Radio Science Bulletin 313 - June 2005 - URSI

IRI 2005 WORKSHOPNEW SATELLITE AND GROUND DATA FOR IRI AND COMPARISONWITH REGIONAL MODELSRoquetes, Spain, 27 June - 1 July 2005As part of its centennial celebrations, the EbroObservatory in Roquetes, Spain, hosted the 2005International Reference Ionosphere (IRI) Workshop.Workshop sessions, held at the Observatory and the AuditoryFelip Pedrell in neighboring Tortosa from June 27 to July 1,covered the typical IRI topics: F-region Modeling,Bottomside Parameters and Drifts, Topside Ionosphere,IRI Applications, Temperature and Composition,Ionospheric Variability, Lower Ionosphere, Total ElectronContent, and New Inputs for IRI. The agenda included 66presentations by 48 scientists from 18 countries illustratingthe global reach and importance of the IRI activities.Ground and space data sources were evenly representedincluding data from many ionosondes, and from mostincoherent scatter radars, and from the satellites Akebono,CHAMP, DMSP, GPS, Hinotori, IK-19, IK-24, IMAGE,ISIS, JASON, Ohzora, ROCSAT, TIMED, TIROS/NOAA,and TOPEX, and from several rocket flights. The meetingbenefited from the excellent local support under theleadership of Dr. David Altadill. The Observatory team notonly patiently shepherded the international group of scientistsduring the session periods, but also arranged an eveningwalking tour of Tortosa and a conference excursion to thebeautiful Tortosa-Beseit Natural Park and the Picasso Centerin Orta de Sant Joan. Opening and closing ceremonies wereattended by local and regional politicians who pledged theirsupport for the Observatory and acknowledged theimportance of holding this international science meeting intheir town and region. Financial support was provided bythe following organizations: Committee on Space Research(COSPAR), International Union of Radio Science (URSI),European Office of Aerospace Research and Development(EOARD) of the US Air Force Office of Scientific Research,Consejo Superior de Investigaciones Cientificas (CSIC),Ministerio de Educación y Ciencia (MEC), Agència deGestió d’Ajuts Universitaris i de Recerca (AGAUR) and bythe Observatori de l’Ebre. Also the Mayor’s Offices of theTowns of Roquetes and Tortosa, the Council of the LowerEbro Area, La Caixa, the Ramon Llull University andDiario ABC supported this event.Electron Density :Topside,Plasmasphere, and TECThe new version of IRI, due to be released later thisyear, will include two options for the topside electrondensity: (1) the correction term for the current IRI model asproposed by Bilitza (USA) and (2) the newest version of theNeQuick model as presented by Coisson (Italy).Reinisch (USA) explained his new approach ofrepresenting the topside and plasmasphere electron densitiesby a Chapman profile with continuously varying scaleheightusing the developing UML plasmasphere model thatis based on IMAGE/RPI and ISIS measurements.Alternatively, Pulinets (Mexico) and Depuev (Russia) areproposing the use of an Epstein function with variablescale-height and have successfully applied this approach totheir IK-19 topside sounder data. An important aspect oftheir model is the inclusion of persistent longitudinal features.Uemoto (Japan) presented Ohzora and Akebono topsidesounder data as a possible source for improvements of theIRI topside profile. Plasmaspheric extensions of IRI werediscussed by Coisson (Italy) and by Gulyaeva (Russia)using the Global Core Plasma Model (GCPM) developedby Gallagher et al. (USA). Garner (USA) found that binnedDMSP data follow a lognormal distribution and he studiedglobal and solar activity variations of the distributionparameters.There were quite a number of presentations of TECrelatedstudies including: (1) Comparisons of GPS TECwith ionosonde ITEC measurements (McKinnell, SouthAfrica; Mosert, Argentina), (2) Comparisons of TECmeasurements with IRI predictions (Bhuyan, India; F.Arikan, Turkey; Moeketsi, South Africa; Opperman, SouthAfrica). (3) Ionospheric tomography techniques and theirutilization of IRI (O. Arikan, Turkey; Bhuyan, India;Opperman, South Africa), (4) Ionospheric data obtained bydifferent dual-frequency space techniques and their use forimprovements of IRI (Bilitza, USA), (5) An assessment of2 nd order ionospheric effects on GPS measurements(Hernandez-Pajares, Spain), (6) Using a wavelet/splineapproach as an initial step of a multi-resolution representationof TEC (Schmidt, Germany) (6) A method for deducingfoF2 from GPS-TEC (Krankowski, Poland).Electron Density : F-peakand belowThe main new input for the next version of IRI will bethe spread-F occurrence model for the South-Americansector that was developed by Abdu (Brazil) based onionosonde data. Efforts are under way to develop aquantitative description of ionospheric variability in termsof quartiles and deciles for inclusion in IRI (Mosert,Argentina; Altadill, Spain).TheRadio Science Bulletin No 313 (June, 2005) 81