Diurnal microclimate profile in tropical coastal built environment (case: Universitas Islam Sultan Agung campus area, Semarang)

Microclimate is caused by the interaction between atmosphere and earth surfaces in local areas. Built environment has pay attention in microclimate since it considerably affects the thermal earth surfaces. This research is located in tropical coastal area, specifically at Universitas Islam Sultan Agung Semarang campus area as a part of built environment where close to the Java sea. The aim of this paper is to investigate the diurnal pattern of microclimate in research location before modelled to the wider area. A numerical modelling method is applied in this research to simulate the diurnal thermal pattern. The research shows that microclimate is influenced by the earth surface objects and following the sun movement respectively.

Pemodelan Sistem Karbonat di Laut Jawa

<p class="Papertext"><strong>Modeling Carbonate System in the Java Sea</strong>. Besides the global fossil fuel burning activities, forest fires in Kalimantan could potentially increase atmospheric CO₂ concentrations, impacting air-sea CO₂ gas exchange in the Java Sea and changing the balance of the marine carbonate system. This study uses a marine carbonate model to examine the processes that control CO₂ flux in the Java Sea and their relationship to CO₂ increase in the atmosphere. OCMIP-2 (<em>Ocean Carbon-Cycle Model Intercomparison Model Project, Phase-2</em>) is performed in this marine carbonate model coupled with the marine ecosystem model. The model results show that the quantity of carbon air flux differs during February and October 2000. More considerable flux is produced during February 2000, where the wind speeds are higher than in October 2000. However, the wind speeds have less impact when the CO₂ level in the atmosphere rises significantly. Due to the influence of a relatively high surface temperature in the tropical Java sea, the Java Sea functions as a carbon source to the atmosphere in general. In this case, the role of the <em>solubility pump</em> is more significant than that of biological processes in carbon absorption. Moreover, increased CO₂ in the atmosphere could alter the partial pressure equilibrium. In the case of 2002 forest fires (atmospheric CO₂ = 460 ppm), the carbon source of the Java Sea was less than before forest fires and even became carbon sink when atmospheric CO₂ rose to 1135.2 ppm based on the highest SSP scenario in 2100. This modeling also reveals marine acidification issues and could rapidly assess the future changes in marine ecosystems due to CO₂ levels rising in the atmosphere.</p>

Persebaran Penyakit di Kawasan Laut Jawa Abad XIX - XX

This article discussed about the process of diseases spreading along the Java Sea area during the 19th and the early 20th century. This study utilized historical method with an aim to reconstruct past events, especially on the outbreaks happened in the Java Sea area and how the colonial governmnet dealt with the occurrence. The article applied Braudel’s structural theory (1988) to analyze the existence of structures, which were taking a role in the process of diseases spreading. This analysis was supported by the concept of ‘silent barter’, developed by Knapen (1995) as a benchmark to determine factors that caused the spread. The results allowed us to discover that the dynamics of shipping and trading in the Java Sea at that time were part of the whole pandemic situation. There were at least two diseases discussed as the main focus of this article, smallpox and cholera, as these two severely affected the trading and shipping activity. These diseases were carried by the crews of ships escaping the quarantine doctors who carried out medical examination at various ports. Several ports in Java, such as Batavia, Semarang, Cirebon, and Surabaya, had become the epicenters of the outbreak. The government applied a regulation to attached a yellow flag to the ship contaminated by the plague before they entered the port area. The yellow flag functioned as an identifying marker. The regulation was supposed to limit the spread of diseases from the coastal area of Java to the mainland, as well as to gain more attention from other ships and doctors resided near the ports. The yellow flag system made it easier for the government and doctors to handle smallpox and cholera outbreaks, even though there had been some aberrations in economic activities in this area.

Spatial and temporal variability of satellite sea surface temperature in the Makassar Strait and the Java Sea

Sea surface temperature (SST) data obtained from the Aqua-MODIS satellite from 2002 to 2012 were analyzed to determine the spatial and temporal variability in the key region of small pelagic fisheries between Makassar Strait and the Java Sea. Results of the Empirical Orthogonal Function (EOF) analysis show that the characteristics of this region are described by 60% based on the greatest contribution value respectively. The largest contribution of 52% shows that the SSTs in this region is warm. A strong indicator of these conditions appears in the east through the southern part of Kalimantan Island while the weak indicator is in the south to western part of Sulawesi Island. The temporal variation shows that the annual oscillation is dominant in this area where maximum SSTs occurs in the first transitional monsoon (April), while the minimum occurs in the southeast monsoon period (August). The influence of southeast monsoon formats the minimum SSTs area in the south of South Sulawesi that is generated by parallel wind-driven induces to the coast and the divergent current close to the coast. Due to inter-annual variability, minimum SSTs occurs before the El Nino episode whereas the maximum occurs before the La Nina event.

