scholarly journals Sporadic E morphology based on COSMIC radio occultation data and its relationship with wind shear theory

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Jia Luo ◽  
Haifeng Liu ◽  
Xiaohua Xu
Keyword(s):  
Magnetic Field ◽  
Wind Shear ◽  
Radio Occultation ◽  
Field Model ◽  
Global Distribution ◽  
Cosmic Radio ◽  
Neutral Wind ◽  
Earth’S Magnetic Field ◽  
Low Altitude ◽  
Sporadic E

AbstractThe S4max data retrieved from the Constellation Observing System for the Meteorology, Ionosphere, and Climate (COSMIC) radio occultation (RO) measurements during 2007 to 2015 is adopted to investigate the global distribution and seasonal variation of the sporadic E (Es) layers in the present work. The long-term and short-term global Es occurrence maps are presented and the spatial and temporal distributions of Es occurrence rates (ORs) are further confirmed and studied. The International Geomagnetic Reference Field model (IGRF12) is used to calculate the horizontal intensity and inclination of the Earth’s magnetic field. The analysis shows that the Earth’s magnetic field is one of the fundamental reasons for the global distribution of the Es layers. In addition, the Horizontal Wind Field model HWM14 and the IGRF12 model were employed to calculate the vertical ion convergence (VIC) to examine the role of neutral wind shear in the global distribution of the Es ORs. The results reveal that the middle latitude distribution of simulated vertical concentration of Fe+ is similar to that of Es ORs, which indicates that the VIC induced by the neutral wind shear is an important factor in determining the geographical distribution, summer maximum (or winter minimum) and diurnal characteristics of Es ORs in middle latitudes. The new findings mainly include the following two aspects: (1) in summer over mid-latitudes, VIC peaks in the morning and afternoon to evening, which explains the semidiurnal behavior of Es ORs; (2) VIC reaches its minimum value in low-altitude (100 km) areas, which is the reason for the significant decrease in Es ORs in low-altitude areas. The disagreements between the VIC and Es ORs indicate that other processes, such as the meteor influx rate, the ionospheric electric fields and atmospheric tides, should also be considered as they may have an important impact on the variation of Es layers. Graphical Abstract

Global distribution of neutral wind shear associated with sporadic E layers derived from GAIA

2017 ◽  
Vol 122 (4) ◽  
pp. 4450-4465 ◽  
Author(s):  
H. Shinagawa ◽  
Y. Miyoshi ◽  
H. Jin ◽  
H. Fujiwara
Keyword(s):  
Wind Shear ◽  
Global Distribution ◽  
Neutral Wind ◽  
Sporadic E Layers ◽  
Sporadic E

scholarly journals Impact of Earth’s Magnetic Field Secular Drift on the Low-Altitude Proton Radiation Belt From 1900 to 2050

2019 ◽  
Vol 66 (7) ◽  
pp. 1746-1752
Author(s):  
S. Bourdarie ◽  
A. Fournier ◽  
A. Sicard ◽  
G. Hulot ◽  
J. Aubert ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Radiation Belt ◽  
Proton Radiation ◽  
Earth’S Magnetic Field ◽  
Earth's Magnetic Field ◽  
Low Altitude

scholarly journals Enhanced sporadic <i>E</i> occurrence rates during the Geminid meteor showers 2006–2010

2013 ◽  
Vol 11 ◽  
pp. 313-318 ◽  
Author(s):  
C. Jacobi ◽  
C. Arras ◽  
J. Wickert
Keyword(s):  
Northern Hemisphere ◽  
Strong Correlation ◽  
Wind Shear ◽  
Radio Occultation ◽  
Semidiurnal Tide ◽  
Metallic Ions ◽  
Meteor Radar ◽  
Meteor Showers ◽  
Short Delay ◽  
Sporadic E

Abstract. Northern Hemisphere midlatitude sporadic E (Es) layer occurrence rates derived from FORMOSAT-3/COSMIC GPS radio occultation (RO) measurements during the Geminid meteor showers 2006–2010 are compared with meteor rates obtained with the Collm (51.3° N, 13.0° E) VHF meteor radar. In most years, Es rates increase after the shower, with a short delay of few days. This indicates a possible link between meteor influx and the production of metallic ions that may form Es. There is an indication that the increase propagates downward, probably partly caused by tidal wind shear. However, the correlation between Es rates and meteor flux varies from year to year. A strong correlation is found especially in 2009, while in 2010 Es rates even decrease during the shower. This indicates that additional processes significantly influence Es occurrence also during meteor showers. A possible effect of the semidiurnal tide is found. During years with weaker tidal wind shear, the correlation between Es and meteor rates is even weaker.

