instability at the winter stratopause a mechanism for the 4 day wave abstract studies using climatological fields in a three dimensional stability model show unstable modes near the polar winter stratopause with periods neat 4 days the calculated modes exhibit equatorward momentum and heat fluxes near the stratopause similar to characteristics of observed 4 day wave events demonstrating that both baroclinic and barotropic processes are important for this instability the baroclinic and baratropic components are considered separately by selectively removing either horizontal or vertical shear from the background flow although both situations reveal instability growth rates are very slow realistic growth rates occur only for climatological flows including both horizontal and vertical shears similar unstable fast moving waves are found near the polar stratopause for several winter months in both hemispheres

the 4 day wave in the antarctic mesosphere a zonal wave number one eastward propagating planetary wave observed in the high latitude winter stratosphere with a period near 4 days has been studied by a number of previous authors radar observations coupled with stratospheric analyses are here used to demonstrate that this wave known as the 4 day wave extends into the antarctic upper mesosphere previous workers have asserted that the wave is a manifestation of the observation of warm pools rotating in the polar vortex and that the pool seems to behave in a quasi nondispersive manner the observation of the 4 day wave in the upper mesosophere presented here appears to validate previous claims that the warm pools are being maintained by wavelike dynamics rather than simple advection

a study of the dynamics of the equatorial lower stratosphere by use of ultra long duration balloons 2 gravity waves in the late southern winter of 1998 centre national d etudes spatiales cnes the french space agency released six 10 m diameter superpressure balloons from a location near quito ecuador three balloons collapsed soon after launching but the remaining three drifted westward for a few weeks at altitudes between 19 and 20 km two of those balloons crossed the pacific ocean before falling above the maritime continent while the other completed a revolution around the earth and crossed the pacific for a second time before its final fall despite the small number and the relatively short duration of the flights the balloons provided a unique in situ data set for the lower equatorial stratosphere this part 1 of a two part paper describes this data set and analyzes outstanding features in the planetary scales part 2 focuses on gravity wave scale it is argued that balloon trajectories over the pacific are primarily determined by the westward drift during the easterly phase of the equatorial quasi biennial oscillation qbo and the meridional velocity field of a mixed rossby gravity yanai wave with an apparent period of 4 days and zonal wave number 4 this wave appears to have two episodes of amplification during the balloon flights it is also argued that the balloons show evidence of oscillations with periods between 2 and 4 days and of a kelvin wave with an apparent period close to 10 days and zonal wave number 1 in this way the balloon behavior provided a pictorial view of air parcel trajectory in the equatorial lower stratosphere it is stated that larger balloon campaigns can provide excellent in situ data sets for studies on the dynamics and composition of the middle atmosphere

eliassen palm fluxes of the 2 day wave abstract high resolution doppler imager hrdi winds and temperatures are used to diagnose a 2 day wave event detected in the southern hemisphere during january 1994 a novel aspect of this study is the focus upon the wave fluxes throughout the 65 100 km range and their relationship to the background state a wave packet composed of zonal wavenumbers 2 3 and 4 propagates westward with a phase speed near 60 m s 1 the periods associated with zonal wavenumbers 2 3 and 4 are 3 5 2 1 and 1 7 days respectively the morphology of the 2 day temperature and wind fields is consistent with that of a developing baroclinic wave the divergence of the eliassen palm flux of zonal wavenumbers 2 4 is dominated by the vertical convergence of meridional heat flux the wave driving or eliassen palm flux divergence per unit mass is predominantly westward with magnitudes on the order of 5 m s 1 day 1 a steady state quasigeostrophic model of the mean meridionai circulation is used to estimate the mean wind respon

horizontal structure of the geomagnetic 2 day variation 1 principal component analysis was applied to 30 year geomagnetic field data of six observatories in low latitudes to extract the longitudinal structure of the geomagnetic 2 day variation it was revealed that characteristics of the 2 day variation agree well with those of the quasi 2 day wave observed in the middle atmosphere it propagates westward with a zonal wave number 3 and the monthly mean amplitude of the variation is largest in january and july in addition an investigation into the latitudinal profile of the variation clarified that the amplitude of the 2 day variation is largest in the equatorial region although it extends to the middle latitudes a previous result of spherical harmonics analysis of geomagnetic field data was reanalyzed to identify the global horizontal pattern of overhead currents responsible for the geomagnetic 2 day variation the results showed that the 2 day variation is attributed to westward propagating current vortices the foci of which are located along the equator all these features can be explained by a scenario in which there exists a 2 day wave in the ionosphere whose horizontal structure and temporal variation resemble those in the middle atmosphere and the wind drives electric fields and currents in the ionosphere through dynamo action

