variations of the east asian jet stream and asian pacific american winter climate anomalies in this study the authors apply the ncep ncar reanalysis and other observations to depict the association of the asian pacific american climate with the east asian jet stream eajs with an emphasis on boreal winter seasons and on interannual timescales they analyze the variations of the eajs and their relationships with el nino southern oscillation enso and extratropical north pacific sea surface temperature sst and assess the relative connections of the eajs and enso to the anomalies of atmospheric circulation surface temperature and precipitation in the asian pacific american region it is found that the eajs is coupled to a teleconnection pattern spanning the entire asian pacific american region with the strongest signals over east asia and the western pacific this pattern differs significantly from that associated with enso which influences the earth s climate extensively with a strongest impact on the climate over the central pacific and east a strong eajs is associated with an intensification of the weather and climate systems in asia and over the pacific such as deepening of the east asian trough and the aleutian low and strengthening of the east asian winter monsoon it is linked to colder and drier conditions in east asia and stronger convection over the tropical asia australia sector compared with enso the eajs seems to link to the climate signals of asia and the pacific more strongly an intensified eajs is also associated with anomalies of temperature and precipitation in north america due to the related changes in stationary wave patterns while the eajs does not strongly link to the tropical central eastern pacific sst it is significantly associated with the extratropical north pacific sst more specifically the second most dominant mode of the empirical orthogonal function analysis of the sst in addition a strong weak eajs seems to follow a large small meridional gradient of the western pacific sst associated with warming cooling in the tropics subtropics and cooling warming in the extratropics

the effect of north pacific sea surface temperature anomalies on the january climate of a general circulation model abstract four perpetual january integrations of an atmospheric general circulation model have been performed in each of which a different sea surface temperature sst anomaly was specified in the north pacific the observed sst anomaly for the 1976 77 winter was chosen as the basic anomaly and 1200 day runs were carded out in which this anomaly was multiplied by 1 and 2 a fifth run was performed which combined the basic midlatitude sst anomaly from 1976 77 with a tropical pacific sst anomaly representative of the mature phase of a warm el nino southern oscillation enso episode an ensemble of eight independent 90 day averaged realizations was extracted from each simulation maps of ensemble mean differences from the model climatology are presented in this paper together with estimates of the statistical significance of some of the features which appear on these maps the model response to the basic sst anomaly and to twice the basic sst anomaly is a midiatitude teleconnection pattern the pacifi

eddies and the annular modes of climate variability the dominant modes of month to month varia tion in the troposphere are realistically simulated in a gen eral circulation model whose lower boundary is prescribed with realistic topography and seasonally varying climato logical sea surface temperatures in both hemispheres these internal modes describe a nearly zonally symmetric north south shifting of the zonal jets as anomalous westerlies vac illate between high 50 60 a nd low 30 40 latitudes the eddy structures evolve with the jets and the corre sponding eddy momentum forcings support the shifts in jet position stationary synoptic wave variations mainly ac count for the total eddy forcings in the northern south ern hemisphere pronounced eddy variations occur over the north atlantic sector

evidence for the influence of the agulhas current on regional atmospheric circulation patterns abstract the agulhas current is much the strongest western boundary current in the southern hemisphere transporting about 65 sv of warm water along the southeast coast of africa south of africa it retroflects back into the south indian ocean and flows east as the agulhas return current large amounts of heat are lost to the atmosphere from the warm waters of the southern agulhas current its retroflection and the return current particularly during winter and the transition seasons it is thought that this large exchange of heat may have a significant influence on the regional atmospheric circulation the tracks and intensity of transient weather disturbances such as extratropical cyclones and on rainfall received over large parts of neighboring southern africa in an attempt to investigate the potential influence of the agulhas current on the regional atmosphere two ensembles of year long integrations of an atmospheric general circulation model are analyzed in the first ensemble the sea surface tem

frequency response properties of forced climatic sst anomaly variability in the north atlantic abstract frequency response properties of north atlantic 5 57 n sea surface temperature anomaly tsa variability with periods of several months to 20 years are characterized using the comprehensive ocean atmosphere data set coads significant direct forcing of tsa variability by the anomalous wind field primarily through the resulting anomalous surface turbulent heat flux is observed in the westerly wind and trade wind belts to characterize properties of the large scale climatic tsa response to this forcing over the entire frequency band resolved it is necessary to consider the dual role of anomalous surface heat flux as both the dominant local forcing mechanism and the dominant damping mechanism the latter through a negative linear feedback newtonian relaxation at frequencies where wind forcing is important good agreement exists between the frequency response function estimated from data and the same function theoretically predicted by a simple stochastic forcing model where the locally fo

organic facies and palynofacies nomenclature classification and applicability for petroleum source rock evaluation abstract the basic aim of the investigation presented in this paper was to determine all relevant petrographical and geochemical characteristics of organic facies and their correlation with the lithological composition sedimentation conditions and paleoenvironments application of geological and geochemical methods gives new insight into problems concerning determination of the potential and efficiency of petroleum source rocks in making the qualitative and quantitative analyses of organic matter in this study various analytical methods were used whole rock samples kerogen concentrates transmitted and reflected normal and fluorescent light the type of organic facies was used as a criterion for the identification accumulation and transformation of the organic matter paleobotanical studies of organic facies and palynofacies were used to identify types of vegetation and draw conclusions concerning the sedimentary environment various types of organic facies and palynofacies were classified in relation to the origin of the organic matter all sedimentary organic constituents of continental huminite vitrinite inertinite cuticle wood fragments tracheids spores and pollen and marine mostly autochthonous dinocysts algae foraminifera test linings acritarchs and amorphous organic matter origin have been grouped according to different classification systems a summary of these classifications is proposed with remarks on approximate corresponding coal macerals and selected kerogen types

correlation between the pacific north american pattern and the eastward propagation of sea surface temperature anomalies in the north pacific lag correlation and singular value decomposition analyses reveal that the pacific north american pattern is correlated with eastward propagating sea surface temperature sst anomalies in the north pacific the eastward movement of sst anomalies is also clear in one point lag correlation maps and longitude time plot of low pass filtered time series the timescale for the sst anomalies to travel across the north pacific is 1 year it is speculated that the propagation is related to the air sea interactions in the north pacific these findings provide observational support for the atmospheric bridge theory proposed by lau and nath 1994

long range correlations in the extratropical atmospheric circulation origins and implications abstract the atmospheric general circulation often enters into regimes that cause weather anomalies departures from an average state to persist over areas of the globe by considering 500 hpa measurements the authors demonstrate the existence of scale invariance in the variability of extratropical atmospheric circulation anomalies over the whole range of timescales resolved by the available data from a week to a decade this scale invariance indicates an absence of characteristic timescales and the presence of positive long range correlations meaning that if an anomaly of a particular sign exists in the past it will most likely continue to exist in the future moreover this scale invariance indicates that the dynamics of small scales are connected to the dynamics of large scales via a simple power law a consequence of this finding is that the memory of the system is not confined only to large scales but extends to small scales as well by investigating the hemispheric structure of 500 hpa fields ove

thermodynamic mechanisms responsible for the tropospheric response to sst anomalies in the antarctic circumpolar wave abstract tropospheric temperature and vorticity budgets for the antarctic circumpolar wave acw are diagnosed utilizing the national centers for environment prediction national center for atmospheric research reanalysis datasets from 1983 to 1992 focusing on the eastern atlantic indian and western and central pacific sectors of the southern ocean where remote forcing from the tropics has been observed to be weak there warm sea surface temperature sst anomalies are found in the acw propagating eastward together with anomalous upward latent heat flux positive precipitation low level convergence upper level divergence midlevel ascent and poleward surface wind diagnosing the anomalous temperature budget finds sst induced latent heat flux instigating anomalous mid to upper level diabatic heating and low level diabatic cooling in the absence of significant eddy heat flux divergence this diabatic heating profile is balanced by a combination of vertical and horizontal heat advection giving rise t

individual orientation measurements in quartz polycrystals advantages and limitations for texture and petrophysical property determinations individual orientation determination of quartz grains by electron channelling in principle gives the complete orientation however in routine analysis the noise level in electron channelling patterns ecps does not permit the determination of handedness of a quartz grain in a polycrystal in practice all quartz grains are arbitrarily indexed as right handed hence dauphine twins can be identified but not brazil twins this practice also means that only the centrosymmetric petrophysical properties can be determined from texture measurements these include most geologically relevant properties e g thermal conductivity thermal expansion and elasticity however other properties e g piezoelectricity which are not centrosymmetric cannot be calculated from such texture measurements some texture forming processes e g dislocation glide can also be considered to be centrosymmetric in quartz whereas others e g grain boundary migration may not be the method of quantitative texture analysis from individual measurements is briefly recalled as an example 382 grains from tongue quartzite are used to illustrate the advantages of texture analysis from ecps the orientation distribution function odf is calculated from ecps and x ray pole figures of the same sample the agreement is found to be good between the two methods proving that ecps can be used for quantitative analysis the methods used in local texture analysis and the definitions of the various misorientation distribution functions modfs are given data collected from a traverse of a quartzo feldspathic shear zone in lewisian gneiss torridon quartzite are used to illustrate local texture analysis examples from a region of shear strain of about one are given of core and mantle subgrains and dauphine twins dispersion trails of the crystallographic axes within a single grain show an apparent rotation about the intermediate structural axis y detailed analysis of the subgrain misorientation axes in specimen and crystallographic co ordinates show an important scatter implying that the subgrains resulted from local incompatibility strains rather than specimen scale kinematics the method of calculation of physical properties from individual orientation measurements is given for second and fourth order tensors using the texture data from tongue quartzite we have calculated thermal conductivity thermal expansion and seismic velocities all these properties are extremely anisotropic in quartz however it is emphasized that the presence of a second phase on grain boundaries e g water graphite may completely alter a physical property e g electric and render the values calculated from texture measurements inappropriate

