bluuebunny/crossref_metadata_2025 huggingface dataset:
Interactive influence of ENSO and IOD on contiguous heatwaves in Australia
Authors: Reddy P Jyoteeshkumar , Perkins-Kirkpatrick Sarah E , Sharples Jason J
Published: December 2021

Australian heatwaves have a significant impact on society. Most previous studies focus on understanding them in terms of frequency, duration, intensity, and timing. However, understanding the spatial characteristics of heatwaves, particularly those occurring in contiguous regions at the same time (here referred to as contiguous heatwaves), is still largely unexplored. Here, we analyse changes in spatial characteristics of contiguous heatwaves in Australia during 1958–2020 using observational data. Our results show that extremely large contiguous heatwaves are covering significantly larger areas and getting significantly longer during the recent period (1989/90–2019/20) compared to the historical period (1958/59–1988/89). We also investigated the association of contiguous heatwaves in Australia with interactions of the El Niño–Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD) using a large multi-member ensemble of a physical climate model. We found that areal magnitude, total area, median duration, and maximum area of large and extremely large contiguous heatwaves in Australia are significantly higher (lower) during the strong El Niño (Es), strong El Niño co-occurring with strong IOD positive (Es-IPs), and with moderate IOD positive (Es-IPm) (co-occurring strong La Niña with the strong IOD negative (Ls-INs)) seasons relative to the neutral seasons (where both ENSO and IOD are in neutral phase). During the Es, Es-IPm, and Es-IPs seasons, the large-scale physical mechanisms are characterised by anticyclonic highs over the southeast and cyclonic lows over the northwest of Australia, favouring the occurrence and intensification of heatwaves in Australia. These results provide insights into the driving mechanisms of contiguous heatwaves in Australia.
Regionalizing crop types to enhance global ecosystem modeling of maize production
Authors: Yang Yi , Ogle Stephen , Del Grosso Stephen , Mueller Nathaniel , Spencer Shannon , Ray Deepak
Published: December 2021

Improving the prediction of crop production is critical for strategy development associated with global food security, particularly as the climate continues to change. Process-based ecosystem models are increasingly used for simulating global agricultural production. However, such simulations often use a single crop variety in global assessments, implying that major crops are identical across all regions of the world. To address this limitation, we applied a Bayesian approach to calibrate regional types of maize (Zea mays L), capturing the aggregated traits of local varieties, for DayCent ecosystem model simulations, using global crop production data from 2001 to 2013. We selected major cropping regions from the FAO Global Agro-Environmental Stratification as a basis for the regionalization and identified the most important model parameters through a global sensitivity analysis. We calibrated DayCent using the sampling importance resampling algorithm and found significant improvement in DayCent simulations of maize yields with the calibrated regional varieties. Compared to a single type of maize for the world, the regionalization of maize leads to reductions in root mean squared error of 11%, 31%, 27%, 30%, 19%, and 27% and reductions in bias of 59%, 59%, 50%, 81%, 32%, and 56% for Africa, East Asia, Europe, North America, South America, and South and Southeast Asia, respectively. We also found the optimum parameter values of radiation use efficiency are positively correlated with the income level of different regions, which indicates that breeding has enhanced the photosynthetic efficiency of maize in developed countries. There may also be opportunities for expanding crop breeding programs in developing countries to enhance photosynthesis efficiency and reduce the yield gap in these regions. This study highlights the importance of representing regional variation in crop types for achieving accurate predictions of crop yields.
On two reversible cellular automata with two particle species
Authors: Klobas Katja , Prosen Tomaž
Published: December 2021

We introduce a pair of time-reversible models defined on the discrete space–time lattice with three states per site, specifically, a vacancy and a particle of two flavours (species). The local update rules reproduce the rule 54 reversible cellular automaton when only a single species of particles is present, and satisfy the requirements of flavour exchange (C), space-reversal (P), and time-reversal (T) symmetries. We find closed-form expressions for three local conserved charges and provide an explicit matrix product form of the grand canonical Gibbs states, which are identical for both models. For one of the models this family of Gibbs states seems to be a complete characterisation of equilibrium (i.e. space and time translation invariant) states, while for the other model we empirically find a sequence of local conserved charges, one for each support size larger than 2, hinting to its algebraic integrability. Finally, we numerically investigate the behaviour of spatio-temporal correlation functions of charge densities, and test the hydrodynamic prediction for the model with exactly three local charges. Surprisingly, the numerically observed ‘sound velocity’ does not match the hydrodynamic value. The deviations are either significant, or they decay extremely slowly with the simulation time, which leaves us with an open question for the mechanism of such a glassy behaviour in a deterministic locally interacting system.
The Advantages of Implementing Integrated Farming Systems For Integration of Goats and Ducks with Terubuk (Saccharum edule Harl)
Authors: Sukmawani Reny , Putriyana Aulia Miftahunnisa Exa , Andayani Sri Ayu
Published: December 2021

