Last year's record-breaking heatwave, recent droughts and the 2020 Labor Day megafires that swept across Oregon and Washington all share a contributing factor: atmospheric ridges, or elongated regions of high pressure relative to their surroundings that are typically associated with warm and dry conditions at the surface.
More still needs to be known about the key drivers of ridges and how they will be affected by a warming climate. That's why researchers from Portland State University (PSU) and Washington State University Vancouver (WSUV) are teaming up to study atmospheric ridging in current and future climates, thanks to a grant from the National Science Foundation.
Paul Loikith, associate professor of geography and director of PSU's Climate Science Lab, and Deepti Singh, an assistant professor at WSUV and director of WSUV's Climate Extremes and Societal Impacts Lab, said that while ridges are a normal part of the mid-latitude atmospheric circulation, their occurrence and impacts over western North America is influenced by multiple unique factors including proximity to the Pacific Ocean, interactions between the Pacific Ocean and the atmosphere and the complex topography of western North America.
The project aims to advance the basic understanding of the components of the Earth system that influence atmospheric ridges over western North America and investigate how and why ridges will respond to continued global warming. The project will seek to answer three key questions using a combination of observations and climate model simulations:
- How do various atmosphere, ocean and land-surface conditions influence characteristics of atmospheric ridges such as their extent, frequency, persistence and amplitude?
- How are projected changes in ridge characteristics influenced by changes in these physical drivers?
- How do potential future changes in ridge characteristics interact with warming to influence surface climate and extremes of temperature and precipitation in the region?
The findings will help in climate planning and adaptation measures. In a recent study published in the Journal of Climate, Loikith and Singh found that ridges that produce heat waves won't necessarily become more common over the Pacific Northwest in the future, but when ridges do occur, the weather associated with them will be warmer in the future than in the past.
As part of this grant, the team will also work with the Oregon Museum of Science and Industry to develop education and outreach activities and materials to demonstrate these atmospheric features and their impacts to K-12 and community groups in the Portland-Vancouver area.