In a new paper published in the Journal of Climate, CPO’s Climate Observations and Monitoring (COM) Program-funded scientist Cameron Lee presents two new climate indicators that show changes in weather conditions over time based on multiple variables: a Warm/Cool Index and a Global Extremes Index.
Recent research efforts have developed a global-scale classification scheme to categorize large-scale weather types based on surface weather conditions. These advances allow examination of long-term trends and short-term variability of multiple surface weather conditions over a 40 year period. Both of the new indicators have increased significantly over time since 1979 and show a moderate to strong connection with the global temperature record. The Warm/Cool Index is strongly related to the Atlantic Multidecadal Oscillation (AMO), showing that AMO greatly impacts variability of multiple near-surface weather conditions. The Global Extremes Index is strongly related to the El Nino Southern Oscillation (ENSO), highlighting the established impact ENSO has on extreme events. Researchers highlight the significance of examining trends in large-scale weather patterns using these indicators, since these reflect near surface conditions, are key drivers of extra-tropical weather, and are important regulators of human comfort for approximately half of the world’s population.