🌎 A brief Introduction to Atmospheric Circulation 🌍
🌴Introduction to latidunal circulation features with Hadley Cells🌦
Schematic of the Hadley cell ("The Waveform Diary" blog, "The mystery of the shifting tropical rain belt", M. Weirathmueller).
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Our planet is an incredible system with its atmosphere, continents, mountains, and oceans, all of which shape the weather. It is fascinating. So here is a brief introduction to a spectacular meteorological phenomenon that's happening right before your eyes: the Hadley Cells. |
Eumetsat tropical air mass rgb msg 0 degree |
Whether on the surface or at altitude, the circulation of atmospheric
air on a global scale - that of our planet - can be seen as the result
of two combined movements: a
zonal circulation which, depending on
the meridian zone considered, progresses westwards or eastwards roughly
following the direction of the Earth's parallels, and a
meridian circulation which sometimes
heads towards the equatorial regions and sometimes towards the polar
regions roughly following the direction of the Earth's meridians.
However, in both hemispheres, the meridian circulation of air within the
intertropical meridian zone continues continuously through a particular
system of huge convective cells, known as Hadley cells.
These cells lift the equatorial air at high altitude and transport to
the temperate zones the excess of energy previously accumulated in the
form of heat and humidity by this air. Then, once they have fallen back
to low altitude, they return to the tropics, again taking on the same
energy, provided directly and indirectly by solar radiation.
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The Hadley cells are named after the English scientist George Hadley, who in 1735 devised a meridional wind circulation based on thermal ascents at the equator and thermal subsidence at the poles, which explains the formation of trade winds by the Earth's rotation. Their existence, however, was first foreseen by the English astronomer Edmond Halley, author of the first ocean wind map in 1686. (Météo France) |
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