Assessment of precision in ionospheric electron density profiles retrieved by GPS radio occultations

The Constellation Observing System for Meteorology Ionosphere and Climate (COSMIC) is a six satellite radio occultation mission that was launched in April 2006. The close proximity of these satellites during some months after launch provides a unique opportunity to evaluate the precision of Global P...

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Detalles Bibliográficos
Autor principal: Hierro, Rodrigo Federico
Publicado: 2014
Materias:
Electron density
GPS radio occultation
Uncertainties
Atmospheric electricity
Carrier concentration
E region
Electron density measurement
Global positioning system
Ionosphere
Radio
Constellation observing system for meteorology
Difference between lines
Electron density profiles
GPS radio occultations
Ionosphere and climates
Ionospheric electron densities
Simultaneous observation
Electrons
Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_02731177_v54_n11_p2249_Alexander
http://hdl.handle.net/20.500.12110/paper_02731177_v54_n11_p2249_Alexander
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id paper:paper_02731177_v54_n11_p2249_Alexander
record_format dspace
spelling paper:paper_02731177_v54_n11_p2249_Alexander2023-06-08T15:25:43Z Assessment of precision in ionospheric electron density profiles retrieved by GPS radio occultations Hierro, Rodrigo Federico Electron density GPS radio occultation Uncertainties Atmospheric electricity Carrier concentration E region Electron density measurement Global positioning system Ionosphere Radio Constellation observing system for meteorology Difference between lines Electron density profiles GPS radio occultations Ionosphere and climates Ionospheric electron densities Simultaneous observation Uncertainties Electrons The Constellation Observing System for Meteorology Ionosphere and Climate (COSMIC) is a six satellite radio occultation mission that was launched in April 2006. The close proximity of these satellites during some months after launch provides a unique opportunity to evaluate the precision of Global Positioning System (GPS) radio occultation (RO) retrievals of ionospheric electron density from nearly collocated and simultaneous observations. RO data from 30 consecutive days during July and August 2006 are divided into ten groups in terms of daytime or nighttime and latitude. In all cases, the best precision values (about 1%) are found at the F peak height and they slightly degrade upwards. For all daytime groups, it is seen that electron density profiles above about 120 km height exhibit a substantial improvement in precision. Nighttime groups are rather diverse: in particular, the precision becomes better than 10% above different levels between 120 and 200 km height. Our overall results show that up to 100-200 km (depending on each group), the uncertainty associated with the precision is in the order of the measured electron density values. Even worse, the retrieved values tend sometimes to be negative. Although we cannot rely directly on electron density values at these altitudes, the shape of the profiles could be indicative of some ionospheric features (e.g. waves and sporadic E layers). Above 200 km, the profiles of precision are qualitatively quite independent from daytime or latitude. From all the nearly collocated pairs studied, only 49 exhibited a difference between line of sight angles of both RO at the F peak height larger than 10°. After analyzing them we find no clear indications of a significant representativeness error in electron density profiles due to the spherical assumption above 120 km height. Differences in precision between setting and rising GPS RO may be attributed to the modification of the processing algorithms applied to rising cases during the initial period of the COSMIC mission. © 2014 COSPAR. Published by Elsevier Ltd. All rights reserved. Fil:Hierro, R. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 2014 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_02731177_v54_n11_p2249_Alexander http://hdl.handle.net/20.500.12110/paper_02731177_v54_n11_p2249_Alexander
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Electron density
GPS radio occultation
Uncertainties
Atmospheric electricity
Carrier concentration
E region
Electron density measurement
Global positioning system
Ionosphere
Radio
Constellation observing system for meteorology
Difference between lines
Electron density profiles
GPS radio occultations
Ionosphere and climates
Ionospheric electron densities
Simultaneous observation
Uncertainties
Electrons
spellingShingle Electron density
GPS radio occultation
Uncertainties
Atmospheric electricity
Carrier concentration
E region
Electron density measurement
Global positioning system
Ionosphere
Radio
Constellation observing system for meteorology
Difference between lines
Electron density profiles
GPS radio occultations
Ionosphere and climates
Ionospheric electron densities
Simultaneous observation
Uncertainties
Electrons
Hierro, Rodrigo Federico
Assessment of precision in ionospheric electron density profiles retrieved by GPS radio occultations
topic_facet Electron density
GPS radio occultation
Uncertainties
Atmospheric electricity
Carrier concentration
E region
Electron density measurement
Global positioning system
Ionosphere
Radio
Constellation observing system for meteorology
Difference between lines
Electron density profiles
GPS radio occultations
Ionosphere and climates
Ionospheric electron densities
Simultaneous observation
Uncertainties
Electrons
description The Constellation Observing System for Meteorology Ionosphere and Climate (COSMIC) is a six satellite radio occultation mission that was launched in April 2006. The close proximity of these satellites during some months after launch provides a unique opportunity to evaluate the precision of Global Positioning System (GPS) radio occultation (RO) retrievals of ionospheric electron density from nearly collocated and simultaneous observations. RO data from 30 consecutive days during July and August 2006 are divided into ten groups in terms of daytime or nighttime and latitude. In all cases, the best precision values (about 1%) are found at the F peak height and they slightly degrade upwards. For all daytime groups, it is seen that electron density profiles above about 120 km height exhibit a substantial improvement in precision. Nighttime groups are rather diverse: in particular, the precision becomes better than 10% above different levels between 120 and 200 km height. Our overall results show that up to 100-200 km (depending on each group), the uncertainty associated with the precision is in the order of the measured electron density values. Even worse, the retrieved values tend sometimes to be negative. Although we cannot rely directly on electron density values at these altitudes, the shape of the profiles could be indicative of some ionospheric features (e.g. waves and sporadic E layers). Above 200 km, the profiles of precision are qualitatively quite independent from daytime or latitude. From all the nearly collocated pairs studied, only 49 exhibited a difference between line of sight angles of both RO at the F peak height larger than 10°. After analyzing them we find no clear indications of a significant representativeness error in electron density profiles due to the spherical assumption above 120 km height. Differences in precision between setting and rising GPS RO may be attributed to the modification of the processing algorithms applied to rising cases during the initial period of the COSMIC mission. © 2014 COSPAR. Published by Elsevier Ltd. All rights reserved.
author Hierro, Rodrigo Federico
author_facet Hierro, Rodrigo Federico
author_sort Hierro, Rodrigo Federico
title Assessment of precision in ionospheric electron density profiles retrieved by GPS radio occultations
title_short Assessment of precision in ionospheric electron density profiles retrieved by GPS radio occultations
title_full Assessment of precision in ionospheric electron density profiles retrieved by GPS radio occultations
title_fullStr Assessment of precision in ionospheric electron density profiles retrieved by GPS radio occultations
title_full_unstemmed Assessment of precision in ionospheric electron density profiles retrieved by GPS radio occultations
title_sort assessment of precision in ionospheric electron density profiles retrieved by gps radio occultations
publishDate 2014
url https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_02731177_v54_n11_p2249_Alexander
http://hdl.handle.net/20.500.12110/paper_02731177_v54_n11_p2249_Alexander
work_keys_str_mv AT hierrorodrigofederico assessmentofprecisioninionosphericelectrondensityprofilesretrievedbygpsradiooccultations
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