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All Journal Jurnal Silvikultur Tropika (JST) Jurnal Ilmu dan Teknologi Kelautan Tropis Indonesian Journal of Geography JOURNAL OF COASTAL DEVELOPMENT Jurnal Penelitian Fisika dan Aplikasinya (JPFA) Jurnal Matematika & Sains Journal of Mathematical and Fundamental Sciences International Journal of Advances in Intelligent Informatics JURNAL ILMIAH PENDIDIKAN FISIKA AL BIRUNI Jurnal Fisika FLUX Science and Technology Indonesia Jurnal Penelitian Sains Jurnal Penelitian Pendidikan IPA (JPPIPA) IJEMS (Indonesian Journal of Environmental Management and Sustainability) Marine Research in Indonesia Jurnal Kelautan Nasional Jurnal Ilmu Fisika International Journal of Remote Sensing and Earth Sciences (IJReSES) Jurnal Teori dan Aplikasi Fisika Indobiosains SRIWIJAYA JOURNAL OF ENVIRONMENT JIFP (Jurnal Ilmu Fisika dan Pembelajarannya) Makara Journal of Science Kemas Journal:Jurnal Pengabdian masyarakat

Iskhaq Iskandar

University Of Sriwijaya

Author-ID : 289165

Agriculture, Biological Sciences & Forestry Astronomy Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Chemistry Civil Engineering, Building, Construction & Architecture Computer Science & IT Decision Sciences, Operations Research & Management Earth & Planetary Sciences Economics, Econometrics & Finance Education Electrical & Electronics Engineering Energy Engineering Environmental Science Immunology & microbiology Law, Crime, Criminology & Criminal Justice Library & Information Science Materials Science & Nanotechnology Mathematics Physics Public Health Social Sciences Transportation

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Dynamical Link of Peat Fires in South Sumatra and the Climate Modes in the Indo-Pacific Region Raden Putra; Deni Okta Lestari; Edy Sutriyono; Sabaruddin Sabaruddin; Iskhaq Iskandar
Indonesian Journal of Geography Vol 51, No 1 (2019): Indonesian Journal of Geography
Publisher : Faculty of Geography, Universitas Gadjah Mada

Peat fire is one of the environmental disasters occurring widespread during the dry season in South Sumatra. The region has long been recognized to have extensive peatland, hence it is considered as the vulnerable areas to fire. This study employs spatial analysis to evaluate the likely linked factors causing peat fire in the study area. Two interannual climate modes such as the El Niño – Southern Oscillation and Indian Ocean Dipole were considered to have affected the area with respect to climate anomaly at the 1995-2016 periods. This phenomenon was followed by the peat fire in many areas. There appears a close linkage between the occurrence of peat fires and climate anomaly. A number of hotspots tend to occur annually during the drought season. A significant number of hotspots took place during the 2006 pIOD and 2015 El Niño events due to a significant decrease in rainfall intensities.

INTRASEASONAL VARIATIONS OF NEAR-SURFACE ZONAL CURRENT OBSERVED IN THE SOUTH-EASTERN EQUATORIAL INDIAN OCEAN Iskhaq Iskandar
JOURNAL OF COASTAL DEVELOPMENT Vol 15, No 1 (2011): Volume 15, Number 1, Year 2011
Publisher : JOURNAL OF COASTAL DEVELOPMENT

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (425.174 KB)

Dynamics of intraseasonal variability in the near-surface zonal currents in the southeastern equatorial Indian Ocean is examined through the analysis of the observed currents at 1.5S, 90E and sea surface height (SSH) as well as wind fields along the equator for the period of 23 October 2001 to 3 July 2007. The result demonstrates that the zonal current has energetic intraseasonal variations within the period band of 30–70 days. These oceanic intraseasonal variations are forced by the atmospheric intrasea-sonal disturbances from the west to the central Indian Ocean basin west of the mooring location. The coherence analysis indicates that these intraseasonal zonal currents are coherent with the intraseasonal SSH along the equatorial Indian Ocean. The coherence and lag-correlation analyses agree that these intraseasonal zonal currents are associated with eastward propagating waves with a phase speed falls in the first two vertical modes of baroclinic waves observed in the equatorial Indian Ocean.

