Daily Quiz: UPSC Prelims Marathon – December 8

• A tropical marine climate is usually experienced by islands and coastal areas 10° to 20° north or south of the equator.
• The ocean is the main influence in creating the tropical marine climate.
• There are two main seasons: the wet season and the dry season. The annual rainfall is 1000 to over 1500 mm. The temperature ranges from 20°C to 35°C.
• The trade winds blow all year round and are moist, as they pass over warm seas.

Factors affecting climate:

Distance from the sea (Continentality):The sea affects the climate of a place. Coastal areas are cooler and wetter than inland areas. Clouds form when warm air from inland areas meets cool air from the sea.  The centre of continents are subject to a large range of temperatures.  In the summer, temperatures can be very hot and dry as moisture from the sea evaporates before it reaches the centre of the land mass.

Direction of prevailing winds:Winds that blow from the sea often bring rain to the coast and dry weather to inland areas.

The shape of the land (‘relief’):Climate can be affected by mountains. Mountains receive more rainfall than low lying areas because as air is forced over the higher ground it cools, causing moist air to condense and fall out as rainfall.The higher the place is above sea level the colder it will be.  This happens because as altitude increases, air becomes thinner and is less able to absorb and retain heat. That is why you may see snow on the top of mountains all year round.

Statement 1 and 2 are correct:

El Niño is a climate pattern that describes the unusual warming of surface waters in the eastern tropical Pacific Ocean. El Nino is the “warm phase” of a larger phenomenon called the El Nino-Southern Oscillation (ENSO).

El Niño has an impact on ocean temperatures, the speed and strength of ocean currents, the health of coastal fisheries, and local weather from Australia to South America and beyond. El Niño events occur irregularly at two- to seven-year intervals. However, El Niño is not a regular cycle, or predictable in the sense that ocean tides are.

During an El Niño event, westward-blowing trade winds weaken along the Equator.These changes in air pressure and wind speed cause warm surface water to move eastward along the Equator, from the western Pacific to the coast of northern South America.

These warm surface waters deepen the thermocline, the level of ocean depth that separates warm surface water from the colder water below. During an El Niño event, the thermocline can dip as far as 152 meters (500 feet).

This thick layer of warm water does not allow normal upwelling to occur. Without an upwelling of nutrient-rich cold water, the euphotic zone of the eastern Pacific can no longer support its normally productive coastal ecosystem. Fish populations die or migrate. El Niño has a devastating impact on Ecuadorian and Peruvian economies.

Statement 3 and 4 are incorrect:

El Niño also produces widespread and sometimes severe changes in the climate. Convection above warmer surface waters bring increased precipitation. Rainfall increases drastically in Ecuador and northern Peru, contributing to coastal flooding and erosion. Rains and floods may destroy homes, schools, hospitals, and businesses. They also limit transportation and destroy crops.

As El Niño brings rain to South America, it brings droughts to Indonesia and Australia. These droughts threaten the region’s water supplies, as reservoirs dry and rivers carry less water. Agriculture, which depends on water for irrigation, is threatened.

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.

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.

A cliff is a mass of rock that rises very high and is almost vertical, or straight up-and-down. Cliffs are very common landscape features. They can form near the ocean (sea cliffs), high in mountains, or as the walls of canyons and valleys. Waterfalls tumble over cliffs.

Cliffs are usually formed because of processes called erosion and weathering. Weathering happens when natural events, like wind or rain, break up pieces of rock. In coastal areas, strong winds and powerful waves break off soft or grainy rocks from hardier rocks. The harder rocks are left as cliffs.