Geomagnetic Parameters Research Articles

Issue Information

Cover. In Zanetti et al. [DOI: 10.1002/2014SW001108]: The example of Van Allen Probes space weather display shown here was especially configured to include the trajectory of NASA's JUNO spacecraft as it performed a gravity assist maneuver on 9 October 2013. Shown on the right are the Van Allen Probes spacecraft orbits, viewing Van Allen Probes/RBSP‐A and ‐B orbits from north zenith in GSE coordinates, the sun is toward the right. On the left are the ECT/REPT energetic particle data from RBSP‐A received and displayed in near real‐time, with L‐shell intensity vs. time. Approximately one month of data are shown. Also shown is the geomagnetic parameter DsT indicating geomagnetic activity. The middle electron intensity channel shown to the left is also used to paint the spacecraft orbit with that channel intensity. The real‐time Van Allen Probes data access – Science Gateway – can be found at http://rbspgway.jhuapl.edu. See pp. 577–581.

Frequency of Solar Spotless Days and Flare Index as Indices of Solar Cycle Activity

There was a research on the prolongation of solar cycle 23 by the solar cyclic variation of solar, interplanetary geomagnetic parameters by Oh & Kim (2013). They also suggested that the sunspot number cannot typically explain the variation of total solar irradiance any more. Instead of the sunspot number, a new index is introduced to explain the degree of solar activity. We have analyzed the frequency of sunspot appearance, the length of solar cycle, and the rise time to a solar maximum as the characteristics of solar cycle. Then, we have examined the predictability of solar activity by the characteristics of preceding solar cycle. We have also investigated the hemispheric variation of flare index for the periods that the leading sunspot has the same magnetic polarity. As a result, it was found that there was a good correlation between the length of preceding solar cycle and spotless days. When the length of preceding solar cycle gets longer, the spotless days increase. It is also shown that the shorter rise time to a solar maximum is highly correlated with the increase of sunspots at a solar maximum. Therefore, the appearance frequency of spotless days and the length of solar cycle are more significant than the general sunspot number as an index of declining solar activity. Additionally, the activity of flares leads in the northern hemisphere and is stronger in the hemisphere with leading sunspots in positive polarity than in the hemisphere with leading sunspots in negative polarity. This result suggests that it is necessary to analyze the magnetic polarity’s effect on the flares and to interpret the period from the solar maximum to solar maximum as the definition of solar cycle.

Prominent short-, mid-, and long-term periodicities in solar and geomagnetic activity: Wavelet analysis

Study of periodicities in solar and geomagnetic parameters has been useful in relating solar variability to variations in other phenomena in order to search for the solar cause of, and effects in, the variability observed in near earth space environment. Implementing wavelet analysis on daily, monthly and yearly time resolution data of sunspot number and geomagnetic aa-index, we observed periodicities of 27.8-, 157-, 370-days, and 2.2-, 5.5-, 11-, 22.7-, 38.6-years in the sunspot spot number and 13.8-, 26.6-, 185-days, and 5.3-, 11-, 30-, 46-years in the geomagnetic aa-index. We discuss these periodicities, relation between solar and geomagnetic periodicities and their implications for near-earth space environmental effects.

Natural and man-made influences on suicides in northwestern Russia

Our main aim was to identify the impacts of natural (solar activity, geomagnetic disturbances) and man-made factors on suicides in northwestern Russia. Data on a total of 908 suicides in the town of Kirovsk (Murmansk oblast) were analyzed for the period from 1948 to 2010. The rates of suicides were analyzed with respect to seasons of the year. We have identified three maxima in the seasonal distribution of the number of suicides [March–May (P 150 nT) magnetic storms. Multi-taper method-spectrum analysis revealed periodicities (~9–10 and ~25 years) which may be related to the main cycles of solar activity. The periods of ~3.1–3.5 and ~2–2.3 years are probably the third and the fifth harmonics of 11-year solar cycle, respectively. These periods are correlating with similar periodic variations in geomagnetic aa-indexes and meteorological parameters. It was determined the statistically significant (r = 0.8; P = 0.005) relationship between suicide and Cu emissions from Cu–Ni smelters of Russian North for the period 1997–2009.

Trend of major earthquakes during the period 1900–2011 and its association with some solar and geomagnetic parameters

The paper presents long term trend of major earthquake (magnitude ≥6 Richter scale) occurrence throughout world. Analysis shows that occurrence trend decreases during the period 1900–1962, afterwards the trend increases. Solar coronal index, geomagnetic disturbance indices (Kp, Ap index) follow the opposite trend during the above mentioned period. Possible explanation is presented.

