e 100 m were transformed to ages with a height age transfer function on the basis of preliminary statistical geochronological analyses for central spain the height age transfer function a 3rd order polynomial r 2 0 90 based on 60 published numerical ages and paleomagnetic data for terrace sequences describes the overall trend of valley downcutting for the last c 2 ma in central spain it assigns numerical ages to terrace levels at different relative elevations and gives an estimate of standardized ages for the related soils the explored age soil relationships logarithmic functions r 2 0 80 are sensitive to parent material clay content corresponding to geology of river catchments for most soil indices only the clay silt ratio minimizes this sensitivity and can thus be used for regional approaches tagus and duero basins central spain whereas the cc index is applicable only to individual river valleys or different river valleys with similar catchment geology i e tagus basin the c si ratio illustrates the logarithmic trend of weathering of soil particles into clay over time the generation of soil textural balances sustaining illuviation processes and therefore provides an estimate of soil ageing for the implementation of soil chronofunctions for regional analysis of river valleys evolving in similar climatic conditions and with similar base level history

two distinct regimes in the kinematic and thermodynamic structure of the hurricane eye and eyewall abstract using aircraft flight level data the present work demonstrates that the kinematic and thermodynamic distributions within the eye and eyewall of strong hurricanes are observed to evolve between two distinct regimes in the first regime angular velocity is greatest within the eyewall and relatively depressed within the eye in the second regime radial profiles of angular velocity are nearly monotonic with maxima found at the eye center considering sequential profiles within individual hurricanes the authors find that the evolution of the kinematic distribution is often marked by a transition from the first regime to the second the transition can occur in less than 1 h also noted during the transition are dramatic changes in the thermodynamic structure of the hurricane prior to the transition regime 1 the eye is typically very warm and dry and the equivalent potential temperature is often elevated within the eyewall and relatively depressed within the eye after the transition regime 2

observed boundary layer wind structure and balance in the hurricane core part i hurricane georges abstract the gps dropsonde allows observations at unprecedentedly high horizontal and vertical resolution and of very high accuracy within the tropical cyclone boundary layer these data are used to document the boundary layer wind field of the core of hurricane georges 1998 when it was close to its maximum intensity the spatial variability of the boundary layer wind structure is found to agree very well with the theoretical predictions in the works of kepert and wang in particular the ratio of the near surface wind speed to that above the boundary layer is found to increase inward toward the radius of maximum winds and to be larger to the left of the track than to the right while the low level wind maximum is both more marked and at lower altitude on the left of the storm track than on the right however the expected supergradient flow in the upper boundary layer is not found with the winds being diagnosed as close to gradient balance the tropical cyclone boundary layer model of kepert and wan

catena linking of landscape geochemical processes and reconstruction of pedosedimentogenesis a case study of defensive constructions of the mid 17th century south russia abstract the catena concept along with previously proposed meanings of this term has recently acquired a soil evolutionary content the prospects of wider special and chronological study of dated pedotopocatenas include the possibility of a more detailed analysis of the mutual dependence of soil geomorphological relationships through distinguishing relatively homogeneous climatic stages of pedogenesis and denudation with this purpose the present study comprised earthen defensive constructions which within the rampart ditch system combine erosive trans accumulative catenas and accumulators of pedolithosediments the goal was to develop a system of the most information rich pedogenetic indicators to reconstruct the dynamics of erosion accumulative processes on the basis of dated earthen defensive constructions of a historical period using the example of a frontier rampart within a ditch from the mid 17th century soil samples were collected within the limits of the erosion and trans accumulative catenas as well as in the closing alignment of the ditch over the vertical profile in eight strata of pedosediments of up to 1 m high the granulometric composition concentration of macroelements and trace elements 25 metals and oxides in soils and in particles with sizes 0 01 mm in size the content of organic carbon and its qualitative composition the sum of the elements accumulated in the soil p ca k mg mn cu as well as the geochemical ratios which reflect the processes of leaching can serve as palaeogeographic tracers of the climatic variability at the level of intra secular changes under forest steppe conditions the history of the formation of pedosediments over 3 5 centuries in the forest steppe zone of eastern europe comprises two wet periods 1890 1935 1976 2013 when the average annual rates of pedosedimentogenesis were similar 2 80 2 85 mm yr 1 and two periods of geomorphological lull and a xeromorphic climatic condition span 1821 1890 and 1666 1741 these periods correspond to diminution of the average rate of accumulation of sediments down to 2 47 mm yr 1 the results of the present study suggest the need for purposeful research and wide inclusion of dated sites of the anthropogenic relief formation with flow geochemical series over the topographic gradient into studies of soil geomorphologic interrelations and calibration of mathematic models of natural processes using on site data

