ALBERT

Description: Cover. Evolving and increasingly hazardous radiation levels in space. (top) ACE dose rates (red) are based on fits to CRIS spectra [ O'Neill , 2006]; CRaTER measurements (green) from the zenith-facing D1/D2 detectors are used as proxies for lens dose rates behind 0.3 g/cm2 Al shielding Schwadron et al . [2012]. The sunspot number predictions (the lower black and blue dashed lines) show two cases based on a Gleissberg-like and a Dalton-like minimum, the results of which are similar. The dose predictions (solid blue line and the upper black and blue dashed lines) are from a sunspot-based model of the heliospheric magnetic field and the correlated variation in modulation of GCRs. The ACE data, CRaTER data, and model results are projected to the lunar surface. (bottom) Same as the top panel, but for a longer time span. See pp. 622–632.

Description: Shortly after NASA's Mars Atmosphere and Volatile EvolutioN mission (MAVEN) spacecraft entered Mars’ orbit on Sept 21, 2014, scientists glimpsed the Martian atmosphere's response to a front of solar energetic particles (SEPs) and an associated coronal mass ejection (CME). In response to some solar flares and CMEs, streams of SEPs burst from the solar atmosphere and are further accelerated in the interplanetary medium between the Sun and the planets. These particles deposit their energy and momentum into anything in their path, including the Martian atmosphere and MAVEN particle detectors.

Description: Satellite Based Augmentation Systems (SBASes) are designed to provide additional accuracy and robustness to existing satellite-based radio navigation systems for all phases of a flight. However, similar to navigation systems such as GPS which has proven its worth for the investigation of the ionosphere, the SBASes do have certain advantages. In the present paper, we propose and demonstrate SBAS applicability to ionospheric and space weather research in a novel and cost-effective way. The recent commissioning of the Indian SBAS, named GPS Aided Geo Augmented Navigation (GAGAN), covering the equatorial and low-latitude regions centered around the Indian longitudes provides the motivation for this approach. Two case studies involving different ionospheric behavior over low-latitude regions vindicate the potential of SBAS over extended areas.

Description: Key Points Announcement of 13th international Spacecraft Charging Technology Conference Website for abstracts and registration is open Contact authors if any questions

Description: Cover. In Shiota et al . doi: 10.1002/2013SW000989 , (a) 3D view of coordinates in simulation. Background colors on the transparent XY plane (the solar equatorial plane) show solar wind velocity distribution. Positions of planets andtheir orbits on Oct. 26 (day 300) of 2008 are shown as colored spheres and tubes. Among them, clear ones are located above (north of) the transparent plane. Color on central sphere shows 2D distribution of magnetic field radial components. Its color bar is shown in the panel (b). (b) 3D view of sector boundary of interplanetary magnetic field (white surface). In the area north of the boundary, the IMF is directed toward the Sun (Br 〈 0). (c) 3D views of sector boundary and solar wind on ecliptic plane (transparent plane). See pp. 187–204.

Description: Accurate galactic cosmic ray (GCR) models are required to assess crew exposure during long duration missions to the moon or Mars. Many of these models have been developed and compared to available measurements, with uncertainty estimates usually stated to be less than 15%. However, when the models are evaluated over a common epoch and propagated through to effective dose, relative differences exceeding 50% are observed. This indicates that the metrics used to communicate GCR model uncertainty can be better tied to exposure quantities of interest for shielding applications. This is the first of three papers focused on addressing this need. In this work, the focus is on quantifying the extent to which each GCR ion and energy group, prior to entering any shielding material or body tissue, contributes to effective dose behind shielding. Results can be used to more accurately calibrate model free parameters and provide a mechanism for refocusing validation efforts on measurements taken over important energy regions. Results can also be used as a reference to guide future nuclear cross section measurements and radiobiology experiments. It is found that GCR with Z 〉 2 and boundary energies below 500 MeV/n induce less than 5% of the total effective dose behind shielding. This finding is important given that most of the GCR models are developed and validated against ACE/CRIS measurements taken below 500 MeV/n. It is therefore possible for two models to very accurately reproduce the ACE/CRIS data while inducing very different effective dose values behind shielding.

Description: In order to assess the astronaut exposure received within vehicles or habitats, accurate models of the ambient GCR environment are required. Many models have been developed and compared to measurements, with uncertainty estimates often stated to be within 15%. However, inter-code comparisons can lead to differences in effective dose exceeding 50%. This is the second of three papers focused on resolving this discrepancy. The first paper showed that GCR heavy ions with boundary energies below 500 MeV/n induce less than 5% of the total effective dose behind shielding. Yet, due to limitations on available data, model development and validation is heavily influenced by comparisons to measurements taken below 500 MeV/n. In the current work, the focus is on developing an efficient method for propagating uncertainties in the ambient GCR environment to effective dose values behind shielding. A simple approach utilizing sensitivity results from the first paper is described and shown to be equivalent to a computationally expensive Monte Carlo uncertainty propagation. The simple approach allows a full uncertainty propagation to be performed once GCR uncertainty distributions are established. This rapid analysis capability may be integrated into broader probabilistic radiation shielding analysis and also allows error bars (representing boundary condition uncertainty) to be placed around point estimates of effective dose.

Description: This is the last of three papers focused on quantifying the uncertainty associated with GCR models used for space radiation shielding applications. In the first paper, it was found that GCR ions with Z 〉 2 and boundary energy below 500 MeV/n induce less than 5% of the total effective dose behind shielding. This is an important finding since GCR model development and validation has been heavily biased towards ACE/CRIS measurements below 500 MeV/n. Weights were also developed that quantify the relative contribution of defined GCR energy and charge groups to effective dose behind shielding. In the second paper, it was shown that these weights could be used to efficiently propagate GCR model uncertainties into effective dose behind shielding. In this work, uncertainties are quantified for a few commonly used GCR models. A validation metric is developed that accounts for measurements uncertainty, and the metric is coupled to the fast uncertainty propagation method. For this work, the Badhwar-O'Neill (BON) 2010 and 2011 and the Matthia GCR models are compared to an extensive measurement database. It is shown that BON2011 systematically over-estimates heavy ion fluxes in the range 0.5-4 GeV/n. The BON2010 and BON2011 also show moderate and large errors in reproducing past solar activity near the 2000 solar maximum and 2010 solar minimum. It is found that all three models induce relative errors in effective dose in the interval [-20%, 20%] at a 68% CL. The BON2010 and Matthia models are found to have similar overall uncertainty estimates and are preferred for space radiation shielding applications.

Description: [1]  The ionospheric variability found at auroral locations is usually assumed to be unpredictable. The magnetosphere, which drives this ionospheric variability via storms and substorms, is at best only qualitatively describable. In this study we demonstrate that over a three-year period, ionospheric variability observed from Poker Flat, Alaska has, in fact, a high degree of long-term predictability. The observations used in this study are (a) the solar wind High Speed Stream (HSS) velocity measured by the NASA Advanced Composition Explorer (ACE) satellite, used to define the Corotating Interaction Region (CIR); and (b) the ion temperature at 300-km altitude measured by the NSF Poker Flat Incoherent Scatter Radar (PFISR) over Poker Flat, Alaska. After determining a seasonal and diurnal climatology for the ion temperature, we show that the residual ion temperature heating events occur synchronously with CIR-geospace interactions. Furthermore, we demonstrate examples of ion temperature forecasting at 27, 54, and 81 days. A rudimentary operational forecasting scenario is described for forecasting recurrence 27 days ahead for CIR-generated geomagnetic storms. These forecasts apply specifically to satellite tracking operations (thermospheric drag) and emergency HF-radio communications (ionospheric modifications) in the polar regions. The forecast is based on present day solar and solar-wind observations that can be used to uniquely identify the coronal hole and its CIR. From this CIR epoch, a 27-day forecast is then made.

Description: No abstract is available for this article.

Description: Key Points Announcement of SEP Measurements Intercalibration Workshop In association with the Space Weather Workshop, Boulder, CO Contact authors with attendance plans and titles of talks

Description: Key Points Introduction to the FORECAST Special Section

Description: The Earth's Ionosphere-Thermosphere-Electrodynamics (I-T-E) system varies markedly on a range of spatial and temporal scales and these variations have adverse effects on human operations and systems, including High-Frequency (HF) communications, over-the-horizon radars, and survey and navigation systems that use Global Positioning System (GPS) satellites. Consequently, there is a need to elucidate the underlying physical processes that lead to space weather disturbances and to both mitigate and forecast near-Earth space weather. The meteorologists and oceanographers have shown that data assimilation models are superior to global physics-based models for specifications and forecasts, but only during the last 15 years have they been used for near-Earth investigations as more global (space and ground-based) measurements became available. Although data assimilation models produce better specifications and forecasts than global physics-based models, there is still a spread in results for a given simulation scenario when different data assimilation models are used. This spread occurs because the different data assimilation models use different data types, data amounts, assimilation techniques, and background physics-based models. This data assimilation issue is being addressed with the launching of the ‘NASA/NSF Space Weather Modeling Collaboration’ program. Currently, our team has 7 physics-based data assimilation models for the ionosphere, plasmasphere, thermosphere, and electrodynamics. These models assimilate a myriad of different ground- and space-based observations, and there is more than one data assimilation model for each near-Earth space domain. These data assimilation models are being used to create a Multimodel Ensemble Prediction System (MEPS) , which will allow ensemble modeling of the I-T-E system with different data assimilation models that are based on different physical assumptions, assimilation techniques, and initial conditions. The application of ensemble modeling with several different data assimilation models will lead to a paradigm shift in how basic physical processes are studied in near-Earth space, and it is expected to lead to a significant advance in space weather specifications and forecasts.

Description: We developed a magnetohydrodynamic (MHD) solar wind model which can be used for practical use in real-time space weather forecasting at Earth's orbit and those of other planets. The MHD simulation covering three years (2007 - 2009) was performed to test the accuracy, and the numerical results show reasonable agreement with in situ measurements of the solar wind at Earth's orbit and with measurements at Venus and Mars by Venus Express and Mars Express, respectively. The comparison also shows that the numerical results can be used to detect stream interfaces, which is useful for space weather forecast of killer electrons in the outer Van Allen belt.

Description: To forecast geomagnetic storms we had examined initially-observed parameters of coronal mass ejections (CMEs) and introduced an empirical storm forecast model in a previous study (Kim et al. 2010). Now, we suggest a two-step forecast considering not only CME parameters observed in the solar vicinity, but also solar wind conditions near Earth to improve the forecast capability. We consider the empirical solar wind criteria derived in this study (B z ≤ -5 nT or E y ≥ 3 mV/m fort ≥ 2 hr for moderate storms with minimum Dst less than −50 nT) and a Dst model developed by Temerin and Li (TL model, 2002; 2006). Using 55 CME-Dst pairs during 1997 to 2003, our solar wind criteria produces slightly better forecasts for 31 storm events (90%) than the forecasts based on the TL model (87%). However, the latter produces better forecasts for 24 non-storm events (88%), while the former correctly forecasts only 71% of them. We then performed the two-step forecast. The results are as follows: i) for 15 events that are incorrectly forecasted using CME parameters, 12 cases (80%) can be properly predicted based on solar wind conditions; ii) if we forecast a storm when both CME and solar wind conditions are satisfied (⋂), the critical sucess index (CSI) becomes higher than that from the forecast using CME parameters alone, however, only 25 storm events (81%) are correctly forecasted; iii) if we forecast a storm when either set of these conditions is satisfied (⋃), all geomagnetic storms are correctly forecasted.

