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Accueil du site → Doctorat → États-Unis → 1989 → Temporal and spatial climatic relationships between the Great Plains and North Africa

University of Nebraska - Lincoln (1989)

Temporal and spatial climatic relationships between the Great Plains and North Africa

Mahmoud, Ali Ahmad Yousef

Titre : Temporal and spatial climatic relationships between the Great Plains and North Africa

Auteur : Mahmoud, Ali Ahmad Yousef

Université de soutenance : University of Nebraska - Lincoln

Grade : Doctor of Philosophy (PhD) 1989

Résumé
Paleoclimatic and modeling studies dealing with the climatic conditions during a past and future warmer Earth have shown an inverse climatic relationship (wet/dry) between the Great Plains and North Africa. This study used monthly mean temperatures and monthly total precipitation during the 30-year period from 1951 to 1980 to determine if there are, indeed, climatic relationships between the Great Plains and North Africa.^ The annual amounts of precipitation are used to divide each region into subregions of which there are ten in North Africa and three in the Great Plains. Precipitation data are also used to calculate the correlation coefficients between subregions in the Great Plains and North Africa. Correlation coefficients between temperature and precipitation among stations are also calculated.^ There are indications of negative relationships between northern and southern subregions in both the Great Plains and North Africa, but direct as well as indirect climatic relationships exist between the Great Plains subregions and North African subregions. In general, climatic relationships between the Great Plains and North African subregions are weak and insignificant. This conclusion is in contrast with the conclusions obtained from paleoclimatic and modeling studies.^ Indirect climatic relationships between the Great Plains and North Africa were experienced during the Great Plains drought of 1952-1956 and during the Sahel drought of 1968-1973. The persistance of certain patterns of the general circulation may be the main cause of these droughts. Changes in the circulation patterns over the Pacific and Atlantic Oceans (due to the effect of SSTs) were associated with changes in the circulation patterns over the Great Plains and North Africa. These changes may produce climatic teleconnections between the Great Plains and North Africa.

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Page publiée le 17 septembre 2010, mise à jour le 30 janvier 2018