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Thermal Comfort for various Altitudes and Land Covers in North Sumatra
Full text linkThermal comfort refers to the suitability of meteorological conditions for humans with the environment. Temperature is the main meteorological variable, which determines the thermal comfort as expressed in various climate indices. This study aims to analysis the distribution of thermal comfort, and to identify environmental factors influencing the comfort situated in North Sumatra, Indonesia. We applied the Universal Thermal Climate Index (UTCI) to determine the heat stress level for 2011 - 2020. The higher UTCI value indicates more uncomfortable conditions related to the higher heat stress. The results showed that the average value of UTCI in North Sumatra was categorised at moderate heat stress. Densely urbanised area in the eastern region contributed to high heat stress, whereas mountainous areas in central to west regions were at low level. Our findings found that climate season affected the distribution of heat stress level. The low heat stress occurred in December-February, while high heat stress happened in June-August. Further, findings revealed that altitude and land cover have contributed to UTCI variation by more than 75% variance
The Study of Wind Field ERA-20C in Monsoon Domains for Rainfall Predictor in Indonesia (Java, Sumatra, and Borneo)
Full text linkIn recent years, various research institutions have developed diverse global data reanalysis projects. This provides an opportunity to gain long-term of meteorological data for local scale. This study aims to select the potential predictor of wind fields u and v of the ERA-20C dataset, a reanalysis dataset, at 850 mb from seven domains or windows of Asian, Maritime Continent, Australian, and Western North Pacific monsoon related physically to rainfall anomaly patterns in Indonesia. The vector wind velocity scalar was obtained by using a Helmholtz decomposition to separate the total circulation v = (u,v) into the divergent component/velocity potential (χ) or Phi and rotational component/stream function (ψ) or Psi for obtaining the scalar variable of vector wind velocity. The method applied Singular value decomposition (SVD) to identify pairs of spatial patterns (expansion coefficients) between the predictors of Phi and Psi in seven domains, with rainfall data from 48 stations in Java, Sumatra, and Borneo Islands from 1981 to 2010. The results revealed that spatial patterns correlations of Java Islands were the highest in the Maritime Continent monsoon domain (80o−150o E and 15oS−15o N), while Sumatra and Borneo Island were in the Western North Pacific monsoon domain (100o–130o E and 5o–15o N) with predictor Psi. The lowest correlation for Java, Sumatra, and Borneo was the Australian monsoon domain (110o E–130o E and 5o S–15o S) with predictor Phi. In general, spatial pattern correl-ations of Java Island were higher than others, agreeing with monsoonal rainfall type dominantly in the region
Systematic Literature Review on Ozone Dispersion Correlated with Diurnal Concentration Pattern in Urban and Rural Areas
Full text linkGround level ozone is known to exhibit a strong daily variation of concentration leading to long-range transport of air pollutants from urban to rural areas. Moreover, the characteristics of O3 relationship between urban, suburban, and rural sites can be explained by O3 photochemical chemistry and meteorological dispersions as indicated by the different result of O3 diurnal pattern. However, little is known about the global phenomenon of diurnal concentration of ozone, meteorological dispersion such as long-range transport, and their correlation with ozone precursors, especially in urban and rural areas. This paper attempt to compare the difference between daily ozone fluctuations in both sites and assess some factors that cause long-range ozone transport from urban and rural areas both in subtropical and tropical areas for global scale. Using systematic literature review analysis with the PRISMA method, it examined 43 peer-reviewed articles published between 2010 and 2022 globally meeting the inclusion criteria. The result showed that the fluctuation patterns of daytime ozone in urban and rural areas are different to those in tropical and subtropical regions, depending on latitude. This was primarily due to the influence of solar radiation and the presence of precursors. Conversely, a slight decrease in ozone rate at night occurs because the precursor was accumulated by the shutdown of photochemical ozone production. Some precursors of ozone from other regions can be transported and accumulated from the long-range transport process in other locations. This paper serves as an initial guideline to analysing the pattern of ozone concentration in urban and rural areas and the factors that influence it
Land Use Change Impact on Normalized Difference Vegetation Index, Surface Albedo, and Heat Fluxes in Jambi Province: Implications to Rainfall
