Ionospheric response to the corotating interaction region-driven geomagnetic storm of October 2002

Unlike the geomagnetic storms produced by coronal mass ejections (CMEs), the storms generated by corotating interaction regions (CIRs) are not manifested by dramatic enhancements of the ring current. The CIR-driven storms are however capable of producing other phenomena typical for the magnetic storms such as relativistic particle acceleration, enhanced magnetospheric convection and ionospheric heating. This paper examines ionospheric plasma anomalies produced by a CIR-driven storm in the middle- and high-latitude ionosphere with a specific focus on the polar cap region. The moderate magnetic storm which took place on 14–17 October 2002 has been used as an example of the CIR-driven event. Four-dimensional tomographic reconstructions of the ionospheric plasma density using measurements of the total electron content along ray paths of GPS signals allow us to reveal the large-scale structure of storm-induced ionospheric anomalies. The tomographic reconstructions are compared with the data obtained by digital ionosonde located at Eureka station near the geomagnetic north pole. The morphology and dynamics of the observed ionospheric anomalies is compared qualitatively to the ionospheric anomalies produced by major CME-driven storms. It is demonstrated that the CIR-driven storm of October 2002 was able to produce ionospheric anomalies comparable to those produced by CME-driven storms of much greater Dst magnitude. This study represents an important step in linking the tomographic GPS reconstructions with the data from ground-based network of digital ionosondes

Minimization of Fungicidal Applications Against Potato Late Blight in the North Caucasian Region: Use of the “Agrodozor” System

Late blight is considered to be the most devastating potato disease, which control requires application of fungicides able to significantly contaminate the environment and accumulate in agricultural products. Pesticide load on potato fields can be reduced via optimization of the scheme of protective treatments. Such optimization can be performed using a mathematical simulator describing the dependence of late blight-caused yield losses on the weather data and an “Agrodozor” decision support system (DSS). The performed analysis of a situation in the regions of the North Caucasus allowed us to determine three zones differing in the disease harmfulness and characterized by potential yield losses at the level of <10, 10-20, and >20 % and the probability of disease appearance in field during 30, 77, and 90 % of seasons, respectively. Using the “Agrodozor” DSS, we calculated the optimum dates of fungicidal treatments for these zones and showed that, comparing to the commonly used routine scheme of treatments, the use of this DSS provides a significant reduction of the number of such treatments and, therefore, the corresponding costs for their arrangement, as well as reduction of the total toxicity index of the required protective measures

Ensemble downscaling in coupled solar wind-magnetosphere modeling for space weather forecasting

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 modeling, 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 modeling. To demonstrate the benefit of this approach, we first approximate solar wind model output by smoothing solar wind observations with an 8 h 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 parameterization 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

Extreme geomagnetic disturbances due to shocks within CMEs

We report on features of solar wind-magnetosphere coupling elicited by shocks propagating through coronal mass ejections (CMEs) by analyzing the intense geomagnetic storm of 6 August 1998. During this event, the dynamic pressure enhancement at the shock combined with a simultaneous increase in the southward component of the magnetic field resulted in a large earthward retreat of Earth\u27s magnetopause, which remained close to geosynchronous orbit for more than 4 h. This occurred despite the fact that both shock and CME were weak and relatively slow. Another similar example of a weak shock inside a slow CME resulting in an intense geomagnetic storm is the 30 September 2012 event, which strongly depleted the outer radiation belt. We discuss the potential of shocks inside CMEs to cause large geomagnetic effects at Earth, including magnetopause shadowing

Nonequilibrium Phenomena in the Magnetosphere: Phase Transition, Self-organized Criticality and Turbulence

The magnetosphere is a large scale natural system powered by the solar wind that exhibits many nonequilibrium phenomena. A wide range of these phenomena are driven directly by the solar wind or arise from the storage-release processes internal to the magnetosphere. Under the influnce by the turbulent solar wind, the magnetosphere during geomagnetically active periods is far from equilibrium and storms and substorms are essentially non-equilibrium phenomena. In spite of the distributed nature of the physical processes and the apparent irregular behavior, there is a remarkable coherence in the magnetospheric response during substorms and the entire magnetosphere behaves as a global dynamical system. Alongwith the global features, the magnetosphere exhibits many multi-scale and intermittent characteristics. These features of the magnetosphere have been studied in terms of phase transitions, self-organized criticality and turbulence. In the phase transition scenario the global features are modeled as first-order transitions and the multi-scale behavior is interpreted as a manifestation of the scale-free nature of criticality in second order phase transitions. In the self-organized criticality framework substorms are considered as avalanches in the system when criticality is reached. Many features of the magnetosphere, in particular the power law dependence of scale sizes, can be viewed as a feature of a turbulent system.The common theme underlying these approaches is the recognition that the nonequilibrium phenomena in the magnetosphere could be understood in terms of processes generic to such systems. In many cases the power-law behavior of the magnetosphere seen in many observations is the starting point for these studies. This chapter is an overview of the recent understanding achieved using these different approaches, and identifies the common issues and differences.National Science Foundation: ATM-0119196, ATM-0318629, DMS-0417800 National Aeronautics and Space Administration: NNG04E37

Geoeffectiveness and efficiency of CIR, Sheath and ICME in generation of magnetic storms

We investigate relative role of various types of solar wind streams in generation of magnetic storms. On the basis of the OMNI data of interplanetary measurements for the period of 1976-2000 we analyze 798 geomagnetic storms with Dst < -50 nT and their interplanetary sources: corotating interaction regions (CIR), interplanetary CME (ICME) including magnetic clouds (MC) and Ejecta and compression regions Sheath before both types of ICME. For various types of solar wind we study following relative characteristics: occurrence rate; mass, momentum, energy and magnetic fluxes; probability of generation of magnetic storm (geoeffectiveness) and efficiency of process of this generation. Obtained results show that despite magnetic clouds have lower occurrence rate and lower efficiency than CIR and Sheath they play an essential role in generation of magnetic storms due to higher geoeffectiveness of storm generation (i.e higher probability to contain large and long-term southward IMF Bz component).Comment: 23 pages, 4 figures, 3 tables, submitted to JGR special issue "Response of Geospace to High-Speed Streams

