Physical Sciences and Mathematics Commons^™

One-Gas Models With Height-Dependent Mean Molecular Weight: Effects On Gravity Wave Propagation, R. L. Walterscheid, Michael P. Hickey Ph.D.

Publications

Many models of the thermosphere employ the one-gas approximation where the governing equations apply only to the total gas and the physical properties of the gas that depend on composition (mean molecular weight and specific heats) are height-dependent. It is further assumed that the physical properties of the gas are locally constant; thus motion-induced perturbations are nil. However, motion in a diffusively separated atmosphere perturbs local values of mean molecular weight and specific heats. These motion-induced changes are opposed by mutual diffusion of the constituent gases, which attempts to restore diffusive equilibrium. Assuming that composition is locally constant is equivalent …

Reflection Of A Long-Period Gravity Wave Observed In The Nightglow Over Arecibo On May 8–9, 1989?, Michael P. Hickey Ph.D.

Publications

During the Arecibo Initiative for Dynamics of the Atmosphere (AIDA) campaign in 1989 a characteristic of gravity wave perturbations observed in mesopause region airglow emissions was that airglow brightness fluctuations and airglow-derived temperature fluctuations often occurred either in phase or in antiphase. This stimulated the development of a theory suggesting that such in-phase fluctuations were most probably the result of strong reflections occurring in the mesosphere and lower thermosphere region. Recent examination of a particular wave event and application of simple WKB-type theory has appeared to support this hypothesis. Here we use a full-wave model and a WKB-type model, each …

Acoustic Wave Heating Of The Thermosphere, Michael P. Hickey Ph.D., G. Schubert, R. L. Walterscheid

Publications

A numerical model is used to study the dissipation in the thermosphere of upward propagating acoustic waves. Whereas dissipating gravity waves can cool the upper atmosphere through the effects of sensible heat flux divergence, it is found that acoustic waves mainly heat the thermosphere by viscous dissipation. Though the amplitudes of acoustic waves in the atmosphere are poorly constrained, the calculations suggest that dissipating acoustic waves can locally heat the thermosphere at rates of tens of kelvins per day and thereby contribute to the thermospheric energy balance. It is shown that viscous heating cannot be calculated from the divergence of …

Airglow Variations Associated With Nonideal Ducting Of Gravity Waves In The Lower Thermosphere Region, Michael P. Hickey Ph.D.

Publications

A numerical full-wave model is used to study the response of the O2 atmospheric airglow to ducted gravity waves in the mesopause region. For an isothermal, quasi-adiabatic, and motionless background atmosphere the calculated phase differences between airglow brightness fluctuations and fluctuations of temperatures derived from the airglow, as given by Krassovsky's ratio, are in good agreement with the predictions of published theory. Significant departures from the predictions of the basic theory are obtained when we consider ducting in the presence of the eddy and molecular diffusion of heat and momentum in a nonisothermal background atmosphere. Wind shears also affect the …

Climatology And Modeling Of Quasi-Monochromatic Atmospheric Gravity Waves Observed Over Urbana Illinois, J. H. Hecht, R. L. Walterscheid, Michael P. Hickey Ph.D., S. J. Franke

Publications

From analyzing nine months of airglow imaging observations of atmospheric gravity waves (AGWs) over Adelaide, Australia (35°S) [Walterscheid et al., 1999] have proposed that many of the quasi-monochromatic waves seen in the images were primarily thermally ducted. Here are presented 15 months of observations, from February 1996 to May 1997, for AGW frequency and propagation direction from a northern latitude site, Urbana Illinois (40°N). As Adelaide, Urbana is geographically distant from large orographic features. Similar to what was found in Adelaide, the AGWs seem to originate from a preferred location during the time period around summer solstice. In …

Gravity Wave Propagation Directions Inferred From Satellite Observations Including Smearing Effects, Jason S. Brown, Michael P. Hickey Ph.D.

