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We invite you to submit an abstract to Session SH031, The Future of the International Sunspot Number, at the Fall 2025 AGU Meeting.</p>
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The AGU meeting will be held 15-19 Dec 2025 in New Orleans, LA.</p>
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<b>The abstract deadline is Wednesday, 30 July 2025 23:59 ET/03:59 UTC</b></p>
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Our session is described at: https://agu.confex.com/agu/agu25/prelim.cgi/Session/250850</p>
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The international sunspot number (SN) is the recalibration of the Zürich sunspot number (RZ) that is currently measured and served at the WDC SILSO. This modernization provides a consistent extension of the most analyzed solar-variability observational time
series available. After the recalibration that culminated in 2015, the current reconstruction includes a re-examination of the sources underlying SN and means of connecting different observational records. The working group responsible for SN is accumulating
original drawings and searching for sources of data particularly during the various temporal gaps in coverage. This research improves the historical record especially before 1825. </p>
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The goal of this session is to focus on ways to continue updating the observer-record calibrations and the temporal coverage of SN, and to assess future needs. This covers a wide range of subjects such as: Should the cadence of the released data be increased,
such as from the current one day to one hour? Can AI/ML algorithms ingest the hand-drawn images from the 1600s to the 1800s and help fill in gaps? Works describing how SN can be improved to match the user needs or ways to implement SN in modern algorithms
are solicited. </p>
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Feel free to contact us at <a href="mailto:SDO2025sw@gmail.com">SDO2025sw@gmail.com</a> with any questions or concerns.</p>
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We are looking forward to seeing your abstract!</p>
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Sincerely, The Session SH031 Conveners</p>
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Dean Pesnell; Greg Kopp; Laure Lefèvre, and Theodosios Chatzistergos</p>
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