Indonesian Journal of Geography
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Spatial Distribution Pattern of Covid-19 Cases and Their Characteristics In DKI Jakarta and Surrounding Areas
Full text linkThe COVID-19 pandemic has significantly affected various countries worldwide, including Indonesia. This study specifically examines the spatial distribution pattern of COVID-19 cases among sub-districts in DKI Jakarta and its neighboring areas. The study investigates the impact of spatial characteristics such as building density, population density, road network connectivity, and accessibility, as well as infrastructure completeness. A spatial regression model was employed to analyze the influence and pattern of COVID-19 case distribution among sub-districts. Spatial modeling indicates that geographic location has an effect on the data, often referred to as the autocorrelation effect. Moran’s Index was used to test the relationship between district locations and the number and growth rate of cases.The study findings reveal a positive spatial autocorrelation in the growth rate pattern of COVID-19 cases among sub-districts and clusters in DKI Jakarta and its surrounding areas. The spatial regression model, specifically the Spatial Autoregressive Model (SAR), identifies road connectivity, number of health centers, building density, and population density as spatial variables that significantly influence the rate of COVID-19 cases
Ancient Disaster, the Cause of the Burial of the Kumitir Archeological Site
Full text linkThe Kumitir site, associated with the Majapahit Empire, is a significant archeological discovery. Archeologists from the East Java Cultural Heritage Preservation Center (BPCB), uncovered a structure at this site, buried beneath boulder-sized rocks. According to historical literature, the collapse of Majapahit was caused by volcanic eruptions from the Anjasmoro, Arjuno, or Welirang complexes. Therefore, this study aimed to recreate the gravity-driven mass flow covering the Kumitir Site. Geological surveys, including sediment structure analysis and grain orientation measurements, were conducted to provide new information on paleocurrent and ancient sedimentary processes at the site. Digital Elevation Map (DEM) and the Laharz simulation tool facilitated the creation of reconstructed lahar flow maps using open-source DEM data with an eight-meter resolution. The results of the boulder analysis showed that a paleochannel played a significant role in the burial site, with two sources identified, namely Mount Welirang (Welirang alluvial fan) and the Anjasmoro complex (Old Jatirejo alluvial fan). Meanwhile, the combination of methods applied signified the direction of the Welirang alluvial fan (ESE-NNW) and the Jatirejo Tua alluvial fan (SSW-NNE). Volumes of 9 million m3 and 65 million m3 were the most relevant parameters for estimating the lahar flows of the western and eastern craters, respectively
Analyzing Free Economic Zones in Uzbekistan for Sustainable Growth
Full text linkThis study examines the economic geography of Uzbekistan's free economic zones, focusing on their current significance and future prospects. It examines the historical and theoretical foundations of these zones, focusing on their role in shaping and organizing them. The study looks at the status of the free economic zones and examines their contribution to key economic indicators such as gross domestic production, trade, labor and tourism. In addition, the study uncovers the challenges faced by the free economic zones and provides targeted recommendations to effectively address these issues. The findings not only contribute to the existing economic geography literature, but also serve as a valuable resource for policy makers, researchers and stakeholders interested in promoting economic growth and regional development through free economic zones. This study provides a comprehensive analysis and a theoretical basis for understanding free economic zones in Uzbekistan and offers a broader perspective for improving their performance and potential to ultimately promote sustainable economic development in the country and beyond
Comparison of All Return Cover Index (ARCI) and First Return Cover Index (FRCI) Methods for Mapping Percentage of Mangrove Canopy Cover using LiDAR Data
Full text linkIndonesia has the largest mangrove forest in the world, around 3.3 million hectares or 19.5% of the entire mangrove’s world population. Mangroves have many ecological and economic benefits and are also threatened by several conditions, such as a decrease in area, land, degradation, and the health of mangrove vegetation. One of the methods in maintaining the sustainability of mangrove ecosystems is mapping the biophysical aspects of vegetation, namely mapping the percentage of mangrove canopy cover using field measurements or remote sensing. This study aims to compare the accuracy of Light Detection and Ranging (LiDAR) data based on All Return Cover Index (ARCI) and First Return Cover Index (FRCI) algorithms in mapping the percentage of mangrove canopy cover and analyzing its spatial distribution. The study area is a mangrove forest in Ratai Bay Pesawaran Lampung. This forest is dominated by a dense and evenly distributed canopy cover class with an average value of 78.24% which was acquired using the hemispherical photography method. ARCI and FRCI methods are dominated by the dense and evenly distributed cover class with an average percent cover value of 85.39% and 89.78%, respectively. The accuracy of mapping the percentage of mangrove canopy cover using FRCI is higher than ARCI, with a maximum accuracy value of 93.08% and a standard error of 5.95%. That value shows that using LiDAR data with the FRCI method for mapping the percentage of mangrove canopy cover produces a high accuracy value
