NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Measurements and IRI Model Predictions During the Recent Solar MinimumCycle 23 was exceptional in that it lasted almost two years longer than its predecessors and in that it ended in an extended minimum period that proved all predictions wrong. Comparisons of the International Reference Ionosphere (IRI) with CHAMP and GRACE in-situ measurements of electron density during the minimum have revealed significant discrepancies at 400-500 km altitude. Our study investigates the causes for these discrepancies with the help of ionosonde and Planar Langmuir Probe (PLP) data from the Communications/Navigation Outage Forecasting System (C/NOFS) satellite. Our C/NOFS comparisons confirm the earlier CHAMP and GRACE results. But the ionosonde measurements of the F-peak plasma frequency (foF2) show generally good agreement throughout the whole solar cycle. At mid-latitude stations yearly averages of the data-model difference are within 10% and at low latitudes stations within 20%. The 60-70% differences found at 400-500 km altitude are not seen at the F peak. We will discuss how these seemingly contradicting results from the ionosonde and in situ data-model comparisons can be explained and which parameters need to be corrected in the IRI model.
Document ID
20120015550
Document Type
Reprint (Version printed in journal)
Authors
Bilitza, Dieter (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Brown, Steven A. (George Mason Univ. Fairfax, VA, United States)
Wang, Mathew Y. (George Mason Univ. Fairfax, VA, United States)
Souza, Jonas R. (Instituto Nacional de Pesquisas Espacias Sao Jose dos Campos, Brazil)
Roddy, Patrick A. (Air Force Research Lab. Hanscom AFB, MA, United States)
Date Acquired
August 26, 2013
Publication Date
July 17, 2012
Publication Information
Publication: Journal of Atmospheric Solar-Terrestrial Physics
Volume: 86
Subject Category
Geophysics
Report/Patent Number
GSFC.JA.7162.2012
Funding Number(s)
CONTRACT_GRANT: NNX09AJ74G
CONTRACT_GRANT: NSF ATM-0819440
Distribution Limits
Public
Copyright
Other