Saturday, March 8, 2014

The Gobi Desert

The Gobi Desert, covering more than 500,000 square miles, is the largest desert in Asia.  This vast and varied ecosystem stretches across southern Mongolia and northwestern China; it is bounded by the Tibetan Plateau to the southwest, the Altai Mountains to the northwest, the Mongolian steppes to the north, the Yin Mountains to the ESE and the Yellow River Valley to the southeast.  Known for its extreme temperature ranges from summer to winter and throughout any given day, this high, northern desert sits on a plateau with elevations of 3000 to 5000 feet; its desert ranges add another 1000 to 2000 feet of elevation.

While images of the Gobi often display towering sand dunes, most of the desert is covered by bleak gravel plains, rocky badlands and sparse grasslands, broken by widely scattered oases harboring shrubs and desert trees.  Native wildlife includes bactrian camels, black-tailed gazelles, a dwindling population of Gobi bears, the Asiatic wild ass and jerboas. Though important trade routes have crossed the Gobi throughout human history and some modern roadways penetrate its core, most of the small cities and towns of this desert region are found along its periphery, leaving the great majority of its expanse to wildlife, miners and nomadic herders.

Lying in the rain shadow of the Himalayas and associated ranges, the Gobi Desert is far from any marine moisture.  To its west is a vast continental land mass with numerous mountain ranges and relatively dry lowlands and little moisture reaches the Gobi from the South China Sea, to its southeast.  Indeed, what little precipitation falls on the Gobi Desert (less than 8 inches per year) arrives primarily as snow, carried on fierce winds from Siberian storm systems.  Throughout the past Century, the desert has been expanding into western China, the consequence of deforestation and overgrazing; while efforts are underway to restore forests and grasslands in that region, global warming may exacerbate the desertification.