teleconnection

Teleconnection is a term in climatology describing climate anomalies that are related across long distances, often thousands of kilometers apart, due to large-scale atmospheric and oceanic processes. Teleconnections manifest as coherent patterns of anomalous temperature, precipitation, or pressure in widely separated regions, typically in response to a common forcing in another region. They arise through atmospheric circulation patterns such as Rossby wave trains and through coupled ocean-atmosphere dynamics that propagate anomalies from the tropics to higher latitudes or between ocean basins.

Well-known examples include El Niño-Southern Oscillation (ENSO), which links tropical Pacific sea surface temperature anomalies to weather pattern changes around the world, affecting North American winter storms, Asian monsoon variability, and rainfall in Africa and South America. Northern Hemisphere winter teleconnections include the North Atlantic Oscillation (NAO) and the Pacific-North American (PNA) pattern, which modulate weather in Europe and North America. The Arctic Oscillation (AO) also influences winter conditions in the extratropics. Other regional teleconnections involve the Indian Ocean Dipole and, on shorter timescales, the Madden-Julian Oscillation driving tropical-extratropical connections.

Detection and significance: teleconnections are identified through statistical analyses of climate data, such as correlations, composites, empirical orthogonal functions (EOFs), and maximum covariance analysis, and are reproduced in climate models. They help explain how local climate anomalies relate to distant forcings and why regional weather and climate variability can be influenced by distant climate states.