The dynamics of solar activity and anomalous weather of summer 2010: 2. Relationship with the active longitude zone; effects in the west and east

We confirm the close synoptic relationship of the sectoral structure of the Sun’s magnetic field of the with the near-Earth tropospheric pressure with a case study of three European points (Troitsk, Rome, Jungfrau) in the period of the anomalously hot summer of June–August 2010. We substantiate the position that such a relationship was fostered by the anomalously low solar activity as a result of superposition of the minima of the 22- and 180-year cycles. Sectoral analysis of the solar-tropospheric relationships has shown that the appearance of a blocking anticyclone in the Moscow suburbs, its expansion to Rome and Jungfrau, and subsequent retreat at first from these points, and then from the Moscow suburbs was closely related to solar activity phenomena producing, according to contemporary notions, cyclonic activity, shown by simulation of the Earth’s electric field.     

The solar activity and the summer rainfall in the mediterranean

Summary This study deals with the influence of sunspots on the summer rainfall of 30 selected Stations of the Mediterranean, having records covering at least 4 cycles of sunspots. — It was found that the minimum of summer rainfall occurs near the maximum of sunspots and the maximum of rainfall in the beginning or at the end of sunspots cycle. — The variation of summer rainfall during the sunspots cycle presents four typesA: simple oscillation,B andC: double oscillation andD: triple oscillation.

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Résumé Cette étude s'occupe de l'influence des taches solaires sur la pluie estivale des 30 Stations de la Mediterranée, choisies parmi celles qui couvrent au moins 4 cycles des taches solaires. — On a trouvé que le minimum des pluies estivales a lieu près du maximum des taches solaires et que le maximum des pluies aussi a lieu au commencement ou à la fin du cycle de l'activité solaire. — La variation de la pluie durant le cercle des taches solaires presente 4 typesA: une oscillation simple,B etC une oscillation double etD une oscillation triple.

     

The northern annular mode in summer and its relation to solar activity variations in the GISS ModelE

The northern annular mode (NAM) has been successfully used in several studies to understand the variability of the winter atmosphere and its modulation by solar activity. The variability of summer circulation can also be described by the leading empirical orthogonal function (EOF) of geopotential heights. We compare the annular modes of the summer geopotential heights in the northern hemisphere stratosphere and troposphere in the Goddard Institute for Space Studies (GISS) ModelE with those in the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis. In the stratosphere, the summer NAM obtained from NCEP/NCAR reanalysis as well as from the ModelE simulations has the same sign throughout the northern hemisphere, but shows greater variability at low latitudes. The patterns in both analyses are consistent with the interpretation that low NAM conditions represent an enhancement of the seasonal difference between the summer and the annual averages of geopotential height, temperature and velocity distributions, while the reverse holds for high NAM conditions. Composite analysis of high and low NAM cases in both model and observation suggests that the summer stratosphere is more “summer-like” when the solar activity is near a maximum. This means that the zonal easterly wind flow is stronger and the temperature is higher than normal. Thus increased irradiance favors a low summer NAM. A quantitative comparison of the anti-correlation between the NAM and the solar forcing is presented in the model and in the observation, both of which show lower/higher NAM index in solar maximum/minimum conditions. The temperature fluctuations in simulated solar minimum conditions are greater than in solar maximum throughout the summer stratosphere.The summer NAM in the troposphere obtained from NCEP/NCAR reanalysis has a dipolar zonal structure with maximum variability over the Asian monsoon region. The corresponding EOF in ModelE has a qualitatively similar structure but with less variability in the Asian monsoon region which is displaced eastward of its observed position. In both the NCEP/NCAR reanalysis and the GCM the negative anomalies associated with the NAM in the Euro-Atlantic and Aleutian island regions are enhanced in the solar minimum conditions, though the results are not statistically significant.     

Application of synoptic-scale anomalous winds predicted by medium-range weather forecast models on the regional heavy rainfall in China in 2010

Atmospheric winds from observations and medium-range weather forecast model predictions can be physically decomposed as daily climate wind,planetary-scale anomalous wind,and synoptic-scale anomalous wind.The 850 hPa synoptic-scale anomalous winds were extracted from the numerical model outputs of the European Centre for Medium-Range Weather Forecasts(ECMWF) and the NCEP Global Forecast System(GFS).The results showed that most rain bands in eastern China in 2010 were located along the anomalous convergence lines.To predict the major rain bands by these convergence lines in 2010,the accuracies of the ECMWF products were 100%,85%,and 15% for leading 3,6,and 9 days,while the GFS products showed 53%,15%,and 6% accuracies,respectively.In comparison of the regional heavy rainfalls between observation and the ECMWF model prediction,the useful leading information was about 3.1 days for direct model rain prediction and 6.7 days for convergence systems predicted by ECMWF model.     

