1. Dario Sabbagh (1),(2), Carlo Scotto (2), Vittorio Sgrigna (1) (1) Università degli Studi Roma Tre, Dipartimento di Matematica e Fisica, Via della Vasca Navale 84, I-00146 Roma, Italy (2) Istituto Nazionale di Geofisica e Vulcanologia, Via di Vigna Murata 605, I-00143 Roma, Italy April 19, 2016 Good afternoon, I am Dario Sabbagh and I’m a PhD student from Roma Tre University and Istituto Nazionale di Geofisica e Vulcanologia in Rome.

2. Outline AUSPICIO project Data set Some interesting ionograms Firstly, I will introduce AUSPICIO project, which is the frame of this work. I will show to you the polar ionograms data set used Then, I will show an empirical correction to this formulation proposed at a particular station,

3. AUSPICIO is the acronym of Automatic Scaling of Polar Ionograms and Cooperative Ionospheric Observations. It is a project funded by the Italian National Program for Research in Antarctica and carried out by the Istituto Nazionale di Geofisica e Vulcanologia and the International Centre for Theoretical Physics. The main task of the project is to achieve improvements to Autoscala software for application in polar regions, [in order to let polar ionospheric stations to make a reliable automatic interpretation of vertical ionograms,] as the automatic scaling of the ionograms is an essential function of modern ionospheric observatories in order to feed real time models. To do so, AUSPICIO project uses ionogram samples provided by international institutions, such as the Australian SWS, the Brazilian INPE, the Spanish Ramon Lull University, and the Italian INGV. AUSPICIO project Automatic Scaling of Polar Ionograms and Cooperative Ionospheric Observations improvements to Autoscala for application in polar regions PNRA funded project carried out by INGV and ICTP Task … using ionogram samples provided by international institutions:

4. Data set Hobart Macquarie Isl. Camandante Ferraz Livingston Isl. Davis Mawson Casey Scott Base Mario Zucchelli Station Total ionograms: 5 ∙ 556 576 588 647 720 771 1 ∙ 313 556 217 168 from 2001 to 2014 Solar activity In this map is shown the location of the ionospheric stations involved in the project, with the number of ionograms used in this work These stations are all in the Antarctica area and are, in particular […]. The total number of ionograms used in this work is about five thousand and and five hundred, No other station has ionograms recorded during this year. medium (eg: 2003 for MZS) recorded in periods of high, low and medium solar activity. In particular, for most of the stations there are 2001 and 2009 ionograms, associated with very high and very low solar activity. A special case is Mario Zucchelli station, for wich we have used only data recorded in November 2003, associated with medium- high solar activity.

5. Comparison for: histograms with classes defined by d intervals of o.o5 MHz with all data stations separately The comparison has been made for the entire data set and for each station separately. For this purpose we have computed the root mean square deviations between the observed and modeled values, and we have produced frequency histograms with classes defined by deviation intervals of o.o5 MHz

6. … … DuCharme underestimation DuCharme overestimation All data 2 peaks overall underestimation Classes inhomogeneous database 2001: high solar activity 2009: low solar activity This is the histogram made considering all available data. The mean deviation is -0.22 MHz and the root mean square deviation between the four hundred seventy-six couples of values is 0.35. As we can see, the histogram has 2 distinct peaks. This could be related to the inhomogeneity of the data set. Infact most of the ionograms whose deviation belongs to the class 21 (which is associated to the main peak) are 2009 ionograms, and most of the ionograms whose deviation belongs to the class 14 (associated to the secondary peak) have been recorded in 2001.

7. Stations separately Macquarie Isl. Mario Zucchelli Station Casey Com. Ferraz Davies Hobart Livingston Isl. Scott Base Mawson DuCharme underestimation in all stations inhomogeneous database In these pictures are shown the same histograms for each station separately. Except for Scott Base, at stations where there are about seventy couples of values or more, we can see a double peak similar to the peaks observed considering all data. This is in line with what already said about the inomogeinity of the data set. So, why do we see such a double peak in the distribution? Considering the geomagnetic activity during November 2003 we know that during November the 20 th a strong geomagnetic storm occurred. storm days A special case is Mario Zucchelli Station, for which the data set is homogeneous in solar activity.

8. Based on this study a correction to the DuCharme and Petrie formula is proposed. Where? particular station at polar regions performance of a procedure for detecting spread-F improved version of Autoscala (poster presentation, C. Scotto, A. Ippolito) Macquarie Island Receiver Operating Characteristic (ROC) curve method This correction is performed to be implemented in an improved version of Autoscala software for a particular ionospheric station, in the frame of AUSPICIO project. This station could be chosen evaluating the performance of a procedure for detecting ionograms affected by spread-F. This routine has been separately developed, implemented in Autoscala program, and applied to the ionograms belonging to the same data set used in this work (there is a poster on this topic). Accordingly to the assessment of such performance based on the ROC curve method, the station at Macquarie Island could be a good candidate.

9. How?original DuCharme and Petrie formulation (1973): with where 1.Definition of the parameters Considering the geomagnetic latitude value at Macquarie Island, these are the values of the parameters associated with the original DuCharm and Petrie formulation. So, we can call them «base» values.

10. After their definition, we let these parameters to vary within a proper interval around these «base» values This procedure has led us to fix the values of these parameters in this way. This is a first proposal for a particular station, but further studies could let us to develop a generalized formulation. with

11. … … Classes … single peak As we can see, the root mean square deviation between these values and the observed ones is lower in the latter case, for which there is no understimation. Furthermore, in this case the effect of the inhomogeneity of the data set is removed, as we see a single peak near the classes associated with very little deviations.

12. Conclusions Polar ionograms data set analysis In conclusion, we have analyzed a limited data set of vertical ionograms recorded in several international polar stations, in the frame of AUSPICIO project. So, we propose an empirical correction to this formulation to be implemented in an improved version of Autoscala software for Macquarie Island station, developed varying some formula parameters in order to minimize the root mean square deviations between observed and modeled values. This improved formulation proposed at Macquarie Island shows a good behaviour and could be generalized at polar regions through a further study which could consider a wider data set, solar activity and geomagnetic activity. Further study generalization at polar regions wider data set solar activity geomagnetic activity

13. Multiple reflections Davis Mario Zucchelli Station Z-ray Macquarie Island Tilted ionosphere For example in this ionogam we can cleary see multiple reflections. while in this one there is a trace that coul be associated with a Z ray, which is a peculiar polar ionospheric phenomenon. Another interesting feature is a doubling of the trace associated with reflections from different directions. This could be related to the presence of a tilted ionosphere. Some interesting ionograms

14. Double stratification + tilted ionosphere Double stratification Macquarie Island Livingston Island In the ionogram on the bottom we can see also a doubling of the trace after the second cusp, maybe associated with a tilted ionosphere. Some interesting ionograms

15. Thank you for your attention Acknowledgements Space Weather Service (SWS, Australia) for providing the ionograms database at Hobart, Macquarie Island, Casey, Mawson, Davis, and Scott Base Istituto Nacional de Pesquisas Espaciais (INPE, Brasil) for providing the ionograms at Comandante Ferraz Universitat Ramon Lull (Spain) for providing the ionograms at Livingstone Island Progetto Nazionale Ricerche in Antartide (PNRA) to have supported this study