Simulation of the coupling of the upper and lower atmosphere

The coupling of the upper and lower atmosphere and the problem of developing a unified numerical model of the Earth’s gaseous envelope is considered. The existing models of the upper and lower atmosphere are analyzed and specific models for use as parts of a future metamodels of Earth’s atmosphere are selected. A general algorithm for combining these models is proposed.     

LIDAR monitoring of the temperature in the middle and lower atmosphere

Two methods are described to monitor the temperature of the atmosphere from the ground to 100 km altitude. The Rayleigh LIDAR is now widely used (the French network includes four of those characteristics of which are given), and here, the major results obtained from this technique are presented. The second method, which completes the Rayleigh LIDAR downwards, uses the rotational Raman lines of O₂ and N₂. The method is briefly described and first results are presented. Including both the Rayleigh and Raman modes leads to a continuous temperature measuring method to survey changes in the lower and middle atmosphere.     

Breakdown characteristics of air in the lower atmosphere

This study is devoted to an analysis of the ionization and loss of electrons at early stages of discharge development in air at an altitude of 0–12 km. Ionization in an external electric field and background ionization, electron attachment and detachment from atomic and molecular oxygen, charge exchange, and negative ion conversion are considered. The dependence of the process rate constants on pressure is taken into account. It is demonstrated that the electric field at which effective air ionization begins decreases with increasing altitude.     

Disturbances of the upper atmosphere and ionosphere caused by acoustic-gravity wave sources in the lower atmosphere

The results of observations of acoustic-gravity waves in the troposphere and the ionosphere at middle latitudes during periods of passage of the solar terminator are presented. Tropospheric observations were performed using a lidar. The frequency characteristics of variations of the tropospheric parameters are determined based on observations of the intensity of the scattered lidar signal. The characteristics of variations of the total electron content (TEC) in the atmosphere are determined from data collected by GPS navigation satellites. An analysis of the observational data showed that the spectrum of variations of the atmospheric and ionospheric parameters is indicative of acoustic-gravity waves (AGW) propagating from the lower atmosphere. Modeling studies of the vertical propagation of AGW from the Earth’s surface showed that such waves quickly (within ~15 min) reach altitudes of the upper atmosphere (~300 km). The refraction and dissipation of waves in the upper atmosphere produces perturbations of the background state of the atmosphere and gives rise to the waveguide propagation of infrasonic wave components. The observed manifestations of TEC disturbances caused by AGW propagating from the lower atmosphere can be explained by the diurnal variation of the altitude of the ionosphere and the waveguide propagation of infrasonic waves.     

Perturbations in the composition of the atmosphere and temperature feedback

Summary A coupled radiative-photochemical, one-dimensional model is used to study effects of large perturbations in the concentration and distribution of CO₂ and O₃ in the Earth's atmosphere. The radiative part of the model includes the long-wave flux contributions due to O₃, CO₂ and H₂O. Large perturbations in the O₃ layer consequent to the production of NO _x during PCA events are considered. Interpretation of the results in terms of relaxation times shows that no instabilities due to extinction effects are observed. The effect on the ozone distribution of a doubling of CO₂ concentration is also reported. The climatic effect of such an increase (i.e. on the surface temperature) seems to depend on the amount of ozone in the atmosphere. Up to 20% increases in the ozone concentration are observed above 30 km. This behaviour is attributed to the decreased stratospheric temperature. The columnar density of ozone increases by 2.1%, which gives an additional surface temperature difference of 0.14 K.

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Riassunto Un modello unidimensionale radiativo-fotochimico è usato per studiare gli effetti di perturbazioni nella concentrazione e distribuzione di CO₂ e O₃ nell'atmosfera terrestre. La parte radiativa del modello include il contributo delle bande infrarosse di CO₂, O₃ e H₂O. Si considerano delle perturbazioni nello strato di ozono conseguenti a produzione di NO _x durante eventi di PCA. Questi risultati sono interpretati in termini di tempi di rilassamento e si dimostra che non insorgono instabilità dovute ad effetti di assorbimento. Si riporta anche l'effetto di un raddoppio della concentrazione di CO₂. L'effetto climatico di questo aumento (cioè sulla temperatura superficiale) dipende dalla quantità di ozono presente nell'atmosfera. Si hanno aumenti nella concentrazione di ozono fino al 20% al disopra di 30 km. Questo aumento è attribuito alla diminuzione della temperatura stratosferica. La densità colonnare dell'ozono aumenta del 2.1%, che aumenta ulteriormente la temperatura superficiale di 0.14 K.

