An assessment of wind forcing impact on a spectral wave model for the Indian Ocean

The focus of the present study is the assessment of the impact of wind forcing on the spectral wave model MIKE 21 SW in the Indian Ocean region. Three different wind fields, namely the ECMWF analyzed winds, the ECMWF blended winds, and the NCEP blended winds have been used to drive the model. The wave model results have been compared with in-situ observations and satellite altimeter data. This study also evaluated the performance of the wind products during local phenomenon like sea breeze, since it has a significant impact on the wave prediction in the Indian coastal region. Hence we explored the possibility of studying the impact of diurnal variation of winds on coastal waves using different wind fields. An analysis of the model performance has also been made during high wind conditions with the inference that blended winds generate more realistic wave fields in the high wind conditions and are able to produce the growth and decay of waves more realistically

Cognitive seismic data modelling based successive differential evolution algorithm for effective exploration of oil-gas reservoirs

A cognitive modelling based new inversion method, the successive differential evolution (DE-S) algorithm, is proposed to estimate the Q factor and velocity from the zero-offset vertical seismic profile (VSP) record for oil-gas reservoir exploration. The DE algorithm seeks optimal solutions by simulating the natural species evolution processes and makes the individuals become optimal. This algorithm is suitable for the high-dimensional nonseparable model space where the inversion leads to recognition and prediction of hydrocarbon reservoirs. The viscoelastic medium is split into layers whose thicknesses equal to the space between two successive VSP geophones, and the estimated parameters of each layer span the related subspace. All estimated parameters span to a high dimensional nonseparable model space. We develop bottom-up workflow, in which the Q factor and the velocity are estimated using the DE algorithm layer by layer. In order to improve the inversion precision, the crossover strategy is discarded and we derive the weighted mutation strategy. Additionally, two kinds of stopping criteria for effective iteration are proposed to speed up the computation. The new method has fast speed, good convergence and is no longer dependent on the initial values of model parameters. Experimental results on both synthetic and real zero-offset VSP data indicate that this method is noise robust and has great potential to derive reliable seismic attenuation and velocity, which is an important diagnostic tool for reservoir characterization

Identifikasi dan Pemetaan Lokasi Potensial Energi Gelombang Laut Di Perairan Indonesia

Penelitian ini membahas tentang pemetaan potensi energi gelombang di perairan Indonesia. Penelitian ini dilakukan untuk mengupdate peta potensi energi gelombang yang telah ada, sehingga dapat dijadikan acuan untuk survey lanjutan oleh lembaga pemerintahan dan lembaga riset terkait. Penelitian ini mengkaji dari beberapa aspek yaitu perhitungan menggunakan rumus energi gelombang, perhitungan terkait efisiensi teknologi energi gelombang, perhitungan terkait parameter fisik perairan Indonesia, pembahasan terkait regulasi laut yang ada, serta pembahasan tentang aspek ekonomi. Penelitian ini menggunakan metode inverse distance weight, dimana metode ini digunakan untuk menghitung potensi energi yang ada dari data yang tidak begitu banyak. Data utama yang digunakan adalah data dari hasil ekstraksi citra satelit Altimetri dengan resolusi 1x1 . Hasil dari penelitian ini yaitu perairan di Indonesia memiliki potensi energi gelombang sebesar 717.000 MW. Lokasi perairan Indonesia yang memiliki potensi energi gelombang terbesar terdapat di perairan Provinsi Bengkulu sebesar 600 kW dan perairan Pulau Sumba sebesar 900 kW. Besar potensi tersebut tidak semua dapat dimanfaatkan karena teknologi yang kurang memadai, kondisi fisik lingkungan perairan yang kurang sesuai, serta regulasi laut di Indonesia yang membatasi zona pemanfaatan energi gelombang lau