Scientists use modes of decadal variability to describe patterns in the climate system that occur over longer periods of time than weather patterns. These modes do not operate on regular time intervals because they are designed to capture statistical patterns happening across a range of time scales from interannual to multidecadal. In the tropical Pacific and associated climate system, there are a number of Pacific decadal-scale variability (PDV) modes which affect biogeochemical cycles, marine ecosystems, weather, and climate extremes like droughts and marine heat waves. The dominant modes in the Pacific basin are reviewed in a recent scientific paper supported in part by the Climate Program Office’s Climate Variability & Predictability (CVP) Program.
An international team of researchers, including CVP-funded scientist Antonietta Capotondi of NOAA’s Physical Sciences Laboratory, builds upon their previous work focused on predictability of PDV modes and provides a synthesis of our current understanding of the fundamental mechanisms driving these modes of variability. The team draws connections between tropical processes and the middle latitudes beyond the tropics, as well as outlines a dynamical modeling approach to help distinguish PDV modes and understand specific drivers. The review, published in the Annual Review of Marine Science, offers a modified paradigm of the connections between modes and how air-sea interactions across the Pacific Ocean basin may produce the observed variability. This work deepens our understanding of climate variability, going beyond statistical descriptions. CVP funded this project to improve predictability and understanding of decadal climate variability, as this time scale is challenging yet essential for long-term planning and mitigation.