On the Collapse of the Surface Easterly Wind in the Eastern Equatorial Pacific in the 2015 El Nino

Wind speed and direction measurements were recorded at 10-m height by the NASA SeaWinds scatterometer instrument on the NASA QuikSCAT satellite (June 1999 – November 2009), the ESA Advanced Scatterometer (ASCAT-A) instrument on the first EUMETSAT Meteorological Operational (MetOp-A) satellite (May 2007 – present), and the NASA RapidScat instrument on the International Space Station (September 2014 – present). The composite longitudinal distributions of monthly-averaged surface vector winds along the equator were determined during the four El Nino and four La Nina events that had occurred since the 1997-1998 El Nino super-event. West of 150°W the average strength of the surface westward wind speed in El Nino was more than 2 m s^-1 smaller compared to that in four La Nina events. No such reduction in westward wind speed occurred east of 150°W. We will discuss the response of surface westward winds along the equator in the 2015 El Nino event, which has been predicted to become a super-event. Additionally, we will describe the response of MISR eastward winds in the upper troposphere in the 2015 El Nino event.