[EDITOR’S NOTE: This is Hao Shen’s first contribution to #sciencefriday. Hao is a junior computer science/math double major at MIT whose interests range from image processing techniques to understanding weather forecast models. Welcome to the team, Hao!]
We’ve truly had a wacky winter so far. There have been record highs in Boston whilst Texas experiences blizzard conditions! Is the apocalypse imminent? What has caused this stark disparity? El Niño has played a strong role in controlling the weather of our wacky winter wonderland.
What is El Niño? The NOAA defines it as an increase in sea surface temperature of at least 0.5C in the Pacific equatorial region, averaged over 3 months. The cause for El Niño is still under research but there have been well documented correlations for global weather. What is known is that the band of equatorial waters warms in the East, pushing atmospheric convection in that direction. This decreases upwelling along the Eastern Pacific Coast while also causing increased rainfall. Other correlations include a general increase in temperatures in the northeast and a general decrease in temperatures in the south, which we see in the current winter.
I would like to end this post by briefly touching on global warming. It is easy to attribute the unusually warm weather to global warming, but the incremental increases in temperature due to global warming could not have such a direct impact. In general global weather and circulation is an extremely complex and diverse system subject to both small and large scale changes! Stay tuned for more discussion on the myths and truths of global warming.
If there is interest in the other numerous effects, current status, predictions, etc http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ensostuff/prelude_to_ensofaq.shtml is a great source. I apologize beforehand for the lack in NOAA’s text formatting skills.
Additional sources: http://www.weather.com/news/climate/news/el-nino-outlook-strong-possible-may2015