migrating and nonmigrating semidiurnal tides in the upper atmosphere excited by tropospheric latent heat release migrating and nonmigrating semidiurnal tides

climatology of mesopause region temperature zonal wind and meridional wind over fort collins colorado 41 n 105 w and comparison with model simulations 1 between may 2002 and april 2006 many continuous observations of mesopause region temperature and horizontal wind each lasting longer than 24 h termed full diurnal cycle observations were completed at the colorado state university na lidar facility in fort collins colorado 41 n 105 w the combined data set consists of 120 full diurnal cycle observations binned on a monthly basis with a minimum of 7 cycles in april and a maximum of 18 cycles in august each monthly data set was analyzed to deduce mean values and tidal period perturbations after removal of tidal signals monthly mean values are used for the study of seasonal variations in mesopause region temperature zonal and meridional winds the results are in qualitative agreement with our current understanding of mean temperature and wind structures in the midlatitude mesopause region with an observed summer mesopause of 167 k at 84 km summer peak eastward zonal wind of 48 m s at 94 km winter zonal wind reversal at 95 km and peak summer pole to winter pole meridional flow of 17 m s at 86 km the observed mean state in temperature zonal and meridional winds are compared with the predictions of three current general circulation models i e the whole atmosphere community climate model version 3 waccm3 with two different simulations of gravity wavefields the hamburg model of the neutral and ionized atmosphere hammonia and the 2003 simulation of the thermosphere ionosphere mesosphere electrodynamics general circulation model time gcm while general agreement is found between observation and model predictions there exist discrepancies between model prediction and observation as well as among predictions from different models specifically the predicted summer mesopause altitude is lower by 3 km 8 km 3 km and 1 km for waccm3 the two waccm runs hammonia and time gcm respectively and the corresponding temperatures are 169 k 170 k 158 k and 161 k the model predicted summer eastward zonal wind peaks to 71 m s at 102 km to 48 m s at 84 km to 75 m s at 93 km and to 29 m s at 94 km in the same order the altitude of the winter zonal wind reversal and seasonal asymmetry of the pole to pole meridional flow are also compared and the importance of full diurnal cycle observations for the determination of mean states is discussed

meteoric sphaerosiderite lines and their use for paleohydrology and paleoclimatology sphaerosiderite a morphologically distinct millimeter scale spherulitic siderite feco 3 forms predominantly in wetland soils and sediments and is common in the geologic record ancient sphaerosiderites are found in paleosol horizons within coal bearing stratigraphic intervals and like their modern counterparts are interpreted as having formed in water saturated environments here we report on sphaerosiderites from four different stratigraphic units each of which has highly variable 13 c and relatively stable 18 o compositions the unique isotopic trends are analogous to well documented meteoric calcite lines which we define here as meteoric sphaerosiderite lines meteoric sphaerosiderite lines provide a new means of constraining ground water 18 o and thus allow evaluation of paleohydrology and paleoclimate in humid

an estimate of the momentum deposition in the lower thermosphere by the observed diurnal tide abstract this paper reports a calculation of the acceleration of the zonal mean flow induced by dissipating tides in the equatorial lower thermosphere estimates of the gravest symmetric gravitational hough mode 1 1 of the migrating diurnal tide are obtained from monthly composites of global winds observed by the upper atmosphere research satellite high resolution doppler imager using the principles of classical tidal theory the tidal momentum flux divergence is computed for a series of monthly mean 1 1 fields from january 1992 to may 1993 the contribution to the mean flow by the leading mode of the migrating tide ranges between 5 and 20 easterly m s 1 day 1 in the equatorial lower thermosphere a semiannual variation is noted in the tidal amplitudes and the inferred tidal accelerations these variations are consistent with observed trends in the zonal mean flow of the lower thermosphere

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

remote sensing lower thermosphere wind profiles using non specular meteor echoes 1 this article describes a new method of measuring wind velocity profiles between 93 km and 110 km altitude by tracking non specular meteor echoes as neutral winds transport the plasma trails this requires a large vhf radar with interferometric capability able to point nearly perpendicular to the geomagnetic field a small data sample from the jicamarca radio observatory allows the measurement of horizontal wind speeds and directions with a range resolution of a few hundred meters these observations show speeds reaching 150 m s and sometimes changing by as much as 100 m s over a 6 km altitude range at the best times these measurements can be made with only a few minutes of data with some refinement of the data collection and analysis techniques this technique should produce high resolution images of lower thermospheric winds as they change in both altitude and time

a linkage among pangean tectonism cyclic alluviation climate change and biologic turnover in the late triassic the record from the chinle formation southwestern united states abstract high precision geochronology provides unprecedented insights into the depositional history of the upper triassic chinle formation of the colorado plateau as well as its paleoenvironmental and paleobiological records the chinle succession exposed in the petrified forest national park pefo and vicinity arizona includes two large scale alluvial composite sequences although each composite sequence fines upward the upper composite sequence is more dominated by coarser grained deposits petrographic analysis of sandstone lithic content indicates an upward decrease in the proportion of volcanic rock fragments in each composite sequence paleocurrent indicators in the lower composite sequence suggest a variable paleoflow direction whereas northward paleoflow dominated the upper composite sequence the change in paleoflow appears to coincide with a reorganization of alluvial depositional processes and associated source terranes and precedes a rapid acceleration in basin subsidence climate proxy records from paleosol geochemistry indicate a gradual shift from humid to dry conditions across the transition between the lower and upper composite sequences and the adamanian revueltian biotic turnover composite sequence depositional reorganization climatic shift and biologic turnover in turn appear to coincide with episodes of magmatism recorded in triassic granitoid plutons presently exposed in southern california taken collectively these observations suggest that the late triassic depositional climatic and ecologic history at pefo may be related to emergence of the incipient cordilleran magmatic arc along the convergent western margin of pangea a new u pb date for the lower part of the chinle formation suggests that most or all of the formation was deposited in the norian stage

on the signature of the quasi 3 day wave in the thermosphere during the january 2010 ursi world day campaign 1 ultra fast kelvin waves with periods of 3 5 days are important in the coupling of the lower atmosphere to the thermosphere and ionosphere here we focus on the observations and effects of a 3 day wave during january 2010 as this time period coincides with a stratospheric warming event a coordinated set of observations with incoherent scatter radars are available while there is no evidence that the occurrence of this 3 day wave is connected with this event these observations offer an unprecedented glimpse of the thermospheric conditions during this period including the first ever detection of a 3 day wave with an incoherent scatter radar using a combination of ground and space based observations we identify an eastward moving zonal wave number one 3 day equatorial wave that is comprised of a kelvin wave at the lowest latitudes and a rossby gravity wave at higher latitudes in the equatorial region the vertical wavelength is 40 km and the wave peaks in amplitude around 95 100 km altitude the wave observed here is only seen to propagate to around 105 km altitude evidence of an interaction between this wave and the diurnal tide is seen between 82 88 km the resultant 3 day periodicity in the diurnal tide is seen to propagate up to altitudes of 150 km this could have a significant impact on the ionosphere via modulation of the e region dynamo thus carrying the 3 day periodicity to higher altitudes

large winds and wind shears caused by the nonlinear interactions between gravity waves and tidal backgrounds in the mesosphere and lower thermosphere a two dimensional nonlinear numerical model was used to simulate large winds 100m s 1 and wind shears 40m s 1 km 1 in the mesosphere and lower thermosphere mlt that are caused by the interaction between gravity waves gws and migrating tidal background by varying the wavelengths of gws and the phases of diurnal and semidiurnal tides 64 numerical experiments were performed our numerical experiments indicate that both migrating diurnal and semidiurnal tides strongly modulate the occurrence of gw breaking and the resulted large winds and wind shears the simulated large winds and wind shears are in good agreement with those from the rocket sounding chemical release measurements moreover the occurrence of large wind shears highly depends on the phases of migrating tides in local time which is in agreement with the reported lidar observations the local time dependence of large wind shears is mainly attributed to the filtering and or hindering effects of diurnal and semidiurnal tidal winds on gws our simulation reveals that the nonlinear interactions between gws breaking and the migrating diurnal and semidiurnal tides may play an important role in driving the large winds and wind shears in the mlt region and their local time dependence

formation of siderite mg calcite iron sulphide concretions in intertidal marsh and sandflat sediments north norfolk england concretions cemented mainly by siderite mg calcite and iron monosulphide are common in late holocene marsh and sandflat sediments on parts of the north norfolk coast field experiments have shown that the concretions are actively forming in reduced sediments in which sulphate reducing bacteria are active 13c values ranging from 3 to 11 8 mean 5 9 0 suggest that the carbonate in the concretions is derived partly from marine sources and partly from microbial degradation of organic matter 18o values ranged from 6 4 to 0 8 mean 1 0 suggesting that carbonate precipitated in porewaters ranging from pure sea water to sea water diluted with meteoric water chemical analysis of porewaters showed no evidence of significant sulphate depletion at the depth of concretion formation some concretions have formed around fragments of wood or metal but others contain no apparent nucleus in field experiments siderite fes and mg calcite were precipitated around several different nuclei within a period of six months we suggest that siderite may form wherever the rate of iron reduction exceeds the rate of sulphate reduction such that insufficient dissolved sulphide is available to precipitate all the available dissolved ferrous iron

diurnal nonmigrating tides from timed doppler interferometer wind data monthly climatologies and seasonal variations 1 timed doppler interferometer tidi measurements of zonal and meridional winds in the mesosphere lower thermosphere are analyzed for diurnal nonmigrating tides june 2002 to june 2005 climatologies of monthly mean amplitudes and phases for seven tidal components are presented at altitudes between 85 and 105 km and latitudes between 45 s and 45 n westward propagating wave numbers 2 3 and 4 the standing diurnal tide and eastward propagating wave numbers 1 2 and 3 the observed seasonal variations agree well with 1991 1994 uars results at 95 km comparisons between the tidi results and global scale wave model gswm and thermosphere ionosphere mesosphere electrodynamics general circulation model time gcm tidal predictions indicate that the large eastward propagating wave number 3 amplitude is driven by tropical tropospheric latent heat release alone in contrast latent heating and planetary wave migrating tidal interactions are equally important to westward 2 and standing diurnal tidal forcing there is good quantitative agreement between tidi and the model predictions during equinox but the latter tend to underestimate the westward 2 and standing diurnal tide during solstice neither model reproduces the observed seasonal variations of the eastward propagating components

could bacteria have formed the precambrian banded iron formations banded iron formations bifs are prominent sedimentary deposits of the precambrian but despite a century of endeavor the mechanisms of their deposition are still unresolved interactions between microorganisms and dissolved ferrous iron in the ancient oceans offer one plausible means of mineral precipitation in which bacteria directly generate ferric iron either by chemolithoautotrophic iron oxidation or by photoferrotrophy on the basis of chemical analyses from bif units of the 2 5 ga hamersley group western australia we show here that even during periods of maximum iron precipitation most if not all of the iron in bifs could be precipitated by iron oxidizing bacteria in cell densities considerably less than those found in modern fe rich aqueous environments those ancient microorganisms would also have been easily supported by the concentrations of nutrients p and trace metals v mn co zn and mo found within the same iron rich bands these calculations highlight the potential importance of early microbial activity on ancient metal cycling