Description: Cover. Sojka et al. doi: 10.1002/2013SW001012 provided an image of binned ACE solar wind velocity organized into 27 day Bartels' Rotation Numbers and hourly within each 27 days of that rotation. The wind magnitude is color coded and a secondary axis provides year information beginning 1 January 2007.

Description: Understanding the capability of a simulation to reproduce observed features is a requirement for its use in operational space weather forecasting. We compare statistically ionospheric seasonal variations in the Grand Unified Magnetosphere-Ionosphere Coupling Simulation (GUMICS-4) global magnetohydrodynamic (MHD) model with measurements. The GUMICS-4 data consists of a set of runs that was fed with real solar wind measurements and covers the period of one year. Ionospheric convection measurements arefrom the SuperDARN radars, and electric currents are derived from the magnetic field measured by the CHAMP satellite. Auroral electrojet indices are used to examine the disturbance magnetic field on ground. The signatures of electrodynamic coupling between the magnetosphere and ionosphere extend to lower latitudes in GUMICS-4 than in observations, and key features of the auroral ovals — the Region 2 field-aligned currents, electrojets, Harang discontinuity, and ring of enhanced conductivity— are not properly reproduced. The ground magnetic field is even at best about 5 times weaker than measurements, which can be a problem for forecasting geomagnetically induced currents. According to the measurements, the ionospheric electrostatic potential does not change significantly from winter to summer but field-aligned currents enhance, whereas in GUMICS-4, the electrostatic potential weakens from winter to summer but field-aligned currents do not change. This could be a consequence of the missing Region 2 currents: the Region 1 current has to close with itself across the polar cap, which makes it sensitive to solar UV conductivity. Precipitation energy and conductance peak amplitudes in GUMICS-4 agree with observations.

Description: Ground magnetic field variations can induce electric currents on long conductor systems such as high-voltage power transmission systems. The extra electric currents can interfere with normal operation of these conductor systems and thus there is a greatneed for better specification and prediction of the field perturbations. In this publication we present CalcDeltaB, an efficient post-processing tool to calculate magnetic perturbations Δ B at any position on the ground from snapshots of the current systems that are being produced by first-principles models of the global magnetosphere-ionosphere system. This tool was developed during the recent “dB/dt” modeling challenge at the Community Coordinated Modeling Center that compared magnetic perturbations and their derivative with observational results. The calculation tool is separate from each of the magnetosphere models and ensures that the Δ B computation method is uniformly applied and that validation studies using Δ B compare the performance of the models rather than the combination of each model and a built-in Δ B computation tool that may exist. Using the tool, magnetic perturbations on the ground are calculated from currents in the magnetosphere, from field-aligned currents between magnetosphere and ionosphere, and the Hall- and Pedersen currents in the ionosphere. The results of the new post-processing tool are compared with Δ B calculations within the Space Weather Modeling Framework (SWMF) model and are in excellent agreement. We find that a radial resolution of 1/30 R E is fine enough to represent the contribution to Δ B from the region of field aligned currents.

Description: Space weather is listed as a natural disaster by the Federal Emergency Management Agency of the United States ( www.ready.gov/space-weather ). The advancement of space weather research has become imperative since the advent of technologies vulnerable to its impacts. Astronauts during space station operations, satellite and radio communications, to name a few, are adversely affected by space weather. In Japan, early works (1950s) focused on the ionospheric disturbances that disrupt radio wave communications. During the International Geophysical Year (1957–1958), scientists at the Radio Research Laboratory discovered a correlation between solar bursts and short-wave fadeouts [ Nishida , 2010]. This made the sun an important subject matter of investigation. In 1998, the National Astronomical Observatory of Japan established a program on solar studies utilizing the facilities at Nobeyama Radio Observatory [ Kumar , 2007]. In order to support the development of an early warning system for space weather irregularities and space debris problems, the Space Environment Research Center (SERC) of Kyushu University (KU) was established in 2002 to carry out basic science research under the direction of Kiyohumi Yumoto. In 2005, the construction of a global array of magnetometers called MAGnetic Data Acquisition System/Circum-pan Pacific Magnetometer Network (MAGDAS/CPMN) was initiated [ Yumoto and STPP Sub-Committee , 2009]. As of 2014, there are 72 stations worldwide monitoring the Earth's magnetic field globally (Figure 1). Also in 2005, joining in the research effort is the project " Basic Study of Space Weather prediction " , which was supported by the Ministry of Education, Culture, Sports, Science and Technology of Japan. Kazunari Shibata led this 5-year project to find answers to fundamental questions of space weather science in order to develop a physical model of the coupling processes in the solar-terrestrial interaction [Shibata and Kamide, 2007]. Researches in forecasting space weather phenomena continued to rise [ Tsubouchi and Omura , 2007; Yamamoto and Sakurai , 2009; Nóse et al ., 2012; Sakaguchi et al ., 2013]. At present, the Space Weather and Environment Informatics Laboratory of the National Institute of Information and Communications Technology (NICT) is the regional warning center of International Space Environment Service in Japan. Japanese users mainly rely on NICT for the daily space weather forecasting [ Nagatsuma , 2013]. However, an accurate forecasting system has not yet been achieved. According to Akasofu [2007], the success of space weather prediction research lies on strong collaboration between solar, magnetospheric, interplanetary and upper atmospheric scientists. There is still much work to be done on this aspect. However, the education and training of potential researchers can build not only stronger collaborations, but also sustain data acquisition for a longer period of time, which is essential for solar-terrestrial research. Thus, in this paper, capacity building is proposed as a new tool for the advancement of space weather research.

Description: The Sun and its solar wind are currently exhibiting extremely low densities and magnetic field strengths, representing states that have never been observed during the space age. The highly abnormal solar activity between cycles 23 and 24 has caused the longest solar minimum in over 80 years and continues into the unusually small solar maximum of cycle 24. As a result of the remarkably weak solar activity, we have also observed the highest fluxes of galactic cosmic rays in the space age, and relatively small solar energetic particle events. We use observations from the Cosmic Ray Telescope for the Effects of Radiation (CRaTER) on the Lunar Reconnaissance Orbiter (LRO) to examine the implications of these highly unusual solar conditions for human space exploration. We show that while these conditions are not a show-stopper for long duration missions (e.g., to the Moon, an asteroid, or Mars), galactic cosmic ray radiation remains a significant and worsening factor that limits mission durations. While solar energetic particle events in cycle 24 present some hazard, the accumulated doses for astronauts behind 10 g/cm 2 shielding are well below current dose limits. Galactic cosmic radiation presents a more significant challenge: the time to 3% Risk of Exposure Induced Death (REID) in interplanetary space was less than 400 days for a 30 year old male and less than 300 days for a 30 year old female in the last cycle 23–24 minimum. The time to 3% REID is estimated to be ~20% lower in the coming cycle 24–25 minimum. If the heliospheric magnetic field continues to weaken over time, as is likely, then allowable mission durations will decrease correspondingly. Thus, we estimate exposures in extreme solar minimum conditions and the corresponding effects on allowable durations.

Description: Cover. In Figure 4 of Rastätter et al. [DOI: 10.1002/2014SW001083 ]: Current system contributions to Δ B . (a–c) The components of Δ B at the high-latitude station YKC, the midlatitude station OTT, and the low-latitude station FRD for Event 2. (d–f ) The perturbations at the same stations for Event 4. See pp. 553–565.

Description: The joint Taiwan-United States FORMOSAT-3/COSMIC (Constellation Observing System for Meteorology, Ionosphere, and Climate) mission, hereafter called COSMIC, is the first satellite constellation dedicated to remotely sense Earth's atmosphere and ionosphere using a technique called Global Positioning System (GPS) radio occultation (RO). The occultations yield abundant information about neutral atmospheric temperature and moisture as well as space weather estimates of slant total electron content, electron density profiles, and an amplitude scintillation index, S4. With the success of COSMIC, the United States and Taiwan are moving forward with a follow-on RO mission named FORMOSAT-7/COSMIC-2 (COSMIC-2), which will ultimately place 12 satellites in orbit with two launches in 2016 and 2019. COSMIC-2 satellites will carry an advanced Global Navigation Satellite System (GNSS) RO receiver that will track both GPS and Russian GLONASS signals, with capability for eventually tracking other GNSS signals from the Chinese BeiDou and European Galileo system, as well as secondary space weather payloads to measure low-latitude plasma drifts and scintillation at multiple frequencies. COSMIC-2 will provide 4-6 times (10-15× in the low latitudes) the number of atmospheric and ionospheric observations that were tracked with COSMIC, and will also improve the quality of the observations. In this article we focus on COSMIC/COSMIC-2 measurements of key ionospheric parameters.

Description: Key Points International workshop discussed SEP observations. Recommended that a set of guidelines be drafted for SEP cross-comparison. Recommended that the January 2014 SEP events be used for cross-comparisons.

Description: Whenever a significant intensity increase is being recorded by at least three neutron monitor stations in real-time mode, a ground level enhancement (GLE) event is marked and an automated alert is issued. Although, the physical concept of the algorithm is solid and has efficiently worked in a number of cases, the availability of real-time data is still an open issue and makes timely GLE alerts quite challenging. In this work we present the optimization of the GLE alert that has been set into operation since 2006 at the Athens Neutron Monitor Station. This upgrade has led to GLE Alert Plus , which is currently based upon the Neutron Monitor Database (NMDB). We have determined the critical values per station allowing us to issue reliable GLE alerts close to the initiation of the event while at the same time we keep the false alert rate at low levels. Furthermore, we have managed to treat the problem of data availability, introducing the Go-Back-N algorithm. A total of 13 GLE events have been marked from January 2000 to December 2012. GLE Alert Plus issued an alert for 12 events. These alert times are compared to the alert times of GOES SWPC and UMASEP. In all cases GLE Alert Plus precedes the GOES alert by ≈ 8-52 min. The comparison with UMASEP demonstrated a remarkably good agreement. Real-time GLE alerts by GLE Alert Plus may be retrieved by http://cosray.phys.uoa.gr/gle_alert_plus.html;http://www.nmdb.eu and http://swe.ssa.esa.int/web/guest/space-radiation . An automated GLE alert email notification system is also available to interested users.

