Antonio Manaytay – Fourth Estate Contributor
Pasadena, CA, United States (4E) – A recent study had found that more than half of the total water flowing in the east and west coasts of North America, Southeast Asia, and New Zealand have been due to the precipitation from atmospheric rivers. Globally, however, the atmospheric rivers account some 22 percent of the total volume of fresh water flowing on land surface.
In other places of the world where the influence of the atmospheric rivers is strongest the likelihood of floods could be as high as 80 percent. The likelihood of having a drought is as high as 90 percent in areas where it is absent.
The study, published in the journal Geophysical Research Letters, was the first to have estimated the impact of the atmospheric rivers on the global floods and droughts, and the number of people affected by the atmospheric phenomena.
“This new work quantifies the potential impacts of atmospheric rivers on important freshwater quantities, such as snowpack, soil moisture, and the occurrence of droughts and floods across the globe,” study co-author Duane Waliser said.
Waliser, who is the chief scientist of the Earth Science and Technology Directorate at NASA’s Jet Propulsion Laboratory in Pasadena, California, said the recent study could help in improving the “observing and modeling systems that are used for forecasting atmospheric rivers.”
Atmospheric rivers are long, relatively narrow regions in the atmosphere responsible for most of the horizontal transport of water vapor outside of the tropics and into the continents and the polar regions.
Previous studies had accounted the effects of the atmospheric rivers on the hydrology of some regions. These studies, however, were not as extensive as the recent study which considered the impact on the global hydrology.
The atmospheric rivers, according to the study, had impacted at least 300 million people worldwide each year exposing them to the dangers brought about by floods and droughts.
Research on atmospheric rivers in the past had been focused on how they had helped shape the climate and water cycle of the polar regions; and their impacts to North America and western Europe.
To determine the amount of water the water vapor-carrying jets had contributed to streamflow, snowpack, and soil moisture the recent study used the previous data and information of atmospheric rivers. The scientists involved in the study also identified the regions and the number of people affected by the atmospheric phenomenon.
“By incorporating demographic data into our study, we have found that globally, a large number of people are exposed to hazards that stem from atmospheric rivers,” study lead author Homero Paltan explained, adding that “they have a considerable impact that we’re only beginning to understand and measure.”
Paltan said the impacts of atmospheric rivers could vary in different places. It could either cause flooding or drought in other areas but it could also cause both flooding and drought in some places.
Places like the Iberian Peninsula, northern Iran, the Yellow River Valley in China, and Australia and New Zealand may experience droughts similar to the one that hit California recently. These places, Paltan said, could also suffer from extreme flooding due to atmospheric rivers.
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