scholarly journals Attribution of the Principal Components of the Summertime Ozone Valley in the Upper Troposphere and Lower Stratosphere

2021 ◽  
Vol 8 ◽  
Author(s):  
Shujie Chang ◽  
Chunhua Shi ◽  
Dong Guo ◽  
Jianjun Xu
Keyword(s):  
Principal Components ◽  
Middle Latitude ◽  
Composite Analysis ◽  
Tropopause Height ◽  
The South ◽  
Low Latitude ◽  
Factors Affecting ◽  
Upper Troposphere ◽  
Latitude Region ◽  
East West

The key factors affecting the variation of the ‘ozone valley’, which appears during the boreal summer in the upper troposphere and lower stratosphere (UTLS) over the South Asian High (SAH) and its adjacent areas, have not been determined. This study has performed statistical analysis to improve the understanding of the roles of the sea surface temperature (SST), tropopause height, and the West Pacific Subtropical High (WPSH) on the ozone valley. Based on the European Center for Medium-Range Weather Forecasts Interim Re-Analysis (ERA5), Modern Era Retrospective Analysis for Research and Applications dataset version 2 (MERRA2), and the Stratospheric Water and Ozone Satellite Homogenized (SWOOSH) observation dataset, we examined the principal components of the zonal deviation of the total column ozone (TCO*) in the UTLS by applying the empirical orthogonal function (EOF), Liang-Kleeman information flow method, regression analysis, and composite analysis. The variations of the TCO* anomalies show three dominant modes, namely the east-west dipole mode in the low latitude region, the east-west tripole mode in the middle latitude region, and the south-north mode. According to the regression analysis and information flow, the three leading principal components of TCO* variations are related to the SST near Indonesia and the western Pacific Ocean in low latitudes, the tropopause height over the Iranian Plateau (IP), and the strength of the SAH over the eastern part of the Tibetan Plateau (TP), which is linked to the synchronousness between the SAH and the WPSH. For the east-west dipole mode in the low latitude region, composite analysis shows the interaction between the atmosphere and ocean causes the strengthening of the southern trough at 850 hPa and the divergence at 200 hPa, resulting in a decrease of the TCO* in the UTLS near the low latitude region around the TP. For the east-west tripole mode in the middle latitude region, the composite analysis shows obvious negative anomalies over the IP, where the TCO* reduces and the extent of the ozone valley over the IP increases with the rise of the tropopause. Comparatively, the south-north mode shows obvious positive anomalies over the TP, where the TCO* increases and the extent of the ozone valley over the TP decreases with a weak SAH. This mode is closely related to the location of the WPSH. In summary, the leading factors affecting the three dominant modes for the variations of the TCO* anomalies are SST, tropopause height, and the WPSH.

scholarly journals Statistical correlation of spectral broadening in VLF transmitter signal and low-frequency ionospheric turbulence from observation on DEMETER satellite

2008 ◽  
Vol 8 (5) ◽  
pp. 1105-1111 ◽  
Author(s):  
A. Rozhnoi ◽  
M. Solovieva ◽  
O. Molchanov ◽  
O. Akentieva ◽  
J. J. Berthelier ◽  
...  
Keyword(s):  
Middle Latitude ◽  
Statistical Correlation ◽  
Occurrence Rate ◽  
Signal Spectrum ◽  
Ionospheric Turbulence ◽  
Low Latitude ◽  
Demeter Satellite ◽  
Ion Cyclotron ◽  
Latitude Region

