global gravity wave variances from aura mls characteristics and interpretation abstract the gravity wave gw resolving capabilities of 118 ghz saturated thermal radiances acquired throughout the stratosphere by the microwave limb sounder mls on the aura satellite are investigated and initial results presented because the saturated optically thick radiances resolve gw perturbations from a given altitude at different horizontal locations variances are evaluated at 12 pressure altitudes between 21 and 51 km using the 40 saturated radiances found at the bottom of each limb scan forward modeling simulations show that these variances are controlled mostly by gws with vertical wavelengths z 5 km and horizontal along track wavelengths of y 100 200 km the tilted cigar shaped three dimensional weighting functions yield highly selective responses to gws of high intrinsic frequency that propagate toward the instrument the latter property is used to infer the net meridional component of gw propagation by differencing the variances acquired from ascending a and descending d o

nonlinear horizontal diffusion for gcms abstract the mixing length based parameterization of horizontal diffusion which was originally proposed by smagorinsky is revisited the complete tendencies of horizontal momentum diffusion the associated frictional heating and horizontal diffusion of sensible heat in spherical geometry are derived the formulations are modified for the terrain following vertical hybrid coordinate system in a way that ensures energy and angular momentum conservation at each layer test simulations with a simple general circulation model run at t42 horizontal resolution and for permanent january conditions confirm the conservation properties and highlight the enhancement of nonlinear horizontal diffusion in areas of high baroclinic activity the simulated internal variability is dependent on the nature of the horizontal diffusion with high frequency variability being enhanced over the northern continents and low frequency variability being increased decreased over the pacific atlantic ocean when using nonlinear

mesoscale spectra of mars s atmosphere derived from mgs tes infrared radiances wavenumber spectra of the atmospheric potential energy of mars at mesoscales wavelengths of 64 957 km were obtained as a function of latitude season and martian year using infrared radiance data obtained by the thermal emission spectrometer tes onboard the mars global surveyor mgs spacecraft spectral slopes tend to be flatter at smaller scales and the slopes are usually flatter than 1 near small scale ends near large scale ends the spectra sometimes show prominent steepening with slopes from 2t o3 the power peaks in the high latitudes in winter and equinoxes suggesting that eddies are generated preferentially in baroclinic zones the seasonal variation at each latitude band on the other hand tends to be obscured by large interannual variability an enhancement in the power was observed around the storm tracks in the southern hemisphere spectra of the terrestrial stratosphere were also obtained with a similar method from data taken by the aura satellite and compared to the results for mars

the horizontal kinetic energy spectrum and spectral budget simulated by a high resolution troposphere stratosphere mesosphere gcm abstract horizontal kinetic energy spectra simulated by high resolution versions of the geophysical fluid dynamics laboratory skyhi middle atmosphere general circulation model are examined the model versions considered resolve heights between the ground and 80 km and the horizontal grid spacing of the highest resolution version is about 35 km tropospheric kinetic energy spectra show the familiar 3 power law dependence on horizontal wavenumber for wavelengths between about 5000 and 500 km and have a slope of 5 3 at smaller wavelengths qualitatively similar behavior is seen in the stratosphere and mesosphere but the wavelength marking the transition to the shallow regime increases with height taking a value of 2000 km in the stratosphere and 4000 km in the mesosphere the global spectral kinetic energy budget for various height ranges is computed as a function of total horizontal wavenumber contributions to the kinetic energy tendency from nonlinear advective processes from conversion of avai

observations of high frequency temporal gravity wave spectra in the middle upper stratosphere there is a paucity of high frequency temporal gravity wave spectra in the middle upper stratosphere 30 40 km as most instruments that are capable of accessing this region do not have the capability to make measurements for any extended period of time the spectral analysis of density fluctuations obtained with the purple crow rayleigh scatter lidar has shown that middle upper stratospheric temporal spectra follow the expected 1 5 to 2 0 power law relationship for frequencies less than 1 10 3 s 1 at frequencies greater than 1 10 3 s 1 the shape of the temporal spectrum is much more variable with strong quasi monochromatic features appearing intermittently on certain nights these higher frequency features have been attributed to nonlinear wave interactions and suggest that estimates of gravity wave activity in the middle upper stratosphere may be larger and much more variable than previously assumed this variability also suggests that middle upper stratospheric energy dissipation and eddy diffusion values may be much larger and more variable than previously assumed current parameterizations of subgrid dynamical processes in general circulation models that resolve this region may need to be reexamined in this light

