What is the average desert rainfall

Widely considered the driest place in the world, it has an average rainfall of as little as 0. Even that much water has been hard to come by, with climate records suggesting no significant rain has fallen in the past years.

That has implications not just on Earth, but on arid planets like Mars. Though the Atacama is indeed an all-but-sterile place, there are some organisms that manage to scratch out an existence there. At least sixteen microbial species are known to populate the deep soils of long-dry lake beds, using nitrates—a salt form of nitric acid—as food.

After the Atacama was bathed by actual, honest-to-goodness water, however, things got rough. Desert biomes are the driest of all the biomes. In fact, the most important characteristic of a desert is that it receives very little rainfall.

Most deserts receive less than mm a year compared to rainforests, which receive over 2, mm. That means that the desert only gets 10 percent of the rain that a rainforest gets! See the Communities of the Sonoran Desert Region"for more information. As this equatorial air descends upon the Sonoran Desert region, it creates a very stable and warm atmosphere. The rains stay away until the high pressure system weakens, allowing moisture to slip into the region.

The excitement of a summer rain reminds us that water is precious in this arid environment. Long periods of drought are the norm, and desert plants and animals are adapted to water scarcity.

But what about the millions of people now living in the burgeoning cities of the Sonoran Desert region? From to alone, Phoenix grew by 22 percent and its metropolitan population topped 2,, With per capita water use exceeding gallons per day in Phoenix, the aridity of the desert seems to impose little restraint on these modern desert dwellers.

New golf courses appear to spring up every week in our desert cities Phoenix and Tucson alone had more than public and private golf courses in How can the desert supply all this water? The answer is that it can't. Rainfall replenishes only a fraction of the fossil groundwater withdrawn every year from ancient aquifers laid down thousands of years ago. The aquifer underlying central Tucson has fallen by more than feet in the last 50 years.

To supplement depleting groundwater supplies, distant river basins are diverted through massive water projects to transport water into this arid region. By mining fossil groundwater and importing river water from more humid climates, the residens of the Sonoran Desert have buffered themselves from the reality of their arid environment. This dependence on imported and non-renewable sources of water must be addressed in planning for the long-term sustainability of our desert cities.

The word monsoon refers to a system of winds that changes seasonally, bringing wet and dry periods to a region. In the Sonoran Desert, the summer monsoon consists of winds from the sea flowing inland to fill the partial vacuum created by rising continental air warmed by the summer sun.

These winds bring moisture. These westward-moving winds actually circle around into the area and often reach the Sonoran Desert as southeasterly winds. This is one reason people in the past assumed that monsoon moisture comes from the Gulf of Mexico. Recent studies, however, lead many meteorologists to believe that most moisture from the southeast is drained by the foot m Mexican Sierra Madre and so doesn't reach the Sonoran Desert.

This issue is yet unresolved. Once Pacific moisture reaches our area, usually in July, the increased humidity means we really begin to feel the heat. During nighttime in the summer, the temperature can drop to almost freezing. Archaeologists have discovered that about every 20, years the Sahara alternates from a dry, uninhabitable desert to a lush, green oasis.

Currently, there are two climatic areas in the Sahara desert. One is a dry subtropical climate in the north, and the other is a dry tropical climate in the south. The subtropical climate in the north has very high annual temperatures and colder winters. The northern region of the desert has two precipitation periods.

Most precipitation falls from December through March. August is also a common time for precipitation due to thunderstorms that can even cause flash floods.

The tropical climate in the south has more mild, dry winters, and a hot, dry season before the rains arrive. Much of the rainfall precipitation occurs as thunderstorms, and this region receives five inches per year on average.

In the western area of the desert, the cool winds of the Canary Current reduce air temperatures, which also reduces rainfall. This area more commonly experiences humidity and occasional fog. The Sahara is arguably the most famous desert in the world.