on temperature inversions and the mesospheric surf zone 1 mesospheric thermal inversions are investigated in a numerical simulation with the whole atmosphere community climate model an upward extension of the national center for atmospheric research s community climate model the seasonal character spatial extent and magnitude of the inversion layers are realistic during winter in the model the occurrence of wintertime inversions is a direct consequence of the rapid decay with height of vertically propagating planetary waves which induces large temperature perturbations in the upper mesosphere to maintain hydrostatic equilibrium the magnitude of the inversions is highly correlated with planetary wave amplitude so that large inversions develop during episodes of planetary wave amplification gravity waves do not play a major direct role in the formation of the inversions because the largest thermal tendencies associated with gravity wave breaking occur well above the range of altitudes where inversions are found however gravity waves play an essential indirect role because they set up a critical line in the upper mesosphere where rossby waves break in the mesospheric surf zone

an assessment of the quality of halogen occultation experiment temperature profiles in the mesosphere based on comparisons with rayleigh backscatter lidar and inflatable falling sphere measurements 1 bias errors for retrieved temperature profiles t p from the halogen occultation experiment haloe are evaluated by pairing with nearby soundings from ground based rayleigh lidar and from inflatable falling spheres findings for the mesosphere must be based on large sets of pairings because an individual haloe t p measurement is somewhat noisy and may not view the same atmospheric structure simulated estimates of total bias errors for the haloe profiles are of the order of 2 or 5 k the average biases with the lidar profiles at 44 n 6 e are within 3 k from 33 to 66 km and 4 k to 74 km at least when zonal easterlies and reduced wave activity prevail tidal effects can account for most of that difference comparisons with shipboard lidar soundings that begin near 100 km indicate no significant bias even in the 77 to 85 km range similar comparisons with falling sphere profiles at cape canaveral and wallops island indicate no significant bias from 40 to 66 km and 71 to 85 km haloe profiles are warmer than sphere values from 67 to 70 km but this is also the altitude region where the sphere profile has greater uncertainties for those months when the lidar soundings indicate inversion layers the sets of profiles paired with lidar indicate that the haloe t p is somewhat colder in the upper mesosphere in part owing to the effects of limb path averaging of horizontal structure by haloe and its inability to completely resolve the inversion layer maximum on the basis of the combined sets of findings it is concluded that most of the error in a single haloe t p is random except where there is a sharp inversion daily zonal averages of the haloe profiles are accurate and useful for defining the seasonal and longer term variations of t p in the mesosphere

a review of the mesosphere inversion layer phenomenon an active topic of current research in aeronomy is the study of the dynamics of the mesosphere and lower thermosphere mlt from 60 to 130 km especially in regard to the influences that govern variability the physical processes of this region are diverse and complex with strong coupling between the mlt and the adjacent atmospheric regions brought about largely by the propagation and dissipation of atmospheric gravity waves gws from sources above and below the measurements of mlt winds and temperatures required for such studies represent daunting technical challenges at low and midlatitudes the mesosphere inversion layer mil phenomenon a 10 km wide region of enhanced temperatures t 15 50k is observed with great regularity in both the upper mesosphere 60 70 km and the mesopause 90 100 km observations are largely based upon rayleigh and na temperature lidar systems but coherent radar observations have shown that the mil phenomenon is linked to layers of turbulence occurring in both the topside and the bottomside regions gw activity is believed to play an important role in the development of a linkage between the mil and the tidal structure through gw coupling that results in an amplification of the tidal thermal structure this linkage is readily evident for the upper mil but is seen only occasionally for the lower mil further study of mil properties should emphasize continual 24 hour temperature observations especially for the lower mil region to confirm the linkage of the development of the mil to the mlt tidal structure

