inertia gravity waves associated with deep convection observed during the summers of 2005 and 2007 in korea 1 characteristics of inertia gravity waves associated with convection are investigated in the lower stratosphere using high resolution radiosonde data observed from 18 june to 15 july of 2005 and 2007 in korea three dimensional ray tracing model and reanalysis data are used to investigate the propagation and the sources of the observed waves the observed waves associated with convections are discriminated based on the existence of convections when and where the rays reach the average height range of convective clouds waves observed in 2005 and 2007 show similar spectral characteristics but wave energy in 2007 is significantly larger than in 2005 the observed waves propagate from three source regions the northeastern southeastern and western regions around korea they show preferential propagation directions based on their sources and convections from the western region generate larger amplitude gravity waves than the other two regions the spectral characteristics of the observed waves are determined largely by those of the convective forcing along with the wave propagation condition associated with background wind and stability the significantly larger mean wave energy in 2007 occurs because more observed waves originate from the western region of korea in 2007 than in 2005 where convective forcing is much larger than in the other source regions

inertia gravity waves observed in the lower stratosphere over macquarie island abstract this study examines the properties of inertia gravity waves observed in the lower stratosphere over macquarie island how these properties vary with season and the likely source of the waves the waves are observed in high resolution upper air ozonesonde soundings of wind and temperature released from macquarie island during the 1994 ashoe maesa program the properties of the inertia gravity waves observed in the soundings are quantified using hodograph and rotary spectral analyses the analyzed waves have horizontal wavelengths between 100 and 1000 km vertical wavelengths between about 1 and 7 km intrinsic frequencies between f and 2f and horizontal trace speeds between 50 and 30 m s 1 there appears to be a seasonal cycle in the inertia gravity wave activity in the lower stratosphere the minimum being in the austral winter when the background zonal flow is strong and westerly and its vertical shear is positive in contrast the variance of the horizontal perturbation winds does not show a

the seasonal cycle of lower tropospheric gravity wave activity at davis antarctica 69 s 78 e abstracta vhf wind profiling radar located at davis in coastal east antarctica 69 s 78 e collected data from september 2009 to august 2011 in the lower troposphere gravity wave activity is quantified using the radar s wind velocity variances era interim and antarctic mesoscale prediction system amps forecast output are used to understand the gravity wave activity in the context of the synoptic scale meteorology and to identify the likely source of the observed gravity waves the seasonal cycle of lower tropospheric gravity wave activity 2 0 3 2 km altitude obtained from the radar data for waves with ground based periods of 16 min 12 8 h reveals a maximum in winter and a minimum in summer the largest gravity wave activity corresponds in time to the presence of a surface depression centered north of davis that directs strong northeasterly winds along the antarctic coastline case studies indicate that these winds interact with an ice ridgeline located around 60 km northeast and upwind of davis th

gravity wave propagation and dissipation from the stratosphere to the lower thermosphere 1 one night 28 october 2003 temperature and horizontal wind measurements by a resonance sodium na wind temperature lidar at maui 20 7 n 156 3 w and temperature measurement by a rayleigh lidar at mauna loa observatory mlo 19 5 n 155 6 w hawaii were used to study gravity wave gw propagation from the lower stratosphere to the lower thermosphere a dominant wave mode was identified from 35 to 103 km the wave was partially dissipated and propagating upward with a scale height of temperature amplitude at 14 km a damping layer was present around the stratopause where the wave amplitude was small which also corresponded to a low static stability layer the vertical wavelengths were larger in the mesosphere 12 13 km than in the stratosphere 6 7 km consistent with the decreasing static stability with altitude hodograph analysis of the na lidar wind data showed that the wave was propagating northward and the horizontal wavelength was 2140 km and intrinsic period was 15 h in the region 84 103 km the apparent period was 6 h and consistent with doppler shift of the background wind it is suggested that the convective zone over the equator to the south of hawaii provided a constant gw source that is responsible for the observed gw throughout the night

latitudinal and seasonal variations of inertial gravity wave activity in the lower atmosphere over central china 1 gravity wave activities and background dynamical structure in the troposphere and lower stratosphere tls over five stations at latitudes from 10 n to 40 n were statistically studied by using the data from radiosonde observation on a twice daily basis at 0800 and 2000 lt the background dynamical structure exhibits evident latitudinal and seasonal variations and has a profound influence on inertial gravity waves in the tls in the analyses of inertial gravity waves according to the background structures the observation height coverage is divided into two segments which are the tropospheric 0 10 km and lower stratospheric segments 18 25 km the observational results indicate that the tropospheric jet is the most important excitation source for gravity waves both in the troposphere and lower stratosphere and it plays different roles in determining the morphology of gravity waves in these two segments the jet excited gravity waves in the troposphere can propagate both upward and downward and only part of the upward propagating waves can penetrate into the stratosphere because of the doppler shifting by the jet while in the lower stratosphere gravity waves excited by the tropospheric jet propagate upward most differences between the tropospheric and lower stratospheric results can be explained from the linear dispersion relations of gravity waves and the doppler shifting by the strong tropospheric jet however such an explanation is qualitative rather than quantitative generally the observations reveal that the tropospheric gravity waves are mainly controlled by their excitation sources implying the wave characteristics may be regarded as at least an indicator of the wave excitation source characteristics these results suggest that in order to attain a more realistic source parameterization for gravity waves propagating in the middle and upper atmosphere more attention should be paid to the gravity waves in the troposphere moreover the causes of the pronounced peak of lower stratospheric gravity wave intensity at tropical latitudes revealed by previous observations are also discussed

observation of local tidal variability and instability along with dissipation of diurnal tidal harmonics in the mesopause region over fort collins colorado 41 n 105 w 1 during the 9 day continuous campaign in september 2003 the colorado state university sodium lidar observed significant short term tidal variability in both diurnal and semidiurnal tides above 85 km on days 265 268 both diurnal and semidiurnal amplitudes dramatically increased on day 267 with a continuous phase advance in diurnal tidal harmonics causing local atmosphere to become dynamically unstable following the dynamical instability associated with tides we observed an equally dramatic decrease in diurnal amplitude which was accompanied by rapid and continuous phase retardation at 87 km on day 268 the accompanying diurnal phase profiles changed from propagating mode to evanescent mode since the time scale of the observed variability during days 265 268 is less than 1 day gravity wave tidal interaction at least is partially responsible for the observed variability the observed changes in tidal wind amplitudes and phases were observed to correlate with gravity wave gw activities and the direction of gw momentum exhibited and discerned concurrently by an oh all sky imager at nearby yucca ridge station consistent with well known models of tidal gw interactions the stability analysis in the night of 267 when both diurnal and semidiurnal reached the maximum amplitudes revealed that the running daily tidal waves alone superimposed with the associated mean state could force the atmosphere into local dynamical instability near 90 95 km the eddy diffusion associated with the instability is believed to have caused a strong dissipation of diurnal tide as observed on day 268

radar observations of a 3 day kelvin wave in the equatorial mesosphere mesospheric radars are used to investigate the characteristics of a kelvin wave from two equatorial sites jakarta indonesia in the western pacific and christmas island in the central pacific our study focuses on the time span from mid january through mid october 1993 a kelvin wave with a period near 3 days was detected throughout this 9 month duration although it underwent deep amplitude modulations on a 20 day timescale a fitting procedure is applied to study the phase amplitude behavior of the wave the vertical wavenumber was measured by the radars and found to be small wandering around zero with only a weak bias toward downward phase progression the long vertical wavelength suggests that the wave was predominantly zonal wavenumber 1 the amplitude of the wave measured by the jakarta meteor scatter radar was much larger than the amplitude measured by the mf partial reflection radar at christmas island the smaller wave amplitude at christmas island could at least partially be due to a measurement bias associated with mf radars the radar at jakarta is a vhf meteor scatter radar and is not susceptible to this bias however the mean velocities and the amplitudes of the tidal and quasi 2 day wave components were in good agreement at the two sites the estimated 9 month averaged zonal acceleration was 0 67 ms 1 day 1 over jakarta at 94 98 km and only about half as large over christmas island the magnitude of the zonal acceleration occasionally showed large enhancements which suggest the importance of refractive effects associated with vertical and temporal variations in the mean winds the larger 3 day wave amplitudes and inferred acceleration at jakarta may reflect its location in the western pacific a region of high convection and hence an excitation region for equatorial waves the relative phase of the wave between the two radar sites gradually shifted over a timescale of weeks these smooth variations in relative phase are suggestive of a superposition of waves with different zonal wavenumbers perhaps radiating preferentially from one longitude the phase of the wave as a function of altitude and time was much more disordered at jakarta than at christmas island the conjecture can be made that the more chaotic phase structure observed over jakarta is due to higher order zonal wavenumber components which weaken as they propagate eastward

