L. Sagala, Sophia
Pusat Riset Kelautan

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APLIKASI MODEL NUMERIK KARAKTERISTIK GELOMBANG UNTUK KAJIAN KESESUAIAN LAHAN PENGEMBANGAN BUDIDAYA LAUT DI SITUBONDO, JAWA TIMUR Risandi, Johan; L. Sagala, Sophia; S. Pranowo, Widodo
Jurnal Kelautan Nasional Vol 10, No 1 (2015): APRIL
Publisher : Pusat Riset Kelautan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15578/jkn.v10i1.11

Abstract

Model numerik XBeach telah digunakan untuk mensimulasikan penjalaran gelombang laut di perairan Klatakan, Situbondo, Jawa Timur dan hasilnya dipakai untuk analisis kesesuaian lahan budidaya dengan Keramba Jaring Apung (KJA). Data yang digunakan untuk pemodelan ini adalah data batimetri yang diperoleh dari pengukuran langsung, serta gelombang dan angin dari Badan Meteorologi Klimatologi dan Geofisika, dan National Centers for Environmental Prediction-National Oceanic and Atmospheric Administration (NCEP-NOAA) Amerika Serikat. Hasil analisis menunjukkan bahwa tinggi gelombang signifikan perairan Situbondo adalah 0,3 m dengan periode gelombang 4,1 detik dominan dari arah timur sedangkan angin dominan datang dari arah barat laut. Pembudidaya perlu mewaspadai kemungkinan gelombang dengan tinggi mencapai 1,5 m dan angin kuat dengan kecepatan lebih dari 16 m/detik yang terjadi pada awal dan pertengahan tahun. Validasi model dengan perhitungan analitik mengindikasikan XBeach telah melakukan over-estimasi perhitungan tinggi gelombang pada daerah studi dengan kesalahan relatif rata-rata sebesar 16,22% yang diduga disebabkan oleh perbedaan pendekatan pada kedalaman dimana proses shoaling terjadi. Klasifikasi kesesuaian lahan menunjukkan adanya sebaran daerah sangat sesuai hingga tidak sesuai untuk budidaya dengan KJA pada perairan tersebut. Hasil tersebut diverifikasi dengan citra Ikonos melalui Google Earth, dimana terlihat bahwa KJA para pembudidaya terletak di perairan yang dikategorikan sangat sesuai untuk lahan budidaya dengan tinggi gelombang di area tersebut kurang dari 0.6 meter. [Title : THE APPLICATION OF WAVE CHARACTERISTIC NUMERICAL MODEL FOR SITE SELECTION OF MARINE AQUACULTURE DEVELOPMENT IN SITUBONDO, EAST JAVA ] Xbeach numerical model has been used to simulate wave propagation in Klatakan – Situbondo, East Java and the results were used to analyze the site suitability for mariculture using Floating Net Cage (FNC). Parameters used in the model were bathymetric which was obtained from direct measurement, as well as wave and wind data which were obtained from, Indonesian Agency for Meteorology, Climatology and Geophysics, and National Centers for Environmental Prediction-National Oceanic and Atmospheric Administration, respectively. The results showed that a significant wave height recorded in the study area was 0.3 m with wave period of 4.1 s, propagating dominantly from East direction. On the other hand, the wind dominantly moved from north to west direction. The farmers, therefore, need to increase their awareness toward possible high waves of 1.5 m and winds of more than 16 m/s occurred in the beginning and middle of the year. Model validation using analytical approach indicated XBeach has overestimated wave height calculation on the study area with mean relative error of 16,22% due to different approach in depth at which shoaling process occurred. The site classification analysis showed the area distribution for FNC installation varied from unsuitable to very suitable.The result is verified using Ikonos satellite imagery trough Google Earth. It shows that those FNC are located inside the area which is categorized as very feasible for mariculture with the wave height is less than 0.6 m. 
Meteorological and physical conditions of Salt Pan Areas with Filtering-Threaded Technology (TUF) in Cirebon Regency, Indonesia Bramawanto, Rikha; L. Sagala, Sophia
Jurnal Segara Vol 12, No 2 (2016): Agustus
Publisher : Pusat Riset Kelautan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15578/segara.v12i2.7678

Abstract

Salt pans in Indonesia are commonly set in batch operation and highly depend on the meteorological condition. Moreover, the common salt pans are considerably limited in the area (averagely 0.5-1 Ha) as it is not organized by industries or governments; local farmers instead. However, with such confinement, there are some salt pans particularly with filtering-threaded technology system (TUF system) that successfully produce salt with high production (>100 tons/Ha/season) and grade-1 quality. The present study was aimed to get insight on the meteorological condition at the salt pans using TUF system and the physical condition of the sea brine obtained from the TUF in the local salt pans in Cirebon Regency. Measurements on temperatures (air, brine and soil), humidity, wind direction and speed, brine conductivity, brine density and salinity were conducted at the pre-crystallizer pond, brine storage pond, channels, the condenser, and the reservoir. The meteorological parameters were recorded hourly using Automatic Weather Station and the data were taken during 49 hours ly, from August 26-28, 2014 started at 04.00 pm. Meanwhile, the physical parameters of the brine were measured every three hours using water quality meter. The results showed that the meteorological condition, brine physical condition, and the process occurred during salt production were still in agreement and met the theoretical condition or modeling. Even though the relative humidity and some wind speed in the present study area were out of the standard criteria recommended (5m/s for wind speed), the study showed that salt still can be produced in condition of relative humidity (52-88%), wind speed (0.2-5.7 m/s), and ambient temperature (23.2-32.4 oC). Interestingly, it is found that brine thickness and volume could be adjusted to get an optimum temperature of brine (reached 36.2 oC), in order to enhance the evaporation process. The highest soil temperature (34.7 oC) was found at 15.00 in the pre-crystallizer ponds. Meanwhile, the lowest temperature (26.7oC) was found early morning at 04.00 in the reservoir pond. Brine in the pre-crystallizer had highest thermal storage capacity during daytime (06.00-16.00), whereas soil in the pre-crystallizer tended to store heat during the nighttime (18.00-22.00). Brine and soil temperature fluctuation indicate that solar irradiation and convection process transferring heat energy from soil to brine occurs and also took an important part in the evaporation process. It therefore can be concluded that by understanding the condition of meteorology at the salt pan areas and the brine characteristic obtained, the appropriate technology resulting high-quality and quantity salt production could be devised.