Science.-A Hazard Scale 1 to 5 for Atmospheric Rivers – Publimetro México

Madrid, 17 (Europe Press)

Vast airways of water vapor flowing from Earth’s tropics to higher latitudes can bring much-needed rain to parched lands. But in an extreme form, they can also cause destruction and loss of life, as recently occurred in parts of California. Its effects, both dangerous and beneficial, are felt all over the world.

Research on atmospheric rivers has largely focused on the western coasts of North America and Europe. The new findings help expand our understanding of how these storms originate, develop, and impact communities around the world. Also, the ratings can help meteorologists better warn people so they can plan.

The results also revealed an increasing number of atmospheric river events worldwide and across all scales, with maximum activity in mid-latitude oceans (temperate belts roughly between 30 and 60 degrees north and south).

To help predict the likely strength and impacts of storms as they make landfall on North America’s west coast, meteorologists from the Scripps Institution of Oceanography at the University of California, San Diego, along with the National Weather Service, presented an atmospheric river in 2019.

Ranking them from 1 to 5, or weakest to strongest, the scientists sought to distinguish between primarily beneficial storms and primarily dangerous storms. By one estimate, insured losses due to flood damage increase 10 times with each range hike, with AR 5 events associated with an average damage amount of $260 million in the western US.

Although the term “atmospheric river” was coined in 1994, the effects of storms were felt long before that. Scientists have estimated that about 300 million people worldwide are at risk of flooding from atmospheric rivers that carry, on average, more than twice as much water vapor as the flow of the Amazon River. A growing body of research is exploring how these storms play a critical role in shaping the global water cycle from the Andes to the Arctic, where moisture from atmospheric rivers was recently found to be melting and slowing the seasonal recovery of sea ice.

In the new study, scientists created a database of atmospheric river events on a global scale from 1980 to 2020, using a computer algorithm to automatically select tens of thousands of events in Modern-Era Retrospective Analysis for research and applications. Release 2 (MERRA-2), a new NASA analysis of historical atmospheric observations. To classify the events, the study authors applied the atmospheric river scale, which is based on the expected duration of the storm and the maximum rate of water vapor transport.

Over the 40 years studied, high-range storms lasted longer and traveled farther than low-range storms. Average travel distance was found to be about 650 km for AR 1 and about 4,700 km for AR 5, while average duration was about 17 hours for AR 1 and 110 hours for AR 5. Storms of larger range (AR 4 and AR 5) They are less common and tend to start their life cycles near the tropics and end in cooler latitudes.

In addition, scientists have detected an increase in the frequency of atmospheric rivers during strong El Niño years.