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Frederick G. Finger and Raymond M. McInturff

of 12-hr temperature differences obtained from successive rawlnsonde observations over NorthAmerica. With a technique for isolating effects of solar radiation on the radiosonde instrument, it has become possible to construct a model of the middle stratospheric daily temperature variation. According tothis model, the temperature reaches a maximum near sunset and a minimum near sunrise. The amplitude ofthe oscillation is found to increase with altitude between the 30- and 5-rob levels and to depend

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Yun-Qi Ni, Bette L. Otto-Bliesner, and David D. Houghton

-resolution generalcirculation model to determine the temporal and scale dependency of these effects. The numerical model is aglobal, spectral, primitive equation model of the atmosphere with five equally spaced sigma levels in the verticaland triangular truncation at wavenumber 10 in the horizontal. A one-year seasonal simulation of the generalcirculation without mountains is compared to the ~sults from a five-year seasonal simulation of the generalcirculation with mountains. The statistical significance of the topographic

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Jeffrey M. Forbes and Henry B. Garrett

flux does not vary with season, investigationof solstice conditions only requires a transformationof the earth-sun geometry and appropriate modelingof seasonal variations in the background (zonallyaveraged) atmospheric and ionospherlc structures.It appears, then, that a study of the seasonal component of the diurnal thermospheric tide would befruitful at the present time, whereas investigation ofsemidiurnal or higher order effects must await furtherobservational data to perform a proper calibration

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L. Donner and V. Ramanathan

radiation energy balance to large increases in CH, and N,O.1. IntroductionMethane and N20 possess several strong absorption bands in the longwave radiation spectrum. Thestrength of these bands, when considered in conjunction with the observed present-day concentrationsof CH, and N20, suggest that these species mayexert a non-negligible influence on the present-dayclimate. The purpose of the present paper is toexamine in detail the effects of these species on thezonal and seasonal radiative energy budget

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Ling Wang, Marvin A. Geller, and M. Joan Alexander

W. Blackmore , 1995 : A comparison of radiosonde windfinding techniques: Micro-ART and NEXUS (Loran-C Radionavigation). Preprints,. Ninth Symp. on Meteorological Observations and Instrumentation, Charlotte, NC, Amer. Meteor. Soc., 49–54 . Nastrom , G. D. , and T. E. VanZandt , 2001 : Seasonal variability of the observed vertical wave number spectra of wind and temperature and the effects of prewhitening. J. Geophys. Res. , 106 , 14369 – 14375 . Nastrom , G. D. , T. E

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Ian Simmonds and Cher Chidzey

seasonal cycle. A better fitover polar regions is most evident. It is found that the inclusion of the nonlinear term in the parameterization makes little change in theaccuracy to ~hich the data are fitted. However, the explicit inclusion of the effects of clouds is found to beimportant. The analysis also reveals that clouds exert a significant feedback mechanism on climate. Whenthe infrared flux formula is tuned to fit the later satellite data set, the implied extent of this feedback lieswithin the

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R. B. Smith

results of linear theory, othercauses of steepening such as mountain asymmetry, vertical variation of wind, stability, density and mountain isolation can be estimated. The nonlinear effects associated with partial reflection from the tropopauseare found to be very important in certain situations. The theoretical ideas of wave steepening are in qualitative agreement with previous case studies of flowover large mountains and with seasonally averaged measurements of stratospheric turbulence. The

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William J. Randel and Fei Wu

/ddle stratosphere. Both upper- and lower-levelanomalies contribute important fractions to the midlatitude column amounts. The lower-level maxima have abroad latitudinal structure (~15~-60-), and collocation with the strongest background gradients suggests thatthese anomalies result from mean vertical transport. The middle stratosphere signal maximizes in the subiropics( 10--40-) and is likely due to uiWogen-related chemical effects (which are in turn due to transport variations).The vertically in-phase seasonal

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Marvin A. Geller, Eric R. Nash, Mao Fou Wu, and Joan E. Rosenfield

variations in the seasonal means of the vertical component of the residualcirculation and ozone mixing ratios are consistent with what would be expected from the ozone variations beingdue to differences in the ozone transport, although transport effects cannot easily be distinguished from photochemical effects above the altitude of the ozone mixing ratio peak. Finally, variations in total ozone areexamined in comparison with residual circulations variations. A one to two month phase lag is seen in

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M. Ference Jr., W. G. Stroud, J. R. Walsh, and A. G. Weisner

temperatures. Within the framework ofthe basic assumptions and the analysis presented here,the probable error in the temperature measurementsdoes not exceed 3 per cent, with the possible exceptionof those few cases where the wind error is large.6. SummaryIn six Aerobee firings, 32 measurements of thetemperatures and winds have been obtained in theregion of the atmosphere between 30 and 80 km at32"N. Firings were made during all seasons. No clearcut diurnal or seasonal temperature effects were observed

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