a model study of zonal forcing in the equatorial stratosphere by convectively induced gravity waves a two dimensional cloud resolving model is used to examine the possible role of gravity waves generated by a simulated tropical squall line in forcing the quasi biennial oscillation qbo of the zonal winds in the equatorial stratosphere a simulation with constant background stratospheric winds is compared to simulations with background winds characteristic of the westerly and easterly qbo phases respectively in all three cases a broad spectrum of both eastward and westward propagating gravity waves is excited in the constant background wind case the vertical momentum flux is nearly constant with height in the stratosphere after correction for waves leaving the model domain in the easterly and westerly shear cases however westward and eastward propagating waves respectively are strongly damped as they approach their critical levels owing to the strongly scale dependent vertical diffusion in the model the profiles of zonal forcing induced by this wave damping are similar to profiles given by critical level absorption but displaced slightly downward the magnitude of the zonal forcing is of order 5 m s21 day21 it is estimated that if 2 of the area of the tropics were occupied by storms of similar magnitude mesoscale gravity waves could provide nearly 1 4 of the zonal forcing required for the qbo

river terrace systems in north west europe an archive of environmental change uplift and early human occupation abstract staircases of large scale aggradational river terraces are a notable feature of many valleys in the temperate lattitudes particularly in areas beyond the reach of the erosive activities of pleistocene ice sheets it is now recognized that the cyclic fluctuations of climate during the quaternary have driven the generation of terraces through the direct and indirect influence of both temperature and precipitation on fluviatile activity where fossiliferous deposits are preserved within terrace sequences it is often possible to date these and to correlate them with the oceanic record thus providing an important framework for the evidence of environmental change on land middle and late pleistocene terraces in different areas can commonly be seen to have formed in synchrony with glacial interglacial cycles or with longer periodicity megacycles climatic forcing alone is insufficient to cause terraces to form however uplift is also necessary so that terrace sequences can provide a useful record of crustal movement in northwest europe where some of the best known studies of river terrace sequences have been carried out the fluviatile deposits are also an important repository for palaeolithic artefacts from which a record of early human occupation can be reconstructed

mauer the type site of homo heidelbergensis palaeoenvironment and age abstract the mandible of homo heidelbergensis was found 1907 in the sand pit grafenrain at mauer in coarse fluvial sands 24 m below the surface deposited in a former course of the neckar river these mauer sands are overlain by a series of glacial climate loess deposits with intercalated interglacial palaeosols which can be correlated with quaternary climate history thus indicating an early middle pleistocene age for h heidelbergensis the mauer sands are famous for their rather rich mammal fauna which clearly indicates interglacial climate conditions the faunal evidence in particular the micromammals place the mauer sands into mis 15 or mis 13 although most stratigraphic arguments favour correlation to mis 15 and therefore to an age of ca 600 ka

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

large potential energy of gravity waves over a smooth surface with little convection simulation and observation 1 a numerical experiment is conducted using an atmospheric general circulation model agcm to investigate the presence of the large potential energy over a region of low topography and little convective activity focusing on the tropical atlantic region 10 e to 20 w 0 to 20 s it is found that gravity waves with a time period of 24 hours are excited near the equator 5 15 n in a region of large moist heating extending vertically up to 10 13 km the gravity waves propagate upward from this region with a bias toward the south and are manifested as large energy fluxes in the cross equatorial region enhanced energy fluxes are therefore simulated at 20 30 km altitude over a region with no significant source of gravity waves and are confirmed using global positioning satellite meteorology gps met experiment data

a global view of stratospheric gravity wave hotspots located with atmospheric infrared sounder observations 1 the main aim of this study is to find and classify hotspots of stratospheric gravity waves on a global scale the analysis is based on a 9 year record 2003 to 2011 of radiance measurements by the atmospheric infrared sounder airs aboard nasa s aqua satellite we detect gravity waves based on 4 3 m brightness temperature variances our method focuses on peak events i e strong gravity wave events for which the local variance considerably exceeds background levels we estimate the occurrence frequencies of these peak events for different seasons and time of day and use the results to find local maxima or hotspots in addition we use airs radiances at 8 1 m to simultaneously detect convective events including deep convection in the tropics and mesoscale convective systems at middle latitudes we classify the gravity wave sources based on seasonal occurrence frequencies for convection but also by means of time series analyses and topographic data our study reproduces well known hotspots of gravity waves e g the andes and the antarctic peninsula however the high horizontal resolution of the airs observations also allows us to locate numerous mesoscale hotspots which are partly unknown or poorly studied so far most of these mesoscale hotspots are found near orographic features like mountain ranges coasts lakes deserts or isolated islands this study will help to select promising regions and seasons for future case studies of gravity waves

evolution of the alluvial fans of the luo river in the weihe basin central china controlled by faulting and climate change a reevaluation of the paleogeographical setting of dali man site abstract the luo river is located in the southern part of the chinese loess plateau and the northern part of the weihe basin in central china in the basin it flows proximal to the site of the luyang wetland core which is an important archive of climate change over the past 1 myr in this region in this paper the contribution of the luo river to the sedimentary record is analyzed by reconstructing the evolution of this river during the middle to late pleistocene it is argued that an alluvial fan of the luo river has contributed to the sedimentary archive until approximately 200 240 ka from this moment onwards the fan became incised and terraces began to form the formation of a new alluvial fan further downstream led to the disconnection of the luo river from the luyang wetland core site we propose that this series of events was caused by the displacement of an intra basinal fault and the resultant faulting forced folding which caused increased relative subsidence and thus increased sedimentation rates at the core site therefore a complete sediment record in the luyang wetland was preserved despite the disconnection from the luo river the chronology of the fans and terraces was established using existing age control u series esr osl pirir 290 and magnetic susceptibility correlation and through correlation of the loess paleosol cover to marine isotope stages based on sedimentological characteristics of the fluvial sequence we suggest that incision of the luo river occurred in two steps small incisions took place at transitions to interglacials and the main incision phases occur at the transition from an interglacial to glacial climate due to the incision basal parts of the oldest luo river alluvial fan are exposed and it is in one of these exposures that the famous dali man skull was retrieved this study shows that the dali man did not live on a river terrace as previously thought but on an aggrading alluvial fan during wet glacial conditions

loess stratigraphy in central china abstract loess sequences in central china provide a detailed record of climate changes during the last 2 5 million years at least 44 major shifts from glacial to interglacial conditions occurred during this time in china prolonged loess deposition lasting more than 40 millennia occurred eleven times with only four of these intervals in brunhes chron the climate oscillations took place with increased frequency between 2 4 and 0 5 ma compared to the last half million years major shifts toward cooler and drier climates occurred at about 2 4 ma 1 2 ma and 0 5 ma while less pronounced shifts are dated to 1 65 ma 0 8 ma and 0 2 ma three of the last four reversals of the earth s magnetic field whose lithostratigraphic position has been detail are recorded in a glacial deposit the low field magnetic susceptibility of loess and soils which reflects the concentration of ultrafine magnetite is related to the degree of pedogenesis and serves as a proxy measure of climate the accumulation rate of the magnetite was fairly constant throughout the last 1 2 million years and can serve as a measure of time susceptibility records from localities near xifeng and luochuan located 160 km apart are compared and used to define informal lithostratigraphic units in the loess plateau of china

the cenozoic tectonic evolution of the faulted basins in the northern margin of the eastern qinling mountains central china constraints from fault kinematic analysis abstract a series of ne and nw trending cenozoic faulted basins located at the north margin of the eastern qinling mountains document cenozoic intracontinental extension process in central china based on fault kinematic analysis of the faulted basins coupling with the stratigraphic sequence we rebuilt a tectonic stress sequence of the faulted basins since the cenozoic era combined with the previous chronological data we define the cenozoic faulted basin formation process including two stages of tectonic evolution the first stage largely presents the nw se extensional rifting in a long period from the paleocene to the middle late miocene due to northwestward subduction of the pacific plate it is marked by the basin occurrence along the north margin of the eastern qinling mountains e g the sanmenxia lushi shangluo and weihe basins in the paleocene to the early middle miocene in accordance with a nw se extension and regional basin inversion in the middle miocene as the result of a nw se compression the second stage is featured by the three episode extension since the middle late miocene which is probably affected by the combination of the northeastward growth of the tibetan plateau and the northwestward subduction of the pacific plate the earliest episode of nw se extension caused by regional ne sw compression in the late miocene to early pleistocene which leads to the formation of the yuncheng basin a gentle ne sw extension subsequently dominated here in the late pleistocene as represented by the widespread appearance of paleo lakes in the basins then the youngest tectonic regime controlled this region characteristic of a tectonic transpression ene sws compression and nnw sse extension causing evidently strike slip activities on the primary faults in the basins