impact of the december north atlantic oscillation on the following february east asian trough during winter the december north atlantic oscillation nao has an impact on the following february east asian trough eat and a significant positive correlation exists between them it is shown that the circulation anomalies affected by the december nao for december and for the following january are primarily confined to the euro atlantic sector while they extend to east asia during the following february and this is related to anomalous wave trains originating from the southwestern atlantic and spreading to the northeastern atlantic northern europe western siberia and east asia when the nao is positive phase in december the sea surface temperature sst tripole pattern is forced by persistence positive nao from december to the following january contributing to pronounced positive sst anomalies in midlatitude areas of the north atlantic during the following february the pronounced positive sst anomalies found during this period can generate feedback for atmospheric anomalies and the westerly winds are enhanced reduced to the north south side of the positive sst anomalies which result from strengthened weakened baroclinicity there in addition the rossby wave source over the northeastern atlantic shows a positive anomaly establishing a link between the positive sst anomalies in midlatitude areas of the north atlantic and the deepened eat downstream

palynological biozones and radiometric data at the carboniferous permian boundary in western gondwana absolute radiometric data obtained recently in upper paleozoic basins of south america and southern africa are available to constrain the age of some palynological biozones defined in the western gondwana some dates obtained from argentina coincide with southern africa s and are useful to constrain the palynological associations in this way the permian argentinian lueckisporites weylandites lw biozone is compared with the lueckisporites virkkiae biozone of brazil and zone 3 of south africa on the other hand the palynofloras from dwyka south africa are comparable with argentinian and brazilian associations recovered near the carboniferous permian boundary tuffaceous intervals of the dwyka group in south africa suggest the beginning of that sequence at 307 ma reaching the 290 ma at the top the available palynological paleoenvironmental and radiometric data from these three western gondwanan areas are analyzed and compared 2006 international association for gondwana research published by elsevier b v all rights reserved

reconstruction of the upper gondwana palaeoclimates based on palynostratigraphy palynofacies and sedimentology of the jurassic sequences in the tabbowa basin sri lanka abstract the palynological study of the tabbowa sediments from sri lanka reveals predominant jurassic gymnospermous pollen assemblage araucariacites australis a cooksonii a fissus and callialasporites dampieri with spore murospora florida belongs to the callovian kimmeridgian age the collective palynoflora can be correlated to the classopollis araucariacites shanbeipollenites assemblage zone of africa and the murospora florida zone of the indian subcontinent and australia showing close phytogeographic relationships from the middle to late jurassic periods palynofacies and sedimentological investigations inferred oxic dysoxic conditions that prevailed when the sediments and organic matter deposited in shallow brackish water conditions in a fluvio deltaic environment

teleconnections in the geopotential height field during the northern hemisphere winter abstract contemporaneous correlations between geopotential heights on a given pressure surface at widely separated points on earth referred to as teleconnections in this paper are studied in an attempt to identify and document recurrent spatial patterns which might be indicative of standing oscillations in the planetary waves during the northern hemisphere winter with time scales on the order of a month or longer a review of existing literature on the subject reveals the existence of at least four such patterns the north atlantic and north pacific oscillations identified by walker and bliss 1932 a zonally symmetric seesaw between sea level pressures in polar and temperature latitudes first noted by lorenz 1951 and what we will refer to as the pacific north american pattern which has been known to operational long range forecasters in this country since the 1950 s a data set consisting of nmc monthly mean sea level pressure and 500 mb height analyses for a 15 year period is used as a basis fo

the fractal shape of sutured quartz grain boundaries application as a geothermometer along grain boundaries of quartz from metamorphic and igneous rocks complex interfingering sutures may occur under the light microscope the lengths of the sutures range from approximately 10 1000 m the sutured grain boundaries are statistically self similar over one to two orders of magnitude they represent fractals their mathematical counterpart are koch curves which are developed after two to four iterations the fractal hausdorff besicovitch dimensions d of sutured quartz grain boundaries from different grades of metamorphism are between ca 1 05 and 1 30 the d value decreases with increasing temperature during formation of the sutures on a statistical basis d can be used as a measure of this temperature and therefore as a deformation related thermometer

a general circulation model study of january climate anomaly patterns associated with interannual variation of equatorial pacific sea surface temperatures abstract a general circulation model has been run in the perpetual january mode to produce several long term simulations each distinguished by a different imposed equatorial pacific sea surface temperature from each of them simulations we have extracted an eight member ensemble of 90 day averaged fields ensemble mean difference maps are presented in this paper together with an estimate of the statistical significance of features which appear in thee maps these results are compared with observational studies in the literature that present difference maps of northern hemisphere winter fields composited according to some index related to the two extremes of equatorial pacific sea surface temperature variation the results show many anomaly patterns of high statistical significance that are also in good agreement with those observed in the tropics them include 990 mb wind sea level pressure and rainfall anomalies constituting the southern oscillation as well as a 200 mb height anomaly at all longitud

charcoal recognition taphonomy and uses in palaeoenvironmental analysis abstract charcoal predominantly the product of wildfires is abundant in many sedimentary rocks deposited in a wide range of environments from terrestrial to marine it also occurs in some volcanic rocks this paper outlines aspects of charcoal formation both natural and experimental and briefly considers the taphonomic processes leading to a final assemblage this is done using examples from recent fires and through experimentation the ways in which charcoal assemblages are recognized in the field and extraction in the laboratory are also considered methods of charcoal identification are presented the range of charcoalified plant organs that can be found is discussed and a wide range of study methods outlined including light microscopy dark field light microscopy reflectance microscopy scanning electron microscopy and synchrotron radiation x ray tomographic microscopy emphasis in this paper is on the study of macro and meso charcoal above180 m finally there is a consideration of the broad use of charcoal from plant evolution studies fire history studies vegetation studies anatomical studies climate and atmospheric studies and the wider importance of charcoal for the earth and biological sciences charcoal is information rich but yet is an under utilized resource

tracking recorded fires using charcoal morphology from the sedimentary sequence of prosser lake british columbia canada abstract quantitative analyses of variations in morphological features of charcoal were undertaken in a 210pb dated sediment core from prosser lake british columbia canada seven morphological types of charcoal were defined by particle shape major minor axis ratio apparent porosity and progradation to unburned material the distribution of morphotypes and total charcoal abundances were assessed as a proxy for fire events recorded between 1919 and 2000 and to subsequent mechanisms of transportation sedimentation to lake sediments charcoal morphotypes showed distinct relationships to recorded area burned by fires fragile charcoal fragments with highly irregular porosity termed type m displayed the strongest correlation to burned area r2 0 51 p 0 0001 and did not produce any false positive signal for fires recorded within a radius of 20 km around the lake we infer that high porosity and low density type m fragments are aerially transported and directly deposited on the lake and that the fragility of type m charcoal prevents significant quantities from being secondarily transported and incorporated into the sedimentary record we propose that charcoal morphology is an important but underutilized technique that can yield important insights into fire type proximity and transportation sedimentation processes

the influence of atlantic sea surface temperature anomalies on the north atlantic oscillation abstract the influence of atlantic sea surface temperature sst anomalies on the atmospheric circulation over the north atlantic sector during winter is investigated by performing experiments with an atmospheric general circulation model these consist of a 30 yr run with observed sst anomalies for the period 1961 90 confined geographically to the atlantic ocean and of a control run with climatological ssts prescribed globally a third 30 yr integration with observed ssts confined to the south atlantic is made to confirm present findings the simulated interannual variance of 500 hpa wintertime geopotential heights over the north atlantic attains much more realistic values when observed atlantic ssts are prescribed circulation patterns that resemble the positive phase of the north atlantic oscillation nao become more pronounced in terms of the leading eof of winter means and a cluster analysis of daily fields the variance of an interannual nao index increases by fivefold over its control value atl

response of the giss general circulation model to a midlatitude sea surface temperature anomaly in the north pacific abstract the influence of a north pacific sea surface temperature sst anomaly on the wintertime atmospheric circulation is investigated with the giss general circulation model gcm 2 although no signal could be detected by the standard univariate t test a multivariate statistical analysis based on the assumption that the atmospheric response is primarily at large scales shows that the sst anomaly has an influence on the model northern hemisphere climate the signal primarily barotropic is strongest at zonal wavenumbers 3 to 5 it is above the noise level in the middle and upper troposphere but not near the ground for realistic sst magnitudes the change in geopotential height could reach several tens of meters suggesting that midlatitude sst anomalies may have a weak climatic impact however the signal is model dependent since it differs from the response of the less realistic giss model 1 to the same sst anomaly the signal is also inconsistent with 500 mb height anomalies observed during tw