generation of secondary waves arising from nonlinear interaction between the quasi 2 day wave and the migrating diurnal tide theory and past observations have provided evidence that atmospheric tides and other global scale waves interact nonlinearly to produce additional secondary waves throughout the space atmosphere interaction region however few studies have investigated the generation region of nonlinearly generated secondary waves and as a result the manifestation and impacts of these waves are still poorly understood this study focuses on the nonlinear interaction between the quasi 2 day wave 2dayw3 and the migrating diurnal tide dw1 two of the largest global scale waves in the atmosphere the fundamental goals of this effort are to characterize the forcing region of the secondary waves and to understand how it relates to their manifestation on a global scale first the fast fourier synoptic mapping method is applied to thermosphere ionosphere mesosphere energetics and dynamics sounding of the atmosphere using broadband emission radiometry satellite observations to provide new evidence of secondary waves these results show that secondary waves are only significant above 80 km the nonlinear forcing for each secondary wave is then computed by extracting short term primary wave information from a reanalysis model the estimated nonlinear forcing quantities are used to force a linearized tidal model in order to calculate numerical secondary wave responses model results show that the secondary waves are significant from the upper mesosphere to the middle thermosphere highlighting the implications for the atmosphere space weather coupling the study also concludes that the secondary wave response is most sensitive to the nonlinear forcing occurring in the lower and middle mesosphere and not coincident with the regions of strongest nonlinear forcing

small vertebrate taphonomy of la cueva del llano a volcanic cave on fuerteventura canary islands spain palaeoecological implications abstract cueva del llano is a volcanic tube of pleistocene age on fuerteventura island a strand of it ramal nuevo contains a complex sedimentary infill which has been divided into three sedimentary units and contains at least eight fossiliferous levels of holocene age the taphonomic analysis of small vertebrates found in the sediments revealed a scatological origin for the vertebrate assemblage and that the barn owl tyto alba is the main agent responsible for this concentration of bone remains furthermore the taphonomic analysis allows to reconstruct the changes in the palaeodiet of barn owls during the holocene of fuerteventura canary islands and infer the alterations produced in the vertebrate comunity during that time in the upper units of the sedimentary infill the appearance of the house mouse mus musculus is observed this immigration is correlated that is associated to a decrease of the lava mouse malpaisomys insularis proportions in the fossil assemblage also the study of small vertebrate accumulation in ramal nuevo shows that volcanic tubes can be referred to as very useful concentration trap for taphonomic studies

zonal wave numbers of the summertime 2 day planetary wave observed in the mesosphere by eos aura microwave limb sounder 1 recent observations and theoretical work suggest that the 2 day planetary wave in the summertime mesosphere is composed of multiple superposed zonal wave numbers here we use eos aura microwave limb sounder mls temperature data to determine the component zonal wave numbers of the 2 day wave in the mesosphere at latitudes of 70 s to 70 n from 2004 to 2009 we consider the effect of aliasing between different wave numbers and note that significant aliasing can occur and result in spurious signals particularly at high latitudes in winter the seasonal evolution of the different wave numbers is investigated and found to be very different between the northern and southern hemispheres in both hemispheres the wave is dominated by westward traveling waves of zonal wave number 3 and 4 w3 and w4 however in the southern hemisphere the wave is dominated by the w3 component but in the northern hemisphere the w3 component is smaller and the w4 component is often of similar or larger amplitude a small amplitude westward traveling zonal wave number 2 w2 wave is also evident in both hemispheres in the northern hemisphere the w2 amplitudes never exceed 3 k the w3 amplitudes can reach 3 5 k and the w4 can be the largest component reaching amplitudes of 4 k in the southern hemisphere the w2 amplitudes can reach up to 3 5 k the w3 amplitudes can be much larger reaching 12 k and the w4 amplitudes are smaller than in the northern hemisphere in 4 out of 5 years not exceeding 3 k the northern hemisphere w4 can reach large amplitudes in august when the w3 is small which means that the late summer northern hemisphere quasi 2 day wave is usually a w4 oscillation rather than the familiar w3 in contrast in the southern hemisphere the w3 is often larger than the w4 around the summer solstice and there are no episodes observed where the wave becomes dominated by the w4 for an extended period of time a high degree of interannual variability is evident particularly in the southern hemisphere where the w3 peak amplitudes vary from 12 k in january 2006 to 3 k in january 2009 the height latitude structure of the w4 suggests that this wave is a 4 0 rossby gravity wave

global observations of 2 day wave coupling to the diurnal tide in a high altitude forecast assimilation system we examine wave components in a high altitude forecast assimilation system that arise from nonlinear interaction between the diurnal tide and the westward traveling quasi 2 day wave the process yields a westward traveling sum wave with zonal wavenumber 4 and a period of 16 hours and an eastward traveling difference wave with zonal wavenumber 2 and a period of 2 days while the eastward 2 day wave has been reported in satellite temperatures the westward 16 hour wave lies outside the nyquist limits of resolution of twice daily local time satellite sampling hourly output from a high altitude forecast assimilation model is used to diagnose the nonlinear quadriad a steady state primitive equation model forced by tide 2 day wave advection is used to intepret the nonlinear wave products the westward 16 hour wave maximizes in the midlatitude winter mesosphere and behaves like an inertia gravity wave the nonlinearly generated component of the eastward 2 day wave maximizes at high latitudes in the lower thermosphere and only weakly penetrates to low latitudes the 16 hour and the eastward 2 day waves are of comparable amplitude and alias to the same apparent frequency when viewed from a satellite perspective