source spectra information derived from u s high resolution radiosonde data 1 a ray tracing model is used to study the climatology of the source properties for gravity waves in the lower stratosphere using 8 years of u s high resolution radiosonde data if the simulated total energy density and zonal momentum flux correlate well with those two parameters derived from the observations simultaneously we claim a best fit is found eighty five stations with sufficient completeness and quality are analyzed and we are able to obtain best fit source spectra for 61 of them two conditions are found to be necessary to achieve a best fit first the kinetic energy density and the zonal momentum flux derived from observations need to be highly correlated second the source altitude needs to be located right below the lower stratosphere since the observed gravity waves represent the average climatology of the cumulative effect on a monthly average basis of the various time varying physical sources together with their propagation from different altitudes all the sources we found are anisotropic with most of momentum flux directed upstream of the dominant wind direction this might be caused by wave propagation effects or the nature of the sources themselves the latitudinal variation of the horizontal wavelength of the source spectra corresponds well with that derived independently from the observations but other variable parameters do not show obvious latitudinal dependence a source spectrum type representing convection works well for lower latitudes while another more general source works better for middle to high latitudes the central u s and the north american monsoon region are two regions where it is difficult to obtain best fit source spectra we suspect that the reason for this is that during the summer mesoscale convective systems are dominant sources for inertia gravity waves which may not be well represented by our chosen spectral source functions

stacked 2 6 ma grain size record from the chinese loess based on five sections and correlation with the deep sea δ18o record 1 this study aims to establish a stacked climate record of the quaternary period from the chinese loess sequence and to address the forcing mechanisms for the regional climate history of the loess plateau by correlating the stacked record with a composite 18o record in deep sea sediments a total of 18 352 samples were obtained from five loess sections located at baoji lingtai jingchuan puxian and pingliang in the southern and middle loess plateau these yielded high resolution grain size records between section correlation of these shows that although small depositional hiatuses are present in places within a single section most parts of the sections display near continuous dust deposition throughout the quaternary the grain size records were tuned simultaneously to the theoretical variations in obliquity and precession of the earth s orbit the grain size records plotted on their orbital timescales were then averaged to form a stacked loess grain size time series termed the chiloparts record this resolves most of the orbital timescale paleoclimate events buried in the loess soil sequences of the southern and middle loess plateau and can be used as a regional archive of the pleistocene climate history in the loess plateau comparison of the chiloparts record with a composite marine 18o record shows that for the past 1 8 ma the loess paleosol record can be correlated almost cycle by cycle with the marine record several discrepancies in the climatic events between the two records have also been identified implying that regional forcing mechanisms may have played a part in the climatic evolution of the chinese loess plateau

seasonal variation of momentum flux in the mesosphere observed with the mu radar we have regularly monitored mesospheric winds at 60 85km for three years with the mu radar 35 n 136 e and have found that the variance of wind velocity fluctuations for periods from 5 min to 2 hr shows a semi annual variation with a significant peak in summer centered in july and irregular enhancements in winter the zonal momentum flux induced by gravity waves shows eastward and westward maxima in july august and december february respectively typical eastward accelerations at the 70km altitude range from 7 to 13 m s day and from 8 to 11 m s day in summer and winter respectively which agree fairly well with theoretical predictions

simulation of the eastward 4 day wave in the antarctic winter mesosphere using a gravity wave resolving general circulation model 1 the eastward moving 4 day wave in the antarctic winter mesosphere is investigated using a high resolution middle atmosphere general circulation model that directly simulates the spontaneous generation propagation and dissipation of gravity waves the results are also compared with the simulated seasonal march of the meridional structures of the westerly jet streams in the southern hemisphere upper stratosphere and mesosphere in order to investigate baroclinic barotropic instability as a possible excitation mechanism for the 4 day wave the model successfully reproduces the dynamically unstable double jet structure of the mesospheric westerly winds the simulated 4 day wave develops in association with the baroclinic and barotropic instability of the mesospheric mean flows and has similar characteristics to those observed at 50 60 s near the stratopause the 4 day wave has strong equatorward heat flux associated with strong baroclinicity in the antarctic winter mesosphere mainly attributable to poleward overturning circulation driven by gravity wave forcing eastward forcing due to the 4 day wave occurs within the double jet structure and offsets part of the westward forcing due to gravity waves such an effect partially acts to stabilize the unstable mean flow structure in the antarctic winter mesosphere

seasonal variation of gravity wave activity at 5 20 km observed with vhf radar at white sands missile range new mexico wind observations at altitudes from 5 to 20 km obtained from the vhf wind profiler radar at the white sands missile range ws new mexico are used to construct a climatology of gravity wave intensities over ws during the nearly 6 year period from january 1991 through september 1996 the kinetic energy densities for both high frequency gravity waves ground based period of 6 min to 2 hours and low frequency gravity waves period from 2 to 21 hours are considered these results are compared to earlier results from the middle and upper atmosphere mu radar in japan comparisons of gravity wave variability at high and low frequency reveal both similarities and differences between the two sites the primary differences occur at high frequency the seasonal cycle in the high frequency gravity waves is less pronounced and less regular at ws compared to mu the magnitude of the high frequency kinetic energy density is generally larger at ws compared to mu and the relationship between the upper tropospheric jet stream winds and the high frequency gravity wave activity is not nearly so strong at ws as at mu the primary high frequency gravity wave excitation mechanism at ws appears to change with season there is evidence of a connection in winter and spring between the wind speeds in the middle troposphere and the high frequency gravity wave activity suggesting a topographic source for these waves strong summertime high frequency variability at ws in the upper troposphere is most likely linked to waves launched by deep convection during the monsoon season in new mexico the results for low frequency gravity waves are more consistent between ws and mu similarities appear in the kinetic energy density the nature of the seasonal cycle and the correlation between the kinetic energy density and the mean winds

vhf radar observations of gravity wave production by cold fronts over southern australia abstract four extended observational campaigns were conducted during august and november 1988 with an st stratosphere troposphere radar in southern australia during the passage of cold fronts over the system giving around 30 days of three dimensional wind measurements with 15 min time and 0 5 km height resolution over the 2 11 5 km height range order of magnitude increases in the variance of time fluctuating wind velocities were measured during frontal passages which are definitively ascribed to gravity waves the time height morphology of the horizontal and vertical velocity fluctuations differed bursts of horizontal velocity variance u 2 2 10 100 m2 s 2 arose at upper levels about a day before the frontal boundary arrived and this activity gradually extended to lower heights as the front neared the arrival of the frontal boundary marked a sudden reduction in this activity after the frontal boundary passed reduced activity persisted for 12 hours after which bursts in u 2 2 returne

tectonic activity and structural features of active intracontinental normal faults in the weihe graben central china abstract this study examines the tectonic activity and structural features of active normal faults in the weihe graben central china the weihe graben is an area with a high level of historic seismicity and it is one of the intracontinental systems that developed since tertiary in the extensional environment around the ordos block analysis of high resolution remote sensing imagery data field observations and radiocarbon dating results reveal the following i active normal faults are mainly developed within a zone

deduction of the age of the dali hominin fossil based on regional geomorphic sedimentary evolution abstract dali hominin an archaic type of early homo sapiens is of great significance to the understanding of the evolutionary processes of homo sapiens in china however its age remains debatable there developed a series of lacustrine and alluvial terraces both in the northeastern part of the weihe basin and in the stretch of the luo river near the dali hominin site and the dali hominin cranium fossil was yielded from the basal alluvium of t3 of the luo river the paper first adopted the loess paleosol sequence dating method to determine the age of each terrace in order to delineate the history of the regional paleolake regression transgression cycles then in combination with the characteristics of the geomorphic sedimentary body bearing the dali hominin fossil the paper verified which paleolake regression transgression cycle is represented by the fossil bearing deposits last based on grain size and pollen evidences from this geomorphic sedimentary body the paper deduced the age of the cranium bearing bed the results show that there occurred several paleolake regressions and river down cutting events when s14 l9 l6 s2 l2 and l1ss developed or accumulated respectively and that the alluvium bearing the cranium fossil was deposited after the paleolake regression in the late stage of l6 deposition this regression caused parts of the paleolake bed to emerge subaerially and the luo river subsequently flowed over it eroding the lacustrine sediment and depositing alluvium the deposition of this alluvium was therefore probably synchronous with the development of s5 with a mean age of 550 ka by comparison with homo heidelbergensis at mauer germany in both the living paleoenvironment and the age the paper found that both hominin may be penecontemporaneous

small scale motions observed by aircraft in the tropical lower stratosphere evidence for mixing and its relationship to large scale flows abstract measurments of temperature and ozone from instrumental aircraft in the tropical lower stratosphere show the presence of small scale disturbances generated by 1 underlying cumulus convection and 2 kelvin helmholtz instability the disturbances associated with underlying convection have peak to peak vertical parcel excursions of 300 m flying conditions were smooth suggesting an ensemble of gravity waves and little or no turbulent mixing it is nevertheless possible that these waves break at other altitudes leading to turbulent mixing and net fluxes of vertically stratified tracers disturbances attributed to kh instability implied vertical parcel excursions of 300 400 m the disturbances coincided with rough flying conditions suggesting turbulent mixing a linear stability analysis of the atmospheric basic state defined by high resolution radiosondes shows fastest growing waves with horizontal wavelengths of 1 4 1 8 km consistent with the aircraft observations the strong shears responsible

