scholarly journals The North–South Asymmetry of Sunspot Relative Numbers Based on Complex Network Technique

Symmetry ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2228
Author(s):  
Hengyu Xu ◽  
Yu Fei ◽  
Chun Li ◽  
Jiajuan Liang ◽  
Xinan Tian ◽  
...  
Keyword(s):  
Nonlinear Dynamics ◽  
Complex Network ◽  
Degree Sequence ◽  
Nonlinear Behavior ◽  
Original Data ◽  
Magnetic Activity ◽  
Sunspot Activity ◽  
Data Series ◽  
The North ◽  
Visibility Graphs

Solar magnetic activity exhibits a complex nonlinear behavior, but its dynamic process has not been fully understood. As the complex network technique can better capture the dynamics of nonlinear system, the visibility graphs (VG), the horizontal visibility graphs (HVG), and the limited penetrable visibility graphs (LPVG) are applied to implement the mapping of sunspot relative numbers in the northern and southern hemispheres. The results show that these three methods can capture important information of nonlinear dynamics existing in the long-term hemispheric sunspot activity. In the presentation of the results, the network degree sequence of the HVG method changes preferentially to the original data series as well as the VG and the LPVG, while both the VG and the LPVG slightly lag behind the original time series, which provides some new ideas for the nonlinear dynamics of the hemispheric asymmetry in the two hemispheres. Meanwhile, the use of statistical feature-skewness values and complex network visibility graphs can yield some complementary information for mutual verification.

Nonlinear Dynamics of an Imperfect Microbeam Under an Axial Load and Electric Excitation

2011 ◽  
Author(s):  
Laura Ruzziconi ◽  
Mohammad I. Younis ◽  
Stefano Lenci
Keyword(s):  
Nonlinear Dynamics ◽  
Microelectromechanical Systems ◽  
Complex Dynamics ◽  
Nonlinear Behavior ◽  
Single Mode ◽  
Phase Portraits ◽  
Nonlinear Phenomena ◽  
Theoretical Point ◽  
Initial Shape ◽  
Electric Excitation

This study is motivated by the growing attention, both from a practical and a theoretical point of view, toward the nonlinear behavior of microelectromechanical systems (MEMS). We analyze the nonlinear dynamics of an imperfect microbeam under an axial force and electric excitation. The imperfection of the microbeam, typically due to microfabrication processes, is simulated assuming the microbeam to be of a shallow arched initial shape. The device has a bistable static behavior. The aim is that of illustrating the nonlinear phenomena, which arise due to the coupling of mechanical and electrical nonlinearities, and discussing their usefulness for the engineering design of the microstructure. We derive a single-mode-reduced-order model by combining the classical Galerkin technique and the Pade´ approximation. Despite its apparent simplicity, this model is able to capture the main features of the complex dynamics of the device. Extensive numerical simulations are performed using frequency response diagrams, attractor-basins phase portraits, and frequency-dynamic voltage behavior charts. We investigate the overall scenario, up to the inevitable escape, obtaining the theoretical boundaries of appearance and disappearance of the main attractors. The main features of the nonlinear dynamics are discussed, stressing their existence and their practical relevance. We focus on the coexistence of robust attractors, which leads to a considerable versatility of behavior. This is a very attractive feature in MEMS applications. The ranges of coexistence are analyzed in detail, remarkably at high values of the dynamic excitation, where the penetration of the escape (dynamic pull-in) inside the double well may prevent the safe jump between the attractors.

scholarly journals STEAD: A high-resolution daily gridded temperature dataset for Spain

2019 ◽  
Author(s):  
Roberto Serrano-Notivoli ◽  
Santiago Beguería ◽  
Martín De Luis
Keyword(s):  
Quality Control ◽  
Spatial Resolution ◽  
Minimum Temperature ◽  
Grid Point ◽  
Temporal Distribution ◽  
Original Data ◽  
Accurate Estimate ◽  
Absolute Temperature ◽  
Data Series ◽  
Absolute Maximum

Abstract. Using the full total of available 5520 observatories covering the whole territory of Spain, a daily gridded maximum and minimum temperature was built covering a period from 1901 to 2014 in peninsular Spain and 1971–2014 in Balearic and Canary Islands. A comprehensive quality control was applied to the original data and the gaps were filled on each day and location independently. Using the filled data series, a grid of 5 × 5 km spatial resolution was created by estimating daily temperatures and their corresponding uncertainties at each grid point. Four daily temperature indices were calculated to describe the spatial distribution of absolute maximum and minimum temperature, number of frost days and number of summer days in Spain. The southern plateau showed the maximum values of maximum absolute temperature and summer days, while the minimum absolute temperature and frost days reached their maximums at northern plateau. The use of all the available information, the complete quality control and the high spatial resolution of the grid allowed for an accurate estimate of temperature that represents a precise spatial and temporal distribution of daily temperatures in Spain. STEAD dataset is publicly available at http://dx.doi.org/10.20350/digitalCSIC/8622.