large wind shears and stabilities in the mesopause region observed by na wind temperature lidar at midlatitude 1 unexpected large horizontal winds and wind shears in the lower thermosphere have been observed by rocket soundings and lidars for decades from 4 years of the colorado state university sodium wind temperature lidar data set 2002 2005 total of 1600 nocturnal h we observed an altitude distribution of high wind velocity and wind shears between 80 and 105 km similar to the results of chemical release experiments our lidar data show conclusively that when the observed wind shears are plotted as a function of the squared brunt vaisala frequency n2 they are below the value corresponding to the richardson number of 1 4 which is a necessary condition of the onset of dynamic instability this suggests that large wind shears can be sustained in the region of high static stability for example in the lower thermosphere where large wind shears are often observed by rocket sounding the full diurnal cycle lidar data enable the extraction of tidal wave components with periods of 24 12 8 and 6 h therefore allowing us to reveal the strong correlation of 60 between large wind shears 50 m s 1 km 1 and tidal waves the lidar measured seasonal variation in n2 and tidal amplitudes in the mesosphere and lower thermosphere are found to be consistent with the difference in altitude distribution of strong wind shears between winter and summer

rinded iron oxide concretions hallmarks of altered siderite masses of both early and late diagenetic origin iron bearing concretions are valuable records of oxidation states of subsurface waters but the first concretions to form can be altered drastically during later diagenetic events distinctive concretions composed of heavy rinds of iron oxide that surround iron poor mud rich cores are common along bases of fluvial cross bed sets of the cretaceous dakota formation nebraska usa concretion rinds thicken inward and cores contain 46 to 89 void space millimetre scale spherosiderites are abundant in palaeosols that developed in floodplain facies evolution of rinded concretions began when intraformational clasts were eroded from sideritic soils transported abraded and deposited in river channels alteration of siderite and formation of rinds occurred much later perhaps in the quaternary when sandstone pore waters became oxic dakota concretions are analogous to rattlestones in pleistocene fluvial channels of the netherlands and their rinded structure is analogous to that of iron rich concretions in the aeolian navajo sandstone of utah in all three deposits rinded concretions formed when pre existing siderite cemented concretions were oxidized within a sand matrix unlike fluvial examples siderite in the navajo sandstone was autochthonous and of late diagenetic origin having precipitated from carbon dioxide and methane enriched waters moving through folded and jointed strata iron rich rinds formed in all these strata because concretion interiors remained anaerobic even as oxygen accumulated in the pore waters of their surrounding permeable matrix iron oxide first precipitated at redox boundaries at concretion perimeters and formed an inward thickening rind acid generated by the oxidation reaction drove siderite dissolution to completion creating the iron poor core iron oxide rinds are indicators of the former presence of siderite a mineral that forms only under reducing conditions during either early or late diagenesis siderite is vulnerable to complete oxidation upon exposure so the distinctive rinded concretions are valuable clues that aid in deciphering diagenetic histories and for recognizing methanic floodplain palaeoenvironments and wet palaeoclimate

evolution of the holocene mississippi river floodplain ferriday louisiana insights on the origin of fine grained floodplains abstract the alluvial architecture and soil characteristics of holo cene mississippi river floodplain deposits in the southern lower mississippi valley provide evidence for significant changes in floodplain development in response to sea level rise floodplain cores acquired near ferriday louisiana show that holocene deposits consist of 15 30 m ave 20 m of sands silts and clays which overlie late wisconsin sands and gravels on the basis of differences in sediment grain size sediment body geometry and the abundance of soil features the holocene deposits are subdivided into lower and upper holocene units lower holocene deposits 5000 yr b p consist of lacustrine and poorly drained backswamp muds that contain authigenic siderite pyrite and vivianite and show little evidence of soil formation muds encase crevasse splay and floodplain channel sand bodies 1 km wide and collectively these deposits represent a mosaic of shallow lakes poorly drained backswamps and multichannel streams similar to modern examples in the atchafalaya basin 100 km south of ferriday upper holocene deposits 5000 yr b p are represented by large mississippi river meander belt sand bodies that are up to 15 km wide and 30 m thick natural levee silts and sands and well drained backswamp muds are present between meander belt sands upper holocene deposits contain abundant soil features and sandy and silty soils are entisols inceptisols and alfisols whereas clayey soils are vertisols the presence of isolated sand bodies surrounded by mud and the scarcity of soil features suggest that lower holocene sediments reflect a period of rapid floodplain aggradation during which crevassing lacustrine sedimentation and avulsion dominated floodplain construction no evidence of large meandering mississippi river channels represented by buried thick tabular sands exists near ferriday and discharge in lower mississippi valley flow was probably conveyed by a network of small multichannel floodplain streams upper holocene sediments record a dramatic change ca 5000 yr b p from rapid to slower floodplain aggradation which was accompanied by extensive lateral channel migration overbank deposition and soil formation on the basis of differences in meander belt dimensions and numbers of abandoned channels upper holocene meander belts are subdivided into simple and complex forms relative age relationships suggest that the smaller and older simple meander belts represent periods of divided mississippi river flow and early attempts to establish a large single channel meandering regime this type of meandering regime is represented by the larger and younger complex meander belts and includes the modern meander belt similarities in the timing of changes in floodplain processes and fluvial style and decreasing rates of holocene sediment accumulation in the southern lower mississippi valley strongly suggest that decelerating holocene sea level rise in the gulf of mexico affected floodplain development at least 300 km inland from the present day coast the alluvial architecture of the lower holocene deposits and the absence of large meandering mississippi river channel deposits older than 5000 yr b p near ferriday indicates that most of the floodplain muds were deposited by avulsion related crevassing and lacustrine sedimentation rather than by overbank flooding of large mississippi river channels similarities between the floodplain history of the mississippi river and those of modern and ancient rivers elsewhere further suggest that avulsion rather than simple overbank deposition contributes to the construction of fine grained floodplains to a greater degree than generally recognized

climatology of the migrating terdiurnal tide tw3 in saber timed temperatures 1 the present paper is focused on the global spatial altitude and latitude structure and seasonal and interannual temporal variability of the migrating terdiurnal tide tw3 seen in 8 years 2002 2009 of observations of the kinetic temperature measured by the saber instrument on the timed satellite the tides migrating and nonmigrating and the planetary waves zonally traveling and stationary are simultaneously extracted from the satellite data it is found that the saber tw3 tide is dominated by different hough modes below and above 80 to 90 km height in the mesosphere it reflects mainly the evanescent feature of the first symmetric mode and in the lower thermosphere propagating modes with shorter vertical wavelengths dominate its structure the seasonal behavior of the terdiurnal tide at low latitudes is dominated by an annual variation with local summer amplification while that at midlatitudes is a combination of semiannual variation with maxima in equinoxes and an annual variability with winter enhancement the hough modes of the solar heating from waccm heating to a large extent determine the predominantly antisymmetric features of the saber tw3 tide during the solstice but are not able to explain well the predominant symmetric features in the equinoxes the tw3 tide reveals some interannual variability with a period of quasi 2 years which indicates an enhancement during the eastward phase of the stratospheric qbo

mesospheric momentum flux studies at adelaide australia observations and a gravity wave tidal interaction model abstract we present here the results of an analysis of gravity wave momentum fluxes in the mesosphere and lower thermosphere inferred using a dual beam doppler radar near adelaide australia during june 1984 our analysis reveals that over 70 of the momentum flux and of the inferred zonal drag was due to gravity waves with observed periods less than one hour this suggests that it is the gravity waves with high intrinsic frequencies and small horizontal scales that are most effective at transporting momentum into the middle atmosphere the temporal variations in the momentum flux and flux divergence due to high frequency motions were also examined in detail in addition to daily variability a strong diurnal modulation was observed to occur this was found to be correlated with the phase of large amplitude diurnal tidal motions as a result of these observations a gravity wave tidal interaction model was proposed which accounts for all of the major features of the observed data including a reduction i

seismic interpretation of upper elk point givetian carbonate reservoirs of western canada1 the seismic signatures of three reefs of the upper elk point subgroup givetian stage of the western canada sedimentary basin are documented and analysed on the basis of variations in seismic image of particular lithologic units lateral amplitude and or phase changes structural relief and velocity generated relief as rendered by the reflection data the effects on seismic signatures of spatial geological variations resulting from such phenomena as differential compaction reef focused salt dissolution palaeotopography lateral and vertical facies variations regional dip and reservoir morphology are discussed the usefulness of seismic data in clarifying relationships between reefs and their adjacent sedimentary sections particularly in cases where well control is sparse is also considered such documentation of seismic signatures from known reefs using geophysical and geological analysis can establish criteria to enable recognition of similar buildups elsewhere three example reefs are presented each typical of a particular area and environment of w canada the first is from the winnipegosis formation of se saskatchewan the second and third from the rainbow member and upper keg river reef member respectively of the keg river formation of nw alberta all three of these carbonate buildups developed in the evaporitic elk point basin however the degree of salt encasement and subsequent dissolution varied greatly as do the resulting seismic effects for these three reef types the typical elements of their seismic signatures have been compiled and are here summarized

longitudinal variation of the e region electric fields caused by atmospheric tides 1 polarization electric fields created by the e and f region dynamos cause the uplift of f region plasma the subsequent redistribution of that plasma along the magnetic field lines creates the equatorial ionospheric anomaly eia observations of the post sunset eia made by the image and timed satellites are compared here with champ orsted and sac c observations of the noontime equatorial electrojet eej during magnetically quiet periods around equinox the eia and eej show a remarkably similar four peaked wave like longitudinal variation its structure is consistent with the longitudinal variation in the strength of diurnal tides that drive the e region dynamo this indicates a strong vertical coupling between the ionosphere and troposphere because the four peaked tidal structure is driven by tropospheric weather furthermore the dayside ionospheric conditions are found to perform the global scale longitudinal structure of the post sunset ionosphere at low latitudes

nonmigrating diurnal tides in mesospheric and lower thermospheric winds and temperatures abstract this paper presents analyses of nonmigrating diurnal tide signatures in high resolution doppler imager mesospheric and lower thermospheric winds and temperatures a global comparison of both winds and temperature reveals equatorial features corresponding to nonmigrating tides structures interpreted as zonal mean and eastward nonmigrating diurnal tides display consistency between horizontal winds and temperatures the second symmetric mode is prominent in the zonal mean and wavenumber 1 the gravest antisymmetric mode and the gravest symmetric or kelvin mode are the main features in zonal wavenumbers 2 and 3 the amplitudes of the tides generally increase with altitude and maximize within 90 110 km

