علوم غیرزیستی دریا
Maryam Soyuf Jahromi; Zohreh Shahmansoori
Abstract
In this study, sea level anomaly of Persian Gulf (spatial resolution of 0.25 degrees of latitudes and longitudes) was investigated in the MATLAB software environment by using long-term AVISO data for 25 years (1 January 1993 to 31 December 2017). The 25-year average of the data shows that the sea level ...
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In this study, sea level anomaly of Persian Gulf (spatial resolution of 0.25 degrees of latitudes and longitudes) was investigated in the MATLAB software environment by using long-term AVISO data for 25 years (1 January 1993 to 31 December 2017). The 25-year average of the data shows that the sea level anomaly is positive and equals 3.06 ± 0.05 cm (mean± standard deviation), which is higher than the global average. Its range varies from a minimum of 2.46 cm to a maximum of 3.42 cm. The 25-year average of each season illustrates that sea level anomalies face a rise in autumn and a fall in spring. The two seasons of summer and winter are transition seasons from the maximum anomaly of autumn to the minimum anomaly of spring. The results also show that the spatial distribution of sea level anomaly in the basin is different. The mean sea level anomaly trend in the Persian Gulf is +2.9±0.1 mm/year, which practically divides Persian Gulf in the three parts of northwestern parts near the Arabian coast (anomalies less than 2.5 mm/year), the northern and central parts of the gulf (anomalies of 2.5-5.5 mm/year) and the southern part of the gulf and Strait of Hormuz (anomalies more than 3.5 mm/year). Therefore, although the head of Persian Gulf has positive trend changes, it is less than its southern part and near the Strait of Hormuz. If the Persian Gulf Sea level continues to rise, over the next 200 years, the Persian Gulf sea level will rise more than 0.5 m, with significant changes in the size and area of the basin.
علوم غیرزیستی دریا
Atefe Pourkarimian; Maryam Soyuf Jahromi; Hossein Malakooti
Abstract
The new insights into ocean-atmosphere-land synoptic studies, have led scientists to trace attractive atmospheric and oceanic phenomena. In this study, by using synoptic maps and some precipitation indices for Iran, we estimated the type and intensity of the extreme precipitation event in Dayyer Port ...
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The new insights into ocean-atmosphere-land synoptic studies, have led scientists to trace attractive atmospheric and oceanic phenomena. In this study, by using synoptic maps and some precipitation indices for Iran, we estimated the type and intensity of the extreme precipitation event in Dayyer Port synoptical station (27˚51ʹ34ʺN-51˚57ʹ52ʺ, ID: 40872) for 19March 2017. In order to identify oceanic sources of the water content for this precipitation event, air parcels were traced as lagrangian single particle trajectory by a hybrid model of HYSPLIT which is run backward interactively on the web site, during 9-days by the start of maximum rainfall, locatacted at Dayyer port station. Accordingly, we plotted pattern of the average moisture transfer paths on 800-550 hPa atmospheric levels. The field climate data (including wind speed and direction, relative humidity and precipitation) with 6-hour time steps and spatial resolution of 2.5˚×2.5˚(longitude and latitude), entered into the model from the reanalysis global data archive of the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR). Consequently, by assessment of the meteorological maps and data and by using a precipitation index of R10mm, we found that this precipitation event (19th March 2017) defined as a heavy precipitation day. Finally, the simulation outputs clearly showed that the water contents of this rainfall system (19th March 2017) originates from two source locations of the north area of Indian Ocean (Arabian Sea), and also the east part of Atlantic Ocean. In addition, the results illustrated that during the occurrence of this precipitation event, an extra-tropical cyclone was active on the studied area.
علوم غیرزیستی دریا
Mahdieh Emami; Maryam Soyuf Jahromi; Alireza Behmanzadegan
Abstract
The coastline, as a border where the water flow is relatively impermeable, can change the flow pattern and therefore, the study of its hydrodynamic role is undeniable. in coastal engineering studies and even wet ecosystems even it is simple. In this study, using three-dimensional simulations in the numerical ...
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The coastline, as a border where the water flow is relatively impermeable, can change the flow pattern and therefore, the study of its hydrodynamic role is undeniable. in coastal engineering studies and even wet ecosystems even it is simple. In this study, using three-dimensional simulations in the numerical model environment of MIKE 3, the Danish Hydrodynamic Institute, two types of three dimensional simulations have been proposed using Navier Stokes equations to investigate the role of the coastline in rectangular and curved basins. In both simulations, it is assumed that the characteristics of Qeshm's tidal channel are scientifically established. This study clearly shows that the uniform velocity pattern in a rectangular basin changes with the curvature of coastline on the curved basin. The tightness in the curvature of the basin causes an increase in speed (about 0.05 m/s) in accordance with the principle of mass conservation. The opening after the turn of the basin causes a decrease of 0.1 m/s (0.4 m/s in the rectangular basin to 0.3 m/s in a curved basin, equivalent to 25% speed). Another point to consider is the role of water level changes. There is not much difference in the speed pattern between Higher High Water (HHW) and Lower Low Water (LLW) in Neap tide, but in the case of Spring tide where the water level is higher, the difference is 0.1 m/s in the rectangular basin and 0.2 m/s in the curved shape basin.