The Madden-Julian Oscillation: Subseasonal Prediction in Present and Warmer Climates
Prof. Eric Maloney
Colorado State University
Monday October 16, 2023, 2 PM ET
The Madden-Julian oscillation (MJO) is the leading mode of subseasonal variability in the tropical atmosphere. It is important for subseasonal prediction because it modulates weather extremes in both the tropics and extratropics. After a brief survey of some of these impacts, the implications of the MJO for prediction in current climate will be examined with different complexity models ranging from the NOAA Unified Forecasting System to a neural network. It is shown that MJO errors in the tropics in UFS lead to substantial North American precipitation forecast errors, and that these can be ameliorated by correcting the evolution of the MJO in the tropics.
Climate warming produces various basic state changes that produce complex effects on MJO amplitude, propagation characteristics, and teleconnections. While MJO precipitation variability goes up in a warmer climate with a moister lower troposphere, increases in tropical static stability reduce the strength of MJO circulations per unit precipitation. Coupled with other shifts such as changes in mid latitude jets, how extratropical MJO teleconnections will change in a warmer world are highly uncertain. Further, the effects of MJO changes on tropical extremes such as tropical cyclones are confounded by possible spatial shifts in MJO activity, and the competing impacts from distinct MJO wind and precipitation changes. Evidence that some changes to the MJO are already detectable in the observed record will be presented, particularly in the ratio of MJO wind to precipitation amplitudes. The presentation will also discuss uncertainties in MJO change related to the pattern of tropical SST change, whether it is more El Niño or La Niña-like. The implications of these uncertainties for subseasonal and seasonal prediction in a warmer climate will be discussed.
Prof. Eric Maloney earned a Ph.D in the Department of Atmospheric Sciences at the University of Washington in 2000. He then studied under a NOAA Climate and Global Change postdoctoral fellowship at the National Center for Atmospheric Research before joining the faculty of the College of Oceanic and Atmospheric Sciences at Oregon State University in 2002 as an Assistant Professor. Prof. Maloney joined the faculty of the Department of Atmospheric Science at Colorado State University in 2008, where he is now a Professor and Department Head.
He has contributed over 150 publications in the peer reviewed literature during his career. These publications have covered various topics of tropical meteorology including observations, modeling, and theoretical studies of tropical intraseasonal variability and easterly waves, including a large body of literature on the Madden-Julian oscillation (MJO). Prof. Maloney also has other research contributions on the tropical diurnal cycle, midlatitude air-sea interactions, regional climate change, tropical-extratropical interactions, changes in tropical convective extremes in a warmer climate, and El Niño-Southern Oscillation, among other topics.
Prof. Maloney has served as editor of Journal of Climate, and Associate Editor of Monthly Weather Review. He has served as co-chair of the NOAA MAPP Model Diagnostics Task Force, member of the NOAA MAPP S2S Task Force, and as former chair of the WGNE MJO Task Force. He was awarded the AGU Ascent Award in 2016, and was named an AMS Fellow in 2023. Prof. Maloney has also been involved in various other national and international programs, and has participated in and helped plan several international field programs over the last two decades, including the OTREC field campaign that was based in Costa Rica in fall of 2019.
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