scholarly journals Cyclogenesis and Density Currents in the Middle East and the Associated Dust Activity in September 2015

Geosciences ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 376 ◽  
Author(s):  
Diana Francis ◽  
Noor Alshamsi ◽  
Juan Cuesta ◽  
Ayse Gokcen Isik ◽  
Cihan Dundar

The first 10 days of September 2015 were marked by intense dust activity over the Middle East and the Arabian Peninsula. This study examines the atmospheric conditions at the origin of the large dust storms during this period. We particularly investigate the atmospheric dynamics leading to the development of a large dry cyclone over Iraq on 31 August 2015 which in turn generated an intense dust storm that affected most of the countries around the Arabian Gulf and lasted for 5 days. We found that the cyclone developed over Northwest Iraq as a transfer to low levels of a cut-off low which had formed two days earlier at upper levels over Turkey. Large dust loads exceeding 250 tons were emitted and moved southeast in a cyclonic shape toward the Arabian sea. The second large dust storm on 6-8 September 2015 occurred over Syria and affected all the coastal countries on the eastern side of the Mediterranean Sea. It was associated with the occurrence of a series of density currents over northeast Syria emanating from deep convection over the mountainous border between Syria and Turkey. The unusual development of deep convection over this area was associated with a blocking high and interaction with orography. Both the cut-off high and the cut-off low occurred during a period characterized by a meandering polar jet and an enhanced subtropical jet causing unstable weather over mid-latitudes which in turn led to highly polluted atmosphere by natural dust in the affected countries.

2020 ◽  
Author(s):  
Diana Francis ◽  
Noor AlShamsi ◽  
Juan Cuesta ◽  
Ayse Gokcen Isik ◽  
Cihan Dundar

<p>The first 10 days of September 2015 were marked by an intense dust activity over the Middle East and the Arabian Peninsula. This study examines the atmospheric conditions at the origin of the large dust storms during this period. We particularly investigate the atmospheric dynamics leading to the development of a large dry cyclone over Iraq on 31 August 2015 which in turn generated an intense dust storm that affected most of the countries around the Arabian Gulf and lasted for 5 days. We found that the cyclone developed over Northwest Iraq as a transfer to low levels of a cut-off low which had formed two days earlier at upper levels over Turkey. Large dust loads exceeding 250 tons were emitted and moved southeast in a cyclonic shape toward the Arabian sea. The second large dust storm on 6-8 September 2015 occurred over Syria and affected all the coastal countries on the eastern side of the Mediterranean Sea. It was associated with the occurrence of a series of density currents over northeast Syria emanating from deep convection over the mountainous border between Syria and Turkey. The unusual development of deep convection over this area was associated with a blocking high and interaction with orography. Both the cut-off high and the cut-off low occurred during a period characterized by a meandering polar jet and an enhanced subtropical jet causing unstable weather over mid-latitudes which in turn led to highly polluted atmosphere by natural dust in the affected countries.<br>Keywords: Cut-off low; cut-off high; upper-level trough; density current; cyclone; evaporation cooling; desert areas; dust storms; polar jet; subtropical jet.</p>


2020 ◽  
Author(s):  
Bo Li ◽  
Jiang Zhang ◽  
Zongyu Yue ◽  
Peiwen Yao ◽  
Chenfan Li ◽  
...  

Abstract Dust storms, observed in all seasons, are among the most momentous Mars atmosphere activities. The Entry-Descent-Landing (EDL) activity of a Martian landing mission is influenced by local atmospheric conditions, especially the dust storm activity probability. It is of great significance to know well the dust storm situation that China's first Mars mission (Tianwen-1) may encounter in EDL season in the Chryse area, one of the tentative landing areas. Firstly, based on four Martian years’ Mars Orbiter Camera (MOC) Mars Daily Global Maps (MDGMs), 1172 dust storms were identified within Chryse’s 1600 km radius ring with their shape parameters extracted, including center, range and area. Secondly, the daily mean dust storm probability was calculated binned by 1° of solar longitude in the Chryse area during EDL season. Dust storm activity frequency was closely interrelated with the seasonal ebb and flow of the arctic polar ice cap, consequently, most of dust storms occurring in either the cap’s grow or the recession. The dust storm activity in the Chryse area mainly came from the northern polar cap region, Acidalia and Chryse, with some contribution from the southern hemisphere (Argyre and Bosprous) northward. Thirdly, we divided the Chryse area into many square grids of 0.5° and computed the average occurrence probability of dust storm in each grid during EDL season. The dust storm activity probability in space was also in-homogeneous, low in the west and south but high in the east and north, which was mainly affected by three factors: topography, the origin and the path of dust storm sequence. Based on Empirical orthogonal function (EOF) analysis, of the storms in the Chryse area we’ve discovered, 40.5% are cap-edge storms in the northern hemisphere and 17.5% are textured dust storms. Finally, according to the temporal and spatial probability of dust storm activity in the Chryse area during EDL season, we held that the preferred landing time of the Tianwen-1 mission in 2021 was in Ls=18°-65° and three preferred landing areas were selected with low dust storm probability.