On the Influence of Enso And IOD on Rainfall Variability Over The Musi Basin, South Sumatra Wijaya Mardiansyah; Dedi Setiabudidaya; M. Yusup Nur Khakim; Indra Yustian; Zulkifli Dahlan; Iskhaq Iskandar
Science and Technology Indonesia Vol. 3 No. 4 (2018): October
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

The southern Sumatera region experiences one rainy season and one dry season in a year associated with seasonal change in monsoonal winds. The peak of rainy season is occurring in November-December-January during the northwest monsoon season, while the dry season comes in June-July-August during the southeast monsoon season. This study is designed to evaluate possible influence of the coupled ocean-atmospheric modes in the tropical Indo-Pacific region, namely the El Niño-Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD) on the rainfall variability over the catchment area of the Music Basin, South Sumatera. The ENSO and IOD occurrences were reflected by the variability of sea surface temperature (SST) in the tropical Pacific and Indian Ocean, respectively. During El Niño and/or positive IOD episode, negative SST anomalies cover the eastern tropical Indian Ocean and western tropical Pacific including the Indonesian seas, leading to suppress convective activities that result in reduce precipitation over the maritime continent. The situation is reversed during La Niña and/or negative IOD event. The results revealed that the high topography area (e.g. Bukit Barisan) was shown to be instrumental to the pattern of rainfall variability. During the 2010 negative IOD co-occurring with La Niña event, the rainfall was significantly increase over the region. This excess rainfall was associated with warm SST anomaly over the eastern tropical Indian Ocean and the Indonesian seas. On the other hand, extreme drought event tends to occur during the 2015 positive IOD simultaneously with the occurrence of the El Niño events Investigation on the SST patterns revealed that cold SST anomalies covered the Indonesian seas during the peak phase of the 2015 positive IOD and El Niño event.

Observed Intraseasonal Oceanic Variations in the Eastern Equatorial Indian Ocean and in the Outflow Straits of the Indonesian Throughflow Iskhaq Iskandar; Yukio Masumoto; Keisuke Mizuno
Journal of Mathematical and Fundamental Sciences Vol. 42 No. 2 (2010)
Publisher : Institute for Research and Community Services (LPPM) ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/itbj.sci.2010.42.2.3

The observed currents in the eastern equatorial Indian Ocean and in the outflow straits of the Indonesian Throughflow (ITF) are shown to have significant intraseasonal variations and coherency during January 2004 "“ November 2006. The wavelet analysis between the eastern equatorial Indian Ocean and the ITF straits demonstrates significant intraseasonal coherency for the observed current at 50m depth. At 150m depth, the intraseasonal coherency only occurs between the observed currents in the eastern equatorial Indian Ocean and in the Lombok and Ombai Straits. On the other hand, at 350m depth the intraseasonal coherency is only found between the eastern equatorial Indian Ocean and the Ombai Strait. This intraseasonal coherency is associated with the wind-forced equatorial Kelvin waves which propagate eastward along the equatorial and coastal wave guides. Near-surface intraseasonal variations are associated with the first baroclinic mode with typical phase speed of 2.91 ± 0.46 m s-1, while the deeper layer intraseasonal variations are associated with the second baroclinic mode with typical phase speed of 1.59 ± 0.18 m s-1. Moreover, the lag correlations between the zonal winds and the observed currents at the ITF straits further demonstrate the source of intraseasonal variations in the ITF.

