On the two-day oscillations and the day-to-day variability in global 3-D-modeling of the chemical system of the upper mesosphere/mesopause region

Abstract. The integration of the photochemical system of the upper mesosphere/mesopause region brought evidence that the system is able to respond in a nonlinear manner under certain conditions. Under the action of the diurnally-periodic insolation, the system creates subharmonic oscillations or chaos if disregarding strong diffusion, and under special conditions it possesses multiple solutions. The models used in the past were simplified and idealized in view of the number of dimensions and the consideration of the full dynamics. On the basis of our global 3-D-model of the dynamics and chemistry of the middle atmosphere (COMMA-IAP), we also found a nonlinear response in the photochemistry under realistic conditions. The model under consideration is not yet self-consistent, but the chemical model uses the dynamical fields calculated by the dynamic model. From our calculations we got period-2 oscillations of the photochemical system within confined latitudinal regions around the solstices but not during the equinoxes. The consequence of the period-2 oscillation of the chemical active minor constituents is that a marked two-day variation of the chemical heating rates is an important thermal pumping mechanism. We discuss these findings particularly in terms of the influence of realistic dynamics on the creation of nonlinear effects.

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The nonlinear effects on the characteristics of gravity wave packets: dispersion and polarization relations

Annales Geophysicae ◽

10.1007/s00585-000-1316-z ◽

2000 ◽

Vol 18 (10) ◽

pp. 1316-1324 ◽

Cited By ~ 13

Author(s):

S.-D. Zhang ◽

F. Yi ◽

J.-F. Wang

Keyword(s):

Gravity Wave ◽

Gravity Waves ◽

Middle Atmosphere ◽

Wave Packets ◽

Nonlinear Effects ◽

Wave Theory ◽

Nonlinear Propagation ◽

Waves And Tides ◽

Time Variations ◽

Isothermal Atmosphere

Abstract. By analyzing the results of the numerical simulations of nonlinear propagation of three Gaussian gravity-wave packets in isothermal atmosphere individually, the nonlinear effects on the characteristics of gravity waves are studied quantitatively. The analyses show that during the nonlinear propagation of gravity wave packets the mean flows are accelerated and the vertical wavelengths show clear reduction due to nonlinearity. On the other hand, though nonlinear effects exist, the time variations of the frequencies of gravity wave packets are close to those derived from the dispersion relation and the amplitude and phase relations of wave-associated disturbance components are consistent with the predictions of the polarization relation of gravity waves. This indicates that the dispersion and polarization relations based on the linear gravity wave theory can be applied extensively in the nonlinear region.Key words: Meteorology and atmospheric dynamics (middle atmosphere dynamics; waves and tides)

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Middle atmospheric changes caused by the January and March 2012 solar proton events

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-13-23251-2013 ◽

2013 ◽

Vol 13 (9) ◽

pp. 23251-23293 ◽

Cited By ~ 1

Author(s):

C. H. Jackman ◽

C. E. Randall ◽

V. L. Harvey ◽

S. Wang ◽

E. L. Fleming ◽

...

Keyword(s):

Atmospheric Chemistry ◽

Middle Atmosphere ◽

Michelson Interferometer ◽

Peroxy Radical ◽

Solar Proton ◽

Proton Event ◽

Neutral Atmosphere ◽

Cycle 24 ◽

Atmospheric Changes ◽

D Model

Abstract. The recent 23–30 January and 7–11 March 2012 solar proton event (SPE) periods were substantial and caused significant impacts on the middle atmosphere. These were the two largest SPE periods of solar cycle 24 so far. The highly energetic solar protons produced considerable ionization of the neutral atmosphere as well as HOx (H, OH, HO2) and NOx (N, NO, NO2). We compute a NOx production of 1.9 and 2.1 Gigamoles due to these SPE periods in January and March 2012, respectively, which places these SPE periods among the 12 largest in the past 50 yr. Aura Microwave Limb Sounder (MLS) observations of the peroxy radical, HO2, show significant enhancements of > 0.9 ppbv in the northern polar mesosphere as a result of these SPE periods. Both MLS measurements and Goddard Space Flight Center (GSFC) two-dimensional (2-D) model predictions indicated middle mesospheric ozone decreases of > 20% for several days in the northern polar region with maximum depletions > 60% over 1–2 days as a result of the HOx produced in both the January and March 2012 SPE periods. The SCISAT-1 Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE) and the Envisat Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) instruments measured NO and NO2 (~ NOx), which indicated enhancements of over 20 ppbv in most of the northern polar mesosphere for several days as a result of these SPE periods. The GSFC 2-D model was used to predict the medium-term (~ months) influence and showed that the polar middle atmosphere ozone was most affected by these solar events in the Southern Hemisphere due to the increased downward motion in the fall and early winter. The downward transport moved the SPE-produced NOy to lower altitudes and led to predicted modest destruction of ozone (5–9%) in the upper stratosphere days to weeks after the March 2012 event. Total ozone reductions were predicted to be a maximum of 1% in 2012 due to these SPEs.

