Spatial variability of summer hydrography in the central Arabian Gulf

The Arabian Gulf is a very significant ocean body, which hosts more than 55% of the oil reserves of the world and produces about 30% of the total production, and thus, it is likely to face high risk and adverse problems by the intensified environmental stressors and severe climatic changes. Therefore, understanding the hydrography of the Gulf is very essential to identify various marine environmental issues and subsequently, developing marine protection and management plans. In this study, hydrography data collected at 11 stations along 3 linear transects in the early summer of 2016 were analyzed. The physicochemical parameters exhibited apparent variations along each transect, both laterally and vertically, connected to stratification, formation of different water masses and excessive heating. The temperature and salinity decreased laterally from nearshore to offshore, while layered density structures were identified in the offshore regions. The pH, dissolved oxygen (DO) and chlorophyll fluorescence (Fo) exhibited distinct horizontal and vertical variations. The observed pH is within the normal ranges, indicating that seawater acidification may not be a threat. The highest DO (6.13–8.37 mg/l) was observed in a layer of 24-36 m water depth in the deeper regions of the central transect

Observed variability in physical and biogeochemical parameters in the central Arabian Gulf

In situ measurements of physical and biogeochemical variables were conducted along a transect in the Exclusive Economic Zone (EEZ) of Qatar during late summer (September 2014) and winter (January 2015) to investigate their vertical, spatial and temporal variability. The study reveals that the water column is characterized by strong stratification during late summer in the deepest station, where the water depth is around 65 m and the surface to bottom temperature variation is around 9.1°C. The water column is vertically homogeneous during winter due to surface cooling and wind mixing. The surface to 23 m water column is characterized by ample dissolved oxygen (DO) during late summer and winter in the offshore regions, however, relatively low DO is found during late summer due to weak mixing and advection under weak winds and currents. Dissolved oxygen drops to hypoxic levels below the summer thermocline, and the winter high DO layer extends up to the bottom. Chlorophyll-a (Chl-a) is relatively high during late summer in the offshore region, while that in the nearshore regions is very low, which is linked to the anthropogenic stresses from the central east coast of Qatar. The results identified in this study fill an essential gap in the knowledge of regional primary production dynamics.Environmental Science Center (ESC) & Department of Biological and Environmental Sciences (DBES), Qatar University (QU

Surface waves generated by shamal and easterly winds off Qatar

Waves in the Arabian Gulf are primarily controlled by the regional winds, for example, shamal winds during winter and early summer. Though Gulf wave characteristics have been heavily utilized for the design of offshore platforms and structures, wave features associated with various wind systems are not explicitly covered scientifically, say, for the Exclusive Economic Zone (EEZ) of Qatar. Therefore, we made an attempt to identify the features associated with different wind systems by analyzing the measured waves off Fuwairit, north coast of Qatar during 29 Oct - 26 Nov 2019. The analyses have been further extended to the Gulf using the reanalysis waves obtained from the COPERNICUS Marine Environment Monitoring Services (CMEMS) to describe the monthly, seasonal and annual characteristics. The results indicate that the easterly waves generated due to Nashi winds influence the east and northeast coasts of Qatar and shamal waves show clear dominance in the northern and northeastern offshore boundaries of the EEZ of Qatar. We find exceptional easterly (Nashi) waves during March 2019 contributing to the highest monthly mean significant wave height, which is a deviation from the known long-term wave climate of the Gulf

A multiscale ocean modelling system for the central Arabian/Persian Gulf: From regional to structure scale circulation patterns