Variation of Solar, Interplanetary and Geomagnetic Parameters during Solar Cycles 21-24

The length of solar cycle 23 has been prolonged up to about 13 years. Many studies have speculated that the solar cycle 23/24 minimum will indicate the onset of a grand minimum of solar activity, such as the Maunder Minimum. We check the trends of solar (sunspot number, solar magnetic fields, total solar irradiance, solar radio flux, and frequency of solar X-ray flare), interplanetary (interplanetary magnetic field, solar wind and galactic cosmic ray intensity), and geomagnetic (Ap index) parameters (SIG parameters) during solar cycles 21-24. Most SIG parameters during the period of the solar cycle 23/24 minimum have remarkably low values. Since the 1970s, the space environment has been monitored by ground observatories and satellites. Such prevalently low values of SIG parameters have never been seen. We suggest that these unprecedented conditions of SIG parameters originate from the weakened solar magnetic fields. Meanwhile, the deep 23/24 solar cycle minimum might be the portent of a grand minimum in which the global mean temperature of the lower atmosphere is as low as in the period of Dalton or Maunder minimum.

Magnetometric Measurements at Mt. Aragats

Magnetometric station LEMI-018, and LEMI-417 commissioned by Lviv center of Space Research Institute of Ukrainian Academy of Science, have been installed on the slope of mountain Aragats (Armenia) at heights 2000 and 3200m above sea level. Operation of magnetometric station started on July 2009 and 2011 accordingly. LEMI-417 is measuring also components of the electric field. One second time series of the 3-dimensional measurements of the geomagnetic field enter the data base of the Aragats Space Environmental Center (ASEC) and will highly improve research of correlations of the geomagnetic parameters, and changes of the fluxes of secondary cosmic rays by ASEC monitors and interplanetary magnetic field (IMF) measured by facilities on board space station located 1.5 mln km from Earth will assist to understand Solar influence on the Earth environments. Measurements of geomagnetic field at Nor Amberd (2000m) and Aragats (3200m) research stations of A.Alikhanyan national lab will support forewarning of the upcoming major geomagnetic storms. We present the detection of the first geomagnetic storms of the 24 solar activity cycle detected by new installed magnetometric stations.

Geomagnetic response to solar and interplanetary disturbances

The space weather discipline involves different physical scenarios, which are characterised by very different physical conditions, ranging from the Sun to the terrestrial magnetosphere and ionosphere. Thanks to the great modelling effort made during the last years, a few Sun-to-ionosphere/thermosphere physics-based numerical codes have been developed. However, the success of the prediction is still far from achieving the desirable results and much more progress is needed. Some aspects involved in this progress concern both the technical progress (developing and validating tools to forecast, selecting the optimal parameters as inputs for the tools, improving accuracy in prediction with short lead time, etc.) and the scientific development, i.e., deeper understanding of the energy transfer process from the solar wind to the coupled magnetosphere-ionosphere-thermosphere system. The purpose of this paper is to collect the most relevant results related to these topics obtained during the COST Action ES0803. In an end-to-end forecasting scheme that uses an artificial neural network, we show that the forecasting results improve when gathering certain parameters, such as X-ray solar flares, Type II and/or Type IV radio emission and solar energetic particles enhancements as inputs for the algorithm. Regarding the solar wind-magnetosphere-ionosphere interaction topic, the geomagnetic responses at high and low latitudes are considered separately. At low latitudes, we present new insights into temporal evolution of the ring current, as seen by Burton’s equation, in both main and recovery phases of the storm. At high latitudes, the PCC index appears as an achievement in modelling the coupling between the upper atmosphere and the solar wind, with a great potential for forecasting purposes. We also address the important role of small-scale field-aligned currents in Joule heating of the ionosphere even under non-disturbed conditions. Our scientific results in the framework of the COST Action ES0803 cover the topics from the short-term solar-activity evolution, i.e., space weather, to the long-term evolution of relevant solar/heliospheric/magnetospheric parameters, i.e., space climate. On the timescales of the Hale and Gleissberg cycles (22- and 88-year cycle respectively) we can highlight that the trend of solar, heliospheric and geomagnetic parameters shows the solar origin of the widely discussed increase in geomagnetic activity in the last century.

