Influence of tropical cyclones on the 100‐year return period wave height—A study based on 39‐year long ERA5 reanalysis data

This study aims to analyze the effect of the differences in intensity and track of tropical cyclones upon significant wave heights and direction of ocean waves in the southeast Indian Ocean. We used the tropical cyclone data from Japan Aerospace Exploration Agency (JAXA) starting from December 1997 to November 2017. The significant wave height and wave direction data are reanalysis data from Copernicus Marine Environment Monitoring Service (CMEMS), and the mean sea level pressure, surface wind speed, and wind direction data are reanalysis data from European Center for Medium-Range Weather Forecasts (ECMWF) from December 1997 to November 2017. The results show that the significant wave height increases with the increasing intensity of tropical cyclones. Meanwhile, the direction of the waves is influenced by the presence of tropical cyclones when tropical cyclones enter the categories of 3, 4, and 5. Tropical cyclones that move far from land tend to have higher significant wave height and wider affected areas compared to tropical cyclones that move near the mainland following the coastline

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Wave Force Characteristics of Large-Sized Offshore Wind Support Structures to Sea Levels and Wave Conditions

Applied Sciences ◽

10.3390/app9091855 ◽

2019 ◽

Vol 9 (9) ◽

pp. 1855

Author(s):

Youn-Ju Jeong ◽

Min-Su Park ◽

Jeongsoo Kim ◽

Sung-Hoon Song

Keyword(s):

Shallow Water ◽

Wave Height ◽

Wave Force ◽

Diffraction Effect ◽

Support Structures ◽

Sea Levels ◽

Irregular Wave ◽

Long Period ◽

Short Period ◽

Period Wave

This paper presents the results of wave force tests conducted on three types of offshore support structures considering eight waves and three sea levels to investigate the corresponding wave forces. As a result of this study, it is found that the occurrence of shoaling in shallow water induces a significant increase of the wave force. Most of the test models at the shallow water undergo a nonlinear increase of the wave force with higher wave height increasing. In addition, the larger the diameter of the support structure within the range of this study, the larger the diffraction effect is, and the increase in wave force due to shoaling is suppressed. Under an irregular wave at the shallow water, the wave force to the long-period wave tends to be slightly higher than that of the short period wave since the higher wave height component included in the irregular wave has an influence on the shoaling. In addition, it is found that the influence of shoaling under irregular wave becomes more apparent in the long period.

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Long-Term and Seasonal Trends in Global Wave Height Extremes Derived from ERA-5 Reanalysis Data

Journal of Marine Science and Engineering ◽

10.3390/jmse8121015 ◽

2020 ◽

Vol 8 (12) ◽

pp. 1015

Author(s):

Alicia Takbash ◽

Ian R. Young

Keyword(s):

Southern Hemisphere ◽

Wave Height ◽

Significant Wave Height ◽

Reanalysis Data ◽

Extreme Value Analysis ◽

Winter Storms ◽

Value Analysis ◽

Weather Forecasts ◽

Significant Wave

A non-stationary extreme value analysis of 41 years (1979–2019) of global ERA5 (European Centre for Medium-Range Weather Forecasts Reanalysis) significant wave height data is undertaken to investigate trends in the values of 100-year significant wave height, Hs100. The analysis shows that there has been a statistically significant increase in the value of Hs100 over large regions of the Southern Hemisphere. There have also been smaller decreases in Hs100 in the Northern Hemisphere, although the related trends are generally not statistically significant. The increases in the Southern Hemisphere are a result of an increase in either the frequency or intensity of winter storms, particularly in the Southern Ocean.

