By what process does North Atlantic Central Surface Water become North Atlantic Deep Water?

Question

BlackTom AI · Accepted Answer

The question asks: By what process does North Atlantic Central Surface Water become North Atlantic Deep Water?

Option analysis:
- Provided answer: 'Cooling and freshening.' This combination is not consistent with the well-established mechanism for NADW formation. Deep water formation requires the water to become denser, which results from cooling (lower temperature) and/or higher salinity (greater density). Freshening (a decrease in salinity) would reduce density and inhibit deep-water formation rather than promote it. Therefore, 'Cooling and freshening' misidentifies the salinity aspect and would not explain the formation of NADW.

Contextual explanation: In the North Atlantic, surface waters cool as they move toward higher latitudes. If they are sufficiently saline (often due to evaporation and brine rejection from ice formation elsewhere), cooling increases density enough that the water sinks, creating North Atlantic Deep Water. The key density-increasing factors are temperature decrease (cooling) and salinity increase (not freshening). Thus the correct description would involve cooling plus an increase in salinity, not freshening.

Why the idea of 'cooling and freshening' is misleading: Cooling lowers temperature, which tends to increase density; but freshening lowers salinity, which lowers density. Since NADW formation depends on a density increase to drive sinking, freshening would counteract this process. In oceanography, the common pairing is cooling with higher salinity (or at least not reduced salinity) to produce the dense water that sinks.

If you were given multiple-choice options, you would evaluate each one for whether the stated factors increase water density. Any option proposing a density-reducing factor (like freshening) paired with cooling would still be incorrect, while one stating cooling plus increased salinity or at least not decreased salinity would be the correct mechanism.

In summary, NADW forms primarily due to cooling of Atlantic surface waters combined with relatively high salinity that increases water density; freshening would inhibit the formation process rather than enable it.

CLMTGR5001_002_2025_3 - Dynamics of Climate Variability and Chan PRACTICE QUIZ: Week 7 Lecture 3

By what process does North Atlantic Central Surface Water become North Atlantic Deep Water?

查看解析

登录即可查看完整答案

类似问题

The thermohaline circulation transports heat from one hemisphere to another. In which direction does this energy flow?

Deep Water forms in the North Atlantic because winter storms make surface waters more saline

The thermohaline circulation transports heat further north than the wind-driven circulation.

The thermohaline circulation transports heat in the same direction as the wind-driven circulation in the Northern Hemisphere.

The thermohaline circulation is the largest ocean current by ocean heat transport.

The thermohaline circulation transports heat in the same direction as the wind-driven circulation in the Southern Hemisphere.

The thermohaline circulation transports heat in the same direction as the wind-driven circulation in the Southern Hemisphere.

更多留学生实用工具

考试浏览器助手

风格化写作助手

论文查重助手

文献引用助手

课堂转译助手

课堂笔记助手

Quiz搜索助手

学校历年真题

智能刷题助手

智能匹配练习

希望你的学习变得更简单