scholarly journals On non-elliptic regions and solvability of balance equations for atmosphere dynamics

2007 ◽  
Vol 22 (3) ◽  
pp. 329-337
Author(s):  
Andrei Bourchtein ◽  
Ludmila Bourchtein
Keyword(s):  
Gravitational Waves ◽  
Southern Hemisphere ◽  
Numerical Schemes ◽  
Balance Equations ◽  
Tropical Zone ◽  
The Real ◽  
Modeling Systems ◽  
Great Amplitude ◽  
Real Atmosphere ◽  
Elliptic Regions

To eliminate the fast gravitational waves of great amplitude, which are not observed in the real atmosphere, the initial fields for numerical schemes of atmosphere forecasting and modeling systems are usually adjusted dynamically by applying balance relations. In this study we consider different forms of the balance equations and for each of them we detect the nonelliptic regions in the gridded atmosphere data of the Southern Hemisphere. The performed analysis reveals the geographical, vertical and zonally averaged distributions of nonelliptic regions with the most concentration in the tropical zone. The area of these regions is essentially smaller and less intensive for more complete and physically justified balance relations. The obtained results confirm the Kasaharas assumption that ellipticity conditions are violated in the actual atmospheric fields essentially due to approximations made under deriving the balance equations.

scholarly journals Unveiling the Nature of INTEGRAL Objects: a Review

2014 ◽  
Vol 1 (1) ◽  
pp. 240-245
Author(s):  
Pietro Parisi
Keyword(s):  
Ir Spectroscopy ◽  
Energy Range ◽  
Southern Hemisphere ◽  
Cross Correlation ◽  
Active Galaxies ◽  
X Ray ◽  
The Real ◽  
Real Nature ◽  
X Ray Binaries

Since its launch in October 2002, the <em>INTEGRAL</em> observatory has improved our knowledge of the hard X-ray sky above 20 keV, carrying out more than ten years of observations in the energy range from 5 keV to 8 MeV. The most recently published <em>INTEGRAL</em>/IBIS surveys listed more than seven hundred sources in the 20-100 keV band. Most of these objects are either Active Galaxies (AGNs) or X-ray binaries; a fraction of both classes is made of highly absorbed sources, often associated with dim optical counterparts. Despite the big eort in the identication process, a large part of these IBIS objects (~25% of them) still remains unclassied. Cross-correlation with archival catalogues and/or multiwaveband follow-up observations are of invaluable help to identify and properly classify this unknown objects, but only optical or IR spectroscopy with ground based telescopes in the Northern and Southern Hemisphere can reveal the real nature of these objects. In this work we report on source types that we nd among the unidentied objects in the most recent <em>INTEGRAL</em> surveys.

The development of ground based gravitational wave astronomy and opportunities for Australia–China collaboration

2015 ◽  
Vol 30 (28n29) ◽  
pp. 1545019
Author(s):  
David Blair ◽  
Li Ju ◽  
Chunnong Zhao ◽  
Linqing Wen ◽  
Qi Chu ◽  
...  
Keyword(s):  
Black Hole ◽  
Neutron Star ◽  
Gravitational Wave ◽  
Gravitational Waves ◽  
Southern Hemisphere ◽  
Event Rate ◽  
Wave Spectrum ◽  
Current Status ◽  
Dramatic Improvement ◽  
The Universe

This paper begins by reviewing the development of gravitational wave astronomy from the first predictions of gravitational waves to development of technologies across the entire gravitational wave spectrum, and then focuses on the current status of ground based gravitational wave detectors. With substantial improvements already demonstrated in early commissioning it is emphasised that Advanced detectors are on track for first detection of gravitational waves. The importance of a worldwide array of detectors is emphasised, and recent results are shown that demonstrate the continued advantage of a southern hemisphere detector. Finally it is shown that a north–south pair of 8 km arm length detectors would give rise to a dramatic improvement in event rate, enabling a pair of detectors to encompass a 64-times larger volume of the universe, to conduct a census on all stellar mass black hole mergers to [Formula: see text] and to observe neutron star mergers to a distance of [Formula: see text][Formula: see text]800 Mpc.

Kinetics of sulfuric acid-amine nucleation in the urban atmospheric environment

2020 ◽  
Author(s):  
Runlong Cai ◽  
Chao Yan ◽  
Jun Zheng ◽  
Lin Wang ◽  
Markku Kulmala ◽  
...  
Keyword(s):  
Reaction Kinetics ◽  
Urban Environment ◽  
Formation Rate ◽  
Particle Formation ◽  
Atmospheric Environment ◽  
Atmospheric Conditions ◽  
Laboratory Studies ◽  
New Particle Formation ◽  
The Real ◽  
Real Atmosphere

&lt;p&gt;The formation of new secondary aerosols form gaseous precursors is a frequent phenomenon in various atmospheric environments and it impacts aerosol number concentration, cloud formation, and hence climate. There has been a considerable number of new particle formation (NPF) studies in various atmospheric environments, but current knowledge on NPF in the polluted atmospheric boundary layer (e.g., the urban environment in megacities) is still limited. The clustering of H&lt;sub&gt;2&lt;/sub&gt;SO&lt;sub&gt;4&lt;/sub&gt; and amines is a possible mechanism driving the fast nucleation and initial growth of new particles in the polluted urban environment. Laboratory studies using typical ambient H&lt;sub&gt;2&lt;/sub&gt;SO&lt;sub&gt;4&lt;/sub&gt; concentrations and theoretical calculations based on quantum chemistry have provided insights into H&lt;sub&gt;2&lt;/sub&gt;SO&lt;sub&gt;4&lt;/sub&gt;-amine nucleation. However, the molecular-level mechanism and governing factors for H&lt;sub&gt;2&lt;/sub&gt;SO&lt;sub&gt;4&lt;/sub&gt;-amine nucleation have not been quantitatively investigated in the real atmosphere. Some previous studies indicate that differently from clean environments, the coagulation scavenging is a governing factor for NPF in polluted environments. In the presence of a high aerosol concentration in the polluted environment, a considerable fraction of the newly formed particles are scavenged by coagulation within minutes and hence, NPF is significantly suppressed. Similarly, the coagulation scavenging may also impact the steady-state cluster concentrations and the new particle formation rate. Due to the differences in the coagulation scavenging and perhaps some gaseous precursor concentrations between laboratory and atmospheric conditions, the reaction kinetics determined in previous laboratory studies may not directly applicable to the real atmosphere. Herein, based on long-term atmospheric measurements from January 2018 to March 2019 in urban Beijing, we show the different reaction kinetics under laboratory and atmospheric conditions and how to unify them using proper normalization approaches. The influences of governing factors on particle formation rate are then quantitatively elucidated. Based on the synergistic effects of these factors, an indicator for the occurrence of NPF in the urban environment is proposed and verified.&lt;/p&gt;

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