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Dieter Bilitza GSFC, Code 672, Greenbelt, Maryland and George Mason University, Virginia

International Reference Ionosphere and the Polar Ionosphere. Dieter Bilitza GSFC, Code 672, Greenbelt, Maryland and George Mason University, Virginia . Introduction and Current Status Polar Ionosphere Auroral Characteristics from TIMED/GUVI IRI-2007 and some Applications.

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Dieter Bilitza GSFC, Code 672, Greenbelt, Maryland and George Mason University, Virginia

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  1. International Reference Ionosphere and the Polar Ionosphere Dieter Bilitza GSFC, Code 672, Greenbelt, Maryland and George Mason University, Virginia • Introduction and Current Status • Polar Ionosphere • Auroral Characteristics from TIMED/GUVI • IRI-2007 and some Applications http://IRI.gsfc.nasa.gov

  2. INTERNATIONAL REFERENCE IONOSPHERE (IRI) Terms of Reference • The IRI Working Group was established to develop and improve a reference model for the most important plasma parameters in the Earth ionosphere. • IRI is a joint project of COSPAR and URSI. • COSPAR’s (Committee on Space Research) prime interest is in a general description of the ionosphere as part of the terrestrial environment for the evaluation of environmental effects on spacecraft and experiments in space. • URSI’s (International Union of Radioscience) prime interest is in the electron density part of IRI for defining the background ionosphere for radiowave propagation studies and applications. • The model should be primarily based on experimental evidence using all available ground and space data sources and should not depend on the evolving theoretical understanding of ionospheric processes. But theoretical considerations can help to find the appropriate mathematical functions, to bridge data gaps and for internal consistency checks. • As new data become available and as older data sources are fully evaluated and exploited, the model should be revised in accordance with these new results. • Where discrepancies exist between different data sources the IRI team should facilitate critical discussions to determine the reliability of the different data bases and to establish guidelines on which data should be used for ionospheric modeling. http://IRI.gsfc.nasa.gov

  3. P. Bradley, M. Rycroft, Lj. Cander (U.K.), K. Rawer, W. Singer (Germany), A. Alcayde, R. Hanbaba (France), B. Zolesi, S. Radicella (Italy), M. Friedrich (Austria), E. Kopp (Switzerland), D. Altadill (Spain) L. Triskova, V. Truhlik (Czech Rep) I. Kutiev (Bulgaria) I. Stanislawska (Poland), S. Kouris (Greece) A. Danilov V. K. Depuev T. Gulyaeva G. Ivanov-Kholodny K. Ratovsky A. Mikhailov B. Reinisch D. Bilitza T. Fuller-Rowell K. Bibl X. Huang J. Sojka D. Anderson V. Wickwar L. Scherliess M. Codrescu S-R Zhang C. Mertens K. Oyama K. Igarashi S. Watanabe W. Weixang M.-L. Zhang S.-Y. Su Kyoung Min S. Pulinets M. Abdu K. Mahajan S.P. Gupta P.K. Bhuyan O. Obrou P. Wilkinson P. Dyson B. Ward R. Ezquer M. Mosert de Gonzalez A. Poole, L.-A. McKinnell J. Adeniyi IRI Working Group Members http://IRI.gsfc.nasa.gov

  4. Paris, France 2004 C4.2 Advances in Specifying Plasma Temperatures and Ion Composition in the Ionosphere Volume 37 Issue 5 2006 2005 Ebro, Spain New Satellite and Ground Data for IRI and Comparisons with Regional Models Volume 39 Issue 5 2007 C4.2 - Solar activity variations of ionospheric parameters. 2006 In press New Data for Improved IRI TEC representation Oct 16-20 2007 IRI/COST Workshop: Ionosphere – Modeling, Forcing and Telecommunications, In pre-paration Prague, Czech Republic COSPAR GA, Montreal, Canada, July 13-20 C4.2 - Updating IRI with ground and space data 2008 URSI GA, Chicago, August 9-16 G02 – Density Profiling and Models http://IRI.gsfc.nasa.gov