Coupling Effects on Synchronizability of Two-Layer Network's Projective Outer Synchronization

2017 ◽  
Vol 873 ◽  
pp. 353-357
Author(s):  
Bo Yu Feng ◽  
Zhi Hao Zhang
Keyword(s):  
Nonlinear Dynamics ◽  
Mathematical Model ◽  
Complex Network ◽  
Simulation Experiment ◽  
Small World ◽  
Experimental Results ◽  
Coupling Effects ◽  
Network Synchronization ◽  
Numerical Examples ◽  
Outer Synchronization

Based on nonlinear dynamics theory and knowledge of complex network, this paper expanded the range of two-layer network synchronization to projective outers synchronization. A mathematical model was constructed and feasibility of synchronization was demonstrated. Then we improved the model in order to study the function of different couplings [1]. Numerical examples are examined to compare the synchronizability of projective outer synchronization with different couplings. A rule called "outer small-world effect" was found due to simulation experiment. Finally, some instances were used to explain experimental results.

scholarly journals Reflection of Solar Activity Dynamics in Radionuclide Data

Radiocarbon ◽  
1992 ◽  
Vol 34 (2) ◽  
pp. 207-212 ◽  
Author(s):  
A. V. Blinov ◽  
M. N. Kremliovskij
Keyword(s):  
Nonlinear Dynamics ◽  
Solar Activity ◽  
Numerical Methods ◽  
Chaotic Behavior ◽  
Magnetic Activity ◽  
Data Sets ◽  
Cosmogenic Nuclide ◽  
Proxy Records ◽  
Solar Magnetic Activity ◽  
Activity Dynamics

Variability of solar magnetic activity manifested within sunspot cycles demonstrates features of chaotic behavior. We have analyzed cosmogenic nuclide proxy records for the presence of the solar activity signals. We have applied numerical methods of nonlinear dynamics to the data showing the contribution of the chaotic component. We have also formulated what kind of cosmogenic nuclide data sets are needed for investigations on solar activity.

scholarly journals Persistent Active Longitudes in Sunspot Activity: Sun-as-a-Star Approach

2004 ◽  
Vol 219 ◽  
pp. 128-132
Author(s):  
S. V. Berdyugina ◽  
I. G. Usoskin
Keyword(s):  
Sunspot Group ◽  
Active Regions ◽  
Magnetic Activity ◽  
Sunspot Activity ◽  
Flip Flop ◽  
The Past ◽  
Highly Active ◽  
Group Data ◽  
Cool Stars ◽  
The Mean

Using a new Sun-as-a-star approach we analyze sunspot group data for the past 120 years and reveal that sunspots are formed preferably in two persistent migrating active longitudes 180° apart. Their migration is determined by changes of the mean latitude of sunspots and the surface differential rotation. The two active regions periodically alternate being the dominant region with a period of about 3.7 years similar to the “flip-flop” phenomenon known in starspot activity. The fact that the Sun shows the same pattern of magnetic activity as highly active stars strengthens the solar paradigm for magnetic activity on cool stars.

Lack of genetic evidence for the subspeciation of Pisaster ochraceus (Echinodermata: Asteroidea) in the north-eastern Pacific Ocean

2008 ◽  
Vol 88 (2) ◽  
pp. 395-400 ◽  
Author(s):  
Sarita Frontana-Uribe ◽  
Jorge de la Rosa-Vélez ◽  
Luis Enríquez-Paredes ◽  
Lydia B. Ladah ◽  
Laura Sanvicente-Añorve
Keyword(s):  
Genetic Structure ◽  
Single Species ◽  
Original Data ◽  
Central Position ◽  
Western Coast ◽  
Data Set ◽  
Pisaster Ochraceus ◽  
The North ◽  
Point Conception ◽  
Minimum Spanning Network

The existence of two Pisaster ochraceus subspecies has been proposed; one located northwards (P. ochraceus ochraceus) and the other southwards (Pisaster ochraceus segnis) from Point Conception. We used polymerase chain reaction–restriction fragment length polymorphism of the CO I and CO III mitochondrial genes to assess the degree of population structure from 126 samples collected along the western coast of North America, from Vancouver, Canada to Punta San Carlos, of Baja California, Mexico. The genetic structure was tested through molecular analysis of variance and by Monte Carlo simulations of the original data set. The phylogeographical pattern was deduced from a minimum spanning network analysis. No genetic structure was detected. Instead, a high degree of genetic homogeneity along the species distribution was evident from haplotype frequencies at each location. Two haplotypes, Po1 and Po5, were predominant along the distribution and were considered ancestral because of their central position in the minimum spanning network. Since Pisaster ochraceus depicts a planktotrophic larval stage with very long duration before settlement, it seems to be able to surpass the biogeographical boundary that limits other species around Point Conception, thereby maintaining homogeneity of its genetic pool. Results of this study recognize P. ochraceus as a single species.

