Scientific Program Overview: Troposphere High latitude INhibitors to multi-scale sea ICE Predictability (THINICE)

This is an award to support continued planning for THINICE. It is not a commitment by NSF to fund the field project and related analysis and numerical simulation work. Those funding decisions will be determined by means of further review. In recent decades, the Arctic has transitioned to more mobile and thinner sea ice and more expansive stretches of open ocean. One outcome of these profound changes is the increasingly important role of Arctic Cyclones (ACs) in the loss of sea ice, which can occur at an astonishing rate of 1/2 million km2 within a 3-day period, an area that is bigger than California and approximately the size of Spain. An accurate prediction of such sea ice losses and the interplay between Arctic cyclones, sea ice and the open ocean is becoming increasing important for public safety, commerce, and national security. Unfortunately, the accurate prediction of ACs and sea ice loss is often a challenge, even on weather time-scales. This award supports continued planning for the THINICE to address this challenge. The sampling plan will include a 6-week international, multi-agency field campaign for July and August 2021 with a complementary numerical modeling and analysis component. This SPO is to organize the first systematic observational investigation to enhance our understanding of the critical mechanisms that determine the location, strength, evolution, and characteristics of TPVs, ACs and their potential for influencing sea ice break-up and decline. THINICE will directly contribute to NSF's goal of 'Navigating the New Arctic', which is one of the agencies ten bold ideas for future investment at the frontiers of science and engineering. THINICE will also contribute to NSF INCLUDES (Inclusion across the Nation of Communities of Learners of Underrepresented Discoverers in Engineering and Science) through educational and outreach activities that utilize NSF's Research Experience for Undergraduates program to involving indigenous students, including through novel social media efforts. Fundamental differences exist between the dynamics of cyclones in middle latitude and the Arctic as, for example, the higher planetary rotation rate in the Arctic means that vortices will play more significant role in the cyclogenesis process. In particular, Tropopause Polar Vortices (TPVs) serve as an important precursor to the formation of ACs with cyclogenesis taking place when these vortices interact with low-level baroclinic zones. Another difference between weather systems in the Arctic and middle latitudes is the increased importance at higher latitudes of radiative processes relative to latent heating. Thus, the treatment of cloud and radiative processes is likely critical to accurately defining the structure and intensity of TPVs and ACs. While major field campaigns have been launched to study cyclones in middle latitudes, detailed observational studies of TPVs and ACs have not yet been undertaken. The THINICE SPO will coordinate efforts with plans to utilize in-situ and remote sensing measurements taken from the NSF-NCAR GV research aircraft to advance our knowledge of: (1) The dynamical and physical processes that control the intensity, structure, and evolution of ACs and TPVs; (2) The dynamical interactions between TPVs and ACs, including the role of TPVs in cyclogenesis and how ACs are modified when multiple TPVs are interactive; and (3) The coupling of TPVs and ACs with the underlying sea surface and sea ice during the summer, and how such coupling can lead to rapid sea ice loss and feedbacks that might, in turn, modify TPVs and ACs.