This research was conducted to examine the advantages of the application of integrated farming systems between goats and ducks with terubuk in Sukabumi. The research is a case study from the farmers who adjust integrated farming systems then the data was analyzed descriptively qualitative. The result of the study show that the application of this integration between goats and ducks with terubuk has advantages in terms of cultivation, social and economic aspects. Based on the cultivation aspect, this system is efficient because of the continuous availability of feed. Furthermore, based on social aspect can minimize problems such as problem that arise due to presence of waste that cause pollution can be overcome because of the use of waste are more useful. Economic aspect of this system to be efficient because of an increase in income by reducing expenses for feed by 60% and reducing fertilizer requirement by 100%
Analysis of precipitation microstructure characteristic during Madden Julian Oscillation (MJO) using micro rain radar (MRR) and disdrometer in South Tangerang
Authors: Nurheliza D , Trilaksono N J , Renggono F
Published: December 2021

Rain microstructure is a critical aspect to understand the dynamics and microphysics character of the clouds. It is characterized by the distribution of size, fall velocity and shape of raindrop. Raindrop size distribution (DSD) explains the detail of the microphysical process because it represents a process of rain to the surface. One of the phenomena that influence the rain patterns in Indonesia is Madden Julian Oscillation (MJO). Therefore, observing rain microstructure with its relation to MJO can determine the differences in rainfall characteristic and microphysical processes during active and inactive MJO period. The data used in this study are Micro Rain Radar (MRR), disdrometer, and real-time multivariate (RMM) index data. The period/date selection of active MJO event performed using RMM index method is more than 1 in phases 4 and 5 and otherwise for inactive MJO. Types of rain are divided into stratiform and convective rain based on disdrometer data. From that, there are 46 active and 52 inactive MJO events. Rain microstructure in this study focuses on DSD from disdrometer and micro rain radar data analyzed with liquid water content profile, fall velocity, reflectivity, and rain rate from MMR. Besides, there are parameters of DSD, which are the mass-weighted diameter (Dm) and total concentration (Nw), calculated using the moment and gamma distribution method. The result shows that DSD and other parameters are greater during inactive MJO period. It means that process of collision-coalescence, evaporation, and updraft is dominant during inactive MJO period.
Analysis PM10 and Visibility During Forest Fire in Palangka Raya
Authors: Indrawati A. , Andarini D. F. , Cholianawati N. , Sumaryati
Published: December 2021

Forest fires have an impact on air quality and visibility. Visibility can be associated with a highly visual indicator of air pollution. This research aims to analyze the relationship between the PM10 concentration and visibility during the forest firest events and normal conditions in Palangkaraya from 2000 to 2014 by using a regression method. The relative humidity data was used to filter the PM10 and visibility. Furthermore, the equation resulted from the regression analysis was used to predict PM10 concentration in Palangka Raya. The result showed that the regression pattern tends to form a logarithmic function. Specifically, without filtering data, the coefficient correlation (r-value) during the forest fire events and normal conditions are 0.69 and 0.5, respectively. Meanwhile, a data filtering method gives a higher relationship between PM10 and visibility, with the r-value of 0.7 for the forest fire events and 0.68 for the normal condition. On the other hand, the prediction of PM10 concentration indicates a high bias value due to the other influenced factors that have not been included in this study.
Short vertical-wavelength gravity wave activities in the upper troposphere lower stratosphere observed with global navigation satellite system radio occultation under different QBO phases
Authors: Rasyad Firas , Hadi Tri Wahyu , Noersomadi
Published: December 2021

Gravity Waves (GWs) are believed to play important role in the generation of the driving force of the stratospheric Quasi-Biennial Oscillation (QBO). Deep convection in the equatorial region can generate large amount of GW with short vertical wavelength (λz<1 km) but studies of these wave activities in the upper troposphere lower stratosphere (UTLS) region are still limited. Recent advances in Global Navigation Satellite System (GNSS) Radio Occultation (RO) retrieval techniques have made it possible to derive global temperature profile with vertical resolution of less than 1 km. In this research, activities of GW with λzfrom 0.5 to 3.5 km in the UTLS region of 20-27 km heights are identified by calculating the GW potential energy (Ep). Correlation between GW activities and QBO phases is examined using 50 hPa zonal wind as the QBO index. The results show that during both easterly and westerly QBO phases, the GWEpvalue increases gradually with time and reaches its peak in the transition periods. This pattern is seen inEpwith all vertical wavelengths between 0.5-3.5 km but the percentage value ofEpfor λz<1 km is higher during the transition from westerly to easterly QBO. The GWEpvalues exhibit downward propagation with the QBO phase but there are also discernible upward propagations of GW activities below 24 km height and intersect those two bring large changes in QBO phases. Additionally, higher percentage ofEpwith λz<1 km is also found to be associated with El Niño events.
Forest Fire in East Nusa Tenggara during 2015-2019: Comparison to Forest Fire in Kalimantan and Sumatera
Authors: Sumaryati  , Andarini D F , Cholianawati N , Indrawati A
Published: December 2021