momentum flux spectrum of convectively forced internal gravity waves and its application to gravity wave drag parameterization part ii impacts in a gcm waccm abstract impacts of a spectral parameterization of gravity wave drag gwd induced by cumulus convection gwdc in the ncar whole atmosphere community climate model waccm1b are investigated in the spectral gwdc parameterization reference wave momentum flux spectrum is launched at cloud top and analytically calculated based on the physical properties of convection and the large scale flow the cloud top wave momentum flux is strong mainly in the tropics and midlatitude storm track regions and exhibits anisotropy and spatiotemporal variability the anisotropy and variability are determined by the distributions and variations of convective activities the moving speed of convection and horizontal wind and stability in convection regions zonal mean zonal gwdc has a maximum of 13 27 37 50 m s 1 day 1 in the mesosphere in january july impacts of gwdc on zonal wind appear mainly in the low to midlatitudes of the upper stratosphere and mesosphere in these regions biases of zonal wind with respect to

a climatology of gravity wave motions in the mesopause region at adelaide australia abstract a statistical study of gravity wave motions in the mesosphere and lower thermosphere measured with a mf partial reflection radar located at buckland park new adelaide 35 s 138 e in the period november 1933 to december 1984 is presented the analyses am confined to waves with ground based periods between 1 and 24 h time height cross sections show that the mean square amplitudes u 2 and v 2 of the zonal and meridional perturbation velocities respectively vary in a predominantly semiannual manner such that the minima in wave activity coincide with the reversals in the zonal circulation in the middle atmosphere in most instances v 2 is greater than u 2 which together with the small but nonzero u v fluxes shows that the gravity wave field is partially polarized a technique similar to that used to analyse partially polarized electromagnetic waves suggests that on a seasonal basis the wave field is polarized by about 10 to 20 but for shorter periods the degree of polarization may be signi

h3 as an ionospheric sounder of jupiter and giant planets an observational perspective thirty years of observations of h3 on jupiter have addressed many complex questions about the physics of the ionospheres of the giant planets spectroscopy imaging and imaging spectroscopy in the

mesospheric inversions and their relationship to planetary wave structure 1 mesospheric inversions are studied in vertical soundings from the french lidar at observatoire de haute provence and in synoptic global structure that was observed simultaneously by the uars satellite the latter provides the instantaneous three dimensional 3 d structure of the circulation that accompanies mesospheric inversions a numerical simulation with a 3 d primitive equation model is then shown to reproduce major features of the observed behavior both reveal an extensive pattern of inverted thermal structure the behavior is closely related to planetary waves which in the model experience strong absorption in the upper mesosphere and lower thermosphere inverted thermal structure mirrors the synoptic pattern of potential vorticity which marks the polar night vortex both are strongly distorted during stratospheric warmings when inverted thermal structure at midlatitudes is favored the region of negative lapse rate coincides with those altitudes where planetary wave temperature undergoes an abrupt phase shift wave temperature is then driven out of phase with wave geopotential this alters the vertical structure of planetary waves from westward tilt and upward amplification below the inversion to nearly barotropic structure and upward decay above the inversion accompanying the upward decay of planetary waves above the inversion is a decay of flow distortion as the disturbed vortex is gradually restored toward polar symmetry

observed coupling of the mesosphere inversion layer to the thermal tidal structure rayleigh lidar observations of mesosphere temperature profiles obtained from 40 to 100 km from logan utah 41 7 111 8 w altitude 1 9 km over 10 nights in late february 1995 revealed an interesting development between 60 to 75 km of a winter mesosphere inversion layer with an amplitude of 20 30 k and a downward phase progression of 1 km hr the data also showed two altitude regions exhibiting significant cooling of 10 30 k in extent these were located below and above the peak of the inversion layer respectively at altitudes of 50 55 km and 70 80 km when these results were compared with the predictions of a global wave scale model gswm the observed thermal mesosphere structure is similar to the computed composite tidal structure based upon the semi diurnal and diurnal tides with the exception that observed amplitudes of heating and cooling are 10x larger than predicted gswm values we suggest that these events over utah are caused through a localized mechanism involving the coupling of gravity waves to the mesopause tidal structure