Description: Solar Stormwatch was the first space weather citizen science project, the aim of which was to identify and track coronal mass ejections (CMEs) observed by the Heliospheric Imagers aboard the STEREO satellites. The project has now been running for approximately 4 years, with input from 〉16000 citizen scientists, resulting in a dataset of 〉38000 time-elongation profiles of CME trajectories, observed over 18 pre-selected position angles. We present our method for reducing this data set into aCME catalogue. The resulting catalogue consists of 144 CMEs over the period January-2007 to February-2010, of which 110 were observed by STEREO-A and 77 were observed by STEREO-B. For each CME, the time-elongation profiles generated by the citizen scientists are averaged into a consensus profile along each position angle that the event was tracked. We consider this catalogue to be unique, being at present the only citizen science generated CME catalogue, tracking CMEs over an elongation range of 4 degrees out to a maximum of approximately 70 degrees. Using single spacecraft fitting techniques, we estimate the speed, direction, solar source region and latitudinal width of each CME. This shows that, at present, the Solar Stormwatch catalogue (which covers only solar minimum years) contains almost exclusively slow CMEs, with a mean speed of approximately 350 kms −1 . The full catalogue is available for public access at www.met.reading.ac.uk/spate/stormwatch . This includes, for each event, the unprocessed time-elongation profiles generated by Solar Stormwatch, the consensus time-elongation profiles and a set of summary plots, as well as the estimated CME properties.

Description: Amateur radio reporting networks, such as the Reverse Beacon Network (RBN), PSKReporter, and the Weak Signal Propagation Network, are powerful tools for remote sensing the ionosphere. These voluntarily constructed and operated networks provide real-time and archival data that could be used for space weather operations, forecasting, and research. The potential exists for the study of both global and localized effects. The capability of one such network to detect space weather disturbances is demonstrated by examining the impacts on RBN-observed HF propagation paths of an X2.9 class solar flare detected by the GOES 15 satellite. Prior to the solar flare, the RBN observed strong HF propagation conditions between multiple continents, primarily Europe, North America, and South America. Immediately following the GOES 15 detection of the solar flare, the number of reported global RBN propagation paths dropped to less than 35% that of prior observations. After the flare, the RBN showed the gradual recovery of HF propagation conditions

Description: Key Points space weather radiation broadcast radiation environment Van Allen Probes mission

Description: Cover. In Zhang et al . [DOI: 10.1002/2014SW001079 ]: Longitude-averaged percent residuals from 15 day running mean GOCE densities at dusk for (top) April–May 2010 and (bottom) January–March 2012. The solid line indicates the latitude-averaged residuals, the red dots depict the residuals of the daily mean Kp from its 15 day running mean, and the black dotted curve is a 14.77 day sinusoidal oscillation, i.e., the lunar tide periodicity as seen from the GOCE orbit. The Kp residuals range between a minimum value of about −1.5 and a maximum value of about 2.4 in each panel. See pp. 538–551.

Description: Space weather impacts on communications are often presented as a raison d ’ etre for studying space weather ( e . g . Solar and Space Physics: A Science for a Technological Society, 2013.) Here we consider a communications outage during Operation Anaconda in Afghanistan that may have been related to ionospheric disturbances. Early military operations occurred during the peak of Solar Cycle 23 when ionospheric variability was enhanced. During Operation Anaconda, the Battle of Takur Ghar occurred at the summit of a 10,469-ft Afghan mountaintop on 4 March 2002 when the ionosphere was disturbed and could have affected UHF satellite communications. In this paper, we consider UHF SATCOM outages that occurred during repeated attempts to notify a Quick Reaction Force (QRF) on board an MH-47H Chinook to avoid a “hot” landing zone at the top of Takur Ghar. During a subsequent analysis of Operation Anaconda, these outages were attributed to poor performance of the UHF radios on the helicopters and to blockage by terrain. However, it is also possible that ionospheric anomalies together with multi-path effects could have combined to decrease the signal-to-noise ratio (SNR) of the communication links used by the QRF. A forensics study of Takur Ghar with data from the Global Ultraviolet Imager (GUVI) on the NASA Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) mission showed the presence of ionospheric bubbles (regions of depleted electron density) along the line of sight between the Chinook and the UHF communications satellites in geostationary orbit that could have impacted communications. The events of 4 March 2002 motivated us to develop the Mesoscale Ionospheric Simulation Testbed (MIST) model, which can be used to improve warnings of potential UHF outages during future military operations.

Description: We present the nowcast model for low energy (〈 200 keV) electrons in the inner magnetosphere which is the version of the Inner Magnetosphere Particle Transport and Acceleration Model (IMPTAM) for electrons. Low energy electron fluxes are very important to specify when hazardous satellite surface charging phenomena are considered. The presented model provides the low energy electron flux at all L-shells and at all satellite orbits, when necessary. The model is driven by the real time solar wind and Interplanetary Magnetic Field (IMF) parameters with 1 hour time shift for propagation to the Earth's magnetopause, and by the real time Dst index. Real time geostationary GOES 13 or GOES 15 (whenever each is available) data on electron fluxes in three energies, such as 40 keV, 75 keV, 150 keV, are used for comparison and validation of IMPTAM running online. On average, the model provides quite reasonable agreement with the data, the basic level of the observed fluxes is reproduced. The best agreement between the modeled and the observed fluxes are found for 〈 100 keV electrons. At the same time, not all the peaks and dropouts in the observed electron fluxes are reproduced. For 150 keV electrons, the modeled fluxes are often smaller than the observed ones by an order of magnitude. The Normalized Root-Mean-Square Deviation (NRMSD) is found to range from 0.015 to 0.0324. Though these metrics are buoyed by large standard deviations owing to the dynamic nature of the fluxes, they demonstrate that IMPTAM, on average, predicts the observed fluxes satisfactory. The computed binary event tables for predicting high flux values within each 1 hour window reveal reasonable hit rates being 0.660-0.318 for flux thresholds of 5 ⋅ 10 4 - 2 ⋅ 10 5 cm − 2 sec − 1 sr − 1 keV − 1 for 40 keV electrons, 0.739-0.367 for flux thresholds of 3 ⋅ 10 4 - 1 ⋅ 10 5 cm − 2 sec − 1 sr − 1 keV − 1 for 75 keV electrons, and 0.485-0.438 for flux thresholds of 3 ⋅ 10 3 - 3.5 ⋅ 10 3 cm − 2 sec − 1 sr − 1 keV − 1 for 150 keV electrons but rather small Heidke Skill Scores (0.17 and below). This is the first attempt to model low energy electrons in real time at 10 minutes resolution. The output of this model can serve as an input of electron seed population for real-time higher-energy radiation belt modeling.

Description: Between December 2010 and March 2013, volunteers for the Solar Stormwatch (SSW) Citizen Science project have identified and analysed Coronal Mass Ejections (CMEs) in the near real-time STEREO HI observations, in order to make “Fearless Forecasts” of CME arrival times and speeds at Earth. Of the 60 predictions of Earth-directed CMEs, 20 resulted in an identifiable ICME at Earth within 1.5-6 days, with an average error in predicted transit time of 22 h, and average transit time of 82.3 h. The average error in predicting arrival speed is 151 kms –1 , with an average arrival speed of 425 kms –1 . In the same time period, there were 44 CMEs for which there are no corresponding SSW predictions, and there were 600 days on which there was neither a CME predicted nor observed. A number of metrics show that the SSW predictions do have useful forecast skill, however there is still much room for improvement. We investigate potential improvements by using SSW inputs in three models of ICME propagation: two of constant acceleration and one of aerodynamic drag. We find that taking account of interplanetary acceleration can improve the average errors of transit time to 19 h and arrival speed to 77 kms –1 .

Description: Geomagnetically induced currents (GIC) are a space weather phenomenon that can interfere with power transmission and even cause blackouts. The primary drivers of GIC can be represented as ionospheric equivalent currents. We used IMAGE magnetometer data from 1994–2013 to analyze the extreme behavior of the time derivative of the equivalent current density (| Δ J eq |/ Δt ) together with the occurrence of modeled GIC in the European high-voltage power grids (1996–2008). Typically, when intense | Δ J eq |/ Δt occurred, geomagnetic activity extended to latitudes 〈 60 ∘ , Kp ≥ 8, and modeling suggested large GIC in the European high-voltage power grids. Intense, although short-lived, | ΔhbfJ eq |/ Δt also occurred when geomagnetic activity was confined to latitudes 〉 60 ∘ . In such cases, typically 5 ≤  Kp  〈 8, and modeling suggested that there were no large GIC in the European high-voltage power grids. Intense | Δ J eq |/ Δt and GIC occurred preferentially before midnight or at dawn and were rare after noon. There was a seasonal peak in October and a minimum around midsummer. Intense | Δ J eq |/ Δt and GIC occurred preferentially in the declining phase of the solar cycle and were rare around solar minima. A longer perspective (1975–2013) was obtained by comparison with the time derivative of the magnetic field from the IMAGE station Nurmijärvi (NUR, MLAT ∼ 57 ∘ ). NUR data indicated that the quietness of summer months may have been due to a coincidental lack of intense storms during the shorter period. NUR data agreed with the increased activity in the declining phase, but demonstrated that extreme events could also occur during solar minima.

Description: Our study statistically compares the total energy flux outputs of Newell et al.’s 2010 OVATION Prime model, Hardy et al.’s 1991 Kp-based model, and a coupled Space Weather Modeling Framework-Ring Current model to energy flux data obtained from 2,198 Defense Meteorological Satellite Program (DMSP) satellite passes in the northern hemisphere. Our DMSP dataset includes 28 days grouped into continuous 3- and 4-day periods between 2000 and 2008 and encompasses magnetic local times (MLT) between 0400 and 2100. We obtain the most equatorward magnetic latitude (MLAT) coordinate where a DMSP satellite energy flux measurement exceeds 0.4 erg/cm 2 /s and use this point as a proxy for the equatorward boundary of the auroral oval in a particular MLT sector. We then calculate a prediction efficiency (PE) score by comparing the DMSP boundary coordinates to each model, using the same energy flux threshold to obtain a model's boundary location. We find the PE for the OVATION Prime model is 0.55 and the PE for the Hardy Kp model is 0.51. When we accomplish the same analysis using a higher energy flux threshold equal to 0.6 erg/cm 2 /s, the OVATION Prime model's PE increases to 0.58, while the Hardy Kp model's score drops to 0.41. Our results indicate more complex modeling techniques, like those used in OVATION Prime, can more accurately model the auroral oval's equatorward boundary. However, Hardy's discretized Kp model, despite its relative simplicity, is still a competitive and viable modeling option.

Description: Relationships exist between radiation belt electron flux intensities and solar drivers such as solar wind speed, ion density, and magnetic fields. The particulars of these relationships, however, are not well understood. Many forecasting models have been developed in the last 25 years, attempting to make sense of these relationships and produce accurate forecasts for electron flux intensities. We discuss some of the inherent limitations that many forecasting models (e.g., static models) possess when trying to untangle the intricate and dynamic relationships between electron flux levels and solar wind drivers. Dynamics related to the solar cycle limit physical interpretations for static forecasting models to customized and narrow time windows. Furthermore, the interrelatedness of solar drivers severely limit the ability to uniquely partition and describe the relationship between any one solar driver with electron flux levels. We suggest an alternate approach using dynamic linear models (DLMs). DLMs avoid some of the inherent limitations of physical understanding static models possess. We compare the one-day-ahead forecast accuracy of a relatively simple DLM to the current NOAA relativistic electron forecast model (REFM). The REFM does produce a more favorable prediction efficiency averaged across years when compared to the relatively simple DLM (.749 to .721). However, the competitiveness of the DLM suggests that further development may lead to more accurate and interpretable models in the future.