effect of snow amount on runoff soil loss and suspended sediment during periods of snowmelt in southern west siberia abstract surface runoff soil loss suspended sediment concentration ssc texture of eroded soils and suspended sediment were determined on slightly eroded chernozems mouldboard fall ploughed during years with different amounts of snow in three areas of southern west siberia predsalairye priobye and kuznetsk hollow these areas have different geomorphological and climatic characteristics and soils observations were made from 1969 to 2007 the soil loss during very low snow and low snow years did not exceed 2 t ha 1 after winters with normal amounts of snow the runoff led to slight soil loss 2 5 t ha 1 soil losses in high snow and very high snow years varied from slight to severe 4 8 15 8 t ha 1 depending on studied area the main sediment exported during intensive snowmelt and the 1 mm of runoff transported from 35 to 150 kg ha 1 of soil material the removal of soil particles

the garden city kansas storm during vortex 95 part i overview of the storm s life cycle and mesocyclogenesis abstract analysis of a supercell storm that produced an f1 tornado near garden city kansas is presented this event provided one of the first opportunities to synthesize data collected by a new airborne radar platform called eldora electra doppler radar developed by the national center for atmospheric research the early stages of development of the midlevel mesocyclone and the entire evolution of the low level mesocyclone are captured over a 70 min period the low level mesocyclone began as an incipient shallow circulation along a synoptic scale trough the circulation intensified and grew in depth via vortex stretching under the influence of a strong updraft as this rotation built up from the boundary layer it initially remained separate and distinct from the midlevel mesocyclone subsequently the two mesocyclones merge to produce a single column of rotation 4 5 km in diameter an occlusion downdraft develops within the mesocyclone circulation during the last passes by the storm signaling the beg

reflectivity ice scattering and lightning characteristics of hurricane eyewalls and rainbands part i quantitative description abstract covering december 1997 through december 1998 261 overpasses of 45 hurricanes by the tropical rainfall measuring mission trmm satellite are used to document the observed radar reflectivity values passive microwave ice scattering magnitudes and total lightning cloud to ground plus in cloud these parameters are interpreted as describing convective vigor or intensity with greater reflectivities particularly aloft greater ice scattering lower 85 and 37 ghz brightness temperatures and increased lightning frequency indicating more intense convection for each parameter the full distribution of values observed during the trmm satellite s first year is presented for specific regions properties of three regions of the hurricane eyewall inner rainband and outer rainband are treated separately and compared to other tropical oceanic and tropical continental precipitation systems reflectivity profiles and ice scattering signatures are found to be fairly similar for both hurricane and non

