<P> Deserts are also classified, according to their geographical location and dominant weather pattern, as trade wind, mid-latitude, rain shadow, coastal, monsoon, or polar deserts . Trade wind deserts occur either side of the horse latitudes at 30 ° to 35 ° North and South . These belts are associated with the subtropical anticyclone and the large - scale descent of dry air moving from high - altitudes toward the poles . The Sahara Desert is of this type . Mid-latitude deserts occur between 30 ° and 50 ° North and South . They are mostly in areas remote from the sea where most of the moisture has already precipitated from the prevailing winds . They include the Tengger and Sonoran Deserts . Monsoon deserts are similar . They occur in regions where large temperature differences occur between sea and land . Moist warm air rises over the land, deposits its water content and circulates back to sea . Further inland, areas receive very little precipitation . The Thar Desert near the India / Pakistan border is of this type . </P> <P> In some parts of the world, deserts are created by a rain shadow effect . Orographic lift occurs as air masses rise to pass over high ground . In the process they cool and lose much of their moisture by precipitation on the windward slope of the mountain range . When they descend on the leeward side, they warm and their capacity to hold moisture increases so an area with relatively little precipitation occurs . The Taklamakan Desert is an example, lying in the rain shadow of the Himalayas and receiving less than 38 mm (1.5 in) precipitation annually . Other areas are arid by virtue of being a very long way from the nearest available sources of moisture . </P> <P> Montane deserts are arid places with a very high altitude; the most prominent example is found north of the Himalayas, in the Kunlun Mountains and the Tibetan Plateau . Many locations within this category have elevations exceeding 3,000 m (9,800 ft) and the thermal regime can be hemiboreal . These places owe their profound aridity (the average annual precipitation is often less than 40 mm or 1.5 in) to being very far from the nearest available sources of moisture and are often in the lee of mountain ranges . Montane deserts are normally cold, or may be scorchingly hot by day and very cold by night as is true of the northeastern slopes of Mount Kilimanjaro . </P> <P> Polar deserts such as McMurdo Dry Valleys remain ice - free because of the dry katabatic winds that flow downhill from the surrounding mountains . Former desert areas presently in non-arid environments, such as the Sandhills in Nebraska, are known as paleodeserts . In the Köppen climate classification system, deserts are classed as BWh (hot desert) or BWk (temperate desert). In the Thornthwaite climate classification system, deserts would be classified as arid megathermal climates . </P>

What are the major land features of the desert