Papers by Hossein Farjami
Journal of geophysical research. Atmospheres, Feb 12, 2024
Regional Studies in Marine Science
Fisheries Science and Technology, Jan 10, 2020
Journal of Oceanography, Jan 15, 2012
DOAJ (DOAJ: Directory of Open Access Journals), Jun 1, 2016
Remote Sensing Letters, Jun 28, 2016
ABSTRACT In this study, nadir altimeter radar measurements are used to improve wind speed and sea... more ABSTRACT In this study, nadir altimeter radar measurements are used to improve wind speed and sea state information in coastal regions, more precisely the north Indian Ocean. A methodology is suggested to combine the Ku- and C-band radar measurements, their difference, the measured significant wave height (HS) parameter and its along-track gradient. A dimensionless HS is used to recover empirical dependencies for fetch-limited wind wave development in this coastal region. As obtained, these simultaneous measurements can be efficiently combined to more precisely separate wind-related short-scale wave contributions from large-scale wave components, related to the local sea state degree of development. As demonstrated, this development helps to gain valuable insights concerning the use of altimeter measurements in coastal regions.
Regional Studies in Marine Science, Mar 1, 2020
Arabian Journal of Geosciences, Oct 1, 2021
Surface and subsurface eddies are presented in the Strait of Hormuz based on a synthetic data set... more Surface and subsurface eddies are presented in the Strait of Hormuz based on a synthetic data set including in situ hydrographic measurements, satellite altimetry, and reanalysis model results for summer 2013. The scale of Intrathermocline eddies (ITEs) were variable with a few 10 km in diameter and few 10 m in thickness. Also, our results indicate that the interaction between the Persian Gulf outflow dense water and Indian Ocean Surface Water inflow, as well as their interaction with the topography, might be the prime mechanism of forming ITEs in the region. The Persian Gulf dense water pushes ITEs upward. Turner angle suggests that the ITEs in the eastern part of the Strait of Hormuz are decaying or growing while the ITEs in the western part are rather stable.
اقیانوسشناسی, Mar 1, 2020
Remote Sensing Letters, Nov 17, 2020
Wind is a major factor which induces oceanic currents and many theories including the Ekman theor... more Wind is a major factor which induces oceanic currents and many theories including the Ekman theory have considered the wind induces currents. In this paper a numerical process has been used for forecasting of oceanic currents based on this theory. The survey has been done in an artificial five layer oceanic basin with smooth bottom of 120 meters, considering the geographic position of Persian Gulf. Primitive equations were solved on earth’s spherical coordinates system with sigma as vertical coordinate by finite element method. Vertical profile of predicted current vectors showed the complete formation of Ekman Spiral in the basin. This experimental simulation is a new approach for confirmation of Ekman Theory
Hydrophysics, Feb 19, 2021
Regional Studies in Marine Science, 2020
Abstract In this study, sea surface wind speed was investigated over the Caspian Sea. To do this,... more Abstract In this study, sea surface wind speed was investigated over the Caspian Sea. To do this, the accuracy of sea surface wind speed was evaluated using the Advanced Scatterometer (ASCAT) data, ERA-Interim and ERA5 reanalysis data based on the offshore platform measurements from 01 June 2014 until 09 July 2014. The analysis of data showed the ERA-Interim reanalysis data underestimated for winds greater than 6 m/s, while the ERA5 reanalysis data underestimated lower than 2 m/s. Also, the ASCAT wind speed data was found to have suitable agreements with in-situ measurements in the offshore of the south Caspian Sea. Then, the Empirical Orthogonal Functions (EOFs) analysis method was used to extract sea surface wind speed patterns over the study area using the ERA5 reanalysis data. Three main modes of EOFs respectively revealed 52, 17, and 10% of the total variance of sea surface wind speed over the Caspian Sea. The first mode of the EOFs indicated the most prevailing winds anomaly over the center and north of the region. The second EOFs pattern revealed storms and existence of a dipole system between southern and northern parts. Finally, the third EOFs pattern showed a small cyclone accounting for 10% of total variance over the northwest part of the Caspian Sea caused by the blocked cyclones from the Caucasus Mountains in the west and northwest of the study area.
Sea surface dynamics, especially wave characteristics and energy of waves are critically importan... more Sea surface dynamics, especially wave characteristics and energy of waves are critically important in ports and coastal designing, the operation of shipp ing and navigation, military science, fisheries, climate ch ange and etc.. In this study, the analyses combine a spatial variance and temporal variance modes are used to identify energy of wind waves patterns in the Arabia Sea. The method has practical applications in the EOF analysis of Altimeter data. For Arabian Sea the first mode 94.3 % of the spatial variance s hows pattern of energy of wind-driven waves and second mode is 2 .9% of the spatial variance. The eigenvector time series shows a seasonal modulation and potential of wind-driven waves energ y in the Arabian Sea.
Remote Sensing Letters, 2020
Identification and characteristics of Internal Waves (IWs) are widely used in a variety of indust... more Identification and characteristics of Internal Waves (IWs) are widely used in a variety of industries, including shipbuilding, maritime, as well as oil and marine engineering. In this study, IWs have been detected using field measurement and satellite remote sensing in the Persian Gulf during the period 2000–2015. In order to identify the potential areas for IWs after vertical changes in the physical parameters such as temperature, salinity, and sigma-T (σT) resulted by field measurements, the areas where high stratifications of seawater were identified. Satellite images corresponding to the identified areas were then prepared and the required modifications were made to the images. IWs were then manifested by such images in different parts of the study area. For the first time, a comprehensive map of the occurrence of IWs has been prepared and presented using Landsat 7 and 8, Sentinel-1 and Sentinel-2 images. Then, spatio-temporal analysis of IWs indicates that the density of them d...
Article History: Received: 3 May. 2016 Accepted: 15 Jun. 2016 To improve sea surface wind speed i... more Article History: Received: 3 May. 2016 Accepted: 15 Jun. 2016 To improve sea surface wind speed in coastal regions, we used nadir satellite altimeter measurements in the Persian Gulf and Arabian Sea. With combining normalized radar cross section for two bands of satellite altimeter measurements and significant wave height suggested the method to obtain “true” sea surface wind speed. In the coastal regions, we used a dimensionless significant wave height to gain empirical dependency to fetch-limited wind wave development. In this research, normalized radar cross section is simulated by using inverse wave age and fetch laws. As established this method helps to refine altimeter measurements of sea surface wind in the coastal regions.
Arabian Journal of Geosciences
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Papers by Hossein Farjami