Synoptic pattern of the Red Sea trough associated with spring dust over the northern and western Arabian Peninsula

Mashat, Abdulfattah S.; Awad, Adel; Assiri, Mazen E.; Labban, Abdulhaleem H.

doi:10.1007/s00703-020-00771-0

“…Characteristic contours of H are also widely adopted to define the boundary of a pressure system. For example, the H=5880 gpm contour at 500 hPa is widely used as the boundary of subtropical high pressure systems in the mid-troposphere, such as the western North Pacific subtropical high (WNPSH, e.g., Li et al 2021;Nie et al 2022;Yang et al 2023;Tang et al 2023;Zhang et al 2023) and the Iran high (e.g., Ninomiya and Kobayashi 1998;Rasul et al 2005;Mashat et al 2021;Zhang et al 2023), and the H=12500 gpm contour at 200 hPa is widely used as the boundary of the South Asian high (e.g., Sugimoto and Ueno 2012; Wei et al 2014;Choi et al 2015; Wang and Wang 2021;Cha et al 2021;Zhang et al 2023) in the upper troposphere.…”

Section: Introductionmentioning

confidence: 99%

Rising geopotential height under global warming

He,

Chen,

Collins

et al. 2024

Clim Dyn

4

0

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Geopotential height (H) is a widely used metric for atmospheric circulation. H has been reported to be rising under global warming, but the amplitude and mechanism of this rise are not clear. Based on reanalysis datasets and climate models participating in CMIP6, this study quantitatively evaluates the sensitivity of H to global mean surface air temperature (Ts), i.e., dH/dTs. Reanalysis datasets and model simulations consistently show that dH/dTs increases monotonically with altitude in the troposphere, with a global averaged value of about 24.5 gpm/K at 500 hPa, which overwhelms the interannual H variability. Diagnosis based on the hypsometric equation shows that the rise in H is dominated by temperature-driven expansion, i.e., expansion of the air column due to warming-induced reduction of air density, while moisture-driven expansion and the surface pressure effect play only minor roles. Therefore, the magnitude of dH/dTs is determined largely by a vertical integration of the warming profile below the pressure level. Since the anthropogenic forced rise in H is rather horizontally uniform and proportional to Ts change, past and projected future changes in the global H field at each pressure level can be reproduced by change in Ts multiplied by a constant historical dH/dTs value. The spatially uniform rise in H reproduces the past and projected future expansion of the widely used H=5880 gpm contour at 500 hPa, suggesting that it does not indicate enhancement of the subtropical high but is simply caused by thermal expansion of the atmosphere.

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“…Studies of the sources of dust in Southwest Asia have classified these sources into two main groups: local sources and remote sources (Notaro et al 2013). The local sources include the Rub Al Khali, the Ad Dahna, the An Nafud and the Syrian and Iraqi deserts, while the remote sources include the Sahara (Washington et al 2003;Osetinsky and Alpert 2006;Hannachi et al 2011;Awad and Mashat 2014;Yu et al 2013;Beegum et al 2018;Mashat et al 2021) (Figure 1-a). Specifically, among the local sources, the alluvial plain of the Tigris and Euphrates Rivers in Iraq is recognized as the main dust source in the Middle East region (Sissakian et al 2013;Zoljoodi et al 2013;Namdari et al 2018;Mohammadpour et al 2021).…”

Section: Introductionmentioning

confidence: 99%

“…Specifically, among the local sources, the alluvial plain of the Tigris and Euphrates Rivers in Iraq is recognized as the main dust source in the Middle East region (Sissakian et al 2013;Zoljoodi et al 2013;Namdari et al 2018;Mohammadpour et al 2021). Notaro et al (2013), using backward trajectories, identified the Rub Al Khali Desert as a major local dust source for western Saudi Arabia and the Sahara Desert as a major remote source (Mashat et al 2021). For northern and eastern Saudi Arabia, the Syrian and Iraqi Deserts were identified as the primary dust sources.…”

Section: Introductionmentioning

confidence: 99%

Synoptic characteristics of the spatial variability of spring dust storms over Saudi Arabia

Al-abbasi

¹

,

Labban²,

Awad³

2023

Atm.