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

intraseasonal and interannual variability of the quasi 2 day wave in the northern hemisphere summer mesosphere this study uses global synoptic meteorological fields from a high altitude data assimilation system to investigate the quasi 2 day wave q2dw and migrating diurnal tide during the northern hemisphere nh summers of 2007 2009 by applying a two dimensional fast fourier transform to meridional wind and temperature fields we identify q2dw source regions and diagnose propagation of q2dw activity into the upper mesosphere and lower thermosphere we find that the q2dw in nh summer is composed primarily of westward propagating zonal wave number 3 and wave number 4 components that originate within baroclinically unstable regions along the equatorward flank of the summer midlatitude easterly jet the amplitude of the wave number 3 q2dw tends to peak in july while the amplitude of the wave number 4 q2dw tends to peak in late june and again in early august the seasonal mean q2dw amplitudes are largest in 2009 when the amplitude of the migrating diurnal tide in the upper mesosphere near 30 n was relatively weak however there is no evidence of rapid amplification of the q2dw via nonlinear interaction with the diurnal tide instead variations of q2dw amplitudes during nh summer appear to be linked to variations in the strength and location of the mesospheric easterly jet from one summer to the next with a stronger jet producing larger q2dw amplitudes linear instability model calculations based on the assimilated wind fields indicate that the fastest growing modes are zonal wave numbers 3 and 4 with periods near 2 days that originate in the vicinity of the easterly jet

biosignatures link microorganisms to iron mineralization in a paleoaquifer concretions preferentially cemented masses within sediments and sedimentary rocks are records of sediment diagenesis and tracers of pore water chemistry for over a century rinded spheroidal structures that exhibit an fe iii oxide rich exterior and fe poor core have been described as oxidation products of fe ii carbonate concretions however mechanisms governing fe iii oxide precipitation within these structures remain an enigma here we present chemical and morphological evidence of microbial biosignatures in association with fe iii oxides in the fe iii oxide rich rind of spheroidal concretions collected from the jurassic navajo sandstone southwest united states implicating a microbial role in fe biomineralization the amount of total organic carbon in the exterior fe iii oxides exceeded measured values in the friable interior the mean 13 c value of organic carbon from the fe iii oxide cemented exterior 13 c of 20 55 is consistent with a biogenic signature from autotrophic bacteria scanning electron micrographs reveal microstructures consistent with bacterial size and morphology including a twisted stalk morphotype that resembled an fe ii oxidizing microorganism gallionella sp nanoscale associations of fe o c and n with bacterial morphotypes demonstrate microorganisms associated with fe iii oxides together these results indicate that autotrophic microorganisms were present during fe iii oxide precipitation and present microbial catalysis as a mechanism of fe iii oxide concretion formation microbial biosignatures in rinded fe iii oxide rich concretions within an exhumed quaternary aquifer has broad implications for detection of life within the geological record on earth as well as other fe rich rocky planets such as mars where both fe ii carbonate and fe iii oxide rich concretions have been identified

an empirical model of the earth s horizontal wind fields hwm07 1 the new horizontal wind model hwm07 provides a statistical representation of the horizontal wind fields of the earth s atmosphere from the ground to the exosphere 0 500 km it represents over 50 years of satellite rocket and ground based wind measurements via a compact fortran 90 subroutine the computer model is a function of geographic location altitude day of the year solar local time and geomagnetic activity it includes representations of the zonal mean circulation stationary planetary waves migrating tides and the seasonal modulation thereof hwm07 is composed of two components a quiet time component for the background state described in this paper and a geomagnetic storm time component dwm07 described in a companion paper

morphologic clues to the origins of iron oxide cemented spheroids boxworks and pipelike concretions navajo sandstone of south central utah u s a abstractconcretions cemented by iron oxide are abundant and diverse in the jurassic navajo sandstone of southern utah some of these structures are considered terrestrial analogs for concretions imaged on mars the navajo concretions can be spheroidal pipelike or tabular with multicompartmented boxworks these iron oxide concretions typically display a rinded structure dense sandstone rinds cemented by iron oxide surround pale iron poor sandstone cores within a single structure the iron rich rinds may be single or multiple pseudomorphs of siderite are present in local residual iron rich cores of boxworks workers in the late nineteenth through mid twentieth centuries many of whom found evidence for siderite precusors concluded that many spherical rinded iron oxide cemented concretions were formed by centripetal precipitation of iron oxide inward from the perimeter of the concretion in contrast the walls of pipelike concretions of iron oxide grew centrifugally outward we interpret the navajo

intense winds and shears in the equatorial lower thermosphere measured by high resolution nonspecular meteor radar large horizontal winds and wind shears have been measured in the lower thermosphere by rockets lidars and nonspecular meteor radars this paper describes a detailed analysis of three multihour nonspecular meteor radar data sets collected at the jicamarca radio observatory this provides some of the highest resolution sustained measurements in this part of the atmosphere these show 1 intense wind speeds maintaining 180 m s for half an hour and 160 m s for another half an hour 2 winds structured in layers that move up or more commonly down in the predawn hours at rates of a few kilometers per hour 3 intense wind shears that typically persist at around 50 m s km but in one instance sustains values approaching 100 m s km for a few hours

global distribution and interannual variations of mesospheric and lower thermospheric neutral wind diurnal tide 1 migrating tide 1 using the timed doppler interferometer tidi mesospheric and lower thermospheric neutral wind multiyear data set 2002 2007 and ncar time general circulation models gcm 1 2 annual run results 2002 2005 at the tidi sampling points we study the migrating diurnal tide s global distribution interannual and seasonal variations in connection with the mean zonal wind interannual variations a strong quasi biennial oscillation qbo effect on the diurnal tide was observed in the tidi data and reproduced to a lesser degree in the time gcm run the migrating diurnal tide amplitude is larger during the eastward phase of the stratospheric qbo and weaker during the westward phase westward mesospheric equatorial mean zonal winds appeared during the eastward phase of the stratospheric qbo in 2002 2004 and 2006 the strongest qbo effect on both the migrating diurnal tide and mean zonal winds was observed during the march equinox the stronger tides may be related to the weaker gravity wave filtering in the stratosphere during the eastward phase stratospheric qbo the tidi data also exhibit large interhemispheric asymmetry the westward mean zonal winds in the mesosphere appeared to be associated with the enhanced diurnal tide the time gcm 1 2 diurnal tide amplitudes are in general smaller than those observed by the tidi instrument limited vertical spatial resolution for the time cgm 1 2 is suggested as the cause future improvements are expected with a higher spatial resolution in the model

comparative study of short term diurnal tidal variability examination of the simultaneous temperature measurement from the sounding of the atmosphere using broadband emission radiometry saber instrument on board the thermosphere ionosphere mesosphere energetics and dynamics timed satellite not only confirms the existence of the inversion layer but also reveals the global nature of the inversion suggesting the presence of a transient planetary wave in the mesosphere the large tidal variability therefore is probably a consequence of the interaction between the transient planetary wave and tides this possibility is investigated by using the ncar thermosphere ionosphere mesosphere electrodynamics general circulation model time gcm and by comparing model results with the lidar saber and timed doppler interferometer tidi measurements with a large transient planetary wave specified at the model lower boundary the model is able to produce strong diurnal tidal variability comparable to that from the lidar observation and the modeled temperature inversion is similar to that from the saber measurement the model results suggest that the planetary tidal wave interaction excites nonmigrating tides and modulates the gravity modes and or the rotational modes of the diurnal migrating tide among the nonmigrating tides the diurnal zonally symmetric s 0 component is the strongest and its interaction with the planetary wave leads to a strong diurnal eastward wave number 1 component

nonmigrating semidiurnal tide over the arctic determined from timed doppler interferometer wind observations received 25 june 2009 revised 30 october 2009 accepted 5 november 2009 published 30 march 2010 1 the timed doppler interferometer tidi on the nasa thermosphere ionosphere mesosphere energetics and dynamics timed satellite has been measuring horizontal winds in the mesosphere and lower thermosphere mlt since 2002 because of the high inclination of the timed orbit tidi measures the horizontal winds from pole to pole every orbit this paper presents the first assessment of the spatial structure and temporal evolution of the nonmigrating semidiurnal tides over the arctic determined from the tidi wind measurements and a comparison of the structure of the nonmigrating semidiurnal tide between the arctic and antarctic the nonmigrating semidiurnal tides were determined as a 60 day average based on the yaw cycles of the spacecraft the nonmigrating semidiurnal tidal wind field over the arctic comprises mainly the westward propagating zonal wave numbers1 w1 and3 w3 andstandingzonalwavenumber0 s0 modes thew1modeis the most prominent maximizing above 90 km poleward of 60 n during the yaw interval ranging from mid march to mid may while this mode exhibits a slight amplitude increase toward the north pole during this interval its phase is nearly constant with latitude the s0 mode is enhanced over two yaw intervals ranging from mid january to mid may but its amplitude decreases toward the north pole compared to the w1 semidiurnal tide over the antarctic that over the arctic is smaller in amplitude of less extended duration achieves maximum amplitudes at higher altitudes by 10 km and exhibits a weaker amplitude increase toward the pole these differences likely result from differences in excitation mechanisms and efficiency and or in propagation conditions in the two responses for the nonmigrating semidiurnal tides between the arctic and antarctic

characteristics of instabilities in the mesopause region over maui hawaii 1 characteristics of convective and dynamical instabilities in the mesopause region between 85 and 100 km over maui hawaii 20 7 n 156 3 w are investigated using 19 nights 133 hours of high resolution wind and temperature data obtained by the university of illinois na wind temperature lidar during the maui mesosphere and lower thermosphere maui malt campaigns the mean probabilities of convective and dynamical instabilities are observed to be 3 and 10 respectively but there is considerable night to night variation at any given time the probability that an unstable condition is found at some altitudes in the 85 100 km range is 90 the maui malt data exhibit a distinct trend for n2 to increase with wind shear and vice versa this correlation has important implications in the understanding of the development of instabilities the night of 11 april 2002 is studied in detail in order to investigate the spatial and temporal structures of n2 wind shear and convective and dynamical instabilities a close linkage between instability and the mesosphere inversion layers mils is identified most of the convectively and dynamically unstable regions are located above the mils with a tendency for dynamical instability to develop below convective instability it is found that the vertical variations of n2 are often correlated with those of wind shear but with a phase shift such that the maxima and minima of n2 are located 0 5 1 km below those of wind shear because of this shift dynamical instability tends to develop in the region above the maximum wind shear where relatively small n2 is observed to be associated with large wind shear we also found that the wind shear is dominated by the contribution of the meridional wind especially when the wind shear is strong possible mechanisms for the observed features are discussed

observations of a nonmigrating component of the semidiurnal tide over antarctica 1 data obtained from the mf radars situated at davis syowa and rothera in antarctica are used to detect a nonmigrating component of the semidiurnal tide in the mesosphere and lower thermosphere these radars are at similar latitudes and so share a common migrating tidal component by fitting semidiurnal tide vectors to each stations data and performing subtractions of these vectors for pairs of stations the migrating component can be removed and the difference between the nonmigrating components revealed non zero differences in the summer months december to march indicate the presence of a significant nonmigrating component modeling studies and observations at other sites suggest that it is most likely the westward propagating wavenumber 1 nonmigrating component that is contributing to the semidiurnal tide the data presented here are found to be consistent with this hypothesis a climatology of this nonmigrating component is presented and discussed comparisons with the global scale wave model suggest that latent heat release is not a significant forcing mechanism at these heights and latitudes

