36 research outputs found

    A Comparison of Flare Forecasting Methods. III. Systematic Behaviors of Operational Solar Flare Forecasting Systems

    Get PDF
    A workshop was recently held at Nagoya University (31 October – 02 November 2017), sponsored by the Center for International Collaborative Research, at the Institute for Space-Earth Environmental Research, Nagoya University, Japan, to quantitatively compare the performance of today’s operational solar flare forecasting facilities. Building upon Paper I of this series (Barnes et al. 2016), in Paper II (Leka et al. 2019) we described the participating methods for this latest comparison effort, the evaluation methodology, and presented quantitative comparisons. In this paper we focus on the behavior and performance of the methods when evaluated in the context of broad implementation differences. Acknowledging the short testing interval available and the small number of methods available, we do find that forecast performance: 1) appears to improve by including persistence or prior flare activity, region evolution, and a human “forecaster in the loop”; 2) is hurt by restricting data to disk-center observations; 3) may benefit from long-term statistics, but mostly when then combined with modern data sources and statistical approaches. These trends are arguably weak and must be viewed with numerous caveats, as discussed both here and in Paper II. Following this present work, we present in Paper IV a novel analysis method to evaluate temporal patterns of forecasting errors of both types (i.e., misses and false alarms; Park et al. 2019). Hence, most importantly, with this series of papers we demonstrate the techniques for facilitating comparisons in the interest of establishing performance-positive methodologies

    Understanding space weather to shield society: A global road map for 2015-2025 commissioned by COSPAR and ILWS

    Get PDF
    There is a growing appreciation that the environmental conditions that we call space weather impact the technological infrastructure that powers the coupled economies around the world. With that comes the need to better shield society against space weather by improving forecasts, environmental specifications, and infrastructure design. [...] advanced understanding of space weather requires a coordinated international approach to effectively provide awareness of the processes within the Sun-Earth system through observation-driven models. This roadmap prioritizes the scientific focus areas and research infrastructure that are needed to significantly advance our understanding of space weather of all intensities and of its implications for society. Advancement of the existing system observatory through the addition of small to moderate state-of-the-art capabilities designed to fill observational gaps will enable significant advances. Such a strategy requires urgent action: key instrumentation needs to be sustained, and action needs to be taken before core capabilities are lost in the aging ensemble. We recommend advances through priority focus (1) on observation-based modeling throughout the Sun-Earth system, (2) on forecasts more than 12 hrs ahead of the magnetic structure of incoming coronal mass ejections, (3) on understanding the geospace response to variable solar-wind stresses that lead to intense geomagnetically-induced currents and ionospheric and radiation storms, and (4) on developing a comprehensive specification of space climate, including the characterization of extreme space storms to guide resilient and robust engineering of technological infrastructures. The roadmap clusters its implementation recommendations by formulating three action pathways, and outlines needed instrumentation and research programs and infrastructure for each of these. [...]Comment: In press for Advances of Space Research: an international roadmap on the science of space weather, commissioned by COSPAR and ILWS (63 pages and 4 figures

    St. Patrick’s Day 2015 geomagnetic storm analysis based on Real Time Ionosphere Monitoring

    Get PDF
    A detailed analysis is presented for the days in March, 2015 surrounding St. Patrick’s Day 2015 geomagnetic storm, based on the existing real-time and near real-time ionospheric models (global or regional) within the group, which are mainly based on Global Navigation Satellite Systems (GNSS) and ionosonde data. For this purpose, a variety of ionospheric parameters is considered, including Total Electron Content (TEC), F2 layer critical frequency (foF2), F2 layer peak (hmF2), bottomside halfthickness (B0) and ionospheric disturbance W-index. Also, ionospheric high-frequency perturbations such as Travelling Ionospheric Disturbances (TIDs), scintillations and the impact of solar flares facing the Earth will be presented to derive a clear picture of the ionospheric dynamicsPostprint (published version

    Is there a causal relationship between cosmic noise absorption and PMSE?

    No full text
    Copyright 2005 by the American Geophysical Union.We report on the first Southern Hemisphere comparison between polar mesosphere summer echoes (PMSE) and cosmic noise absorption (CNA). Observations were obtained during the austral summer of 2003–2004 from a 55 MHz MST radar, a 38.2 MHz imaging riometer and a 30 MHz standard riometer all co-located at Davis, Antarctica (68.6°S). Case study PMSE events suggest that CNA plays a role in the intensification of established dayside PMSE possibly linked with soft electron precipitation from the polar cusp, and indeed with a similar effect and moreover with the creation of night-side PMSE connected with hard auroral electron precipitation. Although Pearson correlation coefficients are not that high (i.e., 0.423), Spearman rank correlation coefficients of 0.315, with 123 degrees of freedom well above the 99% confidence limits, established that a weak correlation between CNA and PMSE intensity exists. We use this result to discuss two unexplained properties of PMSE: (i) diurnal minimum near ∼15–21 UT; and (ii) non-linear intensity variation as a function of latitude. Surprisingly, this study presents only the second analysis of this kind using co-located instruments.Ray J. Morris, Michael B. Terkildsen, David A. Holdsworth, Mike R. Hyd

    Occurrence rate and duration of space weather impacts on high-frequency radio communication used by aviation