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On the long term evolution of noctilucent clouds

10.5194/egusphere-egu2020-2733 ◽

2020 ◽

Author(s):

Franz-Josef Lübken ◽

Gerd Baumgarten

Keyword(s):

Water Vapor ◽

Middle Atmosphere ◽

Vapor Concentration ◽

Noctilucent Clouds ◽

Mesopause Region ◽

Water Ice ◽

Term Evolution ◽

Time Period ◽

Modern Era

<p>Some of the earliest observations in the transition region between the Earth's atmosphere and space (roughly at 80-120km) come from so called `noctilucent clouds' (NLC) which are located around 83km altitude and consist of water ice particles. They owe their existence to the very cold summer mesopause region (~130K) at mid and high latitudes. There is a long standing dispute whether NLC are indicators of climate change in the middle atmosphere. We use model simulations of the background atmosphere and of ice particle formation for a time period of 138 years to show that an increase of NLC appearance is expected for recent decades due to increased anthropogenic release of methane being oxidized to water vapor in the middle atmosphere. Since the beginning of industrialization the water vapor concentration at NLC heights has presumably increased by about 40 percent (1 ppmv). The water vapor increase leads to a large enhancement of NLC brightness. Increased cooling by enhanced carbon dioxide alone (assuming no water vapor increase) counter-intuitively would lead to a decrease(!) of NLC brightness. NLC existed presumably since centuries, but the chance to observe them by naked eye was very small before the 20th century, whereas it is likely to see an NLC in the modern era. The eruption of volcano Krakatoa in 1883 has seemingly triggered the first observation of an NLC in 1885. In this presentation we extend our analysis from middle to polar latitudes and expand comparison with observations.</p>

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Hydroxyl layer: trend of number density and intra-annual variability

Annales Geophysicae ◽

10.5194/angeo-33-749-2015 ◽

2015 ◽

Vol 33 (6) ◽

pp. 749-767 ◽

Cited By ~ 13

Author(s):

G. R. Sonnemann ◽

P. Hartogh ◽

U. Berger ◽

M. Grygalashvyly

Keyword(s):

Atomic Hydrogen ◽

Middle Atmosphere ◽

Transport Model ◽

Anthropogenic Impacts ◽

Number Density ◽

Hemispheric Differences ◽

Chemical Transport Model ◽

Mesopause Region ◽

Production Term

Abstract. The layer of vibrationally excited hydroxyl (OH*) near the mesopause in Earth's atmosphere is widely used to derive the temperature at this height and to observe dynamical processes such as gravity waves. The concentration of OH* is controlled by the product of atomic hydrogen, with ozone creating a layer of enhanced concentration in the mesopause region. However, the basic influences on the OH* layer are atomic oxygen and temperature. The long-term monitoring of this layer provides information on a changing atmosphere. It is important to know which proportion of a trend results from anthropogenic impacts on the atmosphere and which proportion reflects natural variations. In a previous paper (Grygalashvyly et al., 2014), the trend of the height of the layer and the trend in temperature were investigated particularly in midlatitudes on the basis of our coupled dynamic and chemical transport model LIMA (Leibniz Institute Middle Atmosphere). In this paper we consider the trend for the number density between the years 1961 and 2009 and analyze the reason of the trends on a global scale. Further, we consider intra-annual variations. Temperature and wind have the strongest impacts on the trend. Surprisingly, the increase in greenhouse gases (GHGs) has no clear influence on the chemistry of OH*. The main reason for this lies in the fact that, in the production term of OH*, if atomic hydrogen increases due to increasing humidity of the middle atmosphere by methane oxidation, ozone decreases. The maximum of the OH* layer is found in the mesopause region and is very variable. The mesopause region is a very intricate domain marked by changeable dynamics and strong gradients of all chemically active minor constituents determining the OH* chemistry. The OH* concentration responds, in part, very sensitively to small changes in these parameters. The cause for this behavior is given by nonlinear reactions of the photochemical system being a nonlinear enforced chemical oscillator driven by the diurnal-periodic solar insolation. At the height of the OH* layer the system operates in the vicinity of chemical resonance. The solar cycle is mirrored in the data, but the long-term behavior due to the trend in the Lyman-α radiation is very small. The number density shows distinct hemispheric differences. The calculated OH* values show sometimes a step around a certain year. We introduce a method to find out the date of this step and discuss a possible reason for such behavior.

