scholarly journals Global Assessments of the HY-2B Measurements and Cross-Calibrations with Jason-3

2020 ◽  
Vol 12 (15) ◽  
pp. 2470 ◽  
Author(s):  
Yongjun Jia ◽  
Jungang Yang ◽  
Mingsen Lin ◽  
Youguang Zhang ◽  
Chaofei Ma ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Sea Level ◽  
Surface Wind ◽  
Sea Surface ◽  
Radar Altimeter ◽  
Significant Wave ◽  
Comparison Results ◽  
Wave Heights ◽  
Significant Wave Heights

The HY-2B satellite was successfully launched on 25 October 2018. One of the main payloads of the HY-2B was a radar altimeter. In the present study, the quality of the HY-2B along-track sea surface heights (SSH), significant wave heights (SWH), and sea surface wind speeds (SSWS) were assessed, including their precision and accuracy. In order to achieve this goal, the mono-mission metrics of the HY-2B were analyzed and compared with those of the Jason-2 and Jason-3 over the same periods of time. The results of both direct comparison and cross comparison methods were presented in this study. The comparison results indicated that the quality of the HY-2B satellite’s geophysical data records (GDRs) data was excellent, with 95% of the sea surfaces effectively observed between 82 degrees north and south latitudes. In addition, the standard deviation of the sea level anomalies (SLA) at the single mission crossovers was 4.6 cm to 5.8 cm, and at the dual-crossovers with Jason-3, the standard deviation was determined to be 5.1 cm to 5.8 cm. The accuracy levels of the significant wave heights and products of the HY-2B satellite radar altimeter were observed to be greater than 0.3 m and 1.4 m/s (STD), respectively. Therefore, it was concluded in this study that the data quality and system performance of the HY-2B satellite were excellent and stable, and could be widely utilized in such fields as global sea-level change monitoring, wave numerical assimilation predictions etc.

scholarly journals Improving Altimeter Wind Speed Retrievals Using Ocean Wave Parameters

2020 ◽  
Author(s):  
Haoyu Jiang ◽  
Hao Zheng ◽  
Lin Mu
Keyword(s):  
Surface Wind ◽  
Sea Surface ◽  
Atmospheric Parameters ◽  
Sea Temperature ◽  
Wind Speeds ◽  
Sea Surface Wind ◽  
Wave Heights ◽  
Data Source ◽  
Significant Wave Heights ◽  
The Impact

Spaceborne altimeters are an important data source for obtaining global sea surface wind speeds (U10). Although many altimeter U10 algorithms have been proposed and they perform well, there is still room for improvement. In this study, the data from ten altimeters were collocated with buoys to investigate the error of the altimeter U10 retrievals. The U10 residuals were found to be significantly dependent on many oceanic and atmospheric parameters. Because these oceanic and atmospheric parameters are inter-correlated, an asymptotic strategy was used to isolate the impact of different parameters and establish a neural-network-based correction model of altimeter U10. The results indicated that significant wave heights and mean wave periods are effective in correcting U10 retrievals, probably due to the tilting modulation of long-waves on the sea surface. After the wave correction, the root-mean-square error of the retrieved U10 was reduced from 1.42 m/s to 1.24 m/s and the impacts of thermodynamic parameters, such as sea surface (air) temperate, became negligible. The U10 residuals after correction showed that the atmospheric instability can lead to errors on extrapolated buoy U10. The buoy measurements with large air-sea temperature differences need to be excluded in the Cal/Val of remotely sensed U10.

scholarly journals Estimating the Annual Exceedance Probability of Water Levels and Wave Heights from High Resolution Coupled Wave-Circulation Models in Long Island Sound

2020 ◽  
Vol 8 (7) ◽  
pp. 475
Author(s):  
Chang Liu ◽  
Yan Jia ◽  
Yaprak Onat ◽  
Alejandro Cifuentes-Lorenzen ◽  
Amin Ilia ◽  
...  
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Long Island ◽  
Long Island Sound ◽  
Water Levels ◽  
Eastern Coast ◽  
Significant Wave ◽  
Wave Heights ◽  
Significant Wave Heights ◽  
Island Sound

Accurately estimating the probability of storm surge occurrences is necessary for flood risk assessments. This research models Long Island Sound using a coupled coastal circulation and wave model (FVCOM-SWAVE) to hindcast the 44 highest storms between 1950–2018 and fitted Poisson-GPD distributions to modelled water levels and wave heights. Floodwater elevations and significant wave heights for 10% (1/10), 3% (1/30), 2% (1/50), and 1% (1/100) annual exceedance probabilities are provided for all Connecticut coastal towns. The results show that both water levels and their corresponding return intervals are higher along the western coast of Connecticut than the eastern coast, whereas significant wave heights increase eastward. Comparing our model results with those from the North Atlantic Coast Comprehensive Study (NACCS) shows that the mean NACCS results are higher for water levels and lower for significant wave heights for longer return periods. Likewise, the Federal Emergency Management Agency (FEMA) results in large errors compared to our results in both eastern and western coastal Connecticut regions. In addition to evaluating historical risks, we also added a sea-level height offset of 0.5 m for 2050 estimates in order to examine the effect of rising sea-levels on the analysis. We find that sea-level rise reduces the return period of a 10-year storm to two years. We advise periodically updating this work as improved sea-level rise projections become available.