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A Method to Implement the Random Signals for Time Varying Offshore Wave Height During Storm Condition in an Intra-Wave Period Wave Model

Volume 2: Ocean Engineering and Polar and Arctic Sciences and Technology ◽

10.1115/omae2006-92435 ◽

2006 ◽

Author(s):

Yuliang Zhu ◽

Shunqi Pan ◽

Premanandan T. Fernando ◽

Xiaoyan Zhou

Keyword(s):

Wave Height ◽

Wave Model ◽

Peak Frequency ◽

Wave Period ◽

Storm Event ◽

Time Varying ◽

Wave Heights ◽

Offshore Wave ◽

Storm Condition ◽

Period Wave

In this paper, a method to implement the surface elevation at the offshore boundary during storm conditions is presented in the intra-wave period wave model. At storm condition, the offshore incident significant wave height is time varying. In the case of time varying incident wave height, the JONSWAP energy spectrum can be manipulated as follows: H1/32s(f). s(f) is the energy density function for a unit wave height. During a storm event not only the offshore boundary significant wave heights but also the peak frequency varies. If we choose a mean peak frequency during a storm event, s(f) can be calculated for the mean peak frequency for the storm event. The amplitudes of the component waves for the random signals are calculated from the unit energy density function s(f), and the phase angle of the component wave, So we can numerically generate surface elevation time series for the time varying offshore wave heights. The method was verified in the intra-wave period wave model using field measurements at Sea Palling site Norfolk UK.

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Comparison of Reanalysis Data Sets to Comprehend the Evolution of Tropical Cyclones Over North Indian Ocean

Earth and Space Science ◽

10.1029/2019ea000978 ◽

2020 ◽

Vol 7 (2) ◽

Cited By ~ 2

Author(s):

P. Malakar ◽

A.P. Kesarkar ◽

J.N. Bhate ◽

V. Singh ◽

A. Deshamukhya

Keyword(s):

Indian Ocean ◽

Tropical Cyclones ◽

Reanalysis Data ◽

North Indian Ocean ◽

Data Sets

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Estimations of statistical dependence as joint return period modulator of compound events. Part I: storm surge and wave height

10.5194/nhess-2017-177 ◽

2017 ◽

Cited By ~ 1

Author(s):

Thomas I. Petroliagkis

Keyword(s):

Storm Surge ◽

Wave Height ◽

Return Period ◽

Flood Hazard ◽

Joint Probability ◽

Irish Sea ◽

Statistical Dependence ◽

Joint Return ◽

Compound Events ◽

Joint Return Period

Abstract. The possibility of utilising statistical dependence methods in coastal flood hazard calculations is investigated, since flood risk is rarely a function of just one source variable but usually two or more. Source variables in most cases are not independent as they may be driven by the same weather event, so their dependence, which is capable of modulating their joint return period, has to be estimated before the calculation of their joint probability. Dependence and correlation may differ substantially from one another since dependence is focused heavily on tail (extreme) percentiles. The statistical analysis between surge and wave is performed over 32 river ending points along European coasts. Two sets of almost 35-year hindcasts of storm surge and wave height were adapted and results are presented by means of analytical tables and maps referring to both correlation and statistical dependence values. Further, the top 80 compound events were defined for each river ending point. Their frequency of occurrence was found to be distinctly higher during the cold months while their main low-level flow characteristics appear to be mainly in harmony with the transient nature of storms and their tracks. Overall, significantly strong values of positive correlations and dependencies were found over the Irish Sea, English Channel, south coasts of the North Sea, Norwegian Sea and Baltic Sea, with compound events taking place in a zero-lag mode. For the rest, mostly positive moderate dependence values were estimated even if a considerable number of them had correlations of almost zero or even negative value.

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Dehydration and low ozone in the tropopause layer over the Asian monsoon caused by tropical cyclones: Lagrangian transport calculations using ERA-Interim and ERA5 reanalysis data

Atmospheric Chemistry and Physics ◽

10.5194/acp-20-4133-2020 ◽

2020 ◽

Vol 20 (7) ◽

pp. 4133-4152 ◽

Cited By ~ 5

Author(s):

Dan Li ◽

Bärbel Vogel ◽

Rolf Müller ◽

Jianchun Bian ◽

Gebhard Günther ◽

...