observed temperature two day wave and its relatives near the stratopause the two day wave is observed in the upper atmosphere research satellitemicrowave limb sounder temperature data around 40 58 km between december 1991 and september 1994 the two day wave temperature signature is most significant after each solstice when the derived easterly winds near the stratopause extend across the equator to at least 208 latitude in the winter hemisphere and the zonal mean winds near the equator are inertially unstable with observed inertial instability disturbances the observed two day wave consists of a 2 0 day period zonal wavenumber 3 and a 1 8 day period zonal wavenumber 4 component named 3 2 0 and 4 1 8 respectively the 3 2 0 component is dominant during two of the three available austral summers but its amplitude is much weaker than the 4 1 8 component during the two observed boreal summers during the austral summers correspondence between amplification of the two day wave temperature signatures regions of reversed potential vorticity gradient due to meridional curvature of the zonal mean flow and the critical lines for the 3 2 0 and 4 1 8 modes suggest barotropic instability as a source of both wave components momentum redistribution by observed inertial instability appears to barotropically destabilize the equatorward flank of the easterly jet where the wave components subsequently grow during the boreal summers the 4 1 8 component appears to be excited by instability that is associated with vertical shear and curvature of the flow seated above the observational domain the boreal 3 2 0 mode appears unrelated to the zonal flow instability within the observational domain and may reflect a normal mode like response during these periods

extraction studies of heavy metal pollutants in surficial sediments from the southern baltic sea off poland surficial sediment samples from the gulf of gdansk and the southern baltic sea were analyzed for cu zn cd pb ag cr co ni mn cs rb fe ca mg k na li sr al and p extraction techniques were used to establish the association of the elements with specific phases in the sediments elimination of grain size effects was achieved by analyzing the size fraction 60 of the total zn cd pb and na 60 of the cu cr mn sr ca and mn and 50 of the ag co ni cs rb li fe al k and p in the sediment up to 45 of the total cu was extracted from the sediments by 0 1 m naoh and appears to be associated with the humic acid fraction areal variations of element contents were observed most elements in total and hcl leachates were enriched in sediments from near the mouth of the vistula river correlation studies indicated that the trace elements are partitioned among several phases such as fe and mn oxyhydroxides and clay minerals in the sediments

evidence for a traveling two day wave in the middle atmosphere evidence is presented for the existence of a wave number 3 westward traveling 2 day oscillation in the temperature measurements made by the nimbus 5 scr and nimbus 6 pmr instruments the wave has largest amplitude in the mesosphere at low latitudes of the summer hemisphere and has a markedly asymmetrical meridional structure it is suggested that the wave may be a free wave similar to the 5 day wave identified in nimbus 5 scr data by rodgers 1976 the vertical structure shows little phase tilt and a slight indication of an increase in amplitude with height

the 2 day wave in the middle atmosphere observations and theory a recurrent global scale 2 day oscillation in the middle atmosphere is well documented in a variety of data sources meteor wind partial reflection satellite and rocketsonde the observed period is almost invariably near 2 1 days and the zonal structure has been established as a westward propagating wave number 3 mode observations also indicate that the meridional wind component maximizes near the equator and dominates the wind field at low latitudes these features suggest the disturbance s identification with the wave number 3 rossby gravity normal mode of a windless isothermal atmosphere such modes are found to exist largely independent of the mean fields the eigenperiods are only modestly altered by mean wind variations on the lowest three scale heights and the influence on the mode structure is local the vertical growth of amplitude is enhanced in regions of weak westerly wind relative to the wave and equatorward temperature gradient while the vertical growth rate is retarded and amplitudes may even decay in regions of strong westerlies or poleward temperature gradient in realistic mean fields the third rossby gravity mode has magnified responses very near 2 25 days in both equinox and solstice conditions the horizontal structure remains largely intact in the lowest levels however considerable asymmetry is introduced in the solstice upper stratosphere and mesosphere by the magnified vertical growth of amplitude in the summer hemisphere the latter results from the moderate easterlies and equatorward temperature gradient characteristic of the region as for the simple eigenstructure the meridional wind component in this region maximizes near the equator and dominates the wind field up to mid latitudes

metal forms in sediments from arctic coastal environments in kandalaksha bay white sea under separation processes abstract this study focuses on sediments from small restricted exchange environments along the karelian shore of kandalaksha bay white sea russian arctic which are known as separating basins and are characterised by contrasting oxidising conditions within the water column and the occurrence of anoxia in the basins that were studied no significant contamination by trace heavy metals pb cu zn and cr in particular was detected the comparative study of the two most bioavailable metal forms namely labile acid soluble and organically bound alkali soluble forms indicated that acetic acid and sodium pyrophosphate released 3 11 and 2 12 respectively of the total metal content from sediments the most bioavailable parts of metals are weakly bound to organic matter and to a greater extent associated with easily soluble amorphous fe oxides among the studied elements most of the bioavailable zn and cu was most likely bound to organic substances whereas bioavailable cr and mn were controlled to a greater extent by the formation of fe oxyhydroxide the elements studied could be arranged in the following decreasing order of average potential bioavailability cu zn mn fe cr pb in the separating basins the relative proportion of labile bioavailable metals is enhanced in relation to the neighbouring open coastal sea

