부산대학교 도서관

In some areas of the world, there are certain patterns of airflow which are created as a result of the interaction between different environmental factors. This study is trying to introduce one of these specific patterns that emerges particularly in closed and semi-closed deserts, especially in the arid and semi-arid areas. This phenomenon is highly influenced by the mountain-plain wind systems and that is defined as "morning cyclone." In addition to "NOAA/AVHRR" satellite images, the ERA-interim reanalysis data are used as the main data in this study. The morning cyclone has been studied in the Taklamakan Desert in the northwest of China, and the Margo Desert in Afghanistan. The common feature of these two deserts is being surrounded by high mountains. This feature, alongside with some climatic characteristics such as air aridity, influences the formation of morning cyclones. The results of this study demonstrate the formation mechanisms of these cyclones. According to these mechanisms, morning cyclones form when the sun rises in the morning, the land surface temperature increases, and the mixed layer grows in mountain-surrounded deserts, while the mountain-plain winds (Katabatic winds) are blowing. As long as katabatic winds are blowing and warming trend continues across the deserts, the morning cyclones continue to exist. However, approaching noon, anabatic winds dominate over the lands and the morning cyclone disappears quickly. In other words, the morning cyclone has a lifetime spanning the hours between sunrise and pre-noon. [ABSTRACT FROM AUTHOR]