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Plasmon-induced nonlinear response of silver atomic chains

Nanoscale ◽

10.1039/c8nr02086h ◽

2018 ◽

Vol 10 (18) ◽

pp. 8600-8605 ◽

Cited By ~ 5

Author(s):

Lei Yan ◽

Mengxue Guan ◽

Sheng Meng

Keyword(s):

Density Functional Theory ◽

Density Functional ◽

Nonlinear Response ◽

Nonlinear Effects ◽

Time Dependent ◽

Microscopic Mechanism ◽

Functional Theory ◽

Atomic Chains ◽

Dependent Density

The microscopic mechanism for plasmon-induced nonlinear effects is revealed using time-dependent density functional theory.

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Middle atmospheric changes caused by the January and March 2012 solar proton events

Atmospheric Chemistry and Physics ◽

10.5194/acp-14-1025-2014 ◽

2014 ◽

Vol 14 (2) ◽

pp. 1025-1038 ◽

Cited By ~ 34

Author(s):

C. H. Jackman ◽

C. E. Randall ◽

V. L. Harvey ◽

S. Wang ◽

E. L. Fleming ◽

...

Keyword(s):

Atmospheric Chemistry ◽

Middle Atmosphere ◽

Transport Model ◽

Michelson Interferometer ◽

Three Dimensional ◽

Peroxy Radical ◽

Solar Proton ◽

Proton Event ◽

Neutral Atmosphere ◽

D Model

Abstract. The recent 23–30 January and 7–11 March 2012 solar proton event (SPE) periods were substantial and caused significant impacts on the middle atmosphere. These were the two largest SPE periods of solar cycle 24 so far. The highly energetic solar protons produced considerable ionization of the neutral atmosphere as well as HOx (H, OH, HO2) and NOx (N, NO, NO2). We compute a NOx production of 1.9 and 2.1 Gigamoles due to these SPE periods in January and March 2012, respectively, which places these SPE periods among the 12 largest in the past 50 yr. Aura Microwave Limb Sounder (MLS) observations of the peroxy radical, HO2, show significant enhancements of > 0.9 ppbv in the northern polar mesosphere as a result of these SPE periods. Both MLS measurements and Goddard Space Flight Center (GSFC) two-dimensional (2-D) model predictions indicated middle mesospheric ozone decreases of > 20% for several days in the northern polar region with maximum depletions > 60% over 1–2 days as a result of the HOx produced in both the January and March 2012 SPE periods. The SCISAT-1 Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE) and the Envisat Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) instruments measured NO and NO2 (~ NOx), which indicated enhancements of over 20 ppbv in most of the northern polar mesosphere for several days as a result of these SPE periods. The GSFC 2-D model and the Global Modeling Initiative three-dimensional chemistry and transport model were used to predict the medium-term (~ months) influence and showed that the polar middle atmospheric ozone was most affected by these solar events in the Southern Hemisphere due to the increased downward motion in the fall and early winter. The downward transport moved the SPE-produced NOy to lower altitudes and led to predicted modest destruction of ozone (5–13%) in the upper stratosphere days to weeks after the March 2012 event. Polar total ozone reductions were predicted to be a maximum of 1.5% in 2012 due to these SPEs.

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Torsional Relaxation and Volume Response During Physical Aging in Epoxy Glasses Subjected to Large Torsional Deformations

MRS Proceedings ◽

10.1557/proc-215-81 ◽

1990 ◽

Vol 215 ◽

Cited By ~ 3

Author(s):

Maria M. Santore ◽

Gregory B. McKenna

Keyword(s):

Nonlinear Response ◽

Physical Aging ◽

Nonlinear Effects ◽

Time Shift ◽

Strain History ◽

Equilibration Time ◽

Mechanical Stimuli ◽

Thermally Induced ◽

Volume Recovery ◽

Volume Response

AbstractWe present torsional dilatometry experiments to simultaneously measure torque relaxation and volume recovery in an epoxy glass quenched from above its glass transition temperature to below it. Two strain histories are employed: one with strains of equal sizes and a second where small strains follow a large one. The baseline for the thermally induced volume recovery is insensitive to intermittent torsional strains whose magnitude can be well into the non-linear regime. The torque relaxations from equal intermittent mechanical stimuli can be superposed by a time-aging time shift in a way that indicates fast changes cease to occur at ∼104 seconds after the quench, a “mechanical equilibration” time. Stimuli of different sizes can confound superposition via nonlinear effects, but do not affect the ultimate volume recovery of the glass or its mechanical equilibration time. Our results show the signature of rejuvenation; however, this may result from the nonlinear response of the material in a nonisochoric strain history. Our data firmly show that mechanical stimuli do not erase aging or rejuvenate this epoxy.

