<div dir="ltr"><div><span style="color:rgb(14,16,26);font-family:"Times New Roman",Times,serif;font-size:16px"><b>From Geoff Crowley:</b></span><span style="font-family:"Times New Roman",Times,serif;font-size:12pt;color:rgb(0,0,0)"><br></span></div><span style="font-family:"Times New Roman",Times,serif;font-size:12pt;color:rgb(0,0,0)"><div><span style="font-family:"Times New Roman",Times,serif;font-size:12pt;color:rgb(0,0,0)"><br></span></div>Dear Colleagues,   </span><div style="direction:ltr"><span style="font-family:"Times New Roman",Times,serif;font-size:12pt;color:rgb(0,0,0)">I wanted to let you all know that the abstract submission</span><span style="font-family:"Times New Roman",Times,serif;font-size:12pt;color:rgb(0,0,0)"> deadline </span><span style="font-family:"Times New Roman",Times,serif;font-size:12pt;color:rgb(0,0,0)">for the URSI meeting in the </span><span style="font-family:"Times New Roman",Times,serif;font-size:12pt;color:rgb(0,0,0)">Canary Islands </span><span style="font-family:"Times New Roman",Times,serif;font-size:12pt;color:rgb(0,0,0)">has been extended to February 1st.</span></div><div style="direction:ltr"><span style="font-family:"Times New Roman",Times,serif;font-size:12pt;color:rgb(0,0,0)"><br></span></div><div style="direction:ltr"><span style="font-family:"Times New Roman",Times,serif;font-size:12pt;color:rgb(0,0,0)">The </span><span style="font-family:"Times New Roman",Times,serif;font-size:12pt;color:rgb(0,0,0)">Extended Abstract (or Summary paper)</span><span style="font-family:"Times New Roman",Times,serif;font-size:12pt;color:rgb(0,0,0)"> submission site is at: </span></div><div style="direction:ltr"><span style="font-family:"Times New Roman",Times,serif;font-size:12pt;color:rgb(0,0,0)"><a href="https://www.atrasc.com/papersubmission.php" id="m_45599121079698357OWAac86a6ff-0b37-9994-7cac-4cb36b683d2e" target="_blank">https://www.atrasc.com/papersubmission.php</a></span></div><div style="direction:ltr"><span style="font-family:"Times New Roman",Times,serif;font-size:12pt;color:rgb(0,0,0)"><br></span></div><p style="direction:ltr;margin:0cm 0cm 0.0001pt"><span style="font-family:"Times New Roman",Times,serif;font-size:12pt;color:rgb(14,16,26)">On behalf of the URSI AT-RASC, Session G02 conveners, I am delighted to bring to your attention </span><span style="font-family:"Times New Roman",Times,serif;font-size:12pt;color:rgb(5,99,193)"><b><u><a href="https://www.atrasc.com/papersubmission.php#G" id="m_45599121079698357OWA4905ee79-a274-5e47-35c7-ab8543b3871b" target="_blank" style="color:rgb(5,99,193);margin:0px">session G02</a></u></b></span><span style="font-family:"Times New Roman",Times,serif;font-size:12pt;color:rgb(36,36,36)">:</span><span style="font-family:"Times New Roman",Times,serif;font-size:12pt;color:rgb(14,16,26)">: Nowcasting and Forecasting Travelling Ionospheric Disturbances for Ionospheric Weather and Mitigation Services (see session abstract below).</span></p><p style="direction:ltr;margin:0cm 0cm 0.0001pt"><span style="font-family:"Times New Roman",Times,serif;font-size:12pt;color:rgb(14,16,26)">Please visit the </span><span style="font-family:"Times New Roman",Times,serif;font-size:12pt;color:rgb(74,110,224)"><u><a href="https://www.atrasc.com/home.php" id="m_45599121079698357OWA659de5b6-439a-709d-85b6-7a414ab9912a" target="_blank" style="color:rgb(74,110,224);margin:0px">conference website</a></u></span><span style="font-family:"Times New Roman",Times,serif;font-size:12pt;color:rgb(14,16,26)"> and submit your Extended Abstract (or Summary paper) to our session by<b> February 1st, 2024 at 4.59pm Eastern (2.59pm Mountain)</b></span></p><p style="direction:ltr;margin:0cm 0cm 0.0001pt"><span style="font-family:"Times New Roman",Times,serif;font-size:12pt;color:rgb(14,16,26)"> </span></p><p style="direction:ltr;margin:0cm 0cm 0.0001pt"><span style="font-family:"Times New