Atmospheric circulation patterns

In this chapter, we discuss paleoaltimetric application of stable isotopes in fossils. Fossils share some features of other stable isotope proxies, for example in their link to atmospheric circulation patterns and meteoric water compositions. However they differ in other key respects, for example in their link to biology, and in their preservation of seasonal isotope variations, reflecting seasonal climate. These variations complicate some interpretations, but also provide alternative approaches to constrain elevations. 

What is the relationship between the atmospheric circulation patterns and the deep circulation Fluid planets are in many ways more complex than the solid planets, in that the atmospheric circulation patterns have some relationship—greater or lesser—to deep circulations. How the coupling occurs in the giant planets of our solar system, and the strength of the coupling, remain unresolved. 

Amundson R., Chadwick O. A., Kendall C., Wang Y., and DeNiro M. (1996) Isotopic evidence for shifts in atmospheric circulation patterns during the late Quaternary in mid-North America. Geology 24, 23-26. 

Street-Perrott F. A. and Roberts N. (1983) Fluctuations in closed-basin lakes as an indicator of past atmospheric circulation patterns. In Variations in the Global Water Budget (eds. F. A. Street-Perrott, M. Berman, and R. Ratchliffe). Reidel, Dordrecht, pp. 331-346. 

Many features of atmospheric chemical transport can be inferred by inspection of the global-scale atmospheric circulation pattern. The west-to-east movement of industrial chemicals, such as acid rain precursors, is a familiar example in the midlatitudes of the Northern Hemisphere. Of course, these belts of wind, such as the midlatitude westerlies, are subject to modification on a smaller scale by a variety of local and regional conditions. For example, a wind rose from Chicago (Fig. 4-14) shows that despite the dominant southwesterly direction of the wind, wind from other directions also occurs. To explain such departures from the average global circulation pattern, atmospheric processes on smaller scales must be considered. 

Matthaus, W., Schinke, H., 1994. Mean atmospheric circulation patterns associated with major Baltic inflows. Deutsche Hydrographische Zeitschrift, 46, 321-339. 

More recent investigations on the mean atmospheric circulation patterns have shown that there are typical circulation patterns that trigger MBls and are necessary for their occurrence (Matthaus and Schinke, 1994). One of the basic conditions linked to major events is, on average, a mean continuous increase in wind speed from westerly directions over several weeks as, for instance, very distinctly observed in 1951 (Wyrtki, 1954) and 1993 (Matthaus and Lass, 1995). This increase begins about 2 weeks before the main inflow period and reaches maximum values on the day before the overflow of water with salinities >17 psu across the Darss Sill. The higher the mean wind speed and its duration during the main inflow period, the stronger the inflow. 

While mean atmospheric circulation patterns — the static element of the circulation in causing MBls — represent the large-scale conditions forming the guideway for quickly passing depressions, the dynamic element, consisting of the sequence of depressions moving over the area, represents the local conditions as causal factors of MBls. 

As Earth warms, climate changes are expected to occur. More water will evaporate from the oceans. More moisture in the atmosphere will result in more frequent violent storms— hurricanes, cyclones, and heavy monsoons. Because of disruptions to global atmospheric circulation patterns, some areas of Earth will become much wetter, while other areas will become much drier. 

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