# Towards a Real-Time Description of the Ionosphere:
## 4 Methodologies of Analysis
### Data Binning  
Both _fo_F2 and _hm_F2 exhibit variations at very different temporal and spatial scales, that are also a consequence of the varying solar and magnetic conditions. To highlight the main climatological diurnal, seasonal, spatial, solar and magnetic activity variations embedded in the data, both modeled and measured values were binned according to different schemes that are here reported in detail.  
The diurnal variation was studied in a twofold way:  
1. Data were binned as a function of the LT with fifteen minute-wide bins (96 bins in total).
2. Data were collected in three separate diurnal sectors as a function of the solar zenith angle (SZA): * Daytime: SZA \(\leq 80^{\circ}\). * Solar terminator: \(80^{\circ}<\) SZA \(<100^{\circ}\). * Nighttime: SZA \(\geq 100^{\circ}\).  
The seasonal variation has been studied in a threefold way:  
1. (only for ionosondes) Data were binned as a function of the month of the year (12 bins in total).
2. (only for COSMIC) Data were binned as a function of the day of the year (day) in bins five-day wide (73 bins in total).
3. Data were collected in four bins representative of the four seasons. Specifically, bins centered at equinoxes and solstices: * March Equinox: \(35\leq\) day \(\leq 125\). * June Solstice: \(126\leq\) day \(\leq 217\). * September Equinox: \(218\leq\) day \(\leq 309\). * December Solstice: day \(\leq 34\) OR day \(\geq 310\).  
The solar activity variation was studied by selecting the three levels of solar activity (low, mid, and high) defined in Section 3.1 on the basis of the F10.7\({}_{81}\) solar index, and by binning data as a function of F10.7\({}_{81}\) in bins two s.f.u.-wide.  
The magnetic activity variation was studied by selecting three levels of magnetic disturbance on the basis of the global \(a_{\rm p}\) index [63]:  
* Quiet magnetic activity: \(a_{\rm p}<20\) nT.
* Moderate magnetic activity: \(20\) nT \(\leq a_{\rm p}<100\) nT.
* Disturbed magnetic activity: \(a_{\rm p}\geq 100\) nT.  
\(a_{\rm p}\) values were downloaded from NASA's Space Physics Data Facility of the Goddard Space Flight Center ([[https://spdf.gsfc.nasa.gov/pub/data/omni/high_res_omni/](https://spdf.gsfc.nasa.gov/pub/data/omni/high_res_omni/)]([https://spdf.gsfc.nasa.gov/pub/data/omni/high_res_omni/](https://spdf.gsfc.nasa.gov/pub/data/omni/high_res_omni/)), accessed on 30 July 2021).  
For what concerns the spatial variation, in the case of the ionosonde dataset this is directly related to the station's geographic position. Conversely, for the COSMIC dataset, this was investigated using geographic coordinates, the magnetic QD latitude and modify. Specifically:  
1. Data were binned as a function of the geographic coordinates in bins that are 2.5\({}^{\circ}\)-wide in latitude and 5\({}^{\circ}\)-wide in longitude.
2. Data were binned as a function of the model latitude in bins that are 2.5\({}^{\circ}\)-wide.
3. Data were binned according to three ranges of model values: * Low modip: \(-30^{\circ}<\) modip \(<30^{\circ}\). * Mid modip: \(-60^{\circ}\leq\) modip \(\leq-30^{\circ}\) AND \(30^{\circ}\leq\) modip \(\leq 60^{\circ}\). * High modip: modip \(<-60^{\circ}\) AND modip \(>60^{\circ}\).