The Arabian/Persian Gulf (hereafter, the “Gulf”) is one the busiest and fastest changing sea in the World. Its circulation is primarily driven by the surface water inflow from the Sea of Oman and density-driven and wind-driven flows within the Gulf. The regional circulation in its central part, particularly around Qatar, could not be explored because of unavailability of measured current data and the coarse resolution opted for the entire Gulf modelling. In the present study, we developed a high-resolution ocean modelling system of the entire Gulf with a particular focus on Qatar coastal waters. The model uses an unstructured mesh with different resolutions ranging from ∼5 km in the open ocean to ∼150 m along the coast of Qatar and less than 40 m around artificial structures. The model results have been validated with in situ data collected off Qatar. It allows seamless simulations of hydrodynamic processes from the entire basin scale down to the scale of coastal structures. The study identifies seasonal variability in currents and eddies in the central part of the Gulf. It also suggests the existence of four prominent anticyclonic eddies in the Gulf of Salwa, south of Bahrain. At the structure scale, the flow is mostly tidally driven and can be intensified beyond 1 m/s through narrow passages such as between breakwaters or within artificial waterways. By explicitly representing the effect of ocean sprawl on the coastal circulation, our model has the potential to greatly improve the environmental impact assessment of coastal developments in the Gulf area.We are grateful to Dr. Antoine Saint-Amand and Ms. Lauranne Alaerts for their help in producing some of the figures. We further thank Prof. Hamad Al-Saad Al-Kuwari, Director, Environmental Science Center (ESC), Qatar University (QU) for his constant encouragement and support. This work was jointly carried out by QU and UCLouvain under the QU Collaborative Grant project (QUCG-ESC-22/23-591), funded by QU, Qatar. Computational resources were provided by the Consortium des Équipements de Calcul Intensif (CÉCI), funded by the F.R.S.-FNRS, Belgium under Grant No. 2.5020.11

Wind energy potential along the onshore and offshore Qatar

Wind energy is one among the clean and renewable energy resources. The utilization of non-conventional energies over the conventional sources helps to reduce the carbon emissions significantly. The present study aims at investigating the wind energy potential at select coastal locations of Qatar using ERA5 winds. ERA5 is the updated reanalysis product of the European Centre for Medium-range Weather Forecasts (ECMWF), in which the scatterometer and in situ wind data are assimilated to improve the accuracy of predictions, thus the long-term and short-term variabilities are reasonably well captured. Compared to the earlier studies, in this work, we have assessed the wind power at inland and o?shore areas of Qatar, considering 40-year long (1979-2018) time series data with hourly ERA5 winds at 10-m height. The results show that there is no signi?cant increase or decrease of wind power around Qatar in the last 40 years in most of the locations, while there is a slight decreasing trend in the o?shore areas of Ruwais. This indicates that the average wind power is consistently available throughout the years. The links of climatic indices, especially the ENSO events with the wind climate of Qatar, are clearly evident in the long-term data. As obvious, the o?shore regions of Qatar have relatively high wind power compared to the land areas. Among the select locations, the highest annual mean wind power density is obtained in the o?shore Ruwais (152 W/m2), followed by o?shore Ras La?an (134 W/m2) and land area of Al Khor (120 W/m2). The maximum wind power density varies between 1830 and 2120 W/m2 in the land areas, while it is between 1850 and 2410 W/m2 in the o?shore areas of Qatar. The highest wind power is consistently available during the prevalence of shamal winds in winter (January-March) as well as summer (June)

Factors influencing the vertical distribution of microplastics in the beach sediments around the Ras Rakan Island, Qatar

Microplastic (MP) pollution is an emerging environmental problem, particularly in the marine environment, and nations are concerned about this issue. In this study, an attempt has been made to investigate the vertical distribution of MPs present in the beach sediments around the Ras Rakan Island of Qatar. Sampling was conducted at 9 locations, vertically to a depth of 30 cm with an interval of 5 cm. Attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy was used to chemically identify the subsets of MPs as polyethylene (PE), polypropylene (PP), polyamide (PA), polyethylene terephthalate (PET), polyvinyl chloride (PVC), and polystyrene (EPS). The counts of MPs were found to be higher in the western and northern parts of the island. The vertical distribution of MPs ranged from 0 to 665 particles/kilogram with maximum abundance at the surface layer (0-5 cm). Pellets were the dominant type of MPs in the surface sediments, whereas fibers were dominant in the bottom sediments. The prevailing winds, waves, tides, and currents are the forces responsible for the distribution and transport of MPs from offshore to the island and further to vertical re-distribution as time progresses. The level of MP pollution along the coast of Ras Rakan Island was higher than that found on the coast of mainland Qatar. Thus, informing that remote islands should also be considered for MP pollution monitoring programs to assess the risk associated with MP on the biota.This work has been carried out under the QU-NIO joint IRCC Project (No. IRCC-2019-002)

Climatology and variability of wind speeds along the southwest coast of India derived from Climate Forecast System Reanalysis winds

