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VARIABILITY OF SATELLITE-OBSERVED SEA SURFACE HEIGHT IN THE TROPICAL INDIAN OCEAN: COMPARISON OF EOF AND SOM ANALYSIS Iskandar, Iskhaq
Makara Journal of Science Vol. 13, No. 2
Publisher : UI Scholars Hub

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

Weekly sea surface height (SSH) in the tropical Indian Ocean (20°S - 20°N) was analyzed for the period of January 1993 – December 2007 using an empirical orthogonal function (EOF) and a self-organizing maps (SOM) analysis. The EOF analysis identifies four patterns and three of them are contained in the SOM patterns. The SOM, on the other hand, characterizes the sea level variability, which shows twenty-five patterns. The patterns with low (high) sea surface height anomaly (SSHA) in the southern (northern) hemisphere associated with the monsoonal winds dominate the variation in both two methods. The SOM is also able to separate typical patterns associated with the ENSO and or the Indian Ocean Dipole (IOD) events. Low SSHA occupied the western half of the basin while high SSHA loaded in the eastern basin when the La Niña event is taking place. The El Niño event is characterized by low SSHA in the northern hemisphere, along the equator and along the eastern boundary, while high SSHA in the southwestern part of the basin. The IOD event shows a dipole like pattern with low SSHA in the east and high SSHA in the west. When the IOD co-occurred with El Niño, a distinct dipole pattern is clearly observed.
An Updated Water Masses Stratification of Indonesian Maritime Continent (IMC) Attributed to Normal and ENSO Conditions by Argo Float Bahiyah, Amirotul; Wirasatriya, Anindya; Mardiansyah, Wijaya; Iskandar, Iskhaq
Science and Technology Indonesia Vol. 9 No. 2 (2024): April
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26554/sti.2024.9.2.299-313

Abstract

The tropical area of the Indonesian Maritime Continent (IMC) is frequently regulated by El Niño Southern Oscillation (ENSO), resulting in various water mass stratification in every climate event, such as El Niño and La Niña occurrences. As a consequence, changes in the typical Indonesian Throughflow (ITF) are linked to ENSO circumstances that affect the Indian Ocean. This study used Argo float data to evaluate the change in water mass stratification and vertical density profiles along the main pathway of ITF at each event. However, due to a scarcity of observation data, the comparison study of normal to ENSO occurrences has been limited in the ITF area. In typical circumstances throughout the year, the entrance channel (the western Pacific Ocean, the northern waters of Molucca Island, and the Halmahera Sea) had a higher saline value and cooler water masses than other ITF channels, with a range of roughly 33.5 - 35.5 PSU/13 - 22 ◦C, particularly during the Northwest (NW) Monsoon (December to February or DJF). Unlike the inlet, the Temperature-Salinity (T-S) diagram showed a declining value in both parameters (Celebes Sea, Makassar Strait, and Molucca Sea). Still, the outflow pathway in the Southeastern Tropical Indian Ocean (SETIO) showed a rising T-S diagram. During La Niña events, IMC water masses are often portrayed as fresher and warmer, while reverse circumstances are depicted in El Niño events with exclusion at SETIO station, indicating saltier and colder water masses than normal conditions. An extreme alteration with a large T-S range is mostly depicted in Makassar Strait from Southeast (SE) monsoon (September to November or SON) to NW monsoon, followed by the Banda Sea and then the Molucca Sea.
Annual and Interannual Rainfall Variability in Indonesia Using Empirical Orthogonal Function (EOF) Analysis and Its Response to Ocean-Atmosphere Dynamics Ariska, Melly; Suhadi, Suhadi; Supari, Supari; Irfan, Muhammad; Iskandar, Iskhaq
Jurnal Ilmu Fisika Vol 16 No 2 (2024): September 2024
Publisher : Jurusan Fisika FMIPA Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jif.16.2.151-165.2024

