Great Desert in Australia . Great desert in North africa . what makes a place ; great desert ??

Question

these 2 great deserts are in different places , completely .

folks , who can help us to understand ?

Answer 1

these are the great low latitudes deserts and have similar climate

Answer 2

they r called grt deserts coz they covers huge area and with grt temp... my country has also grt desert that is dhar desert in rajasthan... greatest thing abt dhar desert is that it has very high temp which makes all deserts great...

Answer 3

Lack of rain.

This lack is primarily caused by a combination of factors - Ocean currents, Mountain ranges & their alignment.

Due to upwelling of a cold current (like 'Canaries current') and part of cold polar current (flowing from W to E) swinging past the western margin of a continent (West Australian current) make desert climate possible. Cold current attracts winds from land thus contributing no moisture laden Ocean currents to the adjacent land.  

Desert are located on Western side of big continents in the mid-latitudes (24 to 36 degrees). Australia, being a small continent with less latitudinal stretch, entirely in the mid-latitudes and no lofty mountains - has the least rainfall (except Antarctica that is a different case altogether) for a continent and has majority of area under desert.

The Eurasia-Africa landmass has Mediterranean Sea in between that is weak (unlike the Oceans) to have effect on the interior continental climates of Eurasia. The desert band here starts with West Africa, the western margin of the landmass in mid-latitudes as 'Sahara', extending to 'Arabian', 'Iranian', 'Indian' (Thar) & 'Central Asian'(Taklamakan, Gobi) deserts.