Papers by Jonson Lumban-Gaol
Jurnal Teknologi Perikanan dan Kelautan/Jurnal teknologi perikanan dan kelautan, Feb 1, 2024
Upwelling is the process of seawater mass rising from the lower layers to the surface due to surf... more Upwelling is the process of seawater mass rising from the lower layers to the surface due to surface pressure differences. The upwelling process will increase the fertility of the waters because the water mass in the deep layer rises to the surface which is rich in nutrients needed by phytoplankton to grow. The extent of the upwelling area (deformation radius) will determine the impact of the upwelling process in the waters. This research aims to analyze the upwelling process and deformation radius from thermal sensor satellite data. The data used were daily thermal satellite data and monthly averages during 2014-2018. Data from the Argo buoy was used to validate the satellite data and calculate the upwelling deformation radius. Statistical analyses such as correlation, Root Mean Square Error (RMSE), bias, and standard deviation were applied to test the accuracy of the satellite estimation of the Sea Surface Temperature (SST) data. Deformation radius calculation data from Argo showed that in the eastern season of upwelling, the SST ranged between 24 to 26ºC, otherwise normally it ranged between 27 to 29ºC. The correlation between SPL from satellite data and SPL data from Argo is 0.92, the RMSE value was 0.0236, the bias was 0.017, and the standard deviation was 0.287. The correlation coefficient between the deformation radius from in situ data and satellite data was calculated to be high (r=0.9), indicating that satellite imagery can be used to determine the deformation radius.
Satellite altimetry in Indonesian waters
Elsevier eBooks, 2023
International Journal of Remote Sensing and Earth Sciences (IJReSES), May 31, 2017
This study aimed to estimate the concentration of chlorophyll-a from satellite imagery of Nationa... more This study aimed to estimate the concentration of chlorophyll-a from satellite imagery of National Polar-Orbiting Operational Environmental Satellite System (NPOESS) Preparatory Project (NPP) in the south Java Sea waters and compare it to the concentrations of chlorophyll-a estimation result from the MODIS-Aqua satellite. NPP satellite had Visible/Infrared Imager Radiometer Suite (VIIRS) sensors which performance was same as Moderate Resolution Imaging Spectroradiometer (MODIS) sensor with a better spatial resolution. This study used daily satellite imagery of VIIRS-NPP for the period of September 2012 to August 2013. The algorithm that was used to estimate the concentration of chlorophyll-a was Ocean Color 3-band ratio (OC-3). The results showed that the spatial distribution pattern of chlorophyll-a concentration between VIIRS-NPP sensor and MODIS had the same pattern, but the estimation of chlorophyll-a concentration from the MODIS sensor was higher than VIIRS-NPP sensor. The concentration of chlorophyll-a showed that there were spatial and temporal variation in the south Java Sea waters. Generally, concentrations of chlorophyll-a was higher in East monsoon than West monsoon.
Journal of Marine and Aquatic Sciences
South Java Sea are regions that have quite complex dynamics because they are influenced by sever... more South Java Sea are regions that have quite complex dynamics because they are influenced by several factors, both regionally and globally. The influence certainly affects the variations in oceanographic features such as Sea Surface Temperature (SST), Sea Surface Height (SSH), and Chlorophyll-a concentration. Observation of oceanographic feature at this time has many methods, one of them by remote sensing. The purpose of this study is to calculate the variation of oceanographic conditions based on satellite data and its correlation with field data. The results show that the SPL and ATPL data with the field data have a fairly good relationship, where the value of R2 reaches 0.74 and 0.9. In general, the variation of oceanographic data has the same pattern that is changing seasonally. SST and SSH data are at their maximum in the January-March period, while the minimum is July-September. While the concentration of chlorophyll-a is at the maximum condition in July-September and minimum i...
