scholarly journals Stratification of the Low-Latitude and Near-EquatorialF2Layer, Topside Ionization Ledge, andF3Layer: What We Know about This? A Review

2012 ◽  
Vol 2012 ◽  
pp. 1-22 ◽  
Author(s):  
M. V. Klimenko ◽  
B. Zhao ◽  
A. T. Karpachev ◽  
V. V. Klimenko
Keyword(s):  
Electric Field ◽  
Physical Mechanism ◽  
Equatorial Ionosphere ◽  
Layer Formation ◽  
Low Latitude ◽  
Meridional Component ◽  
Ionospheric Physics ◽  
Additional Layer ◽  
Plasma Diffusion ◽  
History Of

A large number of researches have been devoted to the formation of additional layers in theFregion of the equatorial ionosphere, first of which has been published in 1940s. Originally the occurrence of such layer was named “stratification of equatorialF2layer.” The additional layer was later named as theF3layer. The theoretical researches have shown that theF3layer is formed by zonal component of electric field with assistance of meridional component of thermospheric wind and field-aligned plasma diffusion. The physical mechanism of theF3layer formation is clearly formulated for the morning-noon period, although theF3layer is also observed at other hours. This paper presents a brief review into the history of the additional layer researches, describes the current progress of these researches, and identifies the most important problems in this field of the ionospheric physics.

scholarly journals Physical mechanism and statistics of occurrence of an additional layer in the equatorial ionosphere

1998 ◽  
Vol 103 (A12) ◽  
pp. 29169-29181 ◽  
Author(s):  
N. Balan ◽  
I. S. Batista ◽  
M. A. Abdu ◽  
J. MacDougall ◽  
G. J. Bailey
Keyword(s):  
Physical Mechanism ◽  
Equatorial Ionosphere ◽  
Additional Layer

Evidence for the geographic control of additional layer formation in the low-latitude ionosphere

2001 ◽  
Vol 27 (6-7) ◽  
pp. 1293-1297 ◽  
Author(s):  
C.C. Hsiao ◽  
J.Y. Liu ◽  
R.T. Tsunoda ◽  
S. Fukao ◽  
S. Saroso ◽  
...  
Keyword(s):  
Layer Formation ◽  
Low Latitude ◽  
Additional Layer ◽  
Low Latitude Ionosphere

scholarly journals Identification of the mechanisms responsible for anomalies in the tropical lower thermosphere/ionosphere caused by the January 2009 sudden stratospheric warming

2019 ◽  
Vol 9 ◽  
pp. A39 ◽  
Author(s):  
Maxim V. Klimenko ◽  
Vladimir V. Klimenko ◽  
Fedor S. Bessarab ◽  
Timofei V. Sukhodolov ◽  
Pavel A. Vasilev ◽  
...  
Keyword(s):  
Electric Field ◽  
Phase Change ◽  
Lower Thermosphere ◽  
Upper Atmosphere ◽  
Electron Content ◽  
Stratospheric Warming ◽  
Sudden Stratospheric Warming ◽  
Low Latitude ◽  
Plasma Drift ◽  
Solar Tide