measurements of superadiabatic lapse rates in the middle atmosphere a large power aperture product rayleigh scatter lidar system has been successfully built and over 175 nights of middle atmosphere temperature measurements have been obtained the high signal to noise ratio of these measurements allows the stability of the air in the upper stratosphere and mesosphere to be determined a detailed methodology has been developed to attempt to differentiate between lapse rate variations due to photon counting errors and actual geophysical variations on nights when the geophysical variations are large compared to the photon counting errors regions of convective stability and instability can be determined at a reasonably high confidence level both statistics of the layers and an image of the layers is presented for the night of may 31 1996 the measured percentage of unstable layers is in agreement with the predictions of hines 1991 as is the apparently sporadic formation and distribution of the unstable regions

mesospheric temperature inversion and gravity wave breaking more than 500 nightly mean temperature profiles have been obtained since 1981 by two rayleigh lidars located in south of france 550 km apart in the mesosphere a temperature inversion a feature persisting for several days is frequently observed simultaneously at both sites from a statistical study of the inversion characteristics it is shown that its altitude ranges from 55 72 km in winter to 70 83 km in summer while its probability of occurrence presents a semi annual variation with a maximum higher in winter than in summer and a minimum lower in may than in september the seasonal variation of the temperature inversion is shown to be very similar to that of the mst radar echoes in the mesosphere associated to turbulent layers generated by the breaking of gravity waves a crude estimate of the amplitude growth with height of a gravity wave in the presence of an inversion layer indicates that the wave will break preferably inside and above this layer the persistence of a temperature inversion during several days with amplitude as large as 40 k is tentatively explained by the heating of the turbulent layers generated by the continuous breaking of gravity waves above the secondary minimum of temperature

mesosphere inversion layers and stratosphere temperature enhancements 1 it has been known for at least 30 years that vertically narrow thermal layers form within the middle atmosphere two types of temperature enhancements the low latitude to midlatitude mesosphere inversion layer mil and the high latitude winter stratosphere temperature enhancement ste have both received much attention within the atmospheric science community because of their unexplained formation mechanisms and potential impacts on the middle atmosphere global circulation numerous experimental numerical and theoretical studies have attempted to explain certain aspects of these respective thermal layers but no one theory consistently and satisfactorily describes all the features observed we present a review of the literature and explicitly propose a classification scheme based on the different formation mechanisms suspected to cause these events for the mil we demonstrate that there are two subtypes the first one is tidally driven and tends to occur above 85 km this mil originates from large amplitude tidal waves propagating into the mesosphere and their subsequent nonlinear interactions with gravity waves which can often create the appearance of a double mil separated by approximately one vertical tidal wavelength 25 km the other subtype of mil is formed by a climatological planetary wave dissipation mechanism that occurs at a zero wind line the dissipation of the planetary wave tends to generate a mesoscale 1000 km inversion layer in the range of 65 80 km these two formation mechanisms explain a host of observed characteristics including the reason behind the downward progression of some mils and not others the different climatological nature of the two forms of mil events and the relative scarcity of mil observations at high latitudes the ste is believed to be generated by an altogether different process namely the nonlinear interaction between the polar vortex and planetary waves aleutian high the induced temperatures typically peak around 40 km and often exceed 300 k generating what appears to be a low hot stratopause when vertical temperature profiles are combined with synoptic analyses one observes that the ste is the consequence of high latitude vortex interactions creating a baroclinic atmosphere i e a downward adiabatic compression induced by an ageostropic flow we summarize the details of the relationship between this feature and sudden stratospheric warmings as well as the potential for in situ gravity wave generation we close with a review of currently unexplained mil ste features and offer new directions for future middle atmosphere thermal layer research

surface downhole electrical resistivity tomography applied to monitoring of co2 storage at ketzin germany abstractsurface downhole electrical resistivity tomography sd ert surveys were repeatedly carried out to image co2 injected at the pilot storage ketzin germany the experimental setup combines surface with downhole measurements by using a permanent electrode array that has been deployed in three wells two baseline experiments were performed during the site startup and three repeat experiments were performed during the first year of co2 injection by the time of the third repeat approximately 13 500 tons of co2 had been injected into the reservoir sandstones at about 650 m depth field data and inverted resistivity models showed a resistivity increase over time at the co2 injector the lateral extent of the related resistivity signature indicated a preferential co2 migration toward the northwest using an experimental resistivity saturation relationship we mapped co2 saturations by means of the resistivity index method for the latest repeat co2 saturations show values of up to 70 near the injectio