2019 ◽  
Vol 76 (11) ◽  
pp. 3299-3326 ◽  
Author(s):  
Nicholas G. Heavens ◽  
David M. Kass ◽  
James H. Shirley ◽  
Sylvain Piqueux ◽  
Bruce A. Cantor

Abstract Deep convection, as used in meteorology, refers to the rapid ascent of air parcels in Earth’s troposphere driven by the buoyancy generated by phase change in water. Deep convection undergirds some of Earth’s most important and violent weather phenomena and is responsible for many aspects of the observed distribution of energy, momentum, and constituents (particularly water) in Earth’s atmosphere. Deep convection driven by buoyancy generated by the radiative heating of atmospheric dust may be similarly important in the atmosphere of Mars but lacks a systematic description. Here we propose a comprehensive framework for this phenomenon of dusty deep convection (DDC) that is supported by energetic calculations and observations of the vertical dust distribution and exemplary dusty deep convective structures within local, regional, and global dust storm activity. In this framework, DDC is distinct from a spectrum of weaker dusty convective activity because DDC originates from preexisting or concurrently forming mesoscale circulations that generate high surface dust fluxes, oppose large-scale horizontal advective–diffusive processes, and are thus able to maintain higher dust concentrations than typically simulated. DDC takes two distinctive forms. Mesoscale circulations that form near Mars’s highest volcanoes in dust storms of all scales can transport dust to the base of the upper atmosphere in as little as 2 h. In the second distinctive form, mesoscale circulations at low elevations within regional and global dust storm activity generate freely convecting streamers of dust that are sheared into the middle atmosphere over the diurnal cycle.


2017 ◽  
Vol 74 (4) ◽  
pp. 1011-1037 ◽  
Author(s):  
N. G. Heavens

Abstract Dust storms are Mars’s most notable meteorological phenomenon, but many aspects of their structure and dynamics remain mysterious. The cloud-top appearance of dust storms in visible imagery varies on a continuum between diffuse/hazy and textured. Textured storms contain cellular structure and/or banding, which is thought to indicate active lifting within the storm. Some textured dust storms may contain the deep convection that generates the detached dust layers observed high in Mars’s atmosphere. This study focuses on textured local dust storms in a limited area within Northeast (NE) Amazonis and Southwest (SW) Arcadia Planitiae (25°–40°N, 155°–165°W) using collocated observations by instruments on board the Mars Global Surveyor (MGS) and Mars Reconnaissance Orbiter (MRO) satellites. In northern fall and winter, this area frequently experiences dust storms with a previously unreported ruffled texture that resembles wide, mixed-layer rolls in Earth’s atmosphere, a resemblance that is supported by high-resolution active sounding and passive radiometry in both the near- and thermal infrared. These storms are mostly confined within the atmospheric boundary layer and are rarely sources of detached dust layers. The climatology and structure of these storms are thus consistent with an underlying driver of cold-air-advection events related to the passage of strong baroclinic waves. While the properties of the studied region may be ideal for detecting these structures and processes, the dynamics here are likely relevant to dust storm activity elsewhere on Mars.


2017 ◽  
Vol 17 (6) ◽  
pp. 4063-4079 ◽  
Author(s):  
Stavros Solomos ◽  
Albert Ansmann ◽  
Rodanthi-Elisavet Mamouri ◽  
Ioannis Binietoglou ◽  
Platon Patlakas ◽  
...  

