Carbon dioxide concentration variation

Nakazawa, T., Murayama, S., Miyashita, K., Aoki, S. and Tanaka, M. (1992). Longitudinally different variations of lower tropospheric carbon dioxide concentrations over the North Pacific Ocean, Tellus, Ser. B, 44,161-172. 

The primary purpose of this section has been to show the possibilities for using density and area profile data to aid in the better understanding of gas-carbon reactions. In order to determine specific reaction rates and carbon dioxide concentrations at given penetrations, it has been necessary to make assumptions which can only be approximations to the truth. Several major anomalies in the results have been found, however. The calculated concentrations of carbon dioxide at the external surface of rods reacted at 1200 (Table VI) and 1305° are not in agreement with the known carbon dioxide concentrations. Clearly, more information is required on the variation of Deir with temperature and its variation with porosity produced at different reaction temperatures. It is feasible that at high temperatures, considerable porosity may be produced without increasing Deo to such a marked extent as found at 900°. Another anomaly is the non-uniformity of reaction found at 925°, when it would be expected that the reaction should be in Zone I. The preliminary assumption of a completely interconnecting pore system may not be valid. It should also be noted that neither the value of K in Equation (75) nor the low-temperature activa-... 

Figure 8.1 Annual variation in atmospheric carbon dioxide concentration as recorded at the Mauna Loa Observatory, Hawaii.

The definition is named as the normahzed variation (NMV), which shows the year-to-year changes relative to the mean amount. The application of this definition to the annual changes of the observed carbon dioxide concentration at Mauna Loa [5] was made and shown in Fig. 1. 

We have to emphasize that the correct prediction of the future COz concentrations is one of most important tasks of atmospheric science at present. This is explained by the fact that the C02 content of our atmosphere regulates, among other things, the radiation balance of the Earth-atmosphere system by absorbing infrared radiation emitted by the surface. Thus, we cannot exclude the possibility that the increase of the carbon dioxide concentration may cause inadvertent climatic variations in the future (see Chapter 6). 

FIGURE 17.17 Yearly variation of carbon dioxide concentration at Manna Loa, Hawaii. The general trend clearly points to an increase of carbon dioxide in the atmosphere. This trend has continued in 1994 the CO2 concentration reached 380 ppm. 

Sparling and Alt (1966) have measured carbon dioxide concentrations in the atmosphere of several Ontario woodlands with an infrared gas analyzer. They found little evidence of seasonal variation in the concentration of carbon dioxide. Measurements over 24-hr periods revealed the existence of high concentrations, frequently exceeding 500 parts per million at night during midsummer. The high concentrations dropped rapidly at sunrise. These workers were not able to confirm the existence of the extreme stratification of carbon dioxide which had been reported by earlier workers. 

The correlation between surface temperature and the isotopic composition of snow forms the basis of ice core paleothermometry, a spectacular example of which is the record of the Vostok ice core (Fig. 12). This record has now been extended out to approximately 450,000 years. It is a record of oxygen and deuterium isotope concentrations in ice originally precipitated as snow and a record of methane and carbon dioxide concentrations in trapped gases as well as other trace elements recorded by the contamination of ice with atmospheric dust particles. The oxygen and deuterium isotope results corroborate the variations observed in the oxygen isotope record of deep sea cores and... 

It has been suggested that the Hatch and Slack pathway is a modification of the Calvin cycle of advantage to plants growing in dense stands of tropical vegetation where the carbon dioxide concentration may be reduced to a very low level. The reduction of atmospheric CO2 concentration which has occurred since the evolution of photosynthetic reactions may also have contributed to the selection of this reaction sequence. The discovery of the Hatch and Slack pathway, although it is not yet fully authenticated, has demonstrated the possible existence of photosynthetic reactions other than the conventional Calvin cycle and suggests that other and as yet undiscovered variations on the photosynthetic theme may exist. 

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