orientation analysis of localized shear deformation in quartz fibres at the brittle ductile transition abstract the crystallographic preferred orientation of fibrous quartz veins deformed under subgreenschist facies conditions along a temperature gradient from 270 to 370 c has been investigated to explore the active mechanism during deformation of the quartz fibres the complete crystallographic orientation of individual recrystallized grains and subgrains was determined by using a combination of cip computer integrated polarization microscopy ebsd electron back scatter diffraction and additional specially developed image analysis techniques it was found that the quartz fibres deformed along crystallographically controlled shear bands from inverse pole figures of normals to the shear band boundaries it is evident that these bands occur along the positive and negative rhomb planes of quartz it is suggested that they are initiated as fractures along these planes inside the shear bands small grains broken off from the host grain show passive rotation of the lattice consistent with the shear sense of the shear bands continued deformation and increasing temperature lead to different recrystallization microstructures inside and outside the shear bands and to a partial obliteration of the sharp orientation relationships

principal modes of atmospheric variability in model atmospheres with and without anomalous sea surface temperature forcing in the tropical pacific abstract principal modes of low frequency atmospheric variability and the influence of sea surface temperature anomalies on such modes are investigated by examining the output from two general circulation model experiments in the first experiment the control run all boundary forcings were constrained to evolve through 15 identical annual cycles in the second experiment the sst runs the sea surface temperature conditions in the tropical pacific basin were prescribed to follow the actual month to month changes observed during the period 1962 76 which encompasses several el nino events the analysis tools employed here include empirical orthogonal functions teleconnections and composite charts two prominent modes of variability have been identified in the wintertime northern hemisphere eddy streamfunction of the sst experiment the first mode bears a strong spatial resemblance to the observed characteristic circulation pattern over the north pacific north american sector it is demonstrated th

horizontal structure of 500 mb height fluctuations with long intermediate and short time scales abstract maps of standard deviations and one point correlation maps based on twice daily data subjected to a variety of temporal filters are presented in order to document the horizontal structure of 500 mb height fluctuations with different time scales the filters have been chosen to isolate fluctuations with long time scales periods much longer than 30 days intermediate time scales 10 30 day periods and short time scales 2 5 6 day periods the one point correlation maps for long time scales resemble the teleconnection patterns described by wallace and cutzler these patterns are strongly regionally dependent with meridionally oriented dipole structures in the jet exit regions over the oceans indicative of strong fluctuations in the zonal wind for intermediate time scales the dominant patterns consist of more zonally oriented wave trains which originate in the jet entrance regions and cross the jet streams as they curve southeastward into the tropics another important distinction between th

reexamining the relationship of la nina and the east asian winter monsoon the northern and the southern modes are two distinct principle modes that dominate the winter mean surface air temperature ts variations over east asia ea the cold southern mode is represented by a significant cooling south of 45 n and is linked to la nina events an objective criterion which could distinguish the spatial distributions and the maximum center of sea surface temperature anomaly ssta is used to classify the la nina events into two categories mega la nina and equatorial la nina their impacts are inspected onto the ts southern mode the mega la nina featured by a significant k shape warming in the western pacific with the maximum ssta cooling centered in the tropical central pacific as a response an anomalous barotropic high is generated over north pacific np implying a weak zonal gradient between ocean and the ea continent which induces a neutral ts southern mode the equatorial la nina characterizes a significant cooling in the tropical eastern pacific with convective descending motions shifting eastward to the east of the dateline the resultant low level circulation anomalies show an anomalous subtropical np low and a gigantic abnormal ea continent high the strong zonal gradient results in significant northerly anomalies over ea from 55 n to southeastern china over the mid upper troposphere the anomalous subtropical np low extends westward to the korean peninsula leading to a strengthened and southward shifted ea trough such abnormal circulation patterns favor the intrusion of cold air to southern ea and correspond to a strong ts southern mode the numerical results well validate the above processes and physical mechanisms

variability of the observed midlatitude storm tracks in relation to low frequency changes in the circulation pattern abstract the principal modes of month to month variability of the wintertime storm tracks over the north pacific and north atlantic are identified by empirical orthogonal function analysis of the root mean square statistics of bandpass 2 5 6 day filtered geopotential height data for 19 yr one of the two leading modes depicts fluctuations in the level of synoptic scale activity without any noticeable spatial displacement of the storm track axes whereas the other mode is associated with meridional shifts of the storm tracks from their time averaged positions higher order modes are indicative of diversion or truncation of cyclone tracks in particular geographical regions it is demonstrated that the leading storm track modes are linked to some of the best known monthly averaged teleconnection patterns the dipolar western pacific and western atlantic patterns for the monthly mean flow are seen to be accompanied by marked changes in the intensity of the storm tracks over the western oceans whereas the m

crystallographic orientations of high angle grain boundaries in dynamically recrystallized quartz first results abstract the crystallography and geometry of high angle grain boundaries from dynamically recrystallized quartz have been studied on the basis of combined electron backscatter diffraction and universal stage measurements the complete crystallographic orientation of the grain boundaries could be calculated the u stage rotation of the grain boundaries to a vertical position reveals that they are never curved but always consist of straight segments our results show that these segments preferentially occupy rhombohedral trapezohedral and bipyramidal orientations i e orientations in a 25 50 girdle to the c axis a specific albeit low number of segments with special crystallographic orientation with respect to a neighbouring quartz grain often shows another special orientation with respect to the other neighbouring grain preferred combinations of grain boundary orientations related to both neighbouring grains are i low index rhombohedral and high index trapezohedral ii low index bipyramidal and low index trapezohedral or high index rhombohedral and iii low index trapezohedral and low or high index trapezohedral in certain cases such as at triple junctions the boundaries occupy specific trapezohedral orientations with a constant angle to the c axis this argues for energy isotropy of trapezohedral planes with the same angle to the quartz c axis in general good match coincidence site lattice csl orientations are not preferentially occupied so that most of the studied grain boundaries represent general boundaries the formation of straight segments in special crystallographic orientations indicates the crystallographic control and implies an energy reduction of certain general boundaries

a major fire event recorded in the mesofossils and petrology of the late permian lower whybrow coal seam sydney basin australia abstract petrographic and mesofossil analyses of plies from the late permian lower whybrow coal new south wales australia have revealed a significant fire event in both the swamp setting and the hinterland the fire event is characterised by a change in the maceral composition the seam during this interval being dominated by inertinite especially semifusinite following the fire event the mineral matter content of the coal increases this may be the result of increased run off and erosion in the hinterland due to destruction of vegetation this major fire event is also reflected in a change in the vegetation as represented by the mesofossil content of the seam prior to the fire event the seam contains abundant bisaccate taeniate pollen sporangia and seed like bodies of possible glossopterid affinity these are lost at the ply in which the fire event is recorded though seed like bodies become important again later the fire event also corresponds to a change in the megaspore content of the coal a new species appearing perhaps as a result of hydrological change following this major fire event a mineral rich ply was deposited which contains miospore masses of spores from fern like plants possibly representing a re colonisation event by rhizomorphs after vegetation death this evidence for a major fire and its implications for the origin of inertinites leads to the conclusion that throughout this and other permian gondwana coals fire was an integral part of the temperate mid high latitude southern hemisphere swamp ecosystem

interdecadal variations in north atlantic sea surface temperature and associated atmospheric conditions abstract evidence is presented for a distinct pattern of ocean atmosphere relationship associated with interdecadal variability in the north atlantic region using a century of surface marine observations it is shown that middle and high latitude sea surface temperature sst display a long term fluctuation with negative anomalies before 1920 and during the 1970s and 1980s positive sst conditions prevailed from about 1930 to 1960 the pattern of interdecadal sst variability is constructed by subtracting the average field during 15 cold years from that during a similar interval of warm years the early century warming and the more recent cooling display a similar spatial pattern in both cases the pattern is basin scale and largely of one polarity with maxima in the vicinity of iceland in the labrador sea and northeast of bermuda the corresponding differences in surface atmospheric conditions are determined by averaging and subtracting in the same manner fields of sea level pressure slp and surf

ftir spectroscopy and reflectance of modern charcoals and fungal decayed woods implications for studies of inertinite in coals the chemical and physical characteristics of laboratory produced charcoals natural charcoals fungal decayed woods and inertinite from a variety of western canadian coals have been investigated using ftir and standard petrologic techniques our studies confirm and extend earlier work in showing that almost all inertinite macerals can be attributed to wildfire in peat swamps and that variation in the petrological characteristics of inertinite are a product of temperature duration of heating and the nature of the initial plant material the relationships between reflectance and temperature as well as heating duration of charcoal formation are established as a reference for the examination of inertinite and the probable temperature of inertinite precursor fossil charcoal formation in paleo wildfire fungi do not directly contribute to the formation of charcoal and inertinite apart from the fungal bodies themselves funginite sclerotia and hyphae and perhaps by increasing the extent of shrinkage and cracking increasing surface area of the plant materials and thus susceptibility to charring evidence of fungal activity progressively decreases with increasing degree of charing in response to duration of heating or increased charing temperature the reflectance values and ftir spectral characteristics of inertinites in western canadian coal suggest that most inertinite formed by wildfires at temperatures over 400 c the great abundance of semifusinite in western canadian coal may reflect frequent but short duration wildfires in precursor peat swamps

