Western boundary currents influence local climate, new research claims

A study led by atmospheric scientists at Colorado State University shows that western boundary currents, powerful ocean currents along coastlines, have a greater impact on local climate variability than previously recognized. Researchers James Larson, David Thompson and James Hurrell shared their findings in Nature. They showed how these currents affect temperature and atmospheric patterns in ways that can refine climate models and improve weather forecasts.

Western boundary currents, including the Gulf Stream off the coast of North America and the Kuroshio Current near Japan, are known for transporting large volumes of warm water from tropical regions to higher latitudes. This movement affects winds, precipitation, and general climate patterns over vast areas. But the research goes deeper. It specifically examines how these currents influence local weather variations, rather than just broader climate averages.

High-resolution data shows links between the ocean and the atmosphere

The researchpublished on Phys.org, reveals that using high-resolution satellite data and numerical models, the team investigated how changes in sea surface temperatures (SSTs) over western boundary currents correlate with atmospheric circulation and precipitation. Their monthly analysis tracked how SST variations are related to shifts in air circulation in the lower atmosphere, especially around these major currents. They found that fluctuations in SSTs directly influence atmospheric behavior, such as vertical air movement and rainfall patterns.

For example, regions with larger SST changes relative to western boundary currents also showed significant shifts in local atmospheric circulation and precipitation. This find indicates that these currents not only carry warm water, but also drive complex weather dynamics in nearby areas, creating variability in rainfall and atmospheric conditions that can affect local climate in both hemispheres.

Implications for climate models and forecasts

The insights from the study suggest that existing weather and climate models may need to be adjusted to account for the influence of these currents on local climate variability. Larson and his team highlight a mechanism by which ocean conditions influence the atmosphere in ways not yet fully captured by current forecast models.

By demonstrating the close link between SSTs over boundary currents and local weather patterns, the researchers’ work could lead to more accurate forecasts for regions affected by these oceanic pathways. With improved modeling, communities near major boundary currents could benefit from better predictions of weather changes due to ocean temperatures.