Индуктивный метод восстановления временных рядов геомагнитных данных

Today intensive development of systems and technologies for registration of the Earth’s magnetic field parameters causes an exponential increase of geomagnetic data quantity, mainly collected by the ground magnetic stations. Imperfection of applied equipment and enabled channels of information transfer leads to the presence of omissions in the registered data time series. Along with spatial anisotropy it creates a serious obstacle to the processing of geomagnetic data. Russian and foreign scientific organizations are used to recover missing geomagnetic data by the linear interpolation. The approach provides admissible results in conditions of a quiet magnetosphere, but significantly distorts time series when changing the surrounding magnetic environment. This fact causes a scientific and technical problem, which is concerned with the development of new approach to recovering geomagnetic data registered in unquiet magnetosphere with acceptable time series imputation quality metrics. The authors suggest the approach for time series recovering based on inductive method of machine learning. According to the approach each magnetic station operates its own knowledge base, which is formed during the registration of geomagnetic field and its variations parameters. The combination of the values of the series preceding and following the gap is supposed to be a characteristic description, which is used for searching the precedent in the magnetic station knowledge base. The result contains the required fragment of the time series, which replaces the missing values. The complexity of the information signal, caused by an unquiet magnetic environment, increases the accuracy of search by precedents. The greater the knowledge base of the magnetic station, the higher the effectiveness of the search. Analysis of the results obtained during gap recovering in geomagnetic data time series (registered in conditions of unquiet magnetosphere) demonstrated that the suggested inductive method of imputation allows increasing the accuracy of the missing values recovery by an average of 79.54% compared with the methods currently used. The approach will enhance the efficiency of geomagnetic data processing for solving applied problems.В настоящее время интенсивное развитие систем и технологий регистрации параметров магнитного поля Земли способствует экспоненциальному росту объемов геомагнитных данных, основным источником которых выступают постоянные магнитные станции. Несовершенство применяемой аппаратуры и задействованных каналов передачи информации обуславливает наличие пропусков во временных рядах зарегистрированных данных, что вместе с пространственной анизотропией создает серьезное препятствие для обработки геомагнитных данных при решении прикладных задач. Российские и зарубежные научные организации восстанавливают пропущенные геомагнитные данные методом линейной интерполяции, что обеспечивает приемлемые результаты в условиях спокойной магнитосферы, но значительно искажает временные ряды при изменении окружающей магнитной обстановки. В этой связи возникает актуальная научно-техническая задача разработки подхода к восстановлению геомагнитных данных в условиях возбужденной магнитосферы, обеспечивающего оптимальные метрики качества импутации временных рядов. Авторами предложен метод восстановления временных рядов, основанный на индуктивном методе обучения алгоритмов. Согласно предлагаемому подходу, каждая магнитная станция оперирует собственной базой знаний, формируемой в ходе регистрации параметров геомагнитного поля и его вариаций. Комбинация значений ряда, предшествующих и следующих за пропуском, является признаковым описанием, применяемым для поиска прецедента в базе знаний магнитной станции. Результат содержит искомый фрагмент временного ряда и заменяет пропущенные значения его уровней. Сложность характера информационного сигнала, обусловленная неспокойной магнитной обстановкой, повышает точность поиска по прецедентам, эффективность которого тем выше, чем большей базой знаний располагает магнитная станция. Проведенный анализ результатов восстановления пропусков временных рядов геомагнитных данных, зарегистрированных в условиях возбужденной магнитосферы, показал, что предложенный индуктивный метод импутации позволяет повысить точность восстановления пропущенных значений в среднем на 79.54 % по сравнению с используемыми в настоящее время методами, что позволит повысить эффективность обработки геомагнитных данных при решении прикладных задач

Method of analysis of geomagnetic data based on wavelet transform and threshold functions

The method is aimed at studying the dynamics of the magnetospheric current systems during magnetic storms. The method is based on algorithmic solutions for processing of geomagnetic field variations, for detection of local increases in geomagnetic disturbance intensity. Parameters of the algorithms allow us to evaluate the characteristics of small-scale local features emerging during geomagnetic activity slight increases and large-scale variations observed during magnetic storms. To evaluate the method, geomagnetic data from the stations located in the north-east of Russia and equatorial India were used. The method testing showed the possibility to apply it for the detection of pre-storm anomalous effects in geomagnetic data.This work was supported by the Grants of RSF No. 14-11-00194 and RFBR No.16-55-45007

Fractal Analysis and Chaos in Geosciences

The fractal analysis is becoming a very useful tool to process obtained data from chaotic systems in geosciences. It can be used to resolve many ambiguities in this domain. This book contains eight chapters showing the recent applications of the fractal/mutifractal analysis in geosciences. Two chapters are devoted to applications of the fractal analysis in climatology, two of them to data of cosmic and solar geomagnetic data from observatories. Four chapters of the book contain some applications of the (multi-) fractal analysis in exploration geophysics. I believe that the current book is an important source for researchers and students from universities

Multiscale variation model and activity level estimation algorithm of the Earth's magnetic field based on wavelet packets