Longitude Effect in Temperate Zone Sporadic E and the Earth's Magnetic Field

Nature ◽  
1960 ◽  
Vol 187 (4738) ◽  
pp. 676-677 ◽  
Author(s):  
L. H. HEISLER ◽  
J. D. WHITEHEAD
Keyword(s):  
Magnetic Field ◽  
Temperate Zone ◽  
Earth’S Magnetic Field ◽  
Earth's Magnetic Field ◽  
Sporadic E

scholarly journals The archaeomagnetic field recorded in ancient kiln walls in Si Satchanalai, Sukhothai

2021 ◽  
Vol 2145 (1) ◽  
pp. 012049
Author(s):  
R Supakulopas
Keyword(s):  
Magnetic Field ◽  
Confidence Limit ◽  
Field Model ◽  
Luminescence Dating ◽  
Human History ◽  
Earth’S Magnetic Field ◽  
Argon Dating ◽  
Dating Methods ◽  
Earth's Magnetic Field ◽  
The Mean

Abstract Archaeological dating is crucial in archaeology as it is a key to understand human history. However, traditional dating methods used by archaeologists such as potassium-argon dating and luminescence dating can provide ambiguous age results, e.g., argon loss during the dating returns young apparent ages. Therefore, I plan to establish an archaeomagnetic secular variation (ASV) curve to resolve this problem and use the ASV curve as an alternative tool to date archaeological artefacts. However, archaeomagnetic data in Thailand are absent from literature. Therefore, the ASV curve cannot be constructed from the archaeomagnetic data for this locality. To provide archaeomagnetic data to construct the ASV curve, the directions of the Earth’s magnetic field recorded in kiln walls from Ban Ko Noi (KN123, age 1,370 ± 100 A.D.), Si Satchanalai were measured. The mean declination and inclination of 49.6° and 32.6° with 95% confidence limit of 5.4° were determined from 10 samples from kiln KN123. Mean directions from this study were also compared with the directions of the Earth’s magnetic field in Thailand during 1,370 A.D. from the global archaeomagnetic field model ARCH3k.1. Declination and inclination from this study show significant departure from the field predicted by the ARCH3k.1 model.

scholarly journals Tidal wind shear observed by meteor radar and comparison with sporadic E occurrence rates based on GPS radio occultation observations

2019 ◽  
Vol 17 ◽  
pp. 213-224
Author(s):  
Christoph Jacobi ◽  
Christina Arras
Keyword(s):  
Wind Shear ◽  
Radio Occultation ◽  
Signal To Noise Ratio ◽  
Lower Thermosphere ◽  
Horizontal Component ◽  
Meteor Radar ◽  
Good Correspondence ◽  
Gps Radio Occultation ◽  
Middle Latitudes ◽  
Sporadic E

Abstract. We analyze tidal (diurnal, semidiurnal, terdiurnal, quarterdiurnal) phases and related wind shear in the mesosphere/lower thermosphere as observed by meteor radar over Collm (51.3∘ N, 13.0∘ E). The wind shear phases are compared with those of sporadic E (Es) occurrence rates, which were derived from GPS radio occultation signal-to-noise ratio (SNR) profiles measured by the COSMIC/FORMOSAT-3 satellites. At middle latitudes Es are mainly produced by wind shear, which, in the presence of a horizontal component of the Earth's magnetic field, leads to ion convergence in the region where the wind shear is negative. Consequently, we find good correspondence between radar derived wind shear and Es phases for the semidiurnal, terdiurnal, and quarterdiurnal tidal components. The diurnal tidal wind shear, however, does not correspond to the Es diurnal signal.

Tidal signatures in sporadic E occurrence rates - migrating and nonmigrating components, and comparison with neutral wind shear

2021 ◽  
Author(s):  
Christoph Jacobi ◽  
Kanykei Kandieva ◽  
Christina Arras
Keyword(s):  
Wind Shear ◽  
Signal To Noise Ratio ◽  
Ion Concentration ◽  
Vertical Shear ◽  
Neutral Wind ◽  
High Electron ◽  
Phase Measurements ◽  
Middle Latitudes ◽  
E Region ◽  
Sporadic E

&lt;p&gt;In the lower ionospheric E region, shallow regions of high electron density are found, which are called sporadic E (ES) layers. ES layers consist of thin clouds of accumulated ions. They occur mainly at middle latitudes, and they are most frequently found during the summer season. ES are generally formed at heights between 90 and 120 km. At midlatitudes, their occurrence can be described through the wind shear theory. According to this theory, ES formation is due to interaction between the metallic ion concentration, the Earth&amp;#8217;s magnetic field, and the vertical shear of the neutral wind. Here, we analyze ES occurrence rates (OR) obtained from ionospheric radio occultation measurements by the FORMOSAT-3/COSMIC constellation. To derive information on ES from RO, we use the Signal-to-Noise ratio (SNR) profiles of the GPS L1 phase measurements. If large SNR standard deviation values occur that are concentrated within a layer of less than 10 km thickness, we assume that the respective SNR profile disturbance is owing to an ES layer.&lt;/p&gt;&lt;p&gt;Midlatitude ES are found to be mainly connected with a migrating diurnal and semidiurnal component. Especially at high latitudes of the southern hemisphere, nonmigrating components such as a diurnal westward wave 2 and a semidiurnal westward wave 1 are also visible. Near the equator, a strong diurnal eastward wavenumber 3 component and a semidiurnal eastward wavenumber 2 component are found in summer and autumn. Terdiurnal and quarterdiurnal components are weaker than the diurnal and semidiurnal ones. We discuss seasonal and global distributions of migrating and nonmigrating components, and their relation to neutral wind shear derived from ground-based observations and numerical modeling.&lt;/p&gt;

Sign in / Sign up

Export Citation Format

Share Document