Abstract. The extreme dust storm that affected the Middle East and the eastern Mediterranean in September 2015 resulted in record-breaking dust loads over Cyprus with aerosol optical depth exceeding 5.0 at 550 nm. We analyse this event using profiles from the European Aerosol Research Lidar Network (EARLINET) and the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO), geostationary observations from the Meteosat Second Generation (MSG) Spinning Enhanced Visible and Infrared Imager (SEVIRI), and high-resolution simulations from the Regional Atmospheric Modeling System (RAMS). The analysis of modelling and remote sensing data reveals the main mechanisms that resulted in the generation and persistence of the dust cloud over the Middle East and Cyprus. A combination of meteorological and surface processes is found, including (a) the development of a thermal low in the area of Syria that results in unstable atmospheric conditions and dust mobilization in this area, (b) the convective activity over northern Iraq that triggers the formation of westward-moving haboobs that merge with the previously elevated dust layer, and (c) the changes in land use due to war in the areas of northern Iraq and Syria that enhance dust erodibility.


Universe ◽  
2021 ◽  
Vol 7 (11) ◽  
pp. 433
Author(s):  
Bo Li ◽  
Zongyu Yue ◽  
Shaojie Qu ◽  
Peiwen Yao ◽  
Xiaohui Fu ◽  
...  

Dust storms, observed in all seasons, are among the most momentous of Mars’ atmospheric activities. The Entry–Descent–Landing (EDL) activity of a Martian landing mission is influenced by local atmospheric conditions, especially the probability of dust storm activity. Chryse Planitia, featuring many of the largest and most prominent outflow channels and possible mud volcanoes, is an important target site for current and future Mars landing missions. It is of great significance to understand that a Mars landing probe may encounter a dust storm situation during EDL season in the Chryse Planitia. In this study, based on four Martian years, Mars Orbiter Camera (MOC) Mars Daily Global Maps (MDGMs), 1172 dust storms were identified within Chryse’s 1600 km-radius ring. Secondly, the daily mean dust storm probability was calculated, binned by 1° of solar longitude in the Chryse landing area. The two active periods of dust storm activity are Ls = 177–239° and Ls = 288–4°, with an average daily mean dust storm probability of 9.5% and 4.1%. Dust storm activity frequency is closely interrelated with the seasonal ebb and flow of the north polar ice cap; consequently, most dust storms occur in either the cap’s growth or recession phase. We divided the Chryse landing area into square grids of 0.5° and computed the average probability of dust storm occurrence in each grid, which ranged from 0.19% to 2.42%, with an average of 1.22%. The dust storm activity probability in space was also inhomogeneous—low in the west and south but high in the east and north—which was mainly affected by the origin and the path of dust storm sequences. Based on empirical orthogonal function (EOF) analysis of storms in the Chryse area, 40.5% are cap-edge storms in the northern hemisphere. Finally, we concluded that the preferred time of a Mars landing mission is Ls = 18–65° in the Chryse Planitia, and three preferred landing areas were selected with low dust storm probability.


Author(s):  
A. Zandkarimi ◽  
P. Fatehi

Abstract. Dust storms are one of the common phenomena in the arid and semi-arid regions which cause many economic and environmental losses also affect human health. Therefore, it is necessary to be able to detect dust storms. Several methods exist for dust monitoring, such as Ground-based measurements, satellite remote sensing, video surveillance, wireless sensors. Remote sensing technology provides wide coverage, high spectral and temporal resolutions, even near real-time data, which can offer a valuable data source for dust storm monitoring. We used an algorithm based on Moderate Resolution Imaging Spectroradiometer (MODIS) images for detecting dust storm over the Middle East. The proposed algorithm uses the brightness temperature using multi-bands. The performance of the algorithm was evaluated using the ground-based observations of synoptic stations. The results showed that by applying the algorithm, the dust area can be clearly separated, especially in the regions that cloud is mixed with dust and achieved overall accuracy was ~78%.


