Abstract
During a 10-day URSI World Day observational campaign beginning on August 1, 2011, an isolated, major geomagnetic storm occurred. On August 5, Kp reached values of 8- and Dst dropped to -113nT. The occurrence of this isolated storm in the middle of a 10-day URSI World Day campaign provides and unprecedented opportunity to observe the coupling of solar wind energy into the magnetosphere and to evaluate the varied effects that occur in the coupled magnetosphere-ionosphere-thermosphere system. Dramatic changes in the ionosphere are seen at every one of the active radar stations, extending from Greenland down to equatorial Peru in the American sector and at middle latitudes in Ukraine. Data from TIMED and THEMIS are shown to support initial interpretations of the observations, where we focus on processes in the middle latitude afternoon sector during main phase, and the formation of a dense equatorial ionosphere during storm recovery. The combined measurements strongly suggest that the changes in ionospheric conditions observed after the main storm phase can be attributed in large part to changes in the stormtime thermosphere. This is through the generation of disturbance dynamo winds and also global neutral composition changes that either reduce or enhance plasma densities in a manner that depends mainly upon latitude. Unlike larger storms with possibly more sustained forcing, this storm exhibits minimal effects of persistent meridional stormtime wind drag, and little penetration of solar wind electric potentials to low latitudes. It is, therefore, an outstanding example of an impulsive event that exhibits longer-term effects through modification of the background atmosphere.
| Original language | English |
|---|---|
| Pages (from-to) | 47-55 |
| Number of pages | 9 |
| Journal | Journal of Atmospheric and Solar-Terrestrial Physics |
| Volume | 134 |
| DOIs | |
| Publication status | Published - Nov 1 2015 |
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All Science Journal Classification (ASJC) codes
- Geophysics
- Atmospheric Science
- Space and Planetary Science
Cite this
The August 2011 URSI World Day campaign : Initial results. / Immel, Thomas J.; Liu, Guiping; England, Scott L.; Goncharenko, Larisa P.; Erickson, Philip J.; Lyashenko, Mykhaylo V.; Milla, Marco; Chau, Jorge; Frey, Harald U.; Mende, Stephen B.; Zhou, Qihou; Stromme, Anja; Paxton, Larry J.
In: Journal of Atmospheric and Solar-Terrestrial Physics, Vol. 134, 01.11.2015, p. 47-55.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - The August 2011 URSI World Day campaign
T2 - Initial results
AU - Immel, Thomas J.
AU - Liu, Guiping
AU - England, Scott L.
AU - Goncharenko, Larisa P.
AU - Erickson, Philip J.
AU - Lyashenko, Mykhaylo V.
AU - Milla, Marco
AU - Chau, Jorge
AU - Frey, Harald U.
AU - Mende, Stephen B.
AU - Zhou, Qihou
AU - Stromme, Anja
AU - Paxton, Larry J.
PY - 2015/11/1
Y1 - 2015/11/1
N2 - During a 10-day URSI World Day observational campaign beginning on August 1, 2011, an isolated, major geomagnetic storm occurred. On August 5, Kp reached values of 8- and Dst dropped to -113nT. The occurrence of this isolated storm in the middle of a 10-day URSI World Day campaign provides and unprecedented opportunity to observe the coupling of solar wind energy into the magnetosphere and to evaluate the varied effects that occur in the coupled magnetosphere-ionosphere-thermosphere system. Dramatic changes in the ionosphere are seen at every one of the active radar stations, extending from Greenland down to equatorial Peru in the American sector and at middle latitudes in Ukraine. Data from TIMED and THEMIS are shown to support initial interpretations of the observations, where we focus on processes in the middle latitude afternoon sector during main phase, and the formation of a dense equatorial ionosphere during storm recovery. The combined measurements strongly suggest that the changes in ionospheric conditions observed after the main storm phase can be attributed in large part to changes in the stormtime thermosphere. This is through the generation of disturbance dynamo winds and also global neutral composition changes that either reduce or enhance plasma densities in a manner that depends mainly upon latitude. Unlike larger storms with possibly more sustained forcing, this storm exhibits minimal effects of persistent meridional stormtime wind drag, and little penetration of solar wind electric potentials to low latitudes. It is, therefore, an outstanding example of an impulsive event that exhibits longer-term effects through modification of the background atmosphere.
AB - During a 10-day URSI World Day observational campaign beginning on August 1, 2011, an isolated, major geomagnetic storm occurred. On August 5, Kp reached values of 8- and Dst dropped to -113nT. The occurrence of this isolated storm in the middle of a 10-day URSI World Day campaign provides and unprecedented opportunity to observe the coupling of solar wind energy into the magnetosphere and to evaluate the varied effects that occur in the coupled magnetosphere-ionosphere-thermosphere system. Dramatic changes in the ionosphere are seen at every one of the active radar stations, extending from Greenland down to equatorial Peru in the American sector and at middle latitudes in Ukraine. Data from TIMED and THEMIS are shown to support initial interpretations of the observations, where we focus on processes in the middle latitude afternoon sector during main phase, and the formation of a dense equatorial ionosphere during storm recovery. The combined measurements strongly suggest that the changes in ionospheric conditions observed after the main storm phase can be attributed in large part to changes in the stormtime thermosphere. This is through the generation of disturbance dynamo winds and also global neutral composition changes that either reduce or enhance plasma densities in a manner that depends mainly upon latitude. Unlike larger storms with possibly more sustained forcing, this storm exhibits minimal effects of persistent meridional stormtime wind drag, and little penetration of solar wind electric potentials to low latitudes. It is, therefore, an outstanding example of an impulsive event that exhibits longer-term effects through modification of the background atmosphere.
UR - http://www.scopus.com/inward/record.url?scp=84943578335&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84943578335&partnerID=8YFLogxK
U2 - 10.1016/j.jastp.2015.09.005
DO - 10.1016/j.jastp.2015.09.005
M3 - Article
AN - SCOPUS:84943578335
VL - 134
SP - 47
EP - 55
JO - Journal of Atmospheric and Solar-Terrestrial Physics
JF - Journal of Atmospheric and Solar-Terrestrial Physics
SN - 1364-6826
ER -