Abstract

We investigate rainfall variability in Indonesia using the Empirical Orthogonal Function (EOF) method. The analysis starts by taking three main modes of EOF results, namely EOF1, EOF2, and EOF3. The EOF1 region is southern Indonesia, from southern Sumatra to Timor Island, parts of Kalimantan, parts of Sulawesi, and parts of Irian Jaya. The EOF2 region is located in northwestern Indonesia and includes the northern part of Sumatra and the northwestern part of Kalimantan. The EOF3 region covers Maluku. This study aims to analyze the annual and inter-annual variability of rainfall in anticipation of the threat of hydrometeorological disasters. Based on the correlation value of the principal component (PC) with the dipole mode index (DMI) and Niño3.4 index, it has a period similar to El Niño-Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD). Rainfall in Indonesia is very sensitive to sea surface temperature (SST) in the southeastern Indian Ocean and the central Pacific Ocean, which means that rainfall patterns in Indonesia can change significantly if SST in the region changes.
Power Sector Under Climate Scenario: A Study of Climate Policy Impact on Indonesia Electricity System Kurniawan, Hendra; Iskandar, Iskhaq; Sidik, Muhammad Abu Bakar
Indonesian Journal of Environmental Management and Sustainability Vol. 8 No. 2 (2024): June
Publisher : Magister Program of Material Science, Graduate School of Universitas Sriwijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26554/ijems.2024.8.2.50-62

Abstract

In the sixth assessment report, the IPCC indicates that global temperature increased by 1.11 (±0.13) degrees Celsius in 2019 due to 6.5 gigatons of CO2eq of greenhouse gas emissions into the atmosphere. The power sector is a major global greenhouse gas emitter, particularly in Indonesia. Indonesia’s electricity sector emitted 149.90 million tons of CO2eq greenhouse gas in 2020, which is expected to increase to 158.30 million tons of CO2eq in 2021. Indonesia has committed to reducing greenhouse gas emissions according to the Paris Agreement. The Paris Agreement has been ratified into national law, accommodating Indonesia’s roadmap to net zero by 2060. The emissions reduction target was published in 2022 through the enhanced Nationally Determined Contribution (NDC). This study aims to analyze the impact of climate policy in Indonesia’s electricity sector to meet the net zero emissions target by 2060. Projection and calculation in this study were conducted using the Low Emissions Analysis Platform (LEAP). Data from 2020, including electricity demand, existing capacity, energy production, energy intensity, lifetime, and capacity factor, were used to support LEAP analysis. The data were obtained from the PLN statistical book, PLN sustainability report, Indonesia’s statistical book, and climate change mitigation and adaptation reports in Indonesia. This study developed three climate scenarios, including business as usual (BAU), sustainable development (SD), and low-carbon development (LCD). These scenarios draw upon current climate policies that have various impacts on electricity generation in Indonesia. Based on LEAP analysis, by 2060, energy demand is expected to increase to 300.36 MTOE (BAU), 200.93 MTOE (SD), and 76.97 MTOE (LCD). Consequently, each climate scenario requires an increase in installed capacity to 821.82 GW (BAU), 727.06 GW (SD), and 334.58 GW (LCD). The renewable energy mix is projected to be 21% (BAU), 69% (SD), and 100% (LCD). Each scenario requires investment to develop capacity to meet energy demand. The investment cost is estimated to be 1,671.58 million USD (BAU), 1,537.64 million USD (SD), and 816.51 million USD (LCD). GHG emissions are projected to rise to 1,746.31 million tons of CO2eq (BAU) and 264.39 million tons of CO2eq (SD). However, the LCD scenario expects to achieve net zero emissions by 2060.
ANALISIS CURAH HUJAN EKSTREM DI KEPULAUAN MALUKU DAN HUBUNGANNYA DENGAN FENOMENA ENSO Khofaria, Hafizhu; Iskandar, Iskhaq; Suhadi
Jurnal Ilmu Fisika dan Pembelajarannya (JIFP) Vol 8 No 2 (2024): Jurnal Ilmu Fisika dan Pembelajarannya (JIFP)
Publisher : Program Studi Pendidikan Fisika, UIN Raden Fatah Palembang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.19109/m541nx19

