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Patterns of F2-layer variability

Patterns of F2-layer variability
Patterns of F2-layer variability
The ionosphere displays variations on a wide range of time-scales, ranging from operational time-scales of hours and days up to solar cycles and longer. We use ionosonde data from thirteen stations to study the day-to-day variability of the peak F2-layer electron density, NmF2, which we use to define quantitative descriptions of variability versus local time, season and solar cycle. On average, for years of medium solar activity (solar decimetric flux approximately 140 units), the daily fluctuations of NmF2 have a standard deviation of 20% by day and 33% by night. We examine and discuss the patterns of behaviour of ionospheric and geomagnetic variability, in particular the equinoctial peaks. For further analysis we concentrate on one typical midlatitude station, Slough. We find that the standard deviations of day-to-day and night-to-night values of Slough NmF2 at first increase with increasing length of the dataset, become fairly constant at lengths of 10–20 days and then increase further (especially at equinox) because of seasonal changes. We found some evidence of two-day waves, but they do not appear to be a major feature of Slough's F2 layer. Putting together the geomagnetic and ionospheric data, and taking account of the day-to-day variability of solar and geomagnetic parameters, we find that a large part of F2-layer variability is linked to that of geomagnetic activity, and attribute the rest to ‘meteorological’ sources at lower levels in the atmosphere. We suggest that the greater variability at night is due to enhanced auroral energy input, and to the lack of the strong photochemical control of the F2-layer that exists by day.
Space weather, Ionosphere, F-region, Ionosphere variability
1661-1680
Rishbeth, H.
fb69f152-f92f-4579-95b2-532898a077d1
Mendillo, M.
0b4e45c2-16ab-4130-aace-eaf6e3f6b561
Rishbeth, H.
fb69f152-f92f-4579-95b2-532898a077d1
Mendillo, M.
0b4e45c2-16ab-4130-aace-eaf6e3f6b561

Rishbeth, H. and Mendillo, M. (2001) Patterns of F2-layer variability. Journal of Atmospheric Solar-Terrestrial Physics, 63 (15), 1661-1680. (doi:10.1016/S1364-6826(01)00036-0).

Record type: Article

Abstract

The ionosphere displays variations on a wide range of time-scales, ranging from operational time-scales of hours and days up to solar cycles and longer. We use ionosonde data from thirteen stations to study the day-to-day variability of the peak F2-layer electron density, NmF2, which we use to define quantitative descriptions of variability versus local time, season and solar cycle. On average, for years of medium solar activity (solar decimetric flux approximately 140 units), the daily fluctuations of NmF2 have a standard deviation of 20% by day and 33% by night. We examine and discuss the patterns of behaviour of ionospheric and geomagnetic variability, in particular the equinoctial peaks. For further analysis we concentrate on one typical midlatitude station, Slough. We find that the standard deviations of day-to-day and night-to-night values of Slough NmF2 at first increase with increasing length of the dataset, become fairly constant at lengths of 10–20 days and then increase further (especially at equinox) because of seasonal changes. We found some evidence of two-day waves, but they do not appear to be a major feature of Slough's F2 layer. Putting together the geomagnetic and ionospheric data, and taking account of the day-to-day variability of solar and geomagnetic parameters, we find that a large part of F2-layer variability is linked to that of geomagnetic activity, and attribute the rest to ‘meteorological’ sources at lower levels in the atmosphere. We suggest that the greater variability at night is due to enhanced auroral energy input, and to the lack of the strong photochemical control of the F2-layer that exists by day.

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More information

Published date: 2001
Keywords: Space weather, Ionosphere, F-region, Ionosphere variability

Identifiers

Local EPrints ID: 9167
URI: http://eprints.soton.ac.uk/id/eprint/9167
PURE UUID: 322acfae-40d6-4234-a414-bed58aa4ab96

Catalogue record

Date deposited: 27 Sep 2004
Last modified: 15 Mar 2024 04:55

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Contributors

Author: H. Rishbeth
Author: M. Mendillo

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