The response of geomagnetic spectral composition to solar wind during storm time

In this paper 16 geomagnetic storms in 1968–1978 recorded at 8 magnetic observatories located from polar to equatorial regions in the λ= 120°E longitudinal zone and its vicinity have been analysed. The horizontal component H traces of 27 h intervals have been sampled once every 1.5 min. The time sequences of the data thus obtained have been processed by the method of digital filtering and maximum entropy spectral analysis (MESA).The results of the analysis are compared with the associated solar wind parameters. It confirms that the geomagnetic disturbances are controlled by the solar wind in several ways, i.e. geomagnetic disturbances respond differently to various solar wind parameters or to the different ranges of them. The north-south component of the interplanetary magnetic field (IMF) B_z., the IMF latitude θ and the solar wind velocity V play the most important part in inducing geomagnetic storms.     

Solar origin of geomagnetic storms and predictions

Changes of the large-scale solar magnetic fields are described and related to the occurrence of solar coronal phenomena which are associated with geomagnetic storms. Only for the very largest geomagnetic storms is there agreement on the coronal origin. However, when and where coronal mass ejections occur are still very difficult questions to answer. Artificial neural networks have been used to forecast geomagnetic storms either from daily solar input data or from hourly solar wind data. With solar data as input, predictions one-three days or even a month in advance are possible, while using solar wind data as input predictions about an hour in advance are possible. The latter predictions have been very successful. Finally, the effects of geomagnetic storms on power and satellite systems are reviewed.     

Tropical nightglow observations and predictions from ionospheric models

To study the tropical nightglow emissions in the vicinity of the Brazilian magnetic anomaly, two balloons were flown in February 1973 and 1977 carrying photometers. The behaviour in the tropical nightglow of the 630 and 557.7 nm lines is described and compared with predictions based on recent ionospheric models. Possible effects of the magnetic activity on the F2-layer in the tropics are suggested which are not accounted for by the ionospheric models.     

The national security implications of solar geoengineering: an Australian perspective

ABSTRACT

Given current emissions trends an increase in global temperatures in excess of 2°C is highly likely in the coming century. In this context, it seems increasingly probable that states may consider solar geoengineering as a stop-gap climate response. Solar geoengineering refers to measures that aim to alleviate some measure of global warming by intentionally increasing the amount of the sun’s energy that is reflected into space. Currently the two most discussed solar geoengineering techniques involve either marine cloud brightening or dispersing aerosols in the stratosphere. These techniques could be relatively inexpensive, are within the technological capacities (after a brief period of development) of technologically-advanced countries, and could have an almost immediate impact on temperatures. Yet, while solar geoengineering might potentially be utilised to manage some climate-linked security threats, it itself would create new security challenges. Consequently, this paper explores potential international security implications for Australia if a regional state, or group of states, initiates a solar geoengineering program. We conclude that since solar geoengineering is unlikely to become a first-order international issue, disputation over solar geoengineering will likely reflect, or act as a proxy for, wider patterns of state interaction. However, scenarios in which China and the United States take different positions, or in which there are divisions among regional powers, such as Indonesia, Malaysia, India and Singapore would pose the greatest threat to Australia’s national security.     

The trouble with thermospheric vertical winds: geomagnetic,seasonal and solar cycle dependence at high latitudes