International Journal of Remote Sensing and Earth Sciences (IJReSES), 2014
Coastal upwelling play an important role in biological productivity and the carbon cycle in the o... more Coastal upwelling play an important role in biological productivity and the carbon cycle in the ocean. This research aimed to examine the phenomenon of coastal upwelling that occur in the coastal waters north of Papua continent under the influence of Westerly Wind Burst(WWB) prior to the development of El Nino in the Pacific. Data consisted of sea surface temperature, vertical oceanic temperature, ocean color satellite image, wind stress and vector wind speed image, sea surface high, and Nino 3.4 index. Coastal upwelling events in the northern coastal waters of Papua continent occurred in response to westerly winds and westerly wind burst (WWBs) during December to March characterizing by low sea surface temperature (SST) (25 - 28C), negative sea surface high deviation and phytoplankton blooming, except during pre-development of the El Nino 2006/2007 where weak upwelling followed by positive sea surface high deviation. Strong coastal upwelling occurred during two WWBs in December an...
Seasonal coastal upwelling in the Bali Strait: a model study
IOP Conference Series: Earth and Environmental Science, 2021
Bali Strait is part of fisheries management zone (WPP 573), where abundant fishery potential, of ... more Bali Strait is part of fisheries management zone (WPP 573), where abundant fishery potential, of lemuru fish commodity. Here, physical oceanographic setting such as upwelling event plays an important role on maintaining high primary productivity and lemuru fish distribution. This study aims to describe physical process and dynamics of seasonal coastal upwelling using time-series datasets (2008 and 2014) of temperature, salinity, current velocity, surface chlorophyll-a (chl-a) from INDESO model and satellite imagery. The results showed that upwelling in the Bali Strait only during the southeast monsoon period when the south-easterly wind force surface Ekman drift of about 5.5 × 10−3 Sv flowing south-eastward (toward offshore). Upwelling event is characterized by minimum parameter of sea surface temperature (24.93 °C), and sea level anomaly (0.75 m), but maximum of surface chlorophyll-a (1.33 mg/m3). Furthermore, isotherm of 26 °C and Isohaline 33.7 psu are outcropped at sea surface i...
Remote Sensing Applications for Fishing Ground Assessment In Indonesian Waters
ABSTRAK Salah satu hal yang menarik untuk dikaji mengenai perairan Indonesia adalah dengan adanya... more ABSTRAK Salah satu hal yang menarik untuk dikaji mengenai perairan Indonesia adalah dengan adanya istilah yang mendunia yaitu Indonesian Through Flow atau yang dikenal dengan istilah Arus Lintas Indonesia (ARLINDO). Melalui pemahaman tentang oseanografi terutama oseanografi fisika maka dapat dipelajari kondisi fisik suatu wilayah perairan beserta karakteristik dari perairan tersebut. Saat ini parameter oseanografi fisika dapat dideteksi dengan menggunakan teknologi penginderaan jauh. Penelitian ini bertujuan untuk memantau dinamika massa air permukaan di Perairan Selat Makassar dengan menggunakan potensi dan pemanfaatan teknologi penginderaan jauh. Data yang digunakan dalam penelitian ini adalah data citra satelit Terra dan Aqua MODIS level 1 dengan resolusi 1 km dalam format Hierarchical Data Format (HDF). Data sebaran Suhu Permukaan Laut (SPL) adalah data harian selama dua tahun (2009-2010) dengan citra SPL untuk mendapatkan data time series. Data pendukung yang diambil menggunaka...
IOP Conference Series: Earth and Environmental Science, 2020
The Eastern Indian Ocean off Southern Java is one of the bigeye tuna fishing hotspots and has a f... more The Eastern Indian Ocean off Southern Java is one of the bigeye tuna fishing hotspots and has a fishing potential of 27%. Analyses of bigeye tuna fishing areas focus on the South Java-Bali waters at coordinates of 105°-120 ° E and 5 ° - 20 ° S. Oceanographic parameters affect the habitat of Bigeye tuna. Sub surface temperature is an important and major factor in fishing layers. Time series of sub surface temperature data from 2005-2017 was used as an input for the analysis of the fuzzy inference system method. This method has been widely used in fisheries areas but has not yet been applied to fishing ground predictions. The use of vertical temperature data variation such as 100 m, 150 m, 200 m, 250 m, and 300 m are expected to be able to map the most optimal fishing potential area for bigeye tuna fishing ground. The model output is verified using actual coordinate data to obtain a relationship between the model results and coordinate catch point. The result show that at 200 m is the...