the quasi 2 day wave observed in the polar mesosphere 1 using mf radar data obtained at tromso 69 6 n 19 2 e for 37 months between 1 november 1998 and 8 december 2001 we have examined characteristics of the quasi 2 day wave q2dw in the polar mesosphere in the height range from 70 to 91 km the activity of the q2dw is higher in winter months november february than in summer months may august over this height region the maximum values of the amplitude are 25 m s 1 in winter and 15 m s 1 in summer between 70 and 82 km the amplitude appears to maximize near winter solstice over the 3 years the average ratio of meridional to zonal amplitudes is 1 1 1 2 over the height region thus there is no significant preference towards either components the variations of the periods of maximum amplitude are also examined and periods with 45 2 and 54 9 hours occur more frequently than those with 48 0 and 51 2 hours however no clear seasonal trend of the variation of the period is found in addition the amplitude is modulated at 4 10 day rate with simultaneous observational data from the mf radar and the eiscat uhf radar colocated in tromso we have examined whether or not the q2dw was able to penetrate to the lower thermosphere for the period of 1 9 july 1999 it is found that the amplitude of the q2dw with period of 51 2 hours maximized at 95 km height with values of 25 m s 1 in both meridional and zonal components the q2dw was attenuated above 95 km but it appears to survive up to 108 km height in the meridional component between 85 and 95 km for the meridional component during this 8 day interval the q2dw and semidiurnal tide were the strongest among the periodic components

fast long lived features in the polar stratosphere abstract the space time fourier analysis technique proposed by salby for asynoptic satellite data has been applied to brightness temperatures derived from stratospheric sounding unit radiances from three months during the southern hemisphere winter a series of peaks are observed in the spectra for wavenumbers 1 through 4 which travel eastward with the same phase speed the wave 1 4 day and wave 2 1 8 day features observed have been described previously in the literature and the existence of a wave 3 1 2 day oscillation has also been reported the current analyses provide corroborating evidence for these using a different dataset and analysis technique in addition to reporting a previously undetected wave 4 0 8 day feature twice daily synoptic maps reconstructed from the transforms reveal consistent with the findings of prata that these waves are components of one or more warm pools circling the pole with a period of about 3 8 days these features exhibit sizable temperature perturbations 5

two day wave traveling westward with wave number 1 during the sudden stratospheric warming in january 2017 quasi two day wave qtdw propagating westward with wavenumber number 1 w1 in january 2017 is studied using global temperature observed by saber and wind observed by a meteor radar at fuke china 19 0on 109 8oe the amplitude of w1 significantly enhances during january 2017 when two stratospheric warming events occur the temperature perturbation of w1 reaches maximum amplitude of more than 6k at latitude 15o around 84 km and 95 km the structure of temperature w1 is symmetric with regard to the equator the temporal variation of w1 is consistent with the stationary planetary wave with wavenumber 2 spw2 but contrary to the qtdw propagating westward with wavenumber 3 w3 when spw2 is large during two sudden stratospheric warming events energy transfers from w3 to w1 two bursts of the two day wave in meridional wind observed by the meteor radar are just corresponding to the local maxima of w3 and w1 respectively we conclude that during january 2017 w1 is generated by the nonlinear interaction between spw2 and w3 spw2 which is modulated by the quasi 16 day perturbation in the stratosphere plays a key role in the energy transmission from w3 to w1 and it is responsible for the 16 day variation of w1

observations of the quasi 2 day wave from the high resolution doppler imager on uars a strong westward traveling oscillation with a period of 2 days and zonal wave number 3 is observed in the mesospheric and lower thermospheric winds from the high resolution doppler imager on the upper atmosphere research satellite the important events happen in january july and september october of which the occurrence in january is the strongest with an amplitude over 60ms 1 detailed analyses for the periods of january 1992 and january 1993 reveal a cause and effect relationship in the wave developing process at 95km the global structures of the wave amplitude and phase are also presented

observations of the 2 day wave in nmc stratospheric analyses abstract observational characteristics of the 2 day wave a westward propagating zonal wave 3 oscillation in the summer subtropical upper stratosphere and mesosphere are studied based on five years of national meteorological center nmc operational stratospheric analyses these data show episodic occurrence of the 2 day wave in the upper stratosphere in january centered near 20 s and july august centered near 20 n these episodes are strongly correlated with observed reversals of the zonal mean potential vorticity gradient near the core of the summer easterly jet consistent with previous suggestions that the 2 day wave is generated by an in situ instability of this jet on the other hand the horizontal and vertical structure of the waves is very similar to that calculated by salby for a global normal mode rossby wave the combination of normal mode structure and instability signature suggests that the 2 day wave is a near resonant mode forced by dynamical instability

an eastward propagating two day wave evidence for nonlinear planetary wave and tidal coupling in the mesosphere and lower thermosphere 1 temperature observations from the saber instrument on the timed spacecraft are used to investigate the structure and evolution of an eastward propagating zonal wavenumber 2 disturbance with a period near two days this oscillation obtains a maximum amplitude of nearly 10 k in the southern hemisphere mid latitudes during late january the timing and location of this planetary wave is coincident with the regular quasi two day wave intensification that occurs annually in late january the period wavenumber and spatial structure of the eastward propagating two day wave are consistent with a wave that results from a nonlinear interaction between the quasi two day wave and the migrating diurnal tide the existence of an eastward propagating wave with a period near two days coincident with the westward propagating two day wave will have an impact on the interpretation of ground based observations analysis of the saber temperature observations are utilized to determine the structure and evolution of both this eastward propagating two day wave and the classic westward propagating zonal wavenumber 3 quasi two day wave during january 2005

