SOURCE: NASA

DATE: September 12, 2018

SNIP: Most of us are familiar with heat waves on land, but in a warming world, heat waves are starting to become common in the ocean, too. One basin in particular, the normally cool Gulf of Maine in the Northwest Atlantic Ocean, has seen several heat waves in recent years and has spent most of 2018 with unusually warm water temperatures.

On August 8, 2018, scientists using satellite data and sea-based sensors measured the second warmest sea surface temperatures ever observed in the Gulf of Maine. Average water temperatures reached 20.52 degrees Celsius (68.93 degrees Fahrenheit) that day, just 0.03°C (0.05°F) below the record set in 2012.

The map on this page shows sea surface temperature anomalies as compiled by NOAA’s Coral Reef Watch, which blends observations from the Suomi NPP, MTSAT, Meteosat, and GOES satellites and from computer models. Shades of red and blue indicate how much water temperatures were above or below the long-term average for the region. The map [on this post] shows conditions on August 8, the near-record setting day.

The heatwave of 2018 fits with a much longer trend in the region, which is among the fastest-warming parts of the global ocean. In the past three decades, the Gulf of Maine has warmed by 0.06°C (0.11°F) per year, three times faster than the global average. Over the past 15 years, the basin has warmed at seven times the global average. The Gulf has warmed faster than 99 percent of the global ocean.

“Climate change is likely contributing to the circulation changes through melting in Greenland and Arctic, as well as making long-stretches of warm weather more likely,” said Andrew Pershing, chief scientist of the Gulf of Maine Research Institute (GMRI).