Influence of river discharge on circulation and tidal process in the Java Sea, Indonesia

This study investigates the effect of river discharge in transport and tidal processes in the Java Sea using the Coastal and Regional Ocean Community (CROCO) hydrodynamic model. The model has 20 vertical layers and a horizontal resolution of 1/18 degrees. The oceanic and atmospheric forcing of this model is taken from the global Copernicus Marine Environment Monitoring Service (CMEMS) model and the fifth generation ECMWF atmospheric reanalysis (ERA5) hourly data. Daily Global Flood Awareness System (GloFAS) data has been successfully implemented as river flow data for this study. Two scenarios have been applied, namely, with and without river discharge. This study shows that the two scenarios and the satellite observational data agree in terms of water level with Root Mean Square Difference RMSD) about 4 cm, Sea Surface Temperature with RMSD about 0.29 °C, and Sea Surface Salinity with RMSD about 0.39 psu. The model was also validated using seven tide gauges and produced a good agreement. River discharge increase eastward transport in the eastern part of the Java Sea up to 0.1 Sv (1 Sv= 106 m3s−1). Both scenarios produce similar tidal amplitude and phase and agree well with previous studies and other tidal data sources.

Gas Injection Optimization to Increase Oil Production at MRA PT. PHE ONWJ

The MRA platform is one of the offshore platforms located in the north of the Java Sea. The MRA platform has 4 production wells, namely MRA-2ST, MRA-4ST, MRA-5, and MRA-6 wells. The 4 production wells are produced using an artificial lift in the form of a gas lift. The limited gas lift at the MRA Platform at 3.1 MMSCFD makes the production of wells at the MRA Platform not optimal because the wells in the MRA Platform are experiencing insufficient gas lift. Optimization of gas lift injection is obtained by redistribution of gas lift injection for each. The results of the analysis in this study indicate that the optimum gas lift injection for the MRA-2ST well is 0.5552 MMSCFD, the MRA-6 well is 1.0445 MMSCFD, the MRA-5 well is 0.7657 MMSCFD, finally the MRA-4ST well with gas injection. lift is 0.7346 MMSCFD. The manual gas lift in the MRA-4ST is also replaced based on an economic feasibility analysis to ensure that the gas lift injection for each well can be kept constant. The redistribution of gas lift carried out by the author has increased the total production rate of the MRA Platform by 11,160 BO/year or approximately USD 781,200/year. Keywords: Gas lift; Insufficient; Optimization

Modelling sea surface currents in the eastern coast of Bawean Island, East Java

Bawean Island is located in the middle of the Java Sea, approximately 80 km north of Gresik Regency, East Java Province. The coastal area of Bawean Island is famous for its potential as a marine tourism area because it has a well-preserved coral reef ecosystem. The potential for tourism development on this island requires the support of environmental suitability. The dynamics of ocean currents as an important parameter for small island development is important to be analyzed. This study aims to determine the characteristics of currents in the eastern coast of Bawean Island through the hydro-oceanographic model. The data used in this modelling was hourly wind and tide data from the period of 2020-2021. The results showed that the velocity of surface current speed in the study area was weak (<0,5 m/s). There was a significant difference of current direction during the west monsoon season and the first transitional season. Validation of model simulation and ADCP measurements produce MAE values 0,014 and 0,035 as well as MAPE values 12,75% and 27,48%.

Potential of salt as salt body scrubs to support salt tourism in Pamekasan, Madura Island, East Java

Madura Island is famous as the salt island and surrounded by Madura Strait and Java Sea has the potential for marine tourism development, one of which is a salt tourism in Pamekasan Regency. Dissemination of cosmetic salt (salt body scrub) to salt farmers in Pamekasan has been organized by Department of Marine Affairs and Fisheries of Pamekasan in 2018 so that they have the skill of local salt diversification into added value products. Diversification of salt as body care products (salt body scrub) can be packaged into an education-ecotourism package which is tourist attraction so that salt body scrubs have business potential to support salt tourism. This paper studies the use of unrefined salt as salt body scrubs and is expected to be a reference for coastal communities, especially salt farmers in Pamekasan that is to support salt tourism and increase the added value of local salt.

The application of coupled 3d hydrodynamic and oil transport model to oil spill incident in karawang offshore, indonesia

This study presents a coupled hydrodynamic and oil transport numerical model to study the spread of Karawang oil spills at sea due to well-kick failures. This model uses the 3D configuration of ROMS-CROCO in the Java Sea. The model has a resolution of 1 km, 25 vertical layers, and runs from January 2019 to September 2019. Temperature, salinity, sea surface height, ocean currents, and harmonic tides are derived from global models and applied to open boundaries. Hourly atmospheric datasets during model simulation are forced as flux input in the surface. The 3D profile of the flow generated by the model is converted to the GNOME oil transport model format as mover type input to disperse the oil. The hydrodynamic model shows that the result has a good agreement with in-situ data and observation with mean of correlation exceeding r>0.8 for sea surface height and sea surface temperature. Compared with radar satellites, oil spill dispersion shows the same scattered trend as satellite data. Backward modelling shows oil particles returning to the initial spill location. The oil spill was moving westward, and some are stranded on the coast between Karawang and Bekasi.