a new geochemical classification of sedimentary environments because of the relative constancy of ph in most subaqueous sediments and the general lack of measurability of eh these parameters are not practically useful for classifying sedimentary environments in their place a new classification is offered which derived from studies of modern sediments is based on the presence or absence of dissolved oxygen and dissolved sulfide in the sediments at the time of authigenic mineral formation sedimentary environments are first of all divided into oxic and anoxic depending upon the presence or absence of measurable dissolved oxygen anoxic environments in turn are divided into sulfidic and non sulfidic depending upon the presence of measurable dissolved sulfide anoxic nonsulfidic environments are further divided into postoxic or resulting from oxygen removal without sulfate reduction weakly reducing and methanic or resulting from complete sulfate reduction with consequent methane formation strongly reducing the environments are shown to succeed one another during early diagenesis in the order oxic post oxic sulfidic methanic iron and manganese minerals characteristic and stable in each environment are listed and discussed so that they may be used to distinguish the environments when studying the ancient geological record

concurrent oh imager and sodium temperature wind lidar observation of localized ripples over northern colorado 1 on 3 and 5 september 2002 the oh all sky imager at platteville colorado 40 2 n 104 7 w observed small scale wavelike patterns known as ripples with horizontal wavelengths of 9 km and 7 km and lifetimes of 9 min and 15 min respectively the colorado state university sodium lidar at nearby fort collins colorado 40 6 n 105 w also made concurrent observations of temperature and zonal and meridional winds which allowed us to determine the nature of the ripples observed our observations suggest that the 3 september ripple was induced by a convective instability located at 87 5 km and the 5 september ripple was induced by a dynamic instability at 88 5 km the ripples clearly advected as packets with the background wind lidar measurements also allowed us to relate the directions of wind shear to the phase front alignments of both the ripples and the nearby short period atmospheric gravity waves these spatial relationships provided a meaningful comparison with previously observed ripples as well as with current theoretical models using the 16 hour continuous lidar data set for each case we deduced that long period waves created an unusually large temperature perturbation at the ripple times on 3 september and an unusually large wind shear perturbation on 5 september these perturbations prepared the background atmosphere to be near the verge of local instability but as revealed again by lidar observation it was the superposition of smaller scale perturbations at the time of the ripples that helped to actually reach the conditions required for instability and generation of the ripples

nonmigrating semidiurnal and diurnal tides at 95 km based on wind measurements from the high resolution doppler imager on uars 1 for more than a decade derived results from the high resolution doppler imager hrdi on uars have provided an enormous amount of new and invaluable information on the global variability of atmospheric winds these and other results have given added impetus to theoretical modeling efforts until recent years the large majority of investigations have focused on migrating tides and now more results on nonmigrating tides have become available we provide new results for semidiurnal and diurnal nonmigrating tides based on data from hrdi at 95 km much of these results have not been obtained before and they are substantially different from those that have been previously reported our amplitudes are usually significantly larger with more periodicities in both day of year and latitude than results that have previously appeared in the literature we also find components up to longitude wave number 3 that are significant and have not been presented before and that traveling components of larger longitude wave numbers 4 5 and 6 can reach several m s in amplitude we compare our results with earlier results based on hrdi measurements and from selected models

global mesospheric tidal winds observed by the high resolution doppler imager on board the upper atmosphere research satellite this paper presents preliminary results of a study of mesospheric and lower thermosphedc diurnal tidal winds obtained with the high resolution doppler imager hi on the upper atmosphere research satellite uars zonal averages of the meddional and zonal wind fields are performed at fixed local times these analyses reveal tidal structures in the mean meridional wind field during the months of february and march 1992 results are presented for a typical day in february 1992 the observed maximum amplitude of meridional wind is approximately 75 m s 1 the observed vertical wavelength is about 20 km with amplitudes increasing linearly with height in addition to the tides the zonal wind field reveals many features of the mesospheric

estimation of the equivalent rayleigh friction in mesosphere lower thermosphere region from the migrating diurnal tides observed by timed 1 we use thermosphere ionosphere mesosphere energetics and dynamics timed global temperature and wind data from 2002 to 2007 to investigate the damping of the diurnal tide horizontal winds are measured by tidi and are calculated from saber temperature measurements the determination of tidal winds from saber temperature depends on the damping and therefore the discrepancy between tidi and saber determinations of the wind tides can be used to calculate the tidal damping this damping is approximated here by an equivalent rayleigh friction erf and it is adjusted to minimize the difference in winds derived from saber and tidi data the results show that during some periods the erf coefficient can be very large over narrow vertical regions of about 5 km 10 5 s 1 in low latitudes and about 10 4 s 1 in midlatitudes the magnitude and shape of the vertical profiles change with latitude and season the peak in the vertical profile of erf is larger and located at a higher altitude in summer than in winter and the erf coefficients at 40 are stronger than at 20 in both hemispheres the erf deduced in this study without a priori assumption about the mechanism of the damping shows a seasonal variation that is clearly consistent with the seasonal variation of the zonal mean wind the maximum erf generally coincides with the altitudes of strongest wind reversal in the mesopause region

southern argentina agile meteor radar system design and initial measurements of large scale winds and tides 1 the southern argentina agile meteor radar saamer was installed at rio grande on tierra del fuego 53 8 s 67 8 w in may 2008 and has been operational for 24 months this paper describes the motivations for the radar design and its placement at the southern tip of south america its operating modes and capabilities and observations of the mean winds planetary waves and tides during its first 20 months of operation saamer was specifically designed to provide very high resolution of large scale motions and hopefully enable direct measurements of the vertical momentum flux by gravity waves which have only been possible previously with dual or multiple beam radars and lidars or in situ measurements saamer was placed on tierra del fuego because it was a region devoid of similar measurements the latitude was anticipated to provide high sensitivity to an expected large semidiurnal tide and the region is now recognized to be a hot spot of small scale gravity wave activity extending from the troposphere into the mesosphere and lower thermosphere perhaps the most dynamically active location on earth saamer was also intended to permit simultaneous enhanced meteor studies including head echo and nonspecular measurements which were previously possible only with high power large aperture radars initial measurements have defined the mean circulation and structure exhibited planetary waves at various periods and revealed large semidiurnal tide amplitudes and variability with maximum amplitudes at higher altitudes often exceeding 60 m s 1 and amplitude modulations at periods from a few to 30 days

the geologic context of wonderstone a complex outcrop scaled pattern of iron oxide cement abstract although siderite is a widespread early diagenetic mineral in fluvial systems it is unstable in oxidizing environments and destroyed in permeable rocks that experience uplift and exhumation the products of siderite oxidation however mm to cm scale rhombs concretions and complex bands of iron oxide cement are widespread in the rock record of fluvial systems the fluvial channels of the shinarump member of the chinle formation in southern utah and northern arizona u s a provide an excellent suite of examples of diagenetic features produced by triassic and neogene oxidation of early diagenetic siderite these diagenetic features also provide direct evidence of the level of the water table during deposition of the shinarump member large in situ discoidal concretions containing preserved siderite are present in shinarump floodplain siltstones rip up clasts derived from the siltstones developed iron oxide rinds during late stage near surface oxidation these two structures show that floodplain silts contained abundant organic matter and methanic pore water groundwater recharging through these silts carried reducing water through underlying sand bodies and discharged into active channels degassing of co2 and methanogenesis caused rhombic crystals of siderite to precipitate in channel sands during these wet intervals some of this siderite may have been oxidized during dry intervals when groundwater circulation reversed but most siderite in the channel sands was preserved until the shinarump was exhumed during the neogene as oxygenated near surface water entered joints in the lithified shinarump colonies of iron oxidizing microbes living in the phreatic zone occupied redox boundaries and used the rhombic crystals of siderite in the sandstone and the spherulitic siderite in transported siltstone intraclasts as their sources of energy and carbon the ferrous iron released from dissolving siderite within the intraclasts was oxidized at the siltstone sandstone contact generating rinded concretions similar to those in the cretaceous dakota formation complex banding known as wonderstone was produced in the channel sandstones from oxidation of the rhombic siderite the pattern is a combination of liesegang bands and microbially mediated cements the preserved rhombs are pseudomorphs after siderite crystals that were either oxidized during triassic dry intervals or escaped neogene microbial oxidation in the phreatic zone only to be oxidized abiotically in the vadose zone microbes are likely oxidizing shinarump siderite a few kilometers down dip of outcrops with exposed wonderstone at such locations the shinarump is in contact with overlying water saturated quaternary alluvium

diurnal variation of gravity wave momentum flux and its forcing on the diurnal tide 1 the diurnal variation of gravity wave gw momentum flux is derived from the 5 years of meteor radar wind measurements at maui hawaii the amplitude and phase relationships between the gw forcing and the diurnal tide are analyzed by calculating their equivalent rayleigh frictions the results show that the gw momentum flux is clearly modulated by the diurnal tide the forcing from the momentum flux convergence has strong effects on both the amplitude and phase of the diurnal tide they can reach 80 ms 1 day 1 for the amplitude and 15 h day 1 for the phase the gw forcing tends to increase the diurnal tide amplitude above 90 km but has a small damping effect below 90 km it tends to increase the phase of the diurnal tide throughout all altitudes seasonal variations of the gw forcing exist which result in differences in their effects on the diurnal tide the magnitudes of the forcing are in agreement with recent results from satellite observations but are much larger than values used in general circulation models this work also demonstrates that meteor radar measurements can provide a valuable data set for the study of gw tide interactions

tidal perturbations and variability in the mesopause region over fort collins co 41n 105w continuous multi day temperature and wind lidar observations 1 an unusually long data set was acquired at the sodium lidar facility at colorado state university 41n 105w between sep 18 and oct 01 2003 including a 9 day continuous observation this time is long enough to average out the perturbations of gravity waves and short period planetary waves as such it can be used to define tidal period perturbations in temperature and horizontal wind assuming the sodium mixing ratio is a constant of motion the observed tidal period oscillation in sodium density follows that of vertical wind thus the data set defines tidal period perturbations of temperature and wind vector the observed amplitudes and phases were compared to global scale wave model predictions both gswm00 and gswm02 we found excellent agreement in diurnal phases and reasonable agreement in semidiurnal phases however gswm02 overestimates diurnal amplitudes and both model versions underestimate observed semidiurnal amplitudes since the data period is long enough for the study of planetary waves and of tidal variability we perform spectral analysis of the data revealing a strong quasi 3 day wave in meridional wind a 14 hour perturbation in zonal wind and both 14 hour and 10 hour periods in meridional wind likely the result of nonlinear interactions the observed semidiurnal amplitudes are much larger than the corresponding diurnal amplitudes above 85 km and over a few days the diurnal and semidiurnal amplitudes vary by factors of 2 3 causes for the observed tidal variability in terms of planetary wave modulation and tide gravity wave interaction are explored qualitatively

the meridional wind component of the thermospheric tide observed by windii on uars thermospheric meridional winds measured by the wind imaging interferometer windii on the upper atmosphere research satellite uars are analyzed for migrating solar tides for march april 1993 tidal signatures are extracted by zonally averaging and binning the data in equally spaced intervals of local time latitude and altitude an examination of the binned data reveals vertically propagating tides in the lower thermosphere with the diurnal tide dominating at low latitudes above 120 km evidence of vertical propagation ceases and the vertical gradients are significantly reduced in regions where both daytime and nighttime data are available fourier decomposition of the binned winds is used to extract the diurnal component of the tide this analysis reveals that the propagating diurnal tide attains a maximum amplitude of 65 m s at 20 n and 20 s at 95 km and exhibits a vertical wavelength of about 25 km

