861 research outputs found

    Comparison of Ground- and Space-based Longitudinal Magnetograms

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    We compare photospheric line-of-sight magnetograms from the Synoptic Long-term Investigations of the Sun (SOLIS) vector spectromagnetograph (VSM) instrument with observations from the 150-foot Solar Tower at Mt. Wilson (MWO), Helioseismic and Magnetic Imager (HMI) on Solar Dynamics Observatory (SDO), and Michelson Doppler Imager (MDI) on Solar and Heliospheric Observatory (SOHO). We find very good agreement between VSM and the other data sources for both disk-averaged flux densities and pixel-by-pixel measurements. We show that the VSM mean flux density time series is of consistently high signal-to-noise with no significant zero-offsets. We discuss in detail some of the factors -spatial resolution, flux dependence and position on the solar disk- affecting the determination of scaling between VSM and SOHO/MDI or SDO/HMI magnetograms. The VSM flux densities agree well with spatially smoothed data from MDI and HMI, although the scaling factors show clear dependence on flux density. The factor to convert VSM to HMI increases with increasing flux density (from \approx1 to \approx1.5). The nonlinearity is smaller for the VSM vs. ~SOHO/MDI scaling factor (from \approx1 to \approx1.2).Comment: Accepted for publication in Solar Physic

    Correlation Between Sunspot Number and ca II K Emission Index

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    Long-term synoptic observations in the resonance line of Ca II K constitute a fundamental database for a variety of retrospective analyses of the state of the solar magnetism. Synoptic Ca II K observations began in late 1904 at the Kodaikanal Observatory, in India. In early 1970s, the National Solar Observatory (NSO) at Sacramento Peak (USA) started a new program of daily Sun-as-a-star observations in the Ca II K line. Today the NSO is continuing these observations through its Synoptic Optical Long-term Investigations of the Sun (SOLIS) facility. These different data sets can be combined into a single disk-integrated Ca II K index time series that describes the average properties of the chromospheric emission over several solar cycles. We present such a Ca II K composite and discuss its correlation with the new entirely revised sunspot number data series. For this preliminary investigation, the scaling factor between pairs of time series was determined assuming a simple linear model for the relationship between the monthly mean values during the duration of overlapping observations.Comment: 16 pages, 8 figures, accepted for publication in Solar Physic

    Fiscal Situation and Stabilization Fund of Buenos Aires City: evolution and forecast

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    After a period of positive fiscal results during years 2003 to 2005, the City of Buenos Aires faces challenges in its fiscal situation as of year 2006, which surely will be reflected in exercise 2007. During the period the 2003- 2005 City accumulated positive financial results near 1,800million,startsoffofwhich,1,800 million, starts off of which, 418 million, they were destined to the Stabilization Fund created in 2003 by Decree of the Executive authority. The estimations made by the Executive authority on the closing of exercise 2006 at the time of presenting the Project of Budget 2007 show a negative result of -$1,096 million, the contained negative result in Budget 2007 bases similar originally elevated by the Executive to the Legislature, and later modified in the parliamentary approval. As opposed to an electoral year, where the pressures on the public expenditure usually increase, it is precise to strengthening the institutionalization and transparency of the Buenos Aires City Stabilization Fund.Fiscal Policy-Stabilization Fund-Budget Process-Legislature

    Interpretation of Solar Magnetic Field Strength Observations

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    This study based on longitudinal Zeeman effect magnetograms and spectral line scans investigates the dependence of solar surface magnetic fields on the spectral line used and the way the line is sampled in order to estimate the magnetic flux emerging above the solar atmosphere and penetrating to the corona from magnetograms of the Mt. Wilson 150-foot tower synoptic program (MWO). We have compared the synoptic program \lambda5250\AA line of Fe I to the line of Fe I at \lambda5233\AA since this latter line has a broad shape with a profile that is nearly linear over a large portion of its wings. The present study uses five pairs of sampling points on the λ5233\lambda5233\AA line. We recommend adoption of the field determined with a line bisector method with a sampling point as close as possible to the line core as the best estimate of the emergent photospheric flux. The combination of the line profile measurements and the cross-correlation of fields measured simultaneously with \lambda5250\AA and \lambda5233\AA yields a formula for the scale factor 1/\delta that multiplies the MWO synoptic magnetic fields. The new calibration shows that magnetic fields measured by the MDI system on the SOHO spacecraft are equal to 0.619+/-0.018 times the true value at a center-to-limb position 30 deg. Berger and Lites (2003) found this factor to be 0.64+/-0.013 based on a comparison the the Advanced Stokes Polarimeter.Comment: Accepted by Solar Physic

    Random Lag Singular Cross-Spectrum Analysis

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    In a previous paper (Varadi et al., 1999), Random Lag Singular Spectrum Analysis was offered as a tool to find oscillations in very noisy and long time series. This work presents a generalization of the technique to search for common oscillations in two or more time series.Comment: 8 pages + 1 figure (eps), Macro: AASTe
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