on the predominant nonlinear response of the extratropical atmosphere to meridional shifts of the gulf stream abstractthe north atlantic atmospheric circulation response to the meridional shifts of the gulf stream gs path is examined using a large ensemble of high resolution hemispheric scale weather research and forecasting model simulations the model is forced with a broad range of wintertime sea surface temperature sst anomalies derived from a lag regression on a gs index the primary result of the model experiments supported in part by an independent analysis of a reanalysis dataset is that the large scale quasi steady north atlantic circulation response is remarkably nonlinear about the sign and amplitude of the sst anomaly chosen over a wide range of gs shift scenarios the nonlinear response prevails over the weak linear response and resembles the negative north atlantic oscillation nao the leading intrinsic mode of variability in the model and the observations further analysis of the associated dynamics reveals that the nonlinear responses are accompanied by the shift of the north atlantic eddy

a rotated eigenanalysis of the correlation between 700 mb heights and sea surface temperatures in the pacific and atlantic abstract associations between pacific and atlantic sea surface temperature sst and the 700 mb circulation were studied using 30 years 1949 78 of gridded monthly data the monthly data were grouped into four nonstandard seasons for the analysis the linear correlation between the two fields sst and 700 mb heights was analyzed by finding the eigenvalue solution of the mean product matrix of the cross correlations this technique introduced by prohaska was modified through the use of a varimax rotation the result is a set of pairs of patterns one pattern for each medium which explains part of the linear correlation between the two fields the number of significant modes pairs was determined by a monte carlo simulation one well known atmospheric teleconnections pattern referred to as the pacific north american pna pattern by wallace and gutzler was found in all seasons however seasonal differences were noted during the warm season the pna pattern manifests itself as the great plains g

a southern hemisphere wave response to enso with implications for southern africa precipitation ensemble gcm simulations with an imposed idealized warming of the eastern pacific ocean reveal two wave anomalies in the southern hemisphere one in the eastern and one in the western hemisphere both are statistically significant at the 99 confidence level application of a steady state linear model and a rossby wave source analysis is used to diagnose the causes of the waves the western hemisphere wave is forced by the advection and stretching of planetary vorticity by the divergent flow from the southern hemisphere component of the central pacific twin anticyclones that straddle the equator during warm events the eastern hemisphere wave is a result of the northeastward shift of the south indian convergence zone sicz that in turn is forced from the upper troposphere by convergence to the north an upper level convergence maximum over the equatorial indian ocean induces divergence to the south encouraging vertical motion and precipitation to the northeast of the sicz s normal position the resulting anomalous upper level convergence in the climatological position of the sicz as well as the anomalous vorticity flux convergence by the transients associated with an equatorward shift of the storm track behind the sicz force the eastern hemisphere rossby wave since a shift of the sicz is a fairly robust observed consequence of enso events these results suggest the mechanism by which drought conditions develop over southern africa at the height of many warm events seasonal prediction capabilities in this region can be improved by monitoring and understanding the details and consequences of the adjustment of the walker circulation near the equator outside of the pacific ocean basin

grain boundary hierarchy development in a quartz mylonite abstract orientation contrast imaging using forescatter detectors and backscattered electron diffraction techniques in the scanning electron microscope have been used to investigate the boundary hierarchy characteristics of a quartz mylonite shear zone from torridon nw scotland the boundary hierarchy is defined as the relationship between the boundary misorientations their enclosed domain size and their frequency distribution by measuring the misorientation across every grain and subgrain boundary the characteristics of the boundary hierarchy can be found two microstructural domains were studied one partially recrystallized low strain domain with large relict grains and one fully recrystallized high strain mylonitic domain our results indicate that the processes of recovery subgrain rotation and grain boundary migration recrystallization each produce identifiable boundary hierarchy signatures in the relict quartz grains we have identified the processes of recovery and subgrain rotation in the recrystallized quartz a cyclic steady state exists between these and other processes coupling these data with traditional microstructural observations allows a more rigorous investigation into the development of a high strain fine grained mylonite from a coarse grained undeformed protolith we suggest that this type of detailed crystallographic microstructural analysis can greatly further our understanding of microstructural development in shear zones and may have implications for the effective use of sub grain size palaeopiezometers

decadal and multidecadal north atlantic sst anomalies driven by standing and propagating basin scale atmospheric anomalies north atlantic winter surface atmospheric circulation anomalies that vary over decadal and longer periods are characterized by examining the life history of individual anomaly features present from 1950 to 1992 individual features observed on surface pressure anomaly pa maps propagated to the east northeast during the early to mid 1950s and to the south from 1964 to 1984 standing pa fluctuations were observed at other times the nonstationary statistical properties of this atmospheric variability were not apparent in earlier studies because the statistical analysis techniques used assumed stationarity or assumed the atmosphere was dominated by standing patterns of variability observed winter sea surface temperature anomaly ssta patterns that vary over decadal and longer periods were driven in part by these surface atmospheric anomalies through the associated anomalous surface turbulent heat flux patterns the ocean tends to be anomalously cold warm where the surface wind speed is anomalously large small local atmospheric forcing of winter ssta remains important out to longer periods than previously realized although ssta appears to respond passively to this atmospheric forcing a complete understanding of the ocean atmosphere variability documented here will require an understanding of processes responsible for driving the atmospheric circulation anomalies

palynology palynofacies and taphonomical studies of kamthi formation godavari graben southern india implications to biostratigraphy palaeoecology and depositional environment abstract the ambiguity regarding the age and palaeoecology of the kamthi formation is persisting for several years in order to find the scientific answers to this problem an integrated approach has been adopted on the samples collected from a 604 m thick sedimentary sequence borehole of the kamthi formation late permian godavari graben the compilation of detailed investigation includes the palynology palynofacies and taphonomic studies in order to establish the age reconstructing the palaeoecology and inferring the environment of deposition the palynological investigation indicates the presence of two informal palynoassemblages the lower palynoassemblage a faunipollenites striasulcites corresponds to the coarse grained sandstone dominated basal part and the palynoassemblage b densipollenites striate bisaccates occur in the upper fine grained sandstone and shale dominated sequence a detailed gondwanan correlation of the palynoassemblages assign a late permian age to the palynoflora palynoassemblage a belongs to the guadalupian age while palynoassemblage b corresponds to the lopingian age the dominance of glossopterids peltasperms conifers and cordaites derived pollens indicate the presence of thick arborescent palaeovegetation the rich cryptogam spore assemblage algal fillicopsid and equisetopsid constitute the opportunistic and rare component of the understorey flora the present study suggests that the lycopsids along with few acritarchs make their appearance post guadalupian the taphonomic studies infer that the palynoassemblages are greatly influenced by the structure of spores and pollen saccus further the palynofacies analysis reveals a cyclic change in the environment fluctuating from unstable oxic to the stable anoxic environment the occurrence of microscopic charcoal from the late permian also suggests palaeo wildfire events in the hinterland

the anomalous structures of atmospheric and oceanic variables associated with the frequency of north pacific winter blocking 1 from empirical orthogonal function eof analysis of the atmospheric and oceanic variables over the north pacific during the northern hemispheric winter 1960 2009 we were able to determine that the second mode of the eof is related to north pacific winter blocking our composite analysis reveals that the structures of the variables during winters with contrasting frequencies of blocking events are systematically different and show quite opposite pattern in the north pacific during winters with frequent blocking occurrence a north south dipole pattern of geopotential height anomaly is formed and the associated westerly winds are weakened strengthen north south of 35 n these factors bring variations of ocean advection and ocean surface heat flux resulting in a dipole pattern of sea surface temperature sst with a warm anomaly north of 35 n and a cold anomaly to the south the effect of sst on blocking is examined using an atmospheric general circulation model agcm experiment in the experiment the sst anomaly related to blocking is applied as a boundary forcing of the agcm to investigate the effect of sst on the formation of blocking from the experiment we also concluded that the winter blocking is not induced by north pacific sst forcing although consistent linkage between oceanic and atmospheric variables is evident

