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Dear Colleagues,</div>
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We are organizing the COSPAR International Reference Atmosphere (CIRA) session at the 46th COSPAR Scientific Assembly in Florence, Italy, from 1-9 August 2026. The session covers all aspects of thermosphere modeling and forecasting, including drivers, drag
and aerodynamic coefficients, observations, and data assimilation:</div>
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C4.2: Development of First-Principles and Empirical Models Related to the COSPAR International Reference Atmosphere</div>
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<i>This event will consider the development and assessment of atmospheric models, both first-principles and empirical, for the COSPAR International Reference Atmosphere (CIRA). This session solicits presentations on recent advances in thermosphere, coupled
upper atmosphere, and Whole Atmosphere Modeling and recommendations for future research and development, especially in the context of addressing satellite drag. Talks related to issues of applying first-principles models, or reduced-order models, to operational
problems are welcomed. Descriptions of models with the potential of future operational transition are especially encouraged. Model construction and validation is limited by the availability of data. Description of the (re)processing of old and new data, i.e.
neutral density, composition, and temperature measurements, for use in upper atmosphere model construction/validation will also be discussed, including the model drivers (e.g., F10.7, F30, Kp, Hp, Dst, etc) and their uncertainty and stability. It also includes
near-real time assimilation efforts and any associated validation of the estimated thermospheric states.</i></div>
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Abstract submission closes on February 13th.</div>
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Thank you and best regards,</div>
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Sean Bruinsma and Marcin Pilinski</div>
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CIRA Session Link:</div>
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<a href="https://cedarscience.org/cedar-post-newsletter">https://cedarscience.org/cedar-post-newsletter</a></div>
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The Assembly web page address is:</div>
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<u><a style="margin: 0px;" data-linkindex="0" data-auth="NotApplicable" originalsrc="https://www.cospar-assembly.org/" rel="noopener noreferrer" title="Original URL: https://www.cospar-assembly.org/. Click or tap if you trust this link." class="x_x_x_x_x_x_x_x_OWAAutoLink" id="OWAaf7d609b-de6d-fecb-dc40-af2b7506c3de" target="_blank" href="https://www.cospar-assembly.org/">https://www.cospar-assembly.org</a></u></div>
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The Call for Abstracts may be found at:</div>
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<u><a style="margin: 0px;" data-linkindex="1" data-auth="NotApplicable" originalsrc="https://issuu.com/jccospar/docs/call_for_abstracts_2026?fr=sMzY4Njg3MzM2Njg" rel="noopener noreferrer" title="Original URL: https://issuu.com/jccospar/docs/call_for_abstracts_2026?fr=sMzY4Njg3MzM2Njg. Click or tap if you trust this link." class="x_x_x_x_x_x_x_x_OWAAutoLink" id="OWA97e7e7bd-2a9d-ddd6-198f-10924f47b291" target="_blank" href="https://issuu.com/jccospar/docs/call_for_abstracts_2026?fr=sMzY4Njg3MzM2Njg">https://issuu.com/jccospar/docs/call_for_abstracts_2026?fr=sMzY4Njg3MzM2Njg</a></u></div>
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Marcin Pilinski</div>
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Research Associate</div>
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Laboratory for Atmospheric and Space Physics</div>
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University of Colorado</div>
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3665 Discovery Dr.</div>
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Boulder, CO 80303</div>
<div style="margin: 0px;" class="elementToProof"><span style="font-family: Calibri, Arial, Helvetica, sans-serif;">Phone
</span><span style="font-family: "Trebuchet MS", Helvetica, Arial, sans-serif; font-size: 14.4px; background-color: rgb(255, 255, 255);">303-735-7680</span></div>
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