Application of seamless vertical profiles for use in the topside electron density modeling

2007 ◽  
Vol 39 (5) ◽  
pp. 774-778 ◽  
Author(s):  
L. Triskova ◽  
I. Galkin ◽  
V. Truhlik ◽  
B.W. Reinisch
Keyword(s):  
Electron Density ◽  
Vertical Profiles ◽  
Density Modeling

Electron Density Modeling of a Streamer Using LASCO Data of 2004 January and February

2006 ◽  
Vol 642 (1) ◽  
pp. 523-532 ◽  
Author(s):  
A. F. Thernisien ◽  
R. A. Howard
Keyword(s):  
Electron Density ◽  
Density Modeling

scholarly journals Empirical model of the ionosphere based on COSMIC/FORMOSAT-3 for neutral atmosphere radio occultation processing

2017 ◽  
Author(s):  
Miquel Garcia-Fernandez ◽  
Manuel Hernandez-Pajares ◽  
Antonio Rius ◽  
Riccardo Notarpietro ◽  
Axel von Engeln ◽  
...  
Keyword(s):  
Electron Density ◽  
Empirical Model ◽  
Radio Occultation ◽  
Scintillation Index ◽  
Neutral Atmosphere ◽  
Vertical Profiles ◽  
New Feature ◽  
Occultation Data ◽  
Relevant Level ◽  
Made In

Abstract. The Radio Occultation instrument at the upcoming EUMETSAT Polar System – Second Generation (EPS-SG) mission will be devoted primarily to monitor the neutral atmosphere through this payload, consisting of a GNSS receiver and occultation antennae pointing slightly below the Earth's limb. The resulting data will be processed by EUMETSAT (primarily for L1B data) and by the ROMSAF's Radio Occultation Processing Package (ROPP) software to obtain the vertical profiles of temperature, pressure and other relevant level 2 parameters of the neutral atmosphere. Newer versions of this software might include a feature by which empirical models of the ionosphere (i.e. vertical profiles of electron density) can be included in the processing in order to increase the accuracy of the inverted bending angle profiles. In order to test this new feature, this work includes the efforts that have been made in order to provide an empirical model of the ionosphere purely based on vertical profiles of electron density inverted from data of previous radio occultation (RO) missions (i.e. COSMIC/FORMOSAT-3). The methodology used in this work is based on using the separability hypothesis, to overcome the spherical symmetry assumption of the Abel inversion as well as a new mechanization of the inversion process, based on a joint processing of all the occultation data via a linear mean square filter, rather than adopting the classical peel onion approach. Additionally, with the development of this empirical model, efforts have been made to construct a proxy index for scintillation monitoring based on the inverted profiles (Occultation Scintillation Proxy Index or OSPI), which shows reasonable correlation with the amplitude scintillation index S4.

A new algorithm for improved ionospheric electron density modeling

1995 ◽  
Vol 22 (11) ◽  
pp. 1385-1388 ◽  
Author(s):  
P. G. Richards ◽  
D. G. Torr ◽  
M. E. Hagan ◽  
M. J. Buonsanto
Keyword(s):  
Electron Density ◽  
Ionospheric Electron Density ◽  
Density Modeling

Global Multi-layer Electron Density Modeling Based on Constraint optimization

2020 ◽  
Author(s):  
Ganesh Lalgudi Gopalakrishnan ◽  
Michael Schmidt ◽  
Eren Erdogan
Keyword(s):  
Electron Density ◽  
Space Weather ◽  
Peak Height ◽  
Optimization Approach ◽  
Iri Model ◽  
B Splines ◽  
Weather Events ◽  
The Impact ◽  
Layer Peak ◽  
Density Modeling

<p><span>Electron density is the most important key parameter to describe the </span><span>state of the ionospheric plasma </span><span>varying with latitude, longitude, altitude and time. The upper atmosphere is decomposed into the four layers D, E, F1 and F2 of the ionosphere as well as the plasmasphere. Space weather events manifest themselves with specific "signatures" in distinct ionospheric layers. Therefore, the role of each layer in characterizing the ionosphere during nominal and extreme space weather events is highly important for scientific and operational purposes. </span></p><p><span>Accordingly, we model the total electron density as the sum of the electron densities of the individual layers. The key parameters of each layer, namely peak electron density, the corresponding peak height and scale height, are modeled by series expansions in terms of polynomial B-splines for latitude and trigonometric B-splines for longitude. The Chapman profile function is chosen to define the electron density along the altitude. This way, the electron density modeling is setup as a parameter estimation problem. In the case of modelling multiple layers simultaneously, the estimation of coefficients of the key parameters becomes challenging due to the correlations between the different key parameters. </span></p><p><span>One possibility to address the above issue is by imposing constraints on the ionospheric key parameters (and by extension on the B-spline coefficients). As an example, we constrain the F2 layer peak height to be always above the F1 layer peak height. We also constrain the key parameters to be non-negative and possibly to to certain well defined bounds. This way the physical properties of the ionosphere layers are included in the modelling. We estimate the coefficients with regard to the imposition of the bounds in form of inequality constraints using a convex optimization approach. We describe the underlying mathematical procedure and validate it using </span><span>the IRI model as well as GNSS observations and electron density measurements from occultation missions. For the specific case of using IRI model data as the reference “truth”, we show the performance of the optimization algorithm using a “closed loop” validation. Such a validation allows an in-depth analysis of the impact of choosing a desired number of unknown coefficients to be estimated and the total number of constraints applied. We describe the parameterization of the different ionosphere key parameters considering the specific requirements from operational aspects (such as the need for modelling F2 layer), scientific aspects with regard to ionosphere-thermosphere studies (need for modelling the D, E or F1 layers) and also considering the aspects related to computation load. </span></p><p><span>We describe the advantages of using the optimization approach compared to the unconstrained least squares solution. While such constraints on key parameters can be fixed under nominal ionospheric conditions, but under adverse space weather effects these constraints need to be modified (constraints become stricter or more relaxed). For this purpose, we show the dynamic effect of modifying the constraints on global modelling performance and accuracy. We also provide the uncertainty of the estimated coefficients using a Monte-Carlo approach.</span></p>

Comparative study of COSMIC/FORMOSAT-3, Irkutsk incoherent scatter radar, Irkutsk Digisonde and IRI model electron density vertical profiles

2017 ◽  
Vol 60 (2) ◽  
pp. 452-460 ◽  
Author(s):  
K.G. Ratovsky ◽  
A.V. Dmitriev ◽  
A.V. Suvorova ◽  
A.A. Shcherbakov ◽  
S.S. Alsatkin ◽  
...  
Keyword(s):  
Comparative Study ◽  
Electron Density ◽  
Vertical Profiles ◽  
Incoherent Scatter Radar ◽  
Iri Model ◽  
Incoherent Scatter ◽  
Scatter Radar
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