Predictability of Geomagnetically Induced Currents using neural networks

It is a well documented fact that Geomagnetically Induced Currents (GIC’s) poses a significant threat to ground-based electric conductor networks like oil pipelines, railways and powerline networks. A study is undertaken to determine the feasibility of using artificial neural network models to predict GIC occurrence in the Southern African power grid. The magnitude of an induced current at a specific location on the Earth’s surface is directly related to the temporal derivative of the geomagnetic field (specifically its horizontal components) at that point. Hence, the focus of the problem is on the prediction of the temporal variations in the horizontal geomagnetic field (@Bx/@t and @By/@t). Artificial neural networks are used to predict @Bx/@t and @By/@t measured at Hermanus, South Africa (34.27◦ S, 19.12◦ E) with a 30 minute prediction lead time. As input parameters to the neural networks, insitu solar wind measurements made by the Advanced Composition Explorer (ACE) satellite are used. The results presented here compare well with similar models developed at high-latitude locations (e.g. Sweden, Finland, Canada) where extensive GIC research has been undertaken. It is concluded that it would indeed be feasible to use a neural network model to predict GIC occurrence in the Southern African power grid, provided that GIC measurements, powerline configuration and network parameters are made available

First results of the SA Agulhas II mobile mini-neutron monitor: Instrumental characterization and environmental sensitivity

We present the first results of a new redesigned version of the mini-neutron monitor installed on the South African Research vessel, the SA Agulhas II. Measurements taken from the 2019/2020 relief voyages are presented. We show that the instrument is very sensitive to temperature variations when the ambient temperature is below 3oC. This is believed to be an instrumental effect. Additionally, we show the presence of high-frequency interference in the calculated waiting time distributions when the vessel reaches polar latitudes. We show that these periodic variations are only present in the intensity of secondary atmospheric particles and most likely related to the operation of the vessel’s ice radar. We are currently looking at moving the instrument to a more suitable location on board the SA Agulhas II where we will hopefully be able to operate the instrument in a continuous fashion for several years to come

Validating the LDi and LCi Indices in the Southern Hemisphere

The validation of the Local Disturbance index (LDi) and its first time derivative Local Current index (LCi) is performed in the Southern Hemisphere. Two South African magnetic observatories, Hermanus and Hartebeesthoek contributed data for this study, and two South African power stations, Grassridge and Matimba, provided geomagnetically induced current (GIC) data. This validation focused on two major geomagnetic storms, Halloween and Saint Patrick's Day events that occurred in October 2003 and March 2015, respectively. The comparative evaluation of the LDi and LCi indices was executed with the help of the local horizontal component (H) and also comparing them to the global index SYM-H. A direct comparison to measured GIC shows that LCi performs slightly better than dH/dt as a proxy for GIC. The comparison of the LDi 1-hr magnetic disturbances values to ones calculated applying a Linear phase Robust Non-Smoothing method to the H component yields a Pearson correlation coefficient R greater than 0.960 for different groups of magnetic storms based on intensity. The estimated SYM-H index from LDi data showed a possible difference of about 300 nT from the published SYM-H index values around 20:00 UT on 29 October 2003, during the Halloween storm. This study has shown that the LDi and LCi indices, developed in the Northern Hemisphere, can be calculated at similar latitudes in the Southern Hemisphere for studying local space weather conditions and now-casting successfully local geomagnetic events.Agencia Estatal de Investigació

Observations from SANSA’s geomagnetic network during the Saint Patrick’s Day storm of 17–18 March 2015

Geomagnetic storms are space weather events that result in a temporary disturbance of the earth’s magnetosphere caused by a solar wind that interacts with the earth’s magnetic field. We examined more closely how some southern African magnetic observatories responded to the Saint Patrick’s Day storm using local K-indices. We show how this network of observatories may be utilised to model induced electric field, which is useful for the monitoring of geomagnetically induced anomalous currents capable of damaging power distribution infrastructure. We show an example of the correlation between a modelled induced electric field and measured geomagnetically induced currents in southern Africa. The data show that there are differences between global and local indices, which vary with the phases of the storm. We show the latitude dependence of geomagnetic activity and demonstrate that the direction of the variation is different for the X and Y components. Significance: • The importance of ground-based data in space weather studies is demonstrated. • We show how SANSA’s geomagnetic network may be utilised to model induced electric field, which is useful for the monitoring of geomagnetically induced anomalous currents capable of damaging power distribution infrastructure. Open data set:  http://www.intermagnet.org/data-donnee/download-eng.ph

The Wooster Voice (Wooster, OH), 1946-10-04

The football team has sustained an abundance of injuries over the past week. Both staff and students are having difficulties with not have enough housing spaces, nor enough classrooms. The first year senate chair will be Don Shawver. Students have voted in favor for having a homecoming queen by 757 for and 128 against. On the thirteenth of October, the Inter-Club Council will be hosting a tea for any freshman girl who is interested in joining a section. A feature is written about how a Latin American student views the College of Wooster. Emory Anderson writes about how squirrels are slowly dominating the world.https://openworks.wooster.edu/voice1941-1950/1128/thumbnail.jp

The faunistic diversity of spiders (Arachnida : Araneae) of the South African grassland biome

As part of the South African National Survey of Arachnida (SANSA), all available information on spider species distribution in the South African Grassland Biome was compiled. A total of 11 470 records from more than 900 point localities were sampled in the South African Grassland Biome until the end of 2011, representing 58 families, 275 genera and 792 described species. A further five families (Chummidae, Mysmenidae, Orsolobidae, Symphytognathidae and Theridiosomatidae) have been recorded from the biome but are only known from undescribed species. The most frequently recorded families are the Gnaphosidae (2504 records), Salticidae (1500 records) and Thomisidae (1197 records). The last decade has seen an exponential growth in the knowledge of spiders in South Africa, but there are certainly many more species that still have to be discovered and described. The most species-rich families are the Salticidae (112 spp.), followed by the Gnaphosidae (88 spp.), Thomisidae (72 spp.) and Araneidae (52 spp.). A rarity index, taking into account an endemicity index and an abundance index, was determined to give a preliminary indication of the conservation importance of each species. The endemicity index indicates that 58 species are endemic to the biome, while 38 species could be considered to be introduced, cosmopolitan, or having a distribution extending beyond the Afrotropical Region. Levels of endemism are highest for mygalomorph trapdoor spiders (7.14–50%) and selected araneomorph families with restricted dispersal capabilities (i.e. Archaeidae, Sicariidae and Scytodidae). A brief review of the published data of surveys from the biome and the patterns of spider assemblage structure in each is presented, together with information on the most species-rich spider families occurring in the biome.The Agricultural Research Council (ARC) and the South African National Biodiversity Institute (SANBI). Threatened Species Programme are thanked for generously funding SANSA Phase II. The National Research Foundation (NRF). SHF acknowledges financial assistance from the DST-NRF Centre of Excellence for Invasion Biology.http://www.tandfonline.com/loi/ttrs20hb2013ab201