mesospheric inversion layers at chatanika alaska 65 n 147 w rayleigh lidar observations and analysis rayleigh lidar observations at poker flat research range chatanika alaska 65 n 147 w have yielded density and temperature measurements from 40 km to 80 km these measurements have been made under clear skies at night between november 1997 and may 2009 we have identified and characterized 79 mesospheric inversion layers mils in the 40 70 km altitude region on 56 of 117 nights of observations between august and may these 79 mils have an average amplitude of 13 k peak altitude of 61 km topside lapse rate of 6 k km depth or thickness of 3 km base altitude of 58 km bottomside gradient of 5 k km and downward vertical velocity of 0 1 km h based on the 2 h temperature profiles mils occur with a nightly occurrence rate of 48 more frequently than previously reported at arctic sites but less frequently than at lower latitude sites mils are embedded in the larger planetary wave structure mils are found to occur most commonly in january as has been reported from lower latitude sites we find that the planetary wave 1 amplitudes are a factor 1 3 larger at an altitude of 5 0 6 5 scale heights 32 39 km on days when mils are observed than when they are not observed the planetary wave 2 amplitudes are not significantly different when mils are present and absent we find that eliassen palm flux divergences at an altitude of 7 8 scale height 45 52 km are a factor 2 0 larger on nights when mils are observed than when they are not observed we also find that gravity wave potential energy densities are a factor 1 3 larger on nights when mils are observed than on nights when they are not observed

impact of gravity waves on the middle atmosphere of mars a non orographic gravity wave parameterization based on global climate modeling and mcs observations the impact of gravity waves gw on diurnal tides and the global circulation in the middle upper atmosphere of mars is investigated using a general circulation model gcm we have implemented a stochastic parameterization of non orographic gw into the laboratoire de meteorologie dynamique lmd mars gcm lmd mgcm following an innovative approach the source is assumed to be located above typical convective cells urn x wiley jgre media jgre21298 jgre21298 math 0001250 pa and the effect of gw on the circulation and predicted thermal structure above 1 pa urn x wiley jgre media jgre21298 jgre21298 math 000250 km is analyzed we focus on the comparison between model simulations and observations by the mars climate sounder mcs on board mars reconnaissance orbiter during martian year 29 mcs data provide the only systematic measurements of the martian mesosphere up to 80 km to date the primary effect of gw is to damp the thermal tides by reducing the diurnal oscillation of the meridional and zonal winds the gw drag reaches magnitudes of the order of 1 m s sol above 10 urn x wiley jgre media jgre21298 jgre21298 math 0003 pa in the northern hemisphere winter solstice and produces major changes in the zonal wind field from tens to hundreds of m s while the impact on the temperature field is relatively moderate 10 20 k it suggests that gw induced alteration of the meridional flow is the main responsible for the simulated temperature variation the results also show that with the gw scheme included the maximum day night temperature difference due to the diurnal tide is around 10 k and the peak of the tide is shifted toward lower altitudes in better agreement with mcs observations

on the origin of mesospheric bores abstract a dramatic front of airglow radiance and wave structure reported by taylor et al 1995 was attributed in a previous paper of ours dewan and picard 1998 to a manifestation of an internal undular bore in the mesosphere in the current paper we address the question of what physical process could be responsible for generating such a bore at that altitude while it is relatively easy to find sources of internal tropospheric bores including the dramatic morning glory the same cannot be said for mesospheric bores it will be argued here that a likely candidate for the generator of such bores is the interaction of gravity waves with the mean flow at a critical layer this interaction could take place within an already existing inversion layer the latter playing the role of the channel in which the bore propagates as huang et al 1998 have shown a similar wave critical level interaction may be responsible for the inversion layer in question hence we are proposing that the physical process producing the channel is the same as the one responsible for subsequently generating the bore

