PCA and vTEC climatology at midnight over mid-latitude regions

The effect of the thermospheric vertical neutral wind on vertical total electron content (vTEC) variations including longitudinal anomaly, remaining winter anomaly, mid-latitude summer night anomaly, and semiannual anomaly is studied at mid-latitude regions around zero magnetic declination at midnig...

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Autores principales: Natali, María Paula, Meza, Amalia Margarita
Formato: Articulo
Lenguaje:Inglés
Publicado: 2017
Materias:
Ciencias Astronómicas
Longitude difference of vTEC
Mid-latitude ionosphere
Neutral wind
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/87226
Aporte de:
SEDICI (UNLP) de Universidad Nacional de La Plata
id I19-R120-10915-87226
record_format dspace
institution Universidad Nacional de La Plata
institution_str I-19
repository_str R-120
collection SEDICI (UNLP)
language Inglés
topic Ciencias Astronómicas
Longitude difference of vTEC
Mid-latitude ionosphere
Neutral wind
spellingShingle Ciencias Astronómicas
Longitude difference of vTEC
Mid-latitude ionosphere
Neutral wind
Natali, María Paula
Meza, Amalia Margarita
PCA and vTEC climatology at midnight over mid-latitude regions
topic_facet Ciencias Astronómicas
Longitude difference of vTEC
Mid-latitude ionosphere
Neutral wind
description The effect of the thermospheric vertical neutral wind on vertical total electron content (vTEC) variations including longitudinal anomaly, remaining winter anomaly, mid-latitude summer night anomaly, and semiannual anomaly is studied at mid-latitude regions around zero magnetic declination at midnight during high solar activity. By using the principal component analysis (PCA) numerical technique, this work studies the spatial and temporal variations of the ionosphere at midnight over mid-latitude regions during 2000–2002. PCA is applied to a time series of global vTEC maps produced by the International Global Navigation Satellite System (GNSS) Service. Four regions were studied in particular, each located at mid-latitude and approximately centered at zero magnetic declination, with two in the northern hemisphere and two in southern hemisphere, and all are located near and far from geomagnetic poles in each case. This technique provides an effective method to analyze the main ionospheric variabilities at mid-latitudes. PCA is also applied to the vTEC computed using the International Reference Ionosphere (IRI) 2012 model, to analyze the capability of this model to represent ionospheric variabilities at mid-latitude. Also, the Horizontal Wind Model 2007 (HWM07) is used to improve our climatology interpretation, by analyzing the relationship between vTEC and thermospheric wind, both quantitatively and qualitatively. At midnight, the behavior of mean vTEC values strongly responds to vertical wind variation, experiencing a decrease of about 10–15% with the action of the positive vertical component of the field-aligned neutral wind lasting for 2 h in all regions except for Oceania. Notable results include: a significant increase toward higher latitudes during summer in the South America and Asia regions, associated with the mid-latitude summer night anomaly, and an increase toward higher latitudes in winter in the North America and Oceania regions, highlighting the remnant effect of the winter anomaly. Finally, the longitudinal variations of east–west differences, named longitudinal anomaly, show maximum values in March for North America, in December for South America and Oceania, and are not shown for Asia. Our results show that at mid-latitudes regions, the IRI model represents midnight ionospheric mean values with a similar spatial distribution, but the values are always lower than those obtained by GNSS. The differences between IRI and GNSS results include: the longitudinal anomaly is characterized by a stronger semiannual variation in both North America and South America, with a maximum in the equinoxes, while for the Asian region, the behavior is almost constant throughout the years, and finally, there is an absence of the winter anomaly remnant.
format Articulo
Articulo
author Natali, María Paula
Meza, Amalia Margarita
author_facet Natali, María Paula
Meza, Amalia Margarita
author_sort Natali, María Paula
title PCA and vTEC climatology at midnight over mid-latitude regions
title_short PCA and vTEC climatology at midnight over mid-latitude regions
title_full PCA and vTEC climatology at midnight over mid-latitude regions
title_fullStr PCA and vTEC climatology at midnight over mid-latitude regions
title_full_unstemmed PCA and vTEC climatology at midnight over mid-latitude regions
title_sort pca and vtec climatology at midnight over mid-latitude regions
publishDate 2017
url http://sedici.unlp.edu.ar/handle/10915/87226
work_keys_str_mv AT natalimariapaula pcaandvtecclimatologyatmidnightovermidlatituderegions
AT mezaamaliamargarita pcaandvtecclimatologyatmidnightovermidlatituderegions
bdutipo_str Repositorios
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