Publications

We simulate space-based, sublimb viewing observations of airglow brightness fluctuations caused by atmospheric gravity wave interactions with the O2 atmospheric airglow, and we demonstrate that because of the geometry associated with such observations, the brightness fluctuations observed for the optically thick 0–0 band emission will always appear stronger for waves traveling toward the observer (the satellite). The effect should be most noticeable for waves having relatively small vertical wavelengths (∼10 km) and horizontal wavelengths of 50 km or greater. For waves of short (∼100 km) horizontal wavelength, the brightness fluctuation anisotropy with respect to viewing direction may also be evident …

Secular Variations Of Oi 5577 Å Airglow In The Mesopause Region Induced By Transient Gravity Wave Packets, Michael P. Hickey Ph.D., R. L. Walterscheid

Publications

We employ a 2-dimensional, time-dependent, fully nonlinear model of minor species in the mesopause region and our Spectral Full-Wave Model to simulate the response of minor species and the OI 5577 Å airglow to a gravity wave packet in the mesopause region. Gravity waves affect the time-averaged distribution of minor species in the mesosphere and lower thermosphere (MLT) region through constituent fluxes induced by violation of the non-acceleration conditions due to wave transience and dissipation. In addition, wave perturbed chemistry can induce a flux of chemically active species. Simulations are performed with nominal values of eddy diffusion coefficients in the …

Secular Variations Of Atomic Oxygen In The Mesopause Region Induced By Transient Gravity Wave Packets, Michael P. Hickey Ph.D., R. L. Walterscheid, Philip G. Richards

Publications

We employ a 2-dimensional, time-dependent, fully nonlinear model of minor species in the mesopause region and our Spectral Full-Wave Model to simulate the response of atomic oxygen (O) to a gravity wave packet in the mesopause region. We demonstrate that gravity waves affect the time-averaged distribution of O in the mesosphere and lower thermosphere (MLT) region through the constituent fluxes the waves induce. Our conclusions are based on simulations of two wave packets that violate the non-acceleration conditions through transience and dissipation. The net cycle-averaged effect of the waves is to significantly increase (by as much as 50%) the O …

Resolving Ambiguities In Gravity Wave Propagation Directions Inherent In Satellite Observations: A Simulation Study, Michael P. Hickey Ph.D., Jason S. Brown

Publications

We simulate space-based, sub-limb viewing observations of airglow brightness fluctuations caused by atmospheric gravity wave interactions with the O2 atmospheric airglow, and we demonstrate that, due to the geometry associated with such observations, the brightness fluctuations observed for the optically thick 0–0 band emission will always appear stronger for waves traveling towards the observer (satellite). The effect should be most noticeable for waves having relatively small vertical wavelengths (∼10 km) and horizontal wavelengths of 50 km or greater. For waves of short (∼100 km) horizontal wavelength, the brightness fluctuation anisotropy with respect to viewing direction may also be evident in …

Observations And Interpretation Of Gravity Wave Induced Fluctuations In The O I (557.7 Nm) Airglow, G. Schubert, R. L. Walterscheid, Michael P. Hickey Ph.D., C. A. Tepley

Publications

Observations of fluctuations in the intensity and temperature of the O I (557.7 nm) airglow taken at Arecibo in 1989 are reported and interpreted on the assumption that they are caused by gravity waves propagating through the emission layer. The data give the magnitude of Krassovsky's ratio as 3.5 ± 2.2, at periods between about 5 and 10 hours. Comparison with theory shows that the gravity waves responsible for the measured airglow variations must have long wavelengths of several thousand kilometers. The observed phases of Krassovsky's ratio are in good agreement with theoretically predicted values at the long wavelengths and …

A Note On Gravity Wave-Driven Volume Emission Rate Weighted Temperature Perturbations Inferred From O₂ Atmospheric And O I 5577 Airglow Observations, Michael P. Hickey Ph.D., Richard L. Walterscheid

Publications

A full-wave dynamical model and chemistry models that simulate ground-based observations of gravity wave-driven O₂ atmospheric and O I 5577 airglow fluctuations in the mesopause region are used to demonstrate that for many observable gravity waves modeling is required to infer temperature perturbation amplitudes from airglow observations. We demonstrate that the amplitude of the altitude-integrated volume emission rate weighted temperature perturbation differs by at least about 30% from the amplitude of the temperature perturbation of the major gas in the vicinity of the peak of the airglow volume emission rate for gravity waves with horizontal phase speeds less than about …

Full-Wave Modeling Of Small-Scale Gravity Waves Using Airborne Lidar And Observations Of The Hawaiian Airglow (Aloha-93) O(¹S) Images And Coincident Na Wind/Temperature Lidar Measurements, Michael P. Hickey Ph.D., Michael J. Taylor, Chester S. Gardner, Christian R. Gibbons

Publications

Measurements were made of mesospheric gravity waves in the OI (5577 Å) nightglow observed from Maui, Hawaii, during the Airborne Lidar and Observations of Hawaiian Airglow (ALOHA-93) campaign. Clear, monochromatic gravity waves were observed on several nights. By using a full-wave model that realistically includes the major physical processes in this region, we have simulated the propagation of four waves through the mesopause region and calculated the O(¹S) nightglow response to the waves. Mean winds derived from Na wind/temperature lidar observations were employed in the computations. Wave amplitudes were calculated based on the requirement that the observed and …

