الاتجاه العام للغطاء الغيمي واثره على التساقط في العراق : دراسة في جغرافية المناخ == The General Attitude Of The Cloud Cover And Its Impact On Precipitation In Iraq - A Study In Climate Geography
Author name:
مها عيسى توفيق الدلو
Supervisor name:
بدر جدوع احمد المعموري
General topic:
Geography
Specific topic:
Natural Geography
Degree:
Doctorate
University:
University of Baghdad
Language:
Arabic
University location:
Baghdad
First pages:
10T1577 - p.pdf
Abstract:
This study (The General Attitude of the Cloud Cover and Its Impact on precipitation in Iraq ) aims to determine the general direction of low and medium clouds in Iraq during the period of the study between (1988 - 2013) , determine the general direction of the total cloud (N) and low and medium clouds cover (Nh) in order to determine what if the clouds in Iraq have increased in repetition number or decreased during the study period, and then determine the relationship between clouds and rain in Iraq by the statistical relationship.Clouds have a great importance in nature where they are considered as the main distributor of precipitation types on earth and the air in contact with them. They reflect a ratio of about 80% of solar radiation. They also keep the long wave ground thermal radiation from escaping to the external space. The main reason for the formation of these clouds are the depressions that affect them in terms of the number of their frequencies and consequently the frequencies and the types of clouds differ from one season to another and from one area to another. Thus, in this study, the light was shed on the general attitude of the cloud cover to define to what the registration of the frequencies of cloud cover with its amounts and types during the study duration (1988 - 2013), especially that the climatic changes occurring in the world highly influenced the registrations of various climate elements including registrations provide depressions and are highly responsible of forming clouds with their types. As we mentioned before, the clouds and their direction were studied by dividing the study duration into two climatic periods (1988 - 2001) and (2002 - 2013) to show the averages of both periods and the differencebetween them and to identify which clouds registered a more decrease ratio during both periods.The cloud cover is regarded as one of the main indicators to express the amounts of the rains falling over the earth surface, hence the types most affecting the precipitation (rains) were studied, i.e. the low and middle height clouds. Despite that, it was shown that not all types of low and middle height clouds were productive clouds for some types were largely responsible of forming precipitation compared to other types which had no role but very little. It also was shown that there were certain types responsible of rains at the study area, so to achieve this goal of the study, the researcher collected all the hourly data about the types of clouds with respect to the low and middle height clouds, as well as the hourly data related to the cloud cover. They were examined in the form of rainy seasons starting from (September, October, November, December) and ending in (January, February, March, April, May).The study also included the deduction of the relation among the types of clouds, the cloud cover and the collections of rains through the statistical relationship (the correlation coefficient) to show the extend of relationship among them. The analysis during the study showed that there was a decrease in the frequency average of the low and middle height types of clouds with different ratios from one type to another. Also, there was a decrease in the coverage of clouds, especially the types most affecting the amount of rains. Moreover, there was a strong positive relationship with some types of clouds, the cloud coverage and rains, while this relationship was weak and negative with other types of clouds and the cloud coverage.For the study to include the general attitude of the types of clouds, the coverage of clouds and its relation with rains, it was studied in five chapters :