Dynamics of thinning and destruction of the continental cratonic lithosphere: Numerical modeling

Thinning of the cratonic lithosphere is common in nature, but its destruction is not. In either case, the mechanisms for both thinning and destruction are still widely under debate. In this study, we have made a review on the processes and mechanisms of thinning and destruction of cratonic lithosphere according to previous studies of geological/geophysical observations and numerical simulations, with specific application to the North China Craton (NCC). Two main models are suggested for the thinning and destruction of the NCC, both of which are related to subduction of the oceanic lithosphere. One is the “bottom-up” model, in which the deeply subducting slab perturbs and induces upwelling from the hydrous mantle transition zone (MTZ). The upwelling produces mantle convection and erodes the bottom of the overriding lithosphere by the fluid-melt-peridotite reaction. Mineral compositions and rheological properties of the overriding lithospheric mantle are changed, allowing downward dripping of lithospheric components into the asthenosphere. Consequently, lithospheric thinning or even destruction occurs. The other is the “top-down” model, characterized by the flat subduction of oceanic slab beneath the overriding cratonic lithosphere. Dehydration reactions from the subducting slab would significantly hydrate the lithospheric mantle and decrease its rheological strength. Then the subduction angle may be changed from shallow to steep, inducing lateral upwelling of the asthenosphere. This upwelling would heat and weaken the overriding lithospheric mantle, which led to the weakened lithospheric mantle dripping into the asthenosphere. These two models have some similarities, in that both take the subducting oceanic slab and relevant fluid migration as the major driving mechanism for thinning or destruction of the overriding cratonic lithosphere. The key difference between the two models is the effective depth of the subducting oceanic slab. One is stagnation and flattening in the MTZ, whereas the other is flat subduction at the bottom of the cratonic lithosphere. In the NCC, the eastern lithosphere was likely affected by subduction of the Izanagi slab during the Mesozoic, which would have perturbed the asthenosphere and the MTZ, and induced fluid migration beneath the NCC lithosphere. The upwelling fluid may largely have controlled the reworking of the NCC lithosphere. In order to discuss and analyze these two models further, it is crucial to understand the role of fluids in the subduction zone and the MTZ. Here, we systematically discuss phase transformations of hydrous minerals and the transport processes of water in the subduction system. Furthermore, we analyze possible modes of fluid activity and the problems to explore the applied feasibility of each model. In order to achieve a comprehensive understanding of the mechanisms for thinning and destruction of cratonic lithosphere, we also consider four additional possible dynamic models: extension-induced lithospheric thinning, compression-induced lithospheric thickening and delamination, large-scale mantle convection and thermal erosion, and mantle plume erosion. Compared to the subduction-related models presented here, these four models are primarily controlled by the relatively simple and single process and mechanism (extension, compression, convection, and mantle plume, respectively), which could be the secondary driving mechanisms for the thinning and destruction of lithosphere.     

Long-term solar activity and terrestrial connections. Part I: theory

The research task described herein aims at the structuring of an analytical tool that traces the time course of geophysical phenomena, regional or global, and compares it to the course of long-term solar conditions, long-term meaning decades or a few centuries. The model is based on the premise that since in a last analysis the preponderance of atmospheric, hydrospheric, and, possibly, some aspects of geospheric phenomena are, or have been, powered by energy issuing from the sun – either now or in the past, the long-term behavior of such phenomena is ultimately connected to long-term changes occurring in the sun itself. Accordingly, the proposed research firstly derives and models a stable surrogate pattern for the long-term solar activity, secondly introduces a transfer-function algorithm for modeling the connection between the surrogate and terrestrial phenomena viewed as partners in the connection, and thirdly probes the connection outcome for episodic or unanticipated effects that may arise due to the fact that in the present context, the connection, should it exist, is very likely nonlinear. Part I of the study presents the theory of the concept, while Part II demonstrates the concepts pertinence to a number of terrestrial phenomena.This essay has been the basis of two earlier papers, one presented at The 8th International Conference of the European Union of Geosciences in Strasbourg, France, 9–13 April 1995; and the other at The 5th International Conference on Precipitation in Elounda, Crete, Greece, 14–16 June 1995.     

Analyses of hot and humid weather in Beijing city in summer and its dynamical identification

The circulation, hygrothermal property and moisture transport character of typical hot and humid weather were analyzed in Beijing areas from July 30 to August 4, 2002. It was pointed out that, under the control of subtropical anticyclone which stretches to the west and north, downdraft suppresses the lifting of lower-troposphere moisture, which makes moisture keep in the lower troposphere. That is the direct reason causing hot and humid weather. Considering the non-uniformity saturated character in real atmosphere, generalized moist potential vorticity (GMPV) equation is derived by the introduction of generalized moist potential temperature concept. The analysis of GMPV shows that negative GMPV anomaly occurs in the lower troposphere. It has indicative sense to hot and humid weather. Thus, the GMPV anomaly can be utilized to identify this kind of weather and to make a short-term prediction.     

