scholarly journals Intraseasonal Sea-Level Variability in the Persian Gulf

Author(s):  
Christopher G. Piecuch ◽  
Ichiro Fukumori ◽  
Rui M. Ponte

AbstractSatellite observations are used to establish the dominant magnitudes, scales, and mechanisms of intraseasonal variability in ocean dynamic sea level () in the Persian Gulf over 2002–2015. Empirical orthogonal function (EOF) analysis applied to altimetry data reveals a basin-wide, single-signed intraseasonal fluctuation that contributes importantly to variance in the Persian Gulf at monthly to decadal timescales. An EOF analysis of Gravity Recovery and Climate Experiment (GRACE) observations over the same period returns a similar large-scale mode of intraseasonal variability, suggesting that the basin-wide intraseasonal variation has a predominantly barotropic nature. A linear barotropic theory is developed to interpret the data. The theory represents Persian-Gulf-average () in terms of local freshwater flux, barometric pressure, and wind stress forcing, as well as at the boundary in the Gulf of Oman. The theory is tested using a multiple linear regression with these freshwater flux, barometric pressure, wind stress, and boundary quantities as input, and as output. The regression explains 70%±79% (95% confidence interval) of the intraseasonal variance. Numerical values of regression coefficients computed empirically from the data are consistent with theoretical expectations from first principles. Results point to a substantial non-isostatic response to surface loading. The Gulf of Oman boundary condition shows lagged correlation with upstream along the Indian Subcontinent, Maritime Continent, and equatorial Indian Ocean, suggesting a large-scale Indian-Ocean influence on intraseasonal variation mediated by coastal and equatorial waves, and hinting at potential predictability. This study highlights the value of GRACE for understanding sea level in an understudied marginal sea.

2020 ◽  
Author(s):  
Christopher Piecuch ◽  
Rui Ponte ◽  
Ichiro Fukumori

<p>The Persian Gulf is a semi-enclosed marginal sea of the Indian Ocean. It connects to the Arabian Sea through the Gulf of Oman and the Strait of Hormuz. The Persian Gulf has a large coastal population, and is relevant economically and geopolitically, and so it is important to understand sea-level changes in the region. We use satellite observations from the Gravity Recovery and Climate Experiment (<strong>GRACE</strong>) and satellite altimetry to study intraseasonal sea level variation over the Persian Gulf during 2002-2015. We interrogate the spatial scales and forcing functions of the variation and its relation to large-scale circulation and climate over the Indian Ocean. Empirical orthogonal function analysis applied to sea level data from satellite altimetry reveals that the intraseasonal sea level variation in the Persian Gulf is dominated by a basin-wide, single-signed mode of fluctuation. Maximum covariance analysis applied to altimetry and GRACE satellite retrievals shows that these basin-wide intraseasonal sea level fluctuations are largely barotropic in nature and coupled to variations in ocean bottom pressure. To interpret the results, we develop a simple linear barotropic theory based on volume and momentum conservation. The theory describes Persian Gulf sea level in terms of freshwater flux over the region, wind stress along the Strait of Hormuz, and sea level in the Gulf of Oman. To test this theory, we perform a complex multiple linear regression using these regional freshwater flux, wind stress, and sea level as inputs, and Persian Gulf sea level as output. The regression model explains ~70% of the intraseasonal Persian Gulf sea level variance. The magnitudes and phases of the coefficients determined from the regression model are consistent with expectations from the simple theory. The Gulf of Oman sea level boundary condition shows significant lagged correlation with intraseasonal sea level upstream along the Indian Subcontinent, Maritime Continent, and equatorial Indian Ocean. This hints at a large-scale circulation and climate influence on intraseasonal sea level variation of the Persian Gulf mediated by waves propagating along equatorial and coastal waveguides. This study highlights the value of GRACE retrievals of ocean bottom pressure for understanding sea level in an understudied semi-enclosed marginal sea.</p>


Zootaxa ◽  
2020 ◽  
Vol 4852 (3) ◽  
pp. 333-349
Author(s):  
FARZANEH MOMTAZI

The representatives of the genus Ampelisca Krøyer, 1842 collected during the PGGOOS expedition (the Persian Gulf and Gulf of Oman Oceanographic Study) were studied. The species Ampelisca persicus sp. nov., Ampelisca lowryi sp. nov. and Ampelisca linearis sp. nov. were described. A redescription of Ampelisca cyclops Walker, 1904 was prepared based on material of the western part of the Indian Ocean. The differences between this and other records of A. cyclops were studied. 