frictional heating in global climate models abstract a new finite difference formulation of the frictional heating associated with atmospheric vertical momentum diffusion is proposed it is derived from the requirement that according to the no slip condition the sum of internal and kinetic energy of a fluid column is not changed by surface friction the present form is designed to be implemented along with the hybrid coordinate differencing scheme of simmons and burridge the effects of incorporating frictional heating in general circulation models gcms of the atmosphere are assessed by analyzing representative long term january simulations performed with an idealized gcm the model employs the proposed discretization of vertical terms as well as recently derived horizontal diffusion and dissipation forms for the conventional definition of a gcm with no frictional heating the climatological global energy budget yields a spurious thermal forcing of about 2 w m 2 in the equivalent new model definition this shortcoming is reduced by two orders

the effect of horizontal resolution on gravity waves simulated by the gfdl skyhi general circulation model to examine the effects of horizontal resolution on internal gravity waves simulated by the 40 level gfdl skyhi general circulation model a comparison is made between the 3 and 1 resolution models during late december the stratospheric and mesospheric zonal flows in the winter and summer extratropical regions of the 1 model are much weaker and more realistic than the corresponding zonal flows of the 3 model the weaker flows are consistent with the stronger eliassen palm flux divergence epfd

sources of gravity waves in the lower stratosphere above south pole 1 five year 2001 2005 high resolution radiosonde data were processed to obtain the gravity wave gw variabilities in the lower stratosphere over south pole sp our results show that gw activities in the lowermost section 10 15 km are strongest in may and september and weakest in the austral summer whereas in the altitude range of 15 25 km strongest weakest gw kinetic energy is observed around september january we also explored the relationships of gws to the synoptic scale variations in the troposphere and the ageostrophic motions in the upper troposphere over the antarctic which are expected to be significant mechanisms for gw generation a ray tracing model grograt was used to explore the relationship between gw propagation and the background field in the altitude of 15 25 km the annual cycle of gw activity resembles that of adjustment process below 15 km the annual cycle of gw activity has two peaks in may and september our analysis suggests that these two peaks are due to the variation of topographic gw generation and filtering of background atmosphere due to critical level filtering in the lowermost section topographic gws cannot propagate upward which makes the shape of gw annual cycle at higher altitudes closer to the annual cycle of adjustment processes the analysis suggests that the minimum of gw activity at sp during the austral summer may be due to the combination of weaker wave generation from adjustment processes associated with synoptic scale systems flow over topography and unfavorable background field for gw propagation

syn sedimentary gravity slides growth faults in the coal measures of south wales growth faults are an important class of syn sedimentary fault which have been widely recognized in sub surface studies of hydrocarbon bearing clastic basin successions1 4 they are listric normal faults which are active for a limited period during sediment deposition and therefore affect a discrete sedimentary interval whilst active the faults substantially influence sedimentation and a thicker generally sand dominated succession accumulates on the downthrown side which is consistently towards the basin the faults are not directly related to basement tectonics and instead are thought to originate principally by gravity sliding within the sediment pile5 over pressured undercompacted conditions in buried muds aid development of the faults by reducing the slope required to initiate sliding5 and in some cases associated mud diapirism also contributes by creating steeper slopes6 despite their widespread recognition in sub surface studies relatively few examples have been described from exposed successions7 10 and none from the economically important upper carboniferous coal measures of europe here we describe examples of growth faults recently discovered in an opencast site of the coal measures in south wales and comment on their possible significance