Description: Using data of GPS receivers located worldwide, we analyze the quality of GPS performance during four geomagnetic storms of different intensity: two super-storms and two intense storms. We show that during super-storms the density of GPS Losses-of-Lock (LoL) increases up to 0.25% at L1-frequency and up to 3% at L2-frequency, and up to 0.15% (at L1) and 1% (at L2) during less intense storms. Also, depending on the intensity of the storm-time ionospheric disturbances, the total number of TEC-slips can exceed from 4 to 40 times the quiet-time level. Both GPS LoL and TEC-slips occur during abrupt changes of SYM-H index of geomagnetic activity, i.e. during the main phase of geomagnetic storms and during development of ionospheric storms. The main contribution in the total number of GPS LoL was found to be done by GPS sites located at low- and high-latitudes, whereas the area of numerous TEC-slips seemed to mostly correspond to the boundary of the auroral oval, i.e. region with intensive ionospheric irregularities. Our global maps of TEC-slips show where the regions with intense irregularities of electron density occur during geomagnetic storms and will let us in future predict appearance of GPS errors for geomagnetically disturbed conditions.

Description: [1]  Thermospheric density impacts satellite position and lifetime through atmospheric drag. More accurate specification of thermospheric temperature, a key input to current models such as the High Accuracy Satellite Drag Model (HASDM), can decrease model density errors. This paper improves the model of Burke et al. (2009) to model thermospheric temperatures using the magnetospheric convective electric field as a driver. In better alignment with Air Force satellite tracking operations, we model the arithmetic mean temperature, T 1/2 , defined by the Jacchia (1977) model as the mean of the daytime maximum and nighttime minimum exospheric temperatures occurring in opposite hemispheres at a given time, instead of the exospheric temperature used by Burke et al. (2009). Two methods of treating the solar ultraviolet (UV) contribution to T 1/2 are tested. Two model parameters, the coupling and relaxation constants, are optimized for 38 storms from 2002 - 2008. Observed T 1/2 values are derived from densities and heights measured by the Gravity Recovery and Climate Experiment (GRACE) satellite. The coupling and relaxation constants were found to vary over the solar cycle and are fit as functions of F 10.7a , the 162-day average of the F 10.7 index. Model results show that allowing temporal UV variation decreased model T 1/2 errors for storms with decreasing UV over the storm period but increased T 1/2 errors for storms with increasing UV. Model accuracy was found to be improved by separating storms by type (Coronal Mass Ejection or Co-rotating Interaction Region). The model parameter fits established will be useful for improving satellite drag forecasts.

Description: Key Points Obituary for Robert D. Hunsucker 1930-2014

Description: The comment is about the general context, namely concerns regarding exposure hazards due to ionizing radiation during air travel. Implicitly, the authors assume what is called linear no-threshold (LNT) model of radiation-induced negative health effects. With the LNT model, it is assumed that each ionizing radiation dose increment, no matter how small, constitutes an increase in the cancer risk to humans. However, the scientific validity of this model has never been proven and has been seriously questioned and debated for many decades. Particularly regarding air travel, epidemiological studies of flight crew have failed to show a consistent increase in cancer risk. On the opposite side of the debate, numerous studies (experimental, epidemiological, and ecological) have shown that low doses of ionizing radiation can be beneficial to health. The above considerations are totally ignored by the referenced article, which, unfortunately, implicitly promotes radiophobia - an irrational fear of radiation hazards. We strongly recommend that papers dealing - though implicitly - with low-dose-radiation health risks, would contain critical scientific review of these risks.

Description: Cover. Joyce et al. doi: 10.1002/2013SW000997 provided a plot of computed dose and dose equivalent rates for varying altitudes in the Earth and Mars atmospheres. Each curve is well described by a third order polynomial fit. The functional forms are provided to enable future studies to easily estimate atmospheric dose rates during times when CRaTER data is unavailable using measurements or estimations of the dose rate at 1AU through a similar level of shielding.

Description: Ionospheric irregularities are a regular occurrence at the equatorial latitude during the post sunset hours especially during high solar activity. These irregularities could pose serious challenges to satellite-based navigation and positioning applications by causing fading and degradation of trans-ionospheric signals passing through these irregularities. We have investigated large-scale ionospheric irregularities occurrence at Ilorin, Nigeria (Lat. = 8.48 °N, Long. = 4.67 °W, Dip = 4.1 °S), a station located within the equatorial region in the African sector. The index used in this study is the rate of change of TEC (ROT) derived from 30 seconds RINEX data obtained using a dual frequency GPS receiver (i.e. NovAtel GPStation-2). The study covers a period of four years (2009 to 2012). The results obtained showed that large-scale irregularities occur between March and November and are more pronounced between 1900 LT and 2400 LT. The irregularities were observed to show two peaks; one in March and the other in September. Solar activity trend was also observed. The irregularities level around the peaks seems to increase with solar activity. Although the study covered a period of four years, the period could be regarded as the increasing phase of the solar cycle 24.

Description: The prognosis of four cancer deaths among air passengers potentially incurred from a solar radiation storm during Sep. 30 – Oct. 1, 2013 rests on a procedure which the International Commission on Radiological Protection considers invalid. It rather resembles an exercise in numerology, i.e., “ a study of the purported divine, mystical or other special relationship between a number and some coinciding observed (or perceived) events ”.

Description: The premise of this comment perpetuates an unfortunate trend among some radiation researchers to minimize potential risks to human tissue from low radiation sources. In fact, this discussion on the risk uncertainties of low dose radiation further illustrates the need for more measurements and a program of active monitoring, especially when solar eruptive events can substantially elevate the radiation environment. This debate also highlights the context of a bigger problem, i.e., how do we as professionals act with due diligence to take the immense body of knowledge of space weather radiation effects on human tissue and distill it into ideas that regulatory agencies can use to maximize the safety of a population at risk. The focus of our article on radiation risks due to solar energetic particle events starts with our best assessment of risks and is based on the body of scientific knowledge while, at the same time, erring on the side of public safety. The uncertainty inherent in our assessment is accepted and described with this same philosophy in mind.

Description: Space weather forecasting critically depends upon availability of timely and reliable observational data. It is therefore particularly important to understand how existing and newly planned observational assets perform during periods of severe space weather. Extreme space weather creates challenging conditions under which instrumentation and spacecraft may be impeded or in which parameters reach values that are outside the nominal observational range. This paper analyzes existing and upcoming observational capabilities for forecasting, and discusses how the findings may impact space weather research and its transition to operations. A single limitation to the assessment is lack of information provided to us on radiation monitor performance, which caused us not to fully assess (i.e., not assess short-term) radiation storm forecasting. The assessment finds that at least two widely spaced coronagraphs including L4 would provide reliability for Earth-bound CMEs. Furthermore, all magnetic field measurements assessed fully meet requirements. However, with current or even with near term new assets in place, in the worst-case scenario there could be a near-complete lack of key near-real-time solar wind plasma data of severe disturbances heading toward and impacting Earth's magnetosphere. Models that attempt to simulate the effects of these disturbances in near real time or with archival data require solar-wind plasma observations as input. Moreover, the study finds that near-future observational assets will be less capable of advancing the understanding of extreme geomagnetic disturbances at Earth, which might make the resulting space weather models unsuitable for transition to operations.

Description: We examine thermospheric neutral density response to 172 solar wind high-speed streams (HSSs) and the associated stream interfaces during the equinox seasons of 2002–2008. HSSs produce prolonged enhancements in satellite drag. We find responses to two drivers: 1) the equinoctial Russell-McPherron (R-M) effect, which allows the azimuthal component of the interplanetary magnetic field (IMF) to project onto Earth's vertical dipole component; and 2) coronal streamer structures, which are extensions of the Sun's meso-scale magnetic field into space. Events for which the IMF projection is antiparallel to the dipole field are classified as “Effective-E”, otherwise they are “Ineffective-I”. Effective orientations enhance energy deposition and subsequently thermospheric density variations. The IMF polarities preceding and following stream interfaces at Earth produce events that are: Effective-Effective-EE; Ineffective-Ineffective-II; Ineffective-Effective-IE; and Effective-Ineffective-EI. These categories are additionally organized according to their coronal source structure: helmet streamers (HS-EI and HS-IE) and pseudo-streamers (PS-EE and PS-II). Approximately 65% of these combinations are HS-EI or HS-IE. The response to HS-IE structures is smoothly varying and long-lived, while the response to PS-EE structures is erratic, short-lived, and modulated by thermospheric preconditioning. We find significant distinguishable responses to these drivers in four geomagnetically sensitive observations: low-energy particle precipitation, proxied Joule heating, nitric oxide flux, and neutral density. Distinct signatures exist in neutral density response that can be anticipated days in advance based on currently available knowledge of on-disk coronal holes. Further, we show that the HS-IE events produce the largest neutral density disturbances, with δ ρ max,IE exceeding δ ρ max,EI by more than 30%.

Description: Key Points NOAA Scientist Recognized World Data Service (WDS) recognizes early career scientist WDS operates under the auspices of the International Council for Science

Description: Cover. In Newell et al. [DOI: 10.1002/2014SW001056 ]: The energy flux predicted for mean solar wind driving ( d Ф MP / dt =4.3 × 105 Wb/s) summed over the four auroral types in (top) OP-2010, (bottom) OP-2013. Note the reduction in salt and pepper noise, and the smoother interpolation across the premidnight region of low data. See pp. 368–379.

Description: ABSTRACT The Earth's ionosphere is a highly dynamic region that is almost constantly in a state of flux. Solar radiation, geomagnetic activity, chemical reactions, and natural dynamics all act to perturb the state of the ionosphere. The ionosphere changes on time scales of hours to days, with the fine-scale ionospheric structures that are frequently observed lacking in global physics-based models due to time-step and spatial resolution constraints. To properly specify the ionosphere, data is needed, thus data assimilation. The Utah State University GAIM-GM model uses a data assimilation method to correct a physics-based model of the ionosphere using 5 different data types, divided into 9 different data sources. Multiple data types are necessary because the data from any individual data source will not be sufficient for global reconstructions. The GAIM-GM specification (in real-time) can then be used to correct for ionospheric propagation delays, thereby improving geo-location and communications. The focus here is to show the quantitative effects that multiple data types have on GAIM-GM ionospheric specifications for a relatively quiet day (April 19) in 2012.

Description: Key Points Satellite operators acknowledge the value of a anomaly database Satellite operators are reluctant to release sensitive technical data Techniques are available to safeguard information in a centralized database

Description: Cover. In Zhao and Dryer [DOI: 10.1002/2014SW001060 ]: Solar wind conditions to 2 AU in the ecliptic plane predicted by HAFv.2 for the 23 Dec 1998 flare/Type II-shock event. Upper left: interplanetary magnetic field (IMF) pattern; Upper right: solar wind velocity; Lower left: proton density with IMF pattern; Lower right: predicted dynamic pressure. Adopted from Fry et al . [2003]. See pp. 448–469.