Where on earth can animals use a geomagnetic bi‐coordinate map for navigation?

Many animal taxa have been shown to possess the ability of true navigation. In this study we investigated the possibilities for geomagnetic bi‐coordinate map navigation in different regions of the earth by analysing angular differences between isolines of geomagnetic total intensity and inclination. In ‘no‐grid’ zones where isolines were running almost parallel, efficient geomagnetic bi‐coordinate navigation would probably not be feasible. These zones formed four distinct areas with a north‐south extension in the northern hemisphere, whereas the pattern in the southern hemisphere was more diffuse. On each side of these zones there was often a mirror effect where identical combinations of the geomagnetic parameters appeared. This may potentially cause problems for species migrating long distances east‐west across longitudes, since they may pass areas with identical geomagnetic coordinates. Migration routes assumed for four populations of migratory passerine birds were used to illustrate the possibilities of geomagnetic bi‐coordinate map navigation along different routes. We conclude that it is unlikely that animal navigation is universally based on a geomagnetic bi‐coordinate map mechanism only, and we predict that the relative importance of geomagnetic coordinate information differs between animals, areas and routes, depending on the different conditions for bi‐coordinate geomagnetic navigation in different regions of the earth.

Comments on “Interplanetary and geomagnetic parameters during January 16–26, 2005” by R.P. Kane

We write this note of clarification to show that Kane (2012) has incorrectly interpreted the interplanetary magnetic field during the event by using low time-resolution data, and has thus misinterpreted the concluding comments of Du et al. (2008). Our recent paper (Du et al., 2011b) has shown that the solar wind energy input during northward IMF events is very low. Thus the interpretation of the Du et al. (2008) article given by the authors stand as was stated.

Monitoring the volcanic unrest of El Hierro (Canary Islands) before the onset of the 2011–2012 submarine eruption

On 10 October 2011, a submarine volcanic eruption started 2 km south from El Hierro Island (Spain). Since July 2011 a dense multiparametric monitoring network was deployed all over the island by Instituto Geográfico Nacional (IGN). By the time the eruption started, almost 10000 earthquakes had been located and the deformation analyses showed a maximum deformation of more than 5 cm. Earthquake migration from the north to the south of the island and acceleration of seismicity are in good correlation with changes in the deformation pattern as well as with some anomalies in geochemical and geomagnetic parameters. An earthquake of local magnitude 4.3 at 12 km depth (8 October 2011) and shallower seismicity a day after, preceded the onset of the eruption. This is the first time that a volcanic eruption is fully monitored in the Canary Islands. Data recorded during this unrest episode at El Hierro will contribute to understand reawakening of volcanic activity in this region and others of similar characteristics.

Interplanetary and geomagnetic parameters during January 16–26, 2005

The interplanetary Bz(min) and geomagnetic Dst(min) are well related. There is no large negative Bz without causing large negative Dst. Similarly, large negative Dst is not expected to occur without a large negative Bz; but recently, Du et al. (2008) reported that the Dst storm of Jan. 21–22, 2005 was anomalous because the Dst storm main phase developed during northward interplanetary magnetic field (positive Bz). Here, we examined this event (storm 3) and compared it with earlier events of Jan. 16–20, 2005 (storms 1 and 2, in quick succession). It was noticed that storms 1 and 2 had large negative Dst deviations (−121nT and −93nT, separated by 26 hours) but the Bz fluctuated between +21nT and −17nT. For storm 3 where negative Dst deviations were large (−105nT), the Bz was not completely positive (northward) as mentioned by Du et al. (2008) but had negative values (−7nT) for an hour, followed by positive values (13nT). Thus, the need of a negative Bz (albeit small) was satisfied.

Magnetic declination measurements over European Russia and Siberia in the 18th century

The paper presents the history of measurements of the geomagnetic field parameters over the territory of Russia in the 18th century derived from archival and literature sources. Topographical mapping of the European territory and neighboring seas of the Russian Empire from the late 17th to the mid 18th century during which magnetic measurements were made was of great importance for determining magnetic declination. The magnetic declination in Siberia and its neighboring seas was measured for the first time during the first expedition of V. Bering in 1728 and then during his second expedition (the Great Northern Expedition) in 1733–1742. Magnetic measurements were carried out along the northern coast of Siberia and in the Bering Sea. The academic group of the expedition performed magnetic declination measurements over southern regions of Siberia (Krasnoyarsk, Irkutsk, Nerchinsk, Yakutsk, etc.) in 1735 and 1736. During the second half of the 18th century, Russian expeditions determined geographical coordinates of the cities of European Russia and carried out magnetic declination measurements for them. During these expeditions Inokhodtsev paid attention to the anomalous magnetic declination in the Kursk region. In his opinion, the anomaly could have been caused by the presence of iron ore.