quasigeostrophic turbulence with explicit surface dynamics application to the atmospheric energy spectrum abstract the horizontal wavenumber spectra of wind and temperature near the tropopause have a steep 3 slope at synoptic scales and a shallower 5 3 slope at mesoscales with a transition between the two regimes at a wavelength of about 450 km here it is demonstrated that a quasigeostrophic model driven by baroclinic instability exhibits such a transition near its upper boundary analogous to the tropopause when surface temperature advection at that boundary is properly resolved and forced to accurately represent surface advection at the upper and lower boundaries the vertical structure of the model streamfunction is decomposed into four parts representing the interior flow with the first two neutral modes and each surface with its green s function solution resulting in a system with four prognostic equations mean temperature gradients are applied at each surface and a mean potential vorticity gradient consisting both of and vertical shear is applied in the interior the system exhibits three f

foreland basin structural growth recorded in the turonian ferron sandstone of the western interior seaway basin usa tectonic forcing of stratigraphic architecture is likely in foreland basins tectonic driving forces are increasingly being invoked to explain stratigraphic patterns in the cretaceous western interior seaway basin of north america yet the evidence is largely circumstantial and the details of driving forces remain elusive in this paper i show direct stratigraphic evidence for syndepositional growth of a structural arch with at least 50 m of relief during accumulation of the upper turonian ferron sandstone in south central utah united states progressive growth of the arch was superimposed on several high frequency stratal cycles that were driven by a more regionally extensive process geodynamic or eustatic and that produced laterally amalgamated sandstone bodies in a depositional strike parallel orientation north south all of this stratigraphy was then truncated by a more or less planar erosion surface sequence boundary that can be traced physically over at least 67 km north south this surface was later tilted northward such that the upper member of the ferron sandstone thins progressively southward from 50 to 10 m over 67 km the facies juxtapositions revealed by the ferron sandstone could if seen in exposure of limited lateral extent be wrongly interpreted as recording regionally extensive relative sea level drops and potentially used in error as evidence for substantial eustatic sea level falls during the turonian the folding and tilting documented in this study can be clearly attributed to geodynamic and or tectonic driving forces likely related to migration of a forebulge

the influence of gravity waves on the slope of the kinetic energy spectrum in simulations of idealized midlatitude cyclones abstractthe influence of gravity waves generated by surface stress and by topography on the atmospheric kinetic energy ke spectrum is examined using idealized simulations of a cyclone growing in

shallow water wave turbulence the dynamics of irrotational shallow water wave turbulence forced at large scales and dissipated at small scales is investigated first we derive the shallow water analogue of the four fifths law of kolmogorov turbulence for a third order structure function involving velocity and displacement increments using this relation and assuming that the flow is dominated by shocks we develop a simple model predicting that the shock amplitude scales as no matter how small shocks will prevail if the reynolds number is sufficiently large

mesoscale spectrum of atmospheric motions investigated in a very fine resolution global general circulation model 1 the horizontal spectrum of wind variance conventionally referred to as the kinetic energy spectrum is examined in experiments conducted with the atmospheric gcm for the earth simulator afes global spectral general circulation model we find that the control version of afes run at t639 horizontal spectral resolution simulates a kinetic energy spectrum that compares well at large scales with global observational reanalyses and at smaller scales with available aircraft observations at near tropopause levels specifically there is a roughly 3 power law dependence on horizontal wave number for wavelengths between about 5000 and 500 km transitioning to a shallower mesoscale regime at smaller wavelengths this is seen for both one dimensional spectra and for the two dimensional total wave number spectrum based on a spherical harmonic analysis the simulated spectrum at midtropospheric levels is similar in that there is a transition to a shallower mesoscale regime but the spectrum in the mesoscale is clearly steeper at midtroposphere than near the tropopause there seem to be no extensive observations of horizontal spectra available in the midtroposphere so it is not known whether the contrast seen in the model between upper and mid tropospheric levels is realistic the dependence of the model simulated variability on the subgrid scale moist convection parameterization is examined the space time variability of rainfall is shown to depend strongly on the convection scheme employed the tropospheric kinetic energy spectrum in the mesoscale seems to be correlated with the precipitation behavior so that in a version with a more variable precipitation field the kinetic energy in the mesoscale is enhanced this suggests that the mesoscale motions in the model may be directly forced to a significant extent by the variability in the latent heating field experiments were also performed with a dry dynamical core version of the model run at both t639 and t1279 resolutions this version also simulated a shallow mesoscale range supporting the view that the mesoscale regime in the atmosphere is energized at least in part by a predominantly forward i e downscale nonlinear spectral cascade experiments with various formulations of the hyperdiffusion horizontal mixing parameterization show that the kinetic energy spectrum over about the last half of the resolved wave number range is under strong control by the parameterized mixing however the t1279 model simulates almost a decade of the shallow mesoscale regime i e for horizontal wavelengths from about 80 to 500 km that appears to be fairly independent of the diffusion employed finally experiments are conducted in the dry version to see the effects on the kinetic energy spectrum of changing the thermal rossby number for the simulations