historical erosion and sedimentation in two small watersheds of the southern blue ridge mountains north carolina usa sediment bodies produced during historical periods of human land use sometimes referred to as legacy sediment may be found in various locations within drainage basins and potentially remobilized by hydrogeomorphic processes accompanying land use change the amounts and locations of stored legacy sediment can be significant factors in modern drainage basin function and should be accounted for when possible in this study late nineteenth century erosion and sediment storage were investigated and used to construct approximate sediment budgets for two small blue ridge mountain drainage basins in north carolina usa erosion was quantified using a distributed implementation of the universal soil loss equation usle and calibrated on the separate bases of soil profile truncation data and recent published rates for long term erosion in the region sediment yield information was reconstructed from pond sediments trapped behind a mill dam alluvial sediment storage was quantified using field studies of streambank and floodplain sediment profiles and digital elevation data colluvial storage was calculated as a residual in the sediment budget and further evaluated using soil profile studies of footslope deposits and soil survey maps the proportions of erosion accounted for by the different budget terms in the most reliable budget are 28 sediment yield i e a sediment delivery ratio of 0 28 69 colluvial storage and 3 alluvial storage blue ridge basins with low levels of ground disturbance erode like piedmont basins at high levels of ground disturbance primarily due to higher slope angles sediment delivery ratio is high relative to those given for much larger basins in the adjacent and more frequently studied piedmont province and generally in accordance with published sediment delivery curves that reflect higher hydrogeomorphic connectivities within smaller basins low values for alluvial storage in blue ridge basins may be explained by high sediment transport within steep channels colluvial storage values have high uncertainties because of the well known problem of error accumulation in residual budget terms field data on colluvial deposits reported here are not sufficient to correct for this problem and in general the acquisition of accurate field data on historical colluviation remains an important methodological issue in historical sediment budgeting

single doppler radar observation of the concentric eyewall in typhoon saomai 2006 near landfall 1 landfalling typhoon saomai 2006 was observed by the cinrad wsr 98d radar on the southeast coast of china this study documents the formation and evolution of a concentric eyewall episode using the axisymmetric circulation derived from the ground based velocity track display technique saomai s outer eyewall formed after reaching its peak intensity 5 hours before landfall updraft tangential wind maximum and shallow low level inflow coincided with the high reflectivity and voriticity ring in both inner and outer eyewalls surrounding a moat region characterized by weak downward motion and lower reflectivity the subsidence and rain free moat region between the two eyewalls was filled with rain and upward motion prior to landfall indicating a breakdown in the outer eyewall which was a barrier to radial inflow meanwhile the outer vorticity maximum flattened and the central pressure dropped 9 hpa the eyewall replacement cycle didn t complete probably due to the landfall

the wake south of the alps dynamics and structure of the lee side flow and secondary potential vorticity banners the dynamics and structure of the lee side flow over the po valley during a northerly fohn event which occurred in the framework of the mesoscale alpine programme special observation period on 8 november 1999 during intensive observation period 15 has been investigated using aircraft data and high resolution numerical simulations numerical simulations were performed with the mesoscale non hydrostatic model meso nh using three nested domains with horizontal resolutions 32 8 and 2 km the 2 km resolution domain being centred on the po valley the basic data model comparison and back trajectory and tracer release analyses provided evidence that the jet wake structure of the flow above the po valley could be reasonably identified with the mountain pass peak distributions measurements from three aircraft flying below the alps crestline at 2700 1500 and 600 m above sea level along two 350 km east west legs designed to be approximately perpendicular to the northerly synoptic flow were used to compute the potential vorticity pv experimentally assuming the lee side flow to be two dimensional the simplified form of the pv under these assumptions is hereafter referred to as spv due to increasing lee side flow curvature with decreasing altitude caused by flow splitting at the scale of the alps the experimentally derived spv was compared to its simulated counterpart in situ measurements showed that coherent secondary pv banners pvb2s do exist downstream of the complex alpine terrain as observations show oscillations between positive and negative values of spv as expected from the simulations the details of the structure of the spv field simulated with meso nh were found to be different from the observations i e the location of observed maxima and minima of spv did not match their simulated counterparts at particular points this is because the correspondence between observed and modelled velocity and potential temperature fields was not good enough to expect good correspondence between differentiated quantities such as vorticity and potential temperature gradient since less reliable shorter scale features are thereby accentuated parametrized processes such as surface drag and internal diffusion and numerical processes such as model filters to which pv production mechanisms are sensitive and whose role is difficult to assess also contribute to the poor agreement between observed and modelled spv fluctuations finally simulations suggest that lowlevel gravity wave breaking was the main mechanism responsible for the formation of the elongated pvb2 modelled observed over the po valley