The vertical wind component is frequently used to determine the zero-velocity baseline for measurements of thermospheric winds by Fabry-Perot and other interferometers. For many of the upper atmospheric emission lines from which Doppler shifts are determined, for example for the OI 630 nm emission, available laboratory sources are not convenient for long-term use at remote automatic observatories. Therefore, the assumption that the long-term average vertical wind is zero is frequently used to create a baseline from which the Doppler shifts corresponding with the line-of-sight wind from other observing directions can then be calculated. A data base consisting of 1242 nights of thermospheric wind measurements from Kiruna (68°N, 20°E), a high-latitude site, has been analysed. There are many interesting short-term fluctuations of the vertical wind which will be discussed in future papers. However, the mean vertical wind at Kiruna also has a systematic variation dependent on geomagnetic activity, season and solar cycle. This means that the assumption that the average value of the vertical wind is zero over the observing period cannot be used in isolation to determine the instrument reference or baseline. Despite this note of caution, even within the auroral oval, the assumption of a zero mean vertical wind can be used to derive a baseline which is probably valid within 5 ms⁻¹ during periods of quiet geomagnetic activity (K_p < 2), near winter solstice. During other seasons, and during periods of elevated geomagnetic activity, a systematic error in excess of 10 ms⁻¹ may occur.     

With the face to the future: The kibbutz in recent literary works

The kibbutz, which was considered one of the greatest successes of the socialist dream, failed to survive history, which replaced socialism with both capitalism and globalization. Numerous texts, literary, documentary, and scholarly, have tried to comprehend the social developments that took place in the kibbutz during the period of its demise, especially over the 1980s and the 1990s. This article focuses on two works – Habayta (Home, Assaf Inbari, 2009) and Bein haverim (Between friends, Amos Oz, 2012) – both of which refrain from solely addressing the rift that the kibbutz underwent, but rather attempt to see in the moment of the kibbutz's disintegration a stage in a historical process that will ultimately enable creation of new values on the ruins of the old ones. Both works triggered powerful response from literary critics and from the general public, and contributed to shaping a new perspective on the history of the kibbutz.     

Influence of solar flares and disturbances of the interplanetary medium on the atmospheric circulation

The atmospheric circulation response to solar flares and geomagnetic disturbances is studied. It is shown that solar flares cause an increase of the zonal circulation intensity in the latitudinal belt ϑ = 45–65°, while geomagnetic disturbances are associated with a decrease of the circulation intensity.The energy necessary to produce the observed atmospheric circulation changes is estimated. The variation of the atmospheric transparency is suggested to be a possible source of that energy.     

Lunar and solar daily variations of the geomagnetic field at Italian stations

Mean hourly values of magnetic declination D, horizontal intensity H and vertical intensity Z observed at Italian stations have been analyzed to determine solar and luni-solar diurnal components, together with the corresponding terms O₁ and N₂ of the lunar tidal potential.The results, showing the variations of the first four harmonic components with season, degree of magnetic activity and annual sunspot number, are tabulated and discussed. Differences between the dependence of S and L on season and sunspot number are considered and tentative explanations offered. The oceanic tidal effect has been determined and it is apparent that this is more likely to show the influence of the Atlantic Ocean rather than the Mediterranean Sea.     

A survey of simultaneous observations of the high-latitude ionosphere and interplanetary magnetic field with EISCAT and AMPTE-UKS

This paper surveys the results of simultaneous observations by the EISCAT incoherent scatter radar and the AMPTE-UKS satellite, made during three periods in September and October 1984, when AMPTE-UKS was in the solar wind on the dayside of the Earth and the UK-POLAR EISCAT experiment was measuring ionospheric parameters at invariant latitudes 70.8–75.0°. A total of 42 h of EISCAT convection velocity data, with 2.5 min resolution, were obtained, together with 28 h of simultaneous 5 s resolution AMPTE-UKS observations of the solar wind and interplanetary magnetic field (IMF). The general features of the AMPTE-UKS data are described in Section 2 and those of the EISCAT data are described in Sections 3 and 4. The main subjects discussed are the form of the plasma convection patterns and their dependence on all three components of the IMF (Section 5), the ionospheric response to abrupt changes in the IMF (Section 6), in particular a sharp ‘southward turning’ of the IMF on 27 October 1984, and a crossing of an IMF sector boundary. Section 7 describes ‘short lived rapid flow burst’, which are believed to be related to flux transfer events at the magnetopause.     