anatomy of falling stage deltas in the turonian ferron sandstone of the western henry mountains syncline utah growth faults slope failures and mass transport complexes falling stage deltas are predicted by sequence stratigraphic models yet few reliable criteria are available to diagnose falling stage deltaic systems in surface exposures recent work on the upper cretaceous turonian ferron sandstone in the western henry mountains syncline of south central utah has established its environment of deposition as a series of modest sized 5 to 20 km wide probably asymmetrical mixed influence deltas ferron notom delta that dispersed sediment eastwards from the rising sevier orogenic hinterland into the western cordilleran foreland basin analysis of sandstone body stacking patterns in a 67 km long depositional strike parallel north south transect indicates that the growth of successive deltas was strongly forced by synsedimentary growth of a long wavelength ca 100 km 50 m amplitude fold structure herein two discrete areas within this transect superbly exposed in three dimensions are documented in order to determine the details of stratal stacking patterns in the depositional dip direction and thereby to assess the stratigraphic context of the ferron notom delta in the two study areas dip transects expose facies representing river mouth bar to distal delta front environments over distances of 2 to 4 km key stratal packages are clinothems that offlap downlap and describe descending regressive trajectories with respective to basal and top datums they are interpreted as the product of relative sea level fall the vertical extent of clinoforms suggests that deltas prograded into 30 m of water furthermore these deltaic successions preserve abundant evidence of delta front slope failure growth faulting and incision and filling of deep 15 m slope gullies gully fills are composed of chaotic intraformational breccia and or massive sandstone and constitute linear shoestring sandbodies in the distal portions of individual palaeodelta systems they are interpreted to have been cut and filled during the late falling stage and lowstand of relative sea level cycles the north south distribution of the stratal style described above seems to be focused on the flanks of the growth anticline and so the numerous falling stage systems tracts preserved within the ferron notom delta probably owe their origin to synsedimentary structural growth and the unstable fluid pressure regime that this growth imposed on the sea floor and shallow subsurface

cross spectral analysis of the sst 10 m wind speed coupling resolved by satellite products and climate model simulations this study aims to determine the spatial temporal scales where the sst forcing of the near surface winds takes places and its relationship with the action of coherent ocean eddies here cross spectral statistics are used to examine the relationship between satellite based sst and 10 m wind speed w fields at scales between 10 2 10 4 km and 10 1 10 3 days it is shown that the transition from negative sst w correlations at large scales to positive at oceanic mesoscales occurs at wavelengths coinciding with the atmospheric first baroclinic rossby radius of deformation and that the dispersion of positively correlated signals resembles tropical instability waves near the equator and rossby waves in the extratropics transfer functions are used to estimate the sst driven w response in physical space w c a signal that explains 5 40 of the mesoscale w variance in the equatorial cold tongues and 2 15 at extratropical sst fronts the signature of ocean eddies is clearly visible in w c accounting for 20 60 of its variability in eddy rich regions to provide further insight on the role of ocean eddies in the sst driven coupling the analysis is repeated for two climate model ccsm simulations using ocean grid resolutions of 1 circ eddy parameterized lr and 0 1 circ eddy resolving hr the lack of resolved eddies in lr leads to a significantly underestimated mesoscale w variance relative to hr conversely the w c variability in hr can exceed the satellite estimates by a factor of two at extratropical sst fronts and underestimate it by a factor of almost six near the equator reflecting shortcomings of the ccsm to be addressed in its future developments