    No full text
    High frequency (HF) radio wave propagation is sensitive to space weather-induced ionospheric disturbances that result from enhanced photoionization and energetic particle precipitation. Recognizing the potential risk to HF radio communication systems used by the aviation industry, as well as potential impacts on GNSS navigation and the risk of elevated radiation levels, the International Civil Aviation Organization (ICAO) initiated the development of a space weather advisory service. For HF systems, this service specifically identifies shortwave fadeout, auroral absorption, polar cap absorption, and post-storm maximum useable frequency depression (PSD) as phenomena impacting HF radio communication and specifies moderate and severe event thresholds to describe event severity. This paper examines the occurrence rate and duration of events crossing the moderate and severe thresholds. Shortwave fadeout was evaluated based on thresholds in the solar X-ray flux. Analysis of 40-years of solar X-ray flux data showed that moderate and severe level solar X-ray flares were observed, on average, 123 and 5 times per 11-year solar cycle, respectively. The mean event duration was 68 min for moderate level events and 132 min for severe level events. Auroral absorption events crossed the moderate threshold for 40 events per solar cycle, with a mean event duration of 5.1 h. The severe threshold was crossed for 3 events per solar cycle with a mean event duration of 12 h. Polar cap absorption had the longest mean duration at ~8 h for moderate events and 1.6 days for severe events; on average, 24 moderate and 13 severe events were observed per solar cycle. Moderate and severe thresholds for shortwave fadeout, auroral absorption, and polar cap absorption were used to determine the expected impacts on HF radio communication. Results for polar cap absorption and shortwave fadeout were consistent with each other, but the expected impact for auroral absorption was shown to be 2–3 times higher. Analysis of 22 years of ionosonde data showed moderate, and severe PSD events occurred, on average, 200 and 56 times per 11-year solar cycle, respectively. The mean event duration was 5.5 h for moderate-level events and 8.5 h for severe-level events. During solar cycles 22 and 23, HF radio communication was expected to experience moderate or severe impacts due to the ionospheric disturbances caused by space weather, a maximum of 163 and 78 days per year, respectively, due to the combined effect of absorption and PSD. The distribution of events is highly non-uniform with respect to the solar cycle: 70% of moderate or severe events were observed during solar maximum compared to solar minimum

    Mental well-being and patient activation during the first eight months of the COVID-19 pandemic in Denmark - a cohort study among 710 Danish adults with chronic conditions

    No full text
    Abstract Background COVID-19 has highlighted the importance of patient activation in managing chronic conditions and promoting resilience during times of crisis. Patient activation refers to an individual’s knowledge, skills, and confidence in managing their own health and healthcare. Previous research has shown that people with higher levels of patient activation are better prepared to navigate the challenges of chronic illness and are more likely to engage in healthy behaviors. However, the impact of patient activation on COVID-19-related concerns and mental well-being among people with chronic conditions during the pandemic remains unclear. This study aims to investigate the possible role of patient activation in shaping COVID-19-related concerns and to describe changes in mental well-being among Danish adults with one or more chronic conditions during the early months of the pandemic. Methods Danish adults with chronic conditions (e.g. diabetes, coronary heart disease, obstructive pulmonary lung disease, cancer) who had participated in a municipal health education program prior to the COVID-19 outbreak were asked to participate in this prospective questionnaire study in May 2020 and November 2020. Sociodemographic (sex, age, living status, educational attainment, employment status) and disease-related information (diagnosis, one or more chronic conditions) along with the Patient Activation Measure were collected before the outbreak and were obtained from a clinical database used for monitoring and evaluation of municipal health education programs. In contrast, the two questionnaires collected six months apart consisted of single items related to concerns about COVID-19 and the WHO-5 well-being index. Results A total of 710 people with chronic conditions (mean age 60.9 years; 55.8% female) participated at both time points. In bivariate analyses, patient activation was associated with COVID-19-related concern and well-being. At follow-up, participants experienced a significant decrease in well-being. The decrease was associated with poorer well-being measured six months earlier, a greater perception that it had become more challenging to take care of one’s health due to the pandemic, and finally, feeling lonely. The association between patient activation and well-being ceased to be significant in the multivariate regression model. Conclusions A considerable proportion of people with chronic conditions participating in this study have been mentally burdened during COVID-19. Although lower levels of patient activation were associated with greater COVID-19-related concerns, it did not have a significant impact on mental well-being over time

    Unseasonal development of post-sunset F-region irregularities over Southeast Asia on 28 July 2014: 1. Forcing from above?

    No full text
    Abstract This contribution is the first of a two-part investigation into an unseasonal post-sunset equatorial F-region irregularity (EFI) event over the Southeast Asian region on the evening of 28 July 2014. Ground-based GPS scintillation data, space-based GPS radio occultation (RO) data, and ionosonde data show the existence of EFIs shortly after sunset over a region spanning 30° in longitude and 40° in latitude, centered on the geomagnetic equator. This post-sunset EFI event was observed during a time of the year when post-sunset equatorial plasma bubbles (EPBs) are very infrequent in the Southeast Asian longitude sector. GPS RO data shows that the EFI event over Southeast Asia coincided with the suppression of peak-season EPBs in the African and Pacific longitude sectors. Ionosonde data shows the presence of a strong pre-reversal enhancement (PRE) in the upward plasma drift over Southeast Asia prior to the detection of EFIs. Further, it is reported that this PRE was significantly stronger than on any other day of July 2014. An analysis of the geophysical conditions during this event reveals that this enhanced PRE was not caused by disturbed geomagnetic activity. Therefore, it is hypothesized that forcing from lower altitudes, perhaps tidal/planetary waves, was the potential cause of this strong PRE, and the subsequent EPB/EFI activity, on this day over the Southeast Asian sector
    corecore