Description: In 2010, the Department of Homeland Security's Federal Emergency Management Agency (FEMA) partnered with the National Oceanic and Atmospheric Administration's Space Weather Prediction Center (SWPC) to investigate the potential for extreme space weather conditions to impact National Security/Emergency Preparedness communications—those communications vital to a functioning government and to emergency and disaster response—in the United States. Given the interdependencies of modern critical infrastructure, the initial meta-analysis of academic research on space weather effects on communications expanded to other critical infrastructure sectors, federal agencies, and private sector organizations. While the effort is ongoing, and despite uncertainties inherent with this hazard, FEMA and the SWPC did draw some conclusions. If electric power remains available, an extreme space weather event will result in the intermittent loss of HF and similar sky wave radio systems, minimal direct impact to public safety line-of-sight radio and commercial cellular services, a relatively small loss of satellite services as a percentage of the total satellite fleet, interference or intermittent loss of satellite communications and GPS navigation and timing signals, and no first-order impact to consumer electronic devices. Vulnerability of electric power to an extreme geomagnetic storm remains the primary concern from an emergency management perspective but actual impact is not well understood at present. A discussion of potential impacts to infrastructure from the loss of electric power from any hazard is provided using the 2011 record tornado outbreak in Alabama as an example.

Description: As the utilization of low-earth orbit (LEO) increases, so does the need for improved ephemeris predictions and thus more accurate density models. In this paper we quantify the density variability of the thermosphere attributable to the lunar gravitational tide, a potentially predictable component of variability not included in any operational density prediction models to date. Using accelerometer measurements from the GOCE satellite near 260 km altitude, the level of lunar tidal density variability is shown to be about half that associated with the low level of geomagnetic variability that occurs about 75% of the time (Kp ≤ 3), thus constituting an element of “space weather”. Our conclusion is that the lunar tide ought to be considered for inclusion in contemporary density models of the thermosphere for operational ephemeris predictions. Some suggested first steps are included in the conclusions of this paper.

Description: Recent papers have linked the heliospheric magnetic flux to the sunspot cycle with good correlation observed between prediction and observation. Other papers have shown a strong correlation between magnetic flux and solar wind proton flux from coronal holes. We combine these efforts with an expectation that the sunspot activity of the approaching solar minimum will resemble the Dalton or Gleissberg Minimum and predict that the magnetic flux and solar wind proton flux over the coming decade will be lower than at any time during the space age. Using these predictions and established theory we also predict record high galactic cosmic ray intensities over the same years. The analysis shown here is a prediction of global space climate change within which space weather operates. It predicts a new parameter regime for the transient space weather behavior that can be expected during the coming decade.

Description: Cover. In Oladipo et al. [DOI: 10.1002/2013SW000991 ]: Ionospheric irregularities occurrence at Ilorin, Nigeria for 2009–2012. The ROTI AVE index value in TECU/min is indicated in color code. The white space in each plot indicates data gap. See pp. 300–305.

Description: An algorithm has been developed for specifying 〉 2  MeV electron flux everywhere along geosynchronous orbit for use in operational products. The statistics of integrated electron fluxes from four GOES satellites for more than a solar cycle clearly indicate that the local time variation can be represented by a Gaussian distribution as a function of geomagnetic Kp index, which empirically determines the center and the half width of the Gaussian distribution. Using the most current estimated three-hour Kp value as an input, the prediction scheme requires the most recent electron flux measurements from available GOES satellite(s) to determine the maximum and minimum for a Gaussian fit and to provide estimated electron fluxes at geosynchronous orbit with the time resolution of the instrument. In balancing between sufficient data for statistics and the change of geomagnetic configuration, the optimal length of data accumulation time for nowcasting is 6 hours when one or two satellites are available. The prediction efficiency ( PE ) is independent of local time and solar cycle. We found that the PE values are greater than 0.5 when Kp  〈 5 and independent of Kp at low and moderate values; however, PE decreases dramatically with increasing Kp when Kp ≥5. Although the PE varies from year-to-year and with the choice of the test satellite, our finding resulted in a PE  〉 0.6 in 67.6% of the cases and PE  〉 0.8 more than 23.5% of the time based on our analysis from four GOES satellites between 1998 and 2009. Moreover, skill scores from our newly developed algorithm are ~90% of the time better than those resulting from a simpler algorithm based on a table provided by O'Brien (2009), indicating a dramatic improvement in predictive capability.

Description: Ionospheric scintillation refers to amplitude and phase fluctuations in radio signals due to electron density irregularities associated to structures named ionospheric plasma bubbles. The phenomenon is more pronounced around the magnetic equator where, after sunset, plasma bubbles of varying sizes and density depletions are generated by plasma instability mechanisms. The bubble depletions are aligned along Earth's magnetic field lines, and they develop vertically upward over the magnetic equator so that their extremities extend in latitude to north and south of the dip equator. Over Brazil, developing bubbles can extend to the southern peak of the Equatorial Ionization Anomaly, where high levels of ionospheric scintillation are common. Scintillation may seriously affect satellite navigation systems, such as the Global Navigation Satellite Systems. However, its effects may be mitigated by using a predictive model derived from a collection of extended databases on scintillation and its associated variables. This work proposes the use of a classification and regression decision tree to perform a study on the correlation between the occurrence of scintillation at the magnetic equator and that at the southern peak of the equatorial anomaly. Due to limited size of the original database, a novel resampling heuristic was applied to generate new training instances from the original ones in order to improve the accuracy of the decision tree. The correlation analysis presented in this work may serve as a starting point for the eventual development of a predictive model suitable for operational use.

Description: Solar energetic particles (SEPs) sometimes induce powerful air showers that significantly increase the radiation dose at flight altitudes. In order to provide information of such a space radiation hazard to aircrew, a forecast model is developed for WASAVIES (Warning System of Aviation Exposure to SEP), based on the focused transport equation of solar protons and Monte Carlo particle transport simulation of the air shower. WASAVIES gives a simple and fast way to predict the time profile of dose rate during ground-level enhancements (GLEs).

Description: The high-energy protons trapped in the inner Van Allen belt are a hazard to the man-made space systems orbiting the region. We analyze the possibility of human control over these energetic particles by the transmission of electromagnetic ion cyclotron (EMIC) waves from space-based antennas. We examine the propagation of man-made EMIC waves, their interaction with the energetic inner belt proton population, and the overall feasibility of controlled proton precipitation. The nature of the interaction between EMIC waves radiated from space-based transmitters and energetic protons is different from the naturally occurring processes in the magnetosphere, the latter being dominated by gyroaveraged resonant interactions. In the case of man-made EMIC waves, we show that off-resonant interactions dominate the particles’ scattering. However, our numerical simulations show that both the radiation and interaction processes are very inefficient, to the point that, with the current technology, it is not feasible to remediate the proton belt using space-based transmitters.

Description: Since energetic protons (∼100 keV) hinder space-based X-ray imaging, there is a need to characterize the proton environments encountered by a soft X-ray mission when planning missions and operations in the near-Earth environment. Impacts range from enhanced noise in the images to damage to CCD detectors. The high-apogee (17.9 R E ) inclined (40 ∘ ) and elliptical orbit of ESA's XMM-Newton mission frequently passes through the Earth's Van Allen radiation belts on closed magnetosphericmagnetic field lines, the magnetotail lobes on open magnetic field lines, and into the magnetosheath and solar wind on open solar magnetic field lines, four regions with very different energetic proton environments. We use XMM-Newton measurements from 2000 to 2010 to survey the occurrence of proton strikes or “soft proton flares” on the EPIC PN CCD detector. Proton flares affect ∼ 55 % of all measurements. Rates vary from 50% at large radial distances in the solar wind and magnetosheath, to 25% in the high-latitude magnetotail lobes, and increase to 66% of the measurements on closed low-latitude magnetospheric magnetic field lines.

Description: Advanced forecasting of space weather requires simulation of the whole Sun-to-Earth system, which necessitates driving magnetospheric models with the outputs from solar wind models. This presents a fundamental difficulty, as the magnetosphere is sensitive to both large-scale solar wind structures, which can be captured by solar wind models, and small-scale solar wind “noise,” which is far below typical solar wind model resolution and results primarily from stochastic processes. Following similar approaches in terrestrial climate modelling, we propose statistical “downscaling” of solar wind model results prior to their use as input to a magnetospheric model. As magnetospheric response can be highly nonlinear, this is preferable to downscaling the results of magnetospheric modelling. To demonstrate the benefit of this approach, we first approximate solar wind model output by smoothing solar wind observations with an 8-hour filter, then add small-scale structure back in through the addition of random noise with the observed spectral characteristics. Here we use a very simple parameterisation of noise based upon the observed probability distribution functions of solar wind parameters, but more sophisticated methods will be developed in the future. An ensemble of results from the simple downscaling scheme are tested using a model-independent method and shown to add value to the magnetospheric forecast, both improving the best-estimate and quantifying the uncertainty. We suggest a number of features desirable in an operational solar wind downscaling scheme.

Description: OVATION Prime (OP) is an auroral precipitation model parameterized by solar wind driving. Distinguishing features of the model include an optimized solar wind-magnetosphere coupling function ( d Φ MP / dt ) which predicts auroral power significantly better than Kp or other traditional parameters, the separation of aurora into categories (diffuse aurora, monoenergetic, broadband, and ion), the inclusion of seasonal variations, and separate parameter fits for each MLAT x MLT bin, thus permitting each type of aurora and each location to have differing responses to season and solar wind input – as indeed they do. We here introduce OVATION Prime-2013, an upgrade to the 2010 version currently widely available. The most notable advantage of OP-2013 is that it uses UV images from the GUVI instrument on the satellite TIMED for high disturbance levels ( d Φ MP / dt  〉 1.2 MWb/s which roughly corresponds to Kp  = 5+ or 6-). The range of validity is approximately 0 〈  d Φ MP / dt  ≤ 3.0 MWb/s ( Kp about 8+). Other upgrades include a reduced susceptibility to salt and pepper noise, and smoother interpolation across the postmidnight data gap. The model is tested against an independent data set of hemispheric auroral power from Polar UVI. Over the common range of validity of OP-2010 and OP-2013 the two models predict auroral power essentially identically, primarily because hemispheric power calculations were done in a way to minimize the impact of OP-2010s noise. To quantitatively demonstrate the improvement at high disturbance levels would require multiple very large substorms, which are rare, and insufficiently present in the limited data set of Polar UVI hemispheric power values. Nonetheless, although OP-2010 breaks down in a variety of ways above Kp = 5+ or 6-, OP-2013 continues to show the auroral oval advancing equatorward, at least to 55 o MLAT or a bit less, and OP-2013 does not develop spurious large noise patches. We will also discuss the advantages and disadvantages of other precipitation models more generally, as no one model fits best all possible uses.

