Solar activity: nowcasting and forecasting at the SIDC

Berghmans, D.; Linden, R. A. M. Van der; Vanlommel, Petra; Warnant, René; Zhukov, A. N.; Robbrecht, E.; Clette, F.; Podladchikova, O.; Nicula, B.; Hochedez, J.‐F.; Wauters, L.; Willems, Sam

doi:10.5194/angeo-23-3115-2005

Cited by 28 publications

(16 citation statements)

References 38 publications

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“…To keep the consistency and continuity with the data from the Zürich Observatory, they use the Locarno Observatory as the reference station which is one of the major branches of the Zürich Observatory. In 2000, reorganized and expanded by gaining the qualification of Regional Warning Center of the International Space Environment Service, the Sunspot Index Data Center had become the Solar Influences Data analysis Center (SIDC; Berghmans et al 2005). Receiving data monthly from the observing stations throughout the world, the SIDC calculates IRSN, R i , and reports daily, monthly, and annual number of sunspots.…”

Section: Introductionmentioning

confidence: 99%

Relative Sunspot Number Observed from 2002 to 2011 at ButterStar Observatory

Oh¹,

Chang²

2012

Journal of Astronomy and Space Sciences

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The ButterStar Observatory at the Dongducheon High School has been working for photographic observations of the Sun since October 16, 2002. In this study, we observed the Sun at the ButterStar observatory for 3,364 days from October 16, 2002 to December 31, 2011, and analyzed the photographic sunspot data obtained in 1,965 days. The correction factor K b for the entire observing period is 0.9519, which is calculated using the linear least square method to the relationship between the daily sunspot number, R B , and the daily international relative sunspot number, R i . The yearly correction factor calculated for each year varies slightly from year to year and shows a trend to change along the solar cycle. The correction factor is larger during the solar maxima and smaller during the solar minima in general. This implies that the discrepancy between a relative sunspot number, R, and the daily international relative sunspot number, R i , can be reduced by using a yearly correction factor. From 2002 to 2008 in solar cycle 23, 35.4% and 64.6% of sunspot groups and 35.1% and 64.9% of isolated sunspots in average occurred in the northern hemisphere and in the southern hemisphere, respectively, and from 2008 to 2011 in solar cycle 24, 61.3% and 38.7% of sunspot groups and 65.0% and 35.0% of isolated sunspots were observed, respectively. This result shows that the occurrence frequency for each type of sunspot group changes along the solar cycle development, which can be interpreted as the emerging and decaying process of sunspot groups is different depending on the phase of solar cycle. Therefore, it is considered that a following study would contribute to the efforts to understand the dependence of the dynamo mechanism on the phase of solar cycle.

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Section: Introductionmentioning

confidence: 99%

Relative Sunspot Number Observed from 2002 to 2011 at ButterStar Observatory

Oh¹,

Chang²

2012

Journal of Astronomy and Space Sciences

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“…The Uccle Solar Equatorial Table (USET) (http://sidc.be/uset/ usetpres.php), located at the ROB in Brussels, carries four independent refracting telescopes (Berghmans et al 2005 Unit). With these instruments, the aim is to identify and study all events on the Sun that might have implications on the solarterrestrial connection, both through imaging (SWAP) as well as through irradiance measurements (LYRA).…”

Section: Uccle Solar Equatorial Table (Uset) Telescopementioning

confidence: 99%

Multi-instrument observations of the solar eclipse on 20 March 2015 and its effects on the ionosphere over Belgium and Europe

Stankov

Bergeot

Berghmans

et al. 2017

J. Space Weather Space Clim.

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A total solar eclipse occurred on 20 March 2015, with a totality path passing mostly above the North Atlantic Ocean, which resulted in a partial solar eclipse over Belgium and large parts of Europe. In anticipation of this event, a dedicated observational campaign was set up at the Belgian Solar-Terrestrial Centre of Excellence (STCE). The objective was to perform high-quality observations of the eclipse and the associated effects on the geospace environment by utilising the advanced space-and ground-based instrumentation available to the STCE in order to further our understanding of these effects, particularly on the ionosphere. The study highlights the crucial importance of taking into account the eclipse geometry when analysing the ionospheric behaviour during eclipses and interpreting the eclipse effects. A detailed review of the eclipse geometry proves that considering the actual obscuration level and solar zenith angle at ionospheric heights is much more important for the analysis than at the commonly referenced Earth's surface or at the plasmaspheric heights. The eclipse occurred during the recovery phase of a strong geomagnetic storm which certainly had an impact on (some of) the ionospheric characteristics and perhaps caused the omission of some ''low-profile'' effects. However, the analysis of the ionosonde measurements, carried out at unprecedented high rates during the eclipse, suggests the occurrence of travelling ionospheric disturbances (TIDs). Also, the high temporal and spatial resolution measurements proved very important in revealing and estimating some finer details of the delay in the ionospheric reaction and the ionospheric disturbances.

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“…The SIDC (Berghmans et al 2005) collects monthly observations from various stations worldwide in order to calculate the International Relative Sunspot Number R i (Letfus 2000, Clette et al 2007, Vaquero 2007. The center broadcasts the daily, monthly, and yearly sunspot numbers, with middle-range predictions (up to 12 months).…”

Section: Introductionmentioning

confidence: 99%

Does Correction Factor Vary with Solar Cycle?

Chang¹,

Oh²

2012

Journal of Astronomy and Space Sciences

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Monitoring sunspots consistently is the most basic step required to study various aspects of solar activity. To achieve this goal, the observers must regularly calculate their own correction factor k and keep it stable. Relatively recently, two observing teams in South Korea have presented interesting papers which claim that revisions that take the yearly-basis k into account lead to a better agreement with the international relative sunspot number R i , and that yearly k apparently varies with the solar cycle. In this paper, using artificial data sets we have modeled the sunspot numbers as a superposition of random noise and a slowly varying background function, and attempted to investigate whether the variation in the correction factor is coupled with the solar cycle. Regardless of the statistical distributions of the random noise, we have found the correction factor increases as sunspot numbers increase, as claimed in the reports mentioned above. The degree of dependence of correction factor k on the sunspot number is subject to the signal-to-noise ratio. Therefore, we conclude that apparent dependence of the value of the correction factor k on the phase of the solar cycle is not due to a physical property, but a statistical property of the data.

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Solar activity: nowcasting and forecasting at the SIDC

Cited by 28 publications

References 38 publications

Relative Sunspot Number Observed from 2002 to 2011 at ButterStar Observatory

Relative Sunspot Number Observed from 2002 to 2011 at ButterStar Observatory

Multi-instrument observations of the solar eclipse on 20 March 2015 and its effects on the ionosphere over Belgium and Europe

Does Correction Factor Vary with Solar Cycle?

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