The results of different algorithms for automatic detection of wave packets in geomagnetic records are compared: the approach based on the Fourier transform in a running time window F-method, and the approach based on discrete perfect set DPS analysis. Using 1-sec data from a mid-latitude INTERMAGNET station we determined with both algorithms such statistical properties of Pc3 geomagnetic pulsations in the frequency range 30--80 mHz as diurnal variations, frequency occurrence, amplitude probability distributions, etc. The diurnal distributions of the occurrence probability determined by both methods have a wide peak around noon hours and a small enhancement during nighttime hours. The advantage of the DPS analysis is the possibility to determine duration of a wave packet. This method shows that average duration of dayside wave packets is statistically longer than that of the nighttime events. Statistical distributions over power/amplitude can be used to infer some conclusions about physical mechanisms of signals. The distribution obtained with the F-method differs for two horizontal components: $H$ component distribution is vulnerable to the magnetospheric resonance effect and reveals parabolic dependence in log-log scale, whereas non-resonant $D$ component has a power-law distribution. The DPS-method provides almost exponential decay of probability with amplitude for both components. The difference between statistical results of two methods is probably caused by different dependences of detection sensitivity to signal amplitude.
geomagnetic pulsations, ionosphere, magnetosphere, automatic signal detection
1. Anderson, B. J., Engebretson, M. J., Rounds, S. P., et al. A statistical study of Pc 3#x2013;5 pulsations observed by the AMPTE/CCE Magnetic Fields Experiment, 1. Occurrence distributions, // JGR: Space Physics, 1990. - v. 95 - no. A7 - p. 10249.
2. Bier, E. A., Owusu, N., Engebretson, M. J., Posch, J. L., Lessard, M. R., Pilipenko, V. A. Investigating the IMF cone angle control of Pc3#x2013;4 pulsations observed on the ground, // JGR: Space Physics, 2014. - v. 119 - no. 3 - p. 1797.
3. Bogoutdinov, Sh. R., Yagova, N. V., Pilipenko, V. A., Agayan, S. M. Dataset of visually selected Pc3s - Moscow: ESDB, GC RAS., 2018.
4. Bortnik, J., Cutler, J. W., Dunson, C., Bleier, T. An automatic wave detection algorithm applied to Pc1 pulsations, // JGR: Space Physics, 2007. - v. 112 - no. A4 - p. A04204 1.
5. Chugunova, O., Pilipenko, V., Zastenker, G., et al. Magnetosheath turbulence and magnetospheric Pc3 pulsations - St. Petersburg: edited by V. N. Troyan, M. Hayakawa, and V. S. Semenov., 2008.
6. Clausen, L.B.N., Yeoman, T.K., Fear. C. R.C., et al. First simultaneous measurements of waves generated at the bow shock in the solar wind, the magnetosphere and on the ground, // Annales Geophysicae, 2009. - v. 27 - no. 1 - p. 357.
7. Engebretson, M.J., Lin, N., Baumjohann. W. R.C., et al. A comparison of ULF fluctuations in the solar wind, magnetosheath, and dayside magnetosphere: 1. Magnetosheath morphology, // JGR: Space Physics, 1991. - v. 96 - no. A3 - p. 3441.
8. Gudzenko, L.I. Statistical method to determine the characteristics of non-controlled auto-oscillatory system, // Radiophysics and Quantum Electronics, 1962. - v. 5 - no. 3 - p. 572.
9. Gugliel'mi, A.V. The coefficient of relationship between the Pc3 pulsation frequency and IMF magnitude, // Geomagnetism and Aeronomy, 1988. - no. 28 - p. 465.
10. Gugliel'mi, A.V., Potapov, A.S. Note on the dependence of Pc3#x2013;4 activity on the solar wind velocity, // Annales Geophysicae, 1994. - v. 12 - no. 12 - p. 1192.
11. Gugliel'mi, A.V., Troitskaya, V.A. Geomagnetic pulsations and diagnostics of the magnetosphere - Moscow: Nauka., 1973. - 206 pp.
12. Gvishiani, A., Lukianova, R., Soloviev, A., et al. Survey of geomagnetic observations made in Northern Russia and new methods for analyzing them, // Surveys Geophysics, 2014. - v. 35 - no. 5 - p. 1123.
13. Gvishiani, A.D., Lukianova, R.Y. Geoinformatics and observations of the Earth's magnetic field: the Russian segment, // Izvestiya-Physics of the Solid Earth, 2015. - v. 51 - no. 2 - p. 157.
14. Heilig, B., Lotz, S., Vero, J., Sutcliffe, P., Reda, J., Pajunpaa, K., Raita, T. Empirically modeled Pc3 activity based on solar wind parameters, // Annales Geophysicae, 2010. - v. 28 - no. 9 - p. 1703.
15. Kay, S.M. Modern spectral estimation: Theory and application - New Jersey, USA: Prentice-Hall., 1988. - 543 pp.
16. Kleimenova, N.G., Kozyreva, O.V., Malysheva, L.M., Zelinskii, N.R., Solov'ev, A.A., Bogoutdinov, S.R. Pc3 geomagnetic pulsations at near-equatorial latitudes at the initial phase of the magnetic storm of April 5, 2010, // Geomagnetism and Aeronomy, 2013. - v. 53 - no. 3 - p. 313.