The Role of Equatorial Oceanic Waves in the Activation of the 2006 Indian Ocean Dipole Iskhaq Iskandar
Journal of Mathematical and Fundamental Sciences Vol. 44 No. 2 (2012)
Publisher : Institute for Research and Community Services (LPPM) ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/itbj.sci.2012.44.2.2

Observations and a linear wave model were used to evaluate the role of equatorial oceanic wave processes in affecting the evolution of the 2006 positive Indian Ocean Dipole (IOD), focusing on the activation phase of the event. The observations indicate the presence of upwelling equatorial waves and westward near-surface zonal currents along the equator during the activation phase of the event in August 2006. These upwelling equatorial waves (negative sea surface height anomalies) and westward zonal current anomalies contributed to significant sea surface cooling in the eastern equatorial Indian Ocean. The model results reveal that the upwelling equatorial waves and westward nearsurface zonal currents were mainly generated by wind-forced Kelvin waves associated with the easterly wind anomalies. On the other hand, anomalous easterly winds along the equator during June caused downwelling waves (positive sea surface height anomalies) in the off-equatorial region which propagated westward and elevated sea levels in the western region. The model further shows that a complex interplay of wind-forced and boundary-generated Rossby waves elevated sea levels in the western equatorial Indian Ocean during the activations phase of the 2006 IOD event.

Simulated Interannual Modulation of Intraseasonal Kelvin Waves in the Equatorial Indian Ocean Iskhaq Iskandar; Dedi Setiabudidaya; Wijaya Mardiansyah; Muhammad Irfan
Journal of Mathematical and Fundamental Sciences Vol. 48 No. 3 (2016)
Publisher : Institute for Research and Community Services (LPPM) ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.math.fund.sci.2016.48.3.3

Outputs from a high-resolution ocean general circulation model (OGCM) for the period of 1990-2003 indicate an interannual modulation of intraseasonal Kelvin waves along the equatorial Indian Ocean. During normal conditions without IOD event, the first mode explains about 30-40% of the total variance in the western (60-65ºE) and central (75-80ºE) basin, while the second mode contributes up to 45% to the total variance in the central basin around the longitude of 82ºE. In contrast, during the 1997/98 IOD event, the fourth mode caused about 40% of the total variance in the central and eastern basin. During the 1994 IOD event, the contribution from the fourth baroclinic mode in the eastern basin caused 45% of the total variance. In the central basin, the second and the fourth baroclinic mode caused almost the same variance (~40%). The variations in the characteristics of the intraseasonal Kelvin waves are related to variations in the vertical stratification. During the IOD event, the pycnocline in the eastern basin was raised by about 50 m and the stratification at the upper level is strengthened, while it is weakened at lower levels. These changes lead to an increase in the contribution of higher-order baroclinic modes.

Respective Influences of Indian Ocean Dipole and El NiÃ±o-Southern Oscillation on Indonesian Precipitation Deni Okta Lestari; Edy Sutriyono; Sabaruddin Sabaruddin; Iskhaq Iskandar
Journal of Mathematical and Fundamental Sciences Vol. 50 No. 3 (2018)
Publisher : Institute for Research and Community Services (LPPM) ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.math.fund.sci.2018.50.3.3

The respective influences of the Indian Ocean Dipole (IOD) and El NiÃ±o-Southern Oscillation (ENSO) on Indonesian precipitation were evaluated using monthly precipitation data from the Global Precipitation Climatology Centre (GPCC) for January 1948 to December 2013. Simultaneous correlation between seasonal precipitation anomalies and climate indices for these two types of climate modes revealed that IOD events have a significant correlation with the precipitation over southern Sumatra, Java, southern Kalimantan, the Nusa Tenggara Islands, some parts of Sulawesi and eastern Papua. Meanwhile, ENSO events have a significant correlation with the precipitation over southern Sumatra, Java, Kalimantan, Sulawesi, and Papua. Droughts during the dry season (JJA and SON) typically occur when a positive IOD event simultaneously occurs with an El NiÃ±o event associated with anomalous low SST observed in the Indonesian seas and the southeastern equatorial Indian Ocean. Low SST anomalies lead to low-level wind divergence and reduce water vapor in the lower atmosphere, supress atmospheric convection over the Indonesian region and then cause a decrease in precipitation.