Numerical Simulations Of Gravity Waves Imaged Over Arecibo During The 10-Day January 1993 Campaign, Michael P. Hickey Ph.D., R. L. Walterscheid, Michael J. Taylor, William Ward, G. Schubert, Qihou Zhou, Francisco Garcia, Michael C. Kelly, G. G. Shepherd

Publications

Recently, measurements were made of mesospheric gravity waves in the OI (5577 Å) nightglow observed from Arecibo, Puerto Rico, during January 1993 as part of a special 10-day campaign. Clear, monochromatic gravity waves were observed on several nights. By using a full-wave model that realistically includes the major physical processes in this region, we have simulated the propagation of two waves through the mesopause region and calculated the O(¹S) nightglow response to the waves. Mean winds derived from both UARS wind imaging interferometer (WINDII) and Arecibo incoherent scatter radar observations were employed in the computations as were the …

A Chemical-Dynamical Model Of Wave-Driven Sodium Fluctuations, Michael P. Hickey Ph.D., John M.C. Plane

Publications

A comprehensive chemical-dynamical model is used to investigate the interaction of gravity waves with twenty minor species involved in the atomic sodium chemistry in the mesopause region. We find that chemistry becomes important on the underside of the sodium layer, primarily below 85 km altitude, where the relative importance of chemistry in wave-driven sodium fluctuations increases with increasing wave period and increasing horizontal wavelength. We also find that for altitudes below 80 km an adequate determination of the effects of chemistry in these fluctuations requires the inclusion of several reactions related to ozone chemistry. However, the atomic Na density is …

New Sources For The Hot Oxygen Geocorona: Solar Cycle, Seasonal, Latitudinal, And Diurnal Variations, Michael P. Hickey Ph.D., P. G. Richards, D. G. Torr

Publications

This paper demonstrates the variability of thermospheric sources of hot oxygen atoms. Numerical calculations were performed for day and night, high and low solar activity, summer and winter, and low- and middle-latitude conditions. Under most conditions, reactions involving metastable species are more important hot O sources than previously considered dissociative recombination of O2+ and NO+. All the hot O sources are an order of magnitude lower at midnight than at noon. At night, dissociative recombination of O2+and NO+ are the most important sources. Quenching of vibrationally excited N2 (N2*) by O is the most important metastable source at night. Above …

Wave-Modified Mean Exothermic Heating In The Mesopause Region, Michael P. Hickey Ph.D., R. L. Walterscheid

Publications

We employ a model of wave-driven OH nightglow fluctuations to calculate the effects of gravity waves on the chemical exothermic heating due to reactions involving odd hydrogen and odd oxygen species in the mesopause region. Using a model based on time means and deviations from those means, it is demonstrated that gravity waves contribute to the time-average exothermic heating. The effect can be significant because the fractional fluctuations in minor species density can be substantially greater than the fractional fluctuation of the major gas density. Our calculations reveal that the waves mitigate the exothermic heating, demonstrating their potential importance in …

Simulations Of The Effects Of Water Vapor, Cloud Liquid Water, And Ice On Amsu Moisture Channel Brightness Temperatures, Bradley M. Muller, Henry E. Fuelberg, Xuwu Xiang

Publications

Radiative transfer simulations are performed to determine how water vapor and nonprecipitating cloud liquid water and ice particles within typical midlatitude atmospheres affect brightness temperatures T-B's of moisture sounding channels used in the Advanced Microwave Sounding Unit (AMSU) and AMSU-like instruments. The purpose is to promote a general understanding of passive top-of-atmosphere T-B's for window frequencies at 23.8, 89.0, and 157.0 GHz, and water vapor frequencies at 176.31, 180.31, and 182.31 GHz by documenting specific examples. This is accomplished through detailed analyses of T-B's for idealized atmospheres, mostly representing temperate conditions over land. Cloud effects are considered in terms of …

New Sources For The Hot Oxygen Geocorona, P. G. Richards, Michael P. Hickey Ph.D., D. G. Torr

Publications

This paper investigates new sources of thermospheric non thermal (hot) oxygen due to exothermic reactions involving numerous minor (ion and neutral) and metastable species. Numerical calculations are performed for low latitude, daytime, winter conditions, with moderately high solar activity and low magnetic activity. Under these conditions we find that the quenching of metastable species are a significant source of hot oxygen, with kinetic energy production rates a factor of ten higher than those due to previously considered O2+ and NO+ dissociative recombination reactions. Some of the most significant new sources of hot oxygen are reactions involving quenching of O+(²D), O(¹D), …

Comparison Of Theories For Gravity Wave Induced Fluctuations In Airglow Emissions, R. L. Walterscheid, G. Schubert, Michael P. Hickey Ph.D.