  5. International Reference Ionosphere Monthly averages in the altitude range 50-1500 km: + Electron density + Electron temperature + Ion composition (O+, O2+, NO+, Cluster+, N+, He+, H+) [charge neutrality: Ne = ∑ni ] + Ion temperature + Ion drift (currently only equatorial vertical F-region drift) + spread-F occurrence probability (currently limited to South-American sector) http://IRI.gsfc.nasa.gov

  6. Data Sources Instrument Platform Used for Comments Ionosondes Worldwide Ne from E Fifties to Network to F2 now Incoherent Jicamarca, Ne profile Few radars, Scatter Arecibo, (E- valley) many Radar St. Santin, Te, Ti parameters MillstoneH., Malvern, Topside Alouette 1, 2 Ne topside newer data Sounder ISIS 1, 2 profile from Ohzora, ISS-b, IK-19 Insitu AE-C,-D,-E Ne topside many more: Aeros-A,-B profile,Te,Ti, DMSP, OGO IK-24, DE-2 ion comp. Hinotori Rocket data Ne D-region, sparse compilations Ion comp. data set http://IRI.gsfc.nasa.gov

  7. Build-up of IRI electron density profile Mathematical functions: Global Variations: Spherical harmonics, special functions Time Variations: Fourier, simple sin/cos, step-functions Height Variations: Epstein functions Normalized to E and F peaks Global models for foF2/NmF2, foF1/NmF1, foE/NmE hmF2/M(3000)F2, hmF1 , hmE http://IRI.gsfc.nasa.gov

  8. Ionosonde stations represented on NGDC CD-ROM Digisonde stations http://IRI.gsfc.nasa.gov

  9. Middle and Low Latitudes: Good data foundation; Well tested and evaluated; Good description of variations with height, latitude, longitude, local time/solar zenith angle, season/month, solar and magnetic activity; Now considered the standard (ISO and ECSS). High Latitudes (auroral, polar): Sparse data record; Only few modeling efforts; Need to consider dependence on IMF and magnetospheric magnetic field; Highly variable; Modeling needs to include representation of many special features, like troughs, ovals, holes, crests (density/temperature enhancements and depletions); IRI provides background ionosphere based on few high-latitude ionosondes; Modeling of auroral and polar ionosphere http://IRI.gsfc.nasa.gov

  10. Auroral and Polar Ionosphere • The solar wind, consisting mainly of protons and electrons moving at ultra-sonic speeds of 400 - 800 km/s (more than a million miles per hour). • The solar wind pressure strongly compresses the Earth’s magnetosphere on the dayside and draws it out into an extremely long tail on the nightside. • Electrons out of the solar wind are able to diffuse into magnetospheric tail and form a reservoir called the plasma sheet. The magnetosphere and the solar wind form an enormous electrical dynamo including one component which carries electrons down magnetic field lines where eventually they collide with the atmospheric gas causing it to glow. • On the dayside solar wind particles have direct access to the Earth's atmosphere via the cusp regions. Cusp Cusp http://IRI.gsfc.nasa.gov

  11. Oval latitudes span Fairbanks, Alaska, Oslo, Norway, and the Northwest Territories. A glowing band loops around the southern polar region in the distance as viewed by astronauts onboard the space shuttle. Polar VIS http://IRI.gsfc.nasa.gov

  12. Each oval consists of a band of auroral glow within which are embedded visible auroral arcs, bands and other shapes. The two auroral ovals pivot around the earth's geomagnetic poles, located near Thule, Greenland and Vostok, Antarctica. They are displaced somewhat toward the nightside of the earth with the consequence being that the ovals extend to lower latitude at night than they do in daytime. When conditions in the solar wind blowing out from the sun to the earth are quiet, the auroral ovals contract poleward and become quite narrow. During active conditions the ovals enlarge in diameter and widen. On rare occasions the northern oval may expand to reach southern California; likewise, the southern oval will expand toward the equator, simultaneously. Kp=4 http://IRI.gsfc.nasa.gov