Abstract. In our earlier papers we have found the effect of VLF transmitter signal depression over epicenters of the large earthquakes from observation on the French DEMETER satellite that can be considered as new method of global diagnostics of seismic influence on the ionosphere. At present paper we investigate a possibility VLF signal-ionospheric turbulence interaction using additional characteristic of VLF signal-spectrum broadening. This characteristic is important for estimation of the interaction type: linear or nonlinear scattering. Our main results are the following: – There are two zones of increased spectrum broadening, which are centered near magnetic latitudes Φ=±10° and Φ=±40°. Basing on the previous case study research and ground ionosonde registrations, probably it is evidence of nonlinear (active) scattering of VLF signal on the ionospheric turbulence. However occurrence rate of spectrum broadening in the middle-latitude area is higher than in the near-equatorial zone (~15–20% in comparison with ~100% in former area) that is probably coincides with the rate of ionospheric turbulence. – From two years statistics of observation in the selected 3 low-latitude regions and 1 middle-latitude region inside reception area of VLF signal from NWC transmitter we find a correlation of spectrum broadening neither with ion-cyclotron noise (f=150–500 Hz), which possibly means poor representation of the turbulence by the noise due to its mixture with natural ELF emission (which correlates with whistler), nor with magnetic storm activity. – We find rather evident correlation of ion-cyclotron frequency noise, VLF signal depression and weak correlation of spectrum broadening with seismicity in the middle-latitude region over Japan. But in the low-latitude regions we do not find such a correlation. Statistical decrease of VLF signal supports our previous case study results. However rather weak spectrum broadening-seismicity statistical correlation means probably that passive scattering prevails upon nonlinear (active) one.

scholarly journals Investigation on the characteristics of the South Atlantic Anomaly

2021 ◽  
Author(s):  
Khairul Afifi Nasuddin ◽  
Mardina Abdullah ◽  
Nurul Shazana Abdul Hamid
Keyword(s):  
Magnetic Field ◽  
High Latitude ◽  
Geomagnetic Storms ◽  
Middle Latitude ◽  
South Atlantic ◽  
The South ◽  
Earth’S Magnetic Field ◽  
South Atlantic Anomaly ◽  
High Latitude Region ◽  
Latitude Region

Abstract. The South Atlantic Anomaly (SAA) is known for its weak Earth’s magnetic field strength. In this research, power spectrum analysis method was applied on the Horizontal intensity of the Earth’s magnetic field with data sample rate used at 1 min. Four active periods on 18 March 2012, 10 March 2012, 25 April 2012, and 30 June 2013 which represent the occurrence of geomagnetic storms and 4 normal periods on 25 March 2012, 21 March 2012, 4 April 2012, and 15 June 2013 which indicate no geomagnetic storm event were examined. Research was conducted by analyzing the SAA region where comparisons were made between the middle latitude region and the high latitude region. The results indicate that the SAA region tends to be persistent, and this may be due to the ring current. The middle latitude region experienced a mixture of persistent and antipersistent characteristics and this may be due to the transportation of plasma and seasonal weather variations. The high latitude region tends to be antipersistent. This may indicate that the high latitude region is influenced by geomagnetic storms and the aurora.

Borges the Post-Orientalist

2017 ◽  
Author(s):  
Robin Fiddian
Keyword(s):  
South Atlantic ◽  
Conclusive Evidence ◽  
Binary Opposition ◽  
The South ◽  
Civilization And Barbarism ◽  
The Stranger ◽  
East West

The chapter examines several works including ‘The East’, ‘A Thousand and One Nights’, and ‘Buddhism’, which are on subjects relating to the East, and finds conclusive evidence of a post-Orientalist optic in Borges’s writing at this point in his life. Japan inspires ‘The Stranger’ and ‘Nihon’, both included in The Limit and outstanding examples of Borges’s wit and craftsmanship. A comparison between ‘Nihon’ and ‘Story of the Warrior and the Captive Woman’ from an earlier collection illustrates Borges’s evolved approach to the binary opposition between civilization and barbarism, across the East–West divide. Two milongas are also studied in the context of the war in the South Atlantic (1982) and point to a disillusioned conclusion about Argentina 170 years on from formal independence in 1810.

scholarly journals A Case Study of Mass Transport during the East-West Oscillation of the Asian Summer Monsoon Anticyclone

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Jiali Luo ◽  
Jiayao Song ◽  
Hongying Tian ◽  
Lei Liu ◽  
Xinlei Liang
Keyword(s):  
Lower Stratosphere ◽  
Asian Summer Monsoon ◽  
Chemical Transport ◽  
Upward Motion ◽  
High Concentration ◽  
Upper Troposphere ◽  
Asian Summer ◽  
Mode Tm ◽  
East West