We apply the Entire Atmosphere GLobal (EAGLE) model to investigate the upper atmosphere response to the January 2009 sudden stratospheric warming (SSW) event. The model successfully reproduces neutral temperature and total electron content (TEC) observations. Using both model and observational data, we identify a cooling in the tropical lower thermosphere caused by the SSW. This cooling affects the zonal electric field close to the equator, leading to an enhanced vertical plasma drift. We demonstrate that along with a SSW-related wind disturbance, which is the main source to form a dynamo electric field in the ionosphere, perturbations of the ionospheric conductivity also make a significant contribution to the formation of the electric field response to SSW. The post-sunset TEC enhancement and pre-sunrise electron content reduction are revealed as a response to the 2009 SSW. We show that at post-sunset hours the SSW affects low-latitude TEC via a disturbance of the meridional electric field. We also show that the phase change of the semidiurnal migrating solar tide (SW2) in the neutral wind caused by the 2009 SSW at the altitude of the dynamo electric field generation has a crucial importance for the SW2 phase change in the zonal electric field. Such changes lead to the appearance of anomalous diurnal variability of the equatorial electromagnetic plasma drift and subsequent low-latitudinal TEC disturbances in agreement with available observations. Plain Language Summary – Entire Atmosphere GLobal model (EAGLE) interactively calculates the troposphere, stratosphere, mesosphere, thermosphere, and plasmasphere–ionosphere system states and their response to various natural and anthropogenic forcing. In this paper, we study the upper atmosphere response to the major sudden stratospheric warming that occurred in January 2009. Our results agree well with the observed evolution of the neutral temperature in the upper atmosphere and with low-latitude ionospheric disturbances over America. For the first time, we identify an SSW-related cooling in the tropical lower thermosphere that, in turn, could provide additional information for understanding the mechanisms for the generation of electric field disturbances observed at low latitudes. We show that the SSW-related vertical electromagnetic drift due to electric field disturbances is a key mechanism for interpretation of an observed anomalous diurnal development of the equatorial ionization anomaly during the 2009 SSW event. We demonstrate that the link between thermospheric winds and the ionospheric dynamo electric field during the SSW is attained through the modulation of the semidiurnal migrating solar tide.

scholarly journals Three different types of electric field disturbances affecting equatorial ionosphere during a long‐duration prompt penetration event

2015 ◽  
Vol 120 (6) ◽  
pp. 4993-5008 ◽  
Author(s):  
D. Chakrabarty ◽  
Diptiranjan Rout ◽  
R. Sekar ◽  
R. Narayanan ◽  
G. D. Reeves ◽  
...  
Keyword(s):  
Electric Field ◽  
Equatorial Ionosphere ◽  
Long Duration ◽  
Different Types

Fossil flower of Staphylea L. from the Miocene amber of Mexico: New evidence of the Boreotropical Flora in low-latitude North America

2017 ◽  
Vol 108 (4) ◽  
pp. 471-478 ◽  
Author(s):  
Ana L. Hernández-Damián ◽  
Sergio R. S. Cevallos-Ferriz ◽  
Alma R. Huerta-Vergara
Keyword(s):  
North America ◽  
Northern Hemisphere ◽  
Fossil Record ◽  
First Record ◽  
High Latitudes ◽  
Low Latitude ◽  
Southern Mexico ◽  
Apparent Lack ◽  
History Of ◽  
New Evidence

ABSTRACTA new flower preserved in amber in sediments of Simojovel de Allende, México, is identified as an extinct member of Staphyleaceae, a family of angiosperms consisting of only three genera (Staphylea, Turpinia and Euscaphis), which has a large and abundant fossil record and is today distributed over the Northern Hemisphere. Staphylea ochoterenae sp. nov. is the first record of a flower for this group, which is small, pedicelled, pentamer, bisexual, with sepals and petals with similar size, dorsifixed anthers and superior ovary. Furthermore, the presence of stamens with pubescent filaments allows close comparison with extant flowers of Staphylea bulmada and S. forresti, species currently growing in Asia. However, their different number of style (one vs. three) and the apparent lack of a floral disc distinguish them from S. ochoterenae. The presence of Staphyleaceae in southern Mexico ca. 23 to 15My ago is evidence of the long history of integration of vegetation in low-latitude North America, in which some lineages, such as Staphylea, could move southwards from high latitudes of the Northern Hemisphere, as part of the Boreotropical Flora. In Mexico it grew in association with tropical elements, as suggested by the fossil record of the area.

scholarly journals Evidence for the interplanetary electric field effect on the OI 630.0 nm airglow over low latitude

2005 ◽  
Vol 110 (A11) ◽  
Author(s):  
D. Chakrabarty ◽  
R. Sekar ◽  
R. Narayanan ◽  
C. V. Devasia ◽  
B. M. Pathan
Keyword(s):  
Electric Field ◽  
Field Effect ◽  
Electric Field Effect ◽  
Low Latitude
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