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Резюме Радиационно-фотохимическая, одномерная модель используется для изучения влияния больших возмущений в концентрации и распределении CO₂ и O₃ в земной атмосфере. Радиационная часть модели включает вклады, обусловленные O₃, CO₂ и H₂O. Рассматриваются большие возмущения в слое O₃, получающемся в результате рождения NO _x в течение PCA событий. Интерпретация полученных результатов в терминах времен релаксации показывает, что не наблюдаются неустойчивости, обусловленные эффектами экстинкции. Также исследуется влияние на распределение озона удвоения концентрации CO₂. Климатический эффект такого увеличения (т.е. влияние на температуры поверхности), по-видимому, зависит от количества озона в атмосфере. Выше 30 км наблюдается увеличение концентрации озона до 20%. Такое поведение связано с уменьшением температуры стратосферы. Плотность озона увеличивается на величину 2.1%, что приводит к дополнительной разности температуры поверхности 0.14 К.

     

Hyperfine fields and magnetic coupling in Gd metal

New hyperfine field measurements on transition metal impurities in Gd are reported. The data cannot be explained on a simple RKKY model, but are consistent with a mechanism in which magnetic coupling is through the d electrons.     

On the superpropagator of fields with exponential coupling

We define the vacuum expectation value of the time-ordered product of two exponentials of free fields as a distribution using minimal singularity as a criterion. The implication of this definition for an exponentially self-coupled scalar field is studied in second order of a perturbation expansion.     

Small coupling (low temperature) expansions of nonabelian Yang-Mills fields on a lattice in temporal gauge

A systematic approach to large β expansions of nonabelian lattice gauge theories in temporal gauge is developed. The gauge fields are parameterized by a particular set of coordinates. The main problem is to define a regularization scheme for the infrared singularity that in this gauge appears in the Green's function in the infinite lattice limit. Comparison with exactly solvable two-dimensional models proves that regularization by subtraction of a naive translation invariant Green's function does not work. It suggests to use a Green's function of a half-space lattice first, to place the local observable in this lattice, and to let its distance from the lattice boundary tend to infinity at the end. This program is applied to the Wilson loop correlation function for the gauge group SU(2) which is calculated to second order in $\text{1}\text{β}$.     

A model regularizing gauge fields in the strong coupling region

We propose a model using an effective lagrangian for bilocal gauge extended fields, looking somehow as an average over all open strings with fixed end points. The locality of the action is retrieved as a range parameter, which acts as a regulator, shrinks, and the Yang-Mills theory is recovered in this limit. The system is invariant by rotation and translation, generalizes lattice gauge theories and allows regularized strong coupling expansions for Yang-Mills field theory.     

Measurement of excitation-contraction coupling time in lower extremities

Objective: The aim of this study was to apply a novel method to measure excitation-contraction coupling time (ECCT) in normal soleus muscles. Methods: We performed simultaneous recordings of soleus compound muscle action potential (CMAP) and foot movement-related potential (MRP), and measured ankle plantar flexion torque in 36 healthy subjects. We calculated ECCT and examined the relations between CMAP, MRP, ECCT and ankle plantar flexion torque. Results: Statistical analyses established reference ranges (mean ± SE) for CMAP (13.4 ± 0.9 mV), MRP (5.3 ± 0.4 m/s²), ECCT (5.2 ± 0.1 ms), torque (85.9 ± 6.4 Nm) and torque/body weight (1.4 ± 0.1 Nm/kg). The torque showed a positive linear correlation with CMAP (p = 0.041) and a negative linear correlation with ECCT (p = 0.045). Conclusion: Soleus ECCT can be recorded easily, and is useful to assess the impairment of E-C coupling in muscles of the lower extremities.     

Phase coupling gravitation: Symmetries and gauge fields

We consider possible generalizations of phase coupling gravitation, a relativistic theory introduced to account for the astrophysical missing mass problem in the framework of departures from newtonian gravitation. We show that pure phase coupled gravitation cannot be gauged. However, the theory can be extended by modifying the interactions. It is then endowed with a continuous global symmetry which can be gauged.     

Some aspects of the solar cyclicity display in the lower atmosphere of the Earth

Several examples of the solar cyclicity display in the lower atmosphere and in the ocean are considered using the North Atlantic as an illustration. The solar activity is manifested by the increased recurrence of certain circulation forms.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 39, No. 10, pp. 1342–1347, October, 1996.     

