Haboob dust storms of the southern Arabian Peninsula

Abstract

The Arabic word “haboob,” meaning “strong wind,” describes a weather phenomenon characterized by immense walls of blowing sand and dust. Common to many parts of the Middle East, northern Africa, and the southwestern United States, haboobs are spawned by strong mesoscale downdrafts, making their prediction by coarse‐grid numerical models difficult in comparison to dust forced by synoptic‐scale dynamics. The United Arab Emirates Unified Aerosol Experiment (UAE2), an extensive field program conducted over the southeastern Arabian Peninsula during the summer of 2004, provided a unique opportunity to observe the haboob activity common to this region by way of a large assortment of satellite, radar, lidar, and meteorological station network observations. Here, we present results based on the UAE2 data set which add insight to the formation processes, multiscale structure, and transient behavior of haboobs as well as their potential importance to the regional aerosol burden. Satellite imagery and surface radar data assisted in the interpretation of highly dynamic storm evolution and outflow interactions. An idealized model of haboob dust production, parameterized by the strength and duration of the downburst, suggested that haboobs could be responsible for a nonnegligible component of the regional‐scale total dust production (up to 30% over a 1000 × 1000 km domain).

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

“…Haboobs occur mainly during spring and summer months when strong insolation combines with the influences of monsoonal moisture. At the synoptic scale, the westerly Shamal winds mobilize dust and sand, and transport it east and northeastward through the UAE, resulting in greater visibility impairment in summer [42]. Shamal winds are mostly strongest over the winter and summer seasons, so are the Shamal events (northwesterly winds blowing from the sea over the land) that are associated with low pressure, very high temperature, and relative humidity, which explains the low visibility observations during the summer.…”

“…This suggests that cities in the eastern part of the country encounter fewer poor visibility events than the remaining cities in the study area. The noticeable drop in visibility in summer is likely due to the presence of micro to mesoscale forcing mechanisms such as the Haboob wind (Arabic name of this wind) [42]. Haboobs occur mainly during spring and summer months when strong insolation combines with the influences of monsoonal moisture.…”

Observations of the temporal variability in aerosol properties and their relationships to meteorology in the summer monsoonal South China Sea/East Sea: the scale-dependent role of monsoonal flows, the Madden–Julian Oscillation, tropical cyclones, squall lines and cold pools

“…With the drop in temperature, there was a sharp spike in wind speed, relative humidity (and at times precipitation), as well as a drop in both particle concentration and water vapor mixing ratio. These characteristics are indicative cold pool events related to convective downdrafts (Wakimoto, 1985;Atkins and Wakimoto, 1991;Miller et al, 2008;Zuidema et al, 2012). Over 20 such events are observable in the time series, with significant variability in amplitude.…”

Dynamical mechanisms controlling the vertical redistribution of dust and the thermodynamic structure of the West Saharan atmospheric boundary layer during summer

“…Additionally, turbulence at the leading edge of cold pools is also efficient at lifting dust off the surface (F07). This dust is usually confined to the depth of the cold layer, but has been observed to precede it (Miller et al, 2008) or to mix into the SAL some distances behind the leading edge of the cold pool (F07; Bou Karam et al, 2008). Furthermore, in some instances, the dust lifted by a cold pool was observed to be transported isentropically up to the FT (F07).…”

“…They may also be triggered by convection over mountainous regions, such as the Atlas (Knippertz and Fink, 2006;Knippertz et al, 2007). Cold pool outflows may be moister or drier than their surroundings (Miller et al, 2008). As they propagate over the Sahara, they rapidly lift up and undercut SABL air masses, which may contain dust.…”