a response climatology of idealized midlatitude thermal forcing experiments with and without a storm track several gcm studies indicate that eddy activity may have a considerable influence on the atmospheric response to midlatitude sea surface temperature anomalies the effect of eddy activity on the atmospheric equilibrium response to idealized midlatitude thermal forcing is analyzed for an atmosphere with or without an idealized storm track experiments using a simplified global circulation model forced by thermal anomalies of different sign and location are discussed consistent with the linear theory the geopotential height field displays a baroclinic response with a shallow low high somewhat downstream of the warm cold anomaly farther downstream an equivalent barotropic response occurs with positive negative amplitude increasing with height eddy feedbacks have weak impact on the baroclinic part but the equivalent barotropic response is strongly enhanced if the bandpass filtered streamfunction tendency is in phase with the linear geopotential height response this is the case in an experiment with a warm anomaly near 408n located southwesterly of the idealized storm track in the corresponding experiment with a cold anomaly the two patterns are out of phase and the equivalent barotropic response is slightly reduced it is weakened strengthened if a warm cold anomaly is shifted about 108 poleward or equatorward relative to the idealized storm track midlatitude heat sources generate wave trains that extend equatorward and poleward developing large scale correlations between the flow at remote locations teleconnections the space time variability can be changed considerably by eddy feedbacks developing stronger variance for large scale retrogressive traveling and standing waves partially blocking like events develop

fractal analysis of experimentally dynamically recrystallized quartz grains and its possible application as a strain rate meter abstract fractal analysis of experimentally recrystallized quartz grain shapes has been employed to study the relationship between the microstructures of dynamically recrystallized quartz grains and the deformation conditions such as temperature and strain rate samples used are quartz aggregates deformed under high temperature 800 c 900 c and 1000 c and high confining pressure 400 mpa the fractal dimension is useful to quantify the shapes of the recrystallized quartz grain boundaries at each set of conditions the fractal dimension is determined as the slope of a log log plot of the length of the grain boundaries perimeters against the grain size calculated as diameters of circles having the same areas as the actual grains the results show that the shapes of grains are self similar and the fractal dimensions d change systematically being dependent on both temperature and strain rate the skew of the grain boundary defined as d 1 and showing the degree of the serration may be proportional to the logarithm of the zener hollomon parameter that includes a component of the arrhenius term this relation indicates that strain rate can be calculated from the fractal dimension and the temperature it may therefore provide a new paleo strain rate meter for plastically deformed natural rocks

paleobotanical and paleoecological constraints on models of peat formation in the late carboniferous of euramerica abstract the dominant plants of the late carboniferous lowland tropics were taxonomically and structurally distinct from those of any later time periods dominance was distributed among lycopsids ferns sphenopsids pteridosperms and cordaites and each of these groups had distinctive and different ecological preferences and amplitudes peat forming habitats were dominated by lycopsids throughout the westphalian with a significant cordaitean element in the middle westphalian during the stephanian tree ferns were dominant following major extinctions near the westphalian stephanian transition each of the major plant groups had distinctive architectures and tissue composition trees contributed up to 95 of the peat biomass and tree forms of lycopsids psaronius and medullosa lack good modern analogues the cordaites were the only woody plant group to contribute significantly to peat and then only during the mid westphalian structurally wood like lycopsid bark is the major woody tissue encountered in most westphalian coals tree ferns and pteridosperms were largely parenchymatous in construction the stigmarian root systems of lycopsids also were largely parenchymatous the tissue structure of these dominant plant suggests the need for extreme caution in the inference of mire ecological conditions or vegetational structure from coal petrographic data peat formed under arborescent ferns or pteridosperms or peat repeatedly exposed to decay and rerooting by stigmarian root systems of lycopsids would have a distinctly non woody signature and yet would have formed in a forested environment a summary is presented of the autecology and synecology of mire plants emphazing the structural framework provided by lycopsids during the westphalian certain constraints in the links between peat biomass and miospore palynology are discussed in terms of over representation under representation and non representation the formulation of smith s four phase hydroseral model is discussed and compared with more recent data available from plant paleoecology the current debate over an ombrotrophic vs rheotrophic origin of late carboniferous peats relies in large part on paleobotanical data almost entirely palynological in combination with petrographic analyses ecological studies of miospores and of coal ball and compression macrofossils and the linkage of miospores to source plants permit the re evaluation of mire successional models evidence for tree lycopsids sphenopsids pteridosperms and cordaites suggests growth mainly in rheotrophic mires tree ferns are likely candidates for growth in domed mires although evidence is ambiguous and some tree ferns clearly grew under rheotrophic conditions densospores produced by at least sporangiostrobus lycopsid subtrees have been considered diagnostic of ombrotrophic conditions abundant evidence refutes this simplistic interpretation and suggests broad ecological amplitudes for densospore producers including growth under rheotrophic conditions although plant fossils alone can not resolve most of the major debates in modern coal geology paleobotany does contribute significantly to our understanding of ancient mires an approach combining paleobotanical data with petrography sedimentology and geochemistry on a case by case basis is most likely to produce a clear picture

north atlantic thermal persistence and coherent evolution 1 north atlantic thermal persistence and coherent evolution are examined a region near cape cod and the gulf of maine is identified as the north atlantic na s most thermally persistent with a unique combination of high amplitude long lasting sea surface temperature sst anomalies a mechanism is advanced whereby that region s surface ocean reflects deep upper ocean dynamics with thermal evolution that tracks heat advection by the slowly evolving upper ocean this is consistent with the subtropical gyre playing an active and central role in na climate variability the proposed interpretation is supported by broad high lag correlations between the bermuda potential vorticity time series representing the subtropical gyre state and surface anomalies using the bermuda potential vorticity time series as a dynamical filter successive lag correlation patterns reveal surface oscillations that are not apparent in the raw surface data

a general circulation model study of the atmospheric response to extratropical sst anomalies observed in 1950 79 abstract a 30 year experiment with an atmospheric general simulation model has been performed the lower boundary condition at all oceanic grid points between 38 s and 60 n has been prescribed to follow the observed month to month variation of the sea surface temperature sst field during the 1950 79 period much of the model diagnosis presented here pertains to the midlatitude atmospheric response to recurrent sst patterns in the north pacific and north atlantic in winter the principal modes of variability of the seasonally averaged 515 mb height and sst fields have been identified using rotated principal component rpc analysis the extrema of the first atmospheric mode reside over the north atlantic and eurasia whereas the second mode is associated with height anomalies in the north pacific north american sector cross correlation analysis reveals that these two atmospheric modes am linked to leading patterns of the sst field in the north atlantic and north pacific respectively it is also demonst

the atmospheric circulation and sea surface temperature in the north atlantic area in winter their interaction and relevance for iberian precipitation abstract the ocean surface atmosphere relationships in the north atlantic area in northern winter are empirically examined by canonical correlation analysis cca this analysis is performed from two different points of view first the connection between atmospheric circulation anomalies in terms of monthly mean sea level pressure slp and monthly standard deviation of slp slp and sea surface temperature sst anomalies of the atlantic ocean are directly examined second the air sea relationships are indirectly studied through their influence upon precipitation in an area likely to be influenced by the north atlantic the iberian peninsula the canonical correlation analysis yields two pairs of patterns that describe the coherent variations of the combined sst slp fields one pair of patterns for the sst slp fields and one pair of patterns for the slp slp fields all patterns are dominant in describing variance a lag cross correlation analysis of the time coefficients indicates that monthly mea

the differences between early and midwinter atmospheric responses to sea surface temperature anomalies in the northwest atlantic abstract using an atmospheric global spectral model it is shown that the winter atmosphere in the midlatitudes is capable of reacting to prescribed sea surface temperature sst anomalies in the northwest atlantic with two very different responses the nature of the response is determined by the climatological conditions of the winter regime experiments are performed using either the perpetual november or january conditions with or without the prescribed sst anomalies warm sst anomalies in november result in a highly significant anomalous ridge downstream over the atlantic with a nearly equivalent barotropic structure in january the response is a statistically less significant trough the presence of the sst anomalies also causes a northward southward shift of the atlantic storm track in the november january cases a diagnostic analysis of the anomalous heat advection in the simulations reveals that in the january cases the surface heating is offset primarily by the strong horizontal cold advect

permian palynostratigraphy a global overview permian palynostratigraphic schemes are used primarily to correlate coal and hydrocarbon bearing rocks within basins and between basins sometimes at high levels of biostratigraphic resolution up to now their main shortcoming has been the lack of correlation with schemes outside the basins coalfields and hydrocarbon fields that they serve and chiefly a lack of correlation with the international permian scale this is partly because of phytogeographical provinciality from the guadalupian onwards making correlation between regional palynostratigraphic schemes difficult however local high resolution palynostratigraphic schemes for regions are now being linked either by assemblage level quantitative taxonomic comparison or by the use of single well characterized palynological taxa that occur across permian phytogeographical provinces such taxa include scutasporites spp vittatina spp weylandites spp lueckisporites virkkiae otynisporites eotriassicus and converrucosisporites confluens these palynological correlations are being facilitated and supplemented with radiometric magnetostratigraphic independent faunal and strontium isotopic dating

