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21/12/19/2251234 story

New Meteorological Phenomenon Dubbed "Atmospheric Lakes"

posted by martyb on Monday December 20 2021, @01:08AM   

upstart writes:

New meteorological phenomenon dubbed 'atmospheric lakes':

Brian Mapes, an atmospheric scientist at the University of Miami who recently noticed and described the unique storms, will present his findings on Thursday, 16 December at AGU's Fall Meeting 2021.

Like the better-known streams of humid, rainy air called atmospheric rivers that are famous for delivering large amounts of precipitation, atmospheric lakes start as filaments of water vapor in the Indo-Pacific. These phenomena are defined by the presence of water vapor concentrated enough to produce rain, rather than being formed and defined by a vortex, like most storms on Earth. Unlike the fast-flowing atmospheric rivers, the smaller atmospheric lakes detach from their source as they move at a sedate pace toward the coast.

Atmospheric lakes begin as water vapor streams that flow from the western side of the South Asian monsoon and pinch off to become their own measurable, isolated objects. They then float along ocean and coastal regions at the equatorial line in areas where the average wind speed is around zero.

In an initial survey to catalog such storms, Mapes used five years of satellite data to spot 17 atmospheric lakes lasting longer than six days and within 10 degrees of the equator, in all seasons. Lakes farther off the equator also occur, and sometimes those become tropical cyclones.

The atmospheric lakes last for days at a time and occur several times a year. If all the water vapor from these lakes were liquified, it would form a puddle only a few centimeters (a couple inches) deep and around 1,000 kilometers (about 620 miles) wide. This amount of water can create significant precipitation for the dry lowlands of eastern African countries where millions of people live, according to Mapes.

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Original Submission

• Karma and Dharma(Score: 0) by Anonymous Coward on Monday December 20 2021, @02:56AM

  by Anonymous Coward on Monday December 20 2021, @02:56AM (#1206546)

  We all get what's coming to us.

  Ohm.

• Dead calmDead calm (Score: 2) by MIRV888 on Monday December 20 2021, @06:00AM (1 child)

  by MIRV888 (11376) on Monday December 20 2021, @06:00AM (#1206586)

  Wind speeds of 0 along the equator sounds magical. So brisk, and apparently rainy on occasion.
  I wonder what the evaporative cloud circulation is like in a dead calm atmospheric lake

  • Re:Dead calm(Score: 0) by Anonymous Coward on Monday December 20 2021, @01:15PM

    by Anonymous Coward on Monday December 20 2021, @01:15PM (#1206620)

    The doldrums are scary if you are trying to get somewhere by sail boat.
    https://oceanservice.noaa.gov/facts/doldrums.html [noaa.gov]

    Known to sailors around the world as the doldrums, the Inter-Tropical Convergence Zone, (ITCZ, pronounced and sometimes referred to as the “itch”), is a belt around the Earth extending approximately five degrees north and south of the equator. Here, the prevailing trade winds of the northern hemisphere blow to the southwest and collide with the southern hemisphere’s driving northwest trade winds.

    Due to intense solar heating near the equator, the warm, moist air is forced up into the atmosphere like a hot air balloon. As the air rises, it cools, causing persistent bands of showers and storms around the Earth’s midsection. The rising air mass finally subsides in what is known as the horse latitudes, where the air moves downward toward Earth’s surface.

    Because the air circulates in an upward direction, there is often little surface wind in the ITCZ. That is why sailors well know that the area can becalm sailing ships for weeks. And that’s why they call it the doldrums.

    Parent

• No coriolis(Score: 2) by hendrikboom on Monday December 20 2021, @03:51PM

  by hendrikboom (1125) on Monday December 20 2021, @03:51PM (#1206662) Homepage Journal

  There's very little Coriolis acceleration near the equator. So no cyclones.