Equatorial-PRIMO: Ionospheric Models and Observations

1. Welcome to Equatorial-PRIMO (Problems Related to Ionospheric Models and Observations) • Original PRIMO dealt with mid-latitude comparisons • Most theoretical models underestimated the noon-time, Nmax values by a factor of 2 at solar maximum • It’s appropriate to start a multi-year, Equatorial-PRIMO with similar goals as the original PRIMO workshops

2. Transport Processes in the Equatorial Ionosphere

3. Equatorial-PRIMO (Problems Related to Ionospheric Models and Observations) • We do not fully understand all the relevant physics of the equatorial ionosphere, so that current models do not completely agree with each other and are not able to accurately reproduce observations. • To understand the strengths and the limitations of theoretical, time-dependent, low-latitude ionospheric models in representing observed ionospheric structure and variability under low to moderate solar activity and geomagnetic quiet conditions, in order to better understand the underlying ionospheric physics and develop improved models. • The vertical drift and global electric field at equatorial region are calculated through the electrodynamics process which is strongly controlled by the neutral wind velocity, ionospheric conductivity, and geomagnetic field. Comparing the similarities and dissimilarities of inputs and outputs among different models as well as the observations helps us to evaluate the reliability of existing physics.

4. A set of theoretical ionospheric models require neutral atmospheric densities and temperatures, neutral winds, ExB drift velocities as inputs and calculate and Ion and electron densities as a function of altitude, latitude and local time. Their calculations are not self-consistently. • The Utah State University (USU) ”Ionospheric Forecast Model (IFM)” • The Space Environment Corporation (SEC) “Low Latitude Ionospheric Specification Model (LLIONS)” • The AFRL “Physics Based Model (PBMOD)” • The “Global Ionosphere and Plasmasphere (GIP)” model. • The NRL “Still Another Model of the Ionosphere 2 (SAMI2)” • The other set of ionosphere-thermosphere models are time dependent, three dimensional, non-linear models which solve the fully coupled, thermodynamic, and continuity equations of the neutral gas self-consistently with the ion energy, ion momentum, and ion continuity equations. • The NRL “Still Another Model of the Ionosphere 3 (SAMI3)” • The Coupled Thermosphere Ionosphere Plasmasphere Electrodynamics (CTIPe) model • The NCAR “Thermosphere-Ionosphere-Electrodynamics general circulation model (TIE-GCM)” and “Thermosphere-Ionosphere-Mesosphere-Electrodynamics general circulation model (TIME-GCM)” • University of Michigan “Global Ionosphere-Thermosphere Model (GITM)” • Integrated Dynamics through Earth’s Atmosphere (IDEA).

5. Equatorial-PRIMO (Problems Related to Ionospheric Models and Observations) 13:30 – 13:35 Introduction of Equatorial-PRIMO Workshop 13:35 – 13:40 Jan Sojka – IFM 13:40 – 13:45 Vince Eccles – LLIONS 13:45 – 13:50 John Retterer – PBMOD 13:50 – 13:55 Tzu-Wei Fang – GIP 13:55 – 14:05 Joe Huba – SAMI2 and SAMI3 14:05 – 14:10 Art Richmond – TIE-GCM 14:10 – 14:15 Geoff Crowley – TIME-GCM 14:15 – 14:20 Aaron Ridley – GITM 14:20 – 14:30 Tim Fuller-Rowell – CTIPe and IDEA 14:30 – 15:30 Round-table Discussion

6. Burnside Factor (the collision frequency between O+-O) in the topside was multiplied by 1.7. But today, the evidence suggests the factor is closer to 1.0. Self consistent model – TIGCM and GTIM [Anderson et al. JGR, 1998]

7. model vertical drifts 50 30 10 -10 -30 4 8 12 16 20 0 -50 LT (hr) For self-consistent models, the diurnal variation of vertical drift at magnetic equator in Jicamarca longitude and the longitudinal variation of equatorial vertical drift at 0UT. Height variation of drift at daytime and nighttime. [Scherliess and Fejer, 1999]

8. The zonal and meridional wind velocity (Lon vs. ±60° Lat at 0UT) at 120 km (or E region) and 300 km (or F region) used as specified input or generated by the model.

9. For self-consistent models, the daytime and nighttime Pederson and Hall conductivities (±30° Lat vs. height) in Jicamarca longitude. http://wdc.kugi.kyoto-u.ac.jp/ionocond/sigcal/index.html

10. The daytime and nighttime electron density distribution (±30° Lat vs. height) at Jicamarca longitude.

11. Equatorial-PRIMO (Problems Related to Ionospheric Models and Observations) (a) Chemical reaction rates, photoionization processes, diffusion coefficients, nighttime ionization? (b) Boundary conditions, numerical techniques, spatial resolution? (1) The zonal and meridional wind velocity (Lon vs. ±60° Lat at 0UT) at 120 km (or E region) and 300 km (or F region) used as specified input or generated by the model. (2) The daytime and nighttime electron density distribution (±30° Lat vs. height) in Jicamarca longitude. (3) For self-consistent models, the daytime and nighttime Pederson and Hall conductivities (±30° Lat vs. height) in Jicamarca longitude. (4) For self-consistent models, the diurnal variation of vertical drift at magnetic equator in Jicamarca longitude and the longitudinal variation of equatorial vertical drift at 0UT. (5) For self-consistent models, the height variation of vertical drifts at magnetic equator in Jicamarca longitude during the daytime and nighttime.