gravity waves in the tropical lower stratosphere a model study of seasonal and interannual variability a model study is presented to clarify the relationship between gravity wave properties observed in the stratosphere and the sources for the waves presumed to be in the troposphere the observations are balloon borne radiosondes launched from cocos island in the tropical indian ocean 12 s 97 e and the analysis of these data is described in a companion paper vincent and alexander this issue the dominant time variations in the observed gravity wave activity are annual and quasi biennial patterns in the zonal momentum flux and kinetic energy density the background zonal winds at this site vary with the same periods and these are known to be capable of causing dramatic variations in the observable properties of the waves even if the sources for the waves are constant in time the results presented here clarify 1 the nature of the sources for the gravity waves observed in the stratosphere 2 the limitations of the observations for observing the full range of gravity wave perturbations potentially present in the atmosphere and 3 the role the observed waves can play in forcing the quasibiennial oscillation qbo in the zonal winds at this latitude the stratospheric waves appear to originate near the height of the tropopause so the source is apparently related to deep convection no seasonal or interannual variations in the convection need be assumed to understand the observations the waves at the tropopause appear to have a phase speed distribution that is narrowly confined near zero phase speed relative to the ground the source is likely related to slowly propagating tropospheric convection and the wind near the tropopause variations observed in the stratospheric data are caused by both the wind shear in the stratosphere and the ability of waves with these characteristics to propagate vertically without severe dissipation higher phase speed waves may be present and could carry significant momentum flux vertically into the stratosphere and mesosphere but would be extremely difficult to see in these radiosonde data the observed waves can contribute substantially to the descent of the eastward shear zones characteristic of the westerly phase of the qbo in the lower stratosphere zonal winds

a statistical study of inertia gravity waves in the troposphere based on the measurements of wuhan atmosphere radio exploration ware radar wuhan atmosphere radio exploration ware radar is the first mesosphere stratosphere troposphere radar to have become operative in the mainland of china and is dedicated to real time atmospheric observations based on the ware radar data collected for the period from september 2011 to february 2013 2666 downward and 1735 upward inertia gravity waves igws are identified from three dimensional 3 d wind fields observed in the troposphere and subsequently analyzed in a statistical manner wave characteristics including intrinsic frequencies vertical wavelengths horizontal wavelengths vertical wave number spectra energy density spectra and wave sources are investigated using a combination of the lomb scargle spectral analysis the quasi monochromatic gravity waves model and the hodograph method our results demonstrate that the characteristic parameters of upward and downward tropospheric igws are not significantly different these results indicate that the tropospheric igws parameters are not directly correlated with propagation directions combining with the information of statistical 3 d wind field and some climatic characteristics of hubei province atmospheric moist convection will contribute most in summer whereas jet front systems will contribute most in winter one may expect seasonal variations to be tied to the varying importance of these sources

global estimates of equatorial inertia gravity wave activity in the stratosphere inferred from era40 reanalysis 1 a new methodology is applied to era40 reanalysis in order to quantify large scale inertia gravity wave activity in the equatorial lower stratosphere both eastward and westward propagating waves are identified in the data set and a good agreement is found with previously published in situ observations global estimates of vertical fluxes of zonal momentum associated with such waves are obtained typical amplitudes of order 10 2 m2 s 2 suggest that the forcing of the quasi biennial oscillation by large scale inertia gravity waves is tantamount to that by kelvin waves this method can be used to document the space time variability of the wave activity in order to improve the wave drag parameterizations in climate models

clouds at the tropical tropopause a case study during the ape theseo campaign over the western indian ocean in this paper we report a detailed description of a thin cirrus at the tropopause above a cumulonimbus cb convective cluster observed during the airborne platform for earth observation third european stratospheric experiment for ozone ape theseo campaign in february march 1999 in the western indian ocean the thin cirrus ci has an optical depth at 532 nm below 0 1 with extended subvisible stretches and is located directly below the tropopause which was supersaturated with respect to ice a direct comparison between the optical depth retrieved by meteosat and that obtained by means of the hygrometers installed on the m55 geophysica aircraft is discussed showing discrepancies ranging from 10 to 20 combining satellite and aircraft data we show that the observed ci is not due to cirrus outflow from cb anvils in the absence of any deeply convective clouds reaching altitudes above 15 km we propose a possible mechanism of ci formation based on a net mesoscale transport of water vapor from altitudes above 16 km to the tropopause region around 18 km this transport could be driven by the critical layer and turbulence induced by gravity waves that could have been generated by lower level cb cluster activity the proposed mechanism for high altitude ci formation corroborates the new paradigm of a tropical tropopause layer ttl or substratosphere several kilometers thick which is decoupled from the convection dominated lower troposphere

cyclic quaternary alluviation and terracing in a nonglaciated drainage basin on the north flank of the qinling shan central china abstract pleistocene alluvial terraces of the nonglaciated ba river drainage basin on the north flank of the qinling shan are capped by a succession of loess units and paleosols that correlate with the standard marine isotope chronology and are used to date the subjacent alluvial gravels alluvial fills were deposited during isotope stages 2 6 8 12 and 16 whereas terracing occurred during interglacial stages 1 5 7 11 and 15 the apparent absence of terraces dating to stage 14 and stage 4 may be due to the lesser intensity of these glaciations compared to that of stage 2 although disruption of the alluvial regime by local tectonism is a likely alternative for the lack of a stage 4 terrace a stage 10 terrace was not positively identified from available exposures its possible absence could be related to post stage 12 uplift aggradational episodes correlate with glaciations and loess deposition whereas degradational episodes correlate with interglaciations or interstades and soil formation implying that climate is the primary control on quaternary paleohydrology this in turn points to variations in the earth s orbital geometry as the major factor that modulates both climate and ultimately the fluvial system in the qinling shan in this region glaciations were dominated by a cold dry winter monsoon climate whereas during interstades and interglaciations a warmer and wetter climate prevailed implying strengthening of the summer monsoon both the loess paleosol and the alluvial records are consistent with climate model simulations spanning the last 18 000 yr that show a change from cold dry conditions during the last glacial maximum to a climate warmer and wetter than present during the first half of the holocene

gravity waves in the tropical lower stratosphere an observational study of seasonal and interannual variability radiosonde observations made at cocos islands 12 s 97 e in the indian ocean between september 1992 and june 1998 are used to study seasonal and interannual variations in gravity wave activity in the lower stratosphere 18 25 km the islands are located in a region of generally strong convection that occurs at all times of the year with the period of strongest convective activity between december and july wet season the prevailing zonal winds during the observational period and height range are westward with a quasi biennial oscillation qbo superimposed time series of wave energy show that largest wave amplitudes occur during the wet season when convection is strongest but a qbo like variation is also apparent maximum energy densities of about 25 j kg 1 occur early 1993 1995 and 1997 at the times when the westward shears are largest wave energy is found to be propagating upward and in the horizontal there is considerable azimuthal anisotropy with predominate eastward propagation against the prevailing wind upward fluxes of zonal momentum flux u w are estimated by combining the temperature and wind information fluxes show a similar temporal behavior to the energy the motion and temperature fields are dominated by waves with vertical wavelengths 2 km using a stokes parameter analysis it is found that the intrinsic frequencies are on average 2 3 times the inertial frequency corresponding to intrinsic periods of 20 25 hours horizontal wavelengths between 200 and 2000 km are inferred with a mean value of about 1000 km the mean intrinsic phase speeds are about 10 ms 1 but ground based phase speeds are centered on 0 ms 1

stratospheric variability of wave activity and parameters in equatorial coastal and tropical sites during the west african monsoon recent numerical studies in stratospheric dynamics and its variability as well as climate have highlighted the need of more observational analyses to improve simulation of the west african monsoon wam in this paper activity and spectral characteristics of short scale vertical waves wavelengths 4 km are analysed in equatorial coastal and tropical lower stratosphere during the wam a first detailed description of such waves over west africa is derived from high resolution vertical profiles of temperature and horizontal wind obtained during intensive observation period of the african monsoon multidisciplinary analyses amma campaign 2006 monthly variation of wave energy density is revealed to trace the progression of the inter tropical convergence zone itcz over west africa mesoscale inertia gravity waves structures with vertical and horizontal wavelengths of 1 5 2 5 and 400 1100 km respectively and intrinsic frequencies of 1 1 2 2 f or periods 2 days are observed in the tropical ls with intense activity during july and august when the wam is installed over the tropical west africa over equatorial region gravity waves with intrinsic frequencies of 1 4 4 f or periods 5 2 days vertical wavelength of 2 1 km and long horizontal wavelengths of 1300 km are intense during the wam coastal phase from july to october gravity waves with intrinsic frequencies of 1 2 3 8 f or periods 6 days vertical wavelength of 2 1 km and horizontal wavelengths of 1650 km are less intense during the wam sahelian phase of the wam march june unlike potential energy density kinetic energy density is observed to be a good proxy for the activity of short scale vertical waves during the wam because quasi inertial waves are dominant long term wave activity variation from january 2001 to december 2009 highlights strong year to year variation superimposed on convective activity and quasi biennial oscillation like variations especially above tropical stations

