The question lies within the province of the study of atmospheric angular momentum, an area Czarnetzki became interested in as an offshoot of another project.

Both the earth and the atmosphere are rotating, but not necessarily at the same speed. If the movement of the atmosphere were due simply to the drag from the underlying surface, the atmosphere, at best, would only keep pace with the rotating earth. As it turns out, in some places the atmosphere may be rotating faster than the earth; in others the earth may be moving more quickly. Overall, the earth-atmosphere system must conserve the total angular momentum.

One of the most significant components of the system that facilitates the exchange of angular momentum is the Rocky Mountains. For several reasons the Rockies act to slow down the earth's rotation: their north-to-south orientation, their height, the strong winds crossing the mountains, and the fact that east of the Rockies the air is frequently cold and dry, while west of the range the air is likely to be warm and wet. The gradient of mass across the Rockies leads to a torque on the earth that can either increase or decrease its rotation rate depending upon the mass distribution. Any change in rotation rate for the earth, however, is accompanied by a compensating change in the atmosphere's rotation rate.

The Rockies, although a major factor, are not the only one responsible for variations in the earth's rotational speed. Other contributing factors are the Andes Mountains, the Tibetan plateau, and to a lesser extent, the Alps and the oceans. Also important to the exchange is the friction of winds that blow against the oceans and land masses. However, the pressure torque of specific weather events on the Rocky Mountains can produce a force stronger than friction. This happens when low pressure systems develop and move to the east of the mountains, causing the weight of the atmosphere on the west side to exceed the weight on the east side and thereby producing a push on the Rockies in an eastward direction.

Although scientists have been aware of the phenomenon of atmospheric angular momentum exchange for some time, recent advances in technology have made it possible to attain a more refined idea of cause and effect.
cont.

An understanding of how the earth and its atmosphere maintain a balance will give scientists insight into global winds and climate change. This, in turn, has implications for shorter term weather forecasts, the improved accuracy of which many would welcome. 

Czarnetzki plans to submit the case study of his application of wavelet analysis to the Journal of the Atmospheric Sciences. Following is a selected listing of his publications related to the work discussed above, as well as his E-mail address.

Czarnetzki, A.C. (1997). Regional mountain torque estimates over the Rocky Mountains in lee cyclones. Journal of the Atmospheric Sciences, 54, 1986-1997.

Czarnetzki, A.C. (1997). Use of contrast-enhanced infrared imagery to track a mesoscale wave disturbance. Iowa Technical Journal, 5(1), 6-10.

Czarnetzki, A.C. (1997). Using a school based observing network to analyze a mesoscale wave disturbance. Proceedings of the Sixth Symposium on Education, 3-4 February, 1997. Long Beach, CA: American Meteorological Society, pp. 27-28.

Czarnetzki, A.C. (1996). The nonlocal approach to determining atmospheric stability. Iowa Technical Journal, 4(3), 27-32.

Czarnetzki, A.C., & Johnson, D.R. (1996). The role of terrain and pressure stresses in Rocky Mountain lee cyclones. Monthly Weather Review, 124(4),553-570.

Moore, J.T., Czarnetzki, A.C., & Market, P.S. (in press). Heavy precipitation associated with elevated thunderstorms formed in a convectively unstable layer aloft. Meteorological Applications. 

alan.czarnetzki@uni.edu