Description: The near-Earth space environment is strongly driven by the solar wind and interplanetary magnetic field. This study presents a model for predicting the solar wind speed up to five days in advance. Probability Distribution Functions (PDFs) were created that relate the current solar-wind speed and slope to the future solar-wind speed, as well as the solar-wind speed to the solar-wind speed one solar rotation in the future. It was found that a major limitation of this type of technique is that the solar-wind periodicity is close to 27 days but can be from about 22 to 32 days. Further, the optimum lag between two solar rotations can change from day to day, making a prediction of the future solar-wind speed based solely on the solar-wind speed approximately 27 days ago quite difficult. It was found that using a linear combination of the solar-wind speed one solar rotation ago and a prediction of the solar-wind speed based on the current speed and slope is optimal. The linear weights change as a function of the prediction horizon, with shorter prediction times putting more weight on the prediction based on the current solar-wind speed and the longer prediction times based on an even spread between the two. For all prediction horizons from 8 hours up to 120 hours, the PDF model is shown to be better than using the current solar wind speed (i.e., persistence), and better than the Wang-Sheeley-Arge Model for prediction horizons of 24 hours.

Description: The Cosmic Ray Telescope for the Effects of Radiation (CRATER), an instrument carried on the Lunar Reconnaissance Orbiter (LRO) spacecraft, directly measures the energy depositions by solar and galactic cosmic radiations in its silicon wafer detectors. These energy depositions are converted to linear energy transfer (LET) spectra. High LET particles, which are mainly high energy heavy ions found in the incident cosmic ray spectrum, or target fragments and recoils produced by protons and heavier ions, are of particular importance because of their potential to cause significant damage to human tissue and electronic components. Aside from providing LET data useful for space radiation risk analyses for lunar missions, the observed LET spectra can also be used to help validate space radiation transport codes, used for shielding design and risk assessment applications, which is a major thrust of this work. In this work the Monte Carlo transport code HETC-HEDS (High Energy Transport Code – Human Exploration and Development in Space) is used to estimate LET contributions from the incident primary ions and their charged secondaries produced by nuclear collisions as they pass through the three pairs of silicon detectors. Also in this work, the contributions to the LET of the primary ions and their charged secondaries are analyzed and compared with estimates obtained using the deterministic space radiation code HZETRN2010, developed at NASA Langley Research Center. LET estimates obtained from the two transport codes are compared with measurements of LET from the CRaTER instrument during the mission. Overall, a comparison of the LET predictions of the HETC-HEDS code to the predictions of the HZETRN code displays good agreement. The code predictions are also in good agreement with the CRaTER LET measurements above 15 keV/micron, but differ from the measurements for smaller values of LET. A possible reason for this disagreement between measured and calculated spectra below 15 keV/micron is an inadequate representation of the light ion spectra in HETC-HEDS and HZETRN code calculations. It is also clear from the results of this work that Vavilov distributions need to be incorporated into the HETC-HJEDS code before it will be able to recreate the observed LET spectra measured by the CRaTER instrument.

Description: MAG4 is a technique of forecasting an active region's rate of production of major flares in the coming few days from a free-magnetic-energy proxy. We present a statistical method of measuring the difference in performance between MAG4 and comparable alternative techniques that forecast an active region's major-flare productivity from alternative observed aspects of the active region. We demonstrate the method by measuring the difference in performance between the “Present MAG4” technique and each of three alternative techniques, called “McIntosh Active-Region Class,” “Total Magnetic Flux,” and “Next MAG4.” We do this by using (1) the MAG4 database of magnetograms and major-flare histories of sunspot active regions, (2) the NOAA table of the major-flare productivity of each of 60 McIntosh active-region classes of sunspot active regions, and (3) five technique-performance metrics (Heidke Skill Score, True Skill Score, Percent Correct, Probability of Detection, and False Alarm Rate) evaluated from 2000 random two-by-two contingency tables obtained from the databases. We find that (1) Present MAG4 far outperforms both McIntosh Active-Region Class and Total Magnetic Flux, (2) Next MAG4 significantly outperforms Present MAG4, (3) the performance of Next MAG4 is insensitive to the forward and backward temporal windows used, in the range of one to a few days, and (4) forecasting from the free-energy proxy in combination with either any broad category of McIntosh active-region classes or any Mount Wilson active-region class gives no significant performance improvement over forecasting from the free-energy proxy alone (Present MAG4).

Description: One of the major solar transients, coronal mass ejections (CMEs) and their related interplanetary shocks have severe space weather effects and become the focus of study for both solar and space scientists. Predicting their evolutions in the heliosphere and arrival times at Earth is an important component of the space weather predictions. Various kinds of models in this aspect have been developed during the past decades. In this paper, we will present a view of the present status (during Solar Cycle 24 in 2014) of the space weather's objective to predict the arrival of coronal mass ejections and their interplanetary shock waves at Earth. This status, by implication, is relevant to their arrival elsewhere in the solar system. Application of this prediction status is clearly appropriate for operational magnetospheric and ionospheric situations including A -〉 B -〉 C…solar system missions. We review current empirical models, expansion speed model, drag-based models, physics-based models (and their real-time prediction's statistical experience in Solar Cycle 23) and MHD models. New observations in Solar Cycle 24, including techniques/models, are introduced as they could be incorporated to form new prediction models. The limitations of the present models and the direction of further development are also suggested.

Description: Geomagnetically induced currents are known to induce disturbances in the electric power grid. Here, we perform a statistical analysis of 11,242 insurance claims from 2000 through 2010 for equipment losses and related business interruptions in North-American commercial organizations that are associated with damage to, or malfunction of, electrical and electronic equipment. We find that claims rates are elevated on days with elevated geomagnetic activity by approximately 20% for the top 5%, and by about 10% for the top third of most active days ranked by daily maximum variability of the geomagnetic field. When focusing on the claims explicitly attributed to electrical surges (amounting to more than half the total sample), we find that the dependence of claims rates on geomagnetic activity mirrors that of major disturbances in the U.S. high-voltage electric power grid. The claims statistics thus reveal that large-scale geomagnetic variability couples into the low-voltage power distribution network and that related power-quality variations can cause malfunctions and failures in electrical and electronic devices that, in turn, lead to an estimated 500 claims per average year within North America. We discuss the possible magnitude of the full economic impact associated with quality variations in electrical power associated with space weather.

Description: Described here is the development of a new project, the Coronal-Solar Wind Energetic Particle Acceleration (C-SWEPA) Modules, which couples the CORHEL MHD models within the low corona with EMMREM for characterizing energetic particle acceleration and subsequent formation of energetic particle hazards. We have shown initial results of the coupling, in which an extreme SEP event with a broad longitudinal extent was formed from a fast CME at 2-5 solar radii. This model showed large enough differential energy fluxes to approach 30-Day radiation limits even behind thick spacecraft shielding (10 g/cm2). The fact that the event was so abrupt, with high-energy fluxes formed within only 2 hours after CME onset, demonstrates the significant potential hazard for astronauts and spacecraft. The development of accurate predictive models, response strategies, and an understanding of the statistical probability for this type of prompt and extreme SEP event is the focus of C-SWEPA research in the NASA/NSF Space Weather Modeling Collaborative (Schunk, 2014).

Description: The Rice neural network models of Kp have been running in realtime at http://mms.rice.edu/realtime/forecast.html since October 2007; Dst and AE models were added to our operations in May 2010. All these models use the Boyle index as basis functions computed from ACE realtime inputs. Later, two more driving functions were included in November 2012: a) the “Ram" functions that had dynamic pressure term added to the Boyle index, and b) the Newell functions. The Wing models are a set of neural network-based Kp forecast models adopted by NOAA/SWPC in March 2011 to supersede the Costello Kp model. This study indicates that any of the three Rice neural net predictors had a better success rate than the Wing model in predicting Kp (r = 0.828 with Boyle, r = 0.843 with Ram and r = 0.820 with Newell for 1 hour predictions; similarly r = 0.739, 0.769 and 0.755 for 3 hour predictions) in real time. In a head-to-head challenge using harvested realtime outputs between April 2011 and February 2013, the Rice Boyle Kp models predicted better than the Wing models (0.771 vs 0.714 for 1 hour predictions and 0.770 vs 0.744 for 3 hour predictions). In addition, Wing's prediction was missing more often than the Rice prediction (≈6% versus 4.6%), meaning it had less reliability. The Rice models also predict AE (r = 0.811 with Boyle; 0.806 with Ram; 0.765 with Newell and 0.743 with Boyle; 0.747 with Ram for 1- and 3-hour predictions) and pressure-corrected Dst (r = 0.790; 0.767 and 0.704 and r = 0.795; 0.797 and 0.707 for 1- and 3-hour predictions).

Description: Cover. In Newell et al. [DOI: 10.1002/2014SW001056 ]: The energy flux predicted for mean solar wind driving ( d Ф MP / dt =4.3 × 105 Wb/s) summed over the four auroral types in (top) OP-2010, (bottom) OP-2013. Note the reduction in salt and pepper noise, and the smoother interpolation across the premidnight region of low data. See pp. 368–379.

Description: [1]  We expand upon the efforts of Joyce et al. (2013) who computed the modulation potential at the Moon using measurements from the Cosmic Ray Telescope for the Effects of Radiation (CRaTER) instrument on the Lunar Reconnaissance Orbiter (LRO) spacecraft along with data products from the Earth-Moon-Mars Radiation Environment Module (EMMREM). Using the computed modulation potential, we calculate galactic cosmic ray (GCR) dose and dose equivalent rates in the Earth and Mars atmospheres for various altitudes over the course of the LRO mission. While we cannot validate these predictions by directly comparable measurement, we find that our results conform to expectations and are in good agreement with the nearest available measurements and therefore may be used as reasonable estimates for use in efforts in risk assessment in the planning of future space missions as well as in the study of GCRs. PREDICCS (Predictions of radiation from REleASE, EMMREM, and Data Incorporating the CRaTER, COSTEP and other SEP measurements) is an online system designed to provide the scientific community with a comprehensive resource on the radiation environments of the inner heliosphere. The data products shown here will be incorporated into PREDICCS in order to further this effort and daily updates will be made available on the PREDICCS website ( http://prediccs.sr.unh.edu ).

Description: [1]  Slant Total Electron Content (STEC), the total number of free electrons on a ray path, is an important space weather observable. STEC is the main input for Computerized Ionospheric Tomography (CIT). STEC can be estimated using the dual-frequency GPS receivers. GPS-STEC contains the space weather variability, yet the estimates are prone to measurement and instrument errors that are not related to the physical structure of the ionosphere. International Reference Ionosphere Extended to Plasmasphere (IRI-Plas) is the international standard climatic model of ionosphere and plasmasphere, providing vertical electron density profiles for a desired date, time and location. IRI-Plas is used as the background model in CIT. Computation of STEC from IRI-Plas is a tedious task for researchers due to extensive geodetic calculations and IRI-Plas runs. In this study, IONOLAB group introduces a new space weather service to facilitate the computation of STEC from IRI-Plas (IRI-Plas-STEC) at www.ionolab.org . The IRI-Plas-STEC can be computed online for a desired location, date, hour, elevation and azimuth angle. The user-friendly interface also provides means for computation of IRI-STEC for a desired location and date to indicate the variability in hour of the day, elevation or azimuth angles. The desired location can be chosen as a GPS receiver in IGS or EUREF networks. Also instead of specifying elevation and azimuth angles, the user can directly choose from the GPS satellites and obtain IRI-Plas-STEC for a desired date and/or hour. The computed IRI-Plas-STEC values are presented directly on the screen or via email as both text and plots.

