scholarly journals Multi-phase seismic source imprint of tropical cyclones

2021 ◽  
Author(s):  
Lise Retailleau ◽  
Lucia Gualtieri
Keyword(s):  
Tropical Cyclones ◽  
Seismic Source ◽  
Wave Model ◽  
Site Effect ◽  
Ocean Waves ◽  
Body Waves ◽  
Seismic Arrays ◽  
Ocean Wave Model ◽  
Generation Mechanisms ◽  
Multi Phase

<p>The coupling between the ocean activity driven by winds and the solid Earth generates seismic signals recorded by seismometers worldwide. The 2-10 s period band, known as secondary microseism, represents the largest background seismic wavefield. While moving over the ocean, tropical cyclones generate particularly strong and localized sources of secondary microseisms that are detected remotely by seismic arrays.</p><p>We assess and compare the seismic sources of P, SV, and SH waves associated with typhoon Ioke during its extra-tropical transition. To understand their generation mechanisms, we compare the observed multi-phase sources with theoretical sources computed with a numerical ocean wave model, and we assess the influence of the ocean resonance (or ocean site effect) and coastal reflection of ocean waves. We show how the location and lateral extent of the associated seismic source is period- and phase-dependent. This information is crucial for the use of body waves for ambient noise imaging and gives insights about the sea state, complementary to satellite data.</p>

scholarly journals Multi-phase seismic source imprint of tropical cyclones

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Lise Retailleau ◽  
Lucia Gualtieri
Keyword(s):  
Tropical Cyclones ◽  
Seismic Source ◽  
Wave Model ◽  
Site Effect ◽  
Ocean Waves ◽  
Body Waves ◽  
Seismic Arrays ◽  
Ocean Wave Model ◽  
Generation Mechanisms ◽  
Multi Phase

AbstractThe coupling between the ocean activity driven by winds and the solid Earth generates seismic signals recorded by seismometers worldwide. The 2–10 s period band, known as secondary microseism, represents the largest background seismic wavefield. While moving over the ocean, tropical cyclones generate particularly strong and localized sources of secondary microseisms that are detected remotely by seismic arrays. We assess and compare the seismic sources of P, SV, and SH waves associated with typhoon Ioke (2006) during its extra-tropical transition. To understand their generation mechanisms, we compare the observed multi-phase sources with theoretical sources computed with a numerical ocean wave model, and we assess the influence of the ocean resonance (or ocean site effect) and coastal reflection of ocean waves. We show how the location and lateral extent of the associated seismic source is period- and phase-dependent. This information is crucial for the use of body waves for ambient noise imaging and gives insights about the sea state, complementary to satellite data.

Seasonal fluctuations in the secondary microseism wavefield recorded offshore Ireland

2020 ◽  
Author(s):  
Florian Le Pape ◽  
Christopher J. Bean
Keyword(s):  
Wave Model ◽  
Ocean Waves ◽  
Ocean Wave ◽  
Ocean Bottom ◽  
Ocean Bottom Seismometer ◽  
Storm Activity ◽  
Directional Spectrum ◽  
Sea Bottom ◽  
Ocean Wave Model ◽  
Obs Data

<p><span>Generated in the ocean, secondary microseisms result from the interaction of opposing ocean wave fronts and represent the strongest ambient seismic noise level measured on land. The recorded noise energy will vary with seasons due to changes in storm activity and associated secondary microseism source locations. Here, ocean bottom seismometer (OBS) data collected offshore Ireland in 2016 have been processed to look into the seasonal variations of the ambient noise wavefield recorded at the seafloor. Daily cross-correlations of OBS pairs located on top of thick sediments in deep water highlight seasonal changes between Rayleigh waves fundamental mode and first overtone for winter and summer months. Comparisons with ocean wave directional spectrum data derived from ocean wave model hindcasts suggest those variations are correlated with changing patterns in ocean waves interactions and therefore microseism source locations. In order to understand those observations in detail, we use 3D numerical simulations to show how the water column but also the subsurface structure below the sea bottom will affect the recorded wavefield at the seafloor for different stations and sources locations. Compared to land stations, the secondary microseism wavefield observed in the ocean and in particular changes in the excitation of Rayleigh modes due to site effects can help characterize the microseism source locations that fluctuate through the seasons.</span></p>

scholarly journals The Theory of Trapped-Fetch Waves with Tropical Cyclones—An Operational Perspective