East Nusa Tenggara is one of the provinces in Indonesia that has big forest fires following some provinces in Kalimantan and Sumatra. However, forest fires in East Nusa Tenggara have less attention in forest fires discussion in Indonesia. This study aims to analyze forest fires in East Nusa Tenggara and their impact on reducing visibility and increasing carbon monoxide (CO) from 2015 to 2019. In this study, hotspot, forest fire area, Oceanic Niño Index, visibility, and CO total column data were used to analyze the forest fires using a statistical comparison method in East Nusa Tenggara, Kalimantan, and Sumatra. The result shows that the number of hotspots in East Nusa Tenggara less than in Kalimantan and Sumatra for the same forest fire area. The forest fires in East Nusa Tenggara do not harm the atmospheric environment significantly. East Nusa Tenggara dominantly consists of savanna areas with no peatland, hence, the forest biomass burning produces less smoke and CO. Furthermore, the forest fire in East Nusa Tenggara has not an impact on decreasing visibility and increasing CO total column, in contrast, visibility in Sumatra and Kalimantan has fallen to 6 km from the annual average, and CO total column rise three times of normal condition during peak fire.
Analysis of Multi-Scale Hydrometeorological Triggering Flash Flood Event of the 13 July 2020 in North Luwu, South Sulawesi
Authors: Paski J A I , Makmur E E S , Permana D S , Nurrahmat M H , Praja A S , Riama N F , Fitria W , Hartanto
Published: December 2021

During 12-13 July 2020, heavy rainfall had caused Masamba, Rongkong, and Rada rivers to overflow, causing flash floods in the North Luwu regency. This event resulted in many casualties; at least 38 people died and displaced thousands of people. This study presents an analysis of the multi-scale hydrometeorological settings that led to the development of these intense storms in the North Luwu fl ood. Boreal Summer Intraseasonal Oscillation (BSISO) Normalized PC2 has entered phases 4 and 5 on 7 - 13 July 2020, associated with cloud growth in the Indonesian Maritime Continent. Besides, the sub-seasonal tropical disturbance of Kelvin Waves is convectively active in the Sulawesi region on 7 - 13 July, increasing the intensity of rainfall at the location. Sea Surface Temperatures (SSTs) were in warmer conditions in the Bonne Bay region south of North Luwu, supplying more water vapor into the atmosphere. The easterly wind (Australian monsoon) enhanced the diurnal cycle of the water vapor mass movement from Bonne Bay to the highlands of North Luwu. From the observation of GPM satellite imagery, the accumulation of spatial rainfall on July 12 and 13 was concentrated in the eastern region of Sulawesi, which reached >150 mm/day and >50 mm/day in North Luwu.
Study of Mesoscale Convective Complex (MCC) and its impact over the Makassar Strait (case study: 9 December 2014)
Authors: Ni’amillah A , Ismail P , Siadari E L , Saragih I J A
Published: December 2021

A mesoscale Convective System (MCS) is a system consisting of groups of convective cells in the mesoscale. One of the largest types of MCS subclass is Mesoscale Convective Complex (MCC) occurred in the eastern part of the Makassar Strait near the Madjene and Polewali Mandar regions on 9 December 2014, morning to evening (09.00-15.00 LT). Using MTSAT-2 Satellite Imagery data, reanalysis of the European Centre for Medium-Range Weather Forecasts (ECMWF) interim era, the Global Satellite Mapping of Precipitation (GsMap) rainfall, sea surface temperature, surface air observation, and upper air observation, the author will examine the existence of MCC in the Makassar Strait in terms of atmospheric conditions when MCC enters the initial until extinct and the accompanying effects of precipitation. In general, it is known that the MCC formed in the waters of the Makassar Strait in the morning, and then it moved westward. The mechanism of its formation was through a process of convergence of the lower layers in the waters of the Makassar Strait and its surroundings to trigger the process of cloud formation. Warm thermal conditions also gave a big influence on the lower layers to the top and activate convective in the study area. Meanwhile, the MCC occurrence region also has high relative humidity, negative divergence values, and maximum vorticity values. The impact of the emergence of MCC on that date resulted in areas with very large humidity and cloud formation and produced rain in the surrounding area, in this case using rainfall data from Hasanuddin Meteorological Station, Makassar, South Sulawesi. With a duration of up to seven hours extinct, MCC in the Makassar Strait produces heavy rainfall in the Makassar Strait waters.
Improvement in WRF model prediction for heavy rain events over North Sumatra region using satellite data assimilation
Authors: Saragih Immanuel Jhonson Arizona , Mukhsinin Huda Abshor , Tarigan Kerista , Sinambela Marzuki , Situmorang Marhaposan , Sembiring Kurnia , Humaidi Syahrul
Published: December 2021

Located adjacent to the Indian Ocean and the Malacca Strait as a source of water vapour, and traversed by the Barisan Mountains which raise the air orographically causing high diurnal convective activity over the North Sumatra region. The convective system that was formed can cause heavy rainfall over a large area. Weather Research and Forecasting (WRF) was a numerical weather model used to make objective weather forecasts. To improve the weather forecasts accuracy, especially for predict heavy rain events, needed to improve the output of the WRF model by the assimilation technique to correct the initial data. This research was conducted to compare the output of the WRF model with- and without assimilation on 17 June 2020 and 14 September 2020. Assimilation was carried out using the 3D-Var technique and warm starts mode on three assimilation schemes, i.e. DA-AMSU which used AMSU-A satellite data, DA-MHS which used MHS satellite data, and DA-BOTH which used both AMSU-A and MHS satellite data. Model output verification was carried out using the observational data (AWS, AAWS, and ARG) and GPM-IMERG data. The results showed that the satellite data assimilation corrects the WRF model initial data, so as increasing the accuracy of rainfall predictions. The DA-BOTH scheme provided the best improvement with a final weighted performance score of 0.64.
Simulation of daily variation of precipitation during anomalously-wet dry season event over the western Maritime Continent
Authors: Yulihastin E , Suaydhi  , Satyawardhana H , Ihsan C N
Published: December 2021