On the temperature of nonequilibrium optical fields

The dependence of the temperature of single-mode optical radiation on the relative dispersion of the number of photons is investigated. It is shown that the amplitude-stabilized field oscillator has a temperature twice as high as the oscillator excited by a heat source for the same mean energy. Further increase in the temperature of the stationary radiation field is possible by transition to nonclassical states not described by a positive definite quasi-probability function P().Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 6, pp. 7–13, June, 1972.     

Electric fields from model lightning discharges in a neutral atmosphere

The electric fields created by lightning discharges in a neutral atmosphere are calculated in the time representation. It is shown that asymmetric strokes containing horizontal currents can generate pronounced pulsed electric fields. A high-power quasistatic field can influence the middle atmosphere together with pulses. The motion of the current wave in a complex-geometry stroke channel can lead to an increase in the number of emitted pulses. At the periphery of the lightning cell, upon the arrival of the pulse, the electric field vector turns upward, to the stroke axis, and sideward. We also expect an increase in atmospheric turbulence due to convection at the frontal part of the cloud. The emerging inhomogeneities of the atmospheric temperature and density can facilitate the onset of plasma processes generated by the electric field of a strong thunderstorm. Since convection and the focusing electric fields are concentrated at the periphery, their joint action can lead to the appearance of circular and prolate luminous formations. Institute of Radiophysics and Electronics of the National Academy of Sciences, Khar’kov, Ukraine; The University of Electro-Communications, Tokyo, Japan. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 41, No. 6, pp. 699–722, June, 1998.     

Kondo coupling and Curie temperature of in the coherent potential approximation

The ferromagnetism of Ga_1-xMn_xAs is studied in the coherent potential approximation (CPA). In this work, we used the exact Hilbert transformation of the face-centered cubic (fcc) density of states (DOS), which is different from the usual semi-circle DOS employed in previous works. Using Weiss molecular theory, we obtained a nonlinear relation of Curie temperature with respect to Kondo coupling. Our calculated T_C agrees very well with measured values.     

Weather regimes and low-level temperature fields

Summary In the present paper we discuss weather regimes in the Northern Hemisphere, identified by means of the probability density distribution of an indicator of the planetary scale 850 mb eddy field during winter. We found that inter-regimes differences have behaviour similar to the one shown at the 500 mb geopotential height. We have speculated that at the upper tail of the distribution of the indicator there may be an additional mode representing a double global blocking flow. For this regime we found that significant features are present also in a sector encompassing the Mediterranean basin. Few speculations about the feasibility of limited-area forecast during inter-regime transition are offered.     

Gauge coupling unification,the GUT scale,and magic fields

We consider field sets that do not form complete SU(5) multiplets, but exactly preserve the one-loop MSSM prediction for α₃(MZ)${\alpha }_3(M_Z)$ independently of the value of their mass. Such fields can raise the unification scale in different ways, through a delayed convergence of the gauge couplings, a fake unified running below the GUT scale, or a postponed unification after a hoax crossing at a lower scale. The α₃(MZ)${\alpha }_3(M_Z)$ prediction is independent of the mass of the new fields, while the GUT scale often is not, which allows to vary the GUT scale. Such “magic” fields represent a useful tool in GUT model building. For example, they can be used to fix gauge coupling unification in certain two step breakings of the unified group, to suppress large KK thresholds in models with extra dimensions, or they can be interpreted as messengers of supersymmetry breaking in GMSB models.     

Remote sensing of thermal profile in the lower atmosphere by a radio-acoustic system

Summary A new radio-acoustic methodology, for the remote sensing of temperature profile in the lower troposphere, has been developed in the last few years. Since 1972 different types of radio-acoustic sounders have been designed and tested in the USA, Europe and Japan. The technique used for measurements in a Doppler tracking of a short acoustic pulse with a radar. Measurement of the sound speed as a function of delay from the start of the acoustic beam leads to the acquisition of the temperature vertical profile. After a brief review of the experimental radio-acoustic systems, the metric radio-acoustic sounder developed and tested at Istituto di Cosmogeofisica of the National Research Council (Italy) is analysed. Results of this sounder and its performance in fog-capping thermal inversion measurements are discussed. A comparison of the data measured with the radio-acoustic system and with traditional methods shows:a) sounder ability to produce vertical thermal profile with temperature accuracy and height discrimination comparable with conventional soundings;b) advantages typical of remote-sensing technique;c) applicability of the system both in assessing thermodynamic conditions in the planetary boundary layer (PBL) and in sensing conditions conductive to high concentrations of air pollutants at ground level. Preliminary results of the completely automatized system and application to air quality management are also presented. This work was partially supported by the Commission of the European Communities (CEC) under contract No. ENV·348 I(S) and by a research contract by ENEL-CRTN Milano.