The global‐scale wave model (GSWM) is used to investigate mesospheric and lower thermospheric migrating nonmigrating diurnal tidal components that propagate upward from the troposphere, where they are excited by latent heat release associated with deep tropical convection. Our forcing parameterization derived a 7‐year database of global cloud imagery. GSWM response sufficiently large modulate dominant radiatively tide in middle upper atmosphere during every month year. Five additional...

A newly discovered 1000‐km scale longitudinal variation in ionospheric densities is an unexpected and heretofore unexplained phenomenon. Here we show that vary with the strength of non‐migrating, diurnal atmospheric tides are, turn, driven mainly by weather tropics. strong connection between tropospheric conditions unexpected, as these upward propagating are damped far below peak density. The observations can be explained consideration dynamo interaction lower ionosphere (E‐layer) daytime....

We overview the results of a series global‐scale wave model (GSWM) calculations we designed to quantify mesospheric and lower thermospheric migrating nonmigrating semidiurnal tidal response large‐scale tropospheric latent heat release associated with deep tropical convection. Our forcing is based on 7‐year database global cloud imagery that also characterized herein. The combined responses components are sufficiently large modulate radiatively excited tide in upper atmosphere during every...

We report on new global‐scale wave model (GSWM) predictions for the migrating solar tide in troposphere, stratosphere, mesosphere and lower thermosphere. The revision, hereafter GSWM‐98, includes an updated gravity (GW) stress parameterization modifications to background atmosphere based 6‐year monthly averaged Upper Atmosphere Research Satellite (UARS) climatologies. UARS Halogen Occultation Experiment Microwave Limb Sounder ozone data are used define strato‐mesospheric tidal source, while...

Recent updates and extensions to a steady‐state two‐dimensional linearized model of global‐scale atmospheric waves have facilitated improved calculations the subset those which are subharmonics solar day propagate with apparent motion sun. The improvements briefly described some updated predictions migrating diurnal component highlighted. latter represent first numerical modeling effort examine seasonal variability harmonic as it propagates into mesosphere lower thermosphere.

The SABER instrument on the TIMED satellite provides unprecedented geographical coverage for determination and study of atmospheric tides. However, slow local time precession rate can cause longer‐term temperature variations to alias into tidal signals. A new method analyzing data tides has been developed circumvent this difficulty, but at expense temporal resolution fields, i.e., 120‐day mean structures are obtained. In work, we apply derive a series structures, extending between 20 120 km...

We report on a series of simulations with the National Center for Atmospheric Research (NCAR) thermosphere‐ionosphere‐mesosphere‐electrodynamics general circulation model (TIME‐GCM) which were designed to replicate and facilitate interpretation longitudinal structure discovered in IMAGE satellite airglow observations equatorial ionization anomaly (EIA) at far‐ultraviolet (FUV) 135.6‐nm wavelength during March–April 2002 equinox. Our TIME‐GCM results indicate that four‐peaked variation EIA...

Observations of the mesosphere and lower thermosphere winds obtained by High Resolution Doppler Imager (HRDI) on Upper Atmosphere Research Satellite (UARS) during 1991 to 1995 reveal a semiannual variation in amplitude (1, 1) diurnal tide. The global‐scale wave model (GSWM) represents first numerical modeling attempt at simulating this seasonal variability, preliminary comparison GSWM tidal results with HRDI measurements is presented. tests point some vital unresolved questions regarding...

In atmospheric and space environment studies it is key to understand quantify the coupling of regions solar impacts on whole atmosphere system. There thus a need for numerical model that encompasses can self‐consistently simulate dynamic, physical, chemical, radiative, electrodynamic processes are important Sun‐Earth This goal developing National Center Atmospheric Research (NCAR) Whole Atmosphere Community Climate Model (WACCM). this work, we report development preliminary validation...

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 monthly mean amplitudes phases seven tidal components presented at altitudes between 85 105 km latitudes 45°S 45°N (westward propagating wave numbers 2, 3, 4; standing tide; eastward 1, 3). The observed seasonal variations agree well with 1991–1994 UARS results 95 km. Comparisons TIDI global...

Coupling between the troposphere and lower thermosphere due to upward propagating tides is investigated using temperatures measured from SABER instrument on TIMED satellite. The data analyzed here are confined 20–120 km altitude ±40° latitude during 20 July September 2002. Apart migrating (Sun‐synchronous) tidal components, predominant feature seen (from satellite frame) this period a wave‐4 structure in longitude with extrema of up ±40–50 K at 110 km. Amplitudes longitudes maxima evolve as...

An unusually long data set was acquired at the sodium lidar facility Colorado State University (41N, 105W), between Sep 18 and Oct 01, 2003, including a 9‐day continuous observation. This time is enough to average out perturbations of gravity waves short‐period planetary waves. As such, it can be used define tidal‐period in temperature horizontal wind. Assuming mixing ratio constant motion, observed oscillation density follows that vertical Thus, defines wind vector. The amplitudes phases...

The plausible effect of atmospheric tides on the longitudinal structure equatorial ionosphere is observed by FORMOSAT‐3/COSMIC (F3/C) constellation during September Equinox, 2006, near solar minimum. was first reported in IMAGE satellite airglow observations at far‐ultraviolet (FUV) 135.6‐nm wavelength March 2002, maximum. global three‐dimensional ionospheric electron density F3/C shows a prominent four‐peaked wave‐like enhancement ionization anomaly (EIA). vertical structures reveal that...

