University of Oulu

Virtanen, I. I., Tesfaw, H. W., Roininen, L., Lasanen, S., & Aikio, A. (2021). Bayesian filtering in incoherent scatter plasma parameter fits. Journal of Geophysical Research: Space Physics, 126, e2020JA028700. https://doi.org/10.1029/2020JA028700

Bayesian filtering in incoherent scatter plasma parameter fits

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Author: Virtanen, Ilkka I.1; Tesfaw, Habtamu W.1; Roininen, Lassi2;
Organizations: 1Space Physics and Astronomy Research Unit, University of Oulu, Oulu, Finland
2School of Engineering Science, Lappeenranta-Lahti University of Technology, Lappeenranta, Finland
3Sodankylä Geophysical Observatory, University of Oulu, Sodankylä, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 2 MB)
Persistent link: http://urn.fi/urn:nbn:fi-fe202103298625
Language: English
Published: American Geophysical Union, 2021
Publish Date: 2021-03-29
Description:

Abstract

Incoherent scatter (IS) radars are invaluable instruments for ionospheric physics, since they observe altitude profiles of electron density (Ne), electron temperature (Te), ion temperature (Ti) and line‐of‐sight plasma velocity (Vi) from ground. However, the temperatures can be fitted to the observed IS spectra only when the ion composition is known, and resolutions of the fitted plasma parameters are often insufficient for auroral electron precipitation, which requires high resolutions in both range and time. The problem of unknown ion composition has been addressed by means of the full‐profile analysis, which assumes that the plasma parameter profiles are smooth in altitude, or follow some predefined shape. In a similar manner, one could assume smooth time variations, but this option has not been used in IS analysis. We propose a plasma parameter fit technique based on Bayesian filtering, which we have implemented as an additional Bayesian Filtering Module (BAFIM) in the Grand Unified Incoherent Scatter Design and Analysis Package (GUISDAP). BAFIM allows us to control gradients in both time and range directions for each plasma parameter separately. With BAFIM we can fit F1 region ion composition together with Ne, Te, Ti and Vi, and we have reached 4 s/900 m time/range steps in four‐parameter fits of Ne, Te, Ti and Vi in E region observations of auroral electron precipitation.

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Series: Journal of geophysical research. Space physics
ISSN: 2169-9380
ISSN-E: 2169-9402
ISSN-L: 2169-9380
Volume: 126
Issue: 3
Article number: e2020JA028700
DOI: 10.1029/2020JA028700
OADOI: https://oadoi.org/10.1029/2020JA028700
Type of Publication: A1 Journal article – refereed
Field of Science: 115 Astronomy and space science
Subjects:
Funding: This work is supported by the Academy of Finland, application numbers 285474, 326240, and 301542, and the Kvantum institute of the University of Oulu. EISCAT is an international association supported by research organizations in China (CRIRP), Finland (SA), Japan (NIPR and STEL), Norway (NFR), Sweden (VR), and the United Kingdom (NERC).
Academy of Finland Grant Number: 285474
326240
301542
Detailed Information: 285474 (Academy of Finland Funding decision)
326240 (Academy of Finland Funding decision)
301542 (Academy of Finland Funding decision)
Copyright information: © 2021. The Authors. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
  https://creativecommons.org/licenses/by/4.0/