rayleigh lidar observations of mesospheric inversion layers at poker flat alaska 65 n 147 w rayleigh lidar measurements of the stratosphere and mesosphere have been made on an ongoing basis over a three year period at poker flat alaska 65 n 147 w these observations have yielded 27 nightly measurements of the middle atmosphere temperature profile 40 80 km these nighttime measurements are distributed between august and april mesospheric inversion layers have been observed on five occasions the average altitude of the inversion layer peak is 60 km with average amplitude of 18 k the temperature gradients on the topside of the inversion layers approach the adiabatic lapse rate the inversion layers do not exhibit the apparent downward phase velocities that are commonly observed at lower latitudes furthermore the inversion layers appear significantly less frequently than at lower latitudes the observations are discussed in terms of current models and observations at other sites

mesospheric temperature inversions as seen by isams in december 1991 a large number of mesospheric temperature inversion layers have been observed locally in recent decades notably by the network of french lidars it is shown in this paper that the improved stratospheric and mesospheric sounder on board the upper atmosphere research satellite is able to detect the presence of temperature inversions and thus allows the study of their occurrence and characteristics on a global scale during december 1991 inversions of large amplitude greater than 20 k are seen almost every day especially in mid latitudes with extent varying typically from 105 to 106 km several particularly large inversions were observed at the end of the month their correlation with assimilated stratospheric winds is consistent with the interpretation that gravity waves propagate unfiltered through the stratosphere in the regions of strong winds and break in the mesosphere the combination of high resolution lidar measurements and global satellite coverage is expected to lead to a better understanding of this significant feature of the winter mesosphere at middle latitudes

partial melting beneath a mid atlantic ridge segment detected by teleseismic pkp delays an array of six ocean bottom seismometers deployed across a segment of the mid atlantic ridge recorded pkp phases from four teleseismic earthquakes after correcting for normal moveout and elevation differences there is a systematic variation of anomalous travel time with distance from the ridge stations at the ridge axis are slowest the average anomaly at a station 16 km from the axis is 0 36 s relative to the axial stations most of this anomaly is probably caused by the presence of partial melt beneath the ridge axis perhaps concentrated primarily in the upper 30 km of the mantle the rapid variation across axis suggests that the melt is either associated with a narrow zone of buoyant upwelling or a region of veins and dikes forming a narrow transport zone connecting a deep melt production region to the crust

mesospheric inversion layer and sprites 1 the vertical structure of temperature observed by sounding of atmosphere using broadband emission radiometry saber aboard thermosphere ionosphere mesosphere energetics and dynamics timed and sprites observations made during the eurosprite 2003 2007 observational campaign were analyzed sprite observations were made at two locations in france namely puy de dome 45 46 19 2 n 02 57 44 64 e 1 464 km altitude in the french massif central and at the pic du midi 42 56 11 n 00 08 34 e 2 877 km altitude in the french pyrenees it is observed that the vertical structure of temperature shows evidence for a mesospheric inversion layer mil on those days on which sprites were observed a few events are also reported in which sprites were not recorded although there is evidence of a mil in the vertical structure of the temperature it is proposed that breaking gravity waves produced by convective thunderstorms facilitate the production of 1 sprites by modulating the neutral air density and 2 mils via the deposition of energy the same proposition has been used to explain observations of lightings as well as both mils and lightning arising out of deep convections

sodium lidar observed gravity wave breaking followed by an upward propagation of sporadic sodium layer over hefei china the university of science and technology of china ustc sodium temperature wind lidar observed a strong zonal wind shear 60 m s km near 98 km between 1315 and 1330 ut on 29 july 2013 and a cooling near 96 100 km above a warming near 90 95 km between 1330 and 1430 ut this suggests a possible gravity wave gw breaking event comparison of the lidar results with observations from a nearby meteor radar and with satellite results indicated that the gw likely broke down over a large horizontal area in addition the sodium number density suddenly increased by 10 12 times 13 000 atmos cm3 near 95 km at 1400 ut immediately following the gw breaking this sporadic sodium layer ssl which is different from most previously observed ssl events which propagate downward tended to propagate upward and also appeared 2 minutes earlier in the west channel than in the east channel the horizontal propagation direction of the ssl was aligned with the horizontal wind direction which was likely due to the propagation of a high density sodium layer from the northwest of the lidar site and was possibly related to the earlier gw breaking event