Modeling fast ice formation and destruction in the Sea of Japan

The problems of parametric representation of the initial formation and the subsequent evolution of fast ice in freezing seas are discussed within the framework of the model of marine ice cover evolution. The mathematical form of this representation takes into account the processes of transformation of sea ice formations in open water areas in coastal regions into fast ice during its formation and inverse processes at the stage of its destruction. The parametric identification of the model was based on samples of long-term distributions of ice cover characteristics in the Sea of Japan, as well as the distributions of air temperature and wind speeds over sea water area. The model can be used to predict the state of fast ice in the ice cover of the Sea of Japan.     

High-latitude methane sulphonic acid variability and solar activity: the role of the total solar irradiance

The direct impact of solar activity on climate has been widely studied through Total Solar Irradiance (TSI). Biological processes also impact climate and are deeply affected by TSI. Marine phytoplankton emissions into the atmosphere have been proposed to change cloud albedo through cloud formation. In this work, we use wavelet analysis to investigate the decadal relation between high-latitude concentrations of methane sulphonic acid, a product of seawater algae, and TSI. We found that some of the methane sulphonic acid main periodicities coincide with periods of solar activity periods.     

淀山湖蓝藻水华高发期叶绿素a动态及相关环境因子分析

根据2008年5-9月专项监测数据,分析蓝藻水华高发期淀山湖叶绿素a浓度的动态变化,及其与pH、溶解氧、TN、TP等环境因子的相互关系.结果表明,淀山湖蓝藻水华高发期叶绿素a存在明显的时间变化和空间分异,特别是叶绿素a的峰值共对应了3次水华暴发过程.其叶绿素a对数与总磷对数呈极显著正相关,与硝酸盐氮、TN/TP呈负相关...     

Magnetohydrodynamic simulation of a solar flare: 1. Current sheet in the corona

The results of modeling the preflare situation in the solar corona, obtained using a numerical solution for a complete set of three-dimensional MHD equations, are reviewed. Any assumptions concerning the flare development character or the active region’s behavior before a flare are not introduced. The initial and boundary conditions on the photosphere are specified from magnetic field measurements before a flare. The photospheric field sources are approximated by magnetic dipoles. The usage of the PERESVET program indicated that a current sheet is formed in the vicinity of a singular magnetic field line in the corona. The sheet is formed due to disturbances coming from the photosphere. The energy necessary for a flare is stored in the current sheet magnetic field during 2–3 days. The main construction principles of the PERESVET program, which makes it possible to use the maps of a measured photospheric field as boundary conditions, are presented.     

Fractal dimension of changes in the solar magnetic field energy and quasi-biennial solar activity variations

Using the data of 1960–1999 on solar magnetic fields on the source surface and the Higuchi method, the fractal dimension of changes in the solar magnetic field energy at various heliolatitudes and in different time intervals is analyzed. The fractal dimension obtained on a moving 1-year interval displays substantial time variations. The 11-year cycle, which dominates at high latitudes, and quasi-biennial variations (QBVs), which dominate at low latitudes and are similar to QBVs of solar activity indices, are traced in these variations. Thus, solar QBVs that appear in all heliomagnetic activity indices are also present in the fractal structure of the solar magnetic field variations.     

Effects of solar eclipses in the ionosphere: Results of Doppler sounding: 1. Experimental data

The results of experimental studies of variations in the Doppler frequency shift at a vertical radio path caused by partial solar eclipses are presented. Eclipses were observed near Kharkov in 1999?C2008. The eclipse phase varied from 0.24 to 0.78. It is shown that the eclipses caused sign-changing variations in the Doppler frequency shift, deformations of the Doppler spectra, and also quasi-periodic changes in the Doppler frequency shift. This was manifested in changes in the electron concentration, generation of wave processes, and plasma motions caused by the eclipses.     

Dynamics of accelerated electron beams and X rays in solar flares with sub-THz radiation

