TEC over continental US and Europe for the fall equinox and low solar flux conditions

The files contain median TEC (total electron content) values for a given geographic sector for a fall equinox and low solar flux conditions.<br> The 10th, 25th, 75th, and 90th percentiles are also included. These median TEC values were calculated using TEC data provided by the CEDAR Madrigal database for the years 2000-2018.<br> Median values of TEC and different percentiles were calculated for the following<br> conditions: low solar activity (F10.7 daily index is 70 ± 5 SFU; 81‐day average F10.7 index is 70 ± 5 SFU),<br> low geomagnetic activity (daily Ap index &lt; 15 for the current day and previous 24 h), average or below average<br> stratospheric planetary wave activity at 10 hPa and 60°S, and centered on 15 September with a ±15‐day window.<br> Average level of stratospheric planetary wave activity was calculated from 40+ years of MERRA data. The Madrigal<br> database contains 79 days that satisfy the aforementioned conditions, with data collected in 2008, 2009,<br> and 2018. The TEC observations for the selected 79 days were then binned in 30‐min intervals, resulting<br> in several hundred data points per each 1° longitude x ~ 1° latitude bin in areas with good data coverage.<br> Median TEC values determined from these bins were used as a baseline<br> that describes the “dynamically quiet” ionosphere in each geographic sector with high resolution in latitude<br> and longitude. Different percentiles were used to describe typical quiet-time variability. The users are advised to use median TEC only in areas with sufficient number of data points (&gt; 50) included in the median.