Large solar flares and their ionospheric D region enhancements


first_imgOn 4 November 2003, the largest solar flare ever recorded saturated the GOES satellite X-ray detectors, making an assessment of its size difficult. However, VLF radio phase advances effectively recorded the lowering of the VLF reflection height and hence the lowest edge of the Earth’s ionosphere. Previously, these phase advances were used to extrapolate the GOES 0.1–0.8 nm (“XL”) fluxes from saturation at X17 to give a peak magnitude of X45 ± 5 for this great flare. Here it is shown that a similar extrapolation, but using the other GOES X-ray band, 0.05–0.4 nm (“XS”), is also consistent with a magnitude of X45. Also reported here are VLF phase measurements from two paths near dawn: “Omega Australia” to Dunedin, New Zealand (only just all sunlit) and NPM, Hawaii, to Ny Alesund, Svalbard (only partly sunlit), which also give remarkably good extrapolations of the flare flux, suggesting that VLF paths monitoring flares do not necessarily need to be in full daylight. D region electron densities are modeled as functions of X-ray flux up to the level of the great X45 flare by using flare-induced VLF amplitudes together with the VLF phase changes. During this great flare, the “Wait” reflection height, H′, was found to have been lowered to ∼53 km or ∼17 km below the normal midday value of ∼70 km. Finally, XL/XS ratios are examined during some large flares, including the great flare. Plots of such ratios against XL can give quite good estimates of the great flare’s size (X45) but without use of VLF measurements.last_img read more

The agile dashboard


first_img This post is currently collecting data… Executives use dashboards to monitor the performance and health of our businesses. Traditional metrics like sales, revenue, margin, return on equity and total shareholder return are common and important metrics. But today, in the age of disruption, do we need different, more forward-looking metrics to indicate if our business is agile enough to win the marketplace tomorrow?The Agile Dashboard was developed to help organizations address this gap by creating a set of more forward-looking, predictive metrics centered on: speed, interactivity and pivot. This video features Joe Perfetti, innovation fellow, Duke Corporate Education, and lecturer with the RH Smith School of Business at the University of Maryland.The discussion explains why speed, the level and type of interactivity with customers and the external environment, and the ability to pivot are the building blocks of agility. It also provides the metrics for each and examples of their applicability in organizations. This is placeholder text continue reading »center_img ShareShareSharePrintMailGooglePinterestDiggRedditStumbleuponDeliciousBufferTumblrlast_img read more

Full-time SRO coming to BCSC next year


first_imgBatesville, Ind. — The Batesville Community School Corporation will add a full-time school resource officer for the 2017-18 school year.Superintendent Paul Ketcham says the position will not only enforce rules and provide security but will also serve as a mentor, role model and counselor for students, faculty and parents.School board members unanimously approved the job description at the most recent meeting.The position will be funded with matching grant dollars from the Department of Homeland Security.Schools in Flint, Michigan established the first school resource officer program in 1953.last_img read more