2005 ◽  
Vol 20 (3) ◽  
pp. 229-244 ◽  
Author(s):  
Peter J. Bowyer ◽  
Allan W. MacAfee
Keyword(s):  
Tropical Cyclones ◽  
Wave Model ◽  
Ocean Waves ◽  
Resonance Phenomenon ◽  
High Wave ◽  
Almost All ◽  
High Degree ◽  
The Waves ◽  
Real Time Application ◽  
Operational Assessment

Abstract The majority of high wave events and almost all cases of extreme or phenomenal wave growth are the result of a high degree of synchronicity between moving storms and the waves that they generate. This wave containment or resonance phenomenon, referred to as trapped-fetch waves, has been known for generations, but not always well understood by forecasters. The twofold threat of trapped-fetch waves is that they have the potential for extreme growth, yet are unheralded by leading swell. Conceptual and numerical Lagrangian reference frame experiments on wave containment are presented, illustrating the influence on tropical cyclone ocean waves by three storm parameters: storm speed, wind speed, and fetch length. To further illustrate the concepts and provide real-time application, a simple, desktop Lagrangian trapped-fetch wave model, used for training and operational assessment of trapped-fetch waves, is described in a companion article.

THE IMPACT OF SST COOLING ON TROPICAL CYCLONE BY COUPLED ATMOSPHERIC GLOBAL CLIMATE-SLAB OCEAN-WAVE MODEL

2018 ◽  
Vol 74 (2) ◽  
pp. I_1375-I_1380
Author(s):  
Daisuke URANO ◽  
Tomoya SHIMURA ◽  
Nobuhito MORI ◽  
Ryo MIZUTA
Keyword(s):  
Tropical Cyclone ◽  
Global Climate ◽  
Wave Model ◽  
Ocean Wave ◽  
Sst Cooling ◽  
Ocean Wave Model ◽  
Slab Ocean ◽  
The Impact

A fully-coupled atmosphere-ocean-wave model of the Caspian Sea

2016 ◽  
Vol 107 ◽  
pp. 97-111 ◽  
Author(s):  
Nicolas Bruneau ◽  
Ralf Toumi
Keyword(s):  
Caspian Sea ◽  
Wave Model ◽  
Ocean Wave ◽  
The Caspian Sea ◽  
Ocean Wave Model ◽  
Fully Coupled

scholarly journals Long and Short-Term Simulations of Seto Inland Sea by Coupled Ocean-Wave Model

2013 ◽  
Vol 69 (2) ◽  
pp. I_511-I_515
Author(s):  
Yusuke TANAKA ◽  
Nobuhito MORI ◽  
Junichi NINOMIYA ◽  
Koichi SUGIMATSU ◽  
Hiroshi YAGI ◽  
...  
Keyword(s):  
Wave Model ◽  
Ocean Wave ◽  
Seto Inland Sea ◽  
Short Term ◽  
Ocean Wave Model

An experimental study of source motion synthesis from first arrivals

1963 ◽  
Vol 53 (5) ◽  
pp. 955-963
Author(s):  
Henry N. Pollack
Keyword(s):  
Experimental Study ◽  
Source Function ◽  
Seismic Source ◽  
The Body ◽  
Body Waves ◽  
Fixed Position ◽  
Explosive Source ◽  
Simple Medium ◽  
Surface Ice ◽  
Source Motion

Abstract The motion near a seismic source is synthesized from experimentally obtained seismograms of non-dispersed body waves. The body waves were emitted from an explosive source submerged in a lake with a frozen surface. The seismograms were recorded at several distances by moving the source to a greater depth for each record, while the seismometer remained in a fixed position on the surface ice sheet. All syntheses of the waveform one meter from the source yield the impulsive nature of the source. Deviations between the synthesized one-meter record and the observed one-meter motion are thought to reflect primarily the changing character of the shot medium with depth from the ice. These results indicate that over the short propagation distances (about three wavelengths for the higher frequencies recorded) through the simple medium of this experiment, the observed waveforms and their associated spectra retain characteristics of the source function. The records also yield some information regarding the nature and structure of the elastic medium about the source.

scholarly journals Secondary Microseisms generated by typhoons in the Northwestern Pacific Ocean