17. Papadimitriou, C., Balasis, G., Daglis, I.A., et al. An initial ULF wave index derived from two years of Swarm observations, // Annales Geophysicae, 2018. - v. 36 - no. 2 - p. 287.
18. Parkhomov, V.A., Polyushkina, T. N., Stupin, V.V. The increase of geomagnetic pulsation activity in the Pc3 range during magnetospheric substorms, // Research in Geomagn., Aer. And Solar Physics, 1988. - v. 81 - p. 188.
19. Parkhomov, V.A., Stupin, V.V. Identification of geomagnetic pulsations simulation methods in the problems of magnetospheric diagnostics, // Geomagnetism and Aeronomy, 1990. - v. 30 - no. 1 - p. 44.
20. Parks, T.W., Burrus, C.S. Digital filter design - New York, USA: Wiley., 1987. - 342 pp.
21. Pilipenko, V., Yumoto, K., Fedorov, E., Yagova, N. Hydromagnetic spectroscopy of the magnetosphere with Pc3 geomagnetic pulsations at 210 meridian, // Geomagnetism and Aeronomy, 1999. - v. 17 - no. 1 - p. 53.
22. Pilipenko, V.A., Chugunova, O.M., Engebretson, M.J. Pc3#x2013;4 ULF waves at polar latitudes, // Journal of Atmospheric and Solar-Terrestrial Physics, 2008. - v. 70 - no. 18 - p. 2262.
23. Pilipenko, V.A., Kozyreva, O.V., Engebretson, M.J., Soloviev, A.A. ULF wave power index for the space weather and geophysical applications: A review, // Russ. J. Earth. Sci., 2017. - v. 17 - no. 2 - p. 2262.
24. Ponomarenko, P.V., Fraser, B.J., Menk, F.W., et al. Cusp-latitude Pc3 spectra: band-limited and power-law components, // Annales Geophysicae, 2002. - v. 20 - no. 10 - p. 1539.
25. Rodkin, M.V., Pisarenko, V.F. Extreme earthquake disasters: verification of the methods of parameterization of the character of distribution of the rare major events, // Advances in Geosciences, 2006. - v. 1 - p. 75.
26. Russell, C.T., Fleming, B.K. Magnetic pulsations as a probe of the interplanetary magnetic field: A test of the Borok $B$ Index, // Journal of Geophysical Research, 1976. - v. 81 - no. 34 - p. 5882.
27. Soloviev, A., Chulliat, A., Bogoutdinov, S., et al. Automated recognition of spikes in 1 Hz data recorded at the Easter Island magnetic observatory, // Earth Planets and Space, 2012. - v. 64 - no. 9 - p. 743.
28. Soloviev, A., Bogoutdinov, S., Gvishiani, A., et al. Mathematical tools for geomagnetic data monitoring and the INTERMAGNET Russian segment, // Data Science Journal, 2013. - v. 12 - p. 114.
29. Takahashi, K., McPherron, R.L., Terasawa, T. Dependence of the spectrum of Pc 3#x2013;4 pulsations on the interplanetary magnetic field, // JGR: Space Physics, 1984. - v. 89 - no. A5 - p. 114.
30. Uritsky, V., Smirnova, N., Troyan, V., Vallianatos, F. Dependence of the spectrum of Pc 3#x2013;4 pulsations on the interplanetary magnetic field, // Physics and Chemistry of the Earth, 2004. - v. 29 - p. 473.
31. Wolfe, A. Dependence of mid-latitude hydromagnetic energy spectra on solar wind speed and interplanetary magnetic field direction, // JGR: Space Physics, 1980. - v. 85 - no. A11 - p. 5977.
32. Vellante, M., Villante, U., De~Lauretis, M., Barchi, G. Solar cycle variation of the dominant frequencies of Pc3 geomagnetic pulsations at L = 1.6, // Geophysical Research Letters , 1995. - v. 23 - no. 12 - p. 1505.
33. Yagova, N.V. Spectral slope of high-latitude geomagnetic disturbances in the frequency range 1#x2013;5 mHz. Control parameters inside and outside the magnetosphere, // Geomagnetism and Aeronomy, 2015. - v. 55 - no. 1 - p. 32.
34. Yagova, N.V., Heilig, B., Pilipenko, V.A., et al. Nighttime Pc3 pulsations: MM100 and MAGDAS observations, // Earth, Planets and Space, 2017. - v. 69 - no. 61 - p. 1.
35. Yagova, N.V., Pilipenko, V.A., Fedorov, E.N., et al. Geomagnetically Induced Currents and Space Weather: Pi3 Pulsations and Extreme Values of Time Derivatives of the Geomagnetic Field's Horizontal Components, // Izvestiya, Physics of the Solid Earth, 2018. - v. 54 - no. 5 - p. 749.
36. Yumoto, K. External and Internal Sources of Low-Frequency MHD Waves in the Magnetosphere#x2013;A Review, // Journal of geomagnetism and geoelectricity, 1988. - v. 40 - no. 3 - p. 293.
37. Zelinsky, N.R., Kleimenova, N.G., Kozyreva, O.V., Agayan, S.M., Bogoutdinov, Sh.R., Soloviev, A.A. Algorithm for recognizing Pc3 geomagnetic pulsations in 1-s data from INTERMAGNET equatorial observatories, // Izvestiya, Physics of the Solid Earth, 2014. - v. 50 - no. 2 - p. 240.