ST-AGRID: A Spatio Temporal Grid Density Based Clustering and Its Application for determining the Potential Fishing Zones
This paper is aimed to propose a grid density clustering algorithm for spatio-temporal data that ... more This paper is aimed to propose a grid density clustering algorithm for spatio-temporal data that is based on the adaptation of the grid density based clustering algorithm. The algorithm is based on AGRID+ algorithm with 7 steps: partitioning, computing distance threshold, calculating densities, compensating densities, calculating density threshold (DT), clustering and removing noises. The adaptation is for the partitioning and calculating the distance threshold (r). The data utilized in this study is spatio-temporal fishery data located around the India Ocean from year 2000 until 2004. We utilized the fishery data in three types of aggregate , daily data, weekly data and monthy data. The result of this study shows that the time complexity for ST-AGRID is outperform the AGRID+. ST-AGRID improves the time complexity and at the same time maintains the accuracy. By utilizing the thresholding technique, clustering result of the ST-AGRID algorithm is identified as the potential fishing zone.
Jurnal Ilmu dan Teknologi Kelautan Tropis
Optimalisasi penangkapan ikan pelagis kecil di Laut Jawa masih dapat ditingkatkan dengan pengemba... more Optimalisasi penangkapan ikan pelagis kecil di Laut Jawa masih dapat ditingkatkan dengan pengembangan sistem informasi daerah penangkapan ikan. Penelitian ini bertujuan untuk memprediksi daerah penangkapan ikan pelagis kecil dengan menggunakan model Maximum Entropy (MaxEnt). Data yang digunakan dalam penelitian ini adalah data lingkungan berupa suhu permukaan laut (SPL) dan salinitas permukaan laut tahun 2018 di Laut Jawa yang diunduh dari Google Earth Engine melalui RStudio dan data posisi kapal penangkap ikan yang diunduh dari VIIRS Boat Detection (VBD). Model MaxEnt menunjukkan kinerja yang baik dengan nilai AUC 0,849. Kurva respons menunjukkan probabilitas tertinggi distribusi ikan berada pada SPL pada kisaran 27,0 – 31,0 oC, dan salinitas 32 – 34 psu. Peta prediksi daerah penangkapan ikan yang dihasilkan dengan pemodelan MaxEnt berupa peta kesesuaian habitat menunjukkan bahwa parameter salinitas berpengaruh sebesar 94,5% dan SPL sebesar 5,5%. Peta kesesuaian habitat ikan menunj...
Deteksi Mesoscale Eddies dari Satelit dan Hubungannya dengan Hasil Tangkapan Ikan Tuna Mata Besar (Thunnus obesus) di Perairan Selatan Jawa
Marine Science Department, Diponegoro University, Indonesia, Feb 1, 2010
El Niño Southern Oscillation (ENSO) Impact on Sea Surface Temperature (SST) derived from Satellite Imagery: A Preminary Study
Climate of the Past Discussions, 2014
Southeast Asian Seas (SEAS) span the largest archipelago in the global ocean and provide a comple... more Southeast Asian Seas (SEAS) span the largest archipelago in the global ocean and provide a complex oceanic pathway connecting the Pacific and Indian Oceans. The SEAS regional sea level trends are some of the highest observed in the modern satellite altimeter record that now spans almost two decades. Initial comparisons of global sea level reconstructions find that 17 year sea level trends over the past 60 years exhibit good agreement in areas and at times of strong signal to noise associated decadal variability forced by low frequency variations in Pacific trade winds. The SEAS region exhibits sea level trends that vary dramatically over the studied time period. This historical variation suggests that the strong regional sea level trends observed during the modern satellite altimeter record will abate as trade winds fluctuate on decadal and longer time scales. Furthermore, after removing the contribution of the Pacific Decadal Oscillation (PDO) to sea level trends in the past twenty...