2021 ◽  
Author(s):  
Nassima Benbelkacem ◽  
Eléonore Stutzmann ◽  
Martin Schimmel ◽  
Véronique Farra ◽  
Fabrice Ardhuin ◽  
...  
Keyword(s):  
Gravity Waves ◽  
Body Wave ◽  
Ocean Waves ◽  
Body Waves ◽  
Northwestern Pacific ◽  
Northwestern Pacific Ocean ◽  
Wave Reflections ◽  
Source Characteristics ◽  
Beamforming Technique ◽  
The Relationship

<p>Secondary Microseisms (SM) are recorded by seismometers in the period band 3-10 s. They are generated by the interaction of ocean gravity waves of similar frequencies and coming from nearly opposite directions. Typhoons create such ocean waves, and the purpose of this study is to investigate the relationship between typhoons and microseism source characteristics. We focused our study on the Northwestern Pacific and we analyzed seismic signals recorded by the Alaska array and the corresponding storm catalog. While P body waves enable to characterize the amplitude and the localization of the sources, secondary microseisms are dominated by surface waves. Therefore, we apply beamforming technique to the vertical components in order to highlight the weaker body wave signals. This analysis permits us to track the localization of SM sources every 6 hours. Our results show three cases: In the case of one active typhoon, the positions of SM sources are localized close to the typhoon position. In the case of two nearby typhoons acting simultaneously, the SM sources are localized in between the typhoons. Finally, when the typhoon arrives close to the coast, we observe sources generated by ocean wave reflections. In conclusion, the three mechanisms proposed by Ardhuin et al., (2011) are necessary to explain secondary microseisms generated by typhoons.</p>

scholarly journals Evaluating skill of BMKG wave model forecast (Wavewatch-3) with observation data in Indian Ocean (5 – 31 December 2017).

2021 ◽  
Vol 893 (1) ◽  
pp. 012058
Author(s):  
R Kurniawan ◽  
H Harsa ◽  
A Ramdhani ◽  
W Fitria ◽  
D Rahmawati ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Wave Height ◽  
Model Performance ◽  
Forecast Accuracy ◽  
Wave Model ◽  
Ocean Waves ◽  
Observation Data ◽  
Operating Characteristics ◽  
Wave Forecast ◽  
Good For

Abstract Providing Maritime meteorological forecasts (including ocean wave information) is one of BMKG duties. Currently, BMKG employs Wavewatch-3 (WW3) model to forecast ocean waves in Indonesia. Evaluating the wave forecasts is very important to improve the forecasts skill. This paper presents the evaluation of 7-days ahead BMKG’s wave forecast. The evaluation was performed by comparing wave data observation and BMKG wave forecast. The observation data were obtained from RV Mirai 1708 cruise on December 5th to 31st 2017 at the Indian Ocean around 04°14'S and 101°31'E. Some statistical properties and Relative Operating Characteristics (ROC) curve were utilized to assess the model performance. The evaluation processes were carried out on model’s parameters: Significant Wave Height (Hs) and Wind surface for each 7-days forecast started from 00 UTC. The comparation results show that, in average, WW3 forecasts are over-estimate the wave height than that of the observation. The forecast skills determined from the correlation and ROC curves are good for the first- and second-day forecast, while the third until seventh day decrease to fair. This phenomenon is suspected to be caused by the wind data characteristics provided by the Global Forecasts System (GFS) as the input of the model. Nevertheless, although statistical correlation is good for up to 2 days forecast, the average value of Root Mean Square Error (RMSE), absolute bias, and relative error are high. In general, this verifies the overestimate results of the model output and should be taken into consideration to improve BMKG’s wave model performance and forecast accuracy.

PSEUDO GLOBAL WARMING EXPERIMENTS OF TYPHOON HAIYAN USING HIGH-RESOLUTION COUPLED ATOMSPHERE-OCEAN-WAVE MODEL

2021 ◽  
Vol 77 (2) ◽  
pp. I_985-I_990
Author(s):  
Junichi NINOMIYA ◽  
Tetsuya TAKEMI ◽  
Nobuhito MORI
Keyword(s):  
Global Warming ◽  
High Resolution ◽  
Wave Model ◽  
Ocean Wave ◽  
Ocean Wave Model
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