Daily Quiz: UPSC Prelims Marathon-January 5, 2018

Statement 1 is correct:

The Mediterranean lands receive most of their precipitation in winter when the Westerlies shift equator wards. In the northern hemisphere, the prevailing on-shore Westerlies bring much cyclonic rain from the Atlantic (Typical to Mediterranean Climate). The rain comes in heavy showers and only on a few days with bright sunny periods between them. This is another characteristic feature of the Mediterranean winter rain. Though the downpours are infrequent they are often very torrential and in mountainous districts, destructive floods occur.

Statement 2 is Incorrect:

The Savanna or Sudan Climate is a transitional type of climate found between the equatorial forests and the trade wind hot deserts.

Statement 3 is Correct:

The Mediterranean lands are also known as the world’s orchard lands.

A wide range of citrus fruits such as oranges, lemons, limes, citrons and grapefruit are grown.

The fruit trees have long roots to draw water from considerable depths during the long summer drought.

Source: Physical and Human Geography, Chapter 19, G.C Leong.

The prominence of local winds around the Medi-terranean Sea:

Many local winds, sonic hot, others cold arc common around the Mediterranean Sea. The causes are many and varied. The topography of the region with the high Alps in the north, the Sahara desert in the south, continental interiors in the east and the open Atlantic on the west gives rise to great differences in temperature, pressure and precipitation. Thus, plays an important role in determining the Mediterranean type of climate. Some of the major winds which blows around the Mediterranean Sea are:

1. Mistral: Mistral is a cold wind from the north, rushing down the Rhone valley in violent gusts between 40 and 80 miles per hour. The velocity of the Mistral is intensified by the funneling effect in the valley between the Alps and the Central Massif [Plateau in France].
2. Sirocco: This is a hot, dry dusty wind which originates in the Sahara Desert. The Sirocco blows outwards in a southerly direction (south to north) from the desert interiors into the cooler Mediterranean Sea. After crossing the Mediterranean Sea, the Sirocco is slightly cooled by the absorption of the water vapour. Its scorching heat withers [To dry up or shrivel from loss of moisture] vegetation and crops. This may be ‘blood rain’ because the wind is carrying the red dust of the Sahara Desert.
3. Bora: Occurs along the eastern shore of the Northern Adriatic and is similar in some respects to the Mistral. It is a NE wind occurring chiefly in winter, when it may attain gale force. Violent gusts and squalls, sometimes reaching 100 knots, occur on the eastern side of the Adriatic constituting a danger to shipping, especially as they often set in with little or no warning.

Note: Simoom is a strong, dry, desert wind that blows in the Sahara, Israel, Jordan, Syria, and the desert of Arabia.

The Caspian Sea and Lake Baikal were formed by the movement of tectonic plates.

Crater Lake, in the U.S. state of Oregon, one of the deepest lakes in the world, was created when ancient Mount Mazama’s volcanic cone collapsed.

Many lakes in North America, including the Great Lakes, were created primarily by glaciers

Atolls and Humans:

The rocky or sandy shores of atolls have been important sites throughout human history. Often, their low-lying elevation has proved perilous.

Atolls are often uninhabited “desert” islands. (Desert does not refer to the islands’ climate, but their “deserted” or uninhabited status.) Many are remote and difficult to reach. In the 20th century, this isolation made them attractive as testing sites for nuclear weapons from the United States, Britain, and France.

The same elements that make atolls popular for nuclear testing also make them attractive to tourists. Atolls are sparsely populated, low-lying islands whose white, sandy beaches and placid lagoons are ideally suited to the tourism industry.

Many atolls, however, have few tourists and are among the world’s underdeveloped countries. Atolls have few natural resources. Soil quality on atolls is very poor, and erosion is a constant threat. Most native residents on atolls practice subsistence agriculture and fishing. Almost all food and fuel is imported, often at great cost.

Statement 1 is incorrect:

Barrier islands are narrow and lie parallel to coastlines.

Statement 2 and 3 are correct:

Some are a part of the continental shelf (continental islands) and made of sediment—sand, silt, and gravel. Barrier islands can also be coral islands, made from billions of tiny coral exoskeletons. Barrier islands are separated from shore by a lagoon or a sound.

They are called barrier islands because they act as barriers between the ocean and the mainland. They protect the coast from being directly battered by storm waves and winds.

One of the striking features of the continental shelf is the presence of submarine canyons which extend to the continental slope. These canyons are ‘steepsided valleys’ cut into the floor of the seas. They are very similar to the gorges found on the continents. Godavari Canyon in front of the Godavari river mouth is 502 metres deep.

One of the reasons for the formation of submarine canyon is underwater landslide. The sediments collected on the continental shelves get dislodged by a storm or a earthquake. The force of these moving sediments erode the slopes as they come down and as a result submarine canyons are carved out.

Both the Statements are correct but Reason is not the correct explanation of Assertion because the reason given explains how surface water of Oceans at the equator not always remain warm due to Upwellings of deep, cold water which reduces the surface temperature of tropical and subtropical sea waters. But the reason nowhere explains how the decrease of temperature of surface water of Oceans towards the poles is not always uniform.

The temperature of the surface water of the oceans varies in much the same way as that of the land surface. This is because insolation is responsible for the varying quantities of heat which are received at different latitudes and in different seasons. Generally, the temperature is higher near the equator and gradually decreases towards the poles. . The mean annual temperatures of about 27°C or higher, are common in tropical seas but there is a general decrease towards the poles where the mean temperature of around 1.8°C are found.

However, the decrease of temperature of surface water towards the poles or increase towards the equator is not uniform because drifting warm water from the tropical seas may move into higher latitudes or vice versa and gives a local increase or decrease of temperature. Upwellings of deep, cold water also reduce locally the surface temperature of tropical and subtropical sea waters.