For the first time, atmospheric rivers have been studied in a global scale by NASA and several partners. Their findings give us a profound understanding of their global impact on floods, droughts and the areas affected by these phenomena.
What Are Atmospheric Rivers?
“Atmospheric rivers are relatively long, narrow, short-lived jets of air that transport water vapor across significant portions of Earth’s mid-latitude oceans, onto the continents and into Earth’s polar regions.” As the water vapor travels across the Pacific and hits land, it gets forced up into the atmosphere and cools, producing significant rainfall.
In this model simulation, white colors are clouds, light blues water vapor, and green to red colors are precipitation areas.
Previous studies were limited to specific regions but, through NASA’s study scientist were able to study these jets of air from a global perspective.
How Do They Influence Earth’s Atmosphere?
These atmospheric phenomena affect greatly many areas of the world. Atmospheric rivers are responsible for flooding events around the world. The study found that in areas like the west and east coasts of North America; Southeast Asia; and New Zealand, atmospheric rivers contribute to precipitation of more than 50 percent of the total water that flows across Earth’s land surfaces. “atmospheric rivers make floods and droughts far more likely — increasing the occurrence of floods by 80 percent..” in areas where atmospheric rivers are more common.
In contrast, the absence of atmospheric rivers can “increase the occurrence of droughts by up to 90 percent”
Dr. Marty Ralph from the Scripps Institution of Oceanography at UC San Diego says, “When they hit California or the West coast, they often last about a day. We might get six to ten in an average year; if we fewer than that we might end up in drought; if we get more than that we end up with flood risk.”
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