scholarly journals The intensification of metallic layered phenomena above thunderstorms through the modulation of atmospheric tides

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Bingkun Yu ◽  
Xianghui Xue ◽  
Chengling Kuo ◽  
Gaopeng Lu ◽  
Christopher J. Scott ◽  
...  
Keyword(s):  
Lower Ionosphere ◽  
Atmospheric Tides ◽  
Metallic Ions ◽  
Number Density ◽  
Mesopause Region ◽  
Lidar Observation ◽  
Metal Atoms ◽  
Chemical Coupling ◽  
Coupling Processes ◽  
Neutral Metal

AbstractWe present a multi-instrument experiment to study the effects of tropospheric thunderstorms on the mesopause region and the lower ionosphere. Sodium (Na) lidar and ionospheric observations by two digital ionospheric sounders are used to study the variation in the neutral metal atoms and metallic ions above thunderstorms. An enhanced ionospheric sporadic E layer with a downward tidal phase is observed followed by a subsequent intensification of neutral Na number density with an increase of 600 cm−3 in the mesosphere. In addition, the Na neutral chemistry and ion-molecule chemistry are considered in a Na chemistry model to simulate the dynamical and chemical coupling processes in the mesosphere and ionosphere above thunderstorms. The enhanced Na layer in the simulation obtained by using the ionospheric observation as input is in agreement with the Na lidar observation. We find that the intensification of metallic layered phenomena above thunderstorms is associated with the atmospheric tides, as a result of the troposphere-mesosphere-ionosphere coupling.

scholarly journals The intensification of metallic layered phenomena above thunderstorms through the modulation of atmospheric tides

2018 ◽  
Author(s):  
Bingkun Yu ◽  
Xianghui Xue ◽  
Chengling Kuo ◽  
Gaopeng Lu ◽  
Xiankang Dou ◽  
...  
Keyword(s):  
Lower Ionosphere ◽  
Atmospheric Tides ◽  
Metallic Ions ◽  
Mesopause Region ◽  
Lidar Observation ◽  
Chemical Coupling ◽  
Sporadic E Layer ◽  
Sporadic E ◽  
Coupling Processes ◽  
Neutral Metal

Abstract. We present a multi-instrument experiment to study the effects of tropospheric thunderstorms on the mesopause region and the lower ionosphere. The sodium (Na) lidar observation and the ionospheric observation by two digital ionospheric sounders are used to study the variation of the neutral metal atoms and metallic ions above thunderstorms. The enhanced ionospheric sporadic E layer with a downward tidal phase is observed followed by a subsequent intensification of neutral Na density with an increase of 600 cm−3 in the mesosphere. In addition, the Na neutral chemistry and ion-molecule chemistry reactions are considered in the Na chemistry model to simulate the dynamical and chemical coupling processes in the mesosphere and ionosphere above thunderstorms. The enhanced Na layer in the simulation using the ionospheric observation as input is in agreement with the Na lidar observation. We find that the intensification of metallic layered phenomena above thunderstorms is associated with the atmospheric tides, as a result of the troposphere-mesosphere-ionosphere coupling.

scholarly journals First simulations of day-to-day variability of mid-latitude sporadic E layer structures

2020 ◽  
Vol 72 (1) ◽  
Author(s):  
Satoshi Andoh ◽  
Akinori Saito ◽  
Hiroyuki Shinagawa ◽  
Mitsumu K. Ejiri
Keyword(s):  
Three Dimensional ◽  
Lower Ionosphere ◽  
Atmospheric Tides ◽  
Ionospheric Model ◽  
Radio Waves ◽  
Metallic Ions ◽  
Long Distance ◽  
Distance Communication ◽  
Sporadic E ◽  
Realistic Information

Abstract We present the first simulations that successfully reproduce the day-to-day variability of the mid-latitude sporadic E ($$E_s$$ E s ) layers. $$E_s$$ E s layers appearing in the lower ionosphere have been extensively investigated to monitor and forecast their effects on long-distance communication by radio waves. Although it is widely accepted that the atmospheric tides are important in generating the $$E_s$$ E s layers, no simulations to date have reproduced the $$E_s$$ E s layers observed on a certain day. This is due to the lack of the combination of realistic information on the atmospheric tides in the lower ionosphere and a three-dimensional numerical ionospheric model that can simulate the precise transport of metallic ions. We developed a numerical ionospheric model coupled with the neutral winds from the GAIA (Ground-to-topside model of Atmosphere and Ionosphere for Aeronomy). The fundamental structures and the day-to-day variations of the $$E_s$$ E s layers observed by a $$\hbox {Ca}^+$$ Ca + lidar are well-reproduced in the simulations.