Geosciences ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 453 ◽  
Author(s):  
Kaskaoutis ◽  
Francis ◽  
Rashki ◽  
Chaboureau ◽  
Dumka

The Sistan Basin has been recognized as one of the most active dust sources and windiest desert environments in the world. Although the dust activity in Sistan maximizes during the summer, rare but intense dust storms may also occur in the winter. This study aims to elucidate the atmospheric dynamics related to dust emission and transport, dust-plume characteristics, and impacts on aerosol properties and air quality during an intense dust storm over Sistan in February 2019. The dust storm was initiated by strong northerly winds (~20 ms−1) associated with the intrusion of a cold front from high latitudes. The upper-level potential vorticity (PV)-trough evolved into a cut-off low in the mid and upper troposphere and initiated unstable weather over Afghanistan and northern Pakistan. At the surface, density currents emanating from deep convective clouds and further strengthened by downslope winds from the mountains, caused massive soil erosion. The passage of the cold front reduced the temperature by ~10 °C and increased the atmospheric pressure by ~10 hPa, while the visibility was limited to less than 200 m. The rough topography played a major role in modulating the atmospheric dynamics, wind field, dust emissions, and transport pathways. Meso-NH model simulates large amounts of columnar mass dust loading (> 20 g m−2) over Sistan, while the intense dust plume was mainly traveling below 2 km and increased the particulate matter (PM10) concentrations up to 1800 µg m−3 at Zabol. The dust storm was initially moving in an arc-shaped pathway over the Sistan Basin and then it spread away. Plumes of dust covered a large area in southwest Asia, reaching the northern Arabian Sea, and the Thar desert one to two days later, while they strongly affected the aerosol properties at Karachi, Pakistan, by increasing the aerosol optical depth (AOD > 1.2) and the coarse-mode fraction at ~0.7.


2016 ◽  
Author(s):  
Stavros Solomos ◽  
Albert Ansmann ◽  
Rodanthi-Elisavet Mamouri ◽  
Ioannis Binietoglou ◽  
Platon Patlakas ◽  
...  

Abstract. The extreme dust storm that affected Middle East and the Eastern Mediterranean in September 2015 resulted in record-breaking dust loads over Cyprus with aerosol optical depth exceeding 5.0 at 550 nm. We analyze this event using profiles from the European Aerosol Research Lidar Network (EARLINET), the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO), geostationary observations from the Meteosat Second Generation – Spinning Enhanced Visible and Infrared Imager (MSG-SEVIRI) and high resolution simulations with the Regional Atmospheric Modeling System (RAMS). The analysis reveals the main mechanisms that resulted in the generation and persistence of the dust cloud over Middle-East and Cyprus. A combination of meteorological and surface processes is found: (a) the development of a thermal low at the area of Syria that results in unstable atmospheric conditions and dust mobilization at this area; (b) the convective activity over North Iraq that triggers the formation of a westward moving haboob that merges with the previously elevated dust layer; and (c) the changes in land use due to war at the areas of North Iraq and Syria that enhances dust erodibility.


2020 ◽  
Author(s):  
Bo Li ◽  
Peiwen Yao ◽  
Jiang Zhang ◽  
Zongyu Yue ◽  
Chenfan Li ◽  
...  

Abstract Dust storms, observed in all seasons, are among the most momentous Mars atmosphere activities. The Entry-Descent-Landing (EDL) activity of a Martian landing mission is influenced by local atmospheric conditions, especially the dust storm activity probability. It is of great significance to know well the dust storm situation that China's first Mars mission (Tianwen-1) may encounter in EDL season in the Chryse landing area, one of the tentative landing areas. Firstly, based on four Martian years’ Mars Orbiter Camera (MOC) Mars Daily Global Maps (MDGMs), 1172 dust storms were identified within Chryse’s 1600 km radius ring with their shape parameters extracted, including center, range and area. Secondly, the daily mean dust storm probability was calculated binned by 1° of solar longitude in the Chryse landing area during EDL season. Dust storm activity frequency was closely interrelated with the seasonal ebb and flow of the arctic polar ice cap, consequently, most of dust storms occurring in either the cap’s grow or the recession phase. The dust storm activity in the Chryse landing area mainly came from the northern polar cap region, Acidalia and Chryse, with some contribution from the southern hemisphere (Argyre and Bosporos) northward. Thirdly, we divided the Chryse landing area into many square grids of 0.5° and computed the average occurrence probability of dust storm in each grid during EDL season. The dust storm activity probability in space was also in-homogeneous, low in the west and south but high in the east and north, which was mainly affected by the origin and the path of dust storm sequence. Finally, according to the temporal and spatial probability of dust storm activity in the Chryse landing area during EDL season, we held that the preferred landing time of the Tianwen-1 mission in 2021 was in Ls=18°-65° and three preferred landing areas were selected with low dust storm probability.


Sign in / Sign up

Export Citation Format

Share Document