We use ERA-Interim reanalysis, MLS observations, and a trajectory model to examine the chemical transport and tracers distribution in the Upper Troposphere and Lower Stratosphere (UTLS) associated with an east-west oscillation case of the anticyclone in 2016. The results show that the spatial distribution of water vapor (H2O) was more consistent with the location of the anticyclone than carbon monoxide (CO) at 100 hPa, and an independent relative high concentration center was only found in H2O field. At 215 hPa, although the anticyclone center also migrated from the Tibetan Mode (TM) to the Iranian Mode (IM), the relative high concentration centers of both tracers were always colocated with regions where upward motion was strong in the UTLS. When the anticyclone migrated from the TM, air within the anticyclone over Tibetan Plateau may transport both westward and eastward but was always within the UTLS. The relative high concentration of tropospheric tracers within the anticyclone in the IM was from the east and transported by the westward propagation of the anticyclone rather than being lifted from surface directly. Air within the relative high geopotential height centers over Western Pacific was partly from the main anticyclone and partly from lower levels.

scholarly journals An Empirical Analysis of Factors Affecting Bank Interest Margins: Evidence from the South East European Countries

2018 ◽  
Vol 21 (2) ◽  
pp. 81-98
Author(s):  
Mehmed Ganić
Keyword(s):  
Interest Rate ◽  
Empirical Analysis ◽  
Banking Sector ◽  
Output Growth ◽  
The South ◽  
Factors Affecting ◽  
East European ◽  
Interest Margins ◽  
See Region ◽  
Bank Concentration

This paper provides an empirical analysis of factors affecting Bank Interest Margins in eight countries of the South‑East European (SEE) region between 2000 and 2014. The purpose of this paper is to examine and investigate the main drivers of Bank Interest Rate Margins across selected countries throughout the SEE region. Also, the study explored the relationship between the dependent variable Interest Rate Spread (IRS – as a proxy variable for measuring variation in Bank Interest Rate Margins) and a set of selected banks’ specific variables in SEE by employing panel data estimation methodology. This research is based on aggregate data for the whole banking sector of each country. In line with some expectations, our findings confirm the importance of credit risk, bank concentration operative efficiency, and inflation expectations in determining Bank Interest Rate Margins. Interestingly, in contrast to the majority of recent empirical research, the study found an inverse relationship between the bank concentration variable and Bank Interest Rate Margins as well as between the operational efficiency variable and Bank Interest Rate Margins. Also, the study could not find statistically significant evidence that Bank Interest Rate Margins are determined by output growth, bank profitability (measured by ROA) or liquidity risk.

scholarly journals Comparison of GPS TEC with IRI models of 2007, 2012, AND 1 2016 over Sukkur, Pakistan

2020 ◽  
Vol 1 (1) ◽  
pp. 1-10
Author(s):  
Adil Hussain ◽  
Munawar Shah
Keyword(s):  
Global Positioning System ◽  
Electron Content ◽  
Iri Model ◽  
Low Latitude ◽  
Total Electron ◽  
Gps Tec ◽  
Global Positioning ◽  
Radio Signals ◽  
Ionospheric Scintillations ◽  
Latitude Region

The international reference ionosphere (IRI) models have been widely used for correcting the ionospheric scintillations at different altitude levels. An evaluation on the performance of VTEC correction from IRI models (version 2007, 2012 and 2016) over Sukkur, Pakistan (27.71º N, 68.85º E) is presented in this work. Total Electron Content (TEC) from IRI models and GPS in 2019 over Sukkur region are compared. The main aim of this comparative analysis is to improve the VTEC in low latitude Sukkur, Pakistan. Moreover, this study will also help us to identify the credible IRI model for the correction of Global Positioning System (GPS) signal in low latitude region in future. The development of more accurate TEC finds useful applications in enhancing the extent to which ionospheric influences on radio signals are corrected. VTEC from GPS and IRI models are collected between May 1, 2019 and May 3, 2019. Additionally, Dst and Kp data are also compared in this work to estimate the geomagnetic storm variations. This study shows a good correlation of 0.83 between VTEC of GPS and IRI 2016. Furthermore, a correlation of 0.82 and 0.78 is also recorded for IRI 2012 and IRI 2007 respectively, with VTEC of GPS. The IRI TEC predictions and GPS-TEC measurements for the studied days reveal the potential of IRI model as a good candidate over Pakistan.

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