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
Keyword(s):  
Surface Waves ◽  
Ocean Surface ◽  
Separation Distance ◽  
Ocean Surface Waves ◽  
Significant Wave ◽  
Storm Wave ◽  
Wave Heights ◽  
Significant Wave Heights ◽  
The One ◽  
Along Track

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.

scholarly journals HYDRODYNAMIC AND BOUSSINESQ WAVE MODELING FOR THE N219 AMPHIBIOUS AIRCRAFT SEAPLANE DOCK DEVELOPMENT PLAN IN PANJANG ISLAND

2021 ◽  
Vol 15 (2) ◽  
Author(s):  
Hanah Khoirunnisa ◽  
Mardi Wibowo ◽  
Wahyu Hendriyono ◽  
Khusnul Setia Wardani
Keyword(s):  
Flight Test ◽  
The Other ◽  
Waveform Modeling ◽  
Significant Wave ◽  
Other Hand ◽  
Wave Heights ◽  
Significant Wave Heights ◽  
Wave Conditions ◽  
The Difference ◽  
Mike 21

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.

Wave climate change in the Gulf of Bothnia

2021 ◽  
Author(s):  
Jan-Victor Björkqvist ◽  
Jani Särkkä ◽  
Hedi Kanarik ◽  
Laura Tuomi
Keyword(s):  
Climate Change ◽  
Wave Model ◽  
Wave Climate ◽  
Atmospheric Forcing ◽  
Simulation Data ◽  
Significant Wave ◽  
Gulf Of Bothnia ◽  
Wave Heights ◽  
Significant Wave Heights ◽  
Projected Changes

<p>Wave climate change in the Gulf of Bothnia in 2030–2059 was investigated using regional wave climate projections. For the simulations we used wave model WAM. As the atmospheric forcing for the wave model we had three global climate scenarios (HADGEM2-ES, MPI-ESM, EC-EARTH) downscaled with RCA4-NEMO regional model. The ice concentration for the wave model was obtained from NEMO ocean model simulations using the same atmospheric forcing. We used both RCP4.5 and RCP8.5 greenhouse gas scenarios. The spatial resolution of the simulation data was 1.8 km, enabling detailed analyses of the wave properties near the coast. From the simulation data we calculated statistics and return levels of significant wave heights using extreme value analysis, and assessed the projected changes in the wave climate in the Gulf of Bothnia. The projected increase in the significant wave heights is mainly due to the decreasing ice cover, especially in the Bothnian Bay. Projected changes in the most prevalent wind direction impacts the spatial pattern of the wave heights in the Bothnian Sea.</p>

Seasonal Variation of Surface Circulation Along Peninsular Malaysia' East Coast

2014 ◽  
Vol 71 (4) ◽  
Author(s):  
Muhammad Faiz Pa'suya ◽  
Kamaludin Mohd Omar ◽  
Benny N. Peter ◽  
Ami Hassan Md Din ◽  
Mohd Fadzil Mohd Akhir
Keyword(s):  
Sea Level ◽  
East Coast ◽  
Peninsular Malaysia ◽  
Environmental Data ◽  
Sea Surface ◽  
Northeast Monsoon ◽  
Radar Altimeter ◽  
Sea Level Anomaly ◽  
Surface Circulation ◽  
Altimetric Data

The sea surface circulation pattern over the coast of Peninsula Malaysia's East Coast during Northeast Monsoon (NE) and Southwest Monsoon (SW) are derived using the seasonally averaged sea level anomaly (SLA) data from altimetric data and 1992-2002 Mean Dynamic Ocean Topography. This altimetric data has been derived from multi-mission satellite altimeter TOPEX, ERS-1, ERS-2, JASON-1, and ENVISAT for the period of nineteen years (1993 to 2011) using the Radar Altimeter Database System (RADS). The estimated sea level anomaly (SLA) have shown similarity in the pattern of sea level variations observed by four tide gauges. Overall, the sea surface circulations during the NE and SW monsoons shows opposite patterns, northward and southward respectively. During the SW monsoon, an anti-cyclonic circulation has been detected around the Terengganu coastal area centred at (about 5.5° N 103.5° E) and nearly consistent with previous study using numerical modelling. The estimated geostrophic current field from the altimeter is consistent with the trajectories of Argos-tracked Drifting Buoys provided by the Marine Environmental Data Services (MEDS) in Canada.

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