Description: [1]  An intense solar radio burst occurred on 24 September 2011, which affected the tracking of Global Navigation Satellite System (GNSS) signals by receivers located in the sunlit hemisphere of the Earth. This manuscript presents for the first time the impacts of this radio burst on the availability of Fugro's real-time precise point positioning service for GNSS receivers and on the quality of the L-band data link used to broadcast this service. During the peak of the radio burst (12:50-13:20 UT), a reduction in the L-band signal to noise ratio (SNR) is observed. For some receiver locations, a reset in the position filter is observed, which can be either due to the reduction in the L-band SNR or the reduction in the number of tracked GNSS satellites. This reset in the position filter is accompanied by degradation in the positioning accuracy, which is also discussed herein.

Description: [1]  This work provides a relative intercalibration of the high-energy proton channels from the Energetic Particle Sensors (EPS) flown on the Geostationary Operational Environmental Satellites (GOES) since 1994 using a technique that depends on features that arise during high solar wind dynamic pressure. Based on observations of solar energetic protons from polar-orbiting and geostationary satellites (1998-2013), solar proton fluxes are isotropic at geostationary orbit during periods of high solar wind dynamic pressure ( P dyn  〉 5 − 10 nPa). The observed isotropy results from the solar proton fluxes having rigidities (momenta per unit charge) greater than their geomagnetic cutoffs over the complete energy and angular responses of the satellite-borne detector. (The cutoff in a given direction is the rigidity below which an interplanetary particle cannot reach that location.) Under these conditions, we determine the relative responses of the EPS flown on GOES-8 through -15. These detectors are widely used for alerts of the radiation hazard posed to spacecraft and humans by solar energetic particle events; therefore, it is important to know their relative responses. The results of this low-scatter intercalibration analysis show that the relative responses agree to 20% or better (sometimes better than 1%). The effect of such relative calibration differences on the derived integral fluxes used by NOAA for its real-time solar radiation storm alerts is shown to be small (〈10%). This method can be used to intercalibrate solar proton detectors of different design if their broad energy response functions are carefully accounted for.

Description: The increased radiation exposure at aviation altitudes is of public interest as well as of legal relevance in many countries. The dose rates, that are elevated compared to sea-level, are mainly caused by galactic cosmic ray particles interacting with the atmosphere and producing a complex radiation field at aviation altitudes. The intensity and composition of this radiation field mainly depends on altitude, geomagnetic shielding and primary particle intensity. In this work we present a model based on Monte-Carlo simulations which retrospectively estimates secondary particle fluence as well as ambient dose equivalent rates and effective dose rates at any point in the atmosphere. This model will be used as the physical core in the PANDOCA (Professional Aviation Dose Calculator) software developed by the German Aerospace Center (DLR) for the calculation of route doses in aviation. The calculations are based on galactic cosmic ray spectra taking into account primary nuclei from hydrogen to iron by direct transport calculations of hydrogen and helium nuclei and approximating heavier nuclei by the number of protons equalling the corresponding atomic number. A comparison to experimental data recorded on several flights with a tissue equivalent proportional counter shows very good agreement between model calculations and measurements.

Description: [1]  Solar flares are explosive events on the Sun that release energetic particles, X-rays, EUV, and radio emissions that have an almost immediate impact on Earth's ionosphere-thermosphere (IT) system and/or on operational systems that are affected by IT conditions. To assess such impacts, it is key that we know how the ionosphere is modified. An objective of this paper is to evaluate how digisondes might serve in this role. Towards this end we utilize data from the Millstone Hill digisonde to reveal the height-versus-time bottom-side F-region responses to three X-class flares (X28, X8.3 and X1.7) at a middle latitude site. In terms of percent increase with respect to a pre-flare hourly mean, the long-lived (〉 15-30 min) responses to these flares maximize between about 150 and 250 km, and measurably last ~ 0.75-1.5 hours after flare maximum. The relative magnitudes of these responses are complicated by flare position on the solar disk, which determines how much of the EUV solar emissions are attenuated by the solar atmosphere. At Millstone Hill there was little measurable response to these flares near the F2-layer peak; however, at the magnetic equator location of Jicamarca, the F2-peak electron density increased by ~ 15-40%. Herein, all of these flare response characteristics are interpreted in terms of available modeling results. We propose that such digisonde data, in combination with first-principles models and high-resolution measurements of solar EUV flux emissions (e.g., from SDO/EVE), can lead us to a deeper understanding of the ionospheric photochemistry and dynamics that underlies a predictive capability.

Description: Extreme Medium-scale Traveling Ionospheric Disturbances (MSTIDs) occurred at mid-latitudes in East Asia during a geomagnetically active time on 10 November 2004. Using the Global Positioning System (GPS) observation data from Korean GPS reference stations, the characteristics of the MSTIDs on 10 November 2004 and their potential impact on GPS-based navigation systems in the Korean region are analyzed. The MSTIDs were first observed in the northeast part of South Korea at about 10:00 UT and propagated southwestward with successive wave fronts which extended from northwest to southeast. The peak-to-peak amplitudes of vertical Total Electron Content (TEC) disturbances decreased from about 29 to 10 TECU and the wavelengths lengthened from about 360 to 580 km from 12:53 to 14:38 UT. The propagation velocity of MSTID wave fronts was estimated using three nearby reference stations showing that velocity gradually decreased from about 254 m/s at 11:46 UT to 76 m/s at 21:26 UT. The ionospheric irregularities in small-scale regions accompanied by the MSTIDs were spatially and temporally varied from about 10:00 to 22:00 UT in response to the movement and intensity change of the MSTIDs. This event also generated anomalously large ionospheric spatial gradients which could cause unacceptable residual pseudorange errors for users of GPS augmentation systems. Frequent loss of the GPS signals, which occurred due to the intense ionospheric irregularities, could also degrade the continuity and availability of GPS-based navigation systems.

Description: [1]  We consider the model of the Finnish high-voltage power grid in 1978-79, for which the accurate parameters are available for calculating geomagnetically induced currents (GIC). Moving the grid at different locations across Europe gives estimates of GIC levels in this region. For calculating the geoelectric field driving GIC, we use different layered models of the ground conductivity, and 1-min geomagnetic data of the year 2003. The results show a clear concentration of large GIC in North Europe, where the peak values are about 3-5 times larger than in Central and South Europe, being up to about 200 A in this specific power grid. There are two factors contributing to this finding. First, geomagnetic variations are generally stronger in the north. Second, there are regions in the north with clearly smaller ground conductivities than typically at other areas. Both of these reasons lead to larger electric fields in the north. A very similar behaviour of GIC is found in the case when a single layered ground conductivity model is assumed everywhere. We also show that the geographic characteristics of GIC are quite insensitive to the details of the power grid model by modifying various parameters of the Finnish grid.

Description: [1]  A key goal for space weather studies is to define severe and extreme conditions that might plausibly afflict human technology. On 23 July 2012 solar active region 1520 (~141°W heliographic longitude) gave rise to a powerful coronal mass ejection (CME) with an initial speed that was determined to be 2500±500 km/s. The eruption was directed away from Earth toward 125°W longitude. STEREO-A sensors detected the CME arrival only about 19 hours later and made in situ measurements of the solar wind and interplanetary magnetic field. In this paper we address the question of what would have happened if this powerful interplanetary event had been Earthward directed. Using a well-proven geomagnetic storm forecast model, we find that the 23-24 July event would certainly have produced a geomagnetic storm that was comparable to the largest events of the 20th Century (Dst ~ -500nT). Using plausible assumptions about seasonal and time-of-day orientation of the Earth's magnetic dipole, the most extreme modeled value of storm-time disturbance would have been Dst = -1182nT. This is considerably larger than estimates for the famous Carrington storm of 1859. This finding has far reaching implications because it demonstrates that extreme space weather conditions such as those during March of 1989 or September of 1859 can happen even during a modest solar activity cycle such as the one presently underway. We argue that this extreme event should immediately be employed by the space weather community to model severe space weather effects on technological systems such as the electric power grid.

Description: The 7 th Annual NOAA Space Weather Prediction Center (SWPC)/ Commercial Space Weather Interest Group (CSWIG)/ American Commercial Space Weather Association (ACSWA) Summit was held on Tuesday April 16, 2013 during Space Weather Workshop (SWW). Government personnel and commercial space weather representatives attended in person and by telecom, many participating for the first time. The ACSWA ( http://www.acswa.us/ ) Executive committee (Drs. Geoff Crowley (Atmospheric and Space Technology Research Associates, ASTRA), Devrie Intriligator (Carmel Research Center, CRC), Robert Schunk (Space Environment Corporation, SEC), and Kent Tobiska (Space Environment Technologies, SET)) was in attendance.

Description: In November 2012, a workshop on the topic of designing spacecraft for operations in harsh radiation environments was held at Aberystwyth University ( http://juice2012.imaps.aber.ac.uk/index.shtml ). The immediate motivation was the European Space Agency (ESA) JUICE mission to Jupiter's icy moons ( http://sci.esa.int/juice/ ), for which the radiation to be encountered is a limiting factor in design of instruments. The workshop was organised as part of the Europlanet ( http://www.europlanet-ri.eu/ ) technology foresight program, and included a day of hands on tuition in radiation design tools by members of the ESA radiation design team. After this, and more conventional presentations, the meeting concluded with a discussion intended to establish a roadmap of the directions and technologies needed in the medium term. Discussions focused on the anticipated and desired developments in radiation modelling for spacecraft missions. These discussions considered the potential developments in two phases. Changes in the immediate future, particularly in relation to JUICE, and the opportunities for long-term development over approximately the next twenty years.

Description: [1]  One of the major types of solar eruption, Coronal Mass Ejections (CMEs) not only impact space weather, but also can have significant societal consequences. CMEs cause intense geomagnetic storms and drive fast mode shocks that accelerate charged particles, potentially resulting in enhanced radiation levels both in ions and electrons. Human and technological assets in space can be endangered as a result. CMEs are also the major contributor to generating large amplitude Geomagnetically Induced Currents (GICs), which are a source of concern for power grid safety. Due to their space weather significance, forecasting the evolution and impacts of CMEs has become a much-desired capability for space weather operations worldwide. Based on our operational experience at NASA Goddard Space Weather Research Center ( http://swrc.gsfc.nasa.gov ), we present here some of the insights gained about accurately predicting CME impacts, particularly in relation to space weather operations. These include: 1. The need to maximize information to get an accurate handle of 3-dimensional (3-D) CME kinetic parameters and therefore improve CME forecast; 2. The potential use of CME simulation results for qualitative prediction of regions of space where solar energetic particles (SEPs) may be found; 3. The need to include all CMEs occurring within a ~ 24 hour period for a better representation of the CME interactions; 4. Various other important parameters in forecasting CME evolution in interplanetary space, with special emphasis on the CME propagation direction. It is noted that a future direction for our CME forecasting is to employ the ensemble modeling approach.

