Data ingestion into NeQuick 2 B. Nava, 1 S. M. Radicella, 1 and F. Azpilicueta 2,3 Received 31 December 2010; revised 2 June 2011; accepted 9 June 2011; published 21 September 2011. [1] NeQuick 2 is the latest version of the NeQuick ionosphere electron density model developed at the Aeronomy and Radiopropagation Laboratory of the Abdus Salam International Centre for Theoretical Physics (ICTP) ‐ Trieste, Italy with the collaboration of the Institute for Geophysics, Astrophysics and Meteorology of the University of Graz, Austria. It is a quick‐run model particularly designed for trans‐ionospheric propagation applications that has been conceived to reproduce the median behavior of the ionosphere. To provide 3‐D specification of the ionosphere electron density for current conditions, different ionosphere electron density retrieval techniques based on the NeQuick adaptation to GPS‐derived Total Electron Content (TEC) data and ionosonde measured peak parameters values have been developed. In the present paper the technique based on the ingestion of global vertical TEC map into NeQuick 2 will be validated and an assessment of the capability of the model to reproduce the ionosphere day‐to‐day variability will also be performed. For this purpose hourly GPS‐derived global vertical TEC maps and hourly foF2 values from about 20 ionosondes corresponding to one month in high solar activity and one month in low solar activity period will be used. Furthermore, the first results concerning the ingestion of space‐based GPS‐derived TEC data will be presented. Citation: Nava, B., S. M. Radicella, and F. Azpilicueta (2011), Data ingestion into NeQuick 2, Radio Sci., 46, RS0D17, doi:10.1029/2010RS004635. 1. Introduction [2] Empirical models like IRI [Bilitza, 2001; Bilitza and Reinisch, 2008] and NeQuick [Hochegger et al., 2000; Nava et al., 2008] have been developed as climatological models, able to reproduce the typical median condition of the ionosphere. In order to pass from ionosphere “climate” to “weather” there is a need to have models able to repro- duce the current conditions of the ionosphere. Indeed, sev- eral assimilation schemes (e.g. Utah State University (USU) Global Assimilation of Ionospheric Measurements (GAIM) [Schunk et al., 2004], Jet Propulsion Laboratory (JPL)/ University of Southern California (USC) Global Assimila- tive Ionospheric Model (GAIM) [Wang et al., 2004], Elec- tron Density Assimilative Model (EDAM) [Angling and Khattatov, 2006]) have been developed for this purpose: they are of different complexity and rely on diverse kinds of background models and data. In the case of NeQuick, the needs of simplicity and speed behind the genesis of the model led to the implementation of electron density retrieval techniques relying on the use of “effective” parameters, that are defined on the bases of the model and the experimental data considered. In particular, following the ideas expressed by Komjathy et al. [1998] and by Hernandez‐Pajares et al. [2002], different methods to adapt the NeQuick to vertical TEC maps [Nava et al., 2005] or to ground‐based GPS‐ derived TEC data [Nava et al., 2006] have been developed and their effectiveness has been demonstrated considering the first version of the NeQuick model. In the present paper the ingestion technique based on NeQuick 2 adaptation to global vertical TEC maps will be validated. For this purpose hourly global vertical TEC maps and manually scaled hourly foF2 values from about 20 ionosondes corresponding to one month in high solar activity and one month in low solar activity period will be used. The performance of NeQuick 2 in reconstructing the 3D electron density of the ionosphere will be analyzed in terms of statistical comparisons between experimental and retrieved critical frequencies of the F2 layer. In addition, an assessment of the capability of the model to reproduce the ionosphere day‐to‐day variability will also be performed by means of a complete analysis concerning the foF2 monthly median values and the inter‐decile range of the difference between the experimental and the reconstructed foF2. [3] Finally, the first results concerning the NeQuick 2 model adaptation to Radio Occultation (RO)‐derived TEC measurements will be presented. 2. Data Ingestion Into NeQuick 2 [4] In the present work we consider “data ingestion into NeQuick” to be synonymous with “NeQuick adaptation to a given set of experimental data”, where the experimental data are usually GPS‐derived TEC and/or ionosonde‐derived 1 Aeronomy and Radiopropagation Laboratory, Abdus Salam International Centre for Theoretical Physics, Trieste, Italy. 2 Facultad de Ciencias Astronómicas y Geofísicas, Universidad Nacional de La Plata, La Plata, Argentina. 3 CONICET, Buenos Aires, Argentina. Copyright 2011 by the American Geophysical Union. 0048‐6604/11/2010RS004635 RADIO SCIENCE, VOL. 46, RS0D17, doi:10.1029/2010RS004635, 2011 RS0D17 1 of 8