Self Cite

1

0

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Statistical and synoptic studies of spring dust storms over the Arabian Peninsula (AP) were performed using surface observations from 27 surface stations and meteorological data from the NCEP/NCAR reanalysis data set for the period from 1978 to 2008. The study showed that, spatially, the northern and eastern AP are the most affected by dust storms and that, temporally, the study period can be divided into two subperiods before and after 1995, with a pronounced increase before 1995 and a smooth increase (decrease) after 1995 with respect to dust (dust storms) types. The synoptic study reveals three main atmospheric systems: frontal systems over the northern region, Red Sea Trough (RST)-related systems over the western region and thermal low systems over the eastern region. Additionally, the synoptic study shows that all of the atmospheric systems are associated with a favorable pressure (geopotential) gradient area and that the shape and strength of the maximum wind and upper-layer atmospheric regimes are suitable for completely integrating the atmospheric layers. Moreover, the southern thermal low is a common synoptic component of dust-related atmospheric systems, but its effect is particularly pronounced on the atmospheric system of the eastern region.

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“…Characteristic contours of H are also widely adopted to define the boundary of a pressure system. For example, the H=5880 gpm contour at 500 hPa is widely used as the boundary of subtropical high pressure systems in the mid-troposphere, such as the western North Pacific subtropical high (WNPSH, e.g., Li et al 2021;Nie et al 2022;Yang et al 2023;Tang et al 2023;Zhang et al 2023) and the Iran high (e.g., Ninomiya and Kobayashi 1998;Rasul et al 2005;Mashat et al 2021;Zhang et al 2023), and the H=12500 gpm contour at 200 hPa is widely used as the boundary of the South Asian high (e.g., Sugimoto and Ueno 2012; Wei et al 2014;Choi et al 2015; Wang and Wang 2021;Cha et al 2021;Zhang et al 2023) in the upper troposphere.…”

Section: Introductionmentioning

confidence: 99%

Rising geopotential height under global warming

He,

Chen,

Collins

et al. 2023

Preprint

0

View full text Add to dashboard Cite

Geopotential height (H) is a widely used metric for atmospheric circulation. H has been reported to be rising under global warming, but the amplitude and mechanism of this rise are not clear. Based on reanalysis datasets and climate models participating in CMIP6, this study quantitatively evaluates the sensitivity of H to global mean surface air temperature (Ts), i.e., dH/dTs. Reanalysis datasets and model simulations consistently show that dH/dTs increases monotonically with altitude in the troposphere, with a global averaged value of about 24.5 gpm/K at 500 hPa, which overwhelms the interannual H variability. Diagnosis based on the hypsometric equation shows that the rise in H is dominated by temperature-driven expansion, i.e., expansion of the air column due to warming-induced reduction of air density, while moisture-driven expansion and the surface pressure effect play only minor roles. Therefore, the magnitude of dH/dTs is determined largely by a vertical integration of the warming profile below the pressure level. Since the anthropogenic forced rise in H is rather horizontally uniform and proportional to Ts change, past and projected future changes in the global H field at each pressure level can be reproduced by change in Ts multiplied by a constant historical dH/dTs value. The spatially uniform rise in H reproduces the past and projected future expansion of the widely used H=5880 gpm contour at 500 hPa, suggesting that it does not indicate enhancement of the subtropical high but is simply caused by thermal expansion of the atmosphere.

show abstract

Synoptic pattern of the Red Sea trough associated with spring dust over the northern and western Arabian Peninsula

Cited by 6 publications

References 71 publications

Rising geopotential height under global warming

Rising geopotential height under global warming

Synoptic characteristics of the spatial variability of spring dust storms over Saudi Arabia

Rising geopotential height under global warming

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