Ionospheric Space Weather
Longitude Dependence and Lower Atmosphere Forcing
Geophysical Monograph Series

This monograph is the outcome of an American Geophysical Union Chapman Conference on longitude and hemispheric dependence of ionospheric space weather, including the impact of waves propagating from the lower atmosphere. The Chapman Conference was held in Africa as a means of focusing attention on an extensive geographic region where observations are critically needed to address some of the fundamental questions of the physical processes driving the ionosphere locally and globally.  The compilation of papers from the conference describes the physics of this system and the mechanisms that control ionospheric space weather in a combination of tutorial-like and focused articles that will be of value to the upper atmosphere scientific community in general and to ongoing global magnetosphere-ionosphere-thermosphere (MIT) modeling efforts in particular. A number of articles from each science theme describe details of the physics behind each phenomenon that help to solve the complexity of the MIT system. Because this volume is an outcome of the research presented at this first space science Chapman Conference held in Africa, it has further provided an opportunity for African scientists to communicate their research results with the international community. In addition, the meeting and this conference volume will greatly enhance the space science education and research interest in the African continent and around the world.

Ionospheric Space Weather includes articles from six science themes that were discussed at the Chapman Conference in 2012. These include:

• Hemispherical dependence of magnetospheric energy injection and the thermosphere-ionosphere response
• Longitude and hemispheric dependence of storm-enhanced densities (SED)
• Response of the thermosphere and ionosphere to variability in solar radiation
• Longitude spatial structure in total electron content and electrodynamics
• Temporal response to lower-atmosphere disturbances
• Ionospheric irregularities and scintillation

Ionospheric Space Weather: Longitude Dependence and Lower Atmosphere Forcing will be useful to both active researchers and advanced graduate students in the field of physics, geophysics, and engineering, especially those who are keen to acquire a global understanding of ionospheric phenomena, including observational information from all longitude sectors across the globe.

Contributors vii

Preface xi

Part I Hemispherical Dependence of Magnetospheric Energy Injection and the Thermosphere-Ionosphere Response 1

1 Interhemispheric Asymmetries in Magnetospheric Energy Input 3
Eftyhia Zesta, Athanasios Boudouridis, James M Weygand, Endawoke Yizengaw, Mark B Moldwin, and Peter Chi

2 Simultaneity and Asymmetry in the Occurrence of Counterequatorial Electrojet along African Longitudes 21
A Babatunde Rabiu, Olanike O Folarin, Teiji Uozumi, and Akimasa Yoshikawa

3 Stormtime Equatorial Electrojet Ground-Induced Currents: Increasing Power Grid Space Weather Impacts at Equatorial Latitudes 33
Mark B Moldwin and Justin S Tsu

4 Differences in Midlatitude Ionospheric Response to Magnetic Disturbances at Northern and Southern Hemispheres and Anomalous Response During the Last Extreme Solar Minimum 41
Dalia Burešová and Jan Laštovička

Part II Longitude Dependence of Storm-Enhanced Densities (SEDs) 59

5 Longitude and Hemispheric Dependencies in Storm-Enhanced Density 61
Roderick A Heelis

6 Solar Cycle 24 Observations of Storm-Enhanced Density and the Tongue of Ionization 71
Anthea J Coster, Philip J Erickson, John C Foster, Evan G Thomas, J Michael Ruohoniemi, and Joseph Baker

7 A Global Ionospheric Range Error Correction Model for Single-Frequency GNSS Users 85
Norbert Jakowski and Mohammed Mainul Hoque

Part III Longitude Spatial Structure in Total Electron Content and Electrodynamics 93

8 Determining the Longitude Dependence of Vertical E × B Drift Velocities Associated with the Four-Cell, Nonmigrating Tidal Structure 95
David Anderson and Tzu-Wei Fang

9 Imaging the Global Vertical Density Structure from the Ground and Space 105
Endawoke Yizengaw and Brett A Carter

10 On the Longitudinal Dependence of the Equatorial Electrojet 115
Vafi Doumbia and Oswald Didier Franck Grodji

11 Tomographic Reconstruction of Ionospheric Electron Density Using Altitude-Dependent Regularization Strength over the Eastern Africa Longitude Sector 127
Gizaw Mengistu Tsidu, Gebreab Kidanu, and Gebregiorgis Abraha

12 Variation of the Total Electron Content with Solar Activity During the Ascending Phase of Solar Cycle 24 Observed at Makerere University, Kampala 145
Florence M D’ujanga, Phillip Opio, and Francis Twinomugisha

13 Longitudinal Dependence of Day-to-Day Variability of Critical Frequency of Equatorial Type Sporadic E (foEsq) 155
Emmanuel O Somoye, Andrew O Akala, Aghogho Ogwala, Eugene O Onori, Rasaq A Adeniji-Adele, and Enerst E Iheonu

Part IV Temporal Response to Lower Atmosphere Disturbances 163

14 Impact of Migrating Tides on Electrodynamics During the January 2009 Sudden Stratospheric Warming 165
Timothy J Fuller-Rowell, Tzu-Wei Fang, Houjun Wang, Vivien Matthias, Peter Hoffmann, Klemens Hocke, and Simone Studer

15 Simultaneous Measurements and Monthly Climatologies of Thermospheric Winds and Temperatures in the Peruvian and Brazilian Longitudinal Sectors 175
John W Meriwether, Jonathan J Makela, and Daniel J Fisher

16 Observations of TIDs over South and Central America 187
Cesar E Valladares, Robert Sheehan, and Edgardo E Pacheco

17 Modeling the East African Ionosphere 207
Melessew Nigussie, Baylie Damtie, Endawoke Yizengaw, and Sandro M Radicella

Part V Response of the Thermosphere and Ionosphere to Variability in Solar Radiation 225

18 Ionospheric Response to X-Ray and EUV Flux Changes During Solar Flares: A Review 227
 Ludger Scherliess

19 Spectrally Resolved X-Ray and Extreme Ultraviolet Irradiance Variations During Solar Flares 243
Thomas N Woods, Francis G Eparvier, and James P Mason

Part VI Ionospheric Irregularities and Scintillation 255

20 Effect of Magnetic Declination on Equatorial Spread F Bubble Development 257
Joseph D Huba

21 Global Ionospheric Electron Density Disturbances During the Initial Phase of a Geomagnetic Storm on 5 April 2010 263
Chigomezyo M Ngwira and Anthea J Coster

Index 281

Dr. Tim Fuller-Rowell is a Senior Research Scientist and a Fellow of the Cooperative  Institute for Research in Environmental Sciences at the University of Colorado Boulder. Tim has contributed book chapters in the AGU GM series and journal articles in AGU journal JGR and Geophysical Research Letters. He has co-edited an AGU volume in the GM series.

Dr. Endawoke Yizengaw is a Senior Research Scientist in the Institute for Scientific Research, at the Boston College. Endawoke has published journal articles in AGU journal JGR and Geophysical Research Letters.

Ms. Patricia H. Doherty is the Director and Senior Scientist in the Institute for Scientific Research at the Boston College.

Dr. Sunanda Basu is a Senior Research Physicist in the Institute for Scientific Research at the Boston College. She has been the Former Program Director of Aeronomy, NSF Division of Atmospheric & Geospace Sciences (1992-2002). She has also been the Chair, SCOSTEP Program on Climate and Weather of the Sun-Earth System (2002-2006) and former Chair of the AGU Development Board (2010-2012). Sunanda has published several journal articles in AGU journal JGR and Geophysical Research Letters.