Abstract

Global climate anomalies can cause extreme climates, especially in Indonesia, one of which includes extreme rainfall events. Rainfall in Indonesia itself is coherent and correlated with ENSO variations in the Pacific Ocean. Apart from the influence of ENSO, there are other influences such as regional, local factors and regional topography which also greatly determine the characteristics of rainfall, especially in the Maluku Islands which have different rainfall patterns from other areas in Indonesia. The complex phenomena that influence rainfall in the Maluku region attract the attention of researchers to analyze extreme rainfall patterns and their relationship to ENSO relationships. This research uses daily rainfall data at BMKG and Metomanz stations from 1992 to 2022 for 30 years, and uses a simple linear regression method obtained from the results of ERA 5 reanalysis data with BMKG data, at stations that do not have complete data for 30 years. This research was conducted using the Mann-Kendall and Sen's Slope methods. The Mann-Kendall method is used to determine the degree of significance and change in positive or negative direction. Meanwhile, the Sen's Slope Method is used to determine the magnitude of the linear slope of the resulting trend. Extreme climate patterns in the Maluku Islands are influenced by the ENSO phenomenon and geographical conditions of the region. There are significant trend changes in CDD, CWD, and PRCPTOT. The Rnmm index is divided into three index limits (R20mm, R15mm, and R10mm).  Increasing trends of CDD, CWD, PRCPTOT, occurred sequentially at Mathilda Batlayeri, Kuffar, Bandaneira stations. The Rnmm index is divided into three index limits R20mm, R15mm, and R10mm and there is a sequential increasing trend at Bandaneira, Namlea and Mathilda Batlayeri stations
Exploration of Seasonal Dynamics of Tropical Indo-Pacific Ocean during Dry, Wet and Neutral Years in Indonesia using Composite Method Ariska, Melly; Suhanda, Alfin; Suhadi, Suhadi; Supari, Supari; Irfan, Muhammad; Iskandar, Iskhaq
Jurnal Penelitian Fisika dan Aplikasinya (JPFA) Vol. 14 No. 1 (2024)
Publisher : Universitas Negeri Surabaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26740/jpfa.v14n1.p67-83

Abstract

Applying rainfall data for each month from Princeton University from January 1948 to December 2016, the impact of the Pacific El Niño-Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD), which is focused in the Indian Ocean, on rainfall in Indonesia was examined. IOD occurrences are significantly correlated with rainfall, as seen by the simultaneous association of seasonal rainfall anomalies during the peak of the rainy season (NDJ) in Indonesia's dry, wet, and neutral years, as well as other climatic indices in both climates. Rainfall has occurred in parts of South Sumatra, Java, South Kalimantan, Nusa Tenggara, Sulawesi, and East Papua. Meanwhile, ENSO events significantly correlate with rainfall in the southern regions of Sumatra, Java, Kalimantan, Sulawesi, and Papua. El Niño is associated with low sea surface temperature anomalies in the Indonesian Sea and southeast Indian Ocean. The low SST anomaly lowers the mean sea surface level (MSL). It reduces the amount of water vapor in the atmosphere, suppressing atmospheric convection in Indonesia and leading to a very sharp decrease in rainfall. Based on the forecasting and exploration of rainfall patterns in Indonesia described in this study, this research can be used as a reference for the government to prepare preventive measures against extreme global climate change events and to predict hydrometeorological disasters in disaster-prone areas.
Variability of Temperature Extreme Observes in Kalimantan Jamiatul Khairunnisa Putri; Suhadi; Muhammad Irfan; Hamdi Akhsan; Iskhaq Iskandar
Jurnal Penelitian Pendidikan IPA Vol 10 No 11 (2024): November
Publisher : Postgraduate, University of Mataram