the horizontal spectrum of vertical velocities near the tropopause from global to gravity wave scales abstractvertical motions are fundamental for atmospheric dynamics compared to horizontal motions the horizontal spectrum of vertical velocity w is less well known here w spectra are related to

estimates of ocean macroturbulence structure function and spectral slope from argo profiling floats abstractthe argo profiling float network has repeatedly sampled much of the world ocean this study uses argo temperature and salinity data to form the tracer structure function of ocean variability at the macroscale 10 1000 km mesoscale and above here second order temperature and salinity structure functions over horizontal separations are calculated along either pressure or potential density surfaces which allows analysis of both active and passive tracer structure functions using argo data a map of global variance is created from the climatological average and each datum when turbulence is homogeneous the structure function slope from argo can be related to the wavenumber spectrum slope in ocean temperature or salinity variability this first application of structure function techniques to argo data gives physically meaningful results based on bootstrapped confidence intervals showing geographical dependence of the structure functions with slopes near on average independent of depth

subgrid parameterizations of the eddy eddy eddy mean field eddy topographic mean field mean field and mean field topographic interactions in atmospheric models abstractparameterizations are developed for each of the subgrid turbulence interaction classes in fully three dimensional global atmospheric flows over topography typical of january and july clima

middle atmosphere simulated with high vertical and horizontal resolution versions of a gcm improvements in the cold pole bias and generation of a qbo like oscillation in the tropics abstract the large scale circulation in the geophysical fluid dynamics laboratory skyhi troposphere stratosphere mesosphere finite difference general circulation model is examined as a function of vertical and horizontal resolution the experiments examined include one with horizontal grid spacing of 35 km and another with 100 km horizontal grid spacing but very high vertical resolution 160 levels between the ground and about 85 km the simulation of the middle atmospheric zonal mean winds and temperatures in the extratropics is found to be very sensitive to horizontal resolution for example in the early southern hemisphere winter the south pole near 1 mb in the model is colder than observed but the bias is reduced with improved horizontal resolution from 70 c in a version with 300 km grid spacing to less than 10 c in the 35 km version the extratropical simulation is found to be only slightly affected by enhancements of the vertical resolution by contrast the tropical middle atmospheric s

a very high resolution general circulation model simulation of the global circulation in austral winter abstract this paper discusses a simulation obtained with the geophysical fluid dynamics laboratory skyhi troposphere stratosphere mesosphere general circulation model run at very high horizontal resolution 60 km grid spacing and without any parameterization of subgrid scale gravity wave drag the results are for a period around the austral winter solstice and the emphasis is on the simulated southern hemisphere sh winter circulation comparisons are made with results obtained from lower horizontal resolution versions of the same model the focus in this paper is on two particularly striking features of the high resolution simulation the extratropical surface winds and the winter polar middle atmospheric vortex in the extratropical sh the simulated surface westerlies and meridional surface pressure gradients in the high resolution model are considerably stronger than observed and are stronger than those simulated at lower horizontal resolution in the middle atmosphere the high resolution model

the use of structure functions and spectra from numerical model output to determine effective model resolution abstract the effective model resolution of three numerical weather prediction nwp models is determined from analyses of spatial structure functions and spatial spectra in this paper the effective resolution is defined as the dimensions of the rectangular spatial filter that describes the net effect of all of the nwp model s numerical filtering and smoothing effects these effects are determined by comparison of spatial statistics of the nwp model output with statistical climatologies derived from aircraft data for the upper troposphere and lower stratosphere the comparisons are based on both spatial structure functions and spatial spectra the structure function approach has fewer assumptions and fewer numerical artifacts accurate estimates of nwp effective model resolution require a robust climatology of the spatial statistics which are a function of latitude and location such as over mountainous regions an artifact in the climatology of the velocity statistics resulting from mountain waves is i

