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The Earth’s Atmosphere Contents Part 5

Tham khảo tài liệu 'the earth’s atmosphere contents part 5', khoa học tự nhiên, vật lý phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 188 Chapter 7 Atmospheric Circulations Notice in Fig. 7.23 that as the Gulf Stream moves northward the prevailing westerlies steer it away from the coast of North America and eastward toward Europe. Generally it widens and slows as it merges into the broader North Atlantic Drift. As this current approaches Europe part of it flows northward along the coasts of Great Britain and Norway bringing with it warm water which helps keep winter temperatures much warmer than one would expect this far north . The other part flows southward as the Canary Current which transports cool northern water equatorward. In the Pacific Ocean the counterpart to the Canary Current is the California Current that carries cool water southward along the coastline of the western United States. Up to now we have seen that atmospheric circulations and ocean circulations are closely linked wind blowing over the oceans produces surface ocean currents. The currents along with the wind transfer heat from tropical areas where there is a surplus of energy to polar regions where there is a deficit. This helps to equalize the latitudinal energy imbalance with about 40 percent of the total heat transport in the Northern Hemisphere coming from surface ocean currents. The environmental implications of this heat transfer are tremendous. If the energy imbalance were to go unchecked yearly temperature differences between low and high latitudes would increase greatly and the climate would gradually change. 90 180 90 0 60 60 30 0 30 60 90 180 90 0 7 8 9 FIGURE 7.23 Average position and extent of the major surface ocean currents. Cold currents are shown in blue warm currents are shown in red. Names of the ocean currents are given in Table 7.2. Longitude 90 TABLE 7.2 Major Ocean Currents 1. Gulf Stream 9. South Equatorial Current 17. Peru or Humbolt Current 2. North Atlantic Drift 10. South Equatorial Countercurrent 18. Brazil Current 3. Labrador Current 11. Equatorial Countercurrent 19. Falkland Current 4. West .