Judul: Identification of Forest Fire Severity and Estimation of Carbon Emissions in The Mount Ungaran Forest Area, Central Java
Abstrak: Kebakaran hutan yang terjadi di dataran tinggi di wilayah tropis mengakibatkan peningkatan ancaman terhadap keberadaan hutan. Kawasan Hutan Gunung Ungaran (KHGU) merupakan hutan pegunungan yang pernah terjadi kebakaran hutan pada tahun 2018. Penelitian ini bertujuan menganalisis tingkat keparahan kebakaran hutan, menganalisis komposisi vegetasi, dan mengukur biomassa, karbon, serta emisi karbon yang dihasilkan pascakebakaran di KHGU. Metode pada penelitian ini menggunakan data primer dan data sekunder. Hasil penelitian menunjukkan bahwa tingkat keparahan kebakaran hutan di Puncak Botak terbagi menjadi tiga kelas yaitu berat, sedang, dan tidak terbakar. Luas area tingkat keparahan kebakaran untuk kelas berat, sedang, dan tidak terbakar masing-masing seluas 15,1 ha, 22,1 ha, dan 3.830,2 ha. Jenis yang dominan di Puncak Botak yaitu alang-alang (Imperata cylindrica) sedangkan di Puncak Ungaran pada tingkat semai yaitu blabahan (Brachiaria paspaloides), tingkat pancang yaitu kayu tejo (Manglietia glauca), tingkat tiang dan pohon yaitu kayu sarangan (Castanopsis argentea). Jumlah biomassa dan karbon di Puncak Botak diperoleh masing-masing sebesar 53,95 ton/ha; 25,34 ton/ha sedangkan di Puncak Ungaran diperoleh sebesar 5,55 ton/ha; 2,56 ton/ha. Emisi karbon yang dihasilkan akibat kebakaran di Puncak Botak yaitu sebesar 0,022 tonCO₂. Kata kunci: Gunung Ungaran, Puncak Botak, Puncak Ungaran, indeks NBR, Sentinel-2A, Forest fires occurring at high altitudes in the tropics pose an increasing threat to the existence of forests. The Mount Ungaran Forest Area (KHGU) is a mountain forest that experienced forest fires in 2018. This study aimed to analyse the severity of forest fires, assess vegetation composition, and measure post-fire biomass, carbon and carbon emissions in KHGU. This research method used primary data and secondary data. The results showed that the severity of forest fires in Botak Peak was divided into three classes: heavy, medium, and unburned. The area of fire severity for heavy, moderate and unburnt classes are 15,1 ha, 22,1 ha and 3.830,2 ha respectively. The dominant species at Botak Peak is alang-alang (Imperata cylindrica) while at Ungaran Peak at the seedling level is blabahan (Brachiaria paspaloides), stake level is tejo wood (Manglietia glauca), pole and tree level is sarangan wood (Castanopsis argentea). The amount of biomass and carbon at Botak Peak was 53,95 tonnes/ha; 25,34 tonnes/ha respectively while at Ungaran Peak it was 5,55 tonnes/ha; 2,56 tonnes/ha. The carbon emissions generated by the fire on Botak Peak are 0,022 tonnesCO₂. Keywords: Mount Ungaran, Botak Peak, Ungaran Peak, NBR index, Sentinel-2A
Keyword: Mount Ungaran, Botak Peak, Ungaran Peak, NBR index, Sentinel-2A

Judul: Estimation of carbondioxide Emission Of Forest and Land Fire in Tanjung Jabung Timur Regency,  Jambi Province
Abstrak: Kebakaran lahan dan hutan berkontribusi besar pada peningkatan emisi karbon di atmosfer bumi. Emisi karbon ini dapat berdampak buruk terhadap lingkungan. Penelitian ini difokuskan dalam estimasi luas area kebakaran dan estimasi emisi karbon di Kabupaten Tanjung Jabung Timur, Provinsi Jambi. Penelitian dilakukan dengan metode digital untuk menduga luas area terbakar. Peta luasan kebakaran diperoleh dengan menggunakan citra Landsat 8 OLI/TIRS Tier 2. Penghitungan emisi karbondioksida menggunakan persamaan Seiler dan Crutzen. Fluktuasi jumlah hotspots yang terdeteksi pada tahun 2016-2020 menyebabkan perbedaan luas area yang terbakar, jumlah hotspots tertinggi diperoleh pada tahun 2019, sebanyak 6.839 titik pada tanah gambut dan 1.529 titik pada tanah mineral dan merupakan area terluas yang terbakar yaitu sebesar (7.758,17 ha) pada tanah gambut dan (9.434,56 ha) pada tanah mineral. Penelitian ini menunjukkan bahwa besarnya emisi dari suatu wilayah dipengaruhi oleh kandungan biomassa dan luasan area terbakar. Emisi gas CO2 terbesar diperoleh pada tahun 2019 sebesar 507.433,1 ton CO2 pada tanah gambut dan 103.048,2 ton CO2 pada tanah mineral ., Land and forest fires contribute greatly to the increase in carbon emissions in the earth's atmosphere. These carbon emissions may bring negative impacts on the environment. This research is focused on estimating the burnt area and estimating carbon emissions in Tanjung Jabung Timur Regency, Jambi Province. The research was conducted using a digital method to estimate the burned area. A burnt area map was made using Landsat 8 OLI/TIRS Tier 2 images. The carbon emission was calculated by using Seiler and Crutzen (1980) equation. Fluctuations in the number of hotspotss detected in 2016-2020 led to differences in the area burned during the period. The highest number of hotspots found in 2019, detected as many as 6.839 points on peat lands and 1.529 points on mineral soil and was the largest area burned was (7.758,17 ha) on peat lands and (9.343.56 ha) on mineral soil . This research proves that the amount of emissions from an area is greatly influenced by the biomass and burnt area. The largest CO2 gas emissions was found in 2019 which was 507.433,1 ton CO2 on peat lands and 103.048,2 ton CO2 on mineral soils.
Keyword: carbondioxide emission, hotspots, land and forest fire, Tanjung Jabung Timur

Judul: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
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