Zootaxa ◽  
2019 ◽  
Vol 4711 (1) ◽  
pp. 77-106
Author(s):  
YASER FATEMI ◽  
SABINE STÖHR

Published records on the Ophiuroidea fauna of the Persian Gulf and Gulf of Oman are scattered in difficult to access journals and books. This study presents a compilation of all published records, complemented with data from new samples. Distribution, habitat and depth in the study area, as well as known Indian Ocean distributions, are included. The taxonomic status of all species was evaluated, critical comments were added as applicable, and several previous records were reassigned to other species. Ophiocoma erinaceus was removed from the fauna of the Persian Gulf and Gulf of Oman, because the only published record was instead Ophiocoma schoenleinii. Previous studies assumed that 46 species of brittle star were known from the study area, but only 38 species were confirmed by this re-assessment, including two new records (Ophiothrix (Ophiothrix) foveolata and Ophiocomella sexradia). Diagnostic features are supplied for difficult to distinguish species. Five species (Macrophiothrix elongata, Amphiura fasciata, Amphiura (Ophiopeltis) hexactis, Amphioplus echinulatus, and Amphioplus seminudus) are so far worldwide known only from the Persian Gulf area. A hexamerous, fissiparous species of Ophiothela that does not concur with any known species was found and may represent a new species. All newly collected species are illustrated with photographs. 


Zootaxa ◽  
2011 ◽  
Vol 2911 (1) ◽  
pp. 1 ◽  
Author(s):  
REZA NADERLOO ◽  
MICHAEL TÜRKAY ◽  
MICHAEL APEL

The family Macrophthalmidae Dana, 1851, is one of the best represented brachyuran groups in intertidal habitats in the Persian Gulf. Nine species from two subfamilies are reported from the gulf and the adjacent Gulf of Oman, mainly inhabiting intertidal soft substrates. The subfamily Ilyograpsinae Števcic, 2005, is represented by Ilyograpsus rhizophorae Barnard, 1950, erroneously recorded as I. paludicola (Rathbun, 1909). Eight species of the subfamily Macrophthalminae Dana, 1851, have been recorded from the area, all belonging to Macrophthalmus Desmarest, 1823. Of these, M. sinuspersici Naderloo & Türkay, 2010, has recently been described and is the only species of the genus occurring on rocky shores. Macrophthalmus graeffei A. Milne-Edwards, 1873, occurs in subtidal water and is hereby recorded for the first time from the northern Indian Ocean. The remaining six species, M. dentipes Lucas, 1836, M. depressus Rüppell, 1830, M. grandidieri A. Milne-Edwards, 1867, M. laevis A. Milne-Edwards, 1867, M. serenei Takeda & Komai, 1991, and M. sulcatus H. Milne-Edwards, 1852, are important elements of the intertidal soft bottom communities. An identification key for the genus Macrophthalmus in the area is provided, and the geographical distribution of the family is briefly discussed.


Author(s):  
Sara Karami

Introduction: The entry of dust particles into water areas, which has increased sharply in recent years, causes a lot of environmental damage. The Persian Gulf and the Gulf of Oman are among the water areas that are covered with dust many times of the year. Materials and methods: In this study, a severe dust from July 27 to 31, 2018 is analyzed, in which a large part of the Persian Gulf, Oman Sea and the western part of the Indian Ocean was involved. To study this phenomenon from different perspectives, satellite products, visibility from synoptic stations and synoptic maps were analyzed and the output of two numerical dust models of NASA-GEOS and DREAM8-MACC were examined. To qualitative and quantitative evaluate of the model outputs, the Aerosol Optical Depth (AOD) of TERRA/MODIS was used. Results: Satellite imagery shows that in this case study, parts of the Persian Gulf and the Sea of Oman were affected by dust, and on July 30, dust particles entered the western half of the Indian Ocean. Comparison of model outputs with satellite data resulted that both models underestimate the AOD values, especially over water, and do not show well the entrance of dust particles into the eastern part of the Persian Gulf, the Gulf of Oman and the western half of the Indian Ocean. Conclusion: Qualitative and quantitative comparison of AOD output of the two models with satellite data showed that the NASA-GEOS model had better performance and its output correlation with observational data was higher.    


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