Causes and effects of atmospheric interannual variability: progress report to National Science Foundation
Date
1977-06
Authors
Reiter, Elmar R., author
Department of Atmospheric Science, Colorado State University, publisher
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Abstract
During the present grant period we examined in some detail the 24-day vacillation in the atmospheric energy cycle. We arrived at the conclusion that this cycle is tied to baroclinic instabilities and to the amplification of cyclonic disturbances upon which feed the planetary wave modes. We also examined cases of sudden stratospheric warming. They are generally characterized by prolonged decreases in hemispheric zonal available potential energy, by the development of a blocking ridge over the Gulf of Alaska and by a tendency towards below-normal temperatures over the Eastern United States. A feasibility study of hemispheric monthly precipitation anomalies revealed that large anomalies, indeed, exist simultaneously and with same sign over the continents of the northern hemisphere. From this conclusion the importance of the hydrological cycle in atmospheric variability studies has to be emphasized again. Another source of atmospheric interannual variability has been identified in the sensible and latent heat transfers between ocean and atmosphere. The 24-day vacillation appears to be influenced by these heat transfers, especially in regions with large sea surface temperature (SST) anomalies. The SST anomalies in the North Pacific between 40 and 50°N appear to be caused by fluctuations in the water transport around the Pacific gyro. This transport, in turn, seems to respond to long-term and large-scale fluctuations in the v-component of the trade winds in both hemispheres. Such fluctuations also appear to influence the global mean annual temperature, perhaps due to variations in the release of latent heat within the intertropical convergence zone.
Description
Progress report for 1 October 1976-30 June 1977.
Rights Access
Subject
Ocean-atmosphere interaction
Climatic changes
Atmospheric circulation
Precipitation (Meteorology)
Atmosphere -- Research