RESTORASI HUTAN MANGROVE TERDEGRADASI BERBASIS MASYARAKAT LOKAL Syaiful Eddy; Iskhaq Iskhaq Iskandar; Moh. Rasyid Ridho; Andy Mulyana
Indobiosains 2019: Volume 1 No 1 Februari 2019
Publisher : Universitas PGRI Palembang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31851/indobiosains.v1i1.2298

Mangrove forests are the main ecosystem of life support in coastal areas that have important ecological functions.Although the mangrove forests have many important functions in the coastal areas but excessive used and not oriented to sustainabilitycause degradation of mangrove forest ecosystems. The main cause of mangrove forests degradation in the world is due to anthropogenic influences such as agricultural activities, plantations, fish and shrimp ponds, settlements, loggings (legal logging and illegal logging), pollution, mining and salt ponds. Therefore, local community participation is needed tocontrolthe utilization of mangrove forests. In addition, local people living in coastal areas are at the forefront in mangrove forests restoration because they require the existence of sustainable mangrove forest and have local wisdom that has been tested. Ecological functions and economic functions of mangrove forest ecosystems can be maintained through increasing public awareness of the importance of preservation, in order to reach the optimization and sustainability of the mangrove forests. The local communityparticipation should be supported by government, NGOs and researchers/academics.Hutan mangrove merupakan ekosistem utama pendukung kehidupan di wilayah pesisir yang memiliki fungsiekologisyang penting. Walaupun hutan mangrove memiliki banyak fungsi penting di wilayah pesisir namun sering kali pemanfaatan yang berlebihan dan tidak berorientasi pada keberlanjutan telah menyebabkan degradasi terhadap ekosistem hutan mangrove. Penyebab utama degradasi hutan mangrove di dunia adalah akibat pengaruh antropogenik berupa aktivitas pertanian, perkebunan, tambak ikan dan udang, pembangunan pemukiman, penebangan kayu (legal logging dan illegal logging), pencemaran, pertambangan dan tambak garam.Oleh karena itu peran serta masyarakat lokal sangat diperlukan dalam upaya mengontrol laju penggunaan hutan mangrove. Disamping itu, masyarakat lokal yang hidup di wilayah pesisir merupakan ujung tombak dalam merestorasi kawasan hutan mangrove karena mereka membutuhkan keberadaan hutan mangrove yang lestari serta memiliki kearifan lokal yang telah teruji. Fungsi ekologis dan ekonomis ekosistem hutan mangrove dapat dipelihara melalui peningkatan kesadaran masyarakat akan pentingnya pelestarian, sehingga tercapai optimalisasi dan keberlanjutan pengelolaan kawasan tersebut. Peran masyarakat tersebut harus pula didukung oleh peran pemerintah, LSM dan peneliti/akademisi.

INDENTIFYING PATTERNS OF SATTELITE IMAGERY USING AN ARTIFICIAL NEURAL NETWORK Iskhaq Iskandar; Azhar Affandi; Dedi Setiabudidaya; Muhammad Irfan; Wijaya Mardiansyah; Fadli Syamsuddin
International Journal of Remote Sensing and Earth Sciences (IJReSES) Vol 9, No 1 (2012)
Publisher : National Institute of Aeronautics and Space of Indonesia (LAPAN)

An artificial neural network analysis based on the self-organizing map (SOM) was used to examine patterns of satellite imagery. This study used 3 × 4 SOM array to extract patterns of satellite-observed chlorophyll-a (chl-a) along the southern coast of the Lesser Sunda Islands from 1998 to 2006. The analyses indicated two characteristic spatial patterns, namely the northwest and the southeast monsoon patterns. The northwest monsoon pattern was characterized by a low chl-a concentration. In contrast, the southeast monsoon pattern was indicated by a high chl-a distributed along the southern coast of the Lesser Sunda Islands. Furthermore, this study demonstrated that the seasonal variations of those two patterns were related to the variations of winds and sea surface temperature (SST). The winds were predominantly southeasterly (northwesterly) during southeast (northwest) monsoon, drived offshore (onshore) Ekman transport and produced upwelling (downwelling) along the southern coasts of the Lesser Sunda Islands. Consequently, upwelling reduce dSST and helped replenish the surface water nutrients, thus supporting high chl-a concentration. Finally, this study demonstrated that the SOM method was very useful for the identifications of patterns in various satellite imageries.

