E 60e 90e 120e 150e 180 150w 120w 90w 60w 30w

Fig. 1.19 Annual mean sea surface temperature anomaly (°C), deviation from the zonal mean. See color plate section.

Atlantic Basins. Another major factor is the wind-driven gyres. The anticyclonic gyre in the subtropical basin brings relatively cold water from the mid latitudes and thus contributes to the low temperature in the eastern basins.

Cyclonic and anticyclonic gyres, shown in Figure 1.2, are the major players in setting water properties in the upper ocean. Cyclonic gyres in the subpolar basins bring relatively warm water to the eastern part of the subpolar basins, thus maintaining a relatively warm surface temperature. On the other hand, cold water brought by the cyclonic gyres from the north creates the regime of cold surface water in the western part of the subpolar basins. In addition, the strong cold and dry air from the Eurasian continent must contribute to the low surface temperature north of Japan. Similar, there is a narrow band of low temperature around the eastern coast of Canada and northeastern coast of the USA. As a result, over the high-latitude band in both the North Pacific and North Atlantic Oceans, the sea surface temperature near the eastern boundaries is substantially warmer than that near the western boundaries (Fig. 1.19).

Second, there is a major contrast between the Atlantic and Pacific Oceans. Sea surface temperature in the eastern and middleparts of the northern North Atlantic Ocean is about 5°C warmer than the zonal mean temperature. In comparison, sea surface temperature along the eastern boundary of the northern North Pacific Ocean is only slightly warmer than the zonal mean temperature. The dramatic difference in the zonal sea surface temperature distribution

Was this article helpful?

0 0

Post a comment