comparison of champ and time gcm nonmigrating tidal signals in the thermospheric zonal wind 1 four years 2002 2005 of continuous accelerometer measurements taken onboard the champ satellite orbit altitude 400 km offer a unique opportunity to investigate the thermospheric zonal wind on a global scale recently we were able to relate the longitudinal wave 4 structure in the zonal wind at equatorial latitudes to the influence of nonmigrating tides and in particular to the eastward propagating diurnal tide with zonal wave number 3 de3 the de3 tide is primarily excited by latent heat release in the tropical troposphere in deep convective clouds in order to investigate the mechanisms that couple the tidal signals to the upper thermosphere we undertook a comparison with the thermosphere ionosphere mesosphere electrodynamics general circulation model time gcm developed at the national center for atmospheric research ncar we ran the model for a day in march june september and december and applied the same processing steps to the model output as was done for the champ tidal analysis the main results of the comparison can be summarized as follows 1 time gcm simulations do not correctly reproduce the observed intra annual variations of de3 and the eastward propagating diurnal tide with zonal wave number 2 de2 2 simulations of de3 for june are more successful both time gcm and champ show an increase in de3 amplitudes with decreasing solar flux level 3 the amplitudes of the simulated westward propagating diurnal tide with zonal wave number 2 dw2 and the standing diurnal tide d0 increase with increasing solar flux in june the predicted dependence of dw2 and do on solar flux is also observed by champ

a seismic analysis of black creek and wabumun salt collapse features western canadian sedimentary basin two devonian salts of western canada those of the black creek member upper elk point subgroup in northwest alberta and those of the wabamun group in southeastern alberta were widely distributed and uniformly deposited within their respective basins both of these salts are interbedded within predominantly carbonate sequences and both have been extensively leached they are now preserved as discontinuous remnants of variable thickness and areal extent these salt remnants and their associated collapse features are often associated with structural or stratigraphic traps structural traps typically form where reservoir facies are closed across remnant salts stratigraphic traps often develop where reservoir facies were either preferentially deposited and or preserved in salt collapse lows as a result of these relationships between dissolution and hydrocarbon entrapment the distribution areal extent and thickness of these salt remnants is of significant interest to the explorationist both the black c

sources of nonmigrating tides in the tropical middle atmosphere 1 temperature measurements from the cryogenic infrared spectrometers and telescopes for the atmosphere crista experiment taken during the u s space shuttle mission sts 66 in november 1994 provide a variety of zonally symmetric and asymmetric tidal signatures in the altitude range from 40 90 km the most prominent zonally asymmetric tidal pattern is identified to be the westward propagating nonmigrating diurnal tide of zonal wavenumber 2 s 2 this mode has an amplitude of approximately half the amplitude of the migrating s 1 component of the diurnal tide the observational findings are compared to model results from the global scale wave model gswm and from the thermosphere ionosphere mesosphere electrodynamics general circulation model time gcm gswm and time gcm account for different tidal sources and therefore allow an analysis of the tidal forcing responsible for the observed signatures the gswm tidal forcing in the model version used is based upon latent heat release associated with tropical deep convection while nonmigrating tides in the time gcm are predominantly forced by nonlinear interactions between the migrating diurnal tide and stationary planetary waves it is shown that the latter mechanism forces a large part of the s 2 mode while the stationary zonally uniform s 0 diurnal nonmigrating tide is mainly driven by latent heat release this result suggests that dynamical models for the mesosphere lower thermosphere mlt region need to account for the tropospheric latent heat source and stationary planetary wave activity in order to predict realistic longitudinal diurnal tidal variability

global ionospheric response to nonmigrating de3 and de2 tides forced from below 1 in this paper we present the global spatial structure and seasonal variability of the cosmic electron density response to the forced from below de3 and de2 tides during the period january 2008 to march 2009 the cosmic electron density at fixed altitudes and saber temperatures were utilized in order to define the ionospheric de3 and de2 tidal response to the de3 and de2 temperature tides coming from below the tidal waves from both data sets have been extracted by the same data analysis method the latitude structure of the ionospheric response for heights up to 450 500 km is distributed on both sides of the dip equator at about 30 modified dip latitude above 500 km the response is approximately confined over the equator two altitude regions of enhanced ionospheric response are found an upper level response above 300 km and a bottom level one below 250 km the two regions are separated by a narrow altitude zone with no tidal response the different phase structure of the ionospheric response in both altitude regions suggests that 1 the upper level response is mainly due to the de3 de2 modulated vertical plasma drift and 2 the bottom level response is complex and in all likelihood is caused by more than one mechanism

large wind shears and their implications for diffusion in regions with enhanced static stability the mesopause and the tropopause the ncar whole atmosphere community climate model waccm with a quasi uniform horizontal resolution of 25km and a vertical resolution of 0 1 scale height produces large vertical shear of horizontal wind with peaks around the mesopause and the tropical and midlatitude tropopause in these regions the static stability also reaches peak values and therefore allows large vertical shears before the onset of dynamical instability the wind shear peaks near the mesopause and the tropopause from the simulation compare well with those identified in observations including the magnitude latitudinal dependence and large shear statistics by analyzing the probability density functions of the wind shears and their dependence on the zonal scales it is found that smaller scale processes likely gravity waves contribute significantly to the large shears and may play a dominant role in producing the largest shears climatological tidal waves have secondary contribution to the large winds and shears but spectral analysis suggests that they can modulate wind shear perturbations by gravity waves in the mesosphere and lower thermosphere implications for tracer transport and mixing in these regions are explored by estimating diffusion coefficients based on the root mean square winds shears and corresponding spatial scales from model results

atmospheric tide 2 the solar and lunar semidiurnal components solar and lunar semidiurnal wind and temperature oscillations from the surface to 400 km are simulated for average solar activity conditions utilizing the numerical tidal model described in part 1 hough mode decomposition of the solstitial solar semidiurnal tide excited by h2o and o3 insolation absorption below 80 km indicates that it is characterized by a predominance of 2 2 below 60 km about equal contributions of 2 2 2 3 and 2 4 between 70 and 90 km mostly 2 4 with some 2 5 and 2 2 between 90 and 120 km and a predominance of 2 2 above 140 km with secondary contributions from 2 3 and 2 5 the solstitial lunar semidiurnal tide is characterized by a predominance of 2 2 below 70 km 2 4 with secondary contributions from 2 2 2 3 and 2 5 between 80 and 110 km and by 2 2 with a fairly strong secondary contribution from 2 3 above 120 km similar descriptions for both the solar and lunar oscillations apply at equinox except that the asymmetric 2 3 and 2 5 modes are absent relative to the solar component lunar temperature and wind amplitudes are sufficiently large 20 in the lower and upper thermosphere to account for some of the observed variability previously attributed to the solar tide amplitudes of the 2 4 and 2 5 modes above 100 km are significantly affected by mesospheric eddy diffusion coefficients in excess of 2 106 cm s 1 the total solar semidiurnal exospheric temperature oscillation for average solar conditions ranges from 10 20 k poleward of 40 n to 40 60 k equatorward of 30 n and has its origin in three sources of excitation all of comparable importance 1 euv solar radiation absorption in the lower thermosphere 100 200 km 2 in situ momentum coupling due to the interaction of diurnal winds and diurnally varying ion drag and 3 tides propagating upwards from below 100 km in addition the calculations are compared with rocket meteor radar partial reflection thomson scatter and satellite data to evaluate the consistency of the model with observations

contemporaneous subsidence and fluvial channel sedimentation upper mannville c pool berry field lower cretaceous of alberta upper mannville c pool is a small oil pool which produces from lower cretaceous fluvial sandstones in berry field southeastern alberta ultimate oil reserves of the pool are 5 8 million m3 of oil contained within a sandstone body about 7 5 km long and 2 km wide the pool is unusual for its occurrence on the flank of a local structural high within a large regional structural depression sandstone distribution rather than present day structure dictates the occurrence of hydrocarbons yet the distribution of sandstones was controlled by structure a fluvial channel was diverted into an area of synsedimentary faulting or downwarping which then controlled the depositional form of an asymmetric wedge of channel levee and crevasse splay sands the most likely cause of subsidence was differential salt solution regionally the berry area lies along the margin of several devonian salt formations which are known to have undergone partial solution lateral migration of the locus of salt solution and hence subsidence through time produced both the facies and structural configurations observed in this oil pool

tidal wind mapping from observations of a meteor radar chain in december 2011 1 this article proposes a technique to map the tidal winds in the mesosphere and lower thermosphere mlt region from the observations of a four station meteor radar chain located at middle and low latitudes along the 120 e meridian in the northern hemisphere a 1 month dataset of the horizontal winds in the altitude range of 80 100 km is observed during december 2011 we first decompose the tidal winds into mean diurnal semidiurnal and terdiurnal components for each station it is found that the diurnal semidiurnal components dominate at the low latitude midlatitude stations their amplitudes increase at lower altitudes and then decrease at higher altitudes after reaching a peak in the mlt region hough functions of the classical tidal theory are then used to fit the latitudinal distribution of each decomposed component the diurnal component is found to be dominated by the first symmetric 1 1 mode yet for the semidiurnal and terdiurnal components the corresponding dominant modes are the second symmetric modes 2 4 and 3 5 and considerable contributions are also from the first antisymmetric modes 2 3 3 4 and second antisymmetric modes 2 5 3 6 based on the decomposed results we further map the horizontal winds in the domains of latitude altitude and local time the mapped horizontal winds successfully reproduce the local time versus altitudinal distributions of the original observations at the four stations thus we conclude that the meteor radar chain is useful to monitor and study the regional characteristics of the tidal winds in the mlt region

on the large wind shear and fast meridional transport above the mesopause 1 unexpectedly strong winds shears and fast meridional transport above the mesopause have been revealed from previous rocket and satellite observations using richardson number criteria for dynamic stability we estimate the maximum wind shears allowable by the background static stability which peaks above the mesopause these maximum shears are in general agreement with the large wind shears inferred from the rocket measurements at low and mid latitudes indicating the close relationship between the latter and the stability constraint set by the background atmosphere diagnostic calculations also indicate that the meridional transport in this region may not be well understood solely by examining the mean meridional circulation and large amplitude tides planetary waves can play an important role in the bulk transport of tracers strong stochastic winds presumably due to gravity waves do not seem to significantly change the large scale pattern of the transport but may extend the range of the tracer movement