landscape evolution space and the relative importance of geomorphic processes and controls abstract the concept of landscape evolution space les is introduced as a tool for assessing landscapes and geomorphic systems intended to be a systematic means for assessing the various factors that contribute to the potential for change in geomorphic systems the les conceptual model is based on the energy and mass available to drive and accommodate landscape evolution an n dimensional landscape evolution space is defined not only by spatial coordinates but also by the availability of mass and energy the les is thus a space or hypervolume representing the resources available for geomorphic evolution and landscape change an expression for les is derived based on elevation material density surface area and inputs of solar meteoric and biological energy and mass though primarily an heuristic device the les model can be used to address concrete problems two examples are given in one increased surface area due to topographic roughening and dissection of an incised plateau is found to only slightly offset erosional removals of mass in terms of the magnitude of the les in the other sensitivity of coastal plain rivers to several impacts of sea level and climate change is explored the les model also leads to the concept of a geomorphological niche representing the resources available to drive or support a specific process or suite of processes considerations of landscape evolution have traditionally focused on the interplay of endogenic vs exogenic processes uplift vs denudation or soil formation vs erosion the les model explicitly broadens the conceptual framework of landscape evolution beyond the traditional dialectics

warm core formation in tropical storm humberto 2001 at 0600 utc 22 september 2001 humberto was a tropical depression with a minimum central pressure of 1010 hpa twelve hours later when the first global positioning system dropwindsondes gps sondes were jettisoned humberto s minimum central pressure was 1000 hpa and it had attained tropical storm strength thirty gps sondes radar from the wp 3d and in situ aircraft measurements are utilized to observe thermodynamic structures in humberto and their relationship to stratiform and convective elements during the early stage of the formation of an eye the analysis of tropical storm humberto offers a new view of the pre wind induced surface heat exchange pre wishe stageoftropicalcycloneevolution humbertocontainedamesoscaleconvectivevortex mcv similar to observations of other developing tropical systems the mcv advects the exhaust from deep convection in the form of an anvil cyclonically over the low level circulation center on the trailing edge of the anvilanareaofmesoscaledescentinducesdryadiabaticwarmingin thelowertroposphere thenascentwarm core at low levels causes the initial drop in pressure at the surface and acts to cap the boundary layer bl as bl air flows into the nascent eye the energy content increases until the energy is released from under the cap on the down shear side of the warm core in the form of vigorous cumulonimbi which become the nascent eyewall this series of events show one possible path in which a mesoscale convective system may evolve into a warm cored structure and intensify into a hurricane

heavy metals in surface sediments of the continental shelf of the south yellow sea and east china sea sources distribution and contamination the heavy metals in surface sediments of the continental shelf of the south yellow sea sys and the east china sea ecs collected in 2016 were analyzed to assess the heavy metal distributions contamination status and likely sources the metal concentrations generally met the china marine sediment quality criteria however the enrichment factor and geoaccumulation index values clearly showed elevated cd and pb concentrations in the region cd and pb contamination occurred mostly to the southwest of the changjiang river mouth and to the east of the shandong peninsula because of rapid economic and industrial development the results are likely to be useful for authorities responsible for sustainable coastal zone management

a diagnostic study of the intensity of three tropical cyclones in the australian region part i a synopsis of observed features of tropical cyclone kathy 1984 abstract objective streamline analyses and digitized high resolution ir satellite cloud data have been used to examine in detail the changes in the environmental circulation and in the cloud structure that took place in and around tropical cyclone kathy 1984 when it started to intensify and during its intensification and dissipation stages the change of low level circulation around tropical cyclone kathy was measured by the change in the angle of inflow 4 at a radius of 4 latitude from the cyclone center when kathy started to intensify 4 increased suddenly from 20 to 42 5 in the northerly airstream to the north and northeast of the depression and decreased to 0 to the south of the depression at that stage the low level circulation around the depression appeared as a giant swirl that started some 600 km to the north and northeast of the depression and spiraled inward toward its center while trade air which is usually cool dry and stable did not enter the cyclonic circulation the angle