responses of quasi 2 day waves in the mlt region to the 2013 ssw revealed by a meteor radar chain we present an analysis of the responses of quasi 2 day waves qtdws to the 2013 sudden stratosphere warming ssw in the mesosphere and lower thermosphere mlt region the study is based on data collected by a meteor radar chain along the 120 e meridian in the northern hemisphere which consists of four stations at mohe 52 5 n 122 3 e beijing 40 3 n 116 2 e wuhan 30 5 n 114 6 e and sanya 18 3 n 109 6 e it is the first time that an enhancement of the qtdw in the neutral wind during the 2013 ssw is observed in the midlatitudes in the northern hemisphere during the ssw the amplification of the qtdw in the low latitudes is the most prominent and the direction of the mean zonal wind shows clear reversion from eastward to westward the consistent variations of the qtdws and the mean neutral wind at the four stations are very likely associated with the ssw

the 6 5 day wave and its seasonal variability in the middle and upper atmosphere 1 the zonal wave number 1 planetary wave of period near 6 5 days is a robust feature in the mesosphere and lower thermosphere mlt region with prominent seasonal variability as revealed by ground based and satellite observations this wave and its seasonal variability are well reproduced in a recent one model year run of the national center for atmospheric research thermosphere ionosphere mesosphere electrodynamics general circulation model time gcm with its lower boundary specified according to the national centers for environmental prediction analysis year 1993 wavelet analysis of the model output shows that in the mlt region the wave maximizes before and after the equinoxes and minimizes at solstices the wave amplitudes at the equinoxes are smaller than the peaks before and after but are still larger than the wave amplitudes at solstices however at the lower boundary near 30 km the wave peaks are predominantly between fall and the following spring by examining the episodes of maximum and minimum wave amplitude and by conducting additional control experiments using the time gcm the structure of this planetary wave and the factors determining the wave characteristics and seasonal variability are studied in detail it is found that the wave source mean wind structure instability and the critical layers of the wave can all affect the wave response in the mlt region and can have a strong seasonal dependence before and after equinox the wave follows the waveguide and propagates from the stratosphere to the summer mesosphere mesopause where it may amplify due to baroclinic barotropic instability such instability is usually absent from the equinoctial atmosphere so that there is no wave amplification at equinox at solstice the wave decays significantly when propagating away from its winter source due to the strong eastward winter stratospheric jet in the summer side the westward jet is also strong and the meridional and vertical extension of the critical layer of the wave is large enough to enclose the instability in the summer mesosphere mesopause at middle to high latitudes the wave is thus reflected away and prevented from reaching and amplifying at the unstable region the seasonal variation of the quasi two day wave which has zonal phase speed similar to the 6 5 day wave is also studied using similar diagnostics it is further shown that within certain seasonal window periods the variability in the mlt especially the summer mlt may closely track the lower atmospheric variability associated with these waves

abundance distribution and bioavailability of major and trace elements in surface sediments from the cai river estuary and nha trang bay south china sea vietnam abstract major si al fe ti mg ca na k s p minor mn and trace li v cr co ni cu zn as sr zr mo cd ag sn sb cs ba hg pb bi and u elements their chemical forms and the mineral composition organic matter toc and carbonates tic in surface sediments from the cai river estuary and nha trang bay were first determined along the salinity gradient the abundance and ratio of major and trace elements in surface sediments are discussed in relation to the mineralogy grain size depositional conditions reference background and sqg values most trace element contents are at natural levels and are derived from the composition of rocks and soils in the watershed a severe enrichment of ag is most likely derived from metal rich detrital heavy minerals such as ag sulfosalts along the salinity gradient several zones of metal enrichment occur in surface sediments because of the geochemical fractionation of the riverine material the parts of actually and potentially bioavailable forms isolated by four single chemical reagent extractions are most elevated for mn and pb up to 36 and 32 of total content respectively the possible anthropogenic input of pb in the region requires further study overall the most bioavailable parts of trace elements are associated with easily soluble amorphous fe and mn oxyhydroxides the sediments are primarily enriched with bioavailable metal forms in the riverine part of the estuary natural such as turbidities and human generated such as urban and industrial activities pressures are shown to influence the abundance and speciation of potential contaminants and therefore change their bioavailability in this estuarine system

the quasi two day wave observed in the equatorial middle atmosphere an oscillation with a period near 2 days is found in radar wind measurements made in the upper mesosphere and lower thermosphere at christmas island 2 n 157 w in the central pacific the oscillation is particularly strong in the meridional wind component and seems to be present almost continuously ir the 80 100 km height region although some intermittency is evident wave amplitudes are especially large about one month after the solstices in july august and in january february at times coincident with large 2 day wave events in the summer mesosphere at extratropical latitudes power spectral and complex demodulation techniques are used to study the amplitude and frequency variations of the oscillation as a function of height and time downward phase propagation is found consistent with upward energy propagation and with a vertical wavelength of about 70 km an unusual feature is a shift in wave period from near 50 hours in july august to 48 hours in january february when the largest amplitudes up to 45 m s 1 are observed a 16 hour oscillation is also found at times when the 2 day wave amplitudes are largest the observations are consistent with the 2 day wave being a manifestation of the 3 0 rossby gravity normal mode another weaker oscillation is also found in the meridional wind field at a period near 44 hours this oscillation may be due to the 2 0 normal mode