tt osl and post ir irsl dating of the dali man site in central china abstract showing features associated with archaic homo sapiens and evolved homo erectus the dali skull is a key fossil for understanding human evolution in china various dating methods such as u series irsl tl esr esr u series and stratigraphical correlation with central loess plateau sequence were used to estimate the antiquity the dali man site with varying results in this study a total of 12 samples were taken in the sequence in the dali man site from the aeolian loess palaeosol sequence and underlying fluvial deposit layers including the palaeoanthropological level and dated by several optically stimulated luminescence osl methods coarse grained quartz sar osl thermally transferred osl tt osl and k feldspar post ir infrared ir stimulated luminescence post ir irsl pirir 290 methods results show that the tt osl and pirir 290 ages were consistent up to 100 ka for older samples the feldspar ages were significantly older these pirir 290 ages increased with the stratigraphy up to 310 ka the best age estimation of the dali man layer providing by the feldspar pirir 290 suggested that the dali man lived in late period of l3 mis 8 stage furthermore correlating the pirir 290 ages between 267 7 13 9 ka and 258 3 14 2 ka and new pollen analysis we proposed a new viewpoint that the dali man was likely to live during a transitional period from glacial to interglacial climate in the s2 l3 mis 7 8 stage

jicamarca radar observations of the diurnal and semidiurnal tide in the troposphere and lower stratosphere 1 the mesosphere stratosphere troposphere mst radar at jicamarca peru 12 s 77 w made extended 15 day or longer observations of the horizontal and vertical winds that were used to infer the diurnal and semidiurnal tides the measurements were made during several months from mid 1997 through mid 1998 and using a higher power transmitter and finer range resolution during 10 days of august 1998 the three component winds are used to estimate amplitudes phases and momentum fluxes associated with the tides thermal forcing of the diurnal tide is also examined with diurnal water vapor heating rates calculated using data from the nasa water vapor project nvap for the region near jicamarca the calculations from nvap showed the temporal variability of the diurnal heating to be dominated by an annual cycle with maximum around the summer solstice when projected into tidal modes about 25 of the total water vapor heating rate amplitude near jicamarca is found to be nonmigrating the meridional amplitude of the semidiurnal tide was found to be generally greater than the zonal amplitude although tidal theory predicts that the zonal amplitude should be much greater at the latitude of jicamarca assuming the tide was migrating the phase of the semidiurnal tide lagged by about 3 hours the phase expected from surface pressure climatologies according to tidal theory the migrating semidiurnal tide should transport little meridional momentum flux however substantial southward fluxes v w 1 10 3 m2 s 2 were observed at jicamarca and the meridional component of momentum flux was typically larger in magnitude than the zonal component was the diurnal tide was somewhat weaker was less coherent and transported less momentum the semidiurnal tide had a very long vertical wavelength throughout the troposphere and into the lower stratosphere while the diurnal tide was only observed to propagate at heights above the tropopause with a much shorter 10 km vertical wavelength below the tropopause the dominant diurnal motions were not traveling waves but rather convective motions that exhibited little phase progression with altitude these motions were broadly peaked in frequency around 24 hours and were presumably standing oscillations with no horizontal propagation and probably with small horizontal scale despite the lack of coherence of these quasi diurnal motions the associated vertical wind amplitudes were sizable 0 02 m s 1 and thus the fluctuations can presumably transport significant horizontal momentum

gravity wave generation in the lower stratosphere due to passage of the typhoon 9426 orchid observed by the mu radar at shigaraki 34 85 n 136 10 e 1 intense gravity wave activities were investigated in the lower stratosphere during the typhoon 9426 strong vertical winds were observed just a few hours before the arrival of the typhoon center at the mu radar site about 30 min to 1 hour after the typhooncenter had passed a considerable reduction in vertical wind amplitude was detected dominant gravity waves showed time period in the range of 7 8 min 15 min and 40 60 min in the upper troposphere and lower stratosphere in the vicinity of the central region of the typhoon a gravity wave was observed which was monochromatic in nature with a vertical wavelength 3 km between 1 5 km and 23 km height in the lower stratosphere the horizontal wavelength for the prominent period was detected in the range of 10 15 km for 15 min wave period and 25 50 km for 40 60 min wave period the vertical wavelength of these waves was examined from 2 5 km to 4 0 km in the horizontal direction the intrinsic group velocity was estimated between 9 2 and 11 2 m s near the tropopause the average direction of group velocity was assessed at about 20 3 from the horizontal the generation of gravity wave like features in the lower stratosphere is believed induced by convection as the low temperature of the clouds indicates a deep penetration over the radar region as seen in the satellite gms images index terms 3314 meteorology and atmospheric dynamics convective processes 3334 meteorology and atmospheric dynamics middle atmosphere dynamics 0341 0342 3329 meteorology and atmospheric dynamics mesoscale meteorology 3384 meteorology and atmospheric dynamics waves and tides 6952 radio science radar atmospheric physics keywords convective updrafts gravity waves troposphere lower stratosphere

vertical wind disturbances in the troposphere and lower stratosphere observed by the mu radar abstract an analysis is made of vertical wind disturbances vwds observed by the mu radar shigaraki shiga japan in terms of the wave structures sources and vertical momentum flux first it is shown through spectral and lag correlation analyses that there are several common features in three observation periods when the vwds appeared large power in the vertical wind fluctuations exists below a height of 20 km and is distributed largely at lower frequencies the decrease in power near 20 km is sharp and the correlation between vertical winds above and below the level is very small suggesting that the height of 20 km is a special level for the vwds such as a critical level the disturbances below 20 km consist of several modes in a height frequency space some of which oscillate almost in phase in a wide height range spanning 8 km at the maximum second using eight sets of the mu radar data the relationship between vertical wind activity and horizontal wind near the surface is examined in order

climate control on the palaeo lake evolution in the southern datong basin north china evidence from 800 ka core records integrated sedimentological and clay mineral analyses of a 300 m depth core reveal the history of the palaeo lake and palaeoclimatic evolution of the southern datong basin over the past 800 ka the sedimentary facies including deep lake shallow lake alternation of lakeside and shallow lake and the river environment are identified based on the general characteristics of the grain size analysis two episodes of warm humid events are responsible for the palaeo lake expansion during the period of 800 480 ka corresponding to the presence of s7 s6 and s5 in the loess plateau a stepwise cooling and drying trend since approximately 480 ka is strongly linked to the gradual shrinkage and extinction of the palaeo lake our results demonstrated that climate change has played an essential role on the palaeo lake expansion shrinkage during the middle pleistocene breaching of shixia gorge by active neotectonic movement since the middle late pleistocene enhanced the shrinkage and extinction of the palaeo lake coupled with a cold dry climate in the last glacial the climatic changes documented by clay minerals and grain size parameters in the datong basin are consistent with the loess paleosol sequences in the loess plateau and fluvio lacustrine sediments in the nihewan basin mainly controlled by the east asian monsoon in response to the regional global change since the mid late pleistocene

a modeling study of stratospheric waves over the southern andes and drake passage abstractlarge amplitude stratospheric gravity waves over the southern andes and drake passage as observed by the atmospheric infrared sounder airs on 8 9 august 2010 are modeled and studied using a deep 0 70 km version of the coupled ocean atmosphere mesoscale prediction system coamps model the simulated tropospheric waves are generated by flow over the high central andes ridge and the patagonian peaks in the southern andes some waves emanating from patagonia propagate southeastward across drake passage into the stratosphere over a horizontal distance of more than 1000 km the wave momentum flux is characterized by a tropospheric maximum over patagonia that splits into two comparable maxima in the stratosphere one located directly over the terrain and the other tilting southward with altitude using spatial ray tracing techniques and flow conditions derived from the numerical simulation the authors find that waves that originate from the high ridge in the central andes are absorbed by a critica

characteristics of atmospheric gravity wave activity in the polar regions revealed by gps radio occultation data with champ 1 using gps radio occultation data during 2001 2005 we studied the climatological behavior of atmospheric gravity waves in the polar stratosphere we calculated temperature fluctuations with vertical wavelengths shorter than 7 km and then determined the wave potential energy ep every month in a longitude latitude cell of 20 10 between 12 km and 33 km in the arctic region 50 90 n ep shows an annual variation with maximum in winter consistent with the zonal mean horizontal wind v and the eliassen palm e p flux fz the large fz values indicate higher planetary wave activity resulting in distortion of the polar vortex the unbalanced flow can then excite gravity waves through geostrophic adjustment in the antarctic region 50 90 s ep gradually increases during winter and reaches its maximum in spring before decreasing rapidly the time derivative of v coincides with the ep peak and the horizontal distribution of ep has a similar structure to v suggesting that the ep enhancement is closely related to the decay of the polar vortex during major warming events over the arctic the divergence of e p flux f was enhanced coinciding with large ep in the antarctic f strongly correlates with ep in spring gravity waves seem to be effectively generated through planetary wave transience and or breaking orographic generation of gravity waves seems to be important in limited areas only such as scandinavia and the antarctic peninsula showing that it is less important than the polar night jet in determining the climatological behavior of gravity waves

