Investigation of Atmospheric Conditions Associated with a Storm Surge in the South-West of Iran (original) (raw)
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Storm surges and storm wind waves in the Caspian Sea in the present and future climate
This study is devoted to the analysis of the storm surges and wind waves in the Caspian Sea for the period from 1979 to 2017-2020. The models used are the circulation model ADCIRC and the wave model WAVEWATCH III with wind and pressure forcing from the NCEP/CFSR reanalysis. The modeling is performed on the unstructured grid with spacing to 300-700 m in the coastal zone. Mean and extreme values of surges, wave parameters, and storm activity are provided. The maximum significant wave height for the whole period amounts to 8.2 m. The average long-term SWH does not exceed 1.1 m. No significant trend in the storm activity was found. The maximum surges height amounts to 2.7 m. Analysis of the interannual variability of the surges occurrence showed that 7-10 surges with a height of more than 1 meter were obtained per year and the total duration all these surges was 20-30 days per year. Assessment of the risk of coastal flooding was carried out by calculating the extreme values of the Sea for different return periods 5, 10, 25, 50, and 100 years. The extreme sea level values in the northern part of the Caspian Sea for the return period 100 years is close to 3 m and the areas with big surges are located along the eastern and western coasts. Based on climatic scenarios of CMIP5, a forecast is made for the recurrence of storm wind waves in the 21st century. A statistically significant increase of storm waves recurrence in future was found, but it is not dramatically growing.
Storm Surges and Extreme Wind Waves in the Caspian Sea in the Present and Future Climate
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The Caspian Sea is of particular interest. Against the background of long-term sea level changes, low-lying coastal areas in the northern part are subject to constant flooding as a result of storm surges. The elongation of the sea in the meridional direction allows the development of strong waves in the middle and southern parts. A comprehensive understanding of the characteristics of storm surges and storm waves is especially important in the context of ongoing climate change. This study is devoted to the analysis of storm surges for the time period from 1979 up to 2017 and wind waves from 1979 to 2020 in the Caspian Sea region. The circulation model ADCIRC and the wave model WAVEWATCH III with wind and pressure forcing from the NCEP/CFSR reanalysis were used. The modeling is performed on different unstructured grids with spacings of 500–900 m in the coastal zone. Mean and extreme values of surges, wave parameters and storm activity are provided in the research. The maximum signifi...
Storm surge modeling in the Caspian Sea using an unstructured grid
Russian Journal of Earth Sciences, 2019
Investigation surges is important for studying patterns of water dynamics in the Northern Caspian. Modeling of wind-surges fluctuations in the Caspian Sea was performed using the model ADCIRC (ADvanced CIRCulation). For numerical experiments was constructed an irregular triangulation computational grid that consists of 71,523 elements with minimum cell size 500 m (off the coast) and maximum-10 km (in the center of the sea). It was compiled relative to the absolute zero water level for the Caspian Sea equal to −28 m BS (Baltic System), taking into account flooding and drying of the coastal land. The NCEP/CFSR reanalysis of surface wind at a height of 10 meters and the atmospheric pressure from 1979 to 2017 were used as the input data. Since the Northern Caspian is covered with ice in winter, the sea ice concentration of OSI-450 reprocessing were used. To assess the quality of the model, the obtained model level data were compared with level measurement on weather stations Tuleniy Island and Makhachkala from 2003 to 2017. The correlation coefficient for Tuleniy Island varied within 0.79-0.88, for Makhachkala-0.67-0.79. The mean value of the root-mean-square error was about 0.11 m for Tuleniy, and 0.06 m for Makhachkala. If we exclude fluctuations in sea level with an amplitude of less than 10 cm, the correlation values increase on average by 0.04. Three main synoptic situations were identified that lead to the formation of surges of more than 1 meter on Tuleniy Island. The contribution of wind to the formation of surge height is predominant (92-100%) compared with the contribution of the horizontal pressure gradient (0-8%).
Journal of Climatology & Weather Forecasting, 2014
The structure of five flood-producing storms was analyzed in northwestern Iran. The storms contained several coexisting convective cells during analysis period. We tried to obtain knowledge of Intensity, Duration and Type (IDT) of the storms by radar images and verify some convection-related parameters such as K, Showalter, Total-Total, Helicity and Energy-Helicity (EHI) indices; Convective available potential energy (CAPE) and Bulk Richardson number (BRN) in the area. The surface and upper air data were taken from General Forecast System (GFS) with spatial resolution of 0.5°×0.5° and a temporal resolution of 6 h. Results show, the CAPE values for thunderstorms are equal zero or less than 1000 Jkg-1 even for super and multi cells in the area. The most flood producing thunderstorms was single or multi cell and those merges together and makes Complex cell. One of the cases was twin squall lines that accompanied with cold front. Super-cell without Tornado sign was very infrequent. The growth of vertical cell in radar images has the direct relationships with convective available potential energy.
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Perspectives on Atmospheric Sciences, 2017
The storm surge, i.e. sea-level elevation due to severe atmospheric conditions (strong winds and low pressures), is a major factor of coastal inundation that can induce significant problems over low-land areas. 'WaveForUs' is a high-resolution forecasting system for public and emergency use that delivers meteorological and sea-state predictions over the Mediterranean Sea (0.15 o). The results of a 2-D hydrodynamic model, that simulates the sea-surface elevation due to the combined effect of atmospheric forcing (pressure and wind) and astronomical tides, are used to estimate the total surge along the coasts. The meteorological model used is the Weather Research and Forecasting model with the Advanced Research dynamic solver. We investigate the relation between extreme surge events and the atmospheric low-pressure systems during two severe weather events that appeared in the 2013-2015 period. Comparisons with the available satellite and in situ observations and gridded analyses show the good performance of the operational system. The morphological changes over a coastal region (e.g. orientation, existence of straits and islands) play an important role on the storm surge variability during a severe atmospheric low-pressure event. The seasonal variation of both weather storms and storm surges during the study period is also under investigation.
International Journal of Maritime …, 2008
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Storm Surge is an abnormal rise of water generated by a storm, over and above the predicted astronomical tides. Storm Surge should not be confused with storm tide, which is defined as the water level rise due to the combination of Storm Surge and the astronomical tide. This is a coastal flood or tsunami-like phenomena of rising water commonly associated with low pressure weather systems such as tropical cyclones Storm Surge is often the greatest threat to life and property from a hurricane. Storm Surge is one of the main causes of coastal inundation .Some mathematical models used to predict surge must incorporate the effects of winds, atmospheric pressure, tides, waves and river flows, as well as the geometry and topography of the coastal ocean and the adjacent flood plain. I have conducted many studies on the forecasting methods of Storm Surges and invented the Global Monsoon Time Scale, Astro-climatic weather forecasting study Time Scales, Bio-forecast effect along with the G.R.Irlapati's Geo-scope which may also useful in predicting the Storm Surges At The Time Of Tsunamis.