Erosion by Wind: Desert Landscapes

Last lesson for exam three focuses on erosion, specifically by wind.
Rivers are primary for transport, groundwater for storage, but rivers drive erosion.
Wind becomes the main driver of erosion and transportation where water is scarce.
Desert landscapes on Mars are studied using Earth as a reference due to observable factors here.
Drones capture aerial images of Earth deserts, matched with Mars to determine if features are aeolian (wind-driven) or fluvial (water-driven).
By the lecture's end, we should understand agents of erosion, transport, and deposition.
We will review the transportation topic covered in a previous lecture.
Focus will be on desert environments and associated terminology.

Wind is air movement in the atmosphere driven by convection due to pressure differences.
Warm, moist air leads to low-pressure systems.
Warmer air has a higher capacity to hold water, increasing humidity.
Heated air rises, then cools and condenses at higher altitudes, causing precipitation.
Cool, dry air descends and cycles back, picking up residual moisture and contributing to desert formation at around 30-degree latitudes north and south of the equator.
Key factors are temperature and humidity.
$H<em>2O$ molecules (mass ~18) rise easier than $O</em>2$ or $N_2$ (mass ~30).
Wind speed depends on the pressure gradient; a greater pressure difference means higher wind speed.
Las Vegas typically has low wind due to minimal temperature variation.
Significant elevation changes or hurricanes cause strong winds due to temperature differences.
Wind direction is named after the direction from which it blows (e.g., westerly winds blow from the west).

If only temperature influenced wind, hot air would rise at the equator and cool in northern regions.
However, this model is too simple; humidity and the Coriolis effect also play major roles.
The Coriolis effect, caused by Earth's rotation, deflects wind and water direction.
In the Northern Hemisphere, deflection is to the right (westward); in the Southern Hemisphere, it's to the left.
This effect contributes to desert formation around 30 degrees north and south.