University of Miami Rosenstiel School of Marine and Atmospheric Science graduate student Marybeth Arcodia has discovered a link between tropical weather and US rainfall during El Nino years.
Arcodia analyzed data to understand how the Madden-Julian Oscillation (MJO) leads to pressure and rainfall anomalies over the North Pacific and North America, and found that when both El Nino Southern Oscillation (ENSO) and MJO occur simultaneously, the rainfall pattern typically seen from ENSO can change considerably for a few days to week due to MJO interference.
Researchers say this pattern is why, as an example, the 2015 El Nino caused California to have considerably less rainfall than expected, yet the Mississippi River basin was heavily flooded.
Arcodia said, “Although the source of changes in rainfall patterns is coming from thousands of miles away in the tropical Indian and Pacific oceans, our study shows just how connected the tropics and the United States can be.”