Full text linkJambi covers various land uses with different characteristics related to biogeophysical cycle. Land use plays an important role in the atmosphere-surface interaction and energy balance partition, which influenced rainfall pattern. Two proxies widely used to differentiate various land uses are albedo and normalized difference vegetation index (NDVI). However, study on albedo and NDVI relationship with rainfall in Jambi is still limited. This study aims to analyze the correlation of NDVI and albedo with rainfall and their distribution in Jambi and Muaro Jambi in 2013 and 2017. The research used Landsat 8 OLI TIRS satellite image data to derived NDVI and albedo, and CHIRPS data for rainfall. A simple linear regression was used to calculate the correlation of NDVI and albedo with rainfall. The results showed that the distribution of albedo for each land use class from the lowest to the highest was forest, plantation, cropland, shrubs, and settlements, respectively. On the contrary, the distribution of NDVI and rainfall is the inverse to albedo. Albedo and NDVI had a strong influence on rainfall through surface energy balance partition. This was indicated by the high R-square between albedo and rainfall (0.99) and between NDVI and rainfall (0.97). Increasing upward latent heat flux from the land surface to atmosphere leads to a rainfall increase. In other words, rainfall may also increase with the decrease in albedo, increase in NDVI, or land use change
Identification of Climate Trends and Patterns in South Sumatra
Full text linkSouth Sumatra is one of low-lying provinces in Indonesia with a vast area of peatland that is prone to peat fires and floods. Understanding climate patterns in South Sumatra is very important to anticipate the impacts of extreme weathers. This study identified the climate trends and patterns based on the daily data of temperature, rainfall and evapotranspiration obtained from 1975 to 2021 (46 years). Here, the trend and its significance were detected based on the linear regression and Mann-Kendall test approaches. Characteristics of wet/dry season (start, peak, end) were identified annually based on the 6th polynomial equation using rainfall and evapotranspiration data. The results show an increased trend of annual average temperature (0.04oC per year), rainfall (6.83 mm per year), and evapotranspiration (0.77 mm per year). Other findings reveal that the cyclic season in South Sumatra is wet season (starts from 1±30 to 163±79 Julian day), followed by dry season (from 172±152 to 273±90 Julian day), then wet season (until 244±90 Julian day). The mean excess of annual rainfall was 708 mm (593 mm and 114, respectively, for wet and dry season). Further, we found that South Sumatra experienced extreme dry season (8 times) with the longest in 2019 that lasted for 167 days in a row. As a precaution, extreme wet spells may occur in November-December, and March, whereas extreme dry seasons can be found in July-September each year
Baseflow Index Analysis for Bengawan Solo River, Indonesia
Full text linkHydrological investigation for major Java rivers remains research challenge todays, particularly in identification of runoff characteristics situated in monsoonal climate. This study aims to investigate the value of baseflow index for Bengawan Solo river. We employed daily streamflow data for period 1980-2010 to derive baseflow index (BFI) based on the smoothed minima. We utilized different approaches comprising the non-overlapping 3 days (BFI3), 5 days (BFI5), and 7 days (BFI7) of streamflow to compute the index. We found the average BFI3, BFI5, and BFI7 for this study period are 0.67, 0.56, and 0.49, respectively. It revealed that higher number of non-overlapping days would produce lower BFI, which could be an indication of less baseflow contribution to total streamflow. Additionally, our findings show there is an increasing trend of BFI in the last decade that may be associated with decreasing forest cover in the catchment area. Furthermore, the BFI value will provide a valuable information for key leader in water sector in particular during dry season, and further research is needed to integrate this BFI into sustainable water management index
Optimization of Water Utilization through Identification of Distribution and Types of Water Harvest Infrastructure to Increase Agricultural Production, Study Case in Lampung Province
Full text linkIndonesian government has promoted the acceleration of local reservoirs development in rural areas. This development shall be integrated in agri-cultural areas to increase its production. Therefore, identification of the potential location and the type of water harvesting infrastructure are crucial to support and optimize the reservoir construction. Here, this research aims to identify the potential location distribution and the type of water harvesting infrastructure in Lampung Province. A Geographic Information System analysis was conducted using several base maps and thematic maps to extract each region characteristics, which include land use, rice field location, river network, slope, area status, buffer zone, groundwater basin, and rainfall pattern. In addition, a survey was conducted to identify potential water availability and land area, including flow discharge in each region. The results showed that the most suitable types of water harvesting infrastructure were channel reservoirs, followed by river water utilization and shallow wells. All infrastructures are highly dependent on rainfall. This means that channel reservoirs have the largest potential area for irrigation services, followed by the river water utilization, shallow wells, and small reservoirs (embung), respectively
