Space Weather Activities at CLS Ph. Yaya J.-J. Valette CLS (Collecte Localisation Satellites) Toulouse, FRANCE

Page 2 Summary -Ionospheric scintillations -Solar and geomagnetic indices -Solar Energetic Particle Events ESWW6, Bruges, 16 nov. 2009

Page 3 Summary -Ionospheric scintillations -Solar and geomagnetic indices -Solar Energetic Particle Events ESWW6, Bruges, 16 nov. 2009

Page 4 Ionospheric Scintillations ESWW6, Bruges, 16 nov Equatorial & auroral regions : GNSS signals may be affected by night ionospheric scintillations : - signal amplitude and phase strongly fluctuate during several hours - part of the satellite constellation may be unavailable  possible service break for real time applications especially for high positioning precision applications. USER NEEDS : - permanent observation network - precise positioning for offshore industry  2003 : Nowcast monitoring of ionospheric scintillations (ESA SW pilot experiment) : -Hourly processing of IGS network  empirical ROTI index (based on phase fluctuation) -Collaborations : ENSTB, AIUB, LPCE, Fugro : ISM equatorial network (ESA ARTES-5)  S4 &    indices -Collaboration : IEEA, ENTSB, DLR, GMV, with CNES support 2009 : proposition of an extension of the previous work (ESA ITT 6194) - ISM network extension to auroral sites - signal extension to Galileo  Applications for offshore industry : avoid economic loss during marine observation campaigns  need for short term prediction (only climatological forecast models are available now). How ? Prediction of the coming night activity from the first hours after sunset.

Page 5 Ionospheric Scintillations ESWW6, Bruges, 16 nov Phase fluctuation : (L2-L1) Amplitude fluctuation : S1 (signal strength) Yellowknife 29 oct storm (IGS rinex 1 s) Amplitude fluctuation : S2 (signal strength) More than half links affected during ~20 minutes Night of 5-6 Dec 2006, seen from Cayenne ISM: a worst case of scintillations occurrence (6 mn histograms)

Ionospheric Scintillations ESWW6, Bruges, 16 nov Comparison at colocated sites 5 th Apr Bandung/Cibinong (100 km) 1 st Dec Cayenne/Kourou (50 km) ISMIGS ISMIGS Cayenne Kourou scint. index (S4 or ROTI)

Page 7 Summary -Ionospheric scintillations -Solar and geomagnetic indices -Solar Energetic Particle Events ESWW6, Bruges, 16 nov. 2009

Page 8 Solar and geomagnetic indices When flying up to an altitude of 1000 km, a satellite is submitted to a drag force due to neutral particles of the thermosphere. Their density and concentration at a given altitude are sensitive to the variation of the solar flux and geomagnetic activity. USER NEEDS : thermospheric model for precise satellite orbitography  F10.7 & Kp indices are daily monitored and predicted (48h) at the “Solar Forecast Center” originally implemented at the Paris Observatory and now operated by CLS. The previsionist team is composed of 6 persons who update a solar bulletin before 14h UTC. The activity is done 365 days a year. Users : GFZ, ourselves (ARGOS orbit)  A working group on thermosphere has been formed in order to improve the actual DTM model: -CNES/GRGS : the model itself -LATMOS & CLS : computation of new magnetic proxies with better time/space resolution (15-30 min interval, representative of energy embedded). Proxies will be integrated in ISGI website. -LPCE : new solar indices (MgII, …) -LPG : thermospheric response to excitation ESWW6, Bruges, 16 nov. 2009

Page 9 Solar and geomagnetic indices ESWW6, Bruges, 16 nov Nov. 8-10, 2004 MAGNETIC STORM (Kp = 9) Same long-term behavior of the 30’ proxies w.r.t. the classical am index, with better time resolution.

Page 10 Summary -Ionospheric scintillations -Solar and geomagnetic indices -Solar Energetic Particle Events ESWW6, Bruges, 16 nov. 2009

Page 11 Solar Energetic Particle Events Very high energetic particles from solar flares may affect electronics embarked on space instruments. Eg: during the 6 months 2008 ATV mission, some operations were critical such as the ISS approach phases and the final docking and demanded a complete reliability of any component and system: processors, memories, navigation tools… USER NEEDS : integrity of the on-board electronics (satellites, vehicle (ATV), launchers)  A service, which gives the level of risk of a SEPE within 48h, has been developed at CLS in collaboration with the Paris Obs. /LESIA and the CPTh/X. Every day, an operator analyses the sun looking for precursors or indicators of SEPEs. They may be related to active regions morphology, position on the solar disk, magnetic complexity and to associated electromagnetic activities (radio burst…). The application of the method with numerical criteria over the last solar cycle has shown encouraging statistics in terms of SEPE detection. In addition, a complementary and necessary human analysis permits to limit false alerts. Future improvements are expected, related to the so-called confined characteristics of solar flares (K.L. Klein, Paris Obs.) ESA and CNES have used this CLS service for the ATV mission. ESWW6, Bruges, 16 nov. 2009

Page 12 Solar Energetic Particle Events ESWW6, Bruges, 16 nov SEPE may also occur during cycle minimum. Ex. 1985,1986,2006. (but we’re now in a real deep min.!)

Page 13 Solar Energetic Particle Events ESWW6, Bruges, 16 nov EXAMPLE OF A WEEKLY SYNOPTIC : small variations of proton fluxes Type II or IV radio bursts every day Favorable longitude for the first SEPE. Effect of flare “chain reaction” for the 2 nd one ?

Page 14 Solar Energetic Particle Events ESWW6, Bruges, 16 nov Simultaneous image of the Sun : From STEREO/B on :06From SOHO/EIT on :00 Future AR #11026 is observed more than 3 days before its apparition on Earth side (on Sept. 21st) This AR will provoke a C2 flare on Sept. 25th. Far side informations : STEREO + images & data from : - SOHO/SWAN - Helioseismology

Page 15 Solar Energetic Particle Events ESWW6, Bruges, 16 nov Performances : Numerical criteria applied on cycle 23 : - While looking for SEPE over 10 pfu for >50 MeV protons, 18 out of 34 SEPE were subject to an alert 24 h before the event. False alert : 30% - While looking for SEPE over 200 pfu for >50 MeV protons, 8 out of 10 SEPE were subject to an alert 24 h before the event. False alert : 5% The operator analysis limits the false alert rate.

Page 16 Conclusions ESWW6, Bruges, 16 nov Space weather activities in wide ranges of applications Promising results are expected in all domains - short term prediction of ionospheric scintillations - improvement of DTM model - refine precursors of SEPE Strength : - scientific collaboration - know-how in operational activities  Helping users to prepare for the next solar maximum