4. Climate.

Map Questions.

1. Which parts of North America are crossed by the Arctic Circle and the Tropic of Cancer?

2. How many degrees distant from the Equator is the Isthmus of Panama?

3. In which temperature zones does North America lie?

General Characteristics of Climate. North America stretches almost completely across the Northern Hemisphere. The northern coasts of Greenland extend beyond parallel 80°N, while the Isthmus of Panama is only a few degrees distant from the Equator. The polar islands and the coast facing the Arctic Ocean lie in the frigid zone, the greater part of the continent in the temperate zone, the southern part and the Antilles in the torrid zone.

In no part of the world are the arctic and tropical waters so close to each other, the distance from the Hudson Bay to the Gulf of Mexico being less than 3,000 kilometers. The absence of mountains in the north allows cold winds from the Arctic region to travel far inland, causing frost and snow in winter as far south as the Gulf of Mexico. But, as if to make up for this, the absence of mountains in the south permits the tropical winds to penetrate far north. The weather in North America is therefore very unstable, with frequent changes of temperature in winter.

There sometimes occur cyclones in summer and autumn. These are violent storms with pouring rain and thunder. They sweep away everything in their path, tearing down buildings, rooting up trees, killing people.

The influence of warm ocean currents is not so great in North America as in Europe. The warm current running along the northwestern coast influences only a narrow strip of the coastal belt as far as the first range. Further south along the Pacific coast flows a cool current. The Gulf Stream, after flowing out of the Gulf of Mexico, is soon driven eastward, and the eastern coast of America is washed by the cold Labrador Current. Because of this the tundra in the eastern part of North America extends further south than in either Europe or Asia.

On the whole, the climate of North America is more rigorous than that of Europe in the same latitudes.

Vocabulary

frigid zone- зона замерзания

torrid zone-

to root up trees-с корнем вырывать деревья

current-течение

rigorous-суровый

Questions

1.What is the distance from the Hudson Bay to the Gulf of Mexico?

2.What allows cold winds from the Arctic Region to travel as far south as the Gulf of Mexico causing frost and winter?

3. How can you characterize the weather in North America?

4.What sometimes occurs in summer and autumn?

5. Is there any influence of warm ocran current in North America?

6.What is the difference between the climate of North America and that of Euorope in the same latitudes?

Climatic Regions. The Arctic islands and coast-lands and the northern part of Labrador have a climate of the arctic type. Winters are long and frosts severe, the average January temperature being about 30°C below zero. Nowhere, however, ice-clad Greenland included, is the temperature as low as in the 'Cold Pole' region of North-Eastern Siberia. It is cold in the interior of Greenland even in summer, the average July temperature being from 0° to 10O С below zero.

The northern part of the Pacific coast in the temperate zone receives much rain (from 1,000 to 2,000 mm yearly, and more) brought by the prevailing westerly winds blowing from the Pacific. The sky is usually covered with clouds, the land wrapped in mist. Sunny days are very rare. Here everlasting autumn reigns. The annual range of temperature is small, as winters are not very cold (the January isotherm along the coast is 0° C) and summers not very hot. The climate here is of the maritime type.

The climate is different on either side of the Cordilleras. Oceanic influences from the Pacific do not reach the interior, and for this reason the greater part of North America has a continental climate. The weather is unsteady, however, and there often occur thaws. Spring brings hot weather immediately. At the beginning of summer, however, the temperature may fall again, which is very dangerous for crops. In summer it is often very hot.

The rainfall is not very heavy, but it increases towards the Atlantic Ocean.

Especially dry and continental is the climate on the plateaus between the Cordillera ranges, where there are sharp differences between day and night temperatures. The annual range of temperature here is over 20—30° C. The sky is usually cloudless. The annual rainfall is hardly 200 mm. Here the climate is of the desert type.

The Pacific coast north of the peninsula of California and the Gulf of Mexico coast-lands enjoy a subtropical climate. On the Pacific coast it is of the Mediterranean type found in Europe. Rainfall is small. Most of the rain falls in winter. Summers are warm and dry. Rainfall is much heavier on the Gulf coast and in Florida, reaching from 1,000 to 2,000 mm a year. Winters there are short and warm. The cold Arctic winds sometimes reach these regions, however, causing frosts. Summers are long and hot. There often occur cyclones and thunderstorms.

Central America south of the Tropic of Cancer and the Antilles enjoy a wet tropical climate with high temperatures throughout the year and a heavy rainfall.