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All Journal Journal of Oceanography Jurnal Statistika Universitas Muhammadiyah Semarang Journal of Marine Research
Alfi Satriadi
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Agriculture, Biological Sciences & Forestry Decision Sciences, Operations Research & Management Earth & Planetary Sciences Environmental Science

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PEMODELAN ARIMA UNTUK PRAKIRAAN KENAIKAN MUKA AIR LAUT DAN DAMPAKNYA TERHADAP LUAS SEBARAN ROB TAHUN 2020 DI SEMARANG Dwi Haryo Ismunarti; Alfi Satriadi; Azis Rifai
Jurnal Statistika Universitas Muhammadiyah Semarang Vol 2, No 2 (2014): Jurnal Statistika
Publisher : Program Studi Statistika, Fakultas Matematika dan Ilmu Pengetahuan Alam, Universitas Muham

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (949.733 KB) | DOI: 10.26714/jsunimus.2.2.2014.%p

Abstract

Muka air laut dalam istilah pasang surut disebut  mean sea level (MSL) yaitu rata-rata jumlah seluruh ketinggian pasang yang diamati.  Pemodelan untuk membuat prakiraan kenaikan muka air laut di Semarang telah banyak dilakukan dengan pendekatan yang hanya mempertimbangkan pola trend yaitu jika terjadi kenaikan secara sekuler dalam jangka panjang dari data. ARIMA (autoregressive/integrated/moving average) adalah metode peramalan meliputi dua hal yaitu analisis pola deret data dan seleksi model yang paling cocok dengan data. Terdapat 4 pola data deret berkala yaitu : pola horisontal bila data berfluktuasi disekitar rata-rata, pola musiman bila  deret data dipengaruhi faktor musiman, pola dari deret berkala akan diulang-ulang dalam selang waktu yang tetap,  pola siklis jika deret data dipengaruhi oleh fluktuasi jangka panjang dan pola trend jika terjadi kenaikan atau penurunan secara sekuler dalam jangka panjang. Model ARIMA diturunkan berdasarkan SML sementara harian. Data diperoleh dari BMKG Semarang. Hasil menunjukkan tipe pasang surut di perairan Semarang  diklasifikasikan ke dalam tipe pasang surut campuran condong ke harian ganda dengan nilai Formzahl 1,12.  Elevasi muka air laut rata – rata (MSL) 59,9261 cm, muka air tinggi tertinggi (HHWL) 117,38 cm dan muka air rendah terendah (LLWL) 24,71 cm. Model terbaik ARIMA (0,1,1) yaitu .  Hasil penghitungan deret waktu MSL sejati tahunan menunjukkan laju kenaikan MSL sejati tahunan di Kota Semarang sebesar 1,42 cm per tahun.
Studi Hubungan Kerapatan Vegetasi Lamun dengan Laju Sedimentasi di Perairan Teluk Awur dan Bandengan Jepara Pada Periode Juni – Juli 2012 Nursanti Nursanti; Ita Riniatsih; Alfi Satriadi
Journal of Marine Research Vol 2, No 3 (2013) : Journal of Marine Research
Publisher : Departemen Ilmu Kelautan, Fakultas PerikanJurusan Ilmu Kelautan, Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1519.429 KB) | DOI: 10.14710/jmr.v2i3.3128

Abstract

Teluk Awur and Bandengan waters are located in Jepara which have different conditions and also the waters are still good for seagrass growth. Seagrass has one physical function as a sediment catcher in coastal waters. The sedimentation rate in the Teluk Awur and Bandengan waters affected by seagrass density, flow velocity, and sediment composition. The purpose of this research is to determine the relationship of seagrass vegetation density with the rate of sedimentation in the Teluk Awur and Bandengan waters, Jepara. This reaserch was conducted in June-July 2012. in the Teluk Awur waters discovered 6 genus such as Enhalus, Thalassia, Thalassodendron, Cymodocea, Halodule, and Syringodium, with an average value of density 198.03 individu/m2. While Bandengan waters was found 7 genus such as Enhalus, Thalassia, Thalassodendron, Cymodocea, Halodule, Syringodium and Halophila, with average value of density 457.1 individu/m2. The results showed that the average value of sedimentation rate in the Teluk Awur waters 438.74 g/m2/week, while the Bandengan waters 667.42 g/m2/week. The R2 value of relationship between Seagrass density with the sedimentation rate in the Teluk Awur waters 0.566. While the R2 of Bandengan waters 0.073. The Teluk Awur waters contain a little lanau sediment so it has a little sedimenation. Bandengan waters contain higher lanau sediment so it has more sedimentation.
KAJIAN KERENTANAN BENCANA TSUNAMI DI PESISIR KABUPATEN KULON PROGO PROVINSI D. I. YOGYAKARTA Ari Widyawati; Gentur Handoyo; Alfi Satriadi
Journal of Marine Research Vol 2, No 2 (2013) : Journal of Marine Research
Publisher : Departemen Ilmu Kelautan, Fakultas PerikanJurusan Ilmu Kelautan, Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (200.015 KB) | DOI: 10.14710/jmr.v2i2.2772

Abstract

Coastal of Kulon Progo Regency is located in the southern coastal area of Java island that potentially vulnerable to tsunami disaster because of its geographical position that directly opposite the Indian Ocean and the meeting place of two tectonic plates, the Eurasian plate and the Indo- Australian plate which is tectonically very active and can be tsunami source. Identification of tsunami vulnerable areas in Kulon Progo Regency is a disaster mitigation step to minimize the negative impact of the tsunami. The purpose of this research is to map the vulnerability of the environment to the tsunami in Kulon Progo Regency coastal. There are five classes of tsunami vulnerabilities in Kulon Progo Regency coastal is the particularly vulnerable class 7.77 km2, 19.82 km2 vulnerable class, the class is quite vulnerable 33.98 km2, 51.38 km2 less vulnerable class, and the class is not vulnerable 31.19 km2 . The area included in very susceptible and vulnereable class in the village of Glagah, Jangkaran, Karang Sewu, Banaran, Sindutan, Palihan, Garongan, Pleret, and Bugel. The class are quit vulnerable, less vulnerable, and not vulnerable include around the village areas of reserarch in Galur, Panjatan, Wates, and Temon district.
SEBARAN NITRAT DAN FOSFAT SECARA HORIZONTAL DI PERAIRAN PANTAI KECAMATAN TUGU, SEMARANG TAHUN 2012 DAN 2013 Pahlawarni Girsang; Muslim Muslim; Alfi Satriadi
Journal of Oceanography Vol 2, No 4 (2013)
Publisher : Program Studi Oseanografi, Jurusan Ilmu Kelautan, Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (2097.364 KB)

Abstract

ABSTRAKKondisi perairan di perairan Tugu Semarang menunjukkan bahwa tipe pasang surut yang terjadi adalah campuran condong ke harian tunggal. Konsentrasi nitrat dan fosfat ketika surut berkisar 0,288 - 0,342 mg/L dan 0,127-0,200 mg/L, dan ketika pasang 0,283 - 0,337 mg/L dan 0,150-0,175 mg/L. Persebaran nitrat dan fosfat yang terjadi saat surut lebih tinggi konsentrasinya dibanding pada saat pasang. Arus tidak terlalu mempengaruhi pola sebaran nitrat dan fosfat, tetapi penurunan konsentrasi nitrat dan fosfat terjadi akibat adanya pengenceran. 
Co-Authors Ari Widyawati Azis Rifai Dwi Haryo Ismunarti Gentur Handoyo Ita Riniatsih Muslim Muslim Nursanti Nursanti Pahlawarni Girsang