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التنبؤ بالتساقط باستخدام بيانات الغطاء الغيمي في العراق : دراسة في جغرافية المناخ == Forecasting The Precipitation By Using Cloud Cover Data In Iraq Study In The Geography Of The Climate
Author name:
سالار علي خضر الدزيي
Supervisor name:
نعمة محسن لفتة الفتلاوي
General topic:
Geography
Specific topic:
Geography
Degree:
Doctorate
University:
University of Baghdad - College Of Literature
Language:
Arabic
University location:
Baghdad
First pages:
10T1458 - p.pdf
Abstract:
The aim of this study is (forecasting the precipitation by using cloud cover data in Iraq). To achieve this goal, the properties of low, medium and high clouds affecting Iraq mounted (27) types are studied through their diffusion percentage (coverage), base height, types and the relation between each of these properties and rainfall with its five shapes (drizzle - rains - snows - heavy showers and thunderstorms). for eight climatic stations from Iraq (Mosul, Kirkuk, Baghdad, Rutba, Al - Hay, Diwayniya, Nasiriya and Basra).The research results were reached the following points : - Concerning the clouds' properties like their diffusion percentage and base height, the results have proved that the season difference affects these two properties greatly where the diffusion percentage of the clouds increases during winter and decreases during spring and autumn, also the base height of the clouds decreases during winter and increases during spring and autumn. - As to the nine types of low clouds, it is found that they do not appear evenly for some types appear more than the others.Generally, the types of low clouds that hold the characteristics of the layered clouds and the accumulated clouds are the most apparent types in Iraq weathers such as the layered accumulation clouds on one hand. The appearance of types with the layered shapes increases during cold months (winter), whereas the appearance of types with accumulated shapes increases during moderate months (spring and autumn) on the other hand. - For types of medium clouds, their appearance average also varies according to their types. The appearance of the layered types increases during winter and the appearance of the accumulated types increases during spring and autumn, too. - The high clouds are characterized with their all nine types being at the peak of appearance averages during spring, autumn then winter.The results, related to the relation between rainfall and its types with the clouds' base height, prove that there are heights for clouds' bases contribute largely in forming rainfall and its shapes Vs the non contribution of other heights except with too little rates of rainfall. Regarding the relation nature between rainfall and its shapes with low and medium clouds, it is clear that not all types of low and medium clouds are unproductive for some types are greatly responsible of forming rainfall compared to other types thathave a too little role, on one hand. It is found that there are certain types of clouds responsible of certain types of rainfall and its shapes, on the other hand. In order to complete the picture concerning this subject, the analytic method of flat and upper maps air for the two pressure levels (850 - 500) Millibar is used to define the types of the flat and upper pressure system responsible of forming the types of clouds and their height forming in tum different rainfall shapes. The results have proved the existence of a certain order for those different pressure systems during the formation of a certain shape of clouds and rainfall. This order is exposed to change during the occurrence of another shape of rainfall. These changes can be used for future forecast of various rainfall shapes. In addition, T t/> gram diagram is used to define the thickness and height of chosen types of low and medium clouds functionally through following ·up the temperature of air and dew point.