scholarly journals National Climate Observing System of Switzerland (GCOS Switzerland)

2011 ◽  
Vol 6 (1) ◽  
pp. 95-102 ◽  
Author(s):  
G. Seiz ◽  
N. Foppa
Keyword(s):  
Land Surface ◽  
Cloud Cover ◽  
Global Climate ◽  
Biological Properties ◽  
Data Series ◽  
Climatological Data ◽  
Mountainous Regions ◽  
The North ◽  
International Data

Abstract. In recent decades, the global observation of climate and climate change has become increasingly important. The Global Climate Observing System (GCOS) established in 1992 addresses the entire climate system including physical, chemical and biological properties of atmosphere, ocean and land surface. This paper describes the GCOS implementation in Switzerland and highlights some major achievements over the last few years. The Swiss GCOS Office was established at the Federal Office of Meteorology and Climatology MeteoSwiss in February 2006, to coordinate all climate-relevant measurements in Switzerland. The first-ever inventory of the country's long-term climatological data series and international data centres, including an assessment of their future prospects, was compiled in 2007. The National Climate Observing System of Switzerland (GCOS Switzerland) includes long-term climatological data series in the atmosphere and terrestrial domains, international data and calibration centres, satellite-based products and support of climate observations in developing countries. A major milestone in the surface-based atmospheric observations was the definition of the Swiss National Basic Climatological Network (NBCN), consisting of 29 stations of greatest climatological importance. The NBCN was further densified for precipitation with 46 additional daily precipitation stations (NBCN-P). Analysis of the homogenized timeseries of the average temperature in Switzerland shows a total warming of +1.6 °C from 1864 to 2010. In the terrestrial domain, substantial advances were made in all three subdomains hydrosphere, cryosphere and biosphere. As example for the use of satellite data within GCOS Switzerland, the 10-yr MODIS monthly mean cloud fraction climatology over Switzerland from March 2000 to February 2010 is presented, which illustrates the differences in cloud cover between mountainous regions and flatland regions in winter, as well as the north-south gradient in cloud cover over Switzerland in summer.

Dynamics of a Rotating System With a Nonlinear Eddy-Current Damper

1998 ◽  
Vol 120 (4) ◽  
pp. 848-853 ◽  
Author(s):  
Y. Kligerman ◽  
O. Gottlieb
Keyword(s):  
Nonlinear Dynamics ◽  
Eddy Current ◽  
Eddy Currents ◽  
Nonlinear Behavior ◽  
Forced Response ◽  
System Response ◽  
Rotating System ◽  
Restoring Force ◽  
Rotating Systems ◽  
Eddy Current Damper

We investigate the nonlinear dynamics and stability of a rotating system with an electromagnetic noncontact eddy-current damper. The damper is modeled by a thin nonmagnetic disk that is translating and rotating with a shaft in an air gap of a direct current electromagnet. The damper dissipates energy of the rotating system lateral vibration through induced eddy-currents. The dynamical system also includes a cubic restoring force representing nonlinear behavior of rubber o-rings supporting the shaft. The equilibrium state of the balanced rotating system with an eddy-current damper becomes unstable via a Hopf bifurcation and exact solutions for the limit cycle radius and frequency of the self-excited oscillation are obtained analytically. Forced vibration induced by the rotating system mass imbalance is also investigated analytically and numerically. System response includes periodic and quasiperiodic solutions. Stability of the periodic solutions obtained from the balanced self-excited motion and the imbalance forced response is analyzed by use of Floquet theory. This analysis enables an explanation of the nonlinear dynamics and stability phenomena documented for rotating systems controlled by electromagnetic eddy-current dampers.

scholarly journals Complexes of activity on the Sun in solar cycle 21

2021 ◽  
pp. 3-9
Author(s):  
Sergey Yazev ◽  
Maria Ulianova ◽  
Elena Isaeva
Keyword(s):  
Solar Activity ◽  
Solar Cycle ◽  
Natural Environment ◽  
Statistical Data ◽  
Sunspot Activity ◽  
The Sun ◽  
Solar Cycles ◽  
The North ◽  
South Asymmetry

The paper provides statistical data on solar activity complexes (ACs) observed in solar cycle 21. From the synoptic charts for the 1976–1986 sunspot activity, we have detected the regions where the sunspot generation was observed at least through three Carrington Rotations (CRs). These regions were identified as AC cores. We have compiled an AC catalogue. ACs are shown to evolve quasi-periodically, in pulses that are 15–20 rotations long. We have analyzed the North-South asymmetry in the AC location. In cycle 21, 90 % of the proton flares that affected the natural environment are shown to have occurred in ACs. We note a tendency for AC activity to decrease, as well as the manifestation of the Gnevyshev—Ohl rule in AC properties, in solar cycles 21–24.

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