Publications

A comparison is undertaken of theories for the gravity wave induced fluctuations in the intensity of airglow emissions and the associated temperature of the source region. The comparison is made in terms of Krassovsky's ratio ηE for a vertically extended emission region (ηE is the ratio of the vertically integrated normalized intensity perturbation to the vertically integrated normalized intensity-weighted temperature perturbation). It is shown that the formulas for ηE in the works by Tarasick and Hines (1990) and Schubert et al. (1991) are in agreement for the case of an inviscid atmosphere. The calculation of ηE using the theory of …

Gravity Wave-Driven Fluctuations In The O2 Atmospheric (0-1) Nightglow From An Extended, Dissipative Emission Region, Michael P. Hickey Ph.D., G. Schubert, R. L. Walterscheid

Publications

The wave-driven fluctuations in the O2(0-1) atmospheric nightglow is modeled and the parameter (eta) is calculated using a model that accounts for either three-body recombination of atomic oxygen atoms alone to form the O2(b exp 1 Sigma(g)(+)) state directly, or by the further inclusion of the process that allows the formation of the O2(c exp 1 Sigma(u)(-)) intermediate state. The calculations are performed for a latitude of 18 deg N and for the months of March and June. The general results, which display how (eta) varies with wave period, horizontal wavelength, season, and chemical scheme, show that for given values …

An Alternative Representation Of The Ice Canopy For Calculating Microwave Brightness Temperatures Over A Thunderstorm, Bradley M. Muller, Henry E. Fuelberg, Eric A. Smith

Publications

Passive microwave brightness temperatures (T(B)'s) at 92 and 183 GHz from an aircraft thunderstorm overflight are compared with values calculated from radar-derived hydrometeor profiles and a modified proximity sounding. Two methods for modeling particles in the ice canopy are contrasted. The first is a ''traditional'' approach employing Marshall-Palmer ice spheres. The second, or ''alternative,'' method partitions 20% of the ice water content into a Marshall-Palmer component for graupel and hail, and 80% into a modified gamma spherical particle size distribution function representing ice crystals.

Results from the alternative approach are superior to those from the traditional method in the anvil …

Seasonal And Latitudinal Variations Of Gravity Wave-Driven Fluctuations In Oh Nightglow, Michael P. Hickey Ph.D., R. L. Walterscheid, G. Schubert

Publications

The seasonal and latitudinal variations of the gravity wave-driven fluctuations in the OH nightglow are investigated theoretically using a model that accounts for emission from an extended OH layer and includes the effects of eddy diffusivities in the gravity wave dynamics. The mean (unperturbed) state is obtained from a two-dimensional, nighttime model so that mean-state number densities, temperatures and eddy diffusivities are all self-consistent. Seasonal and latitudinal variations in the background OH nightglow emission and in the propagation and dissipation characteristics of the gravity waves influence how the OH nightglow modulations due to gravity waves depend on season and latitude. …

Gravity Wave-Driven Fluctuations In Oh Nightglow From An Extended, Dissipative Emission Region, G. Schubert, R. L. Walterscheid, Michael P. Hickey Ph.D.

Publications

The theory of gravity wave-driven fluctuations in the OH nightglow from an extended source region is generalized to account for effects of eddy kinematic viscosity ν and eddy thermal diffusivity κ. In the nondiffusive case, the amplitudes and phases of vertically integrated normalized intensity 〈δI〉/〈Ī〉 and temperature 〈δTI〉/〈ĪI〉perturbations and vertically integrated Krassovsky's ratio 〈η〉 as functions of period are influenced by the upper limit of vertical integration of the extended source, especially at long periods when vertical wavelengths λᵥ are small. The effects, which include oscillations in 〈δT〉/〈Ī〉 , and 〈η〉, particularly at long …

A Simulation And Diagnostic Study Of Water Vapor Image Dry Bands, Bradley M. Muller, Henry E. Fuelberg