Simulation of ionospheric currents and geomagnetic field variations of Sq for different solar activity

Variations of ionospheric Sq electric currents and fields caused by changes in electric conductivity due to changes in solar activity are studied using the International Reference Ionosphere (IRI) model. Calculations are made for R (sunspot number) = 35 and 200 on the assumption of constant (1, −2)mode tidal winds. It is shown that electric fields grow when solar activity is high, because the ratio of the conductivity in the F-region to that in the E-region increases. Currents in the F-region become stronger than those in the E-region, and nocturnal currents are not negligible when solar activity becomes high. F-region currents also play an important role in the westward currents on the high latitude side of the current vortex. The calculated geomagneticH component at the equator has a depression around 1600 LT for R = 35, while it decreases smoothly from 1100 LT to 1900 LT for R = 200. This difference is consistent with the observed geomagnetic field variation. The ratio of total Sq currents obtained by our simulation is about 3.5, which is a little larger than is found in the observed results.     

More than a storm in a teacup: the defence and security implications of Scottish independence

In September 2014 the people of Scotland will vote on whether to become an independent nation, with the defence and security of Scotland proving to be one of the more vociferous areas of debate. This article argues that defence and security implications of this referendum are far more fundamental than either the ‘yes’ or ‘no’ campaigns have admitted. It makes four points. First, it suggests that the Scottish government's plans for defence and security in NATO and the EU are at odds with its proposed armed forces and that Scotland may well find itself having to make far greater commitments to defence to assure its allies. Second, it argues that a vote for independence will represent a game‐changing event for the remainder of the United Kingdom's defence and security, which will have significant consequences for the United Kingdom's partners and allies in NATO, the European Union and elsewhere. Third, the article contends that even a vote against independence will have a long‐term impact, in that the ‘West Lothian question’ and Scottish support for nuclear disarmament influence the 2015 Strategic Defence and Security Review. Finally, the article highlights how this issue has revealed weaknesses in the think‐tank and academic communities, particularly in Scotland. The independence vote does, therefore, represent ‘more than a storm in a tea cup’ and thus there needs to be far greater engagement with these issues within the United Kingdom and elsewhere.     

Microscope observations and DNA analysis of wine residues from Roman amphorae found in Ukraine and from bottles of recent Tuscan wines

Morphological analysis by light and electron microscopy was conducted on wine residues from second century Roman amphorae found in Myrmekion (Ukraine). The results of the archaeological samples were compared with residues formed in bottles of wine from Tuscan vineyards, corked between 1969 and 1977 without filtration and enzyme or biochemical processing. Staining and histochemical observation of the archaeological and recent residues detected nucleic acids. Molecular analysis was also performed using nuclear microsatellite SSRs markers having high polymorphism to study genetic relationships. Genotype profiles of archaeological and recent residues were compared with contemporary cultivars in a data bank. Low homology of genotype profiles of all residues, and oral evidence, confirmed the presence of autochthonous varieties in recent wines and enabled indirect assessment of varieties detected in the archaeological material. The results confirmed that the archaeological material could be related to Sangiovese and indicated Roman wine trade as far afield as Ukraine, whereas the recent residues provided evidence of disappearing native Tuscany cultivars like Gorgottesco, Mammolo, Verdello, Rossone and Tenerone, used for table wines until the late seventies.     

Raised relief on nephrite jade artifacts: observations,explanations and implications

Mineralogical analyses of nephrite jade artifacts have been used to identify likely causes of alterations in which some specimens exhibit raised relief above the original polished surfaces. In all of the specimens examined, the raised areas consist of either large diopside ± large tremolite crystals, or, in a few cases, only fibrous tremolite, within a non-raised matrix of nephrite (fibrous tremolite). Apparent relief may be cause by a number of different effects, either mechanical (abrasive), chemical (e.g., dissolution), or a combination (mineralogical alteration leading to formation of relief). The most enigmatic examples occur where the relief formed after the object was polished and can not be easily attributed to chemical dissolution or mechanical abrasion. One possible explanation for these is that minor amounts of secondary growth of hydrous minerals, such as clays along grain boundaries, produced a volume increase which caused the crystals to rise. Carbon-14 analysis on one vessel that displays raised relief has produced an age of 3010 ± 30 years before present for organic material that coated the alteration.     

