scholarly journals Numerical Analysis of the Effect of Binary Typhoons on Ocean Surface Waves in Waters Surrounding Taiwan

2021 ◽  
Vol 8 ◽  
Author(s):  
Tzu-Yin Chang ◽  
Hongey Chen ◽  
Shih-Chun Hsiao ◽  
Han-Lun Wu ◽  
Wei-Bo Chen

The ocean surface waves during Super Typhoons Maria (2018), Lekima (2019), and Meranti (2016) were reproduced using hybrid typhoon winds and a fully coupled wave-tide-circulation modeling system (SCHISM-WWM-III). The hindcasted significant wave heights are in good agreement with the along-track significant wave heights measured by the altimeters aboard the SARAL (Satellite with ARgos and ALtiKa) and Jason-2 satellites. Two numerical experiments pairing Super Typhoons Maria (2018) and Meranti (2016) and Super Typhoons Lekima (2019) and Meranti (2016) were conducted to analyze the storm wave characteristics of binary and individual typhoons. Four points located near the tracks of the three super typhoons were selected to elucidate the effects of binary typhoons on ocean surface waves. The comparisons indicate that binary typhoons not only cause an increase in the significant wave height simulations at four selected pints but also result in increases in the one-dimensional wave energy and two-dimensional directional wave spectra. Our results also reveal that the effects of binary typhoons on ocean surface waves are more significant at the periphery of the typhoon than near the center of the typhoon. The interactions between waves generated by Super Typhoons Maria (2018) and Meranti (2016) or Super Typhoons Lekima (2019) and Meranti (2016) might be diminished by Taiwan Island even if the separation distance between two typhoons is <700 km.

1999 ◽  
Vol 37 (1) ◽  
pp. 150-162 ◽  
Author(s):  
P.W. Vachon ◽  
J.W.M. Campbell ◽  
A.L. Gray ◽  
F.W. Dobson

Author(s):  
Erin E. Hackett ◽  
Anne M. Fullerton ◽  
Craig F. Merrill ◽  
Thomas C. Fu

Techniques for extracting surface wave characteristics from radar backscatter have been investigated and improved over the last several decades. Much of this research has focused on the use of backscatter intensity from navigational radars for characterization of wave period and direction, and has clearly demonstrated accurate measurement of these wave characteristics. However, the precise determination of significant wave height has been more problematic due to the required application of a modulation transfer function. Furthermore, low sea states generally do not provide enough backscatter intensity for evaluation of wave characteristics, and thus, navigational radar measurements are restricted to relatively high sea states. More recently, techniques using Doppler velocities as a measurement of surface waves have been an area of increasing focus and development. An advantage of this approach is that no modulation transfer function is required, and only phase information is used from the backscattered radar signal. Recent research suggests that the relationship between Doppler velocities and wave height may be more consistent than that between radar backscatter intensity and wave height. In July 2010, surface waves were measured during an experiment at the Scripps Institution of Oceanography pier. Radar measurements were performed using a high-resolution pulse-Doppler instrumentation radar at low grazing angle (∼1 deg) with a pulse repetition frequency of 800 Hz and spatial resolutions of 10–30 cm. Radar data for X- and Ku-bands using both VV and HH polarizations were collected. Concurrent buoy measurements were also performed, along with the collection of wind speed and direction data. Measured seaways consisted of small significant wave heights (glassy conditions to <1 m), and contained combinations of wind sea and swell. Doppler processing of the radar data provided estimates of surface wave orbital velocity spectra in wavenumber and frequency domains. The velocity spectra were converted to sea surface elevation spectra. Using these spectra, peak periods were computed as well as RMS wave heights, thus providing approximate significant wave heights. The methods for extracting wave spectra, peak periods, and significant wave heights are discussed, and results are compared with buoy measurements. When sufficient capillary waves existed on the sea surface, the radar and buoy measured wave spectra were in agreement, and analysis indicates that the instrumentation radar was able to detect and spectrally distinguish between wind seas and swell.


2014 ◽  
Author(s):  
James M. Kaihatu ◽  
Alexandru Sheremet ◽  
Jame M. Smith ◽  
Hendrik L. Tolman

2021 ◽  
Vol 15 (2) ◽  
Author(s):  
Hanah Khoirunnisa ◽  
Mardi Wibowo ◽  
Wahyu Hendriyono ◽  
Khusnul Setia Wardani

The flight test of N219 Amphibious aircraft will be targeted in 2003/2024. For flight tests, these aircraft need a seaplane dock. One of the potential locations for the seaplane dock is Panjang Island at Seribu Islands. This study aims to know the characteristic of hydrodynamic and wave conditions and to determine whether Panjang Island is suitable for the seaplane dock. This study uses a modeling method with MIKE 21 FM HD-SW module and MIKE 21 Boussinesq Wave (BW)  module. The bathymetry data were obtained from the Indonesian Navy Hydrographic and Oceanographic Center (Pushidrosal), tide data is generated from Tide Model Driver (TMD), wave and wind data from ECMWF. The result of surface elevation validation between hydrodynamic modeling and TMD is 92%. During the west monsoon and spring conditions, the difference in the largest and lowest current velocity is quite large (0.018-0.199 m/s), on the other hand, when the tides are in neap conditions (0.008-0.144 m/s). Meanwhile, during the east monsoon and spring conditions, the difference in the largest and lowest current velocities is quite large (0.02-0.193 m/s), on the other hand, when the tides are in neap conditions (0.008-0.146 m/s). The maximum wave height resulting from the 50-year return period waveform modeling between 1.139 - 1.474 m. Meanwhile, the significant wave heights between 0.679 - 0.741 with a significant wave period of 13.45 seconds. In general, the current and wave conditions of the two locations are suitable for the construction of the seaplane dock, except that the dominant wave heights are still above the requirements.


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