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PRELIMINARY UPC VTEC FORECAST
MODEL BASED ON IGS GIMs
A. Ga cía-Rigo1, E. Mon e2, M. He nández-Paja es1,
J.M. Juan1, J. Sanz1 and R. O ús1,3
Resea ch g oup o As onomy & Geoma ics (gAGE/UPC), Ba celona, Spain
Dep . o Signal Theo y & Communica ions (TSC/UPC), Ba celona, Spain
Wa e In e ac ion & P opaga ion Sec ion (ESA-ESTEC), Noo dwijk,
Ne he lands.
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•In oduc ion o IGS Global Ionosphe ic Maps
•P edic ion o IGS GIMs: UPC app oach
•Resul s
•Conclusions and u u e s eps
Sho Ou line
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•In oduc ion o IGS Global Ionosphe ic Maps
•P edic ion o IGS GIMs: UPC app oach
•Resul s
•Conclusions and u u e s eps
Sho Ou line
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IGS Global Ionosphe ic Maps
• The IGS Iono-WG was c ea ed in 1998 wi h he goal o gene a e
eliable e ical TEC Global Ionosphe ic Maps (GIMs) using IGS
ne wo k.
• Indi idual GIMs a e compu ed by he IAACs: CODE, ESA, JPL and
UPC.
• E alua ion and combina ion o c ea e he IGS global VTEC p oduc s
(IGSG and IGRG).
• All p oduc s in IONEX o ma , a 2h esolu ion and 2.5º/5º in longi ude/
la i ude esolu ion.
• La encies o 9-16 days o inal GIMs and 1-2 days o apid GIMs.
• Long ime se ies o GIMs a ailable.
• Mo e de ails can be ound o ins ance in He nández-Paja es e al.
2009.
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•In oduc ion o IGS Global Ionosphe ic Maps
•P edic ion o IGS GIMs: UPC app oach
•Resul s
•Conclusions and u u e s eps
Sho Ou line
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• Sho - e m VTEC p edic ion model de eloped in he ame o IGS
iono-WG.
• P elimina y 2-days ahead VTEC o ecas p oduc de eloped and
being au oma ically dis ibu ed h ough CDDIS FTP se e on a daily
basis.
• In e es o a wide a ie y o scien i ic and echnological applica ions.
• Mo eo e , a p elimina y combined p oduc wi h ESA o ecas p oduc
is being au oma ically gene a ed and dis ibu ed as well.
• Cu en UPC app oach based on aking long ime se ies o UPC
GIMs as inpu da a and he use o Linea Reg ession combined wi h
he Disc e e Cosine T ans o m (LRDCT me hod).
UPC p edic ion app oach
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• DCT coe icien s as e ical and ho izon al spa ial equency componen s.
• Spa ial in o ma ion o he whole image in each coe icien .
• Rep esen a ion o da a wi h a se o pa ame e s o a gene a i e model (DCT).
NxM samples a e gene a ed wi h a subse o Cp,q (lowe dimensional
ep esen a ion o he map)
• No e olu ion o a pixel bu o he equency componen s ha gene a e he
map (mo e obus ).
UPC p edic ion app oach
DCT image PxQ: C p, q
O iginal image MxN: χ m, n
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T aining
• The model is ained using a aining da ase o one yea o inal
(bes ) a ailable UPC GIMs (13 independen models pe day).
• E e y single GIM in he aining da ase is ans o med in a Sun ixed
e e ence ame using he DCT.
• A Linea Reg ession is applied o each o he DCT coe icien s → he
p edic ion is done on he DCT coe icien s.
whe e ω0 and ωu a e he eg ession coe icien s o be adjus ed wi h
he aining se .
• Adjus men by inding he ela ion be ween all he aining subse s o
se en days and hei co esponding known e e ence alues.
• Addi ional in o ma ion may be added so ha eg ession coe icien s
will also be adjus ed o i .