coal derived rates of atmospheric dust deposition during the permian despite widespread evidence for atmospheric dust deposition prior to the quaternary quantitative rate data remains sparse as dust influences both climate and biological productivity the absence of quantitative dust data limits the comprehensiveness of models of pre quaternary climate and biogeochemical cycles here we propose that inorganic matter contained in coal primarily records atmospheric dust deposition to test this we use the average concentration of inorganic matter in permian coal to map global patterns and deposition rates of atmospheric dust over pangea the dust accumulation rate is calculated assuming permian peat carbon accumulation rates in temperate climates were similar to holocene rates and accounting for the loss of carbon during coalification coal derived rates vary from 0 02 to 25 g m 2 year 1 values that fall within the present day global range a well constrained east west pattern of dust deposition corresponding to expected palaeoclimate gradients extends across gondwana with maximum dust deposition rates occurring close to arid regions a similar pattern is partially defined over the northern hemisphere patterns are consistent with the presence of two large global dust plumes centred on the tropics the spatial patterns of dust deposition were also compared to dust cycle simulations for the permian made with the community climate system model version 3 ccsm3 key differences between the simulations and the coal data are the lack of evidence for an antarctic dust source higher than expected dust deposition over n and s china and greater dust deposition rates over western gondwana this new coal based dust accumulation rate data expands the pre neogene quantitative record of atmospheric dust and can help to inform and validate models of global circulation and biogeochemical cycles over the past 350 myr

the relationship between sea surface temperature anomalies and atmospheric circulation in gcm experiments several 19 year integrations of the hamburg version of the ecmwf t21 general circulation model driven by the monthly mean sea surface temperature sst observed in 1970 1988 were examined to study extratropical response of the atmospheric circulation to sst anomalies in the northern hemisphere in winter in the first 19 years run sst anomalies were prescribed globally gago run and in two others sst monthly variability was limited to extratropical regions moga run and to tropics toga run respectively a canonical correlation analysis cca which select from two time dependent fields optimally correlated pairs of patterns was applied to monthly anomalies of sst in the north alantic and pacific oceans and monthly anomalies of sea level pressure and 500 hpa geopotential height in the northern hemisphere in the gago run the best correlated atmospheric pattern is global and is characterized by north south dipole structures of the same polarity in the north atlantic and the north pacific sectors in the moga and toga experiments the atmospehric response is more local than in the gago run with main centers in the north atlantic and north pacific respectively the extratropical response in the gago run is not equal to the sum of the responses in the moga and toga runs the artificial meridional sst gradients at 25 30 n probably influence the results of the moga and toga runs the atmopsheric modes found by the cca were compared with the normal modes of the barotropic vorticity equation linearized about the 500 hpa winter climate the normal modes with smallest eigenvalues are similar to the model leading variability modes and canonical patterns of 500 hpa geopotential height the corresponding eigenvectors of the adjoint operator which represent an external forcing optimal for exciting normal modes have a longitudinal structure with maxima in regions characterized by enhanced high frequency baroclinic activity over both oceans

interdecadal variability of the enso north atlantic oscillation connection in boreal summer understanding the combined effect of el nino southern oscillation enso and the north atlantic oscillation nao is of great importance for climate seasonal prediction extreme climate events in particular results in this study show that during the last hundred years 1900 to present the enso nao connection experiences a notable interdecadal change in summer june august according to a 21 year sliding correlation between them namely from no significant correlation uncoupling before the mid 1970s to a significant correlation coupling after the mid 1970s comparison analysis between the coupling epoch 1977 1997 and the uncoupling epoch 1958 1976 shows that the most pronounced circulation anomalies take place over the extratropical north pacific further analysis and numerical experiments suggest that a poleward propagating rossby wave train possibly enhanced by sea surface temperature anomalies in the extratropical north pacific associated with the developing phases of enso during the later epoch is responsible for connecting the enso signal with the nao 2012 crown in the right of canada published by johnwiley sons ltd

a review of the palynostratigraphy of gondwana sediments from the godavari graben india global comparison and correlation of the permian triassic palynoflora abstract the continental sequences of gondwana deposits from the chintalapudi sub basin of the godavari graben south india have been palynologically investigated to explore the permian triassic palynoflora total 11 distinct palynoassemblages belonging to the asselian sakmarian i ii artinskian iii iv guadalupian v vi lopingian vii viii ix induan x and olenekian xi age have been documented the palynological studies support the existence of the two coal bearing horizons in the chintalapudi sub basin one in the karharbari and barakar formations sakmarian artinskian while other in the raniganj formation guadalupian lopingian the lack of the upper barakar and barren measures roadian palynoflora indicates apparent discordance in stratigraphic sequence in this sub basin presently studied the permian triassic palynofloral transition has been found akin to the palynoflora of the salt range madagascar antarctica australia and south africa the palynofloral correlation supports the presence of guttulapollenites palaeophytogeographic province in the gondwana during the guadalupian lopingian the guttulapollenites palaeophytogeographic province co exists with the glossopteris megafloral province and extends from the salt range in the north to amery basin in the south mid zambesi luangwa basin in the west to satpura wardha godavari basin in the east

late permian palynology and depositional environment of chintalapudi sub basin pranhita godavari basin andhra pradesh india abstract the present study deals with the palynological dating correlation and depositional setting of the sediments from bore cores mgp 11 and mgp 4 from gauridevipet area of chintalapudi sub basin of godavari master basin south india on the basis of palynological studies three palynoassemblages have been identified one in bore core mgp 11 a faunipollenites protohaploxypinus and striasulcites assemblage and two in bore core mgp 4 one is characterized by the dominance of striate bisaccates and densipollenites and the other by striatopodocarpites and cresentipollenites palynoassemblages the other stratigraphically significant taxa include guttulapollenites hannonicus lunatisporites noviaulensis lunatisporites pellucidus densoisporites contactus chordasporites australiensis goubinispora spp lundbladispora microconata lundbladispora raniganjensis and klausipollenites schaubergeri the recovered taxa suggest a late permian lopingian age for these rocks this interpretation is based on the correlation of the assemblages with similar assemblages from previous gondwana studies chiefly densipollenites magnicorpus zone of damodar basin india and late permian palynoassemblages from africa antarctica australia and south america on the basis of palaeobotanical affinity of the identified microflora it has been inferred that the peat forming plant community was composed mainly of gymnosperm pollen attributable to glossopterids that includes striate and non striate bisaccates and paucity of cordaites which includes monosaccates spores are subordinate and are derived from lycopsids lundbladispora densoisporites sphenopsids latosporites and filicopsids horriditriletes lophotriletes verrucosisporites osmundacidites leiotriletes callumispora brevitriletes and microbaculispora occurring in variable proportions the dominance of subarborescent arborescent vegetation suggests a development in a forest swamp probably in a small distant marginal part of the mire or periods of standing water this flooding environment favoured the growth of herbaceous lycopsids filicopsids and sphenopsids in the palaeomire more or less similar environments of deposition have been deduced for both the sedimentary sequences on the basis of palynofacies analysis anaerobic reducing water logged peat forming conditions have been inferred based on the abundance of phytoclasts the relative abundance of structured organic matter implies the existence of a fairly dense vegetation cover in the hinterland the charcoal fragments recovered from the present study area reflects a possible wildfire in the accumulated swamps or a wildfire in the hinterland after which the sediments were flushed by fluvial systems into the swamps

wave maintained annular modes of climate variability abstract the leading modes of month to month variability in the northern and southern hemispheres are examined by comparing a 100 yr run of the geophysical fluid dynamics laboratory gcm with the ncep ncar reanalyses of observations the model simulation is a control experiment in which the ssts are fixed to the climatological annual cycle without any interannual variability the leading modes contain a strong zonally symmetric or annular component that describes an expansion and contraction of the polar vortex as the midlatitude jet shifts equatorward and poleward this fluctuation is strongest during the winter months the structure and amplitude of the simulated modes are very similar to those derived from observations indicating that these modes arise from the internal dynamics of the atmosphere dynamical diagnosis of both observations and model simulation indicates that variations in the zonally symmetric flow associated with the annular modes are forced by eddy fluxes in the free troposphere while

the equilibration of high angle grain boundaries in dynamically recrystallized quartz the effect of crystallography and temperature abstract dynamically recrystallized and sutured quartz grains from metamorphic rocks with different strain intensities and temperature conditions ranging from ca 350 c to ca 700 c have been studied universal stage measurements on quartz quartz high angle grain boundaries show that they are never curved but always consist of straight segments which preferentially occupy specific crystallographic orientations in relation to both neighboring crystals with increasing temperature the segments preferentially concentrate in a decreasing number of orientations mainly near the rhombohedral 1011 planes the crystallographic data and the observations on grain boundary geometries suggest that i grain boundary orientations are strongly crystallographically controlled ii this control is the main factor on the textural equilibration of quartz quartz grain boundaries in metamorphic rocks and iii grain boundaries from dynamically recrystallized quartz should be regarded as annealed and equilibrated fabrics that are stable against subsequent annealing as long as the material is not re deformed

fluctuations in northern hemisphere 700 mb height field associated with the southern oscillation abstract variations in the mid troposphere circulation associated with the southern oscillation so are investigated and documented using mean monthly 700 mb height data for the period 1951 79 the so was defined by a southern oscillation index soi consisting of the difference in normalized mean monthly sea level pressures at tahiti and darwin results for all four seasons are presented in the form of lagged as well as contemporaneous correlations and composites of height anomalies obtained separately for high and low soi values different so teleconnection patterns are observed for each season strongest so signals appear in the winter with soi leading the height field by one to two seasons the time lead may he useful in prognostic applications the correlation in the summer is negligible the winter teleconnection pattern over the north pacific north america north atlantic sector is similar to that shown by bjerknes and others patterns for other seasons are also presented the statistical signifi

