Southern Hemisphere

The catalyzed decomposition of ozone is known to be responsible for the ozone hole (Figure A) that develops in Antarctica each year in September and October, at the end of winter in the Southern Hemisphere. No ozone is generated during the long, dark Antarctic winter. Meanwhile, a heterogeneous reaction occurring on clouds of ice... 

Ozone depletion is by no means restricted to the Southern Hemisphere. In the extremely cold winter of 1994-1995, a similar "ozone hole" was found in the Arctic. Beyond that, the concentration of ozone in the atmosphere over parts of Siberia dropped by 40%. 

The ozone (03) layer aver the southern hemisphere stratosphere in August 2007. The bar at the bottom indicates the color-coding used to indicate the thickness of the layer. The thickness is measured in Dobsons (= 0.01 mm thick). The normal ozone layer for the stratosphere is 360 Dobsons (color coded as green). The ozone "hole" shown in pink is 200-220 Dobsons. The "hole" will increase when another reading is taken in September. 

Mario Molina and Sherwood Rowland used Crutzen s work and other data in 1974 to build a model of the stratosphere that explained how chlorofluorocarbons could threaten the ozone layer. In 1985, ozone levels over Antarctica were indeed found to be decreasing and had dropped to the lowest ever observed by the year 2000, the hole had reached Chile. These losses are now known to be global in extent and it has been postulated that they may be contributing to global warming in the Southern Hemisphere. 

Bigg, E. K., Gras, J. L., and Evans, C. (1984). Origin of Aitken particles in remote regions of the Southern Hemisphere. /. Atmos. Chem. 1, 203-214. 

Fig. 7-4 Cross-section of the northern hemisphere atmosphere showing first-order circulation. The southern hemisphere is a mirror image.

As a result of these factors (wind, Ekman transport, Coriolis force) the surface ocean circulation in the mid-latitudes is characterized by clockwise gyres in the northern hemisphere and the counterclockwise gyres in the southern hemisphere. The main surface currents around these gyres for the world s oceans are shown in Fig. 10-6. The regions where Ekman transport tends to push water together are called convergences. Divergences result when surface waters are pushed apart. 

Thamnolia vermicularis is an arctic-alpine, fruticose, soil-dwelling lichen that enjoys a very wide distribution. The species consists of two chemical strains, one predominantly found in the Northern Hemisphere and the other in the Southern Hemisphere, with most populations from intermediate regions exhibiting intermediate chemical types. Sato (1965) showed that the southern strain accumulates thamnolic acid [403], whereas the northern strain is characterized by two compounds, squamatic acid [404] and baeomycic acid [405]. Populations from Greenland, Novaya Zemlya, and Svalbard exhibited only the northern profile. Two populations from South America exhibited only the southern type, while collections from New Zealand showed nearly pure southern type. 

This chapter deals with taxa whose ranges of occurrence are disjunct between the Northern and Southern Hemispheres. Some of the examples involve taxa with related members whose distributions lit into other categories, some of which have been discussed above. Chrysosplenium, for example, has a distribution that involves disjunctions between Asia and North America, between eastern and western North America, and between the Northern Hemisphere and the Southern Hemisphere. 

Between 1900 and 1950, gastric cancer was one of the major types of cancer in the United States. Its incidence and mortality have decreased sharply since 1950 (41), and the concepts presented in this paper account for this decline. In other parts of the world, including Japan, the mountainous interior regions of Central and Western Latin America, and in Northern and Eastern Europe, as well as in Iceland, gastric cancer remains one of the major cancers. There is a North-South gradient, or South-North in the Southern hemisphere, with greater incidence in more frigid zones. 

In the case when the pendulum path is an ellipse the effect of the earth s rotation is to cause the ellipse to rotate with an angular velocity equal to (—co sin X). As we know, at the poles it is approximately 7.3 x 10 s. In accordance with Equation (3.94), for an observer located at the z-axis above the earth the rotation is clockwise in the northern hemisphere, (A>0), and counterclockwise in the southern hemisphere, (A<0). For example, at the North Pole the direction of the pendulum rotation and the earth are opposite to each other. During swinging the pendulum moves from the point a to the opposite point of the path b, which is shifted at some small distance because of the earth s rotation. Fig. 3.5c. Suppose that the radius of the circle is sq, then the displacement bd during a half period of swinging, Tjl, is... 

A globally based measurement network for atmospheric Hg does not exist. Longterm measurements of TGHg have, however, been performed at some land-based stations. Data from remote marine sites are mainly available from research cruises. Recently, Slemr et al. (2003) compiled TGHg data from a number of permanent stations and oceanic cruises for the northern and southern hemispheres (Figure 2.7). Although the data set is incomplete, a peak in TGHg concentrations seems to have... 

I. Wilkomirsky, M. Sanchez and C. Hecker, eds., Chemical Metallurgy, Proceedings of the IVth Meeting of Southern Hemisphere on Mineral Technology, Concepcion, Chile, Nov. 20-23,1994, Univ. of Concepcion. 

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