Winter Targeted Observing Periods during the Year of Polar Prediction in the Southern Hemisphere (YOPP-SH)

Abstract

The Year of Polar Prediction in the Southern Hemisphere (YOPP-SH) held seven TargetedObserving Periods (TOPs) during the 2022 austral winter to enhance atmospheric predictabilityover the Southern Ocean and Antarctica. The TOPs of 5-10 days duration each featured therelease of additional radiosonde balloons, more than doubling the routine sounding program atthe 24 participating stations run by 14 nations, together with process-oriented observations atselected sites. These extra sounding data are evaluated for their impact on forecast skill via datadenial experiments with the goal of refining the observing system to improve numerical weatherprediction for winter conditions. Extensive observations focusing on clouds and precipitationprimarily during atmospheric river (AR) events are being applied to refine model microphysicalparameterizations for the ubiquitous mixed phase clouds that frequently impact coastalAntarctica. Process studies are being facilitated by high time resolution series of observationsand forecast model output via the YOPP Model Intercomparison and Improvement Project(YOPPsiteMIIP). Parallel investigations are broadening the scope and impact of the YOPP-SHwinter TOPs. Studies of the Antarctic tourist industry’s use of weather services show the scopefor much greater awareness of the availability of forecast products and the skill they exhibit. TheSIPN South analysis of predictions of the sea ice growth period reveals that the forecast skill issuperior to the sea ice retreat phase.