1. Variation of Total Electron Contents (TECs) during the last solar minimum in Rome
A. Ippolito(1), C. Cesaroni(1) and L. Spogli(1,2)
1. Istituto Nazionale di geofisica e Vulcanologia, Via di Vigna Murata 605, Rome, ITALY
2. SpacEarth Technology, Via di Vigna Murata 605, Rome, ITALY

2. The last solar minimum ( ) has been considered to identify anomalous behaviours of Total Electron Content (TECs) variations
To the scope, calibrated vertical TEC (vTEC) data, recorded every 15 minutes from the GNSS receiver of the Rome station, have been studied.
background value
monthly median vTEC calibrated data
vTEC Anomaly
vTEC variation > ± 2σ over the background level

3. Quiet and disturbed periods defined by geomagnetic indices ap and AE
ap (nT)
Level
Geomagnetic Activity
0- 32 G0
Quiet
39-56 G1
Minor Storm
67-94 G2
Moderate Storm G3
Strong Storm G4
Severe Storm
400 G5
Extreme Storm
Quiet and disturbed periods defined by geomagnetic indices ap and AE
ap index value of the at the time when the anomaly is detected and for the previous 24 hours.
AE value up to 6 hours before the occurrence of the anomaly. G5 G4 G3 G2 G1
G0 AE>100nT
QUIET
(G0
AE<100nT)
2007
Neg 4 1
Pos 14 41 7
2008 2 3 6 10 44
2009 49 17

4. No data, for the deep solar minimum, in the levels G3 – G4 and G5.
Characterization of the observed vTEC anomalies with respect to the related geomagnetic conditions
Higher number of positive ionospheric anomalies respect to negative ones
The number of positive vTEC anomalies, as well as the percentage, is greater in 2009
No data, for the deep solar minimum, in the levels G3 – G4 and G5.
Acknowledgments:
This work has been supported by LIMADOU-Science project and SAFE project.