A set of numerical experiments have been conducted using the National Center for Atmospheric Research Thermosphere-Ionosphere-Mesosphere-Electrodynamics General Circulation Model (NCAR TIME-GCM) to understand effects quasi-two-day wave (QTDW) on middle atmosphere horizontal wind and temperature fields. zonal wavenumber three perturbation with a period 48 hours latitudinal structure identical (3, 0) Rossby-gravity mode has included at lower-boundary model. response in fields is observed...

A quasi‐16‐day wave in the mesosphere and lower thermosphere is investigated through analyses of radar data during January/February 1979 numerical simulations for various background wind conditions. Previous workers have examined about 19 days tropospheric stratospheric January 10–28, 1979, present conflicting evidence as to whether a large westward propagating wavenumber 1 oscillation observed this period can be identified terms second symmetric Rossby normal mode zonal 1, commonly referred...

The capabilities of the global‐scale wave model (GSWM) [ Hagan et al. , 1995, 1999] are extended to include migrating thermospheric solar tides. GSWM tidal forcing parameterization is based on neutral gas heating calculated from first principles in National Center for Atmospheric Research (NCAR) thermosphere/ionosphere electrodynamics general circulation (TIE‐GCM). This time that a physics‐based scheme has been used like GSWM. Previous two‐dimensional steady state linear models exospheric...

A steady state two‐dimensional linearized model that extends from the ground into thermosphere and captures salient features of migrating diurnal semidiurnal tidal components is used to investigate comparative importance principal sources these waves. The results, which have previously gone unreported in literature, demonstrate nonnegligible effects atmospheric absorption solar radiation at infrared (in troposphere) ultraviolet stratosphere) wavelengths on mesospheric lower thermospheric...

We used the National Center for Atmospheric Research thermosphere‐ionosphere‐mesosphere‐electrodynamics general circulation model (TIME‐GCM) to calculate variability of migrating diurnal tide in a January through December 1993 simulation. While TIME‐GCM captures salient features latitudinal, altitudinal, and seasonal tide, upper mesospheric meridional wind amplitudes are somewhat smaller than those that have been observed from ground space. The discrepancies may be attributable unresolved...

We present results of a series numerical experiments for January conditions using linearized spectral model which includes realistic mean winds and dissipation. These were designed to characterize the propagation characteristics (3,0) mixed Rossby‐gravity mode through middle atmosphere into lower thermosphere. Our suggest that wave magnitude is extremely sensitive zonal assumed in calculations. In particular, our comparatively weak eastward stratomesospheric jet during northern hemisphere...

A new meteor radar has been deployed at Esrange (68°N, 21°E) near Kiruna in Sweden. The used to measure winds and tides the Arctic mesosphere/lower thermosphere region over interval August 1999 July 2000. Conspicuous features of measured mean include a strong shear up 5 m s −1 km summer zonal flow, resulting eastward flows excess 30 upper heights observed (97 km). An equatorward meridional flow is winter, which reaches maximum values ∼13 jet. Poleward comparison weak only occurs equinoxes....

Using the TIMED Doppler interferometer (TIDI) mesospheric and lower thermospheric neutral‐wind multiyear data set (2002–2007) NCAR TIME General Circulation Models (GCM) 1.2 annual run results (2002–2005) at TIDI sampling points, we study migrating diurnal tide's global distribution, interannual, seasonal variations in connection with mean zonal wind interannual variations. A strong quasi‐biennial oscillation (QBO) effect on tide was observed reproduced to a lesser degree TIME‐GCM run. The...

The propagation characteristics of the first symmetric or (1,1) tidal mode are investigated numerically for a background atmosphere characterized by mean winds, meridional temperature gradients, and mechanical thermal dissipation. Mechanical dissipation parameterized through effective Rayleigh friction Newtonian cooling coefficients. primary effects to produce an amplitude peak in vicinity 90 km, increase vertical wavelength with height from 80 100 km broadening spreading oscillation higher...

Numerical experiments that explore the effects of tides tropospheric origin on upper and middle atmosphere reveal strong signatures an eastward propagating zonal wave number 3 diurnal tide (DE3), which peaks near 110 km penetrates into thermosphere. We demonstrate nonmigrating tidal dissipation dominated by DE3 in mesosphere lower thermosphere (MLT) strongly accelerates mean wind field, affecting both altitude magnitude low‐latitude jets. also quantify, for first time, a stationary planetary...

This study demonstrates that the diurnal cycle of net radiative heating in troposphere accounts for considerable longitudinal variability and semidiurnal tidal fields mesosphere lower thermosphere (MLT) (∼80–120 km), whereas previously it was thought latent associated with deep tropical convection is predominant driver this variability. The rates used are derived from flux products by NASA Goddard Institute Space Studies (GISS), model employed to estimate corresponding MLT tides Global‐Scale...

A number of recent studies have highlighted the observational evidence for a coupling between atmospheric tides in thermosphere and electron density structure ionosphere. The most commonly proposed mechanism to explain this is an electrodynamic at E region altitudes ion drifts F altitudes. However, based on both from satellite missions such as those neutral winds associated with nonmigrating altitudes, considering theoretical effects ionosphere, more than one must be considered. We use Sami2...