  13. Rotkaehl et al., 2007 http://IRI.gsfc.nasa.gov

  14. http://IRI.gsfc.nasa.gov

  15. IRI - Data Comparisons http://IRI.gsfc.nasa.gov

  16. Mosert, Prague 2007: Antarctic ionosonde at San Martín (68.1°S; 293.0°E geographic; 53° S magnetic), 1996 (Rz=9.1) http://IRI.gsfc.nasa.gov

  17. Belgrano (77.9°S, 321.4°E geographic; 67.5° magnetic), 2000 (Rz= 117) http://IRI.gsfc.nasa.gov Figure 13

  18. Friedrich and Fankhauser, Prague, 2007: EISCAT Svalbard, 78°N, L = 15.5 300,000 profiles, 1997-03-11 to 2003-09-26 local model EISCAT Data NmF2 IRI hmF2 midnight noon ► IRI-foF2, extrapolated to 79°N, is not sensible http://IRI.gsfc.nasa.gov

  19. IRI - 2007 http://IRI.gsfc.nasa.gov

  20. Model for Ne in auroral lower ionosphere [McKinnell and Friedrich, Adv. Space Res., 37(5), 2006] ● NeuralNet model trained with ~700,000 EISCAT radar data points and 115 rocket profiles ●NN input space: local magnetic time (LMT), total absorption (Li), local magnetic index (K), solar zenith angle, F10.7 cm solar radio flux, pressure surface (p) (season, altitude) http://IRI.gsfc.nasa.gov

  21. Year = 2002, Day = 182, Hr = 23.93 UT, ZA = 87° http://IRI.gsfc.nasa.gov

  22. Year = 1984, Day = 332, Hr = 3.42 UT, ZA = 117° http://IRI.gsfc.nasa.gov

  23. IRI – New Developments http://IRI.gsfc.nasa.gov

  24. Inclusion of Auroral Boundaries in IRI Authors Instrument Parameterization Image data: Feldstein and Starkov [1967] IGY All sky imager Q = 0, 1, 2, 3, 4, 5, 6 Holzworth and Meng [1975] Mathematical representation of Feldstein-ovals in MLT, CGM, Q Carbary [2005] Polar UVI MLT, CGM, Kp Zhang and Paxton [2007] TIMED/GUVI MLT, CGM, Kp (energy flux, mean energy) Particle data:Energy flux and mean energy Wallis and Budzinski [1981] ISIS-2 MLT, InvLat, quiet and active Spiro, Reiff, Maher [1982] AE-C, -D MLT, InvLat, 4 levels of mag activity (AE) Hardy, Gussenhoven et al. [1987] DMSP MLT, CGM, 7 levels (Kp) Fuller-Rowell and Evans [1987] NOAA/TIROS MLT, MagLat, Hemispheric power input PEM-2004 (see Cai et al. [2007]) FAST, EISCAT MLT, ILAT, AE Electric field data:High-latitude convection pattern Heelis, Lowell, Spiro [1982] AE-C, -D ion drift data MLT, only for Bz southward Heppner and Maynard [1987] OGO-6, DE-2 MLT, CGM, IMF-Bz, Kp Rich and Maynard [1989] One of the agreements among these models is that soft electrons are dominant in the cusp region around magnetic midday. http://IRI.gsfc.nasa.gov

  25. Energy flux Mean energy Maps of estimated electron energy flux (a) and mean energy (b) using GUVI data for orbit 00900 on February 6, 2002. The grid size is 30x30 km. The red and green lines with arrows are for the tracks of TIMED and DMSP F14. The tip of the arrow indicate the location of TIMED and DMSP F14 at 12:43:27 UT. (c) and (d): Comparison between results from GUVI and DMSP F14 along the DMSP F14 track. The two blue vertical lines indicate the region where the DMSP F14 electron energy flux is above 1.0 erg/(cm2-s). http://IRI.gsfc.nasa.gov