Estimation of Nitrogen Content of Rice Crops Using Sentinel-2 Data
Full text linkNitrogen (N) is one of the most essential nutrients for rice crops. Farmers generally provide Nitrogen requirements in rice through fertilization, but the fertilization process is only based on an estimation without calculating the amount needed first. However, neither insufficient nor excessive nitrogen content is good for rice crops, and the nitrogen needs of rice crops are different at each growth stage. The nitrogen requirement in the generative phase is relatively high because the process of panicle formation and grain filling occurs at this stage. Several methods can be used to monitor nitrogen content in rice, one of which is using remote sensing methods. With the vegetation index approach, the nitrogen content of rice plants is estimated through data analysis of the light spectrum reflected by the leaf. Sentinel-2 satellite imagery was used in this research, and several vegetation indexes such as OSAVI, GNDVI, and SRRE were applied to form an estimation model using the regression method. From the results, three vegetation indexes positively correlate with nitrogen content in rice crops. The SRRE index gives the highest correlation coefficient value of 0.692, while the correlation coefficient value for GNDVI is 0.498, and OSAVI is only 0.470. The estimation map of the nitrogen content of rice crops was obtained based on the estimation model made by linear regression between SPAD-based nitrogen content data and the best vegetation index using the SRRE index. The analysis shows that the nitrogen content of rice plants estimated in the paddy fields of Karangjati Subdistrict is dominated by nitrogen values with optimum classification
Climate Change Adaptation in Batang Hari, Jambi: A Case Study of Rainfed Paddy Farmers
Full text linkBatang Hari is situated as one of the central rice-producing regencies within Jambi Province. However, the agricultural sector in Batang Hari is severely impacted by climate change in the context of productivity. This study aimed to examine rainfall and temperature trends over the last 20 years (2002 to 2021), assess farmers' perceptions, and identify the current adaptation measures due to the impact of climate change on rainfed paddy fields. This study is of great importance because it employs a holistic approach, integrating quantitative data on climate trends with qualitative insights from farmers. The results showed that rainfall decreased by 20–50 mm/month, and the average temperature increased by 0.4°C in 20 years. The qualitative data on farmers' perceived impact of changes in climate variability reported an agreement with climatological data. The farmers perceived a decrease in rainfall and a concurrent rise in temperatures. Furthermore, a delayed onset of the rainy season was noted, leading to an adjustment of their planting schedules. Certain adaptation measures to adjust to the perceived impact of changes in climate variability on their rainfed paddy fields were also implemented. These measures included crop management as well as socio-economic adaptation. Farmers' adaptation measures included modifying crop varieties, adjusting planting seasons, adopting agricultural machinery, and diversifying income through off-farm activities. It is also important to emphasize technological based adaptation to enhance climate resilience, as well as sustainable land management practices, agroforestry initiatives, and soil conservation efforts for long-term agricultural sustainability
Flood Vulnerability Analysis Based on GIS and Remote Sensing at Silat Hulu
Full text linkA flood is a natural disaster that may happen anywhere and anytime. These disasters have become an annual cycle in Indonesia, and it is important to be swift in their mitigation and control. This study aims to determine the vulnerability of flooding in Silat Hulu and the extent of the area likely to be submerged. The method used was survey and secondary interpretation data. Data was from topographic maps, Sentinel 2A images, and 10 x 10 m resolution DEM images acquired on November 21, 2021, obtained from the ALOS PALSAR imagery. Data analysis using ArcGIS 10.8, using the weighted overlay spatial analysis tool. The results showed that the study location had three flood vulnerability classes: low, medium, and high. The locations with low vulnerability classes have an area of 2,921 ha, moderate have 32,683 ha, and high have 28,208 ha. Low flood vulnerability is spread to a small extent in Nangau Luan, Nangau Lungu, and Landau Badai villages. The level of vulnerability is mostly in Nangau, Nangau Lungu, and Landau Storm. The high level of vulnerability is mainly spread in the villages of Nangau Dangkan, Blimbing, Nangau Ngeri, and Nangau Lungu. GIS and remote sensing approaches are practical tools for flood-prone maps. Furthermore, GIS-based flood vulnerability mapping and remote sensing are valuable tools for estimating flood vulnerability areas