characteristics of kelvin waves and gravity waves observed with radiosondes over indonesia profiles of wind velocity and temperature at 0 35 km were observed by means of radiosondes in west java indonesia during november 1992 and april 1993 and used to study the behavior of various atmospheric waves in the equatorial atmosphere an oscillation of zonal winds with a period of about 27 days was found in the troposphere which was associated with variations in humidity and cloud top height kelvin waves showed phase progression beginning at cloud top height 13 16 km and were particularly enhanced near the tropopause the kelvin waves strongly modulated the tropopause structure including the tropopause height minimum temperature and atmospheric stability a hodograph analysis was applied to determine the propagation characteristics of inertial gravity waves height variation of the vertical group velocity suggests that the gravity waves were generated in the troposphere while the horizontal phase velocity distribution suggests that they were interacting with the background mean zonal winds these wave activities were enhanced when tall convective clouds passed over the site suggesting that cumulus convection seems to play a key role in generating these waves in the equatorial region

balloon borne observations of short vertical wavelength gravity waves and interaction with qbo winds the quasi biennial oscillation qbo a ubiquitous feature of the zonal mean zonal winds in the equatorial lower stratosphere is forced by selective dissipation of atmospheric waves that range in

geomorphological observations of active faults in the epicentral region of the huaxian large earthquake in 1556 in shaanxi province china abstract the huaxian magnitude 8 great earthquake of january 23 1556 is the largest one recorded in the weihe basin shaanxi province china and caused 830 000 people either injury or death the epicenter is located in the southeastern part of the weihe basin around huaxian city earthquakes are closely related to active faults and active faults are well developed in the epicentral area of the huaxian large earthquake thus we will discuss the activity of the major faults in the epicentral area by geomorphological observations there are three major fault sets in the study area striking approximately east west northeast and northwest these are inhomogeneous in spatial distribution rates and manners of faulting as shown by geomorphological observations such as faulted fluvial terraces and alluvial fans the ages of the second and first terraces are around 20 000 and 5 000 years b p by thermoluminescent dating carbon 14 dating and archeology the terraces were faulted by the north huashan fault f1 the main boundary fault of weihe basin and the piedmont fault f2 after the second and the first terraces formed the distribution of the displacement shows that the intersections of the north huashan fault and the chishui fault f4 striking northwest and the western margin fault f5 of tongguan loess tableland have the largest in offsets in the area perhaps the huanxian great earthquake in 1556 a d had a close relation to the north huashan fault the weihe fault f3 striking east west is also an active fault by analysis of the flood plain structure thus we should pay attention to the activities of the faults to take precautions against another possible large earthquake in this region

sources of mesoscale variability of gravity waves part i topographic excitation abstract aircraft measurements of winds and temperatures collected during the gasp program are used to study the effects of topography as a source of mesoscale variability variances of fluctuations at the mesoscale over rough terrain are enhanced up to nearly two orders of magnitude compared to nonsource regions in some cases and are frequently enhanced by an order of magnitude the implications of these episodic enhancements of variances for the vertical transports of energy and momentum are considered in the framework of gravity wave theory the observed flight data are used to estimate the momentum flux u w on several flight segments results show that the flux is generally negative with mean value 0 26 m2 s 2 and with magnitudes ranging up to 1 5 m2 s 2 spectral analysis shows that the largest contributions to the net flux come from horizontal scales of 25 x 60 km finally the observed momentum fluxes are used to infer the anisotropy factor of gravity waves over rough terrain which is foun

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

gravity wave activity associated with tropical convection detected in toga coare sounding data upper air sounding data collected at santa cruz 10 s 165 e in the western tropical pacific ocean during november 1992 february 1993 have been used to estimate the gravity wave activity in the upper troposphere and lower stratosphere large amplitude gravity waves with vertical wavelengths of 2 5 km were found in almost all the soundings time series describing the wave activity in two height ranges 10 17 km the upper troposphere and 17 24 km the lower stratosphere are presented and compared to simple measures of the convective cloud activity there is enhanced gravity wave activity associated with increased convection on intraseasonal timescales

vertical fluctuation energy in united states high vertical resolution radiosonde data as an indicator of convective gravity wave sources 1 convectively generated internal gravity waves at extratropical latitudes are difficult to identify by climatological analysis of the temperature and horizontal wind fields from radiosonde profiles using traditional analysis methods here we show that by analyzing ascent rate profiles we define a new variable vertical fluctuation energy ve we can identify convection sources in climatological analyses analysis of a 9 year time series 1998 2006 of united states high vertical resolution radiosonde data shows that ve maximizes in summer in midlatitudes within the troposphere 2 8 9 km and peaks at local afternoon early evening during the summer over most of the contiguous united states furthermore the apparent dominant vertical wavelength based on fourier analysis of the low pass filtered ascent rate fluctuations also increase and decrease with ve both on diurnal and seasonal timescales ve in the lower stratosphere however does not show this same relationship to convection but analysis of the vertical wavelength does show some of the features seen in tropospheric ve unlike midlatitude stations ve within both the troposphere and the lower stratosphere over tropical western pacific island stations is highly correlated with convective precipitation and inversely correlated with outgoing longwave radiation we interpret this difference by using the 4 d gravity wave regional or global ray tracer ray tracing model with a source spectrum representative of a convection source

convectively coupled equatorial waves 1 convectively coupled equatorial waves ccews control a substantial fraction of tropical rainfall variability their horizontal structures and dispersion characteristics correspond to matsuno s 1966 solutions of the shallow water equations on an equatorial beta plane namely kelvin equatorial rossby mixed rossby gravity and inertio gravity waves because of moist processes the tilted vertical structures of ccews are complex and their scales do not correspond to that expected from the linear theory of dry waves the dynamical structures and cloud morphology of ccews display a large degree of self similarity over a surprisingly wide range of scales with shallow convection at their leading edge followed by deep convection and then stratiform precipitation mirroring that of individual mesoscale convective complexes ccews have broad impacts within the tropics and their simulation in general circulation models is still problematic although progress has been made using simpler models a complete understanding of ccews remains a challenge in tropical meteorology

characteristics of atmospheric wave induced laminae observed by ozonesondes at the southern tip of south america articulo publicado en la revista journal of geophysical research atmospheres no 123 p 1 19 2018

tropospheric turbulence over the tropical open ocean role of gravity waves a large set of soundings obtained in the indian ocean during 3 field campaigns is used to provide statistical characteristics of tropospheric turbulence and its link with gravity wave gw activity the thorpe method is used to diagnose turbulent regions of a few hundred meters depth above the mixed layer turbulence frequency varies from 10 in the lower troposphere up to 30 around 12km heights gw are captured by their signature in horizontal wind normalized temperature and balloon vertical ascent rate these parameters emphasize different parts of the wave spectrum from longer to shorter vertical wavelengths respectively composites are constructed in order to reveal the vertical structure of the waves and their link with turbulence the relatively longer wavelength gw described by their signature in temperature gwt are more active in the lower troposphere where they are associated with clear variations in moisture turbulence is then associated with minimum static stability and vertical shear stressing the importance of the former and the possibility of convective instability conversely the short waves described by their signature in balloon ascent rate gww are detected primarily in the upper troposphere and their turbulence is associated with a vertical shear maximum suggesting the importance of dynamic instability furthermore gww appear to be linked with local convection whereas gwt are more active in suppressed and dry phases in particular of the madden julian oscillation these waves maybe associated with remote sources such as organized convection or local fronts such as those associated with dry air intrusions

characteristics of inertia gravity waves over gadanki during the passage of a deep depression over the bay of bengal 1 using mst radar located at the indian tropical station of gadanki 13 5 n 79 2 e near the eastern coast of india studies have been made on the characteristics of inertia gravity waves generated in the lower troposphere during deep depression developed over the bay of bengal on 20 24 june 2007 filtering and the hodograph analyses of horizontal winds indicate that the low pressure system has generated inertia gravity waves propagating outward from the core of the depression strong enhancement of radar reflectivity snr in the heights of 4 7 km for a few days around 22 june 2007 and the upward propagation of gravity wave energy above this height range indicate that the source of the waves is located at 4 7 km this is in agreement with earlier theoretical expectations the vertical and horizontal wavelengths of gravity waves are found to be 2 2 km and 240 km respectively in the troposphere

age of the fossil dali man in north central china deduced from chronostratigraphy of the loess paleosol sequence dali man an archaic type of early homo sapiens is of great significance to the origin of homo sapiens achievements have been made during the past decades in the understanding of the fossil human skull as well as the accompanying mammalian fossils and stone artifacts however the absolute age of the fossil dali man still remains unclear based on the magnetic susceptibility of loess sediments and the relationship of terracing process with climatic condition we correlated the loess sequence and the subjacent terrace alluvium at the dali man site with the well studied loess paleosol sequence at luochuan in the central part of the chinese loess plateau the correlation indicates that the loess paleosol sequence at the dali man site extends down to the paleosol s2 and the underlying fluvial deposits correspond to the loess u because the dali man skull appears in the basal gravel layer of the terrace and because the deposition of the terrace gravels would occur during the transition from s3 paleosol formation to l3 loess accumulation the age of the fossil dali man is inferred to be ca 270 ka which is equivalent to the age of the boundary between the loess l3 and paleosol s3 on the magnetic susceptibility time series of the luochuan loess paleosol sequence c 2002 elsevier science ltd all rights reserved