TREND IN PRECIPITATION OVER SUMATERA UNDER THE WARMING EARTH Iskhaq Iskandar; Muhammad Irfan; Fadli Syamsuddin; Akmal Johan; Pradanto Poerwono
International Journal of Remote Sensing and Earth Sciences (IJReSES) Vol 8, (2011)
Publisher : National Institute of Aeronautics and Space of Indonesia (LAPAN)

A long-term climate variations in the western Indonesian region (e.g. Sumatera) were evaluated using precipitation data as a proxy. The result showed that there was a long-term climate variation over Sumatera region indicated by a decreasing trend in precipitation (drying trend). Moreover, the long-term precipitation trend has a strong seasonality. Remarkable decreasing trend at a rate of 3.9 cm/year (the largest trend) was observed during the northwest monsoon (DJF) season, while the smallest decreasing trend of 1.5 cm/year occurred during the southeast monsoon (JJA) season. This result suggested that the Sumatera Island experienced a drying trend during the northwest monsoon season, and a dryer condition will be more frequently observed during the southeast monsoon season. The long-term precipitation over the Sumatera Island was linked to coupled air-sea interactions in the Indian and Pacific oceans. The connection between the seasonal climate trends and sea surface temperature (SST) in the Indian and Pacific oceans was demonstrated by the simultaneous correlations between the climate indices (e.g. Dipole Mode Index (DMI) and the Niño3.4 index) and the precipitation over the Sumatera Island. The results suggested that both the Indian Ocean Dipole (IOD) and the El Niño-Southern Oscillation Index (ENSO) have significant correlation with precipitation. However, remarkable correlations were observed during the fall transition of the IOD event. Keywords: Climate variations, Dry season, Precipitation, Sumatera and Kalimantan, Wet season.

Co-Authors AA Sudharmawan, AA Aan Johan Wahyudi Adam Darmawan Afdal Agus Dwi Saputra Akmal Johan Aldri Frinaldi ANDY MULYANA Anindya Wirasatriya Anna IS Purwiyanto Apriani, Yosi Arsali Arsali Assaidah, Assaidah Azhar Affandi Azhar Kholiq Affandi Bahiyah, Amirotul Dedi Setiabudidaya Deni Okta Lestari Dominikus Krisna Herlambang Dwi Setyawan Eddy, Syaiful Edy Sutriyono Edy Sutriyono FAUZIYAH Fitri Agustriani Hadi Hamdi Akhsan Hilda Zulkifli Hilda Zulkifli Indra Yustian Jamiatul Khairunnisa Putri Keisuke Mizuno Khairul Saleh Khakim, Mokhamad Yusup Nur Khofaria, Hafizhu Kusuma, Willy Anta Lestrai, Deni Okta Melly Ariska Moh. Rasyid Ridho Mokhamad Yusup Nur Khakim Muhammad Abu Bakar Sidik Muhammad Hendri Muhammad Irfan Muhammad Irfan Muhammad Nur Nuril Azhar Nurjuliasti Ningsih, Ellis Pradanto Poerwono Puad Maulana Mandailing Putriyani, Fena Siska Qurnia Wulan Sari Raden Putra Rendy M. Wahid Rezi Apri Rozirwan . Sabaruddin Kadir Sabaruddin Sabaruddin SABARUDDIN, . Septi Hermialingga Sofian, Ian Mochamad Suhadi Suhadi Suhadi Suhadi Suhanda, Alfin Supari Supari Supari Supari, Supari Wijaya Mardiansyah Wijaya Mardiansyah Wijaya Mardiansyah Wijaya Mardiansyah Wijaya Mardiansyah Wijaya Mardiansyah, Wijaya Yukio Masumoto Zulfikhar Zulfikhar Zulfikhar, Zulfikhar Zulkifli Dahlan

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