Wind climate along the southwest coast of India (Kerala coast) has been analysed using 41 years of Climate Forecast System Reanalysis (CFSR) winds to delineate long-term trends and variability. The study reveals significant decreasing trends in annual mean wind speeds, of the order of −2.0 to −2.5 cm·s−1·year−1, for the period 1979–2019. Southwest monsoon has contributed the highest weakening trends (−3.0 to −4.0 cm·s−1·year−1) due to significant decrease in the southwesterly/westerly wind speeds. The wind climate and trends during the northeast monsoon and premonsoon seasons have been characterized largely by the prevalence of sea breeze and shamal–makran wind systems. We find that the intensity of both sea breeze and shamal–makran wind systems reduces from north to south along the Kerala coast, which is in consistent with the earlier studies. Decadal oscillations in wind speeds, driven by the decadal variability in large-scale atmosphere–ocean circulations, are evident. Recent changes in the frequency of occurrence of Indian Ocean Dipole in the Indian Ocean have determined the overturning trends since 2010, and resulted in increasing trends in the current decade along the central and northern coasts of Kerala. Furthermore, interannual variability in wind speeds has been linked to the El Niño–Southern Oscillations (ENSO) and Indian Ocean Dipole (IOD)

Land reclamation and its consequences: A 40-year analysis of water residence time in Doha Bay, Qatar

Qatar's rapid industrialization, notably in its capital city Doha, has spurred a surge in land reclamation projects, leading to a constriction of the entrance to Doha Bay. By reducing and deflecting the ocean circulation, land reclamation projects have reduced the effective dispersion of wastewater introduced into the bay and hence degraded the water quality. Here, we assess fluctuations in water residence time across three distinct eras (1980, 2000, and 2020) to gauge the impact of successive land reclamation developments. To do this, we couple the multi-scale ocean model SLIM with a Lagrangian model for water residence time within Doha's coastal area. We consider three different topographies of Doha's shoreline to identify which artificial structures contributed the most to increase water residence time. Our findings reveal that the residual ocean circulation in Doha Bay was predominantly impacted by northern developments post-2000. Between 1980 and 2000, the bay's residence time saw a modest rise, of about one day on average. However, this was followed by a substantial surge, of three to six days on average, between 2000 and 2020, which is mostly attributable to The Pearl mega artificial island development. Certain regions of the bay witnessed a tripling of water residence time. Given the ongoing population expansion along the coast, it is anticipated that the growth of artificial structures and coastal reclamation will persist, thereby exacerbating the accumulation of pollutants in the bay. Our findings suggest that artificial offshore structures can exert far-reaching, non-local impacts on water quality, which need to be properly assessed during the planning stages of such developments

Land reclamation and its consequences: A 40-year analysis of water residence time in Doha Bay, Qatar: Data sets

<p>Meshes, polygons and winter/summer residence time outputs generated for Lecart et al (2024)</p&gt

La poldérisation et ses conséquences : Une analyse sur 40 ans du temps de résidence de l'eau dans la baie de Doha, au Qatar.

peer reviewedQatar's rapid industrialization, notably in its capital city Doha, has spurred a surge in land reclamation projects, leading to a constriction of the entrance to Doha Bay. By reducing and deflecting the ocean circulation, land reclamation projects have reduced the effective dispersion of wastewater introduced into the bay and hence degraded the water quality. Here, we assess fluctuations in water residence time across three distinct eras (1980, 2000, and 2020) to gauge the impact of successive land reclamation developments. To do this, we couple the multi-scale ocean model SLIM with a Lagrangian model for water residence time within Doha's coastal area. We consider three different topographies of Doha's shoreline to identify which artificial structures contributed the most to increase water residence time. Our findings reveal that the residual ocean circulation in Doha Bay was predominantly impacted by northern developments post-2000. Between 1980 and 2000, the bay's residence time saw a modest rise, of about one day on average. However, this was followed by a substantial surge, of three to six days on average, between 2000 and 2020, which is mostly attributable to The Pearl mega artificial island development. Certain regions of the bay witnessed a tripling of water residence time. Given the ongoing population expansion along the coast, it is anticipated that the growth of artificial structures and coastal reclamation will persist, thereby exacerbating the accumulation of pollutants in the bay. Our findings suggest that artificial offshore structures can exert far-reaching, non-local impacts on water quality, which need to be properly assessed during the planning stages of such developments