Tonight we present the first GEOS talk of the semester! It’s a great one: Christina Karamperidou of Columbia University will be speaking about research she’s doing on the El Nino – Southern Oscillation (ENSO). This is an ocean-atmosphere interaction that appears in nearly every Oceanography and Meteorology textbook. The oscillation is between the ‘normal’ state, where there is upwelling in the Pacific along the coast of Peru, and an associated pool of warm surface water in the western Pacific. Winds and rain systems help sustain this configuration, wherein the upwelling brings cold, nutrient rich water to the surface. These nutrients feed a bonanza of ocean life, including economically important fishstocks. The El Nino state involves the shutdown of upwelling and a change in the configuration of the winds and atmospheric pressure systems. The fish-stocks collapse because of the loss of nutrients. 

This system is important because it has effects all across the globe. In some places it can encourage droughts, in others, devastating rains. Variation in the system is also associated with the number, strength, and even the tracks of the Atlantic Hurricanes, which sometimes hit us here in NY!

There’s also a third phase to the oscillation, called La Nina. This is basically an intensified version of the normal system, with really strong upwelling and a wider swath of cold surface waters. The ENSO has been in a La Nina phase for a while now, and that is what is responsible for this mild, nearly snow-less winter we’ve been having in NY.

So events in another ocean, in another hemisphere, have teleconnections that reach right across the world and hit us!

Christina Karamperidou will specifically be talking about how we predict what the next ENSO phase will be (it doesn’t just cycle through them in sequence) and how variability within the system contributes to our uncertainties in those predictions.

We’re all looking forward to it, this will be a great talk to kick off the new semester with!