Outlier Identification and Correction Online for the Ocean Geomagnetic Parameter Measurement

The outlier identification and correction of the geomagnetic parameter measurement is an important influencing factor for the probability and precision of the matching algorithms. The ream-time measurements of the geomagnetic field parameter can be considered as the first-order non-stationary random process, the real-time measurement value can be predicted by using the multi-level recursive method, the outlier identification can be done by the Dixon criterion, and the correction can be made by using the median filter and the one step prediction value. The inspection is carried out by using the emulation data and actual data, the results show that not only the isolated type but also the spot-type outlier value can be detected well and the signal reconstruction error is less than 5%.

Solar wind high-speed streams and related geomagnetic activity in the declining phase of solar cycle 23

Context. Coronal holes (CHs) are the source of high-speed streams (HSSs) in the solar wind, whose interaction with the slow solar wind creates corotating interaction regions (CIRs) in the heliosphere. Aims. We investigate the magnetospheric activity caused by CIR/HSS structures, focusing on the declining phase of the solar cycle 23 (years 2005 and 2006), when the occurrence rate of coronal mass ejections (CMEs) was low. We aim to (i) perform a systematic analysis of the relationship between the CH characteristics, basic parameters of HSS/CIRs, and the geomagnetic indices Dst, Ap and AE; (ii) study how the magnetospheric/ionospheric current systems behave when influenced by HSS/CIR; (iii) investigate if and how the evolution of the background solar wind from 2005 to 2006 affected the correlations between CH, CIR, and geomagnetic parameters. Methods. The cross-correlation analysis was applied to the fractional CH area (CH) measured in the central meridian distance interval ±10 ◦ , the solar wind velocity (V), the interplanetary magnetic field (B), and the geomagnetic indices Dst, Ap ,a ndAE. Results. The performed analysis shows that Ap and AE are better correlated with CH and solar wind parameters than Dst ,a nd quantitatively demonstrates that the combination of solar wind parameters BV 2 and BV plays the central role in the process of energy transfer from the solar wind to the magnetosphere. Conclusions. We provide reliable relationships between CH properties, HSS/CIR parameters, and geomagnetic indices, which can be used in forecasting the geomagnetic activity in periods of low CME activity.

An improved method for geological boundary detection of potential field anomalies

Potential field methods such as gravity and magnetic methods are among the most applied geophysical methods in mineral exploration. A high-resolution technique is developed to image geologic boundaries such as contacts and faults. Potential field derivatives are the basis of many interpretation techniques. In boundary detection, the analytic signal quantity is defined by combining the values of horizontal and vertical derivatives. The outlines of the geologic boundaries can be determined by tracing the maximum amplitudes of analytic signal. However, due to superposition effects, in some cases that a variety of sources are adjacent, the detected boundaries are blurred. To overcome this problem, this study used enhanced analytic signal composed of the nth- order vertical derivative of analytic signal. The locations of its maximum amplitudes are independent of magnetization direction and geomagnetic parameters. This technique is particularly suitable when interference effects are considerable and when remanent magnetization is not negligible. In this paper this technique has been applied to gravity data of southwest England. Using this method, five granites outcrops and their separating faults are enhanced accurately.

Solar Rotational Periodicities and the Semiannual Variation in the Solar Wind, Radiation Belt, and Aurora