multi proxy paleosol evidence for middle and late triassic climate trends in eastern utah abstract prior investigations suggest that alluvial lowlands of pangea in the southwestern u s a during the middle to late triassic experienced an arid to semiarid climate with significant seasonality our investigation finds evidence for a global pluvial episode from paleosols in the middle to late triassic section of eastern utah multi proxy paleosol evidence is used to quantify rainfall amounts ambient temperatures and atmospheric co 2 concentrations and infer associated plant formations related to ecosystem persistence rainfall estimates are derived from geochemical molecular weathering ratios temperature and atmospheric co 2 levels from stable oxygen and carbon isotopes of pedogenic carbonate respectively and ecosystem reconstruction by a combination of climate indexes and paleosol characteristics eight pedotypes were identified and include poorly drained aquic entisols fisher well drained non aquic entisols salt valley calcic aridisols castle valley calcic inceptisols moab cambic ute and calcic la sal vertisols dystric inceptisols kokopeli and argillic alfisols slickrock the middle triassic moenkopi formation anisian was dominated by castle valley paleosols with mean annual rainfall between 300 and 400 mm and mean annual temperature between 13 and 23 c mesic to hyperthermic based on these climate indexes and root traces the associated plant formation was most likely desert shrub or dry woodland the lower chinle formation carnian contains a succession of ute and la sal paleosols that changed up section to kokopeli fisher and slickrock paleosols in accordance with geochemical and isotopic signatures from these pedotypes rainfall amounts initially increased to between 700 and 900 mm and then to between 1300 and 1400 mm temperatures estimated from the la sal paleosol are approximately 18 c thermic at this time the lower chinle marks a transition from dry woodland to open forest that appears to correlate with the formation of the petrified forest member in arizona the upper chinle formation carnian norian reveals a return to semiarid to subhumid conditions and the formation of castle valley moab and salt valley paleosols all of which appear to have supported desert shrub or dry woodlands rainfall amounts decreased to between 400 and 600 mm with temperatures eventually increasing to 29 c hyperthermic using the paleosol isotopic barometer atmospheric co 2 estimates generally correlate with other proxy for the triassic the well developed alfisols and noncalcareous inceptisols identified during the carnian of the lower chinle correlate with a previously identified global pluvial episode based on sedimentological and marine isotopic evidence possibly in response to rifting of pangea it should not be assumed that the middle to late triassic in continental alluvial lowlands supported a uniform semiarid to arid climate with strong seasonality

ionospheric detection of the 25 may 2009 north korean underground nuclear test 1 the total electron content tec measurements of the global navigation satellite system gnss revealed traveling ionospheric disturbances tid that locate north korea s underground nuclear explosion une of 25 may 2009 to within about 3 5 km of its seismically determined epicenter the random chance for this pattern of tids to register across the eleven gnss stations is roughly 1 in 19 billion monte carlo analysis of nearly 1 300 tids from a 7 station subset of the 11 gnss stations supports the statistical strength of the array s signature the une was also detected by seismic stations and possibly a local infrasound network of the international monitoring system ims of the comprehensive nuclear test ban treaty organization ctbto but no radionuclide evidence was found thus global gnss infrastructure enables mapping spatial and temporal variations of tec that augment and complement other methods of detecting and locating clandestine unes

kinematic implications of joint zones and isolated joints in the navajo sandstone at zion national park utah evidence for cordilleran relaxation 1 at zion national park znp the landscape is a consequence of differential weathering of the navajo sandstone where closely spaced vertical joints constitute joint zones that erode to form regularly spaced half kilometer slot canyons striking 351 between these joint zones is a set of isolated joints striking 339 fracture interaction and horsetail wing crack development indicate that the 339 striking joint set is younger than the 351 striking joint zones despite the lateral extent of stress reduction shadows in the vicinity of the large scale joint zones in addition to an older less pervasive 020 joint set this sequence of jointing records a counterclockwise rotation of the regional extension directed from wnw to wsw in the navajo sandstone at znp znp is located at the western margin of the colorado plateau 100 km east of the major normal faults of the northeastern central basin and range subprovince extension within the eastern central basin and range initiated during the miocene and exhibited a wsw extension direction anderson 1971 wernicke et al 1988 snow and wernicke 2000 the correlation between nearby basin and range extension and the extension direction for the 351 tending joint zones of znp is so close that the jointing at znp is interpreted as evidence for modest yet pervasive basin and range extension in the western margin of the colorado plateau

satellite observations of thermospheric tides results from the wind imaging interferometer on uars thermospheric winds measured by the wind imaging interferometer windii on the upper atmosphere research satellite are analyzed for migrating solar tides the data cover a 2 year period commencing february 1992 and are obtained from the atomic oxygen o 1s 557 7 nm emission which provides observations of the 90 to 200 km altitude range during daytime and the 90 to 110 km range at night the subtropical lower thermosphere is dominated by the diurnal propagating tide which exhibits a vertical wavelength of approximately 22 km grows in amplitude up to 95 km and decays rapidly above where molecular diffusion greatly reduces the vertical shears although the phase remains fairly uniform throughout the year a pronounced semiannual oscillation is observed in the diurnal tide amplitude at both 20 n and 20 s the meridional and zonal wind components attain their maximum values at equinox of approximately 70 and 40 m s respectively while the solstitial minima are nearly a factor of 2 smaller at 35 n the diurnal tide semiannual amplitude oscillation is still present in the lower thermosphere but above 100 km it is replaced by an annual cycle with a maximum in july and august this contrasts with 35 s where the july august peak is absent and the semiannual oscillation extends to 110 km at midlatitudes the zonal and meridional winds are of similar magnitude and no significant hemispheric asymmetries in amplitudes are observed in the lower thermosphere the semidiurnal tide amplitude exhibits an annual oscillation with maximum values of 30 to 40 m s occurring in june july near 100 km at 35 n 35 s and the equator a bimodal structure in the seasonal variation of the semidiurnal phase is observed this feature is characterized by rapid equinoctial transitions and is particularly well defined at the equator examination of the equatorial middle thermosphere indicates that the semidiurnal tide attains its maximum amplitude at 140 km and exhibits a vertical wavelength of approximately 60 km these findings indicate the predominance of the antisymmetric 2 3 hough mode in the tropics

first results from the meteor radar at south pole a large 12 hour oscillation with zonal wavenumber one the first mesopause region ca 92 5 km wind measurements from the meteor radar at amundsen scott station at south pole are described measurements are made along four orthogonal azimuth directions approximately 2 from the geographic south pole a large 20 ms 1 oscillation in the northward wind is observed with 12 hour period and zonal wavenumber one a similar wave was observed during august 1 13 1992 at south pole by hernandez et al 1993 using optical methods the predominant semidiurnal tide in the atmosphere is migrating with the apparent motion of the sun with s 2 the s 1 oscillation is interpreted here to result from the nonlinear interaction between the migrating semidiurnal tide and a stationary wave with s 1 the present mechanism represents an alternative to the gravity wave driven pseudotide theory put forth by walterscheid et al 1986 to explain the occurrence of unexpectedly large semidiurnal tidal oscillations at high latitudes

diurnal migrating tide as seen by the high resolution doppler imager uars 1 monthly mean global meridional winds the high resolution doppler imager hrdi instrument on board the upper atmosphere research satellite measures global winds in the mesosphere and lower thermosphere on a day to day basis the horizontal coverage of the hrdi data is excellent and provides a unique opportunity to study global scale dynamic phenomena however the local time resolution and coverage are limited because of the nature of the satellite sampling the lack of local time coverage makes conventional methods of data analysis e g fourier analysis both difficult and erroneous an original method of analysis based on a numerical model of atmospheric thermal tides is proposed and applied to the hrdi data the tidal model is solved for the tidal oscillations in the meridional wind component the simulated diurnal meridional tidal winds are used as a first guess in the analysis the results of the model are adjusted to give meridional migrating tidal winds that have maximum consistency with hrdi measurements this technique is used to derive monthly mean tidal oscillations of the meridional velocity the derived tidal amplitudes show profound seasonal changes that seem to be consistent with gravity wave breaking theory the results are compared with mf radar data it is found that in the upper mesosphere and lower thermosphere the tidal amplitudes obtained by hrdi can be bigger than those from mf radars by a factor of 2

ground magnetic effects of the equatorial electrojet simulated by the tie gcm driven by timed satellite data quiet time daily variations of the geomagnetic field near the magnetic equator due to the equatorial electrojet are simulated using the national center for atmospheric research ncar thermosphere ionosphere electro dynamics general circulation model tie gcm and compared to those observed by ground based magnetometers simulations are run both with and without tidal forcing at the height of the model lower boundary 97 km when the lower boundary forcing is off the wind that generates an electro motive force in the model is primarily the vertically non propagating diurnal tide which is excited in the thermosphere due to daytime solar ultra violet heating the lower boundary tidal forcing adds the effect of upward propagating tides which are excited in the lower atmosphere and propagate vertically to the thermosphere the main objective of this study is to evaluate the relative importance of these thermospherically generated tides and upward propagating tides in the generation of the equatorial electrojet fairly good agreement is obtained between model and observations when the model is forced by realistic lower boundary tides based on temperature and wind measurements from the thermosphere ionosphere mesosphere energetics and dynamics timed satellite as determined by wu et al 2012 the simulation results show that the effect of upward propagating tides increases the range of the geomagnetic daily variation in the magnetic northward component at the magnetic equator approximately by 100 it is also shown that the well known semiannual change in the daily variation is mostly due to upward propagating tides especially the migrating semidiurnal tide these results indicate that upward propagating tides play a substantial role in producing the equatorial electrojet and its seasonal variability

follow the water connecting a co2 reservoir and bleached sandstone to iron rich concretions in the navajo sandstone of south central utah usa concretions with thick iron oxide cemented rinds and lightly cemented iron poor sandstone cores are abundant within the navajo sandstone near the southeast fl ank of the escalante anticline utah united states previous workers suggested the spheroidal concretions as analogs for martian blueberries hematite concretions and linked the origin of concretions and bleaching of the navajo sandstone to the buoyant rise of hydrocarbons toward anticlinal crests we measured azimuths of 163 pipe like pipy joint associated concretions and those of 58 comet tails that extend from some spherical concretions both data sets have vector magnitudes 90 and subparallel southeast directed resultant vectors our data indicate that groundwater transported and deposited iron over a fl ow path that spanned more than 100 km from the anticlinal crest to the colorado river buoyant fl uids could not have transported iron from bleached rock to sites of concretion growth however because iron moved downdip we propose that iron was transported southeastward by reducing groundwater that fl owed through a co 2 and methane charged reservoir within the escalante anticline iron rich carbonates precipitated during co 2 degassing after methane was fl ushed from the aquifer microaerophiles oxidized fe 2 in concretions dissolving the carbonates and forming the iron oxide rich rinds and iron poor cores these concretions defi ne the fl ow direction and geochemical evolution of a paleoaquifer this approach could be used to follow the water on other planets

