Towards an Early Warning System for Arctic Freshwater-Driven Tipping Points in the Greenland Ice Sheet and North Atlantic Subpolar Gyre with AEROSTATS

The climate system is approaching dangerous tipping points, with the potential collapse within decades of critical components such as the Greenland Ice Sheet and the North Atlantic Subpolar Gyre posing severe risks to European weather and global climate stability. Changes in Arctic freshwater, driven by changes in ice-sheet and sea-ice melt and atmosphere-ocean-ice interactions, play a central role in these risks by influencing ocean stratification, deep water formation and air-sea fluxes. Despite the urgent need for early warnings, major gaps remain between existing observations and the data required to constrain predictive models, limiting confidence in future projections.Earth-orbiting satellites and in situ observations provide essential information on large-scale ocean, cryosphere, and atmosphere change, but they struggle to capture fast processes at kilometre and sub-kilometre scales in complex regions such as marginal ice zones. A different type of observations is needed to quantify the role of these processes in exchanges of freshwater, heat, and momentum that the Arctic and the Greenland Ice Sheet to the North Atlantic Subpolar Gyre.This paper will introduce AEROSTATS (Aerial Experimental Remote sensing of Ocean Salinity, heaT, Advection, and Thermohaline Shifts), a UK-led international project designed to demonstrate a new approach to long-term, low-cost, low-carbon monitoring of Arctic freshwater processes in Greenland’s dynamic ocean–ice margins. AEROSTATS focuses on innovative airborne platforms capable of remote, high-resolution imaging of total surface current vectors, near-surface winds, sea surface salinity, ocean colour, and sea surface temperature at 1-10km and sub-daily scales.Funded as a high-risk, forward-looking project, AEROSTATS seeks to collect and integrate data from new airborne instruments, in situ surface and subsurface platforms, spaceborne sensors, and high-resolution reanalyses and models. A core element is a 2028 year-round field campaign in the Greenland/Subpolar Gyre region deploying airborne systems to observe freshwater-driven processes across seasons. By combining multi-platform observations with models and reanalyses using digital tools such as machine learning and digital twins, AEROSTATS aims to establish new long-term monitoring capability to substantially improve early warning for freshwater-related tipping points.