The behavior of a number of solar wind, radiation belt, auroral and geomagnetic parameters is examined during the recent extended solar minimum and previous solar cycles, covering the period from January 1972 to July 2010. This period includes most of the solar minimum between Cycles 23 and 24, which was more extended than recent solar minima, with historically low values of most of these parameters in 2009. Solar rotational periodicities from 5 to 27 days were found from daily averages over 81 days for the parameters. There were very strong 9-day periodicities in many variables in 2005 – 2008, triggered by recurring corotating high-speed streams (HSS). All rotational amplitudes were relatively large in the descending and early minimum phases of the solar cycle, when HSS are the predominant solar wind structures. There were minima in the amplitudes of all solar rotational periodicities near the end of each solar minimum, as well as at the start of the reversal of the solar magnetic field polarity at solar maximum (∼ 1980, ∼ 1990, and ∼ 2001) when the occurrence frequency of HSS is relatively low. Semiannual equinoctial periodicities, which were relatively strong in the 1995 – 1997 solar minimum, were found to be primarily the result of the changing amplitudes of the 13.5- and 27-day periodicities, where 13.5-day amplitudes were better correlated with heliospheric daily observations and 27-day amplitudes correlated better with Earth-based daily observations. The equinoctial rotational amplitudes of the Earth-based parameters were probably enhanced by a combination of the Russell-McPherron effect and a reduction in the solar wind-magnetosphere coupling efficiency during solstices. The rotational amplitudes were cross-correlated with each other, where the 27-day amplitudes showed some of the weakest cross-correlations. The rotational amplitudes of the > 2 MeV radiation belt electron number fluxes were progressively weaker from 27- to 5-day periods, showing that processes in the magnetosphere act as a low-pass filter between the solar wind and the radiation belt. The Ap/Kp magnetic currents observed at subauroral latitudes are sensitive to proton auroral precipitation, especially for 9-day and shorter periods, while the Ap/Kp currents are governed by electron auroral precipitation for 13.5- and 27-day periodicities.

Rock-magnetic and archeomagnetic survey from some classical settlements at Chapultepec archeological site (western Mesoamerica)

Many archaeological artifacts contain magnetic minerals that may record the direction and strength of the Earth’s magnetic field. The geomagnetic field parameters (declination, inclination and intensity) change through time and then may be used as a dating tool. Over the last three decades, the archeomagnetic method was successfully applied in Europe. Still, no systematic studies are devoted to the American sites. We report here, a detailed rock-magnetic and archeomagnetic investigation of some pre-Columbian settlements at Chapultepec archeological site (western Mesoamerica). Continuous low-field susceptibility vs. temperature curves performed in air point to Ti-poor titanomagnetites as remanence carriers. Hysteresis ratios fall essentially in the pseudo-single-domain region. The twelve oriented samples taken from the furnace located in the habitation area were demagnetized applying pick alternative fields. In most cases, a stable uni-vectorial remanent magnetization was found yielding a reasonably well defined mean characteristic direction: inclination I = 32.8°, declination D = 353.4°, and parameters of Fisherian statistics α95 = 10.4° and k = 14. Still poorly defined directional master curves for Mesoamerica, together with relatively dispersed mean directions obtained in this study, make dating targets difficult. Archaeomagnetic dating was carried out on the basis of Bayessian statistics. This established a most probable time interval from 512 to 634 A.D. with an average of 573 ± 61 A.D.

Space weather in the thermospheric–ionospheric domain over the Brazilian region: Climatology of ionospheric plasma bubbles in the subequatorial and low-latitude region

The climatology of ionospheric plasma bubbles is studied here by means of a comparison of the frequency of occurrence of the spread-F/plasma bubble events over the South American region using the images from two OI 630 nm imager systems located at the subequatorial station São João do Cariri—CA (7.4 S, 36.5 W, 20 S dip) and the low-latitude station Cachoeira Paulista—CP (22.5 S, 45 W, 33 S dip) in Brazil during the years of 2004 and 2005. The results are discussed in the light of current theory and geomagnetic parameters of the two observation stations.

Ionospheric perturbations of electron density before the Wenchuan Earthquake

Based on electron density data recorded by the Detection of Electro-Magnetic Emissions Transmitted from Earthquake Regions (DEMETER) satellite of France, the phenomena of disturbed electron density in the ionosphere before the Wenchuan Earthquake of magnitude 8.0 on 12 May 2008, were analysed. The results showed that the anomalies concentrated 3 days prior to the earthquake, especially the variation on 9 May, when the electron density reduced above the northeast epicentral area, and the peak values moved to the equator. Compared with the variations in the geomagnetic indexes and other parameters related to solar activity, the geomagnetic condition and solar activity were all quiet from 7 to 12 May, so the variation on 9 May might be related to this strong earthquake. In addition, the geomagnetic field observed at the surface was analysed, and the Z component data at stations near the epicentral area showed apparent aberrations of daily variation compared with those at stations in eastern China. All these phenomena illustrate that obvious perturbations in the ionosphere and at the surface might be related to the preparation process of the Wenchuan Earthquake.