the southwesternmost record of sicista mammalia dipodidae in eurasia with a review of the palaeogeography and palaeoecology of the genus in europe abstract we describe the southwesternmost specimen of sicista betulina mammalia dipodidae and of the genus sicista found to date in eurasia which comes from the early late pleistocene mis 5 site of lezetxiki ii arrasate basque country spain in the north of the iberian peninsula sicista is a relatively common taxon in quaternary deposits although not numerically abundant due to ecological and taphonomical reasons in the light of the new discovery we briefly but comprehensively review the palaeogeography and palaeoecology of the genus in europe average colder and drier conditions during the pleistocene allowed sicista to get as far south as chios island in the aegean sea and as far west as lezetxiki in the iberian peninsula a cold moderately humid environment with dominant grasslands and coniferous forests inferred from the palaeobiological associations including human remains at lezetxiki ii was ideal for s betulina given its current ecological requirements

the environment in the caucasus in the upper paleolithic late pleistocene evidence from the small mammals from dzudzuana cave georgia abstract the mis 3 2 transition denekamp interstadial and beginning of the lgm is a crucial point in time for understanding adaptation of modern humans to climate the southern caucasus is a unique place to study human ecology within this time period because it served as a refugium during the last glacial maximum lgm and thus allows us to study how human populations responded to the climatic shifts during the last glacial this study presents the results of the paleoecological analysis of dzudzuana cave during the mis 3 2 transition using small mammal community structure as a proxy for paleoenvironment of the four units in dzudzuana units a through d unit c divided into subunits c5 to c1 has been dated to 27 24 ka cal bp and the mis 3 2 transition thus unit c allows for a diachronic analysis throughout this important time period small mammals were found primarily in subunit c2 and c1 analysis of the small mammal assemblages of dzudzuana subunits c2 and c1 confirm the paleoecological reconstruction obtained from macrobotanical remains and suggest a refugium habitat during the last phase of mis 3 and the onset of the lgm comparison with a contemporaneous site in the region satsurblia suggests a high spatial temporal mosaic habitat in the region small refugium areas within the rioni river valley and its tributaries that enjoyed ameliorated climatic conditions and proximity to water resources may have promoted local human habitation furthermore results suggest that the small mammal assemblages of dzudzuana are non analogue communities typical of european denekamp assemblages and provide a new datum point for the faunal remains during this time period

an observational study of high latitude stratospheric planetary waves in winter abstract nimbus 4 and 5 radiances representing temperatures in the upper and lower stratosphere are analyzed to obtain power and coherence squared spectra at high latitudes during the winters of both hemispheres the spectra for zonal wavenumbers 1 3 are presented indicating a variety of wave features which exist in the upper stratosphere an eastward moving wavenumber 1 feature with 4 day period is described in greater detail the possible nature of this wave is briefly discussed a second wave observed only in the southern hemisphere wavenumber 2 field is found to be westward moving with period near 2 3 days

a comparison study of the auroral lower thermospheric neutral winds derived by the eiscat uhf radar and the tromso medium frequency radar 1 a comparative study of the neutral wind in the polar upper mesosphere lower thermosphere is conducted using two radars the european incoherent scatter eiscat uhf radar 931 mhz and the tromso mf radar 2 8 mhz colocated in northern scandinavia comparisons of winds are made in case studies as well as on a statistical basis on the basis of simultaneous observations obtained by the two radars comparisons over a height range from 90 to 100 km are made for about 20 days between february and october 1999 in these comparisons we directly compare temporal wind variations on the other hand mean winds as well as diurnal and semidiurnal components are derived using 1 month averaged wind data obtained by the medium frequency mf radar for 1999 they are compared with those derived from 56 days of eiscat data studied by nozawa and brekke 1999a 1999b in the case studies we have also utilized altitude profiles of electron density obtained by the eiscat radar at and above 62 km height to determine the total reflection height as well as to estimate the effect of group retardation for 2 8 mhz radio wave it can be seen that the effect of particle precipitation sometimes penetrates into the d region down to 84 km generally wind velocities derived by eiscat with the monostatic method exhibit significant scatter with time below 100 km while the number of the mf radar wind data sharply decreases above 90 km except for summer these facts make the comparison difficult but no significant departures between different radar winds are identified on an instantaneous basis in the statistical studies generally both altitude profiles are well connected or continuous but significant disagreements are observed for the mean wind and the tidal components for summer on the basis of these comparisons we raise strong concerns regarding the use of summer wind data above 91 km obtained by mf radar located at high latitude under high solar activity conditions the wind values during the winter and equinox observed by the two radars are complementary thus here is a good opportunity to utilize wind data from the two different radars through a year which then enables us to cover a wide height range approximately 70 120 km this wide range gives us good opportunities to examine the mesosphere lower thermosphere coupling processes based on observational data

radar observations of longitudinal variability of tidal planetary waves and mean motions in the tropical mesosphere during the summer of 1995 two mf radars located at hawaii and puerto rico were in operation to measure mesospheric motions we use the data obtained at the two sites to study the longitudinal variability of mean winds planetary waves and tides on average the winds at puerto rico were more westward and equatorward than those at hawaii quasi 2 day planetary wave activity was evident most of the time from june 28 to july 25 the quasi 2 day wave had a zonal wave number m of 3 during one occasion and 4 during another and the periods of the two planetary waves were 56 and 48 hours respectively the diurnal tide at puerto rico was stronger than that at hawaii above 86 km and the semidiurnal tide at hawaii was strongly damped in the altitude range of 90 98 km both the semidiurnal and the diurnal tides were apparently modulated by longer period waves which was perhaps the most important factor in accounting for their large spatial and temporal variability the phase difference at the two sites deviates considerably from the expectation of purely migrating tides