The middle atmospheric response to short and long term solar UV variations: analysis of observations and 2D model results

We have investigated the middle atmospheric response to the 27-day and 11-yr solar UV flux variations at low to middle latitudes using a two-dimensional photochemical model. The model reproduced most features of the observed 27-day sensitivity and phase lag of the profile ozone response in the upper stratosphere and lower mesosphere, with a maximum sensitivity of +0.51% per 1% change in 205 nm flux. The model also reproduced the observed transition to a negative phase lag above 2 mb, reflecting the increasing importance with height of the solar modulated HO_x chemistry on the ozone response above 45 km. The rnodel revealed the general anti-correlation of ozone and solar UV at 65–75 km, and simulated strong UV responses of water vapor and HO_x species in the mesosphere. Consistent with previous 1D model studies, the observed upper mesospheric positive ozone response averaged over ±40° was simulated only when the model water vapor concentrations above 75 km were significantly reduced relative to current observations. Including the observed temperature-UV response in the model to account for temperature-chemistry feedback improved the model agreement with observations in the middle mesosphere, but did not improve the overall agreement above 75 km or in the stratosphere for all time periods considered. Consistent with the short photochemical time scales in the upper stratosphere, the model computed ozone-UV sensitivity was similar for the 27-day and 11-yr variations in this region. However, unlike the 27-day variation, the model simulation of the 11-yr solar cycle revealed a positive ozone-UV response throughout the mesosphere due to the large depletion of water vapor and reduced HO_x-UV sensitivity. A small negative ozone response at 65–75 km was obtained in the 11-yr simulation when temperature-chemistry feedback was included,In agreement with observations, the model computed a low to middle latitude total ozone phase lag of +3 days and a sensitivity of +0.077% per 1% change in 205 nm flux for the 27-day solar variation, and a total ozone sensitivity of +0.27% for the 11-yr solar cycle. This factor of 3 sensitivity difference is indicative of the photochemical time constant for ozone in the lower stratosphere which is comparable to the 27-day solar rotation period but is much shorter than the 11-yr solar cycle.     

The geomagnetic time and position of a terrestrial station

The concepts of geomagnetic time and position of a station on Earth are reviewed on the basis of the centred dipole, and the eccentric dipole, magnetic field approximations. Equations are presented from which the centred dipole coordinates can be computed as a special case of the eccentric dipole coordinates. It is also shown that several aspects relating to geomagnetism appear to vary nearly linearly with time and are well represented by linear regression equations which can significantly simplify subsequent computations. Sufficient information is included so that magnetic time and position for any station on Earth may be calculated. Sample results are presented which specifically relate to Scott Base, Antarctica.     

The changing biosphere: recent insights from paleoenvironmental science into drivers,mechanisms and impacts

Paleoenvironmental science has experienced a recent surge in interest and activity as concerns grow over global environmental change. Key research questions in the biotic realm of paleoenvironmental science focus on explaining climatic change at time scales of decades to centuries and understanding ecosystem responses to these changes. Biotic responses are increasingly being studied at smaller spatial scales to identify local factors that determine the sensitivity of a particular system to climatic change. These findings can then be applied to solving a variety of problems, such as setting conservation targets or testing mechanisms for observed climatic and biogeographic phenomena. Research approaches commonly used today include hypothesis testing, which has now become more sophisticated as paleoecologists and paleoclimatologists integrate with modellers. Other frameworks involve the quantitative integration of multiple proxy indicators and the use of extensive publicly available data networks to produce new datasets for paleoclimatic reconstructions and other applications.