scholarly journals Contribution of meteor flux in the occurrence of sporadic-E (Es) layers over the Arabian Peninsula

2021 ◽  
Vol 39 (3) ◽  
pp. 471-478
Author(s):  
Muhammad Mubasshir Shaikh ◽  
Govardan Gopakumar ◽  
Aisha Abdulla Al-owais ◽  
Maryam Essa Sharif ◽  
Ilias Fernini
Keyword(s):  
Layered Structure ◽  
Arabian Peninsula ◽  
Lower Ionosphere ◽  
Early Summer ◽  
Upper Atmosphere ◽  
Metallic Ions ◽  
Metal Atoms ◽  
Sporadic E ◽  
Using Data ◽  
Free Metal

Abstract. A sporadic-E (Es) layer is generally associated with a thin-layered structure present in the lower ionosphere, mostly consisting of metallic ions. This metallic ion layer is formed when meteors burn in the upper atmosphere, resulting in the deposition of free metal atoms and ions. Many studies have attributed the presence of the Es layer to the metallic ion layer, specifically when the layer is observed during the nighttime. Using data from a network of meteor monitoring towers and a collocated digital ionosonde radar near the Arabian Peninsula, in this paper, we report our observations of Es layer occurrences together with the meteor count. The trend of monthly averages of Es layer intensity shows a maximum in late spring and early summer months and a minimum in winter months, whereas the meteor counts were highest in winter months and lowest in spring and early summer months. This shows that the presence of the Es layer and the meteor counts have no correlation in time, both diurnally and seasonally. This leads us to conclude that the presence of meteors is not the main cause of the presence of the Es layer over the Arabian Peninsula.

scholarly journals Contribution of Meteor Flux in the Occurrence of Sporadic-E over Arabian Peninsula

2020 ◽  
Author(s):  
Muhammad Mubasshir Shaikh ◽  
Govardan Gopakumar ◽  
Aisha Abdulla Alowais ◽  
Maryam Essa Sharif ◽  
Ilias Fernini
Keyword(s):  
Layered Structure ◽  
Count Data ◽  
Arabian Peninsula ◽  
Lower Ionosphere ◽  
Upper Atmosphere ◽  
Metallic Ions ◽  
Metal Atoms ◽  
Sporadic E ◽  
Using Data ◽  
Free Metal

Abstract. Sporadic-E (Es) is generally associated with a thin-layered structure present in the lower ionosphere mostly consisted of metallic ions. This metallic ion layer is formed when meteors burn in the upper atmosphere resulting in the deposition of free metal atoms and ions. Many studies have attributed to the presence of Es due to metallic ion layer, specifically during the nighttime. Using data from a network of meteor monitoring towers and a collocated digital ionosonde radar near Arabian Peninsula, in this paper, we are reporting our observations of Es together with the meteor count. It has been observed that the presence of Es and the meteor count data have no correlation in time, both diurnally and seasonally, leading us to conclude that presence of meteors is not the main cause for the presence of Es over Arabian Peninsula.

scholarly journals Experimental measurements of the permeability characteristics of rare earth ore under the hydro-chemical coupling effect

RSC Advances ◽  
2018 ◽  
Vol 8 (21) ◽  
pp. 11652-11660 ◽  
Author(s):  
Xiaojun Wang ◽  
Yulong Zhuo ◽  
Kui Zhao ◽  
Wen Zhong
Keyword(s):  
Rare Earth ◽  
Coupling Effect ◽  
Experimental Measurements ◽  
Permeability Characteristics ◽  
Leaching Process ◽  
Chemical Coupling ◽  
Coupling Processes

Two coupling processes—solution seepage and chemical replacement—occur in the in situ leaching process of ion-absorbed-rare-earth ore.

scholarly journals Influence of water vapour on the height distribution of positive ions, effective recombination coefficient and ionisation balance in the quiet lower ionosphere

2014 ◽  
Vol 32 (3) ◽  
pp. 207-222 ◽  
Author(s):  
V. Barabash ◽  
A. Osepian ◽  
P. Dalin
Keyword(s):  
Water Vapour ◽  
Electron Density ◽  
Electron Number Density ◽  
Lower Ionosphere ◽  
Recombination Coefficient ◽  
Height Distribution ◽  
Number Density ◽  
Electron Number ◽  
Water Vapour Concentration ◽  
Vapour Concentration