We suggest a wavelet-based multiscale mathematical model of geomagnetic field variations. The model is particularly capable of reflecting the characteristic variation and local perturbations in the geomagnetic field during the periods of increased geomagnetic activity. Based on the model, we have designed numerical algorithms to identify the characteristic variation component as well as other components that represent different geomagnetic field activity. The substantial advantage of the designed algorithms is their fully automatic performance without any manual control. The algorithms are also suited for estimating and monitoring the activity level of the geomagnetic field at different magnetic observatories without any specific adjustment to their particular locations. The suggested approach has high temporal resolution reaching 1&thinsp;min. This allows us to study the dynamics and spatiotemporal distribution of geomagnetic perturbations using data from ground-based observatories. Moreover, the suggested approach is particularly capable of discovering weak perturbations in the geomagnetic field, likely linked to the nonstationary impact of the solar wind plasma on the magnetosphere. The algorithms have been validated using the experimental data collected at the IKIR FEB RAS observatory network.</p

Earth observations and global change decision making: A special bibliography, 1991

The first section of the bibliography contains 294 bibliographic citations and abstracts of relevant reports, articles, and documents announced in 'Scientific and Technical Aerospace Reports (STAR)' and 'International Aerospace Abstracts (IAA)'. These abstracts are categorized by the following major subject divisions: aeronautics, astronautics, chemistry and materials, engineering, geosciences, life sciences, mathematical and computer sciences, physics, social sciences, space sciences and general. Following the abstract section, seven indexes are provided for further assistance

Space weather instruments and measurement platforms

Avaruussää on Maapallon lähiavaruuden ilmiö. Sillä on useita ilmenemismuotoja, joista tunnetuin on revontulet. Avaruussää aiheuttaa haittaa kriittisille infrastruktuureille, kuten satelliiteille ja sähköverkoille. Tämän diplomityön tarkoituksena on tutkia nykyisiä avaruussääinstrumenttejä sekä mittausjärjestelmiä ja kartoittaa niiden toimintakyky sekä heikkouksia. Magnetometri-, ionosfääri, aurinkotuuli- ja Aurinkoinstrumentaatiolle ja järjestelmille suoritetaan kattava analyysi. Lopputulokset osoittavat että nykyiset instrumentit kykenevät mittaamaan kaikkia avaruussäähän liittyviä ilmiöitä. Magnetometrimittausten peitto revontuliovaalilla ei ole riittävä tarkkaan avaruussäätutkimukseen, sillä magneettikenttää ei kyetä mittaamaan merellä. Ionosfäärimittauksilla on samanlaisia ongelmia maantieteellisen peiton kanssa ja niistä on saatavilla lyhyempiä aikasarjoja. Aurinko- ja aurinkotuulimittaukset ovat keskittyneet pienelle määrälle satelliitteja jotka ovat kalliita ja hankalia korvata. Lopputuloksina suositellaan CubeSat-satelliittien kyytiin asennettavien magnetometrien testausta, vedenalaisten magnetometrien käyttöönottoa sekä parannuksia ionosfäärin ja magnetosfäärin mittauspeitossa. Kykyä suorittaa jatkuvia Aurinko- ja aurinkotuulimittauksia avaruuteen sijoitetuilla järjestelmillä pitäisi myös ylläpitää.Space weather is a phenomenon affecting near-Earth space. It manifests itself in numerous different ways, the best known being the Aurora. Space weather causes numerous problems to several critical infrastructures, such as power grids and satellites. This master’s thesis investigates current space weather instrumentation and systems to analyze their capabilities and possibly existing gaps in measurements. Analysis of magnetospheric, ionospheric, solar and solar wind instruments and instrument platforms is conducted. Our results show that currently existing instrumentation is able to measure essentially all space weather phenomena. Magnetometer coverage in auroral regions is not sufficient for detailed space weather analysis e.g. due to the lack of capability for measuring magnetic field at the sea. Ionospheric measurements have similar problems with coverage, but they also have rather short time series. Solar and solar wind observations are concentrated on a small number of orbital observatories that are difficult to replace and expensive. In conclusion, testing of CubeSat mounted fluxgate magnetometers, adoption of underwater magnetometers and improvements in coverage of ionospheric and magnetospheric measurements are suggested. Maintenance of the ability to conduct in situ measurements of solar wind and and solar observations are recommended

NMDB@Home 2020: Proceedings of the 1st virtual symposium on cosmic ray studies with neutron detectors

With the 'Proceedings of the 1st virtual symposium on cosmic ray studies with neutron detectors' launches the new open access series 'Cosmic ray studies with neutron detectors'. The volume comprises the papers presented at the online meeting held in July 2020. The contributions show that neutron detectors on the ground provide significant results for studying the interaction of galactic cosmic rays with magnetic fields in the heliosphere, for accelerating energetic particles, and for a growing number of applications, including geophysics and space weather. The easily accessible databases around the project 'Real-Time database for high resolution Neutron Monitor measurements' (NMDB) make the original data readily available to a large user community.Die 'Proceedings of the 1st virtual symposium on cosmic ray studies with neutron detectors' eröffenen die neue Open-Access-Reihe 'Cosmic ray studies with neutron detectors'. Der Band umfasst die bei dem im Juli 2020 veranstalteten Online-Treffen präsentierten wissenschaftlichen Arbeiten. Die Beiträge zeigen, dass Neutronendetektoren am Boden bedeutende Ergebnisse liefern: zur Erforschung der Wechselwirkung der galaktischen kosmischen Strahlung mit Magnetfeldern in der Heliosphäre, zur Beschleunigung von energetischen Teilchen sowie für eine wachsenden Anzahl von Anwendungen, unter anderem in Bezug auf die Geophysik und das Weltraumwetter. Die leicht zugänglichen Datenbanken rund um das Projekt 'Real-Time database for high resolution Neutron Monitor measurements' (NMDB) machen die Originaldaten für eine große Nutzergemeinschaft leicht zugänglich