mean winds and momentum fluxes over jicamarca peru during june and august 1987 abstract data from the mesosphere stratosphere troposphere mst radar at jicamarca peru together with other available data are used to diagnose the mean structure of winds and gravity wave momentum fluxes from the surface to 90 km during two ten day campaigns in june and august of 1987 in the stratosphere a layer of maximum eastward flow associated with the quasi biennial oscillation qbo was seen to strengthen and descend rapidly from june to august overlying persistent westward flow a layer of enhanced signal return suggestive of a turbulent layer was observed just above the descending qbo eastward maximum notable zonal asymmetries were present during this transition and the local meridional circulation departed from zonal mean qbo theory a substantial northeastward momentum flux was found below 25 km which may be related to topographic gravity waves excited by southeastward flow across the andes in the lower mesosphere a relatively weak second mesopause semiannual oscillation is confirm

records of human occupation from pleistocene river terrace and aeolian sediments in the arneiro depression lower tejo river central eastern portugal abstract in the uppermost reach of the lower tejo river eastern central portugal where the river crosses two quartzite ridges that separate the rodao upstream and arneiro downstream depressions palaeolithic artefacts have been recovered from three lower river terrace levels and a cover unit of aeolian sands this paper presents data on the discovery of archaeological artefacts from the terrace levels and the aeolian sands that can be linked to middle and upper palaeolithic industries from new field sites at tapada do montinho and castelejo the archaeological data when placed in a geomorphological sedimentary and chronological framework contribute new information on the understanding of human occupation in western iberia during cold climate episodes of the last 62 to 12 ka and especially during the cooler and driest conditions that occurred between 32 and 12 ka when the climate favoured aeolian sediment transport in the lower tejo river the integration of absolute age datasets with archaeological geomorphological and sedimentary data indicate that in westernmost iberia the first appearance of artefacts in river terrace sediments suggests that the earliest marker for human occupation dates from the lower acheulian lower palaeolithic probably corresponding to an age of 340 ka data also suggest for the first time that acheulian lithic industries were replaced by middle palaeolithic ones namely the levallois stone knapping technique by 160 ka mis6 middle palaeolithic industries were later replaced by upper palaeolithic industries at 32 ka the post 32 ka period dominated by aeolian sediment transport is related to the onset of cold dry climate conditions which resulted in low river flow discharges floodplain exposure and reworking by nw winds this cold dry period is coeval with the disappearance of megafauna and associated neanderthal communities and the replacement of the middle palaeolithic industries by upper palaeolithic ones in this westernmost part of europe

statistical analysis of inertial gravity wave parameters in the lower stratosphere over northern china to determine the morphology of inertial gravity wave igw activity in the lower stratosphere 18 25 km over northern china and provide observational data constraints for igw parameterization in atmospheric circulation models the seasonal variation and longitudinal distribution of igw parameters were analyzed statistically using 4 years 2010 2013 of radiosonde data from 20 sites distributed throughout northern china 80 2 e 122 3 e the results are as follows 1 the seasonal variation in the monthly mean igw energy strong in winter and weak in summer is consistent with the results for other regions in the northern hemisphere however the energy shows a significant longitudinal increase from west to east in winter and the opposite pattern in summer which has rarely been reported 2 the monthly mean intrinsic frequency exhibits clear seasonal variation large in winter and small in summer the annual average ratio with the coriolis frequency is 2 47 while the degree of polarization exhibits the opposite seasonal variation with an annual average of 0 71 the monthly mean vertical and horizontal wavelengths are 2 5 and 481 3 km in northern china respectively 3 the annual mean magnitude of the intrinsic horizontal group speed 7 0 m s is much larger than that of the vertical group speed 0 08 m s and both have maxima in winter and minima in summer the frequency of occurrence of the westward propagated igw is larger than that of the eastward propagated igw year round and it is isotropic in the north south direction this phenomenon is related to the filtering effect of the tropospheric westerly jet the annual mean fraction of upward propagation is 75 9 with a minimum in winter 4 the momentum flux exhibits a similar temporal and spatial distribution to energy showing preferred propagation in the northwest direction 5 the correlation of the monthly mean total energy of the igw with the westerly jet and the dynamic instability were studied the results suggest that the westerly jet near the tropopause has a strong influence on the igws activity in the lower stratosphere in northern china and the height region of the westerly jet is a possible source region for igws the maxima regions of the occurrence rates of dynamic instability at the upper and lower edges of the westerly jet in winter are also the possible source region for igws

lithofacies variations within sandur deposits the role of runoff regime flow dynamics and sediment supply characteristics abstract the icelandic sandur plains have for long acted as classic sites for models of braided river behaviour and of associated lithofacies assemblages however many of the icelandic sandurs are subject to repeated catastrophic flood events or jokulhlaups which are likely to have played a significant role in sandur construction established lithofacies models based on the icelandic sandurs have failed to take account of the varying runoff regimes which characterise the different sandur environments in addition sediment inputs to sandur channel systems are highly variable fluctuating in response both to varying runoff patterns and to advance and retreat of the source glacier that affect sediment availability within the proglacial zone this paper describes the main lithofacies types and vertical profiles that characterize the sandurs of south iceland and demonstrates that they can largely be attributed to extreme runoff events with few deposits typical of braided river facies occurring within the sedimentary record a preliminary qualitative model is developed that allows interpretation and prediction of vertical lithofacies profiles derived from glacial outwash in terms of i the drainage mechanism which in turn controls the dominant runoff population ii sediment availability and iii the spatial variability in flow dynamics

new data on the chronology of the vale do forno sedimentary sequence lower tejo river terrace staircase and its relevance as a fluvial archive of the middle pleistocene in western iberia abstract the vale do forno archaeological sites alpiarca central portugal document the earliest human occupation in the lower tejo river well established in geomorphological and environmental terms within the middle pleistocene in a staircase of six fluvial terraces the palaeolithic sites were found on the t4 terrace 24 m above river bed which is made of a basal lower gravels unit lg and an overlying upper sands unit us geomorphological mapping coupled with lithostratigraphy sedimentology and luminescence dating quartz osl and k feldspar post irir 290 were used in this study the oldest artefacts found in the lg unit show crude bifacial forms that can be attributed to the acheulian in contrast the us unit has archaeological sites stratigraphically documenting successive phases of an evolved acheulian luminescence dating and correlation with the marine isotopic stages suggest that the lg unit has a probable age of ca 335 to 325 ka and the us unit an age of ca 325 to 155 ka this is in contrast to previous interpretations ascribing this terrace and lithic industries to the last interglacial and early phases of the last glacial the vf3 site milharos containing micoquian final acheulian industries with fine and elaborated bifaces found in a stratigraphic level located between the t4 terrace deposits and a colluvium associated with late pleistocene aeolian sands is younger than 155 ka but much older than 32 ka

characteristics of inertio gravity waves revealed in rawinsonde data observed in korea during 20 august to 5 september 2002 1 characteristics of inertio gravity waves igws observed at six operational rawinsonde stations in korea from 20 august to 5 september 2002 and their relationship with convective sources are investigated several types of convective systems including mesoscale convective complexes and typhoon rusa passed the korean peninsula during the observing period to categorize the observed waves with and without convective sources wet and dry periods are defined at each observing site using hourly precipitation and satellite data although waves with extremely large values of intrinsic frequency and vertical wavelength are observed mostly in wet periods the mean values of wave parameters for wet and dry periods are similar low frequency igws can originate far from and long before the observing sites implying that it is unreasonable to correlate convective sources and observed waves at the same location and time for better correlation of the observed waves and their sources a three dimensional ray tracing model is used a new wet case is defined on the basis of the occurrence of convection when and where a ray locates in mid to upper troposphere characteristics of the observed waves for new wet and dry cases differ significantly the intrinsic frequency is larger but the horizontal wavelength is much smaller for wet than dry cases sources for wet cases are mostly convective clouds located northeast and southeast of the observing sites below 5 km this is clearly distinguished from dry cases where sources are located mostly in the northwest above 15 km and southeast far from the observing sites below 5 km

southern hemisphere extratropical gravity wave sources and intermittency revealed by a middle atmosphere general circulation model abstractsouthern hemisphere extratropical gravity wave activity is examined using simulations from a free running middle atmosphere general circulation model called kanto that contains no gravity wave parameterizations the total absolute gravity wave momentum flux mf and its intermittency diagnosed by the gini coefficient are examined during january and july the mf and intermittency results calculated from the kanto model agree well with results from satellite limb and superpressure balloon observations the analysis of the kanto model simulations indicates the following results nonorographic gravity waves are generated in kanto in the frontal regions of extratropical depressions and around tropopause level jets regions with lower higher intermittency in the july midstratosphere become more less intermittent by the mesosphere as a result of lower level wave removal the gravity wave intermittency is low and nearly homogeneous throughout the sh middle atmosphere during january this indicates t