  26. GUVI auroral models based on four years (2002-2005) of data and organized by magnetic latitude (Mlat), magnetic local time (MLT), and Kp (0-10). Modeled electron energy flux (left panels) and mean energy (right panels) at four Kp values: 1, 3,5 and 7. The white circles are for magnetic latitudes. The red lines are for the equatorward and poleward boundaries of the oval at a fixed flux 0.25 ergs/(cm2 s). The yellow numbers are magnetic local time. http://IRI.gsfc.nasa.gov

  27. Nightside auroral boundaries (equatorward: black line, poleward: red line) and nightside peak electron flux location (green line) versus Kp. http://IRI.gsfc.nasa.gov

  28. Left panel: DMSP F16 SSUSI auroral image over Greenland. The white bar over intense aurora (indicated by a solid red arrow) shows scan track of the Sondrestrom Incoherent Scatter Radar. Right: NmE, hmE along the white bar deduced from SSUSI UV measurements (blue line) and the radar NmE, hmE (red line). http://IRI.gsfc.nasa.gov

  29. Global map of IRI peak E-region electron density NmE for July 2004 at 14:00 UTC [Solomon, 2006]. Contribution from precepetating electrons at high latitudes not yet included. http://IRI.gsfc.nasa.gov

  30. Krankowski et al., 2007: GPS-deduced trough location Dependence on geomagnetic activity December 1999 http://IRI.gsfc.nasa.gov

  31. IRI – Future Plans for High Latitudes: • Inclusion of Auroral Characteristics: • - Auroral Boundaries • - Auroral NmE and hmE models including • contribution from precipitating electrons • - Representation of mid-latitude trough • Electron temperature enhancement • Effort would benefit from input of Barrow GPS and ionosonde data. http://IRI.gsfc.nasa.gov

  32. THANK YOU http://IRI.gsfc.nasa.gov

  33. New models for topside electron density IMAZ model for auroral Lower Ionosphere IRI-2007 New model for topside ion composition Equatorial disturbance ion drift model Spread-F occurrence probability model (Brazilian sector) Akebono model for electron temperature in plasmasphere http://IRI.gsfc.nasa.gov

  34. Fig. 9. Ionization production rate caused by precipitating electrons with energies ranging from 100 to 1000 eV. (From Millward et al., 1999). http://IRI.gsfc.nasa.gov

  35. Applications and Usage http://IRI.gsfc.nasa.gov

  36. Rios et al., JASTP, 2007, Tucuman Digisonde, Near Crest of Equatorial Anomaly foF2 / MHz hmF2 / km LT /hour • - - IRI/URSI • Ionosonde LT /hour http://IRI.gsfc.nasa.gov

  37. Chau and Woodman JGR, Dec 2005 Friedrich et al. GRL, April 2006 140 120 Altitude/km 100 80 Jicamarca measurements 60 Rocket (NASA EQUIS-II), 20 Sep 2004, near ALTAIR radar on Kwajalein Atoll (9N, 187E), 11:30 LST, SZA=19.7, Apogee = 131.2 km, F10.7= 101. Comparison of Ne from nosetip probe, wave propagation experiment, ALTAIR, and the models IRI and FIRI. First Jicamarca D and E region density measure- ments (13 Dec 2004, 11 LT) and comparison with IRI. http://IRI.gsfc.nasa.gov

  38. Comparison with KOMPSAT Kim et al., JASTP, 2006 Comparison of KOMPSAT-1 Te measure- ments in the low-latitude nighttime at 685 km with the two IRI Te options. Newer option (Intercosmos) shows better agreement. Te-Intercosmos Te-ISIS, Aeros http://IRI.gsfc.nasa.gov

