Open Access

Table 2.

Comparison of calibration methods and criteria.

Asikainen & Mursula (2011) and Asikainen et al. (2012) Sandanger et al. (2015)
α Factors provided for channelsa P1–P3 P1–P5
Separation in space between satellites <1° magnetic latitude and longitude at foflb and <10% relative difference in L-value Only compare satellites with <1 h separation in MLT
Separation in time between comparable satellites <30 s
Data used Instantaneous measurements (2 s resolution) Mean value of one month of data from whole orbit
Number of months data from new satellite is considered non-degraded 5 12
Method for obtaining time evolution Linear, 2nd order, 3rd order, PCHIPc fit with α vs. time, or as a function of ap index Iteration method using α vs. accumulated corrected integral flux
a

P6 is excluded in all studies due to relativistic electrons contaminating the measurements.

b

foot of field line (fofl) confining each satellite.

c

Piecewise Cubic Hermite Interpolation Polynomial (PCHIP), shape preserving interpolation.

Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.

Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.

Initial download of the metrics may take a while.