Roman",Times,serif;font-size:12pt;color:rgb(14,16,26)"> </span></p><p style="direction:ltr;margin:0cm 0cm 0.0001pt"><span style="font-family:"Times New Roman",Times,serif;font-size:12pt;color:rgb(14,16,26)">Conveners: Geoff Crowley, David Altadill, Anna Belehaki, Sivakandan Mani</span></p><p style="direction:ltr;margin:0cm 0cm 0.0001pt"><span style="font-family:"Times New Roman",Times,serif;font-size:12pt;color:rgb(14,16,26)"> </span></p><p style="direction:ltr;margin:0cm 0cm 0.0001pt"><span style="font-family:"Times New Roman",Times,serif;font-size:12pt;color:rgb(14,16,26)"><b>Abstract</b>: Travelling Ionospheric Disturbances (TIDs) are plasma density fluctuations that propagate as waves through the ionosphere at a wide range of velocities and frequencies and play an important role in the exchange of momentum and energy between various regions of the upper atmosphere. TIDs are the ionospheric manifestation of internal atmospheric gravity waves (AGW) in the neutral atmosphere and are associated with auroral and geomagnetic activity and with lower atmosphere phenomena of non-space origin (e.g., severe tropospheric convection or passages of cold fronts, seismicity, volcanic activity, and artificially triggered events such as explosions). The exact physical mechanisms of TIDs formation, the trigger mechanisms, the basic properties and parameters of TIDs and their propagation direction from the source, how they dissipate with distance and how background ionospheric conditions affect their propagation, have still not been fully characterized or understood. Nevertheless, it is confirmed that TIDs constitute a threat for operational systems that use simple predictions of ionospheric characteristics and especially in ground-based and aerospace applications.</span></p><p style="direction:ltr;margin:0cm 0cm 0.0001pt"><span style="font-family:"Times New Roman",Times,serif;font-size:12pt;color:rgb(14,16,26)"> The session invites contributions on TIDs identification and tracking experiments and methodologies, on models for nowcasting and forecasting TIDs and corresponding ionospheric weather services, descriptions of operational issues caused by TIDs, and possible mitigation technologies able to prevent degradation of the applications concerned.</span></p><p style="direction:ltr;margin:0cm 0cm 0.0001pt"><span style="font-family:"Times New Roman",Times,serif;font-size:12pt;color:rgb(14,16,26)"> </span></p><p style="direction:ltr;margin:0cm 0cm 0.0001pt"><span style="font-family:"Times New Roman",Times,serif;font-size:12pt;color:rgb(14,16,26)">Thank you.</span></p><p style="direction:ltr;margin:0cm 0cm 0.0001pt"><span style="font-family:"Times New Roman",Times,serif;font-size:12pt;color:rgb(14,16,26)">With best regards </span></p><p style="direction:ltr;margin:0cm 0cm 0.0001pt"><span style="font-family:"Times New Roman",Times,serif;font-size:12pt;color:rgb(14,16,26)"><br></span></p><p style="direction:ltr;margin:0cm 0cm 0.0001pt"><span style="font-family:"Times New Roman",Times,serif;font-size:12pt;color:rgb(14,16,26)"><br>Geoff</span></p><p style="direction:ltr;margin:0cm 0cm 0.0001pt"><span style="font-family:"Times New Roman",Times,serif;font-size:12pt;color:rgb(14,16,26)"><br></span></p><p style="direction:ltr;margin:0cm 0cm 0.0001pt"><span style="font-family:"Times New Roman",Times,serif;font-size:12pt;color:rgb(14,16,26)">Geoff Crowley</span></p><p style="direction:ltr;margin:0cm 0cm 0.0001pt"><span style="font-family:"Times New Roman",Times,serif;font-size:12pt;color:rgb(14,16,26)">Orion Space Solutions </span></p><p style="direction:ltr;margin:0cm 0cm 0.0001pt"><span style="font-family:"Times New Roman",Times,serif;font-size:12pt;color:rgb(14,16,26)">(an Arcfield company)</span></p><p style="direction:ltr;margin:0cm 0cm 0.0001pt"><span style="font-family:"Times New Roman",Times,serif;font-size:12pt;color:rgb(14,16,26)">210-834-3475</span></p></div>