Bogor Water Adequacy Status for 2009-2019
Full text linkWater adequacy becomes one of the global concerns as the trend of population growth continues to arise. The condition of water adequacy can be worse in some regions since it also relates to rainfall, which is greatly influenced by global climate change. Here we explore water adequacy at local scale especially in Bogor, Indonesia based on sectoral water demands. The study aims to analysis water adequacy for 2009-2019 based on a climatic water balance. Water supply-demand analysis was performed using water usage index (WUI) in which high WUI corresponds to high critical water balance. Our results showed there was a deceased trend for water supply in Bogor approximately 0.6% per year, whereas an increased trend was observed for water demand (1.7% per year). The main contributor for the increased demand was from domestic water demand by 48%. Generally, water adequacy in Bogor for the period analysis (2009 -2019) is still adequate, but a proper management of water resource will ensure water adequacy in the long run in response to population explosion and climate change
Season Onset Prediction Based on Statistical Model for Malang Regency, East Java
Full text linkPrediction of season onset is important for many sectors, particularly on agricultural practices, as its usage for reducing climate risk and planning activities. Current knowledge on season onset prediction mainly focused on large area, which remains research challenge for local level. This research developed model prediction of season onset for Malang Regency, East Java based on global climate data. The research specifically aimed to: (i) determine the onset date of rainy and dry season, (ii) generate equation for onset date prediction using principal component regression (PCR) approach, and (iii) evaluate the model performance. We depend on statistical model based on a combine of domain time and principal component analysis (PCA) for atmospheric variables, namely sea level pressure, outgoing longwave radiation, and zonal wind. We used the Tropical Rainfall Measuring Mission (TRMM) data for model evaluation, especially for determination of onset date. Based on cumulative anomalies rainfall, the onset date for dry season occurred in the early May, whereas for rainy season it was in early November. The results showed that regression models of the principal components had a good skill to predict onset date for both seasons. It has been confirmed by a low error and a high correlation. Visually, the dynamic of onset dates from model was mostly identical to the observation. The predictive model for rainy season had higher performance compared to the model for dry season. This finding was confirmed by insignificant difference resulted from the independent t-test between model and observed onset dates. The best model for dry season was conducted by domain time of February, whereas for rainy season was domain time of August. This research can be used to complement previous studies regarding season onset prediction in Indonesia
Analysis of Crop Water Requirement for Maize with Planting Hole System under Dry Climate Condition
Full text linkCrop water requirement is an important factor to increase water use efficiency and avoid crop failure in dryland. A way to increase water use efficiency is by determining an irrigation interval scenario and utilizing a planting hole system. Research on the analysis of water requirement in the planting hole system with an irrigation interval for maize is still limited. Therefore, this study aims to analyze the level of water requirement for maize in dryland. This research was conducted in Camplong Village, Kupang District, East Nusa Tenggara (NTT) from January-May 2020. The design used was a split-plot of various treatments. There were three different techniques of applying fertilizer as the main plot, and two treatments of pruning maize leaves as sub-plots. The different treatments of fertilizer application includes: 1) mixing manure with rice husk charcoal (Ls+As), 2) separating manure from rice husk charcoal (Ls/As), 3) no addition of manure or rice husk charcoal into the planting hole (control). The sub-plots were divided into 2 treatments namely with leaf pruning (P) and without leaf pruning (TP). The water requirement was analyzed based on the FAO 56 approach with the production calculation in weight unit of tiles (ubinan). The results showed that 75% water efficiency was achieved or there was a water saving of 3,119 m3/ha/planting season when compared to conventional techniques. The highest maize productivity (7 tons/ha) was attained in treatment of mixing manure with rice husk charcoal with leaf pruning. The result indicated that this water savings may be used to expand the planting area to 3 ha