Judul: Studi Deografi Ikan Belanak (Mugil dussumieri C. V.) dan Ikan Kada (Mugil buchanani Blkr.) di Perairan Segara Anakan, Cilacap, Jawa Tengah
Abstrak: Famili Mugilidae banyak terdapat di pantai pantai Gaerah tropik dan sub-tropik, sebagai contoh sembilan species terdapat di Indonesia. Dua di antara sembilan species tersebut terdapat di Segara Anakan, yaitu Mugil dussumieri C.V. dan Mugil buchanani Blkr. Pendangkalan secara terus menerus di Segara Anakan akan mengakibatkan kerkurangnya areal laguna menjadi daratan di masa mendatang. Seandainya hal ini terjadi maka semua organisme yang hidup, baik yang menetap atau sementara akan terganggu daur hidup dan kehilangan habitatnya. Penelitian ini bertujuan untuk mendapatkan gambaran mengenai parameter-parameter yang dapat membantu dalam pengelolaan perikanan (misalnya struktur kelompok umur; pola pertumbuhan; mortalitas) di laguna Segara Anakan, Cilacap, Jawa Tengah. Metode Bhattacharya (1967) digunakan untuk menentukan jumlah, proporsi, serta nilai tengah kelompok umur. Persamaan pertumbuhan didapatkan berdasarkan prinsip suksesi kohort. Persamaan pertumbuhan von Bertalanfly digunakan untuk menggambarkan persamaan pertumbuhan panjang dan berat ikan belanak. ...
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Judul: Analisa struktur komunitas ikan di Segara Anakan Cilacap
Abstrak: Tujuan penelitian ini adalah untuk mendapatkan informasi yang nyata mengenai struktur komunitas ikan di perairan laguna Segara Anakan dalam rangka pengelolaan sumberdaya perikanan pada perairan tersebut. Penelitian ini dilakukan pada musim kemarau (Agustus sampai dengan September 1983). Penangkapan ikan dengan gill neta dan trap nets dalam unit usaha yang sama besar. Analisa masalah didekati dengan menggunakan indek keanekaragaman jenis dan model distribusi kelimpahan. Hasil penelitian menunjukkan terdapat 45 jenis ikan yang termasuk ke dalam 36 famili. Banyaknya jenis tiap wilayah tidak sama. Mugil dussumieri. Mugil buchanani mempunyai kelimpahan relatif paling tinggi. Walaupun terdapat dugaan bahwa keanekaragaman jenis di laguna Segara Anakan sedang menuju degradasi yang dimulai dari wilayah B, tetapi secara keseluruhan keaneka ragaman dan kemerataan individu per jenisnya masih termasuk tinggi. Perairan laguna Segara Anakan, termasuk tiap wilayahnya, masih berperan dengan baik bagi komunitas ikannya. Hal ini ditunjukkan oleh model distribusi kelimpahan jenisnya yang mengikuti model Preston.
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Judul: Thermal Characteristics and Dynamics of Tropical Cyclone over Western North Pacific Ocean: A Case Study of Typhoon Songda (Chedeng) 2011
Abstrak: The frequent occasion of Tropical Cyclone (TC) over Western North Pacific (WNP) Ocean lies from 10˚N to 26˚N and 121˚E to 170˚E. Sources of TC development come from warm ocean temperature where latent heat is released during condensation processes and subsequently concentrated in the boundary layer. Relative humidity at 850-700 hPa is responsible to produce the most intense storm. Meanwhile, weak vertical wind shear between 850-200 hPa is one of the dynamical factors that lead to the development of TC. Pressure level of 850-200 hPa is chosen to minimize the thermodynamic effect in the lower troposphere. Typhoon Songda (Chedeng in the Philippines) or TSC lasted from May 18th to 30th, 2011 and strengthened into powerful Super Typhoon stage between May 24th and 27th. Long curving track and the exhibition of all sequences of TC life cycle, TSC is then considered as an ideal case of TC. The objective of the study with case of TSC is to investigate the role of thermal characteristics and dynamics on TC intensity. The research is carried out by using Advanced Research of Weather Research and Forecasting model (WRF ARW model) version 3.3. Two domains are employed in the model. The first domain situate from 02˚N to 40˚N and 118˚E to 149˚E and cover spatial resolution () of 33.1 km. The second domain situate from 09˚N to 27˚N and 119˚E to 132˚E with of 11 km. Timestep of the model () is 120 seconds. The model is supported by the following physical parameterization, i.e., Yonsei University Scheme (YSU) in the boundary layer, Kain-Fritsch scheme (KF) in the cumulus, and WRF Single-Moment 3-class scheme in the microphysics. Initial meteorological condition prior to the formation of the cyclone is generated using WRF ARW standard-release model. Sensitivity of the model output is obtained from a selected single-parameter change scenarios, namely, 10 % to 20 % decrease and increase of wind shear initial data at 850-200 hPa, and by 10 % to 20 % decrease of relative humidity initial data at 850-700 hPa. The result showed that the negative correlations between wind shear and intensity are found in wind shear scenarios. Wind shears of 10 ms-1 which lead to strengthening of the wind intensity in the early period of Typhoon development are found in wind shear scenarios. The effect of wind shear changes on wind intensity is statistically significant in the 20 % wind shear scenarios. During mature stage, weak wind intensity occurred when wind shear increase as given in the WRF standard-release and the 20 % decreasing scenario. Different situation is found in the 20 % increasing scenario where wind shear tend to weak and lead to strong wind intensity at this stage. Meanwhile, the reduction of moisture supply at 850-700 hPa resulting from 20 % decreasing relative humidity play a major role in the weakening of wind intensity and reduces mechanical energy of the cycle process as much as 300 J kg-1.
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