global distribution and variability of quasi 2 day waves based on the nogaps alpha reanalysis model this study presents the analysis of 14 months january 2009 february 2010 of continuous hourly nogaps alpha reanalysis data used for examining the quasi 2 day wave otdw the global structure and seasonal variability of the eastward and westward traveling qtdws in all meteorological fields geopotential height zonal and meridional wind and temperature have been studied the use of hourly reanalysis data allows a comprehensive understanding of the global spatial temporal qtdw distribution by simultaneous separations of all tides and planetary waves the wave characteristics amplitudes and phases are presented in latitude range 80 and altitudes from 15 to 95 km two different types of eastward traveling waves are identified i waves at middle and high latitudes with zonal wave numbers 2 and 3 which are observed in the local winters and ii waves observed predominantly over the equator with zonal wave number 2 which do not have a well defined seasonal variability but show some enhancement between june and august while the first type waves are seen in all meteorological fields the second ones are not seen in the meridional wind and belong to the ultra fast kelvin waves two different types of westward traveling waves have been identified as well i waves at middle and high latitudes with zonal wave numbers 2 3 and 4 which are observed mainly in summer hemisphere and ii waves observed predominantly over the equator with zonal wave numbers 1 2 and 3 enhanced predominantly at both solstices but are seen in other seasons as well while the first type waves are seen in all meteorological fields the second ones are observed in the meridional wind and are rossby gravity normal modes

multi instrumental observations of the quasi 16 day variations from the lower thermosphere to the topside ionosphere in the low latitude eastern asian sector during the 2017 sudden stratospheric warming event

two day wave structure and mean flow interactions observed by radar and high resolution doppler imager data obtained with four mf and meteor radars at equatorial and subtropical sites and with the high resolution doppler imager hrdi instrument aboard the uars satellite were used to examine the structure wave mean flow interactions and potential sources of the 2 day wave in the middle atmosphere during three southern hemisphere summers the three wave events were highly transient having typical durations of 20 to 30 days and exhibiting modulation at shorter periods temporal variations were found to exhibit good correlations between radar and hrdi data radar and hrdi data were used to estimate those components of the eliassen palm flux that could be assessed with these data meridional fluxes of momentum and heat were computed using hrdi data and agree reasonably with the momentum fluxes computed from radar data at discrete locations these fluxes were found to exhibit consistent latitudinal structures each year suggesting systematic wave excitation and wave mean flow interactions meridional momentum flux gradients were seen to be anticorrelated with zonal wind accelerations in a manner consistent with wave forcing of the large scale circulation the apparent wave mean flow interactions suggest that the 2 day wave could be a transient response to baroclinic instability of the summer hemisphere mesospheric jet a calculation of the meridional gradient of quasi geostrophic potential vorticity using hrdi winds and the cospar international reference atmosphere cira 1986 temperatures exhibits a region of instability in the lower and middle mesosphere extending into subtropical latitudes and provides additional evidence of a possible source of this motion via baroclinic instability of the summer hemisphere jet structure

first observations of short period eastward propagating planetary waves from the stratosphere to the lower thermosphere 110 km in winter antarctica unique fe lidar observations in may 2014 at mcmurdo combined with aura microwave limb sounder mls measurements lead to a new discovery that the amplitudes of 4 day and 2 5 day planetary waves pws grow rapidly from 1 2 k at 100 km to over 10 k at 110 km this report is also the first observation of short period 1 5 days eastward propagating pws from 30 km all the way to 110 km the specified dynamics whole atmosphere community climate model reproduces the observed three dominant peaks of amplitudes in temperature and coherent vertical phase structures the data model comparison indicates a possible mechanism after pws originated from the stratosphere dissipate along the critical level the surviving waves are amplified by in situ instability in the mesosphere and lower thermosphere resulting in the second third peak in geopotential temperature this third peak in temperature explains the pw amplitude growth from 100 to 110 km

a numerical simulation of the two day wave near the stratopause abstract the middle atmosphere version of the national center for atmospheric research community climate model 2 maccm2 mechanistic model is used to simulate several aspects of the observed two day wave near the stratopause and its possible connection with inertial instability model experiments show that for a prescribed initial wind condition with strong horizontal wind variation in the tropics inertial instability can trigger the two day wave an increase in horizontal wind curvature fostered by inertial instability circulation barotropically destabilizes the easterly jet in low summer latitudes and allows first the growth of the wavenumber 4 and then the wavenumber 3 component of the two day wave near the stratopause the two day wave eliassen palm flux is directed equatorward away from the wave s critical line source and westerly momentum is transported into the easterly jet core by the wave while much of the wavenumber 4 energy is confined near the stratopause the wavenumber 3 energy can prop