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On the Approximation of Local and Linear Radiative Damping in the Middle Atmosphere

Journal of the Atmospheric Sciences ◽

10.1175/2009jas3286.1 ◽

2010 ◽

Vol 67 (6) ◽

pp. 2070-2085 ◽

Cited By ~ 22

Author(s):

Peter Hitchcock ◽

Theodore G. Shepherd ◽

Shigeo Yoden

Keyword(s):

Climate Model ◽

Middle Atmosphere ◽

Mechanistic Modeling ◽

Radiative Heating ◽

Spatiotemporal Variability ◽

Quadratic Term ◽

Heating Rates ◽

Temperature State ◽

Large Fluctuations ◽

Damping Rate

Abstract The validity of approximating radiative heating rates in the middle atmosphere by a local linear relaxation to a reference temperature state (i.e., “Newtonian cooling”) is investigated. Using radiative heating rate and temperature output from a chemistry–climate model with realistic spatiotemporal variability and realistic chemical and radiative parameterizations, it is found that a linear regression model can capture more than 80% of the variance in longwave heating rates throughout most of the stratosphere and mesosphere, provided that the damping rate is allowed to vary with height, latitude, and season. The linear model describes departures from the climatological mean, not from radiative equilibrium. Photochemical damping rates in the upper stratosphere are similarly diagnosed. Three important exceptions, however, are found. The approximation of linearity breaks down near the edges of the polar vortices in both hemispheres. This nonlinearity can be well captured by including a quadratic term. The use of a scale-independent damping rate is not well justified in the lower tropical stratosphere because of the presence of a broad spectrum of vertical scales. The local assumption fails entirely during the breakup of the Antarctic vortex, where large fluctuations in temperature near the top of the vortex influence longwave heating rates within the quiescent region below. These results are relevant for mechanistic modeling studies of the middle atmosphere, particularly those investigating the final Antarctic warming.

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Unexpectedly small semidiurnal tidal wind amplitudes in the mid-latitudemesopause region during September 2002

Annales Geophysicae ◽

10.5194/angeo-22-701-2004 ◽

2004 ◽

Vol 22 (2) ◽

pp. 701-704 ◽

Cited By ~ 1

Author(s):

D. Kürschner ◽

Ch. Jacobi

Keyword(s):

Phase Transition ◽

Key Words ◽

Central Europe ◽

Annual Cycle ◽

Middle Atmosphere ◽

Atmospheric Dynamics ◽

Mesopause Region ◽

Meteorology And Atmospheric Dynamics ◽

Middle Atmosphere Dynamics ◽

Waves And Tides

Abstract. The mesopause region monthly mean winds and semidiurnal tidal amplitudes and phases over Central Europe have been measured at Collm Observatory since September 1982. The regular annual cycle of the semidiurnal tidal amplitudes show maximum values during late August and September. In contrast to that, in autumn 2002 no enhancement of the tidal amplitudes was measured, while the autumn tidal phase transition occurred unusually early. Key words. Meteorology and atmospheric dynamics (middle atmosphere dynamics; waves and tides; climatology)

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Use of coupled ozone fields in a 3-D circulation model of the middle atmosphere

Annales Geophysicae ◽

10.1007/s00585-999-0415-8 ◽

1999 ◽

Vol 17 (3) ◽

pp. 415-429 ◽

Cited By ~ 9

Author(s):

T. Reddmann ◽

R. Ruhnke ◽

W. Kouker

Keyword(s):

Middle Atmosphere ◽

Lower Boundary ◽

Coupled Model ◽

Circulation Model ◽

Atmospheric Composition ◽

Heating Rates ◽

Lower Boundary Condition ◽

Detailed Chemistry ◽

Composition And Structure ◽

On Line

Abstract. With a detailed chemistry scheme for the middle atmosphere up to 70 km which has been added to the 3-D Karlsruhe simulation model of the middle atmosphere (KASIMA), the effects of coupling chemistry and dynamics through ozone are studied for the middle atmosphere. An uncoupled version using an ozone climatology for determining heating rates and a coupled version using on-line ozone are compared in a 10-month integration with meteorological analyses for the winter 1992/93 as the lower boundary condition. Both versions simulate the meteorological situation satisfactorily, but exhibit a too cold lower stratosphere. The on-line ozone differs from the climatological data between 20 and 40 km by exhibiting too high ozone values, whereas in the lower mesosphere the ozone values are too low. The coupled model version is stable and differs only above 40 km significantly from the uncoupled version. Direct heating effects are identified to cause most of the differences. The well-known negative correlation between temperature and ozone is reproduced in the model. As a result, the coupled version slightly approaches the climatological ozone field. Further feedback effects are studied by using the on-line ozone field as a basis for an artificial climatology. For non-disturbed ozone conditions realistic monthly and zonally averaged ozone data are sufficient to determine the heating rates for modelling the middle atmosphere.Key words. Atmospheric composition and structure (middle atmosphere · composition and chemistry) · Meteorology and atmospheric dynamics (middle atmosphere dynamics).

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