Assessment of seasonal cloud properties in the United Arab Emirates and adjoining regions from geostationary satellite data

The present study mainly focuses on the United Arab Emirates (UAE) and adjoining areas, in the Arabian Peninsula, coming under the arid/semi-arid climatic conditions. The extremely intermittent rainfall strongly hinders the economic growth of this region. The freshwater primarily comes from the desalination of seawater along with other resources such as groundwater in the UAE region. Nevertheless, the declining groundwater reserves and expensive desalination approach have made to search for alternative sources for rain enhancement and one such approach is through the cloud seeding. However, there are barely few studies concentrated on the occurrence frequency of clouds and seasonal variability including their natural microphysics and dynamics that is crucial for precipitation augmentation through cloud seeding. Hence, the present study uses two geostationary satellites, namely, Meteosat-8 and Meteosat-10, due to their higher spatiotemporal observations in this region. The two geostationary satellites scan the UAE and adjoining regions in different view angles due to their positioning in different longitudes. Therefore, the Meteosat-8 has more advantage than Meteosat-10 in terms of the biases associated with the angular view and spatial resolution over the UAE and adjoining regions. Hence, the present study also evaluates the biases related to cloud occurrence due to different view angles. The winter (February March) and summer (June August) seasons indicate the frequent occurrence of clouds with distinct spatial distribution in these arid/semi-arid areas. The Arabian Gulf shows a higher percentage of clouds during winter while frequent convective clouds are noticed during summer over the Al Hajar Mountains. The evaluation of liquid and ice clouds also indicates that the warm cloud percentage is higher over the mountainous regions. However, the ice cloud distribution is higher over the Arabian Gulf during winter while they are highly confined along the Al Hajar Mountains in summer. The evaluation of cloud cover from Meteosat-10 and Meteosat-8 indicates the former shows higher occurrence percentage than the later. The significant biases are noted in warm cloud occurrence along the-mountainous regions from both the satellites. The fractional occurrence of rain is also estimated for different seasons based cloud liquid water path that provides key information to the seedable convective clouds. Therefore, the present study finds significant implications to the rain enhancement over arid and semi-arid regions in the Arabian Peninsula.