Modulation of the Madden-Julian Oscillation on global flood and fire, and other extreme events

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Tuesday, 4 February 2014: 4:00 PM
Room C114 (The Georgia World Congress Center )
Chidong Zhang, Univ. of Miami/RSMAS, Miami, FL

The Madden-Julian Oscillation (MJO) is known to influence different types of weather and climate extreme events. This presentation first provides a quick survey of such influences documented in the literatures. Then it discussed in details recent results of how and where global flood and wildfire are modulated by the MJO. As its convective center moves eastward from the Indian Ocean into the Pacific, the occurrence frequencies of severe floods and fires fluctuate on intraseasonal timescales in many regions of the world. The fluctuations can be measured by comparing periods with and without prominent MJO events, or between MJO phases that characterize the longitudinal locations of positive and negative anomalies of its precipitation. With statistical significance tests, it is demonstrated that the MJO may either enhance or reduced the occurrence frequency of flood and fires. Possible physical causes of the MJO influences on floods and fires are discussed.