Local seas play a significant role in causing anomalously wet of the dry season over the Indonesia Maritime Continent (10°S-8°N, 95-145°E). As a result, modeling the anomalously-wet dry season over Indonesia lead challenges due to several subregional processes over local seas could not be captured well in the regional climate model. This study explores subregions processes of sea-air interaction over the western Maritime Continent by simulating diurnal precipitation using Cubic Conformal Atmospheric Model (CCAM) with a spatial resolution of 32 km during the anomalously-wet dry season periods during May-to-September (MJJAS) 2020. The simulated results were confirmed by precipitation data from Tropical Rainfall Measuring Mission (TRMM) satellite observation. The results show anomalous circulation patterns induce anomalous regional precipitation over western MC is induced by anomalous circulation patterns over four keys of seas subregion, i.e., Indian Ocean, South China Sea, southern Sumatra (Lampung and Sunda strait), and the Java Sea. Furthermore, the anomalous circulation also modulates anomalous local circulation and enhances surface water vapor by an increased surface latent heat flux.
Coastal storm waves detection system design using Beaufort scale standardization and Sugianto wave forecasting method in Timbulsloko, Demak, Central Java, Indonesia
Authors: Ginanjar S , Adiningsih S , Fadlilah Y N , Wulandari S , Petrova C B , Ikhtiarino S
Published: December 2021

Storm is defined as a disturbance of the atmosphere marked by winds and usually by rain. Coastal storms must comprise a maritime component, such as waves, currents and/or water levels. Coastal storm detection is necessary so the number of casualties and losses caused by these events can be reduced. The method used in this system is the Sugianto wave forecasting method with standardization of coastal storms using the Beaufort scale. The purpose of this study is to built up an internet of things based system to observe coastal storm information and wave forecasting data from wind speed data that obtained in Timbulsloko, Demak, Central Java, Indonesia. The tidal data is processed using the Admiralty method. This system was built using Arduino Uno equipped with anemometer JL-FS2 to measure wind and waves parameters. The power source from 100 wp solar panels stored in a 40 Ah accumulator. Data from field instrument is stored to the IoT MAPID database using NodeMCU ESP8266. This system is placed in Timbulsloko, Demak. The results of field observation then validated using BMKG. This method could be applied in other location along the north coast of Java. The results of field observation showed an average wind speed 3.9848 m/s; significant wave height 0.4632 m; significant wave period 3.8641 s; wave energy 493.90 J/m2; wind energy 116.74 W/m2.
Analyzing Rainfall and Greenness Vegetation Level on Forest/Land Fire Area in Jambi and Central Kalimantan Provinces using Remote Sensing Data
Authors: Rahmi Khalifah Insan Nur , Prasasti Indah , Nugroho Jalu Tejo , Rokhis Khomaruddin M.
Published: December 2021

El-Nino, which occurred in 2019 in Indonesia, caused longer dry conditions than usual. Low rainfall and vegetation drought cause widespread forest/land fires. This study aims to know the relationship between drought conditions and forest/land fires from the parameters of rainfall and vegetation greenness level. The study located in Jambi and Central Kalimantan Provinces during the peak months of fires which is September 2019. To see fluctuations in the peak of fires, eight daily data were taken for this period. Extraction of rainfall information is derived from the Himawari-8 infrared band L1 image into L2 rainfall rate data. Vegetation greenness level information is derived from Terra/Aqua MODIS red and near-infrared band images into L2 Enhance Vegetation Index (EVI) data. Hotspot data comes from the images of Terra, Aqua MODIS, SNPP VIIRS, and NOAA20. Fire data was extracted from hotspot data and delineation of MODIS RGB image smoke. Rainfall fluctuation affects the number of forest/land fire hotspots. The decrease in rainfall was followed by an increase of hotspot numbers and vice versa. In Jambi Province, rainfall decreased in first to second period i.e. 40 to 0 mm was followed by an increase of hotspot number which dominated by high confidence level. In Central Kalimantan rainfall increased from third to fourth period i.e. 0 to 100-400 mm followed by the decreasing of hotspot number which dominated by medium confidence level. Meanwhile, the TKV variable had little effect on the number of hotspots but related with rainfall data. In Central Kalimantan Province, the driest TKV (0.1) on September 14-21, 2019, was influenced by low rainfall in the previous period which also has highest number of fire hotspots. In Jambi Province, the driest TKV happened on third period which also the result of lowest rainfall and highest number of fire hotspot in the previous period.
DINEOF reconstruction for creating long-term cloud-free sea surface temperature data records: A Case study in Lombok Strait, Indonesia
Authors: Andrawina Yochi Okta , Kismawardhani Ratu Almira , Rejeki Hasti Amrih
Published: December 2021

