Numerical Study of Wave Spectrum Transformation over Fringing Coral Reefs

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簡歷

基本資料

Project title

Code/計畫編號

MOST103-2218-E032-002

Translated Name/計畫中文名

數值研究波浪於珊瑚裙礁之波譜變化

Project Coordinator/計畫主持人

Shih-Feng Su

Funding Organization/主管機關

National Science and Technology Council

Department/Unit

Department of Water Resources and Environmental Engineering Tamkang University

Website

https://www.grb.gov.tw/search/planDetail?id=8176082

Year

2014

Start date/計畫起

01-01-2014

Expected Completion/計畫迄

31-12-2014

Bugetid/研究經費

584千元

ResearchField/研究領域

環境科學
海洋科學

在海洋環境中，珊瑚礁是一個珍貴的天然資源，它提供空間給予多元的海洋生物棲息並緩衝波浪能量讓沙灘免於被侵蝕。珊瑚礁地形有別於平緩的沙質海岸，一般是由寬敞且水淺的粗糙礁石平台延伸至外海後急降至深水，水動力特性受到表面波浪與複雜地形交互作用影響而變得很複雜。雖然許多波譜模式能成功地描述波高與波揚在珊瑚礁的分布過程，但是低頻亞重力波之預測準確性仍然是一個挑戰，而這個低頻波浪在淺水的珊瑚礁環境是主要的波浪成分。這是因為模式在預測非線性波與波能量交互作用之機制並未完善。本計畫之目的是利用根據 Boussinesq 方程式之非線性波浪模式 FUNWVE-TVD 來研究波浪在珊瑚礁地形之變化過程，並利用水工模型試驗數據予以驗證模式結果。利用一維波浪實驗與模式來探討不規則波通過不同潮位、礁坡及底床粗糙度之波譜變化，並評估模式預測低頻亞重力波發展及衰減之能力。進一步，利用二維實驗比較波浪引起之流場空間變化。有了模式參數率定與系統性地估算，模式將能應用於了解氣候變遷下極端波浪與海岸溢淹對珊瑚礁環境造成之衝擊。 Coral reefs are precise natural resources in ocean environments. They provide habitats for a large number of marine species and protect shoreline from erosion by buffering wave energy. Geometric shapes of coral reefs, differing from sloping sandy beaches, are commonly characterized by wide-shallow platforms with rough surface that sharply drop into deep water. Hydrodynamic processes are therefore more complicated due to the interaction between surface waves and the complex reef topographies. Although numerous spectral models have succeeded in predicting wave height and wave setup over reefs, the accuracy in low-frequency infragravity waves, known to be the dominant wave components on shallow reefs, remains as one of the most challenge. This is because the mechanism of nonlinear wave-wave interactions is poorly resolved in these models. The aim of this project is to study wave transformation over reefs by a nonlinear wave model FUNWAVE-TVD based on Boussinesq equations. Model results will be validated using wave data measured in one-dimensional and two-dimensional laboratory experiments. Influences of tidal levels, reef slopes and the roughness of bottom on wave spectral transformation over reefs will be investigated by comparing with the one-dimensional experiments. The model capability in simulating the evolution and dissipation of infragravity motions over reefs will be evaluated as well. Furthermore, wave-induced nearshore circulation in two-dimensional spatial variation will be simulated by comparing with the experiments. With refining the parameterization and systematic evaluations, the model will be applied to understand the effects of climate change on extreme waves and coastal flooding for reef environments.

Keyword(s)

珊瑚礁
氣候變遷
波譜
亞重力波
波揚
流場
Coral reef
climate change
wave spectra
infragravity waves
wave setup
circulation

DSpace CRIS

Numerical Study of Wave Spectrum Transformation over Fringing Coral Reefs

基本資料

Description