Current Status and Forecast. n Tropical Pacific sea-surface temperatures (SSTs) have warmed from La NiÃ±a. Modoki (below-average SSTs, centered in the central tropical Pacific) to ENSO-neutral. Current SSTs range from slightly below average in the central Pacific to slightly above. average in the eastern Pacific. n The Climate Prediction Center (CPC) defines a La NiÃ±a event as having ONI values. of -0.5Â°C or colder for 5 consecutive months.
Convection currents move tectonic plates when there is heat inside the mantle that is rising and falling. The radioactive decay in the core is responsible for the convection currents.
It is believed that between the rising convection currents (i.e. the mid-oceanic ridges) and the sinkÂ­ing currents (i.e. the subduction zone) the horizontal motion of the convection current exerts a dragging force on the lithosÂ­pheric plates and causes the plate motion.