A long-term reliable sea surface temperature (SST) satellite data record is requisite resources for monitoring to understand climate variability. Creating a long-term data record especially for climate variability requires a combination of multiple satellite products. Consequently, missing data issues are inevitable. Hence, DINEOF (Data Interpolating Empirical Orthogonal Functions) has been applied to attain a complete and coherent multi-sensor SST data record with EOF-based technique by reconstructing the missing data. Unfortunately, the technique can lead to large discontinuities in the data reconstruction due to images depiction within long time series data. For that reason, filtering the temporal covariance matrix had been applied to reduce the spurious variability and more realistic reconstructions are obtained. However, this approach has not yet tested in tropical region with higher evaporation which cause incomplete satellite image coverage. Therefore, the objective of this research is to reconstruct SST of Lombok strait with data gaps up to 58.16% in one year. It is successfully reconstructed until the last iteration of 42 optimal EOF modes with the convergence achieved up to 0.9806×10-3, including previous set-aside data for internal cross-validation. The results highlight that the DINEOF method can effectively reconstruct SST data in Lombok Strait.
Application of hydrometeorological data to analyze water balance conditions in Bengkulu watershed
Authors: Faski G I S L , Purnama Ig L S , Suprayogi S
Published: December 2021

Abstrak

Water balance serves to determine hydrological conditions in a watershed, one of which is by analyzing the surplus (excess water) and deficit (water shortage) that occurs. Extreme surpluses or deficits can cause hydrometeorological disasters, such as floods or droughts. This study aims to calculate the monthly water balance using the Thornthwaite-Mather method to determine variations in the incidence of surplus and deficit months in all three sub-watersheds in Bengkulu Watershed, namely Rindu Hati, Susup, and Bengkulu Hilir sub-watershed. The data used are monthly hydrometeorological data for 2009-2018 (10 years) were divided into two periods of water balance based on land use data. Water balance period 1 (2009-2013) uses 2009 land use data, while period 2 (2014-2018) uses 2014 land use data. The results show that the surplus, deficit, runoff, and discharge in the three sub-watersheds in the Bengkulu watershed are affected by rainfall. In general, the deficit incidents in all three sub-watersheds occur almost every three years. The Rindu Hati and Susup sub-watersheds have the same variations of surplus and deficit month incidents, while the Bengkulu Hilir sub-watershed is different, both in periods 1 and 2. It is not only the rainfall that affects the variation in the events of surplus and deficit in all three sub-watersheds of the Bengkulu watershed, but also the amount of water holding capacity (WHC). Therefore, the application of hydrometeorological data to analyze the water balance conditions in the Bengkulu watershed provides information on climate impact on water resources and environmental impact on flows in the watershed.
Mapping of mangrove forest tree density using SENTINEL 2A satelit image in remained natural mangrove forest of Sumatra eastern coastal
Authors: Samsuri  , Zaitunah A , Meliani S , Syahputra O K , Budiharta S , Susilowati A , Rambe R , Ulfa M , Harahap M M , Arinah H , Elfiati D , Rangkuti A B , Sucipto T , Hakim L , Iswanto AH , Manurung H , Azhar I
Published: December 2021

The mangrove ecosystem in Forest Managemen Unit - VII (FMU) Sumatera Utara is a natural forest. FMU has not managed and utilizes mangrove forests optimally. It can open up opportunities for illegal loggers and trigger damage to these natural ecosystems. This condition requires prevention and mitigation so that severe damage to mangrove forests does not occur. This study aims to determine the relationship between vegetation index and mangrove density in the field and map the mangrove density distribution based on the image vegetation index value. The density distribution mapping was carried out by compiling a vegetation density estimator model NDVI, GNDVI, and TVI as independent variables. Correlation test and regression analysis between the vegetation index value (NDVI, GNDVI, and TVI) to the number of trees per unit area. The distribution model for the density of mangrove stands was chosen based on the coefficient of determination (R2). The study resulted from NDVI selected as the vegetation index used to map the distribution of mangrove density with a Pearson correlation coefficient (R) of 0.738. The selected model is Y = 2.48e2.8667x, which is an exponential equation with a coefficient of determination (R2) of 61.3%. Based on this model, the distribution of mangrove density has the lowest density reaching 400, and the highest density is 2,200 trees per hectare
The Bamboo Standing Stock Analysis in Karo Highland, North Sumatera - Indonesia
Authors: Samsuri  , Zaitunah A , Ahmad A G , Ramadhan M F
Published: December 2021

Bamboo is a type of grass with a high growth rate and can be a substitute for wood. The bamboo container is vast in range, so it is easy to cultivate. The number and distribution of Bamboo need to know how much Bamboo is available to meet market demand. This study aims to determine the standing stock of Bamboo in Karo districts. The method used is the multistage sampling method, which is to take samples on the map and continue with sampling in the field. Research shows that the dominant types are rope bamboo rope and green bamboo. The number of clumps found was between 600 and 1,600 per hectare. The average number of stems is 1,231 stems per ha. The most number clump bamboo ranges from 20 – 30 unit/ha; the most length bamboo section is between 25 – 30 cm.
Framework application of e-DNA metabarcoding as a variable to evaluate mangrove ecosystem
Authors: Basyuni M , Susilowati A , Susetya I E , Kajita T
Published: December 2021

