Oceanic Circulation

Rate of Removal of CO2 from Atmosphere Depends on Ocean Circulation Ocean circulation has a major impact on the distribution of carbon between the ocean and the atmosphere. Figure 15.20 is an extension of the two-box model used in Figure 15.16. The CO2 uptake is very rapid at first but... 

Water is omnipresent on the earth. Constant circulation of water from the ocean to the atmosphere (evaporation) and from the atmosphere to land and the oceans (precipitation, mnoff, etc) is generally known as the hydrologic cycle (see Fig. 1) (1 2). Within the hydrologic cycHc, there are several minor and local subcycles where water is used and returned to the environment. 

Momentum is mostly transferred from the atmosphere to the ocean, having the effect of driving the ocean circulation through the production of a wind-driven flow. Of course, the resultant flow carries heat and water, so contributing to fluxes of these quantities to the atmosphere in ways that would not have occurred without the establishment of the wind-driven circulation in the first place. 

Y. Nozaki, in Deep Ocean Circulation, Physical and Chemical Aspects, ed. T. Teramoto, Elsevier, Amsterdam, 1993, pp. 83-89. 

Joly observed elevated "Ra activities in deep-sea sediments that he attributed to water column scavenging and removal processes. This hypothesis was later challenged with the hrst seawater °Th measurements (parent of "Ra), and these new results conhrmed that radium was instead actively migrating across the marine sediment-water interface. This seabed source stimulated much activity to use radium as a tracer for ocean circulation. Unfortunately, the utility of Ra as a deep ocean circulation tracer never came to full fruition as biological cycling has been repeatedly shown to have a strong and unpredictable effect on the vertical distribution of this isotope. 

Cycles established as statistically real are the familiar annual and diurnal radiation/temperature cycles, a quasibiennial (about every 2 years) fluctuation in various climatic elements, and the interannual variability of June rainfall in northern India. The first merely means that winters are cooler than summers and nights are cooler than days. Examples of the second cycle include Midwestern rainfall, a lengthy temperature record from central England, and winds over the western Paciflc and eastern Indian Ocean. According to Campbell et al (19), the third cycle may be a response to the monthly solar-lunar tide and its influence on the monsoon circulation. 

---