small mammals from marine isotope stage 5 at klasies river south africa reconstructing the local palaeoenvironment abstract klasies river a significant middle stone age msa site preserves remains of anatomically modern humans and a 21 m sequence of human habitation that shows use of sophisticated lithic technology and systematic exploitation of marine and terrestrial resources in this paper micromammals recovered from the lower msa sequence msa i and msa ii at klasies river main site have been analysed to provide proxy data for palaeoenvironmental reconstruction small mammals recovered from 183 separate layers ensure a detailed record of local climate and vegetation during marine isotope stage mis 5 taphonomic analyses indicate that avian predators accumulated the micromammals analysis of post depositional processes has provided information on intra site variability and utilisation the palaeoenvironmental reconstruction shows changes in rainfall seasonality within mis 5 there was transient movement towards more aseasonal rainfall and significant alterations in the vegetation composition from mis 5e to mis 5a our study adds new insights to palaeoenvironmental conditions on the cape coast during mis 5

multiple origins of bondi cave and ortvale klde nw georgia obsidians and human mobility in transcaucasia during the middle and upper palaeolithic abstract using pixe four types of elemental compositions were found among obsidian artefacts from the bondi cave and ortvale klde middle to upper palaeolithic sites in nw georgia one of those types corresponds to obsidians from the chikiani source whose compositions were determined with a very good agreement by pixe and icp aes ms the composition of chikiani obsidians is remarkably constant despite k ar and 39ar 40ar extrusion ages from ca 2 4 and 2 8 ma the compositions of two other groups of obsidian artefacts are similar to source materials from eastern anatolia and armenia in particular ikisdere sarikamis gutansar and hatis obsidian is only a minority component in the lithic assemblages at the bondi cave and ortvale klde both neanderthal and modern human populations used obsidian in particular from chikiani considering that the shortest walking distance to this nearest source is at minimum of about 180 km and to other potential sources of more than 350 km it is suggested that this material reached these two sites mostly if not exclusively by a series of down the line exchanges

statistical testing of community patterns uppermost hamilton group middle devonian new york state usa abstract we present an extensive and rigorously controlled quantitative paleoecological study within an interval of inferred coordinated stasis this middle devonian hamilton group study completes a 20 yr project by providing data within the unresolved upper hamilton group section together with other rigorously controlled studies these data sets have the potential to address the larger question of coordinated stasis in the fossil record we collected data from the windom member moscow formation uppermost hamilton group to test different statistical approaches to define paleocommunities we evaluate various techniques including non parametric multidimensional scaling and agglomerative hierarchical clustering to decipher community patterns additionally we advocate regular use of cluster significance testing along with anosim i e analysis of similarities when examining ecological data together these techniques test the significance of sample groups more rigorously than conventional testing e g discriminant analysis or analysis of variance anova our results indicate that communities within this upper hamilton group interval exhibit variable taxonomic membership within a relatively stable ecological structure

the taphonomy and palaeoenvironmental implications of the small mammals from karain cave turkey the small mammal accumulations in the pleistocene deposits of karain cave are investigated to identify the predators and possible biases in the fossil assemblages seven small mammal assemblages are studied in chronological order from two chambers of the cave the main chamber e and the side chamber b the lowermost level within the whole sequence is proto charentien which corresponds to an early stage of the middle palaeolithic the main part of the material belongs to middle palaeolithic layers the most important aspect of the fossil record in the cave is the human occupation without any interruption through the pleistocene to holocene the small mammal fossil evidence in the cave denotes the presence of opportunistic predators throughout the sequence with one exception and these produce balanced samples of small mammal faunas in the habitat the lack of bias in the small mammal faunas allow the interpretation of local environments showing that partial steppe and arid conditions existed during deposition of the lowermost levels of the middle palaeolithic in karain cave and that these shifted into more temperate and wooded habitat in the upper levels evidence from the side chamber indicates some differences with a more open grassy environment in the mediterranean part of anatolia the temperate and moist conditions in the middle palaeolithic were superseded by more arid conditions in the upper palaeolithic followed by a decrease in steppe conditions during the epi palaeolithic period

pleistocene amphibians and squamates from the upper jordan rift valley gesher benot ya aqov and nahal mahanayeem outlet mis 20 18 and mis 4 3

the quasi 2 day wave observed in the polar mesosphere comparison of the characteristics observed at tromso and poker flat 1 a comparison of the quasi 2 day wave q2dw observed at tromso 69 6 n 19 2 e and poker flat 65 2 147 6 w is presented at four heights of 70 76 82 and 88 km using wind data taken for 4 years from 1 november 1998 to 7 november 2002 the characteristics of the q2dw such as seasonal variation occurrence of period of maximum amplitude ratio of meridional to zonal amplitudes shape of altitude profile of phase and modulation of amplitude at a 4 10 days rate found at poker flat are very similar to those found at tromso reported by nozawa et al 2003 the activity of the q2dw is higher in winter than in summer for meridional and zonal components at the two sites long term variation i e seasonal variation of the q2dw is found to be similar between the two sites while short term variations i e over several days do not synchronize well with each other the ratio of amplitudes of the q2dw between the two sites varies mainly between 0 5 and 2 and there is no significant preference toward either site phase differences of q2dws between the two sites are examined and it is found that in phase like events are more frequently seen than out of phase like events at 76 82 and 88 km in winter and at 88 km in summer this can be interpreted to mean that the zonal wave number of the q2dw appears to be 2 or 4 more often than 3 in the polar upper mesosphere these results suggest that observed q2dws have features consistent with the rossby gravity wave mode but the amplitude and phase of the q2dw are affected significantly by local sources a possibility that the observed q2dw is an eastward moving wave is also discussed