000008040 001__ 8040
000008040 005__ 20260227160513.0
000008040 037__ $$aPOSTER-2026-0061
000008040 100__ $$aKalugodu, Chandrashekhar
000008040 245__ $$aReconstruction of the Sunspot Number Series: Gathering Data
000008040 260__ $$c2025
000008040 269__ $$c2025-12-16
000008040 520__ $$aThe Sunspot Number ($S_{N}$) is one of the longest continuous records of solar activity. $S_{N}$ V2.0 significantly improved the historical series through targeted recalibrations, but recent studies have shown that some scale changes—such as the 1849 transition—can only be fully understood by returning to the original raw observations. This motivates a complete reconstruction ($S_{N}$ V3.0) in which uncertainties and calibration steps arise directly from the quality of each dataset rather than from global statistical corrections. To enable this reconstruction, the historical data foundation has expanded dramatically in recent years. WDC–SILSO digitized the Mittheilungen (1610–1944) between 2017 and 2019, converting Wolf’s original Zürich journals into machine-readable datasets with modern metadata and provenance. As part of FARSuN, the Zürich observation tables for 1945–1979 were digitized from 2023 to 2025, completing the recovery of the full Zürich legacy. In parallel, major community efforts (e.g., Hayakawa, Arlt, Vaquero, Carrasco) have located, transcribed, and published numerous additional early telescopic sunspot records since 2010. Together, these datasets greatly expand the number of overlapping observations and allow independent cross-checks across observers and epochs. This richer observational base strengthens scale-transfer analyses, improves calibration robustness, and provides the foundation for an uncertainty-quantified reconstruction of the long-term sunspot series. These advances make a defensible $S_{N}$ V3.0 possible and ensure that the Sunspot Number remains a reliable reference for solar activity studies.
000008040 594__ $$aNO
000008040 6531_ $$aSunspot Number
000008040 6531_ $$aSN V3.0
000008040 6531_ $$aSolar activity reconstruction
000008040 6531_ $$aFARSuN
000008040 6531_ $$aHistorical sunspot observations
000008040 6531_ $$aMittheilungen
000008040 6531_ $$aZürich tables
000008040 6531_ $$aGruithuisen manuscripts
000008040 6531_ $$aAdams sunspot drawings
000008040 6531_ $$aSolar cycle calibration
000008040 6531_ $$aObserver bias
000008040 6531_ $$aScale transfer
000008040 6531_ $$aUncertainty quantification
000008040 6531_ $$aSpace climate
000008040 6531_ $$aSolar-terrestrial relations
000008040 700__ $$aLefèvre, Laure
000008040 700__ $$aMampaey, Benjamin
000008040 700__ $$aValliappan, Senthamizh Pavai
000008040 700__ $$aHayakawa, Hisashi
000008040 700__ $$aRitter, Christian
000008040 773__ $$tAGU Fall Meeting 2025, New Orleans, USA
000008040 8560_ $$fchandrashekhar.kalugodu@ksb-orb.be
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000008040 980__ $$aCPOSTER