Unique measurements by a solar submillimeter radio telescope (SST) have been carried out in the sub-THz radiation at 212 and 405 THz over the past decade. The spectrum of RF radiation in this region increased with frequency for the three flares of November 2 and 4, 2003, and December 6, 2006, and the flux value reached 5 × 10³?2 × 10⁴ sfu at 405 GHz (Kaufman et al., 2009). In this work, we consider a set of nonlinear equations for an accelerated electrons beam and the Langmuir wave energy density. The distribution functions of the accelerated electron beam and wave energy density are calculated taking into account Coulomb collisions, electron scattering by waves, and wave scattering by plasma ions. In addition, the source of accelerated particles and the heat level of the Langmuir turbulence are specified. The beam and plasma parameters are chosen based on the aims of a problem. The plasma concentration varies from n = 10¹³ to 10¹⁵ cm^?3, the electron plasma frequency f _p = (3 × 10¹⁰?3 × 10¹¹) Hz in this case. The ratio of plasma and beam concentrations, sufficient to explain the value of the radio flux at a frequency of 300 GHz, is n _b/n = 10^?3. The Langmuir turbulence is excited due to the instability of the accelerated electron beam with an initial distribution function of the ??bump-in-tail?? type. Then, the parameters of radiowaves are calculated in the sub-THz range under the assumption of coalescence of two plasma waves. The calculation results show that a sub-THz radio flux can be obtained under the condition of injection of accelerated electrons. The fine time structure of radio flux observed is easily simulated based on this statement by the pulsed time structure of electron beams and their dynamics in overdense plasma. X-ray and gamma radiation was recorded during the events under study. Hard X-ray radiation is bremsstrahlung radiation from accelerated electron beams.     

Superconcentration of photospheric sources of the large-scale open solar magnetic field in the main zone of active longitudes, differential rotation blocking, and origination of the four-sector structure. 1. The field and solar activity dynamics

The phenomena of superconcentration of the large-scale field photospheric sources in the main zone of active longitudes, blocking of regular differential rotation by these sources, and origination of the four-sector structure of the solar magnetic field during the decline phase of cycle 23 have been considered in more detail and taking into account the polar correction. It has been indicated that superconcentration was formed due to the penetration of photospheric sources into the zone from the western surroundings of this zone and owing to the generation of the large-scale field in the zone itself. The dynamics of a blocking-induced complex MHD disturbance with reflected from the zone and reconnecting photospheric sources of negative and positive polarity, respectively, and the transformation of the bisector structure into the four-sector one have been considered. It has been indicated that the dynamics of this MHD disturbance was responsible for that of associated solar activity: the generation of sunspot groups, appearance of flares, and, finally, origination of a powerful heliospheric storm and the solar-terrestrial extrastorm of July 22–27, 2004.     

Dynamics of three-block assemblies with unilateral deformable contacts. Part 1: contact modelling

As far as the dynamics of multibody systems is concerned, a brief review has been performed in order to frame the dynamic response of a trilith (the simplest scheme of a colonnade belonging to a temple) into a wide theoretical background. Under the assumption of rigid bodies, two different approaches can be found in the literature: rigid or deformable contacts formulation. In this paper, an effort is made at outlining the principle of rigid contact formulation and of deformable contact formulation. The latter approach can be assumed within the framework of the distinct element method; for this purpose a model of deformable contact has been proposed in order to simulate the real behaviour of stone joints. The sample application referred to the trilith will be presented in Part 2. Copyright © 1999 John Wiley & Sons, Ltd.     

Dynamics of equilibrium upset and electromagnetic energy transformation in the geomagnetotail: A theory and simulation using particles. 3. Versions of formation of thin current sheets

The final part of the study is devoted to the process of rapid reconfiguration of the geomagnetotail after the upset of the equilibrium, i.e., to substorm activation. Such a version of spontaneous formation of nonlinear kinetic small-scale structures at the site occupied by an initial current sheet (CS), which results in the formation of a specific equilibrium current structure with strong ion anisotropy (forced kinetic current sheet, FKCS), has been revealed in the course of numerical simulation. This reconfiguration “channel” is realized when the relative value of the magnetic field component normal to CS is smaller than a certain critical value. In this case the disturbance intensity is SPONTANEOUSLY settled at a certain final level at the late stages. The obtained results are compared with the previous study of the system evolution under the action of the external trigger. The physical causes and specific features of different CS evolution regimes are considered. The studied plasma mechanisms are responsible for the effects of rapid energy transformation—magnetic field “annihilation”—that took place in the geomagnetotail.     

Global lightning formation at a minimum and maximum of solar activity according to the observations of the Schumann resonance on the Kola Peninsula

On the basis of the two-component measurements of the atmospheric noise electromagnetic field on the Kola Peninsula, a change in the first Schumann resonance (SR-1) as an indicator of global lightning formation is studied depending on the level of galactic cosmic rays (GCRs). It is found that the effect of GCRs is most evident during five months: in January and from September to December; in this case the SR-1 intensity in 2001 was higher than the level of 2007 by a factor of 1.5 and more. This effect almost disappears when the regime of the Northern Hemisphere changes into the summer regime. It is assumed that an increase in the GCR intensity results in an increase in the lightning occurrence frequency; however, the probability that the power of each lightning stroke decreases owing to an early disruption of the charge separation and accumulation processes in a thundercloud increases; on the contrary, a decrease in the GCR intensity decreases lightning stroke occurrence frequency and simultaneously increases the probability of accumulating a higher energy by a thundercloud and increasing the lightning power to the maximum possible values.