Weather (WX)

[Ref ISBN978-1-56027-901-3, #Pilot’s Handbook of Aeronautical Knowledge, FAA-H-8083-25B Page 12-7 to 12-12]

Primary cause of all WX?

Uneven heating on the earths’ surface is the main cause of all WX!

Causes of temperature variations?

  1. Diurnal variation (daytime heating and nighttime cooling)
  2. Seasonal variation
  3. Latitude
  4. Topographical issue
  5. Altitude



Why temperature at the Equator is warmer (hotter) than High latitude areas (poles)?

Due to the curvature of the Earth, for given amount of radiation energy from the sun has different effect on the Earth’s surface. At higher latitudes, the energy is spray over a larger surface area and that is much more concentrated near the equator.

Also, the atmosphere is essentially covered by gas masses. The radiation energy from the sun has to travel longer distance to the poles in comparison to the equator.


In short, the global atmospheric circulation is caused by the Earth’s rotation as well as uneven heating. This causes different part of the world heating up differently and there is constant movement of air around the surface of the Earth.

In a more detailed explanation, the sun is the main source of energy, which transfer to the Earth in the form of radiation. Then, the energy is absorbed by the clouds, atmospheric gases and the Earth’s surface. Also, the human activities also give contribution to uneven heating of the earth. The atmosphere is almost constantly in motion as it strives to reach equilibrium.


Two (2) kinds of atmospheric motion

  1. Convective currents (upward and downward motion) – small areas of local circulation
  2. Wind (horizontal motion)large scale atmospheric circulation



Convective Currents

convective currents occur when uneven heating of the air creates small areas of local circulation
(Updrafts over pavement and downdrafts over water or expansive areas of vegetation like a group of trees)

Convective currents cause the bumpy, turbulent air as well as the local wind circulation pattern – i.e sea breeze and land breeze


Read More –

#Why do we get prevailing winds?

#What’s Jet Stream?

#Three cells

Weather Radar – RDR-4000 IntuVue™

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