ALBERT — All Library Books, journals and Electronic Records Telegrafenberg

1

Unknown

A solar activity correction term for the IRI topside electron density model. (2021)

Bilitza, D. ; Xiong, C.

In: Advances in Space Research

add to mindlist on the mindlist

Details

Publication Date: 2021-12-08

Description: In situ measurements by the Low Earth Orbital (LEO) satellites, such as CHAMP, GRACE, and C/NOFS satellites have shown that the International Reference Ionosphere (IRI) model has shortcomings in describing the solar activity variation of the topside electron density. In particular IRI overestimates the measured densities in the topside ionosphere during the very low solar activity reached during the last solar minimum (2008–2009). We have used Alouette and ISIS topside sounder data and CHAMP, GRACE, as well as Swarm in situ measurements to deduce a correction term for the IRI electron density topside model that more accurately describes the variation with solar activity. We have used a linear variation with the solar index PF10.7 and described the latitudinal and altitudinal variation of the regression parameters A0 and A1 (intercept and slope). We find good agreement between the regression parameters deduced from the topside sounder and from the CHAMP and GRACE observations. Swarm results show the same latitudinal structure as the other data sets, however, a scaling factor is needed to obtain agreement of the absolute values. The new model was evaluated with Alouette and ISIS topside sounder, as well as LEO satellites in situ data showing a significant improvement over the current IRI model.

Language: English

Type: info:eu-repo/semantics/article

Format: application/pdf

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

PAPER (OA)

S·F·X

PDF

Overview

2

Unknown

The ISIS Topside Sounder Project - Rescuing a Unique Ionospheric Data Set (2023)

Bilitza, D. ; Benson, R.

In: XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)

add to mindlist on the mindlist

Details

Publication Date: 2023-07-04

Description: Modeling of the topside ionosphere (from F peak to ~2000 km) suffers from a scarcity of data because ground ionosondes only reach up to the F peak. Millions of topside ionograms had been recorded by the Alouette 1,2 and ISIS 1,2 satellites between 1962 and 1990 that were never fully analyzed. The satellites carried topside sounders, the satellite equivalent of the ground-based ionosonde, and provided the first global view of the topside ionosphere. The topside sounders were designed as analog systems that recorded ionograms on 35 mm film for analysis by visual inspection. Many nations participated in the data analysis process that involved manual scaling of the ionograms and inversion into electron density profiles. But because of the tedious manual process only a small percentage of the recorded ionograms was converted to electron density profiles. We were able to digitize a significant portion of the 60 satellite years of analog data before the tapes were discarded. In a second step we worked with a team at the University of Massachusetts Lowell who developed the Topside Ionogram Scalar with True-Height inversion (TOPIST) software for the automated scaling and inversion of the traces on the digital ionograms into electron density profiles thus avoiding the very limiting manual process. As a result of our project close to a million digital topside ionograms and electron density profiles are now available for browsing/plotting/downloading at NASA's Space Physics Data Facility (https://spdf.gsfc.nasa.gov). We will review some of the science results based on the digital data.

Language: English

Type: info:eu-repo/semantics/conferenceObject

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

PAPER (OA)

S·F·X

Overview

3

Unknown

The International Reference Ionosphere (IRI): A Standard Description of Earth’s Ionosphere (2023)

Bilitza, D. ; Truhlik, V. ; Krankowski, A. ; [et al.]

In: XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)

add to mindlist on the mindlist

Details

Publication Date: 2023-07-04

Description: The International Reference Ionosphere (IRI) model is recognized as the official standard for Earth's ionosphere by the International Standardization Organization, the International Union of Radio Science, the Committee on Space Research, and the European Cooperation for Space Standardization. As requested by these organizations, IRI is an empirical model representing the primary ionospheric parameters based on the long data record that exists from ground and space observations of the ionosphere. The core model describes monthly averages of the electron density, electron temperature, ion temperature, and ion composition globally in the altitude range from 60 to 2,000 km. Over time additional parameters were added in response to community requests, this includes the equatorial ion drift, the occurrence probability of spread-F, auroral boundaries and the electron content from the bottom of the ionosphere to a user-specified altitude. We will present the latest version of the model, which includes several improvements and new models for the ion temperature, the ion drift, the D-region electron density, and the electron density in the topside and plasmasphere. A special focus in recent years has been on assimilative methods to bring IRI predictions closer to real-time conditions with the help of measured parameters. An overview of these methods will be provided and we will discuss the future plans for the IRI model. A comprehensive description of the model was recently published in Reviews of Geophysics (Bilitza et al., doi:10.1029/2022RG000792) providing a deeper understanding of the model architecture, its scientific background and its mathematical formalism.

Language: English

Type: info:eu-repo/semantics/conferenceObject

Permalink