The development of distinct sea surface temperature pattern in the North Pacific Ocean can help meteorologists predict increased occurrences of heat waves by up to 50 days ahead, at least in the United States' eastern half. The pattern shows the collision between cooler-than-average and warmer-than-average waters.
Depending on how distinct the building pattern is - with the warmer waters hitting the cooler waters - the chances of extreme heat waves in a particular day or week can increase by three-fold. The research was conducted by the National Center for Atmospheric Research (NCAR).
Heat waves during the summer are one of the most lethal weather events that can impact not just people, but also farming activities and energy use. According to lead author and NCAR postdoctoral researcher Karen McKinnon, giving farmers and city planners an advanced warning about an upcoming heat wave can help avoid worst-case scenario consequences.
In the study, the researchers divided the United States into regions that most likely experience severe heat waves at the same time. Out of the resulting heat waves regions, they focused on the area that stretches across most of the Midwest all the way up to the East Coast. This focused region comprised of both heavily populated cities and agricultural areas.
The team investigated if there is a connection between the severe heat waves in the country's eastern half and the irregularities in the worldwide sea surface temperature. They discovered a pattern in the middle of the North Pacific Ocean and named it the Pacific Extreme Pattern. They learned that the pattern is present not only during instances of heat waves but way ahead of the weather event.
"Whatever mechanisms ultimately lead to the heat wave also leaves a fingerprint of sea surface temperature anomalies behind," said McKinnon.
The team wanted to see how well the Pacific Extreme Pattern can predict upcoming heat waves retrospectively. They analyzed gathered data from 1,613 weather stations in eastern U.S. from 1982 to 2015 and compared it with the same-period data of the sea surface temperatures.
Fifty days prior to a heat wave event, they were able to detect an increase in the chances - from one in six to one in four - that a heat wave will strike in a specific week. Thirty days prior or closer, the pattern was able to hindcast the odds - about one in two - that a heat wave will strike on a specific day.
The new technique can help improve current seasonal forecasts. The ability to make long-range predictions for singular heat wave events can help society prepare better than relying on current forecasts alone.
The National Science Foundation funded the research, which was published in the Nature Geoscience journal on March 28. The study team also included researchers from various universities, including the University of Washington, Pennsylvania State University and Harvard University.
Photo: AIRS, The Atmospheric Infrared Sounder | Flickr
