Asia Essay Research Paper AsiaAsia is the — страница 3

  • Просмотров 531
  • Скачиваний 9
  • Размер файла 24
    Кб

supercontinent known as Pangaea. During the Triassic Period, Pangaea split apart into the northern land mass of Laurasia (from which North America, Europe, and northern Asia later developed) and the southern land mass of Gondwanaland (from which India and the continents of the Southern Hemisphere later developed). A large sea called Tethys separated the two landmasses. By the end of the Jurassic Period, Gondwanaland fragmented, and the Indian plate began a northeastward movement. It eventually collided with and was drawn under the edge of the Eurasian plate, and in the process Tethyan sediments were deformed and uplifted to form the Himalayas, Tibetan Plateau, and other high mountains of southern Asia. The African plate moved northward and collided with Eurasia to thrust up the

European Alps and the mountains of Asia west of the Himalayas. Much later, probably during the Miocene Epoch, rifting and seafloor spreading created the Red Sea and the Gulf of Aden, and Arabia split away from Africa to form a separate plate. Earth movements occur today in the Indonesian, Japanese, Philippine, and other Pacific island arcs; in these areas there is widespread seismic and volcanic activity, attesting to the geological instability of the region. Climate Three broad climatic realms may be distinguished in Asia. They are: monsoon Asia, dry Asia, and cold Asia. 1. Monsoon Asia The climate of South, Southeast, and East Asia is strongly influenced by the immensity of the Asian land mass, the barrier presented by its great highland core, and the monsoon wind system. In

summer, the continental interior of Asia heats up rapidly as a result of increased isolation as the overhead sun moves toward the Tropic of Cancer. Warm air above the heart of Asia rises and creates low-pressure centers. The air pressures above the Pacific and Indian oceans are relatively high. Consequently, strong, moisture-laden winds are drawn inland from the oceans into the low-pressure areas of Asia, bringing heavy rainfall wherever they are forced to rise up over low hills, mountains, or other topographic obstacles. The summer monsoon in India interrupts a very hot, dry spell. Elsewhere in Southeast and East Asia the break is not as dramatic, but rainfall in all of monsoon Asia is concentrated in the summer months. In the coastal region of East Asia, tropical cyclones

(typhoons) bring additional precipitation and devastating winds. In winter, the land surface in the interior of Asia cools off more rapidly than the surrounding oceans. As a result, cold descending air currents over the heart of Asia generate high-pressure centers facing the relatively low-pressure zones over the Indian and Pacific oceans, where temperatures are higher. From October to about April, cold, dry, continental winds blow offshore from inland Asia. This is the season of the winter monsoon. Places exposed to the monsoons are warmer in summer and colder in winter than places in corresponding latitudes not under their influence. They are also, for the most part, the wettest parts of Asia. Within this large monsoon area, important temperature differences exist between north

and south. An equatorial climate predominates over much of Indonesia and Malaysia; average annual temperature is about 70 degrees F and average annual rainfall more than 80 in. North of the equatorial region is a tropical monsoon area, in which summers are hot and humid (average temperatures over 80 degrees F) and winters cool (50 degrees F) and dry. Rainfall is more than 50 in). Climates in the rest of monsoon Asia range from warm temperate in central China and southern Japan to cool temperate in northern China and Japan. Similarly, the length of the growing season, which is the period between killing frosts in the warm half of the year, decreases gradually from almost a full year in Indonesia to about four months in China’s northeast. 2. Dry Asia Parts of Southeast Asia,

Central Asia, and Mongolia have a wide range of dry climates that range latitudinally from the tropical deserts of the Arabian Peninsula in the west to the subtropical steppe climate present in Iran and Afghanistan and the mid latitude steppe and deserts of Mongolia and northern China. Rainfall varies from a low of less than 1 in in parts of the Gobi Desert to 8 in in Central Asia. Throughout this belt, rainfall is extremely unpredictable. The eastern coastal fringe of the Mediterranean Basin (the Levant) has a typical Mediterranean climate and receives rain in winter; average annual precipitation along this Western edge of dry Asia is about 20 in. 3. Cold Asia Most of Asian Russia has a cold climate. The southern regions have a subarctic climate, where summers are mild (70