Seasonal variability of circulation and air-sea interaction in the Caspian Sea based on a high resolution circulation model

2019 ◽  
Vol 45 (6) ◽  
pp. 1113-1129
Author(s):  
F. Komijani ◽  
V. Chegini ◽  
S.M. Siadatmousavi
Keyword(s):  
High Resolution ◽  
Caspian Sea ◽  
Seasonal Variability ◽  
Circulation Model ◽  
The Caspian Sea

scholarly journals Long-Term Evolution of the Caspian Sea Thermohaline Properties Reconstructed in an Eddy-Resolving OGCM

2018 ◽  
Author(s):  
Gleb S. Dyakonov ◽  
Rashit A. Ibrayev
Keyword(s):  
Caspian Sea ◽  
General Circulation ◽  
Decadal Variability ◽  
Global Climate ◽  
Circulation Model ◽  
Ocean General Circulation Model ◽  
Atmospheric Conditions ◽  
The Caspian Sea ◽  
Error Accumulation

Abstract. The decadal variability of the Caspian Sea thermohaline properties is investigated by means of a high-resolution ocean general circulation model including sea ice thermodynamics and air-sea interaction, forced by prescribed realistic atmospheric conditions and riverine runoff. The model describes synoptic, seasonal and climatic variations of the sea thermohaline structure, water balance and level height. A reconstruction experiment was conducted for the period of 1961–2001, covering a major regime shift in the global climate of 1976–1978, which allows to investigate the Caspian Sea response to such significant episodes of climate change. The long-term trends in the sea circulation patterns are considered with an assessment of the influence of model error accumulation.

Detection of Destructive Zones of the Caspian Sea According to High-Resolution Seismic Data

2019 ◽  
Author(s):  
V.V. Dolgov ◽  
D.F. Ismagilov ◽  
A.V. Khortov ◽  
S.L. Maraev
Keyword(s):  
High Resolution ◽  
Seismic Data ◽  
Caspian Sea ◽  
The Caspian Sea

scholarly journals Interannual Variability of Water Exchange Anomalies Between the Northern, Middle and Southern Caspian Based on Satellite Altimetry Data

2019 ◽  
Vol 25 ◽  
pp. 106-115 ◽  
Author(s):  
Sergey A. Lebedev ◽  
Andrey G. Kostianoy
Keyword(s):  
Caspian Sea ◽  
Seasonal Variability ◽  
Satellite Altimetry ◽  
Water Exchange ◽  
Western Coast ◽  
Altimetry Data ◽  
The Caspian Sea ◽  
Volga River ◽  
Geostrophic Velocities ◽  
Satellite Altimetry Data

The paper presents the results of estimation of interannual and seasonal variability of water exchange between the Northern, Middle and Southern Caspian Sea based on the TOPEX/Poseidon and Jason–1/2/3 satellite altimetry data. The boundaries between the Caspian Sea sub-basins were taken along the 133 and 209 tracks of the satellites. Temporal variability of surface geostrophic velocities directed perpendicular to the tracks showed that positive values correspond to the southeast direction of the currents, negative values correspond to the northwest direction. It is clearly seen that the main water exchange associated with the Volga River runoff is concentrated along the western coast of the Caspian Sea. In this area, anomalies of geostrophic velocities exceed 20 cm/s. Total water exchange anomalies through the 133 and 209 tracks show seasonal variability with an amplitude up to ±18x105 m3/s for track 133 (a line between the Northern and Middle Caspian) and ±11x105 m3/s for track 209 (a line between the Middle and Southern Caspian). The maximum values of water exchange anomalies were observed in 1993, 1994 and 2012 through 133 track (±16-18x105 m3/s) and in 1993, 1996 and 1997 (±11x105 m3/s) through 209 track.

scholarly journals Storm surges and storm wind waves in the Caspian Sea in the present and future climate

2021 ◽  
Author(s):  
Anna Pavlova ◽  
Stanislav Myslenkov ◽  
Victor Arkhipkin ◽  
Galina Surkova
Keyword(s):  
Caspian Sea ◽  
Extreme Values ◽  
Wind Waves ◽  
Total Duration ◽  
Circulation Model ◽  
Storm Surges ◽  
Wave Model ◽  
The Caspian Sea ◽  
Storm Activity ◽  
Climatic Scenarios

Abstract. 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 of 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 the future was found, but it is not dramatically growing.

scholarly journals Comparing high-resolution gridded precipitation data with satellite rainfall estimates of TRMM_3B42 over Iran