seasonal variations of mlt tides revealed by a meteor radar chain based on hough mode decomposition seasonal variations of different tides in the mesosphere and lower thermosphere are investigated from wind observations of a meteor radar chain on the basis of hough mode decomposition first the observed winds are decomposed into different diurnal semidiurnal and terdiurnal tidal components different seasonal patterns are revealed for each component pronounced semiannual oscillation sao is presented in the diurnal component while latitude dependent seasonal variation is found in the semidiurnal and terdiurnal components at the low midlatitude stations the semiannual annual oscillation is relatively stronger then hough mode decomposition is utilized to extract the dominant tidal modes of each decomposed component it is found that each component is dominated by one of its symmetric tidal modes with strong seasonal dependency apparent sao is observed in the dominant 1 1 mode 2 4 mode is strong in the autumn and winter months after the september equinox based on the extracted results we further map the three dimensional distribution latitude altitude season of each tidal component the mapped results are finally compared with the corresponding values observed by the thermosphere ionosphere mesosphere energetics and dynamics doppler interferometer tidi and modeled from the global scale wave model gswm each mapped tidal component agrees well with corresponding tidi observation in the seasonal variation meanwhile coincidences are found in the seasonal dependency of the diurnal component between the mapped values and the modeled results from gswm while difference between them exists in that of the semidiurnal one

simulated equinoctial asymmetry of the ionospheric vertical plasma drifts 1 this paper studies the influence of the lower thermospheric tidal winds below 105 km on the equinoctial asymmetry of the equatorial vertical e b plasma drifts v using theoretical ionospheric dynamo model ii of the institute of geology and geophysics chinese academy of sciences tidm iggcas ii and tidal winds below 105 km from thermosphere ionosphere mesosphere energetics dynamics satellite doppler interferometer tidi observations although a series of other nonmigrating tides also affect the v asymmetry the simulated equinoctial asymmetry in v are mainly driven by the migrating diurnal tide dw1 migrating semidiurnal tide sw2 de3 and dw2 nonmigrating tides the asymmetry in daytime v varies with local time and longitude and mainly shows three features first the simulated daytime v during the march equinox is larger than that during the september equinox in most of longitudinal sectors this asymmetry is mainly driven by the semiannual oscillation sao of the migrating diurnal tide in the tropical mesosphere lower thermosphere mlt region and the equinoctial asymmetry of the migrating semidiurnal tide also plays an important role in the generation of this asymmetry second the daytime v asymmetry in the eastern hemisphere is more significant than that in the western hemisphere our simulation suggests that the longitudinal variations of the geomagnetic fields and dw2 tides play important roles in the generation of this hemisphere difference third there is an obvious wave number 4 longitudinal structure in the v asymmetry our simulation suggests that this wave number 4 structure is mainly driven by the equinoctial asymmetry of the de3 tide

longitudinal structure of the equatorial anomaly in the nighttime ionosphere observed by image fuv 1 the far ultraviolet imager fuv on board the image satellite provides an instantaneous global view of the oi 135 6 nm nightglow with 2 min time resolution because the oi 135 6 nm emission from the nighttime ionosphere is determined by the line of sight integrated plasma density the nightglow images are useful for studying the nighttime low latitude ionosphere globally with the image fuv 135 6 nm observations from march to june 2002 we have examined the global characteristics of the nighttime equatorial anomaly ea by constructing a constant local time map lt map in which pixels within an assigned local time range are extracted from the image fuv nightglow images obtained over an observation period of 3 days or more and are put together to compose a global distribution map of emission intensities at that local time these lt maps show that the development of the ea has a significant longitudinal structure in which peaks and dips of the crest emission intensity and the crest latitude have about 90 longitudinal separation in the longitude range from 0 to 250 although there is not enough data over the american sector this result suggests that the ea longitudinal structure has a prominent zonal component of the wave number 4 the observed longitudinal structure of the nighttime ea could not be fully explained by factors such as the empirical electric field and neutral wind models the geomagnetic declination angle or the displacement of the geomagnetic equator from the geographic equator to explain the observed longitudinal structure of the ea in particular the wave number 4 feature we may need to consider other forcing for example nonmigrating tide originated from the lower atmosphere

quantification of the gravity wave forcing of the migrating diurnal tide in a gravity wave resolving general circulation model 1 the interaction of gravity waves gws and the migrating diurnal tide are studied in a gw resolving general circulation model gcm by calculating the tidal components of zonal wind accelerations and equivalent rayleigh friction due to tidal induced gw dissipation two 15 day periods for perpetual equinoctial and solstice simulations are analyzed which are performed with the japanese atmospheric general circulation model for upper atmosphere research jaguar high resolution gcm the model can directly simulate gws with horizontal wavelengths greater than about 190 km and thus reproduce the general features of the mean winds and temperatures from the surface to the mesosphere and lower thermosphere mlt the amplitudes of the migrating diurnal tide are successfully simulated during both seasons and the tidal winds affect the altitudes of gw dissipation in the low latitude mlt the tidal component of gw forcing has maximal values of about 15 m s 1 d 1 near the maximal vertical shears of the tidal winds and generally works to shorten the vertical wavelength of the migrating diurnal tide the phase relationship between the tidal winds and the tidal induced gw forcing is not exactly 90 out of phase causing amplification suppression of the tide the gw forcing amplifies the migrating diurnal tide during the equinox while during the solstice it suppresses the tidal winds in the upper mesosphere of both hemispheres this difference in behavior can be attributed to a seasonal variation of the mean zonal winds because combination of the mean and tidal winds affects the altitudes of gw dissipation

interactions of a paleocene river a rising fold and early diagenetic concretions abstract the relative rates of sediment accumulation erosion and structural uplift determine whether a growing fold develops positive topographic relief is beveled by antecedent streams or is buried under thick growth strata when folds rise in subsiding basins upward convergent flow of groundwater through the permeable growth strata that underlie antecedent streams enhances the flux of ions required for concretion growth early diagenetic concretions that grow in such alluvial strata may constitute the only clasts larger than sand size available for transport when antecedent streams become erosive the first reworked concretions deposited by these streams should accurately mark the transition from aggradation to erosion as folds rise into the paths of streams in this situation the ability to differentiate reworked from in situ concretions is crucial the west vergent simpson ridge anticline a n s trending thick skinned laramide structure in east central wyoming separates the larger hanna basin from the carbon basin near the north nose of this anticline in situ iron oxide rich concretions are abundant in folded paleocene strata ferris formation and just to the east large reworked iron rich concretions are abundant in younger more gently dipping conglomerates in the basal hanna formation of the backlimb smaller reworked concretions are also present near the base of the hanna formation at least 7 km south of the anticlinal nose and just east of the fold9s axis at the anticlinal nose in situ non reworked concretions up to 3 m 1 m 1 m are abundant at the top of an 7 km thick sequence of sandstones and siltstones that constitute the late cretaceous early paleocene ferris formation reworked concretions are absent in the strata hosting these in situ concretions but reworked concretionary clasts up to 2 m in diameter are present in exposures of conglomerates in the lowermost hanna formation that lie just above the in situ ferris concretions and southeast of the anticlinal nose these early diagenetic concretions were originally cemented by siderite feco 3 oxidation of some small rinded siderite cemented clasts took place after their fluvial transport into the hanna formation but abundant angular un rinded iron oxide cemented clasts indicate that many large in situ siderite concretions had resided in the vadose zone before they were entrained the distribution of reworked concretions and the orientations of crossbeds show that antecedent hanna streams eroded a swath at least 5 km wide across the rising structure these streams transported ferris formation concretions southeastward into the carbon basin and deposited them in a conglomeratic sandstone body in the hanna formation large calcite cemented concretions many with a pipe like morphology then grew within hanna crossbeds in many cases these in situ concretions enclose transported iron rich concretions but there is no evidence any calcite cemented concretions were reworked the nw se alignment of the pipes record southeastward flow of groundwater and thus also provide evidence together with the orientation of the crossbeds of the original continuity of the hanna formation across the anticline reworked concretions reveal the interplay of deposition diagenesis and erosion due to convergent groundwater flow over growing anticlines early diagenetic concretions both in situ and as reworked clasts are especially likely to be found in growth strata

momentum budget of the migrating diurnal tide in the whole atmosphere community climate model at vernal equinox 1 the momentum budget of the migrating diurnal tide dw1 at the vernal equinox is studied using the whole atmosphere community climate model version 4 waccm4 classical tidal theory provides an appropriate first order prediction of the dw1 structure while gravity wave gw forcing and advection are the two most dominant terms in the momentum equation that account for the discrepancies between classical tidal theory and the calculation based on the full primitive equations it differs from the conclusion by mclandress 2002a that the parameterized gw effect is substantially weaker than advection terms based on the canadian middle atmosphere model cmam in the region where dw1 maintains a large amplitude gw forcing in the wave breaking region always damps dw1 and advances its phase the linear advection largely determined by the latitudinal shear of the zonal mean zonal wind makes a dominant contribution to the phase change of dw1 in the zonal wind compared to the gw forcing and nonlinear advection however nonlinear advection is more important than gw forcing and linear advection in modulating the amplitude and phase of dw1 in the meridional wind the dw1 amplitudes in temperature and winds are smaller than the timed observations suggesting that gw forcing is overestimated in the waccm4 and results in a large damping of dw1

atmospheric tides in the low latitude e and f regions and their responses to a sudden stratospheric warming event in january 2010 an extensive analysis of atmospheric tides in the low latitude thermosphere and their responses to a major sudden stratospheric warming ssw event 18 23 january 2010 is presented the analysis is based on observational data from the arecibo dual beam incoherent scatter radar important findings of the present study are as follows 1 the diurnal tide with an evanescent phase structure dominates the f region meridional wind field the diurnal tide has a peak amplitude of 45 m s occurring at about 245 km and it is very stable throughout the nine consecutive days observation below 114 km the vertical structures of the diurnal tide in the meridional and zonal components are consistent which resemble the classical solar s 1 s 1 tidal mode 2 the f region semidiurnal tide is much weaker and has larger day to day variability than the diurnal tide in the e region the semidiurnal amplitudes in the meridional and zonal components grow continuously in the altitude ranges from 106 to 121 km and from 100 to 115 km respectively the vertical wavelength of the zonal component is estimated to be 45 km above 100 km which is close to the solar s 2 s 4 and s 2 s 5 tidal modes 3 the semidiurnal and terdiurnal tides respond strongly to the ssw while the impact that the ssw has on the diurnal tide in the meridional wind is limited during the ssw event the amplitudes of the semidiurnal and terdiurnal tides are enhanced in the f region but reduced in the upper e region

global structure and seasonal and interannual variability of the migrating diurnal tide seen in the saber timed temperatures between 20 and 120 km 1 the present paper is focused on the global spatial altitude and latitude structure and seasonal and interannual variability of the migrating diurnal tide derived from the sounding of the atmosphere using broadband emission radiometry thermosphere ionosphere mesosphere energetics and dynamics saber timed temperature measurements for 6 full years january 2002 to december 2007 the tidal results are obtained by a new analysis method where the tides migrating and nonmigrating and the planetary waves zonally traveling and stationary are simultaneously extracted from the satellite data it has been found that above 70 km height the saber migrating diurnal tide reflects mainly the distinctive features of the first symmetric propagating 1 1 mode while below this height it reflects the features of the first symmetric trapped 1 2 mode the trapped component amplifies near 50 km and its phase is close to 1600 lt the seasonal behavior of the diurnal tide over the equator is dominated by semiannual variation with a primary maximum in february march 18 k average amplitude for 6 years and a secondary maximum in august september 15 k the tidal amplitude grows rapidly in the mesosphere lower thermosphere however it undergoes some decay near 90 km defining ubiquitous double peaked vertical structure a very rapid reduction in amplitude is detected at heights near 115 km however above this level the diurnal tide amplifies again the vertical wavelength of the propagating diurnal tide is 20 km over the equator at middle latitudes it is not very different from that over the equator but its magnitude depends on the season in the winter it is longer than that in summer the interannual variability of the diurnal tide indicates a clear correlation with the stratospheric quasi biennial oscillation

