Submesoscale density fronts, spanning horizontal scales of 0.2–20 km, play a crucial role in mediating cross-scale energy transfers and tracer transports in the global ocean. The strength of these fronts is jointly controlled by temperature and salinity gradients, which often vary in a compensatory manner-a phenomenon known as density compensation. Previous studies have largely focused on the density compensation at salinity-dominated submesoscale fronts in river-influenced regions. However, in most of the open ocean, density is temperature-dominated, and density compensation in such regimes remains poorly understood. Here, using year-long mooring observations and idealized numerical simulations, we show that the extent of density compensation is much stronger at submesoscales than at mesoscales (20–300 km) in a typical open-ocean region. In frontal regions characterized by strong thermohaline gradients, approximately 10% of temperature gradients are fully compensated by salinity gradients at submesoscales. We further demonstrate that atmospheric cooling effectively weakens horizontal temperature gradients during submesoscale restratification but exerts minimal impact on salinity, thereby facilitating full density compensation at temperature-dominated submesoscale fronts. These findings reveal surface cooling as a damper of density fronts and available potential energy at submesoscales, and highlight the need to quantify its prevalence and impact on energetics across the global ocean.

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