On the Investigation of the Typology of Fog Events in an Arid Environment and the Link with Climate Patterns

Abstract

<jats:title>Abstract</jats:title> <jats:p>The central aim of this work is to investigate the characteristics of fog events over the United Arab Emirates (UAE) and identify the underlying physical processes responsible for fog initiation and dissipation. To achieve this, hourly meteorological measurements at eight airport stations, along with ERA5 reanalysis data (1995–2018), are utilized. The analysis indicates the dominance of radiation fog (RAD) as, on average, 70% of the observed events fall under this category. Fog in the UAE typically forms between 2000 and 0200 local time (LT) and dissipates between 0600 and 0900 LT. During a typical dense fog event recorded during 22–23 December 2017, cooling and moistening tendencies of up to 1.2 K h−1 and 0.7 g kg−1 h−1 are observed ~5–6 h before fog onset. In the vertical, a dry and warm layer above 750 hPa gradually descends from above 500 hPa to promote the development of fog. Similar conclusions are reached when analyzing composites of fog events. Further, the variability of fog occurrence associated with El Niño–Southern Oscillation (ENSO) patterns is explored. It is concluded that the El Niño (warm) and La Niña (cold) phases exhibit very different spatial characteristics with respect to surface meteorological variables. In particular, during El Niño events, the near-surface atmosphere is cooler and moister compared to La Niña events, favoring RAD fog formation over the UAE. Besides, fog events during El Niño years tend to last longer compared to La Niña years due to an earlier onset.</jats:p>

Characteristics of Atmospheric Aerosols Over the UAE Inferred From CALIPSO and Sun Photometer Aerosol Optical Depth

“…As a result of the strong heating of the surface by the Sun, a thermal low develops in the region, known as the Arabian heat low (Schwitalla et al., 2020). In addition, the strong nighttime radiative cooling, especially in the cold months, can lead to the formation of fog (Chaouch et al., 2017; Gandhidasan & Abualhamayel, 2012; Mohan et al., 2020; Nelli et al., 2020a; Temimi et al., 2020; Weston et al., 2018), which is often a hazard for road and air traffic in the region (Aldababseh & Temimi, 2017). The atmosphere in the interior areas of the Arabian Peninsula is rather dry year‐round, which is favorable for the occurrence of dust storms (Nelli et al., 2020a; Yu et al., 2015), although strong evaporation over the Arabian Gulf and Sea of Oman can lead to specific humidities in excess of 20 g kg −1 locally (P. Xue & Eltahir, 2015), with this very moist air advected inland by the daytime sea‐breeze circulation.…”

Application of a Nighttime Fog Detection Method Using SEVIRI Over an Arid Environment

“…It has a mean spatial annual rainfall of about 78 mm/year [13], and the dominant land cover type is bare or sparsely vegetated desert. The UAE experiences radiation fog, most frequently in winter months [14,15]. Low visibility events are more often associated with humid atmospheric conditions than with dry and dusty conditions [16,17].…”

Ankara Esenboga International Airport (Turkey) fog analysis and synoptical investigation of the fog event dated 17–19 December 2019

“…Some of T A B L E 1 Flow chart showing the algorithm for classifying fog types (Source: Tardif and Rasmussen, 2007) the other studies carried out can be briefly listed as follows; Fog study was conducted on the plains of northern India using the Numerical Weather Prediction (NWP) model by Singh et al (2018). The aim of the study by Mohan et al (2020) The aim of the current study is to analyse the fog of Ankara Esenboga International Airport for the years 2011-2020, to analyse it statistically, to classify the fogs in the aviation instrument landing system (ILS) category, and to determine the CAT categories during foggy hours, to determine the fog types and to analyse the longest foggy day.…”

“…The aim of the study by Mohan et al . (2020) was to investigate the characteristics of fog events over the United Arab Emirates (UAE) and to determine the factors that cause the initiation/dissipation of fog. In a study by Marouane et al .…”