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

observations of the diurnal tide from space abstract this study presents a climatology of mesospheric and lower thermospheric diurnal tidal winds obtained with the high resolution doppler imager hrdi on the upper atmosphere research satellite uars the observations reveal that although tidal structures are present at all times like the prevailing zonal winds they exhibit significant semiannual as well as other shorter term variations in amplitude results are presented for a period extending over more than one year from november 1991 to july 1993 the 1 1 diurnal tidal amplitude of the meridional component characterized by the value at an altitude of 90 km and a latitude of 22 ranges from a minimum at solstice of less than 20 m s 1 to an equinox maximum of over 70 m s 1 the vertical wavelength and phase of the tide show only slight variations throughout the year with a suggestion of semiannual variations in both

salt dissolution and surface subsidence in central kansas a seismic investigation of the anthropogenic and natural origin models gradual subsidence in the punkin center study area northeast reno county kansas has resulted in ponding of surface waters abandonment of at least one oil well and damage to county roads because the punkin center area is within the burrton oil field and is underlain by the hutchinson salt member surface subsidence historically has been attributed to salt dissolution of anthropogenic origin subsidence that occurred significant distances from any known well sites has been attributed to unrecorded abandoned wells or complex asymmetric patterns of salt dissolution that originated at a drillhole to ascertain the validity of the widely accepted anthropogenic salt dissolution model a 4 km seismic reflection profile was acquired along an east west oriented county road adjacent to an abandoned oil well the expectation was that the residual hutchinson salt member would be anomalously thin where maximum recorded surface subsidence occurred and thicker elsewhere contrary to expectations the residual hutch

effect of atmospheric tides on the morphology of the quiet time postsunset equatorial ionospheric anomaly longitudinal wave number four pattern in the magnetic latitude and concentration of the f region peak ion density when measured at a fixed local time in a new comparison of two data sets with observations made by the ogo 4 satellite this pattern is seen to be persistent over many days around equinox during magnetically quiet conditions close to solar maximum but can be dominated by other processes such as cross equator winds during other periods it is found that the longitudinal variability is created by a processes occurring in the dayside ionosphere a longitudinal modulation of the dayside equatorial fountainisthemostlikelydrivingmechanism throughcomparisonwithgwsm 02model it isshownthatthepredictedmodulationofthedaysidethermosphericwindsandtemperaturesat e region altitudes created by non migrating diurnal tides can explain the modulation in the dayside equatorial fountain this result highlights the importance of understanding the temporal variability of tropospheric weather systems on our understanding and possible predictability of the development of the f region ionosphere it may also provide a possible further means of testing our understanding of atmospheric tides on a global scale

seasonal variation of diurnal perturbations in mesopause region temperature zonal and meridional winds above fort collins colorado 40 6 n 105 w 1 on the basis of lidar observations from may 2002 through april 2003 covering both day and night we performed a harmonic analysis to extract the diurnal perturbations in mesopause region temperature zonal and meridional winds over fort collins colorado 40 6 n 105 w binned every 2 months the results were compared to predictions of the 2000 and 2002 versions of global scale wave model gswm00 and gswm02 the diurnal tidal period oscillations showed a mixture of propagating and evanescent trapped modes but the propagating modes dominated for most of the year the agreement in temperature diurnal phases between observation and gswm prediction is marginal on the other hand other than july august meridional winds the observed diurnal phases in both wind components are in good agreement with gswm predictions for most of the altitude range reported the diurnal amplitude predictions of gswm00 were reasonably close to lidar observations while other than january february the gswm02 amplitude prediction overestimated the observations typically by a factor of two we also conducted comparisons on tidal perturbations in zonal wind between radar campaigns and our lidar observations the lidar data agreed reasonably well with the mf radar data from 2000 to 2001 at nearby platteville colorado 40 2 n 104 7 w but showed considerable differences with the data from other midlatitude stations from 1992 to 1993 the dominance of the evanescent mode in the temperature diurnal tidal oscillation during the early winter november and december which reached a peak value at midnight was interesting and anomalous by invoking the more recent data november and december in 2003 as well as the diurnal temperature observations from december 1998 we report that the evanescent trapped diurnal tidal perturbations were robust and persisted from one year to the next

nonmigrating diurnal tides in the thermosphere 1 horizontal wind measurements from the hrdi and windii instruments on the upper atmosphere research satellite are analyzed to reveal the most prominent nonmigrating diurnal tidal components at 95 km the eastward propagating diurnal tide with zonal wave number s 3 de3 the standing s 0 diurnal oscillation d0 and the westward propagating diurnal tide with s 2 dw2 the strongest de3 occurs primarily during northern hemisphere summer fall with maximum eastward winds near the equator of order 15 ms 1 and is a vertical extension of the s 3 kelvin wave the first antisymmetric mode of de3 dominates during october april with maximum meridional winds near the equator of order 8 ms 1 d0 exists during nearly all months and is nonsymmetric about the equator with maximum northward wind amplitudes in the southern hemisphere of order 7 10 ms 1 dw2 closely resembles the first symmetric propagating mode from classical tidal theory with maximum northward wind amplitudes of order 10 12 ms 1 during september through february the combination of de3 d0 and dw2 with dw1 gives rise to significant longitude variations in the diurnal tide between 40 latitude forcing in the global scale wave model gswm is calibrated according to the above observations thus enabling global estimates of nonmigrating tidal temperatures and other fields for instance it is estimated that the temperature and eastward wind perturbations associated with de3 may be as large as 20k and 35 ms 1 at 145 km and 115 km respectively over the equatorial region during july

momentum budget of the migrating diurnal tide in the mesosphere and lower thermosphere 1 the leading terms of the momentum budget of the migrating diurnal tide are diagnosed from temperatures and geopotential height provided by thermosphere ionosphere mesosphere energetics and dynamics timed sounding of the atmosphere using broadband emission radiometry saber and the horizontal wind vector provided by timed doppler interferometer tidi the wave drag upon the tide is inferred as a residual of the classical and linear advective terms in the zonal and meridional momentum equations between 85 and 100 km the migrating diurnal tide is generally far from the classical description of chapman and lindzen 1970 the leading nonclassical terms are the meridional advection of zonally averaged momentum and wave drag effects encapsulated in the momentum residuals the magnitudes of the momentum residuals range between 50 and 150 m s 1 d 1 for the zonal component and 100 250 m s 1 d 1 for the meridional component the zonal momentum residual is generally in quadrature with the zonal wind tide while the meridional momentum residual is in antiphase with the meridional wind above 95 km winds and temperatures exhibit maximum amplitudes during the vernal equinox season but only a minor reduction in wave damping is observed our results suggest that rayleigh damping is inadequate to describe the relationship between the tide and the forces acting upon it

interannual variations of the diurnal tide in the mesosphere generated by the quasi biennial oscillation 1 we report results from a study with the numerical spectral model nsm which produces significant interannual variations in the diurnal tide applying hines s doppler spread parameterization small scale gravity waves gws drive the quasi biennial oscillation qbo and semiannual oscillation with a gw source that peaks at the equator and is taken to be isotropic and independent of season the nsm generates a qbo with variable periods around 26 months and zonal wind amplitudes close to 25 m s 1 at 30 km as reported earlier the nsm reproduces the observed equinoctial maxima in the diurnal tide at altitudes around 95 km in the present paper it is shown that the qbo also modulates the tide such that the seasonal amplitude maxima can vary from one year to another by as much as 30 to shed light on the underlying mechanisms the relative importance of the linearized advection terms is discussed which involve the meridional and vertical winds of the diurnal tide these interactions generate pronounced qbo modulations of the tide at altitudes below 50 km in the mesosphere between 50 and 80 km the signature is not well defined because of interference from the seasonal variations at altitudes above 80 km however the qbo related interannual variations of the tide are again relatively large but they are generated primarily by gw momentum deposition since the period of the qbo is variable and its phase is relative to the seasonal cycle changes the magnitude of the qbo modulation of the tide in the upper mesosphere varies considerably as our long term model simulation shows this intermittency must be attributed to nonlinear interactions and gw drag momentum deposition is discussed as a potential candidate

seasonal variations of semidiurnal tidal perturbations in mesopause region temperature and zonal and meridional winds above fort collins colorado 40 6 n 105 1 w 1 on the basis of colorado state university csu na lidar observations over full diurnal cycles from may 2002 to april 2006 a harmonic analysis was performed to extract semidiurnal perturbations in mesopause region temperature and zonal and meridional winds over fort collins colorado 40 6 n 105 1 w the observed monthly results are in good agreement with mf radar tidal climatology for urbana illinois and with predictions of the hamburg model of the neutral and ionized atmosphere hammonia sampled at the csu na lidar coordinates the observed semidiurnal tidal period perturbation within the mesopause region is found to be dominated by propagating modes in winter and equinoctial months with a combined vertical wavelength varying from 50 km to almost 90 km and by a mode with evanescent behavior and longer vertical wavelength 100 150 km in summer months most likely due to dominance of 2 2 and 2 3 tidal hough modes the observed semidiurnal tidal amplitude shows strong seasonal variation with a large amplitude during the winter months with a higher growth rate above 85 90 km and minimal amplitudes during the summer months maximum tidal amplitudes over 50 m s for wind and 12 k for temperature occur during fall equinox a detailed comparison with hammonia predictions shows excellent agreement in semidiurnal phases hammonia predicted semidiurnal amplitudes generally agree well with observations however hommonia underestimates temperature amplitudes in some of the nonsummer months as well as zonal wind and meridional wind amplitudes in april and september but overestimates them in february to reveal the effects of the atmospheric background on vertical propagation of tidal modes and their relative importance in the composite semidiurnal tide during different seasons we use the lidar observed monthly mean temperature and zonal wind from the same data set as well as hammonia output to calculate the vertical wave number seasonal variations of the major tidal modes of the migrating semidiurnal tide this leads to a qualitative understanding of the lidar observed and hammonia predicted seasonal variation of the semidiurnal tidal perturbation

the two day wave in eos mls temperature and wind measurements during 2004 2005 winter 1 two day wave observations during january march 2005 are reported using the recently launched microwave limb sounder mls aboard nasa s earth observing system aura mission wave induced disturbances in temperature water vapor carbon monoxide and mls line of sight wind appear in early january peak near the end of january and persist until late february temperature and wind amplitudes as large as 9 k and 50 m s are observed near 90 km the wave disturbance is initially confined in the mid to low summer latitudes where the climatological summer easterly jet exhibits strong shear the wave then develops features akin to the third rossby gravity global normal mode with a weak temperature disturbance in the winter hemisphere anti symmetric about the equator and wind disturbance over the equator strong wind perturbation episode around 17 23 january 2005 in the mid latitude southern hemisphere coincides with a particularly intense solar proton event