Search results
Results from the WOW.Com Content Network
Sailing stones (also called sliding rocks, walking rocks, rolling stones, and moving rocks) are part of the geological phenomenon in which rocks move and inscribe long tracks along a smooth valley floor without animal intervention. The movement of the rocks occurs when large, thin sheets of ice floating on an ephemeral winter pond move and ...
The wind pattern that results from the continent/ocean insolation temperature gradient is known as a monsoon. Values of summer insolation are more important for a region's climate than winter values. This is because the winter phase of a monsoon is always dry.
The average annual precipitation in low latitude deserts is less than 250 mm. Relative humidity is very low – only 10% to 30% in interior locations, and even the dewpoints are typically very low, often being well below the freezing mark. Some deserts do not have rainfall all year round, they are located far from the ocean.
The width of the Tethys Ocean is believed to have been roughly the same as that of the Indian Ocean. [3] It is well documented that the Indian Ocean can provide onshore-moving air masses with enough moisture to support a monsoon-driven environment. Thus, the Tethys should have been able to as well.
The modern, arid Sahara. The Sahara was not a desert during the African humid period. Instead, most of northern Africa was covered by grass, trees, and lakes. The African humid period (AHP; also known by other names) was a climate period in Africa during the late Pleistocene and Holocene geologic epochs, when northern Africa was wetter than today.
Most calendar-based partitions use a four-season model to demarcate the warmest and coldest seasons, which are further separated by two intermediate seasons. Calendar-based reckoning defines the seasons in relative rather than absolute terms, so the coldest quarter-year is considered winter even if floral activity is regularly observed during ...
The Sonoran Desert is clearly distinct from nearby deserts (e.g., the Great Basin, Mojave, and Chihuahuan deserts) because it provides subtropical warmth in winter and two seasons of rainfall (in contrast, for example, to the Mojave's dry summers and cold winters). This creates an extreme contrast between aridity and moisture.
Many people think of deserts as consisting of extensive areas of billowing sand dunes because that is the way they are often depicted on TV and in films, [54] but deserts do not always look like this. [55] Across the world, around 20% of desert is sand, varying from only 2% in North America to 30% in Australia and over 45% in Central Asia. [20]