Atmospheric lakes are long-lived swimming pools of water vapor that happen over the western Indian Ocean and convey water to dry lowlands alongside East Africa’s shoreline.
Long-lived lakes of water vapor within the environment are noticed to happen over the western Indian Ocean. Their dynamics resemble these of a well-studied theoretical and simulation paradigm for tropical disturbances referred to as self-aggregation. Image credit score: Mapes & Tsai.
Like the better-known streams of humid, wet air referred to as atmospheric rivers which are well-known for delivering giant quantities of precipitation, atmospheric lakes begin as filaments of water vapor within the Indo-Pacific.
These phenomena are outlined by the presence of water vapor concentrated sufficient to supply rain, reasonably than being shaped and outlined by a vortex, like most storms on Earth.
Unlike the fast-flowing atmospheric rivers, the smaller atmospheric lakes detach from their supply as they transfer at a sedate tempo towards the coast.
Atmospheric lakes start as water vapor streams that circulation from the western facet of the South Asian monsoon and pinch off to turn out to be their very own measurable, remoted objects.
They then float alongside ocean and coastal areas on the equatorial line in areas the place the typical wind velocity is round zero.
In an preliminary survey to catalog such storms, University of Miami atmospheric scientists Brian Mapes and Wei-Ming Tsai used 5 years of satellite tv for pc knowledge to identify 17 atmospheric lakes lasting longer than six days and inside 10 levels of the equator, in all seasons.
Lakes farther off the equator additionally happen, and typically these turn out to be tropical cyclones.
The atmospheric lakes final for days at a time and happen a number of occasions a yr.
If all of the water vapor from these lakes have been liquified, it might kind a puddle only some centimeters (a pair inches) deep and round 1,000 km (620 miles) large.
“This amount of water can create significant precipitation for the dry lowlands of eastern African countries where millions of people live,” Dr. Mapes mentioned.
“It’s a place that’s dry on average, so when these atmospheric lakes happen, they’re surely very consequential.”
“I look forward to learning more local knowledge about them, in this area with a venerable and fascinating nautical history where observant sailors coined the word monsoon for wind patterns, and surely noticed these occasional rainstorms, too.”
“Weather patterns in this region of the world have received little attention from meteorologists, limited mostly to studies of rain and water vapor on a monthly rather than day-to-day scale,” he added.
“I’m working to understand why atmospheric lakes pinch off from the river-like pattern from which they form, and how and why they move westward.”
“This might be due to some feature of the larger wind pattern, or perhaps that the atmospheric lakes are self-propelled by winds generated during rain production.”
The researchers offered their outcomes this month on the American Geophysical Union Fall Meeting 2021 (AGU21).
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Brian E. Mapes & Wei-Ming Tsai. Long-lived vapor lakes over the Indian Ocean: closest outside phenomenon to the self-aggregation paradigm? AGU21, summary # A42B-04