arctic sea ice reemergence the role of large scale oceanic and atmospheric variability abstractarctic sea ice reemergence is a phenomenon in which spring sea ice anomalies are positively correlated with fall anomalies despite a loss of correlation over the intervening summer months this work employs a novel data analysis algorithm for high dimensional multivariate datasets coupled nonlinear laplacian spectral analysis nlsa to investigate the regional and temporal aspects of this reemergence phenomenon coupled nlsa modes of variability of sea ice concentration sic sea surface temperature sst and sea level pressure slp are studied in the arctic sector of a comprehensive climate model and in observations it is found that low dimensional families of nlsa modes are able to efficiently reproduce the prominent lagged correlation features of the raw sea ice data in both the model and observations these families provide an sst sea ice reemergence mechanism in which melt season spring sea ice anomalies are imprinted as sst anomalies and stored over the summer months allowing for

on the mechanism of north atlantic decadal variability abstract north atlantic decadal climate variability is studied with a coupled atmosphere ocean sea ice model ecbilt after having reached an approximate statistical equilibrium in coupled mode without applying flux corrections a subsequent 1000 yr integration is performed and analyzed compared to the current climate the surface temperatures are 2 c warmer in the tropics to almost 8 c warmer in the polar regions the covariability between the atmosphere and ocean is explored by performing a singular value decomposition svd of boreal winter sst anomalies and 800 hpa geopotential height anomalies the first svd pair shows a red variance spectrum in sst and a white spectrum in 800 hpa height the second mode shows a peak in both spectra at a timescale of about 16 18 yr the geopotential height pattern is the model s equivalent of the north atlantic oscillation nao pattern the sst anomaly pattern is a north south oriented dipole additional experiments have revealed that the decadal oscillation in ec

spatial patterns of atmosphere ocean interaction in the northern winter abstract the variability of monthly mean sea surface temperature sst anomalies over the extratropical north atlantic and pacific and its relation to atmospheric circulation anomalies over the northern hemisphere during wintertime is investigated by applying eigenvector analysis to a 39 year dataset and correlating the time series of the resulting expansion coefficients with the hemispheric 500 mb height and sea level pressure fields in agreement with previous studies the simultaneous correlation between the tone series of the expansion coefficient of the first empirical orthogonal function eof 1 of north pacific sea surface temperature sst and the hemispheric 500 mb height field resembles the pacific north american pattern and the corresponding pattern for atlantic sst resembles the north atlantic oscillation in the vicinity of the conters of action of thew patterns the sst fluctuations associated with these modes explain on the order of half the variance of 500 mb height and slightly less of

transient eddy forcing of the time mean flow as identified by geopotential tendencies abstract the forcing of the time mean flow by transient eddies is examined within the framework of a quasi geostrophic equation relating the geopotential tendency to the convergence of transient eddy transports of heat and vorticity the forcing functions of this equation are computed using observed circulation statistics for the wintertime northern hemisphere and solutions are sought for the three dimensional structure of geopotential and temperature tendencies associated with eddies of different time scales in general the geopotential tendencies associated with vorticity fluxes are of the same sign within a given atmospheric column whereas the polarity of the geopotential tendencies associated with heat fluxes in the lower troposphere is opposite to that in the upper troposphere the geostrophic wind tendencies associated with synoptic scale eddies with periods between 2 5 and 6 days are strongest in the vicinity of the oceanic storm tracks the enhanced poleward heat transports by active disturbanc

impact of localized tropical and extratropical sst anomalies in ensembles of seasonal gcm integrations a series of 120 day ensemble integrations of a general circulation model designed to assess the impact of geographically localized sea surface temperature sst anomalies in both the tropics and extratropics are described these experiments contribute firstly to an appraisal of the relative roles of tropical and extratropical sst anomalies on interannual variability of the large scale circulation in the northern extratropics and secondly to an assessment of the role of quasi stationary diabatic heating anomalies on model systematic error including blocking activity overall it is found that sst anomalies associated with el nino and la nina have a larger and more reproducible impact on the extratropics than the chosen extratropical sst anomalies these extratropical anomalies were localized to the north west pacific and north west atlantic with realistic amplitude however unlike earlier studies a response to the extratropical north pacific sst anomalies has been obtained over the north pacific which is correlated with the sign of the imposed sst anomaly the response to extratropical sst anomalies in the north west atlantic are similar to the results obtained from an earlier study the downstream responses to the extratropical pacific and atlantic sst anomalies are qualitatively similar to one another overall it is concluded that the northern large scale flow is influenced by such extratropical sst anomalies the response to idealized tropical sst anomalies was also studied in particular a localized anomaly over indonesia had a very substantial impact on the hadley circulation on zonal flow and on blocking frequency over the north pacific and europe this response was such as to reduce model systematic error locally in the vicinity of the sst anomaly remotely around the tropics and remotely in the extratropics a similar though weaker impact on euro atlantic blocking was obtained with an idealized caribbean sst anomaly further statistical and dynamical analyses suggested that the extratropical response to the indonesian sst anomaly occurs through the creation of two distinct planetary scale regimes in one of which the formation of blocks is much favoured by increased ridges on the north eastern side of the oceans

a comparison of intermonthly and interannual teleconnections in the 700 mb geopotential height field during the northern hemisphere winter abstract intermonthly and interannual teleconnection patterns in the 700 mb geopotential height field during the northern hemisphere winter are computed by the method of digital filtering and spatial correlation analysis a comparison of the teleconnection patterns of the intermonthly signal with the patterns described by wallace and gutzler shows that the western pacific western atlantic and pacific north american patterns are clearly defined by the intermonthly signal weak evidence for the eastern atlantic pattern is also found a northern asian pattern having one center over mongolia and another over the kara sea near 70 n 70 e is also found to be a prominent feature of the intermonthly signal the one point correlation maps show that the spatial correlation function is dominated by the intermonthly band the pacific north american pattern is well defined in both the intermonthly and interannual bands three additional patterns the north pacific the eurasian and the zonally symmetric seesaw appea

the geology petrology palynology and geochemistry of permian coal basins in tanzania 2 songwe kiwira coalfield abstract this study provides coal quality petrological palynological and geochemical rock eval data on permian coal seams and associated shales and mudstones of the karoo supergroup of the songwe kiwira coalfield tanzania the coal seams which have a cumulative thickness of 6 80 m occur in the shale coal sandstone facies of the mchuchuma formation of artinskian to kungurian age coal quality data calorific values volatile matter contents and vitrinite reflectances indicate high volatile c bituminous to high volatile a bituminous coals having relatively high ash yields 22 49 wt and highly variable sulphur contents 0 17 9 2 wt they could be used to fuel small scale power generation units thereby providing electricity to nearby towns and villages also the coals could be used as a substitute for wood which is becoming increasingly scarce in rural tanzania charcoal is still the main energy source for cooking and wood is used extensively in brick kilns and for making roofing tiles petrological analysis indicated that the coals are dominated by dull to banded dull lithotypes with seams at the base of the mchuchuma formation enriched in inertinite macerals up to 83 vol whereas up section vitrinite contents increase palynological analyses indicated that the assemblage in the lower mchuchuma formation scheuringipollenites assemblage is dominated by trilete spores whereas in the remainder of the section non taeniate disaccates dominate scheuringipollenites protohaploxypinus assemblage facies critical macerals suggest for most seams a marsh wet forest swamp depositional setting which is consistent with the palynological data rock eval analyses indicate type ii iii kerogen with tmax c values ranging from 426 to 440 corresponding to the early stage of hydrocarbon generation thermal alteration indices 2 to 2 and vitrinite reflectance levels 0 60 0 83 ro support the rock eval maturity assessment and despite the predominance of terrestrial derived organic matter there is evidence of oil generation and expulsion in the form of cavity and fracture filling exsudatinite

summertime evolution of decadal sea surface temperature anomalies in the midlatitude north pacific abstract to clarify the summertime evolution of decadal sea surface temperature sst anomalies and related physical processes in the midlatitudes of the north pacific numerical solutions of a three dimensional bulk mixed layer model are analyzed focusing on the contribution of the net shortwave radiative forcing at the sea surface a quantitative heat budget analysis for the ocean mixed layer relating to late 1980s decadal sst change reveals that the decadal sst anomalies decay from late spring to early summer over the entire midlatitudes of the north pacific this quasi seasonal decay of the decadal sst anomalies is controlled by an anomalous local thermal damping i e anomalous surface heat fluxes from midsummer to early autumn the anomalous net shortwave radiation flux associated with a meridional shift of the storm track acts to induce strong seasonal damping of the decadal sst anomaly in the northern kuroshio oyashio extension region in contrast in the north of the subtropical frontal region

