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Accueil du site → Doctorat → États-Unis → 1995 → MID-TROPOSPHERIC GEOPOTENTIAL HEIGHT PATTERNS AS RELATED TO TEMPERATURE AND PRECIPITATION IN SAUDI ARABIA

University of Nebraska-Lincoln (1995)

MID-TROPOSPHERIC GEOPOTENTIAL HEIGHT PATTERNS AS RELATED TO TEMPERATURE AND PRECIPITATION IN SAUDI ARABIA

KOIIBI, FAHAD MOHAMAD

Titre : MID-TROPOSPHERIC GEOPOTENTIAL HEIGHT PATTERNS AS RELATED TO TEMPERATURE AND PRECIPITATION IN SAUDI ARABIA

Auteur : KOIIBI, FAHAD MOHAMAD

Université de soutenance : UNIVERSITY OF NEBRASKA AT LINCOLN,

Grade : Doctor of Philosophy (PhD) 1995

Résumé
The mid-tropospheric geopotential height patterns and anomalies associated with temperature and precipitation departures from normal in Saudi Arabia were investigated. The mid-tropospheric teleconnection patterns affecting Saudi Arabia and the effect of ENSO’s teleconnection on the precipitation of the country were also examined. This investigation covered the seven month period, November to May. MEPA surface data and NMC Northern Hemisphere octagonal grid 700 mb geopotential height data were used in this study. Various techniques such as compositing analyses, regression analyses and correlation analyses were utilized in this study. It was found that Saudi Arabia experiences below normal temperatures when there are strong positive 700 mb geopotential height anomalies over western Europe and the western Mediterranean, strong negative height anomalies over the Icelandic region, and negative height anomalies over northwestern Asia. Alternatively, when western Europe and the western Mediterranean region experience negative height anomalies and the Icelandic region experiences positive height anomalies, Saudi Arabia experiences above normal temperatures. These patterns control the strength and the location of the Mediterranean trough, which plays an important role in the climate of Saudi Arabia. The trough is strong and well west of the country during the warm months, but it is weaker and just on the western edge of the country during the cold months. The pattern and temporal behavior of the mid-tropospheric waves over the eastern Atlantic Ocean and the western Mediterranean and Europe are related to positive precipitation departures in Saudi Arabia. This pattern and temporal behavior can be described as an eastward progression of a strong trough during the three days preceding a precipitation day in Saudi Arabia. During the precipitation day, this trough is located just west of the country, putting Saudi Arabia under cyclonic activity. An investigation of the teleconnection patterns affecting Saudi Arabia indicates that the centers of action over the eastern Atlantic Ocean and the western Mediterranean and Europe are strongly related to the base point over Saudi Arabia. The effect of ENSO teleconnection on the precipitation pattern in Saudi Arabia is represented in a significant lagged relationship between the SOI and precipitation, especially spring precipitation.

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Page publiée le 30 janvier 2012, mise à jour le 1er janvier 2017