Indonesia has the largest mangrove forests in the world, about 22.6% of the global total area. Mangrove forests are known to provide great benefits to the community as an ecosystem service and globally. Mangrove forests are threatened with loss due to anthropogenic and non-anthropogenic activities. Our previous research results show the important role of mangroves in the context of climate change for reducing greenhouse gas emissions and the diversity of terpenoids for salinity defense. The term metabarcoding of environmental DNA as a key indicator for evaluating mangrove ecosystems was introduced. This work proposed framework to study environmental DNA metabarcoding applications that can provide accurate information for evaluating mangrove ecosystems using an easy and fast method. The rich mangrove forest is getting disappeared without being recognized by its true diversity, function, and potential services to human beings. Application of conservation activities based on the species diversity in the mangrove ecosystem is almost impossible, because it is too difficult to study, in term of time and effort, despite the importance of acquiring the biodiversity information. However, DNA metabarcoding can be a “dream-like” tool and will contribute to obtain the species diversity data of the mangrove ecosystem, rapidly, globally, and massively.
Life cycle analysis (LCA) of the production of wood waste briquettes from Pinus spp.: Case study San Francisco Pichátaro, México.
Authors: Medina-Ríos E , Morales-Máximo M , López-Sosa L B , Aguilera-Mandujano A , Corral-Huacuz J C
Published: December 2021

This study shows a life cycle analysis (LCA) of the production of briquettes from wood residues of Pinus spp. in an indigenous community in Mexico. The analysis was carried out considering one Mega Joule (1MJ) of heat as a functional unit, including mainly environmental sustainability indicators, through the Life Cycle Analysis (LCA), and generating environmental impact scenarios for the functional unit by: a) comparing the carbon footprint using solar drying and firewood drying in the production of briquettes and (b) comparing the carbon footprint of the heat obtained by the briquettes from both previous systems with heat obtained from liquefied petroleum gas (LP gas) and firewood. The results show that solar-dried briquettes have the lowest carbon footprint, and more than 80% of the emissions are biogenic, making it an excellent choice as a clean and renewable energy source. In addition, the methane emissions from LP gas is much higher than emissions from briquettes, but the carbon monoxide (CO) and particulate matter (PM2.5) emissions are lower. This methodology applied to the production process will help decision-making in the creation of a micro-enterprise for the generation of solid biofuels in rural communities in Mexico.
Release of nickel ions and changes in surface microstructure of stainless steel archwire after immersion in tomato and orange juice
Authors: Lubis H F , Simamora G H
Published: December 2021

Stainless steel archwire is an important component of orthodontic appliances that have the potential to corrode. Consumption of foods and beverages with a low pH, such as fruit-based juices, can trigger the release of nickel ions in stainless steel archwire. This study aimed to determine the difference in the amount of nickel ions release and the surface microstructure of stainless steel archwire after immersed in tomato and orange juice. The sample used is stainless steel archwire with a diameter of 0.016 inches and length of 5 cm immersed in 15 ml of solution and then stored at 37°C in an incubator for 24 hours. The samples were divided into three groups (immersed in tomato juice,orange juice and artificial saliva), each group consisted of 9 samples. The solution was tested using an Inductively Coupled Plasma Mass Spectrometer (ICP-MS) to determine the number of nickel ions released. The archwire surface microstructure was tested using a Scanning Electron Microscope (SEM). The results showed that the average amount of nickel ion release in orange juice is more than tomato juice. There was a significant difference between the amount of nickel ion released and surface microstructure on stainless steel archwire after being immersed in tomato and orange juice.
The structure and diversity of vegetation treelets of tropical mountain forest on mount Bawakaraeng
Authors: Wiharto M , Wijaya M , Lodang H , Karim H
Published: December 2021

The study about the diversity and structure of treelet vegetation in three slope areas on the mountainous forest of mount Bawakaraeng, Regency of Gowa, Province of South Sulawesi had been done. There were 17 species of treelets throughout the study area, from 13 families and 16 genera. The Asteraceae family has the highest number of species with 3 species, followed by Fabaceae and Solanaceae which each has 2 species. Pteridium aquilinum, Chromolaena odorata, Breynia oblongifolia, and Pogostemon cablin are the species with the highest important value index. The number of treelet species ranges from 15-16. Treelet species were mostly found in the flat slope area. The Shannon-Wiener diversity index (H’) ranges from 2,033-2,161 and was found to be highest on steep slopes and lowest on flat slopes. The H’ has the same tendency as Simpson’s Diversity Index and Evenness Index of Pielou (E) and reverse relationship with Simpson’s Dominance Index.
Potential of papaya seeds as a heterogenous catalyst in biodiesel synthesis
Authors: Iriany  , Taslim  , Bani O , Purba H L M
Published: December 2021