Perturbed Input Ensemble Modeling With the Space Weather Modeling Framework

To assess the effect of uncertainties in solar wind driving on the predictions from the operational configuration of the Space Weather Modeling Framework, we have developed a nonparametric method for generating multiple possible realizations of the solar wind just upstream of the bow shock, based on observations near the first Lagrangian point. We have applied this method to the solar wind inputs at the upstream boundary of Space Weather Modeling Framework and have simulated the geomagnetic storm of 5 April 2010. We ran a 40‐member ensemble for this event and have used this ensemble to quantify the uncertainty in the predicted Sym‐H index and ground magnetic disturbances due to the uncertainty in the upstream boundary conditions. Both the ensemble mean and the unperturbed simulation tend to underpredict the magnitude of Sym‐H in the quiet interval before the storm and overpredict in the storm itself, consistent with previous work. The ensemble mean is a more accurate predictor of Sym‐H, improving the mean absolute error by nearly 2 nT for this interval and displaying a smaller bias. We also examine the uncertainty in predicted maxima in ground magnetic disturbances. The confidence intervals are typically narrow during periods where the predicted dBH/dt is low. The confidence intervals are often much wider where the median prediction is for enhanced dBH/dt. The ensemble also allows us to identify intervals of activity that cannot be explained by uncertainty in the solar wind driver, driving further model improvements. This work demonstrates the feasibility and importance of ensemble modeling for space weather applications.Plain Language SummaryForecasts of space weather usually rely on spacecraft measurements of the solar wind from about a million miles away from Earth. Like water flowing toward a rock in a stream, measurements at a single point upstream may not reflect exactly what will hit the Earth. Forecasts that are driven by these measurements have uncertainty due to the uncertainty in the measurements driving the forecast models. We have developed a technique to estimate the uncertainty on space weather predictions using 7 years of solar wind measurements from two satellites. We have performed computer simulations of the same geomagnetic storm 41 times. In each simulation, the inputs were modified slightly each time to reflect the uncertainty in the measurements. By considering the set of simulations as a whole, we have shown that space weather forecasts can be improved by accounting for the uncertainty in the input data. We have also shown that accounting for uncertainty in the data driving, the model can highlight where incorrect forecasts are due to the uncertainty, as well as where they are due to inadequacies in the model itself. This work shows the importance of ensemble methods and accounting for uncertainties in space weather simulation and forecasting.Key PointsA new nonparametric method for drawing different realizations of solar wind data to drive magnetospheric models is derivedThe new method is used to obtain uncertainties on predicted geophysical indices from the operational Space Weather Modeling FrameworkModel skill can be improved by considering the uncertainty on model inputPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146472/1/swe20747_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146472/2/swe20747.pd

Adsorption of benzene on Si(100) from first principles

Adsorption of benzene on the Si(100) surface is studied from first principles. We find that the most stable configuration is a tetra-$\sigma$-bonded structure characterized by one C-C double bond and four C-Si bonds. A similar structure, obtained by rotating the benzene molecule by 90 degrees, lies slightly higher in energy. However, rather narrow wells on the potential energy surface characterize these adsorption configurations. A benzene molecule impinging on the Si surface is most likely to be adsorbed in one of three different di-$\sigma$-bonded, metastable structures, characterized by two C-Si bonds, and eventually converts into the lowest-energy configurations. These results are consistent with recent experiments.Comment: 4 pages, RevTex, 2 PostScript gzipped figure

REGIONAL EXPERIENCE OF ORGANIZING OF ANTIEPIDEMIC MEASURES DIRECTED TO THE PREVENTING OF DELIVERY AND SPREADING OF SEVERE ACUTE RESPIRATORY SYNDROME IN OMSK REGION

Characteristics of factors, defining the possibility of severe acute respiratory syndrome delivery into the territory of Omsk region are given. The data of complex approach for organization and anti-epidemic measures at the region level for preventing of SARS delivery and spreading are presented. Problems of scientific and practical character, that need to be solved for effective counteraction with epidemic spreading of «atypical pneumonia» are discussed

Recovery phase of magnetic storms induced by different interplanetary drivers

Statistical analysis of Dst behaviour during recovery phase of magnetic storms induced by different types of interplanetary drivers is made on the basis of OMNI data in period 1976-2000. We study storms induced by ICMEs (including magnetic clouds (MC) and Ejecta) and both types of compressed regions: corotating interaction regions (CIR) and Sheaths. The shortest, moderate and longest durations of recovery phase are observed in ICME-, CIR-, and Sheath-induced storms, respectively. Recovery phases of strong ($Dst_{min} < -100$ nT) magnetic storms are well approximated by hyperbolic functions $Dst(t)= a/(1+t/\tau_h)$ with constant $\tau_h$ times for all types of drivers while for moderate ($-100 < Dst_{min} < -50$ nT) storms $Dst$ profile can not be approximated by hyperbolic function with constant $\tau_h$ because hyperbolic time $\tau_h$ increases with increasing time of recovery phase. Relation between duration and value $Dst_{min}$ for storms induced by ICME and Sheath has 2 parts: $Dst_{min}$ and duration correlate at small durations while they anticorrelate at large durations.Comment: 18 pages, 4 figures, 2 tables, submitted to JGR special issue "Response of Geospace to High-Speed Streams