The study is aimed at understanding the variability of sea surface height anomaly (SSHA) of Easte... more The study is aimed at understanding the variability of sea surface height anomaly (SSHA) of Eastern tropical Indian Ocean (E IO) and assessing its impact on bigeye tuna catchability. A nine-year (1993-2001) time series of SSHA data set are used in this investigation. A sixyear daily tuna fish catch data (1997-1999, and 2004-2006) and a eight-years (1993-2000) monthly average of tuna hook rate is derived from a tuna fishing company “Perikanan Samodra Besar” (PSB) Corp. Ltd. logbooks of 15-20 fishing vessels operated in E IO. Daily and an eight-year of monthly mean SSHA derived from data base of Colorado Center of Astrodynamics Research and NASA-POET-JPL respectively. The Spectrum analysis of SSHA and HR anomaly shows there are two dominant signals are representation of the annual and inter-annual variability. Significant interannual variability of SSHA is influenced El Nino Southern Oscillation (ENSO) and Indian Ocean Dipole mode (IOD). During ENSO and IOD event, SSHA negative in IOD...
Evidence of Spawning Migration of Protandrous Longtail Shad (Tenualosa Macrura) in the Siak River Estuarine, Indonesia
SSRN Electronic Journal
Analysis of Fishing with Led Lights in and around MPA and No Take Zones at Natuna Indonesia through VMS and VIIRS Data
2020 IEEE Asia-Pacific Conference on Geoscience, Electronics and Remote Sensing Technology (AGERS), 2020
Protected Areas (MPA) and No Take Zones are an effective tool for marine ecosystem preservation. ... more Protected Areas (MPA) and No Take Zones are an effective tool for marine ecosystem preservation. Indonesia requires fishing vessels larger than 30 gross tons to use a Vessel Monitoring System (VMS). Another way to detect fisheries is through Visible Infrared Radiometer Suite (VIIRS) data. To compare VMS and VIIRS data, an R package, “LLFI” (Led Light Fisheries Identifier) was created. This package provides several R-functions that can calculate the location of VMS using vessels at the overpass time of the VIIRS satellite. An MPA near the Natuna archipelago was chosen as the research area. VMS and VIIRS data for the entire year of 2018 were obtained for this Region of Interest. The R function “vms2viirs” calculated activity for small purse seine fisheries all through the ROI and for bouke ami fisheries in the southwestern part of the ROI. The R Function “vms2viirsanalysis” created three buffers around detected fishing vessels by the VIIRS satellite and linked the closest found vessels from the VMS dataset. The amount of identified vessels for Class C was significantly higher than those for class A and B. Approximately 10% of all detected led lights could be identified with a shipping number from the VMS data set. Only around 8% of identified vessels could be found inside MPA and around 3% could be found in a No Take Zone. Paths of identified vessels that some vessels did cross MPA's and No Take Zones. It can be concluded that the LLFI package is working successfully.
Pemetaan sumberdaya laut pulau nias pasca gempa bumi dengan teknologi inderaja satelit sebagai landasan kebijakan pengelolaan sumberdaya
Viabilitas konsentrasi klorofil-a di perairan utara Sumbawa berdasarkan data satelit SeaFiFS
... di perairan Sumbawa termasuk relatif tinggi dibandingkan dengan lokasi lain di Indonesia dan ... more ... di perairan Sumbawa termasuk relatif tinggi dibandingkan dengan lokasi lain di Indonesia dan berdasarkan studi lapangan dan analisis data satelit telah berhasil diidentifikasi sebanyak 31 jenis spesies terumbu karang di perairan pesisir Barat Laut Pulau Sumbawa dan Moyo. ...
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Papers by Jonson Lumban-Gaol