UPC p edic ion app oach
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P edic ion
• The model is applied o he model's inpu da ase , i.e. he a ailable
UPC GIMs o las se en days.
• E e y single GIM in he aining da ase is ans o med in a Sun ixed
e e ence ame using he DCT.
• Applying he adjus ed eg ession coe icien s o model's inpu se o
ob ain he DCT coe icien s ha will gene a e he p edic ed map.
• In e se DCT, and con e o longi ude/la i ude be o e encapsula ing in
IONEX o ma .
UPC p edic ion app oach
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BIAS
Valida ion wi h Final
UPCG GIMs
ST.DEV.
Las wo mon hs pe iod
90 – 149, 2010
0≤Kp≤7.7;meanKp=1.58
•UPCG sU2PG o e all RMS esul s show an RMS
imp o emen o 13.3 % wi h espec o UPCG sUPR2 .
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Ex e nal alida ion:
JASON VTEC
Las wo mon hs pe iod
90 – 149, 2010
ERROR % (RMS/meanVTEC)
BIAS
ST.DEV.
•U2PG o e all RMS esul s a e 17.4% wo se han UPCG
ones and UPC2 a e 24.7% wo se.
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gAGE Resea ch g oup o As onomy and GEoma ics 2010
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•In oduc ion o IGS Global Ionosphe ic Maps
•P edic ion o IGS GIMs: UPC app oach
•Resul s
•Conclusions and u u e s eps
Sho Ou line
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Conclusions & u u e s eps
• UPC cu en p edic ion model p o ides be e esul s o he selec ed
pe iods han non- a ian ionosphe e wi h simila esul s o p edic ed
global VTEC maps om o he IAACs.
• UPC o ecas p oduc gene a ed in es mode o mo e han one yea
wi hou majo p oblems.
• Mo ing om a p elimina o an o icial UPC IGS o ecas p oduc
seems easible in less han one yea .
Fu u e s eps
• Imp o emen o he LRDCT model unde di e en geomagne ic/sola
condi ions
• Compa ison wi h o he p edic ion me hods such as Neu al Ne wo ks.
• Assessmen on he use o di e en models o pa ame e s in unc ion
o he geomagne ic/sola ac i i y.
• Tes s wi h addi ional physical in o ma ion (Sola Flux, Kp, e c).
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Re e ences
Ahmed, N., T. Na a ajan and K.R. Rao (1974). “Disc e e Cosine T ans o m”, IEEE
T ans. Compu e s, pp.90-93, 1974.
Ga cía-Rigo, A., E. Mon e, M. He nández-Paja es, J.M. Juan, J. Sanz, A. K ankowski
and P. Wielgosz (2009). “P edic ion o Global Ionosphe ic TEC maps: Fi s esul s on a
UPC o ecas p oduc ” (Pos e ). Eu opean Gene al Assembly (EGU), Ap il 2009,
Vienna, Aus ia.
He nández-Paja es M., J.M. Juan, J. Sanz, R. O us, A. Ga cia-Rigo, J. Fel ens, A.
Komja hy, S.C. Schae , and A. K ankowski (2009): “The IGS VTEC maps: a eliable
sou ce o ionosphe ic in o ma ion since 1998”, Special IGS Issue o Jou nal o Geodesy,
83(3-4), 263-275, doi:10.1007/s00190-008-0266-1
R. O ús, M. He nández-Paja es, J.M. Juan, J. Sanz, A. A agón-Angel, A. Ga cía-Rigo
(2010). “Real Time Applica ion o TOMION Model“. Pos e in Beacon Sa elli e
Symposium, June 2010, Ba celona, Spain.
Acknowledgemen s
This s udy has been unded by he Spanish Minis y o Educa ion and Science in he
ame o ESP2004-05682-C02-01 p ojec , by he Eu opean Social Fund (g an
BES-2006-12741), as well as by he Spanish Minis y o Science and Technology in he
ame o ESP2007-62676 p ojec (IBER-WARTK).
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Thanks a lo !
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His og ams