A biomass based low-cost catalyst production has been attempted. This study evaluated papaya seeds as the catalyst precursor for biodiesel synthesis. Dried papaya seed powder was calcined at 500°C for 3 hours to produce papaya seed ash. Then, papaya seed ash was applied as catalyst for transesterification of palm oil and methanol. Catalyst load and reaction time was varied. Papaya seed ash was analyzed by SEM-EDX and biodiesel physical properties was analyzed according to the European standards (EN 14214). SEM-EDX results indicated that papaya seed ash contains a number of minerals such as K2O, MgO and CaO which can function as catalysts in biodiesel synthesis. The produced biodiesel also met European standards. Highest biodiesel yield of 95.6% was obtained for reaction temperature of 60°C, reaction time of 2 hours, catalyst load of 2%, methanol to oil ratio of 12:1. Preliminary research revealed that PSA may be applied as a catalyst in biodiesel synthesis.
Chemical content and fiber dimension of agarwood branches (Aquilaria malaccensis Lamk)
Authors: Batubara R , Wirjosentono B , Siregar A H , Harahap U , Lubis S M
Published: December 2021

Potential utilization of agarwood residues from twigs and branches is supported by its chemical content and fiber quality. This study aimed to analyze the chemical content and fiber quality of agarwood branches (Aquilaria malaccensis Lamk). Parameters measured in this study were the chemical contents including extractives, holocellulose, alpha cellulose and lignin based on Technical Association of Pulp and Paper Industries (TAPPI) standard. Fibers were obtained after pulping and bleaching to determine its quality. Chemical analysis of the primary branch of agarwood revealed the composition of extractives which were soluble in cold water (2.71%), hot water (3.31%), ethanol benzene (3.81%), and 1% NaOH (10.03%). The proportion of holocellulose, alpha cellulose and lignin in the primary branch was 78.17%, 52.70% and 26.68%, respectively. In addition, the chemical analysis of the secondary branch of agarwood also revealed the soluble extractives in cold water (2.96%), hot water (3.49%), ethanol benzene (4.14%), and 1% NaOH (14.42%). The proportion of holocellulose, alpha cellulose and lignin in the secondary branch was 75.61%, 50.65% and 26.77%. Hence, the fiber quality of agarwood branches was categorized into class II.
Oil palm (Elaeis guineensis Jacq.) micropropagation via somatic embryogenesis from female inflorescences explants
Authors: Panggabean N H , Basyuni M , Nurwahyuni I , Elimasni
Published: December 2021

The oil palm (Elaeis guineensis Jacq.) is a perennial woody oil crop in the Arecaceae family. Oil palm is well known for a long regeneration time, therefore, in vitro propagation received great enthusiasm from oil palm industries. Somatic embryogenesis (SE) has become one of the most promising clonal propagation techniques in recent times. This study was aimed to determine a protocol for micropropagation somatic embryogenesis from female inflorescences explants of oil palm. The explant used was obtained from the female inflorescences of the oil palm 2.5 years old Tenera variety. The basal media used was Y3 with the addition of the hormone 2,4-D with different concentrations (33,66,99 and 132 mg/L). Callus initiation was formed in 99 mg/L and 132 mg/L 2,4 – D concentration with the basal area and the percentage of callus formation is 31,25% and embryogenic callus was formed from primary callus development in the basal area of female florescence. Embryo somatic induction with cell suspension culture, because the liquid medium is more efficiently used in commercial-scale propagation. The embryogenic callus phase which is generally used in liquid medium is the nodular phase because it is still meristematic so that the potential for cell division is still high and can increase the percentage of embryogenic callus.
Isolation and genomic amplification of fish and shrimps from mangrove ecosystems in North Sumatra
Authors: Hairani H , Basyuni M , Susilowati A
Published: December 2021

Mangrove is a very typical ecosystem with a high level of diversity of flora and fauna. However, mangrove ecosystems are also one of the most vulnerable locations to extinction due to the high disturbances that occur. Some of the species that are susceptible to such disturbances are fish and shrimp. The use of barcode DNA is considered a fairly effective way to evaluate the condition of fish and shrimp populations in North Sumatra. Therefore, this study aims to obtain information on the success of kit methods and amplification patterns of barcoding marks 16S for fish and shrimp in mangrove ecosystems North Sumatra. The results showed that the kit extraction method produced a pattern of band that varied thick, thin and even smear. PCR amplification results with the 16S gene showed a good band pattern and indicated that the 16S primer used can detect fish and shrimp species that are visualized in the form of DNA bands.
Factors affecting revenue of fisherman in Asamjawa Raya Village, South Labuhanbatu Regency, North Sumatra
Authors: Desrita  , Rambey R , Aritonang B D , Leidonald R , Harahap Z A
Published: December 2021

South Labuhanbatu Regency has quite large water resources with the Barumun River which crosses Pasir Tuntung Village, Asamjawa Village, Kotapinang Village and Sisumut Village. This study aims to determine the factors that influence the income of fishermen in Asamjawa Village, South Labuhanbatu Regency. This research method is a descriptive method with a questionnaire tool and the data obtained were analyzed using SPSS software. The variables observed were fisherman’s income, fisherman’s education, length of time working as a fisherman, area of fishing location, daily working time, number of fishing gear and number of fisherman catches. The linear regression model of fishermen’s income in Asamjawa Village was obtained as follows: Y = -19.344,10 + 392.699,10 X1 - 5.024,53 X2 + 73.255,48 X3 + 16.349,29 X4 + 135.819,41 X5 + 12.465,72 X6. The regression analysis results obtained three variables that significantly affect the income of fishermen in Asamjawa Village, Torgamba District, South Labuhanbatu Regency. Where the variables that have a significant effect are the education variable, the number of catches, and daily working time.
The role of betel (Piper betle) leaf extract and glycerol on physical properties of bioplastic based on sago starch
Authors: Nasution H , Julianti E , Dalimunthe N F , Wulandari G
Published: December 2021

