ORIGINAL PAPER A composite analysis of the morning cyclone in two Asian deserts Alireza Saeedi 1 & Faramarz Khoshakhlagh 1 Received: 17 August 2017 /Accepted: 22 August 2018 # Springer-Verlag GmbH Austria, part of Springer Nature 2018 Abstract 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 Bmorning cyclone.^ In addition to BNOAA/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. 1 Introduction The atmospheric and climate system analysis in regional and local scales in arid and semi-arid areas is essential for the study of the environmental landscapes and eolian landforms, and also land-use planning. According to BZardi and Whiteman (2013) the mountain-plain wind system brings low level air into the mountain massif during daytime (the plain-to-mountain wind), with a weak return circulation aloft. During nighttime, the cir- culation reverses, bringing air out of the mountain mas- sif at lower levels (the mountain-to plain wind), with a weak return circulation aloft. The reversal of this large- scale wind system is somewhat delayed relative to the slope and valley wind systems because of its larger mass^. The strongest diurnal wind systems develop in dry, high-elevation climates because of the good expo- sure to solar radiation during the day and the strong long wave radiative loss during the night (Whiteman 2000). Deserts surrounded by high mountains and altitudes have a regular system of day and night winds that can affect the local wind structure in these areas. This study introduces a specific cyclone that appears in such deserts and plains. This cyclone begins to form in the morning with the sunrise and the rapid heating of the earth’ s surface by the sun, while the katabatic winds are still blowing and there is a positive vorticity in the desert. In the meantime, the mixed layer grows rapidly and the Bmorning cyclone^ forms which lasts until pre-noon, when the anabatic winds begin to blow and consequently there will be a negative vorticity. There are many deserts surrounded by mountains on the land surface. In this article, the morning cyclone is studied in two of these deserts including the Taklamakan, and Margo Desert. The Taklamakan Desert is one of the largest deserts and located farther from an ocean than any other desert in the world. It occupies the central part of the Tarim Basin in northwestern China, extending about 1000 km from east to west and 400 km from north to south (Fig. 1) with a dry continental climate (Huang et al. * Alireza Saeedi alirezasaeedi@ut.ac.ir 1 Department of Physical Geography, Faculty of Geography, University of Tehran, Azin Alley, Vesal Street, Engelab Ave, Tehran, Iran Theoretical and Applied Climatology https://doi.org/10.1007/s00704-018-2607-1