simultaneous upward and downward propagating inertia gravity waves in the mlt observed at andes lidar observatory based on the temperature and zonal and meridional winds observed with a na lidar at andes lidar observatory 30 3 s 70 7 w on the night of 20 21 july 2015 we report simultaneous upward and downward propagating inertia gravity waves igws in the mesosphere and lower stratosphere mlt the ground based periods of the upward and downward igws are about 5 4 h and 4 8 h respectively the horizontal and vertical wavelengths are about 935 km and 10 9 km for the 5 4 h igw and about 1248 km and 22 km for the 4 8 h igw respectively hodograph analyses indicate that the 5 4 h igw propagates in the direction of about 23 west of north while the 4 8 h igw travels northward with an azimuth of 20 clockwise from north these wave parameters are in the typical igw wavelength and period ranges nevertheless the downward propagating igws in the mlt are rarely reported in previous observations the ray tracing analysis suggests that the 5 4 h igw is likely to originate from the stratospheric jet adjustment over the antarctic while the 4 8 h igw source may be above the mlt because it is unlikely to propagate downward through a reflection in the realistic atmospheric wind field although both igws do not reach their amplitude thresholds of instability the richard number reveals that the dynamical and convective instabilities occur intermittently which indicates that the instability arising from the multiple perturbation superposition may have a significant influence on wave saturation and amplitude constraint in the mlt

radiosonde observations of equatorial atmosphere dynamics over indonesia 2 characteristics of gravity waves this paper discusses the characteristics of gravity waves in the equatorial region revealed by analyzing radiosonde measurements of wind velocity and temperature fluctuations at 0 35 km with a height resolution of 150 m made every 5 7 hours between february 27 and march 22 1990 in east java indonesia we conducted hodograph analysis to delineate vertical and horizontal propagation characteristics and found that most gravity waves were generated in the middle of the troposphere and that they propagated upward into the stratosphere the amplitudes of wind velocity and temperature fluctuations due to gravity waves were larger in the stratosphere than in the troposphere the direction of horizontal propagation of gravity waves was rather uniformly distributed in the troposphere but it became eastward in the lower stratosphere being opposite to that of the mean winds because of quasi biennial oscillation the vertical wavenumber spectra of wind velocity were described fairly well by a saturated model spectrum although their amplitudes were smaller in the stratosphere a typical vertical wavelength was 2 2 5 km while the horizontal phase velocities were 5 7 and 12 m s in the troposphere and stratosphere respectively the amplitudes of small scale gravity waves were significantly larger in the equatorial stratosphere than at middle latitudes time height variation of the wind velocity variance due to gravity waves showed a clear correlation with that for high relative humidity which implies that cloud convection is an important mechanism of gravity wave generation in the equatorial region

characteristics of inertia gravity waves over the south pacific as revealed by radiosonde observations 1 using horizontal wind and temperature data with fine vertical resolution obtained by radiosondes we investigate the characteristics of parameters and propagation properties of inertia gravity waves in the upper troposphere and lower stratosphere in the subtropics and extratropics over the south pacific where very few observations have so far been done components extracted by a band pass filter having cutoff vertical wavelengths of 0 5 and 5 km are analyzed as gravity waves gravity wave parameters such as intrinsic frequency vertical and horizontal wavelengths and phase and group velocities are estimated by hodograph analysis the statistics on such parameters are presented for both the stratosphere and troposphere for the three latitudinal ranges 17 24 s 25 33 s and 34 48 s the horizontal wavelengths decrease and increases with increasing latitude south the dominant values for the coriolis parameter f divided by are 0 5 in the lower stratosphere and 0 3 in the troposphere with little dependence on latitude the dominant vertical wavelengths for upward propagating waves are longer in the troposphere than in the lower stratosphere the most dominant direction of horizontal propagation is southward with a little bias toward southeastward a case study using ray tracing suggests that the major source of such southeastward waves is located in the upper troposphere notable northward propagation of gravity waves is also found in the subtropical lower stratosphere the source of the gravity waves is considered to be a cutoff cyclone developing in the upper troposphere

radiosonde observations of equatorial atmosphere dynamics over indonesia 1 equatorial waves and diurnal tides this paper describes the characteristics of the mean winds equatorial waves with periods ranging from 4 to 20 days and diurnal tides determined by analyzing the profiles of wind velocity temperature and humidity obtained every 5 7 hours in the height range up to about 35 km with a height resolution of 150 m during an observation campaign conducted february 27 to march 22 1990 in east java indonesia the structures of the mean winds in the troposphere and lower stratosphere seemed to be affected by the australian monsoon and the quasi biennial oscillation respectively frequency spectra indicated that the equatorial waves as well as the diurnal tides were dominant below about 25 km while gravity waves with periods shorter than 4 days became more significant above 25 km a 7 day oscillation showing an antiphase relation between the eastward and northward components and exhibiting large amplitudes was observed in the lower troposphere the time height variations of the activity of this 7 day oscillation were clearly correlated with a region of high relative humidity perturbations in the zonal wind and temperature with wave periods varying from 15 to 17 days were also enhanced in the troposphere while kelvin waves with periods of about 7 and 20 days were detected in the lower stratosphere and activity near the tropopause was conspicuously enhanced we found that the 20 day kelvin wave greatly modified the structure of the tropopause such as the minimum temperature the tropopause height and the values of the brunt vaisala frequency squared n2 which further suggests the effects of kelvin waves on the transportation of tropospheric water vapor into the stratosphere and on the downward mixing of stratospheric minor constituents into the troposphere the observed profiles of the diurnal oscillation were compared with those of a numerical model assuming only migrating tides which reasonably agreed above about 25 km below 25 km however the observed amplitudes were 1 1 5 m s exceeding those of the model about 10 times moreover the phase profiles involved fluctuations with small vertical scales suggesting interference by many nonmigrating tides with short vertical wavelengths

subglacial meltwater channels and glaciofluvial deposits in the kimberley basin western australia 1 8 ga low latitude glaciation coeval with continental assembly a late palaeoproterozoic unconformity surface developed on low dipping sandstone in the kimberley region northwestern australia exhibits numerous linear parallel grooves 10 50 mm deep 40 80 mm wide and tens of metres long and other erosional forms including sichelwannen these features are interpreted as nye channels and sculpted forms eroded by subglacial meltwaters sandstone filled cracks exposed at the unconformity are viewed as periglacial frost fissures an overlying conglomerate facies 1 15 m thick at the base of the c 1800 ma king leopold sandstone kimberley basin succession contains poorly sorted pebble to boulder conglomerate and is interpreted as glaciofluvial in origin the orientation of the nye channels and sculpted forms and the palaeocurrent direction for the glaciofluvial deposits indicate westward ice flow the conformably following locally glauconitic quartzarenite of the king leopold sandstone probably accumulated in an epeiric sea implying that glaciation reached close to sea level transgression in northwestern and central australia at c 1800 ma may have been partly glacio eustatic glaciation was initiated to the east of the kimberley basin evidently in the halls creek orogen during a major phase of continental collision in australia and worldwide supercontinental assembly recognition of the king leopold glaciation which occurred in low palaeolatitudes c 2200 and 800 ma

dynamics of the equatorial mesosphere observed using the jicamarca mst radar during june and august 1987 abstract the jicamarca mst radar was used in two campaigns during june and august 1987 to measure wave influences flow variability and mean structure in the equatorial stratosphere and mesosphere this paper presents observations of motions and momentum fluxes in the mesosphere during each campaign a companion paper by hitchman et al addresses the mean structure and fluxes as well as comparisons with other datasets results presented here indicate that the equatorial mesosphere is dynamically very active with considerable gravity wave and tidal motions and persuasive evidence of inertial instability and wave filtering processes vertical velocities at high frequencies are comparable to those observed at other locations hourly mean horizontal motions and momentum fluxes are likewise large and variable exhibiting enormous vertical shears and strong modulation of the wave spectrum and momentum fluxes at higher frequencies daily mean profiles reveal persistent structures with vertical scales of 6 10

the excitation of equatorial waves by deep convection in the ncar community climate model ccm3 the forcing of equatorial waves by convective heating in the national center for atmospheric research community climate model ccm3 is investigated and compared with the forcing deduced from observations of convective clouds the analysis is performed on two different simulations wherein convection is represented by the zhang mcfarlane and the hack parameterization schemes respectively spectra of equatorial waves excited by convective heating rossby kelvin and gravity waves are obtained by projecting the heating field onto hough modes the dynamical response to the heating is then calculated in terms of the vertical component of the eliassen palm flux fz focusing on waves that are able to propagate into the middle atmosphere the same analysis is repeated using observations of outgoing longwave radiation as a proxy for tropical convection comparison of ccm3 results with those derived from observations indicates that high frequency heating variability is underestimated in both ccm3 simulations despite the fact that time mean values of convective heating are well represented moreover the two convective parameterization schemes differ substantially from each other compared to observations fz is severely underestimated at most frequencies when ccm3 is run with the zhang mcfarlane scheme when the hack scheme is used fz at frequencies v 0 5 cycles per day is comparable to the observations but it is underestimated at higher frequencies misrepresentation of the variability of convective heating is likely to have important consequences for the dynamical simulation of the middle atmosphere and even the troposphere