Abstract. Mesospheric water vapour concentration effects on the ion composition and electron density in the lower ionosphere under quiet geophysical conditions were examined. Water vapour is an important compound in the mesosphere and the lower thermosphere that affects ion composition due to hydrogen radical production and consequently modifies the electron number density. Recent lower-ionosphere investigations have primarily concentrated on the geomagnetic disturbance periods. Meanwhile, studies on the electron density under quiet conditions are quite rare. The goal of this study is to contribute to a better understanding of the ionospheric parameter responses to water vapour variability in the quiet lower ionosphere. By applying a numerical D region ion chemistry model, we evaluated efficiencies for the channels forming hydrated cluster ions from the NO+ and O2+ primary ions (i.e. NO+.H2O and O2+.H2O, respectively), and the channel forming H+(H2O)n proton hydrates from water clusters at different altitudes using profiles with low and high water vapour concentrations. Profiles for positive ions, effective recombination coefficients and electrons were modelled for three particular cases using electron density measurements obtained during rocket campaigns. It was found that the water vapour concentration variations in the mesosphere affect the position of both the Cl2+ proton hydrate layer upper border, comprising the NO+(H2O)n and O2+(H2O)n hydrated cluster ions, and the Cl1+ hydrate cluster layer lower border, comprising the H+(H2O)n pure proton hydrates, as well as the numerical cluster densities. The water variations caused large changes in the effective recombination coefficient and electron density between altitudes of 75 and 87 km. However, the effective recombination coefficient, αeff, and electron number density did not respond even to large water vapour concentration variations occurring at other altitudes in the mesosphere. We determined the water vapour concentration upper limit at altitudes between 75 and 87 km, beyond which the water vapour concentration ceases to influence the numerical densities of Cl2+ and Cl1+, the effective recombination coefficient and the electron number density in the summer ionosphere. This water vapour concentration limit corresponds to values found in the H2O-1 profile that was observed in the summer mesosphere by the Upper Atmosphere Research Satellite (UARS). The electron density modelled using the H2O-1 profile agreed well with the electron density measured in the summer ionosphere when the measured profiles did not have sharp gradients. For sharp gradients in electron and positive ion number densities, a water profile that can reproduce the characteristic behaviour of the ionospheric parameters should have an inhomogeneous height distribution of water vapour.

scholarly journals Electron density profiles in the quiet lower ionosphere based on the results of modeling and experimental data

2012 ◽  
Vol 30 (9) ◽  
pp. 1345-1360 ◽  
Author(s):  
V. Barabash ◽  
A. Osepian ◽  
P. Dalin ◽  
S. Kirkwood
Keyword(s):  
Solar Activity ◽  
Electron Density ◽  
Lower Ionosphere ◽  
Ionization Rate ◽  
Number Density ◽  
Density Profiles ◽  
Oxide Concentration ◽  
D Region ◽  
Nitric Oxide Concentration ◽  
Electron Density Profiles

Abstract. The theoretical PGI (Polar Geophysical Institute) model for the quiet lower ionosphere has been applied for computing the ionization rate and electron density profiles in the summer and winter D-region at solar zenith angles less than 80° and larger than 99° under steady state conditions. In order to minimize possible errors in estimation of ionization rates provided by solar electromagnetic radiation and to obtain the most exact values of electron density, each wavelength range of the solar spectrum has been divided into several intervals and the relations between the solar radiation intensity at these wavelengths and the solar activity index F10.7 have been incorporated into the model. Influence of minor neutral species (NO, H2O, O, O3) concentrations on the electron number density at different altitudes of the sunlit quiet D-region has been examined. The results demonstrate that at altitudes above 70 km, the modeled electron density is most sensitive to variations of nitric oxide concentration. Changes of water vapor concentration in the whole altitude range of the mesosphere influence the electron density only in the narrow height interval 73–85 km. The effect of the change of atomic oxygen and ozone concentration is the least significant and takes place only below 70 km. Model responses to changes of the solar zenith angle, solar activity (low–high) and season (summer–winter) have been considered. Modeled electron density profiles have been evaluated by comparison with experimental profiles available from the rocket measurements for the same conditions. It is demonstrated that the theoretical model for the quiet lower ionosphere is quite effective in describing variations in ionization rate, electron number density and effective recombination coefficient as functions of solar zenith angle, solar activity and season. The model may be used for solving inverse tasks, in particular, for estimations of nitric oxide concentration in the mesosphere.

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

2015 ◽  
Vol 33 (6) ◽  
pp. 749-767 ◽  
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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