Doubling the Length of Southern Hemispheric Annular Mode (SAM) Reconstructions Clarifies Roles of Human and Natural Impacts on Climate


The Southern Hemisphere Annular Mode (SAM) is a southern hemisphere-wide pattern of climate variability that influences diverse aspects of climate from temperature and precipitation to oceanic and sea-ice circulation. A study co-authored by DOE scientist Phil Jones, has extended our ability to look at SAM trends to a century from previous limitations to analysis from 1948/58-present. This work indicates that recent trends in SAM are affected both by human activities and natural forcing factors in the climate system. In addition to contributing to the understanding of past climate in the Southern Hemisphere, this study improves the accuracy of climate simulations, and provides a long-term benchmark for future modeling efforts, important for DOE’s need to plan for and predict the impacts of future energy options.


Jones, J.M., Fogt, R.L., Widmann, M., Marshall, G., Jones, P.D. and Visbeck, M., 2009: Historical SAM Variability. Part 1: Century length seasonal reconstructions. J. Climate, 22, 5319-5345.