Observations of eastward propagation of atmospheric intraseasonal oscillations from the Pacific to the Atlantic

Satellite-derived QuikSCAT winds and NOAA Outgoing Longwave Radiation (OLR) measurements for the period of 2000–2006, together with reanalysis of winds from a longer record, are analyzed to understand the sources of this 40–60-day wind variability and the global propagation of the Madden-Julian Oscillation (MJO) surface signatures.

The results demonstrate that the MJO propagated eastward from the Indo-Pacific Ocean to the Atlantic during winter and spring of 2002, causing 40–60 day wind variations in the equatorial Atlantic. The Isthmus of Panama appears to be a dominant pathway for these surface wind anomalies to propagate into the Atlantic, where they can produce important climate impacts. This result is consistent with previous work that has demonstrated a strong MJO influence on the North American Monsoon (NAM) region, and complements other work demonstrating the propagation of intraseasonal wind anomalies and accompanying sea level pressure signals associated with dry equatorial Kelvin waves that reach the Caribbean through the Panama gap.