Keyword(s):

Boundary Layer ◽

Water Vapour ◽

Tropical Cyclones ◽

Summer Monsoon ◽

Asian Summer Monsoon ◽

Deep Convection ◽

Reanalysis Data ◽

Trajectory Calculations ◽

Asian Summer ◽

The Western Pacific

Abstract. Low ozone and high water vapour mixing ratios are common features in the Asian summer monsoon (ASM) anticyclone; however, low ozone and low water vapour values were observed near the tropopause over Kunming, China, within the ASM using balloon-borne measurements performed during the SWOP (sounding water vapour, ozone, and particle) campaign in August 2009 and 2015. Here, we investigate low ozone and water vapour signatures in the upper troposphere and lower stratosphere (UTLS) using FengYun-2D, FengYun-2G, and Aura Microwave Limb Sounder (MLS) satellite measurements and backward trajectory calculations. Trajectories with kinematic and diabatic vertical velocities were calculated using the Chemical Lagrangian Model of the Stratosphere (CLaMS) trajectory module driven by both ERA-Interim and ERA5 reanalysis data. All trajectory calculations show that air parcels with low ozone and low water vapour values in the UTLS over Kunming measured by balloon-borne instruments originate from the western Pacific boundary layer. Deep convection associated with tropical cyclones over the western Pacific transports ozone-poor air from the marine boundary layer to the cold tropopause region. Subsequently, these air parcels are mixed into the strong easterlies on the southern side of the Asian summer monsoon anticyclone. Air parcels are dehydrated when passing the lowest temperature region (< 190 K) at the convective outflow of tropical cyclones. However, trajectory calculations show different vertical transport via deep convection depending on the employed reanalysis data (ERA-Interim, ERA5) and vertical velocities (diabatic, kinematic). Both the kinematic and the diabatic trajectory calculations using ERA5 data show much faster and stronger vertical transport than ERA-Interim primarily because of ERA5's better spatial and temporal resolution, which likely resolves convective events more accurately. Our findings show that the interplay between the ASM anticyclone and tropical cyclones has a significant impact on the chemical composition of the UTLS during summer.

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Estimating return period wave heights and wind speeds using a seasonal point process model

Coastal Engineering ◽

10.1016/s0378-3839(97)00016-1 ◽

1997 ◽

Vol 31 (1-4) ◽

pp. 305-326 ◽

Cited By ~ 41

Author(s):

I.D. Morton ◽

J. Bowers ◽

G. Mould

Keyword(s):

Point Process ◽

Return Period ◽

Process Model ◽

Point Process Model ◽

Wind Speeds ◽

Wave Heights ◽

Period Wave

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The Equivalent Power Storm Model for Long-Term Predictions of Extreme Wave Events

Volume 2: Structures, Safety and Reliability ◽

10.1115/omae2009-79597 ◽

2009 ◽

Cited By ~ 2

Author(s):

Francesco Fedele ◽

Felice Arena

Keyword(s):

Wave Height ◽

Return Period ◽

Shape Parameter ◽

Extreme Wave ◽

Maximum Wave Height ◽

Wave Measurements ◽

Sea Storm ◽

Storm Model ◽

Good Agreement

We present the Equivalent Power Storm (EPS) model as a generalization of the Equivalent Triangular Storm (ETS) model of Boccotti for the long-term statistics of extreme wave events. In the EPS model, each actual storm is modeled in time t by a power law ∼|t−t0|λ, where λ is a shape parameter and t0 is the time when the storm peak occurs. We then derive the general expression of the return period R(Hs > h) of a sea storm in which the maximum significant wave height Hs exceeds a fixed threshold h as function of λ. Further, given the largest wave height Hmax, we identify the most probable storm in which the largest wave occurs and derive an explicit expression for the return period R(Hmax >H) of a storm in which the maximum wave height exceeds a given threshold H. Finally, we analyze wave measurements retrieved from two of the NOAA-NODC buoys in the Atlantic and Pacific oceans and find that the EPS predictions are in good agreement with those from the ETS model.

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