2010 ◽  
Vol 25 ◽  
pp. 119-125 ◽  
Author(s):  
S. Javanmard ◽  
A. Yatagai ◽  
M. I. Nodzu ◽  
J. BodaghJamali ◽  
H. Kawamoto
Keyword(s):  
High Resolution ◽  
Caspian Sea ◽  
Annual Precipitation ◽  
Mean Annual Precipitation ◽  
Zagros Mountains ◽  
The Caspian Sea ◽  
Entire Country ◽  
The Mean ◽  
Satellite Rainfall ◽  
Rainfall Estimates

Abstract. To evaluate satellite rainfall estimates of Tropical Rain Measurement Mission (TRMM) level 3 output (3B42) (TRMM_3B42) over Iran (20°–45° N, 40°–65° E), we compared these data with high-resolution gridded precipitation datasets (0.25°×0.25° latitude/longitude) based on rain gauges (Iran Synoptic gauges Version 0902 (IS0902)). Spatial distribution of mean annual and mean seasonal rainfall in both IS0902 and TRMM_3B42 from 1998 to 2006 shows two main rainfall patterns along the Caspian Sea and over the Zagros Mountains. Scatter plots of annual average rainfall from IS0902 versus TRMM_3B42 for each 0.25°×0.25° grid cell over the entire country (25°–40° N, 45°–60° E), along the Caspian Sea (35°–40° N, 48°–56° E), and over the Zagros Mountains (28°–37° N, 46°–55° E) were derived. For the entire country, the Caspian Sea region, and the Zagros Mountains, TRMM_3B42 underestimates mean annual precipitation by 0.17, 0.39, and 0.15 mm day−1, respectively, and the mean annual rainfall spatial correlation coefficients are 0.77, 0.57, and 0.75, respectively. The mean annual precipitation temporal correlation coefficient for IS0902 and TRMM_3B42 is ~0.8 in the area along the Zagros Mountains, and ~0.6 in the Caspian Sea and desert regions.

scholarly journals A high resolution hydrodynamic 3-D model simulation of the malta shelf area

2003 ◽  
Vol 21 (1) ◽  
pp. 323-344 ◽  
Author(s):  
A. F. Drago ◽  
R. Sorgente ◽  
A. Ribotti
Keyword(s):  
High Resolution ◽  
Seasonal Variability ◽  
General Circulation ◽  
Large Scale ◽  
Current Knowledge ◽  
Model Simulation ◽  
Circulation Model ◽  
Surface Flow ◽  
Open Boundary ◽  
Shelf Area

Abstract. The seasonal variability of the water masses and transport in the Malta Channel and proximity of the Maltese Islands have been simulated by a high resolution (1.6 km horizontal grid on average, 15 vertical sigma layers) eddy resolving primitive equation shelf model (ROSARIO-I). The numerical simulation was run with climatological forcing and includes thermohaline dynamics with a turbulence scheme for the vertical mixing coefficients on the basis of the Princeton Ocean Model (POM). The model has been coupled by one-way nesting along three lateral boundaries (east, south and west) to an intermediate coarser resolution model (5 km) implemented over the Sicilian Channel area. The fields at the open boundaries and the atmospheric forcing at the air-sea interface were applied on a repeating "perpetual" year climatological cycle. The ability of the model to reproduce a realistic circulation of the Sicilian-Maltese shelf area has been demonstrated. The skill of the nesting procedure was tested by model-modelc omparisons showing that the major features of the coarse model flow field can be reproduced by the fine model with additional eddy space scale components. The numerical results included upwelling, mainly in summer and early autumn, along the southern coasts of Sicily and Malta; a strong eastward shelf surface flow along shore to Sicily, forming part of the Atlantic Ionian Stream, with a presence throughout the year and with significant seasonal modulation, and a westward winter intensified flow of LIW centered at a depth of around 280 m under the shelf break to the south of Malta. The seasonal variability in the thermohaline structure of the domain and the associated large-scale flow structures can be related to the current knowledge on the observed hydrography of the area. The level of mesoscale resolution achieved by the model allowed the spatial and temporal evolution of the changing flow patterns, triggered by internal dynamics, to be followed in detail. This modelling effort has initiated the treatment of the open boundary conditions problem in view of the future implementation of shelf-scale real-time ocean forecasting through the sequential nesting of a hierarchy of successively embedded model domains for the downscaling of the hydrodynamics from the coarse grid Ocean General Circulation Model of the whole Mediterranean Sea to finer grids in coastal areas. Key words. Oceanography: general (continental shelf processes; numerical modelling) Oceanography: physical (general circulation)

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