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29303/jppipa.v10i11.9048

Abstract

This study aims to analyze the trend of extreme temperatures in Kalimantan over the past few decades. The data used are daily temperatures from meteorological stations in West Kalimantan, Central Kalimantan, and South Kalimantan, with an observation period of January 1985 to December 2022. The research methodology involves four main stages: data collection, extreme temperature index calculation, trend detection, and correlation analysis with ENSO and IOD. The results showed an increasing trend in extreme temperatures (warming). The increase in mean annual maximum temperature (TXmean) ranged from 0.03°C to 2°C per century, while the mean annual minimum temperature increased from 0.2°C to 0.5°C per century. Monthly maximum value of daily max temperature (TXx) the increasing trend ranged from 0.19°C to 1.7°C, monthly maximum value of daily min temperature (TNx) increased from 0.1°C to 0.5°C. The monthly mean difference between daily max and min temperature (DTR) also shows an increase of 0.5°C to 1.7°C. This trend indicates that daytime (TXmean, TXx) and nighttime (TNmean, TNx) conditions in Kalimantan, especially in West, Central, and South Kalimantan, are getting hotter, with the daytime experiencing a more significant increase in temperature. The correlation between the extreme temperature index and ENSO and IOD is negative and positive, indicating that ENSO and IOD do not fully influence the increase in extreme temperatures. These findings have important implications for disaster mitigation planning and adaptation to climate change in the Kalimantan region.
Profile of Rainfall Patterns and Extreme Air Temperatures 1981-2020 in the Mosunal Region of Indonesia (Case Study: South Sumatra) Ariska, Melly; Supari, Supari; Irfan, Muhammad; Iskandar, Iskhaq
Jurnal Fisika Flux: Jurnal Ilmiah Fisika FMIPA Universitas Lambung Mangkurat Vol 21, No 1 (2024): Jurnal Fisika Flux: Jurnal Ilmiah Fisika FMIPA Universitas Lambung Mangkurat
Publisher : Lambung Mangkurat University Press

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20527/flux.v21i1.14022

Abstract

Increasing concentrations of greenhouse gases have led to changes in extreme climate events. This study aims to describe the picture of climate change in the South Sumatra Region during the last 40 years, namely from 1981-2020. Rainfall and extreme temperature data were obtained from BMKG data for South Sumatra Province at the Palembang City Climatology Station (SK Palembang City) and the Sultan Mahmud Badaruddin II Meteorological Station (SM SMB II). Maximum temperature data, minimum temperature and rainfall were obtained based on parameter profiles obtained from BMKG data for South Sumatra Province based on the ETCCDMI provisions. Maximum temperature data, minimum temperature and rainfall are processed with RClimDex software so that temperature and extreme rain index data are obtained. These indices are extreme climate indices consisting of TN90p, TX90p, TNn, TNx,TXx, TXx, TMAXmean, TMINmean, RX1day, RX5day, SDII, CDD and CWD. The results of this study indicate that the trend of air temperature will increase significantly in South Sumatra Province, especially the minimum air temperature, then the precipitation pattern will also increase, especially the accumulation of rainfall for 5 consecutive days. There is an increase in the number of dry days and a decrease in the number of wet days, as well as the higher accumulation of daily rainfall but the wet days are decreasing day by day. This is also increasingly having an impact on climate change in South Sumatra Province which is getting hotter day by day and the smoke disaster due to land and peat fires in South Sumatra Province is increasingly worrying.
Pengabdian Terintegrasi Dengan Mata Kuliah Eksplorasi Sumberdaya Laut Dan Estuari : Upaya Peningkatan Kesadaran Nelayan Terhadap Biota Yang Dilindungi Di Desa Sungsang Kabupaten Banyuasin Sumatera Selatan Fauziyah; Agustriani, Fitri; Nurjuliasti Ningsih, Ellis; Iskandar, Iskhaq; Yustian, Indra
Kemas Journal : Jurnal Pengabdian Masyarakat Vol. 2 No. 1 (2024): Kemas Journal - Januari - Juni
Publisher : Universitas PGRI Palembang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31851/kemas.v2i1.15020