spatial and temporal variability of the chemistry of the shallow groundwater in the alluvial fan area of the luanhe river north china groundwater in the alluvial fan area of the luanhe river north china was monitored every 2 months for a year subsequently the temporal and spatial variability in the hydrochemical characteristics of the water was investigated using hierarchical cluster analysis hca and a trilinear piper diagram it is found that the spatial variability in the groundwater composition from different monitoring wells has obvious differences even if the distance between many of the wells is small also the difference in the ion concentration was found to be up to fivefold for the same monitored well research has indicated that the groundwater s chemical characteristics are mainly controlled by soil type the amount of precipitation the luanhe river the groundwater and human factors the thickness and continuous distribution of clay influences the velocity and ion exchange rate of the groundwater flow this results in the amount of total dissolved solids in the groundwater increasing from upstream to downstream in the flood season june july and august ion concentration gradually decreases as a result of the increased recharging of the groundwater due to precipitation classification using hca indicates that the samples can be clustered into different groups according to correlation coefficients also the chemical composition of the water from monitoring wells near the luanhe river is approximately consistent with that from the luanhe river this implies that the samples have some compositions resulted from the mixing of groundwater and river water the piper diagram indicates that ca2 mg2 and hco3 ions are the predominant ones present i e the type of groundwater is of the ca mg hco3 type

intercomparison of gravity waves in global convection permitting models abstractlarge uncertainties remain with respect to the representation of atmospheric gravity waves gws in general circulation models gcms with coarse grids insufficient parameterizations resul

river dominated shelf edge deltas delivery of sand across the shelf break in the absence of slope incision shelf edge deltas record the potential magnitude of sediment delivery from shallow water shelf into deep water slope and basin floor and if un incised represent the main increment of shelf margin growth into the basin for that period the three dimensional complexity of shelf edge delta systems and along strike variability at the shelf edge in particular remains understudied the permian triassic kookfontein formation of the tanqua karoo basin south africa offers extensive three dimensional exposure 100 km2 and therefore a unique opportunity to evaluate shelf edge strata from an outcrop perspective analysis of stratal geometry and facies distribution from 52 measured and correlated stratigraphic sections show the following i in outer shelf areas parasequences are characterized by undeformed river dominated storm wave influenced delta mouth bar sandstones interbedded with packages showing evidence of syn depositional deformation the amount and intensity of soft sediment deformation increases significantly towards the shelf edge where slump units and debris flows sourced from collapsed mouth bar packages transport material down slope ii on the upper slope mouth bar and delta front sandstones pinch out within 2 km of the shelf break and most slump and debris flow units pinch out within 4 km of the shelf break iii further down the slope parasequences consist of finer grained turbidites characterized by interbedded thin tabular siltstones and sandstones the results highlight that river dominated shelf edge deltas transport large volumes of sand to the upper slope even when major shelf edge incisions are absent in this case transport to the upper slope through slumping debris flows and un channellized low density turbidites is distributed evenly along strike

general circulation model simulation of the semiannual oscillation of the tropical middle atmosphere abstract a study has been made of the evolution of the zonal mean zonal wind and temperature in a multiyear integration of the 40 level 3 3 6 resolution skyhi general circulation model gcm that has been developed at gfdl in the tropical upper stratosphere the mean wind variation is dominated by a strong semiannual oscillation sao the peak sao amplitude in the model is almost 25 m s 1 and occurs near the 1 mb level the phase of the sao near the stratopause is such that maximum westerlies occur shortly after the equinoxes these features are in good agreement with the available observations in addition the meridional width of the stratopause sao in the gcm compares well with observations a diagnostic analysis of the zonal mean momentum balance near the tropical stratopause was performed using the detailed fields archived during the gcm integration it appears that the easterly accelerations in the model sao are provided by a combination of i divergence of the meridional component of the el