Analysis of the Long-Term Variability of Poor Visibility Events in the UAE and the Link with Climate Dynamics

Abstract

Abstract:The goal of this study is to investigate the variability of poor visibility events occurring hourly in the UAE and their relationship to climate dynamics. Hourly visibility observation data spanning more than three decades from ten stations across the country were used. Four intervals of low visibility, between 0.10 km and 5.0 km, were considered. Poor visibility records were analyzed under wet and dry weather conditions. The Mann-Kendall test was used to assess the inferred trends of low visibility records. The relationships between poor visibility measurements and associated meteorological variables and climate oscillations were also investigated. Results show that Fujairah city has the highest average visibility values under wet weather conditions, while Abu Dhabi city has the lowest average visibility values under both wet and dry conditions. Wet weather conditions had a greater impact than dry weather conditions on visibility deterioration in seven out of the ten stations. Results confirm that fog and dust contribute significantly to the deterioration of visibility in the UAE and that Abu Dhabi has been more impacted by those events than Dubai. Furthermore, the numbers of fog and dust events show steep increasing trends for both cities. A change point in poor visibility records triggered by fog and dust events was detected around the year 1999 at Abu Dhabi and Dubai stations after the application of the cumulative sum method. Increasing shifts in the means and the variances were noticed in the total annual fog events when Student's t-test and Levene's test were applied. In Abu Dhabi, the mean annual number of dust events was approximately 112.5 before 1999, increasing to 337 dust events after 1999. In Dubai, the number of dust events increased from around 85.5 to 315.6 events. The inferred fog and dust trends were compared to four climate indices. Results showed a significant correlation (positive and negative) between four climate indices and the occurrence of fog and dust events in the UAE.

Sensitivity study of the planetary boundary layer and microphysical schemes to the initialization of convection over the Arabian Peninsula

“…Figure shows the model probability for cloud development at three different time steps (left column) and the corresponding CM–SAF CWP observations (right column). At 0700 UTC, none of the models simulates any clouds over the UAE, while the observation shows haze or low stratus clouds near the east coast of the UAE, which is a common feature during wet conditions (Aldababseh and Temimi, ). At 0900 UTC, the models show a high probability for clouds over the Al Hajar mountains, which is well in accordance with the observations.…”

Analysis of a severe dust storm and its impact on air quality conditions using WRF-Chem modeling, satellite imagery, and ground observations

“…Despite low precipitation, fog is frequent especially during the months of November, December, and January. Fog results from strong temperature inversion in the desert which causes dew formation at the soil surface at night and early morning (Aldababseh and Temimi 2017;Chaouch et al 2017;Weston et al 2018) and may suppress dust emission temporarily (NCM 2011). When fog burns off just after sunrise, soil moisture decreases rapidly restoring soil erodibility.…”

A New Stochastic Model for the Boundary Layer Clouds and Stratocumulus Phase Transition Regimes: Open Cells, Closed Cells, and Convective Rolls

“…The induced reduced visibility, for example, has a great impact on the economies of many countries (Gultepe et al, 2007;Koraçin et al, 2014). Industries ranging from oil and gas explorations in northern communities of Atlantic Canada (Bullock et al, 2016) to airline transportation in Dubai (Aldababseh & Temimi, 2017) can be greatly affected by this problem. Despite extensive research devoted to the subject for centuries, determining the physical conditions under which fog develops has proven to be difficult (Gultepe et al, 2007).…”