Description: [1]  DoSEN is an early-stage space technology research project that combines two advanced complementary radiation detection concepts with fundamental advantages over traditional dosimetry. DoSEN not only measures the energy but also the charge distribution (including neutrons) of energetic particles that affect human (and robotic) health in a way not presently possible with current dosimeters. For heavy ions and protons, DoSEN provides a direct measurement of the Lineal Energy Transfer (LET) spectra behind shielding material. For LET measurements, DoSEN contains stacks of thin-thick Si detectors similar in design to those used for the Cosmic Ray Telescope for the Effects of Radiation (CRaTER). With LET spectra, we can now directly break down the observed spectrum of radiation into its constituent heavy ion components and through biologically-based quality factors provide not only doses and dose-rates, but also dose-equivalents, associated rates and even organ doses. DoSEN also measures neutrons from 10-100 MeV, which requires enough sensitive mass to fully absorb recoil particles that the neutrons produce. DoSEN develops the new concept of combining these independent measurements, and using the coincidence of LET measurements and neutron detection to significantly reduce backgrounds in each measurement. The background suppression through use of coincidence allows for significant reductions in size, mass, and power needed to provide measurements of dose, neutron dose, dose-equivalents, LET spectra, and organ doses. Thus, we introduce the DoSEN concept: a promising low mass instrument that detects the full spectrum of energetic particles, heavy ions and neutrons to determine biological impact of radiation in space.

Description: [1]  The Nowcast of Atmospheric Ionizing Radiation for Aviation Safety (NAIRAS) is a real-time, global, physics-based model used to assess radiation exposure to commercial aircrews and passengers. The model is a free-running physics-based model in the sense that there are no adjustment factors applied to nudge the model into agreement with measurements. The model predicts dosimetric quantities in the atmosphere from both galactic cosmic rays (GCR) and solar energetic particles (SEP), including the response of the geomagnetic field to interplanetary dynamical processes and its subsequent influence on atmospheric dose. The focus of this paper is on atmospheric GCR exposure during geomagnetically quiet conditions, with three main objectives. First, provide detailed descriptions of the NAIRAS GCR transport and dosimetry methodologies. Second, present a climatology of effective dose and ambient dose equivalent rates at typical commercial airline altitudes representative of solar cycle maximum and solar cycle minimum conditions, and spanning the full range of geomagnetic cutoff rigidities. Third, conduct an initial validation of the NAIRAS model by comparing predictions of ambient dose equivalent rates with tabulated reference measurement data and recent aircraft radiation measurements taken in 2008 during the minimum between solar cycle 23 and solar cycle 24. By applying the criterion of the International Commission on Radiation Units and Measurements (ICRU) on acceptable levels of aircraft radiation dose uncertainty for ambient dose equivalent greater than or equal to an annual dose of 1 mSv, the NAIRAS model is within 25% of the measured data, which falls within the ICRU acceptable uncertainty limit of 30%. The NAIRAS model predictions of ambient dose equivalent rate are generally within 50% of the measured data for any single-point comparison. The largest differences occur at low latitudes and high cutoffs were the radiation dose level is low. Nevertheless, analysis suggests that these single-point differences will be within 30% when a new deterministic pion-initiated electromagnetic cascade code is integrated into NAIRAS, an effort which is currently underway.

Description: Little was known about space weather in the middle of the 18 th century, yet beginning in 1600 the work of a few pioneering scientists led to breakthroughs and insights that would allow for the first space weather prediction to be made in 1749.

Description: Key Points Scientists prioritize forecasting higher than do satellite operators Scientists deemphasize some phenomena vital to satellite operations Understanding priorities can expand the societal return on science investment

Description: Key Points Need for validated measurements of radiation environment

Description: [1]  This paper reports the metrics-based results of the D st index part of the 2008-2009 GEM Metrics Challenge. The 2008-2009 GEM Metrics Challenge asked modelers to submit results for four geomagnetic storm events and five different types of observations that can be modeled by statistical, climatological or physics-based models of the magnetosphere-ionosphere system. We present the results of thirty model settings that were run at the Community Coordinated Modeling Center and at the institutions of various modelers for these events. To measure the performance of each of the models against the observations, we use comparisons of one-hour averaged model data with the D st index issued by the World Data Center for Geomagnetism, Kyoto, Japan, and direct comparison of one-minute model data with the one-minute D st index calculated by the United States Geological Survey. The latter index can be used to calculate spectral variability of model outputs in comparison to the index. We find that model rankings vary widely by skill score used. None of the models consistently perform best for all events. We find that empirical models perform well in general. Magnetohydrodynamics-based models of the global magnetosphere with inner magnetosphere physics (ring current model) included and stand-alone ring current models with properly defined boundary conditions perform well and are able to match or surpass results from empirical models. Unlike in similar studies, the statistical models used in this study found their challenge in the weakest events rather than the strongest events.

Description: ABSTRACT [1]  We describe the introduction of the first all-sky imaging system for low-light-level optical observations of the disturbed ionosphere over mid-latitude Europe. Using 6300 Å auroral emissions that come from the 200-400 km altitude range, we demonstrate that sub-visual optical patterns spanning the European continent can be obtained from a single site in Italy. Pilot observations during the 26-27 September 2011 geomagnetic storm show that the diffuse aurora's low latitude boundary can be used to locate where the poleward wall of the ionospheric trough is located. This relates directly to regions of radiowave disruptions caused by the precipitation of energetic particles from the magnetospheric plasma sheet that move to lower latitudes during space weather events. Images of stable auroral red (SAR) arcs can be used to track the magnetospheric ring current and plasmapause location, a second region of radiowave interference. Comparisons with ground-based and satellite observations of the ionosphere during the same storm demonstrate how ASI images reveal the lowest energy components of magnetospheric input to the ionosphere-thermosphere system. Such observations can be used, potentially, for both now-casting of storm effects spanning Europe, and for retrospective validation of existing models of space weather impacts at sub-auroral locations.

Description: [1]  The U.S. Government shutdown from October 1–17, 2013 significantly affected U.S. and global aviation radiation monitoring. The closure occurred just as a S2 radiation storm was in progress with an average dose rate of 20 μSv hr -1 . We estimate that during the radiation event period, one-half million passengers were flying in the affected zone and, of this population, approximately 20 would have received sufficient dose to contract fatal cancer in their lifetimes. The radiation environment can be treated like any other risk-prone weather event, e.g., rain, snow, icing, clear air turbulence, convective weather, or volcanic ash, and should be made available to flight crews in a timely way across the entire air traffic management system. The shutdown highlighted the need for active operational monitoring of the global radiation environment. Aviation radiation risk mitigation steps are simple and straightforward, i.e., fly at a lower altitude and/or use a more equatorward route. Public tools and media methods are also needed from the space weather scientific and operational communities to provide this information in a timely and accessible manner to the flying public.

Description: [1]  This paper reviews the effects of geomagnetic activity of solar cycle 24 from 2011 through mid-2013 on the Federal Aviation Administration's Wide Area Augmentation System (WAAS) navigation service in the US, to identify a) major impacts and their severity compared with the previous cycle, and b) effects in new service regions of North America added since last solar cycle. We examine two cases: a storm that reduced service coverage for several hours, and ionospheric scintillation that led to anomalous receiver tracking. Using the October 24-25, 2011 storm as an example, we examine WAAS operational system coverage for the conterminous US (CONUS). The WAAS algorithm upgrade to ionospheric estimation, in effect since late 2011, is able to mitigate the daytime coverage loss, but not the nighttime loss. We correlate WAAS availability to maps of the storm plasma generated with the data assimilative model IDA4D, which show a local nighttime co-rotating persistent plume of plasma extending from Florida across central CONUS. We study the effect of scintillation on October 9, 2012 on the WAAS reference station at Fairbanks, Alaska. Data from a nearby scintillation monitor in Gakona and all-sky imaging of aurora at Poker Flat corroborate the event. Anomalous receiver processing triggered by scintillation reduces accuracy at Fairbanks for a few minutes. Users experiencing similar effects would have their confidence bounds inflated, possibly trading off service continuity for safety. The activity to date in solar cycle 24 has had minor effects on WAAS service coverage, mainly occurring in Alaska and Canada.

Description: [1]  Extreme space weather events are known to cause adverse impacts on critical modern day technological infrastructure such as high-voltage electric power transmission grids. On 23 July 2012, NASA's Solar Terrestrial Relations Observatory-Ahead (STEREO-A) spacecraft observed in situ an extremely fast coronal mass ejection (CME) that traveled 0.96 astronomical units (∼1 AU) in about 19 h. Here we use the Space Weather Modeling Framework (SWMF) to perform a simulation of this rare CME. We consider STEREO-A in situ observations to represent the upstream L1 solar wind boundary conditions. The goal of this study is to examine what would have happened if this Rare-type CME was Earth-bound. Global SWMF-generated ground geomagnetic field perturbations are used to compute the simulated induced geoelectric field at specific ground-based active INTERMAGNET magnetometer sites. Simulation results show that while modeled global SYM-H index, a high-resolution equivalent of the D s t index, was comparable to previously observed severe geomagnetic storms such as the Halloween 2003 storm, the 23 July CME would have produced some of the largest geomagnetically induced electric fields, making it very geoeffective. These results have important practical applications for risk management of electrical power grids.

Description: [1]  During the past decade engineering-grade magnetic field measurements from the low Earth orbiting (LEO) Iridium constellation of communication satellites have been available to the geospace science community as a tool to map field-aligned currents. The Active Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE) applied to Iridium measurements markedly improved the temporal and spatial resolution of these data. We developed new methods to compare data from the latest improvement to AMPERE with those from a constellation of four LEO Defense Meteorological Satellite Program (DMSP) spacecraft that carry high-resolution magnetometers. To perform the comparisons we transformed all data to a common coordinate frame and altitude (110 km) and developed a means of computing spacecraft magnetic conjunctions. These conjunctions yield discrepancies in the magnetic field perturbations measured at each proximate spacecraft. During the geomagnetic disturbance of May 29–30 2010, the vector differences in the horizontal perturbations at closest approach (typically a few tens of kilometers) had mean, median, and standard deviation values of 132 nT, 112 nT, and 90 nT, respectively. The DMSP spacecraft tend to report larger perturbations in the northern polar cap and cusp regions, especially during active intervals. We attribute some of the differences to limitations of spacecraft-attitude knowledge that propagate into AMPERE data. Overall, for the magnetic storm, we provide clear evidence that AMPERE data can provide high-resolution auroral zone data in good agreement with DMSP data for use in data assimilation algorithms. Such dual-use commercial data can provide important global augmentation to the nation's space weather monitoring capabilities.