The Southern Oscillation Index (SOI) has risen over the past two weeks, recovering from the dip associated with tropical cyclone Evan, and is once again neutral. The latest (13 January) 30-day SOI value is +1.0.
Sustained positive values of the SOI above +8 may indicate a La Niña event, while sustained negative values below −8 may indicate an El Niño event. Values of between about +8 and −8 generally indicate neutral conditions. "
目前看来2013年回归拉妮娜是早晚问题,SOI估计将保持上升势头