**Data real time:**

- Magnetometer data
- Riometer data
- Ionogramms
- Atmospheric electric field

**Arctic stations**

**Antarctic stations**

**Middle latitude station**

** **

**Parameters:**

**Parameters α, β and φ are used to calculate PC index basing on
data of magnetic measurements at stations Thule and Vostok. Angle φ
determines the optimal orientation of the magnetic disturbance vector δF
related to the geoeffective interplanetary electric field E_{KL }in different UT times. Coefficients
α and β are the linear
regression parameters, slope and intersection, connecting values δF and
PC. The parameters α, β and φ were derived independently by
data for solar maximum epoch (1998-2001) and by data for solar minimum epoch
(1997, 2007-2009). It was demonstrated that usage of a proper quiet daily
variation (QDC), as a level of reference for values of the polar cap magnetic
disturbance, leads to invariance of the parameters
a,
β and
f
irrespective of the solar
activity epoch. Afterwards, the parameters α, β and φ were
calculated by data for full cycle of solar activity (1995-2005) to derive the
statistically justified quantities for any minute of any day of year. Thus,
parameters a,
β and
f
presented in Table with 1-min
resolution are regarded as valid for ever provided the appropriate quite daily
variation (QDC) are used. The parameters are given for leap and usual
years.**

Contact :

Troshichev O.A.

olegtro@aari.nw.ru