Improving solar wind persistence forecasts: removing transient space weather events, and using observations away from the Sun-Earth line

This study demonstrates two significant ways of improving persistence forecasts of the solar wind, which exploit the relatively unchanging nature of the ambient solar wind to provide 27 day forecasts, when using data from the Lagrangian L1 point. Such forecasts are useful as a prediction tool for the ambient wind, and for benchmarking of solar wind models. We show that solar wind persistence forecasts can be improved by removing transient solar wind features such as coronal mass ejections (CMEs). Using CME indicators to automatically identify CME-contaminated periods in ACE data from 1998 to 2011, and replacing these with solar wind from a previous synodic rotation, persistence forecasts improve (relative to a baseline): skill scores for Bz, a crucial parameter for determining solar wind geoeffectiveness, improve by 7.7 percentage points when using a proton temperature-based indicator with good operational potential. We also show that persistence forecasts can be improved by using measurements away from L1, to reduce the requirement on coronal stability for an entire synodic period, at the cost of reduced lead time. Using STEREO-B data from 2007 to 2013 to create such a reduced lead time persistence forecast, we show that Bz skill scores improve by 17.1 percentage points relative to ACE. Finally, we report on implications for persistence forecasts from any future missions to the L5 Lagrangian point and on the successful operational implementation (in spring 2015) of the normal (ACE-based) and reduced lead time (STEREO-based) persistence forecasts in the Met Office's Space Weather Operations Centre, as well as plans for future improvements

Forecasting the Arrival Time of Coronal Mass Ejections: Analysis of the CCMC CME Scoreboard

Accurate forecasting of the properties of coronal mass ejections (CMEs) as they approach Earth is now recognized as an important strategic objective for both NOAA and NASA. The time of arrival of such events is a key parameter, one that had been anticipated to be relatively straightforward to constrain. In this study, we analyze forecasts submitted to the Community Coordinated Modeling Center at NASA's Goddard Space Flight Center over the last 6 years to answer the following questions: (1) How well do these models forecast the arrival time of CME-driven shocks? (2) What are the uncertainties associated with these forecasts? (3) Which model(s) perform best? (4) Have the models become more accurate during the past 6 years? We analyze all forecasts made by 32 models from 2013 through mid-2018, and additionally focus on 28 events, all of which were forecasted by six models. We find that the models are generally able to predict CME-shock arrival times, in an average sense, to within 10 hr, but with standard deviations often exceeding 20 hr. The best performers, on the other hand, maintained a mean error (bias) of 1 hr, a mean absolute error of 13 hr, and a precision (standard deviation) of 15 hr. Finally, there is no evidence that the forecasts have become more accurate during this interval. We discuss the intrinsic simplifications of thevarious models analyzed, the limitations of this investigation, and suggest possible paths to improve these forecasts in the future

Neuron-Targeted Caveolin-1 Improves Molecular Signaling, Plasticity, and Behavior Dependent on the Hippocampus in Adult and Aged Mice

BACKGROUND: Studies in vitro demonstrate that neuronal membrane/lipid rafts (MLRs) establish cell polarity by clustering pro-growth receptors and tethering cytoskeletal machinery necessary for neuronal sprouting. However, the effect of MLR and MLR-associated proteins on neuronal aging is unknown. METHODS: Here we assessed the impact of neuron-targeted overexpression of a MLR scaffold protein, caveolin-1 (via a synapsin promoter; SynCav1), in the hippocampus in vivo in adult (6-months-old) and aged (20-month-old) mice on biochemical, morphologic and behavioral changes. RESULTS: SynCav1 resulted in increased expression of Cav-1, MLRs, and MLR-localization of Cav-1 and tropomyosin-related kinase B (TrkB) receptor independent of age and time post gene transfer. Cav-1 overexpression in adult mice enhanced dendritic arborization within the apical dendrites of hippocampal CA1 and granule cell neurons, effects that were also observed in aged mice, albeit to a lesser extent, indicating preserved impact of Cav-1 on structural plasticity of hippocampal neurons with age. Cav-1 overexpression enhanced contextual fear memory in adult and aged mice demonstrating improved hippocampal function. CONCLUSIONS: Neuron-targeted overexpression of Cav-1 in the adult and aged hippocampus enhances functional MLRs with corresponding roles in cell signaling and protein trafficking. The resultant structural alterations in hippocampal neurons in vivo are associated with improvements in hippocampal dependent learning and memory. Our findings suggest Cav-1 as a novel therapeutic strategy in disorders involving impaired hippocampal function