Abstract

Pengabdian terintegrasi dengan mata kuliah adalah upaya Universitas Sriwijaya untuk mengkolaborasi kegiatan pengabdian dengan mata kuliah yang relevan, agar tercipta harmonisasi antara kegiatan akademik dan pengabdian serta aplikasinya di masyarakat. Salah satu materi penting Mata kuliah Eksplorasi Sumberdaya Laut dan Estuari (ELSE) adalah pada usaha perikanan tangkap berpotensi tertangkapnya spesies yang dilindungi, salah satunya dolphin dan belangkas yang ada di wilayah periaran Banyuasin- Sumatera Selatan. Kegiatan ini bertujuan untuk meningkat kesadaran nelayan di Desa Sungsang dalam menjaga biota laut yang dilindungi yang ada di wilayahnya. Kegiatan dilaksanakan pada bulan Agustus-September 2023 di laboratorium ESAK Jurusan Ilmu kelautan Universitas Sriwijaya dan Desa Sungsang I, Kabupaten Banyuasin, Sumatera Selatan. Metode yang dilakukan adalah wawancara dan edukasi kepada nelayan. Mahasiswa didampingi asisten belajar membuat kuisioner saat praktikum mata kuliah ELSE di laboratorium dan mengaplikasikan hasil kuisioner kepada responden (Nelayan) di Desa Sungsang I. Metode Pre dan post test digunakan sebagai instrument evaluasi kegiatan pengabdian. Hasil yang diperoleh adalah terjadi peningkatan pemahaman nelayan dalam mengidentifikasi biota yang dilindungi yaitu belangkas dan dolphin (dari 88% menjadi 100%), dapat membedakan jenis kelamin biota (dari 60% menjadi 100%), terjadi peningkatan kesadaran nelayan bahwa dolphin dan belangkas adalah biota yang dilindungi (dari 60% menjadi 100%), terjadi peningkatan kesadaran nelayan untuk melepaskan dolphin dan belangkas yang terjerat jaring ke perairan (dari 60% menjadi 100%) dan membiarkan biota tersebut jika melewati kapal. Manfaat ganda dari kegiatan pengabdian terintegrasi ini adalah nelayan mendapatkan ilmu pengetahuan untuk melestarikan biota yang dilindungi dan mahasiswa dapat menerapkan ilmu yang didapat secara langsung di lapangan.
COMMUNITY-BASED MANGROVE FORESTS CONSERVATION FOR SUSTAINABLE FISHERIES Eddy, Syaiful; Ridho, Mohammad Rasyid; Iskandar, Iskhaq; Mulyana, Andy
Jurnal Silvikultur Tropika Vol 7 No 3 (2016): Jurnal Silvikultur Tropika (Suplemen Desember)
Publisher : Departemen Silvikultur, Fakultas Kehutanan dan Lingkungan, Institut Pertanian Bogor (IPB)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29244/j-siltrop.7.3.S42-S47

Abstract

The mangrove forests are a type of salt tolerant vegetation, living in tidal zones in tropical and subtropical coastalareas with unique ecosystem that have a strategic function as a connector and counterweight of terrestrial and marineecosystems. Mangrove forests are a productive ecosystem and they have complex functions, such as physical functions,biological functions and socio-economic functions. Fishery resources of mangrove forests are very productive, bothquantitatively and qualitatively, because the mangrove forests act as the natural habitat (spawning, nursery and feedinggrounds) for various species of fish, shrimps and crabs, as well as a source of germplasm and genetic pool. Mangroveforests also provide valuable ecosystem services to coastal communities, tourist attractions, nature conservation,education and research. However, these ecosystems are fragile because it is very sensitive to environmental changes,usually because anthropogenic influences; therefore, it is difficult to be restored. In addition, these ecosystems are soopenly accessible that easily exploited by humans; this can reduce its quality and quantity. Local communities who usemangrove forests and their resources may have considerable botanical and ecological knowledge about their forests.Silvofishery techniques in aquaculture are very suitable for community-based mangrove forests conservation efforts.Silvofishery is an integrated model that considers both economically benefit and conservation.Key words: mangrove conservation, sustainable fisheries, community-based