A time series of GONG Dopplergrams for the period 10-14 May 1997 from Udaipur and Big Bear sites has been used to measure the velocity fluctuations in the sunspot (NOAA active region 8038) and quiet photosphere simultaneously. We observe that the power of pre-dominant p-mode is reduced in the sunspot as compared to quiet photosphere by 39-52% depending on the location of the sunspot region on t...

We analyze the widely used international/Zürich sunspot number record, R, with a view to quantifying a suspected calibration discontinuity around 1945 (which has been termed the “Waldmeier discontinuity”). We compare R against the composite sunspot group data from the Royal Greenwich Observatory network and the Solar Optical Observing Network, using both the number of sunspot groups, NG, and th...

The continuous emission spectra of Hα, Hβ, and Hγ wave bands of the solar flare of 5 July 1989 have been analysed. We demonstrate that the flare not only emits at the line centres and wings of Hα, Hβ, and Hγ, but also in the continuum near these lines. The positions, durations, and configurations of the four flare kernels are respectively similar to those of a white light flare (WLF). Therefore...

We analyze sunspot-equilibrium prices in nonconvex economies with perfect markets and a continuous sunspot variable. Our primary result is that every sunspot equilibrium allocation can be supported by prices that, when adjusted for probabilities, are constant across states. This result extends to the case of a finite number of equally probable states under weak nonsatiation conditions, but does...

OBJECTIVE The cause precipitating intracranial aneurysm rupture remains unknown in many cases. It has been observed that aneurysm ruptures are clustered in time, but the trigger mechanism remains obscure. Because solar activity has been associated with cardiovascular mortality and morbidity, we decided to study its association to aneurysm rupture in the Swiss population. METHODS Patient data ...

Because of the lack of reliable sunspot observation, the quality of sunspot number series is poor in the late 18th century, leading to the abnormally long solar cycle (1784–1799) before the Dalton minimum. Using the newly recovered solar drawings by the 18–19th century observers Staudacher and Hamilton, we construct the solar butterfly diagram, i.e. the latitudinal distribution of sunspots in t...

In this paper, a machine learning-based system that could provide automated short-term solar flares prediction is presented. This system accepts two sets of inputs: McIntosh classification of sunspot groups and solar cycle data. In order to establish a correlation between solar flares and sunspot groups, the system explores the publicly available solar catalogues from the National Geophysical D...

Yearly averages of geomagnetic activity indices Ap for the years 1967±1984 are compared to the respective averages of m Bs, where v is the solar wind velocity and Bs is the southward interplanetary magnetic ®eld (IMF) component. The correlation of both quantities is known to be rather good. Comparing the averages of Ap with m and Bs separately we ®nd that, during the declining phase of the sola...

We use 130 years data for studying correlative effects due to solar cycle and activity phenomena on the occurrence of the Indian Monsoon rainfall. We compute the correlation coefficients and significance of correlation coefficients for the seasonal and the annual data. We find that: (i) for the whole years 1871–2000, the spring and southwest monsoon rainfall variabilities have significant posit...

The uncombed penumbral model explains the structure of the sunspot penumbra in terms of thick magnetic fibrils embedded in a magnetic surrounding atmosphere. This model has been successfully applied to explain the polarization signals emerging from the sunspot penumbra. Thick penumbral fibrils face some physical problems, however. In this contribution we will offer possible solutions to these s...