the nature and influence of fire in carboniferous ecosystems fusain occurs widely in carboniferous coals and sediments it is now recognised to represent charcoal and be the product of wildfire the occurrence of fire is partly constrained by atmospheric oxygen levels availability and nature of fuel and by aspects of climate rainfall and seasonability in particular the majority of fires in the carboniferous were probably started by lightning strikes or by volcanic activity experiments on the charring of modern plants has shown that the reflectance of charcoal and hence fusain is directly related to temperature of formation different fire types may yield fusain assemblages of differing reflectance spectrums but it may be significant that many modern charcoal assemblages yield only semifusinites as seen by reflectance microscopy the significance of these findings is assessed in relation to the use of fusinites and semifusinites as depositional indicators as interpreted from coal petrology fires may have a dramatic effect on ecosystems not only causing changes in vegetational succession but also severe erosion can occur following a major fire which can be traced in depositional systems in this paper we document three major carboniferous sedimentary systems affected by fire clastic sedimentary systems using extensive fusain deposits in mid lower carboniferous near shore sediments in donegal ireland volcanic systems using late early carboniferous volcaniclastic sequences in the midland valley of scotland and coal and coal bearing sequences in the upper carboniferous westphalian b of the pennine basin england in the later settings the influence of fire in peat formation and succession is assessed in addition data on the vegetational composition of charcoal assemblages is considered it is concluded that fire plays a major role in many carboniferous ecosystems

horizontal structure and energetics of northern hemisphere wintertime teleconnection patterns abstract the horizontal structure and dynamical properties of the teleconnection patterns in the interannual variability of the northern hemisphere wintertime 500 mb height field are investigated regression maps based on indices for the eastern atlantic ea pacific north american pna western atlantic wa western pacific wp and eurasian eu patterns defined by wallace and gutzler are used to define the geographically fixed patterns space spectrum analysis including a spherical harmonic decomposition is applied to these maps anomalous geostrophic wind fields derived from these regression maps are used to estimate the kinetic energy conversion between the climatological mean state and the wave structures associated with the teleconnection patterns the teleconnection patterns comprise seesaw and or wavelike structures in general the kinetic energy of the teleconnection patterns is concentrated in total wavenumber n 5 and 6 components with zonal wavenumbers m 0 1 and 2 which correspond

midlatitude atmosphere ocean interaction during el nino part ii the northern hemisphere atmosphere abstract the influence of midlatitude air sea interaction on the atmospheric anomalies associated with el nino is investigated by coupling the community climate model to a mixed layer ocean model in the north pacific prescribed el nino conditions warm sea surface temperatures sst in the tropical pacific cause a southward displacement and strengthening of the aleutian low this results in enhanced reduced advection of cold asian air over the west central northwest pacific and northward advetion of warm air over the eastern pacific allowing air sea feedback in the north pacific slightly modified the el nino induced neu surface wind air temperature and precipitation anomalies the anomalous cyclonic circulation over the north pacific is more concentric and shifted slightly to the east in the coupled simulations air sea feedback also damped the air temperature anomalies over most of the north pacific and reduced the precipitation rate above the cold sst anomaly that develops in the central pacifi

charcoal fragments in surface samples following a fire and the implications for interpretation of subfossil charcoal data abstract following an uncontrolled fire in an area of heathland in sw england surface samples were taken from selected positions charcoal concentrations charcoal pollen ratio and size class frequencies were measured and the data from burned unburned and forest areas are compared charcoal concentrations show distinct variability between closely spaced samples but despite this differences are shown between the burned and unburned areas selected size classes are suggested as being appropriate for distinguishing between burned and unburned areas in palaeoecological studies while in need of replication these data should provide a basis for further studies of this type

sea surface temperature anomalies planetary waves and air sea feedback in the middle latitudes the mechanisms that contribute to the generation and damping of large scale mid latitude sea surface temperature sst anomalies are discussed the sst anomalies reflect primarily the response of the upper ocean to the changes in air sea fluxes that are associated with daily weather fluctuations heat flux forcing is dominant in the lower middle latitudes while wind driven entrainment may be most effective in the high latitudes advection by anomalous ekman current is generally less important and ekman pumping is negligible the sst anomalies decay in part because of entrainment effects associated with mixed layer deepening and oceanic mixing and in part because of heat exchanges with the atmosphere the three approaches commonly used to model the evolution of sst anomalies are reviewed case studies based on monthly or seasonal anomaly maps of the large scale sst and atmospheric anomalies numerical simulations with one dimensional mixed layer models and stochastic forcing models we stress the similarities in the different approaches and discuss their main advantages and limitations the response of the atmosphere to mid latitude sst anomalies is considered first we discuss the poorly known relationship between sst anomalies and diabatic heating using a crude assumption for the air sea coupling we consider a two layer quasi geostrophic channel model and discuss the stationary wave response to sst anomaly forcing and the resulting air sea feedback it is found that the back interaction of the sst anomalies onto the atmosphere causes a weak sst anomaly damping at large scales and a strong one at small scales the air sea coupling should also act as an eastward propagator for the sst anomalies the response of more realistic linear wave models to prescribed diabatic heating is then reviewed and it is suggested that realistic mid latitude sst anomalies have a weak influence on the atmospheric circulation corresponding to changes in the geopotential height of 10 30 m at most this order of magnitude is consistent with the results of general circulation model experiments and with the limited climate predictability associated with mid latitude sst anomalies

particle motion and the theory of charcoal analysis source area transport deposition and sampling principles from particle motion physics were applied to recurring problems of the interpretation of stratigraphic charcoal data 1 fires within catchments of lakes often produce no record in fossil charcoal curves and 2 periods characterized by no local fire e g 20th century fire suppression often display as much charcoal as times when local fire was frequent quantitative theory on source area transport deposition and sampling of charcoal shows the relationship between particle sizes counted by alternative methods of charcoal analysis pollen slides for particles 5 80 m in diameter petrographic thin sections for particles 50 10 000 m diameter and charcoal diagrams the relationship between diameter and critical and deposition velocities results in fundamental aerodynamic differences between the sizes of particles quantified by the two methods charcoal recorded on pollen slides is of a size that is difficult to lift but once entrained it remains in suspension thin section charcoal is lifted at relatively low wind velocities but it is not suspended at normal surface wind speeds thermal buoyancy during fire lofts charcoal above the forest canopy depending on particle size and wind speed pollen slide charcoal sizes are underrepresented near the fire because they remain in suspension and are preferentially exported from the burn area thin section charcoal is convected to lower heights on average and is deposited nearby following fire thin section charcoal is redistributed locally by wind and thus may enter lakes because of cohesive forces and aerodynamics more pollen slide charcoal remains on the ground and less enters lakes source areas for pollen slide charcoal are subcontinental to global and diagrams of pollen slide charcoal are biased toward nonlocal charcoal they can be used to interpret importance of fire for broad spatial and temporal scales thin section charcoal represents the catchment fire regime simulation models that generate charcoal during fire mix sediments and then sample at specified intervals indicate that 1 in the absence of sediment mixing the pollen slide method should consistently resolve individual fires that occur with an expectation of 30 50 yr 2 unless samples are continuous neither method will produce useful estimates of fire frequency and 3 even a modest amount of sediment mixing will obscure the signal

a modelling and observational study of the relationship between sea surface temperature in the north west atlantic and the atmospheric general circulation results from four pairs of 50 day wintertime integrations of the meteorological office s 5 level general circulation model with warm and cold sea surface temperature s s t anomalies of about 3 k in the northwest atlantic are described difference fields between the warm and cold integrations are statistically significant at the 1 level with positive geopotential height over the central north atlantic and weaker negative height over europe the storm track over the atlantic is displaced from its normal position results from four further pairs of integrations with halved s s t anomalies are also described the response is approximately linear with systematic differences in 500 mb geopotential height over the atlantic parts of which are just significant at the 10 level with half the full s s t anomaly overall however the model s response is weaker than could be obtained with tropical s s t anomalies of the same magnitude results from the model integrations are compared with results from an observational study of the relationship between wintertime s s t in the north west atlantic and mean sea level pressure and 500mb height two independent 30 year periods were chosen for study thus minimizing the influence of long term trends in s s t over the atlantic and europe the model results compared well with the observations with s s t data lagging the atmosphere by one month the observational study appears to show that the s s t anomalies are initially forced by perturbations in the atmospheric circulation with s s t data leading the atmosphere by one month results show that atmospheric and s s t anomalies are most persistent in the period october to december throughout the winter these lagged relationships are much weaker and not statistically significant diagnostics of e vector divergence from the gcm experiments are used to suggest that anomalous baroclinic wave activity over the atlantic is important as a momentum forcing for the anomalous time mean flow pattern on the other hand the role of thermal forcing provided by anomalous diabatic heating and transient eddy heat flux convergence may be important to substantiate this statement a simple linear steadystate two layer model of the response to extratropical thermal forcing is described with a suitable basic state flow and a mid tropospheric heat source given mainly by the transient eddy heat flux convergence the response is shown to be equivalent barotropic with a downstream ridge and ascent over the thermal source conversely results from an ocean mixed layer model are discussed which suggest that warm s s t anomalies could be maintained by a positive surface pressure perturbation positioned downstream of the anomaly through anomalous northward advection of warm ocean water by ekman drift currents this northward advection would balance the sensible and latent heat loss into the atmosphere over the s s t anomaly hence it is possible that some positive ocean atmosphere feedback may account for the persistence of such atmospheric and oceanic anomalies