ON THE FIRST RESULTS OF MEASUREMENTS OF GEOMAGNETIC SHORT-PERIOD FIELD VARIATIONS IN THE ODESA MAGNETIC ANOMALY ZONE WITH A SECOND-LONG RESOLUTION

Abstract

Purpose: Since November 2017 till April 2018, the variation of geomagnetic field component was monitored at the Astronomical Observatory of the I. I. Mechnikov Odesa National University with the aim of investigating the mid-latitude geomagnetic pulsations in the central region of the Odesa magnetic anomaly. Design/methodology/approach: The measurements were made by using the precision LEMI-008 flux-gate magnetometer with a sample rate of 1 Hz. The data obtained were processed daily by using the method of continuous wavelet analysis, as well as band-pass filtering based on it, in order to separate individual frequency bands containing quasi-harmonic pulsations. Findings: The results of observations of the northern Bx - component of the geomagnetic field induction vector during the geomagnetic disturbances, storms and under quiet conditions were analyzed by using the method of continuous wavelet analysis. The presence of predominant quasiperiods of fast pulsations of ≈ 9÷30 min observed during the day with decreasing periods and their duration of appearance in the data during magnetic storms is noted. Also, during the storms, there is usually an increase in the proportion of irregular and short-term pulsations in observational data. Due to the presence of technogenic urban noise in records, the results are compared with the reference monitoring of geomagnetic variations at the “Odesa” geomagnetic observatory located in the Stepanivka village, Odesa region. It is shown that technogenic city noise at the magnetometer location is most evident on sections of wavelet spectra from the periods of 5 minutes or less. Conclusions: The data of a long-term monitoring of the geomagnetic field variation component in the most interesting central part of the Odesa magnetic anomaly were obtained, where earlier such studies were never carried out. An idea is given of the main spectra of geomagnetic pulsations and their comparison in magnetically quiet days and days of magnetic storms.

Keywords

• geomagnetic variations
• solar-terrestrial connections
• magnetic anomaly
• magnetometer
• geomagnetic pulsations