Publications

A Limited Area Mesoscale Prediction System (LAMPS) model simulation and special 3-hour radiosonde dataset are used to investigate warm (dry) bands in 6,7 μm water vapor satellite imagery on 6–7 March 1982. The purpose is to reveal processes resulting in the formation and evolution of the dry features that appear as curving dark streaks in the imagery. Model soundings are input to a radiative transfer algorithm to generate synthetic 6.7 μm equivalent blackbody temperatures (TB) which are compared with those from the Visible infrared Spin Scan Radiometer Atmospheric Sounder aboard the Geostationary Operational Environmental Satellite. Simulated and radiosonde-derived vertical velocity …

Wavelength Dependence Of Eddy Dissipation And Coriolis Force In The Dynamics Of Gravity Wave Driven Fluctuations In The Oh Nightglow, Michael P. Hickey Ph.D.

Publications

The theory of Walterscheid et al. (1987) to explain internal gravity wave induced oscillations in the emission intensity I and rotational temperature T of the OH nightglow was modified by Hickey (1988) to include the effects of eddy dissipation and Coriolis force. In the theory of Walterscheid et al. (1987) the ratio η = (δI/I0)/(δT/T0) (δ refers to a perturbation quantity, and a zero subscript refers to an average) was found to be independent of horizontal wavelength at long periods, while in the extended theory of Hickey (1988) some such dependence was …

Effects Of Eddy Viscosity And Thermal Conduction And Coriolis Force In The Dynamics Of Gravity Wave Driven Fluctuations In The Oh Nightglow, Michael P. Hickey Ph.D.

Publications

Recently, Walterscheid et al. (1987) have described a dynamical-chemical model of wave-driven fluctuations in the OH nightglow which incorporated a five-reaction photochemical scheme and the dynamics of linearized acoustic-gravity waves in an isothermal, motionless atmosphere. The intensity oscillation (δI) about the time-averaged intensity (I0) and the temperature oscillation (δT) about the time-averaged temperature (T0) were related by means of the complex ratio η ≡ (δI/I0)/(δT/T0). One of the main conclusions of their work was that the inclusion of dynamical effects is absolutely essential for …

Earth Observing System, Volume Iia: Data And Information System, Report Of The Eos Data Panel, Raymond Arvidson, Frederick Billingsley, Robert Chase, Pat Chavez Jr., Michael Devirian, Frederick Mosher, Et Al.

Publications

The purpose of this report is to provide NASA with a rationale and recommendations for planning, implementing, and operating an Earth Observing System data and information system that can evolve to meet the Earth Observing System's needs in the 1990s. The Earth Observing System (EOS), defined by the EOS Science and Mission Requirements Working Group, consists of a suite of instruments in low Earth orbit acquiring measurements of the Earth's atmosphere, surface, and interior; an information system to support scientific research; and a vigorous program of scientific research, stressing study of global-scale processes that shape and influence the Earth as …

The Frontal Hydraulic Head: A Micro-Α Scale (~1 Km) Triggering Mechanism For Mesoconvective Weather Systems, M. A. Shapiro, Tamara Hampel, Doris Rotzoll, F. Mosher

Publications

Measurements from the NOAA Boulder Atmospheric Observatory (BAO) 300 m tower, the National Center for Atmospheric Research (NCAR) Sabreliner aircraft, and the NOAA GOES-5 satellite, give evidence for the cross-front scale collapse of nonprecipitating surface cold-frontal zones to horizontal distances of ∼1 km or less. The leading edges of these frosts possess the characteristic structure of density current flows: an elevated hydraulic head followed by a turbulent wake. Vertical motions at the frontal heads exceed 5 m s−1 at 300 m (AGL). The ascent at the frontal head may act as a (∼1 km-scale) triggering mechanism for the release of …

Lessons Learned From The Csis [Centralized Storm Information System] (Appendix D), Frederick R. Mosher, Joseph T. Schaefer

Publications

Various attempts have been made to give up-to-the-minute meteorological observations to forecasters. However, the meteorologist's inability to assimilate all the real-time data is a significant barrier to the improvement of short-term forecasts and warnings. Historically, failure to resolve this problem has plagued mesoscale forecast experiments. This article discusses the joint effort of NWS, NESS, NASA, and SSEC to develop a system to aid the forecaster in evaluating data.

Functional And Performance Requirements Of The Next Noaa-Kansas City Computer System (Appendix G), Frederick R. Mosher

Publications

The NOAA computer system in Kansas City, Missouri, was scheduled for a computer upgrade and this is part of the report listing the critical functional and performance requirements for that system in 1984. The system needed to communicate with all the other offices at that center in Kansas City.