  39. STANDARD FOR ENGINEERING APPLICATIONS • IRI is used as the standard in “Natural Orbital Environment Definition Guidelines for Use in Aerospace Vehicle Development” [NASA Tech Memo., NASA-TM-4527, 1994]. • IRI is the standard ionospheric model in “System Engineering – Space Environment” handbook of the European Cooperation for Space Standardization [ECSS, 1997]. • IRI was recognized as the international standard for the ionosphere in an official Commission G Resolution during the 1999 International Union of Radio Science (URSI) General Assembly. • IRI is recommended by the International Telecommunication Union (ITU) for the computation of retardation effects on radio waves traveling through the ionosphere. • IRI is the ionospheric model proposed in TS 16457 of the International Standardization Organization (ISO). http://IRI.gsfc.nasa.gov

  40. VISUALIZATION AND ONLINE TOOLS FOR SPACE ENVIRONMENT PARAMETERS • Current time global NmF2, hmF2, and TEC IRI maps (S.-R. Zhang, MIT): http://madrigal.haystack.mit.edu/models/IRI/index.html • Real-time maps of IRI TEC for Australiasia, North America, Europe, and Japan (IPS, Sydney, Australia): http://www.ips.gov.au/Satellite/2/1 • Computation of ionospheric conductivities using IRI and CIRA (WDC Kyoto, Japan): http://swdcwww.kugi.kyoto-u.ac.jp/ionocond/index.html • MPEG movies of global maps of IRI density and temperature at the Space Environments Branch of NASA Glenn Research Center: http://powerweb.grc.nasa.gov/pvsee/info/movies/iri90.html • The SPace ENVironment Information System (SPENVIS) developed at the Belgian Institute for Space Aeronomy for ESA/ESTEChttp://www.spenvis.oma.be/spenvis/ • IRIWeb for online computation and plotting of IRI parameters developed at NASA/GSFC NSSDC/SPDF http://modelweb.gsfc.nasa.gov/models/iri.html 3-d electron density visualization using AVS (CRL, Tokyo, Japan ) http://IRI.gsfc.nasa.gov

  41. foF2 UT: 0 - 24 foF2 LT: 0 - 24 hmF2 UT: 0 - 24 log(Ne) UT: 0 - 24 http://IRI.gsfc.nasa.gov

  42. BACKGROUND IONOSPHERE FOR EVALUATING DATA RETRIEVAL TECHNIQUES • Testing algorithms that convert GPS measurements into global TEC maps (Hernandez-Pajares et al., 2002) • TEC from NNSS Doppler measurements (Ciraolo and Spalla, 2002) • Reliability of tomographic methods (Bust et al., 2004). • Testing algorithm for GPS/MET occultation measurements (Tsai et al., JASTP, submitted; Hocke and Igarashi, 2002) • Developing data analysis algorithm for retrieval of electron densities from TIMED/GUVI airglow measurements (DeMajistre et al., 2004) http://IRI.gsfc.nasa.gov

  43. IONOSPHERIC CORRECTIONS FOR SINGLE-FREQUENCY ALTIMETRY • Pathfinder Project: Longtime data record of sea surface heights; updating IRI with ionosonde data (Bilitza, Bhardwaj and Koblinsky, 1997; Lillibridge and Cheney, 1997) • ERS Quick-look data (ERS Products User Manual, 1996) • Work with Geosat Follow On (GFO) data (Zhao et al., 2002. http://IRI.gsfc.nasa.gov

  44. IONOSPHERIC PARAMETERS FOR THEORETICAL MODELS Comprehensive Ring Current Model (CRCM) [Ebihara, et al., 2004, 2005] Ionospheric Conductances for Rice Convection Model (RCM) [DeZeeuw et al. 2004] Baseline against which the predictive skills of physics-based models are compared [Siscoe et al., 2004] http://IRI.gsfc.nasa.gov

  45. IRI Usage Statistics JGR/GRL/RS/JSTP/AG papers using IRI 2005: 51 2006: 54 IRI ftp site downloads ~5,000/month IRIweb online accesses ~4,000/month Dec06: 6,058 Nov06: 4,772 Apr07: 4,470 May07:4,241 http://IRI.gsfc.nasa.gov

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