There are two types of data selected from the Polar Orbiting Geophysical Observatory (POGO) for the Sq modeling process (Section 3.6); pass data and decimated data. The original pass (or orbit) data came from CD:POGODIPSRT files /ltsrt/ltogo2.001-8, ltogo4.001-8, and ltogo6.001-8. Data separated by orbit was selected for the quiet Kp days listed in Section 3.1 then was reformatted to the Sq fitting format (SQ). The residuals with respect to the QnnlF10.7 model were then compared on a pass-by-pass basis. Passes with a standard deviation greater than 15 nT were rejected from the dataset. After further analysis with the IDL Widget Data Analysis Tool, orbits numbered 169 and 196 were also deleted from the dataset and orbits 78 and 204 were added back into the dataset. Each data point was then compared to values from the AA_1 main field model. Individual points that differed more than 25 nT from these computed values were removed resulting in the file pogopc.iee.
The decimated pogo dataset originated from CD:SURVEYMISC1 files /satellite/su5002/su5002.001-003. This data was decimated to 1/3 of its size. To reduce the number of observations during dawn and dusk (primarily from OGO-4), data in these times were given a lower residual tolerance. Each data point was compared to a point computed using the 21x3030 main field model. Points that differed from the model value by more than 10 nT for dawn (local times 2 to 7) or dusk (local times 14 to 19) were eliminated from the dataset. Points at any other time with residuals greater then 30 nT were also deleted. To assure that the geographical coverage was not compromised, additional selection criteria was based on the number of points in 147 equal area bins. Only 20 points per bin were selected for dawn (local times 5 to 7) and dusk (local times 17 to 19). All points per bin were kept for all other times. Another residual limit was then applied. Any data point that deviated from the 21x3030 model by more than 12 nT was eliminated from the dataset. To compensate for the still prevalent dawn/dusk data surplus, the data was once again divided into 147 equal geographical area bins. This time only 15 points per bin were selected for dawn (local times 3 to 9) and dusk (local times 15 to 19) with other times accepting all points. As a final selection for data quality, points with a residual greater than 25 nT with respect to the AA_1 model were deleted. The final file for the decimated POGO dataset is pogodc.iee. The local time distribution and global coverage for this file is plotted in Figure 3.1.