Runoff Coefficient in the Air Bengkulu Watershed and the Evaluation of the Existing Spatial Planning
Full text linkRunoff coefficient plays a crucial role in estimating the peak discharge of a river basin. Therefore, this research aimed to investigate runoff coefficient in the Air Bengkulu watershed based on temporal land cover data and evaluate the existing spatial planning. Land cover data from 1998, 2002, 2016, and 2023, with spatial patterns derived from current regional planning were used. The temporal and spatial pattern-based runoff coefficients were determined using land cover data and spatial pattern function, respectively. Meanwhile, descriptive and comparative methods were adopted based on time. The calculated runoff coefficient was 0.073, 0.093, 0.276, and 0.273 for 1998, 2002, 2016, and 2023, while the value obtained based on spatial patterns was 0.306. Additionally, a general trend of increasing the values over time was observed. Land cover change, particularly the decline of forest areas and the expansion of settlement and plantation, contributed to the rising runoff coefficient. The results showed that runoff coefficient (0.306) exceeded the current land cover, similar to other analyses with higher runoff in the predicted scenario. This research suggested a need for a more detailed classification system and scale to accommodate land cover types with relatively low runoff coefficient. In risk assessment, land cover-like spatial patterns with low runoff coefficient should be placed as capacity other than vulnerability components
Synoptic Conditions at Pressure Different Levels for the Dust Storm of May/ 2022 Over Iraq
Full text linkThis study examines the severe dust storm from May 12-16/2022,culminating on May 15, with a comprehensive analysis and explanation. The weather maps from the National Oceanic and Atmospheric Administration (NOAA) and the European Centre for Medium-Range Weather Forecasts (ECMWF) weather maps were used to identify systems and patterns that contributed to the storm's activity, continuity, and tracking as well as maps of pressure compounds and wind vectors in levels 1000 and 850 mbar that appear with the dust state for the same days accompanied by tracking patterns in the middle of the turbosphere 500 mbar to give a comprehensive analytical view of climate conditions at each level of pressure and higher systems supportive of their persistence on the surface. The northwesterly winds are the main factor that carries dust over long distances. The eastern desert in Syria, the Empty Quarter in the Kingdom of Saudi Arabia, the desert of western Iran, and the desert region of western Iraq are among the main sources of dust In its atmosphere. Based on weather maps of the surface and upper levels of storm days, the concentration of dust reached very high levels in Iraq's airspace and surrounding countries, including Egypt, Jordan, Lebanon, Palestine, and Syria. The intensity of the dust gradually decreased as the area was affected by wet westerly winds with relatively low temperatures and a relative increase in wind speeds due to the impact of the study area on the atmospheric decline centered around the Turkish island of Cyprus
Discovery of Marine Macrozoobenthos Fossils in the River of Wonocolo Geosite, Indonesia
Full text linkWonocolo Geosite is a geoheritage known for the existence of the Kawengan Anticlinal Trap, which is the only one in the world, causing oil to be found in shallow locations. This condition has allowed for traditional mining since the Dutch colonial era and continues today. Geological history states that the anticlinal structure was formed when the Indo-Australian plate collided with the Eurasian plate, resulting in folds and uplift of the seafloor above the surface. However, there has not been much research supporting the truth of the theory. Therefore, evidence is needed to support the uniqueness of the Wonocolo Geosite. The fossil collection method was carried out simultaneously with the collection of substrates at the upstream, middle, and downstream riverbeds using 20 cm diameter PVC pipes at a depth of 10 cm.This study found marine macrozoobenthos fossils during substrate sampling in the upstream, middle, and downstream river beds using a PVC pipe with a diameter of 20 cm at a depth of 10 cm. The samples were then identified in the laboratory, revealing fossils from the deep sea. The fossils found include Azooxanthellate (Cnidaria), which lives at depths of up to 2000 m; Dentaliida (Mollusca) which lives at depths of 500-7000 m and Foraminifera which also live in the deep sea. This phenomenon is unusual, considering that the fossils were found in a river far from the sea at an altitude of 250 MASL. Therefore, the discovery of marine macrozoobenthos fossils at the bottom of the Wonocolo River strengthens the theory of the formation of the Wonocolo Formation from a raised seabed which is also an important asset supporting the Wonocolo Geoheritage