Starch-based bioplastic from sago is one of the potential sources in Indonesia. Since it is made from natural ingredients, it is easier to absorb water and susceptible to the activity of microorganisms. Betel leaf extract is one of natural antimicrobial agent that rich of tannin and flavonoid. This study aims to investigate physical properties and antimicrobial activity of sago (Metroxylon sp.) starch-based bioplastic. The betel leaf was extracted by using the ultrasonication method with ethanol as a solvent. Betel leaf concentrated extract is diluted using aquadest with a concentration of 2 g/100 mL (2%) to be applied as an antimicrobial agent in bioplastics. The compositions of glycerol were varied from 10-30% whereas betel leaf extract from 3-9%(v) in the manufacture of bioplastics. The results show that the highest density of 1.5 g/cm3 was achieved at the composition of glycerol and betel leaf extract, respectively, 30%(v) and 9%(v). The highest water absorption percentage was shown by sample with 30%(v) glycerol without addition of betel leaf extract, that was 83.31%. The antibacterial activity showed that the addition of betel leaf extract to bioplastics was able to inhibit the activity of bacteria (Bacillus cereus). The best inhibition were shown in bioplastics with a variation of 20%(v) glycerol and 9%(v) betel leaf extract addition. However, all variation did not show their inhibition with fungal activity (Aspergillus niger).
Distribution and association pattern of pasak bumi (Eurycoma longifolia) in Batang Lubu Sutam District, Padang Lawas, North Sumatra
Authors: Susilowati A , Rachmat H H , Yulita K S , Elfiati D , Ginting I M
Published: December 2021

Pasak bumi (Eurycoma longifolia) is a medicinal plant with various benefits and has long been used to cure various diseases such as cancer, gingivitis, intestinal worms, and anti-inflammatory anti-malarial, and tonic after childbirth. The root has high economic value leading to unsustainable harvest and drastic population decline. As initial data in conservation activities, information regarding the association of pasak bumi in Batang Lubu Sutam natural forest has not been obtained. Therefore, this research was conducted to determine the pasak bumi distribution and its association within their natural habitat in Batang Lubu Sutam forest. The study was conducted by using the vegetation analysis method using a plotted path determined by purposive sampling. Data analysis was performed by calculating association indices, including the Ochiai index (Oi), Dice index (Di), and Jackard index (Ji). The results showed that pasak bumi were found in the seedling and sapling stage in the research location and form a degree of association with several plants. The species that formed the highest degree of association with the pasak bumi at both levels of regeneration wasShorea leprosulawith an Ochiai index value of 0.85 at the seedling level and 0.94 at the sapling level.
Analysis of vegetation diversity at urban forest Balai Wilayah Sungai (BWS) II Medan
Authors: Arinah H , Sutiawan J
Published: December 2021

The urban forest is part of the public green open space (RTH) formed from tree vegetation that affects temperature and humidity and reduces wind speed to provide comfort for residents in the vicinity. One of the urban forests in Medan is the Balai Wilayah Sungai (BWS) II Medan. Therefore, vegetation density has an influence on temperature and which affects the quality of urban forests. This study aimed to identify the structure and composition of the BWS II Medan urban forest vegetation. The vegetation analysis method used in this study is a combination method between the path method and the plotline method. The vegetation data that has been obtained is then processed to obtain the Important Value Index (IVI) and the Plant Species Diversity Index (H’). The results showed that the woody plants found in the urban forest of BWS II Medan were 20 species with the composition of seedlings of four species (26 individuals), saplings of twelve species (49 individuals), poles of eleven species (39 individuals) and trees of ten species (141 individuals). The species that dominates at the tree level is Trembesi (Samanea saman), with an IVI value of 118.16%. Meanwhile, the dominant plant species at the seedling, sapling, and pole levels were Mahoni (Swietenia mahagoni), with IVI values of 78.67%, 55.73%, and 103.62, respectively. Therefore, the level of diversity in the BWS II Medan Urban Forest for saplings is classified as moderate, while seedlings, poles, and trees are classified as low.
The analysis of landslide vulnerability level distribution in the Labuhanbatu Utara Regency, North Sumatera Province, Indonesia
Authors: Thoha A S , Slamet B , Harahap M M , Sari T Y , Hulu D L N
Published: December 2021

Forest degradation can increase the level of disaster risk, particularly landslides. The impact of landslides, especially in Labuhanbatu Utara Regency, North Sumatera Province, socio-economic, physical and environmental losses that are directly perceived by the community in the disaster site. The study objective was to analyze the distribution of landslide vulnerability levels in the Labuhanbatu Utara Regency. The spatial distribution of landslide vulnerability level used spatial modeling with the Storie Index method with four variables, including rainfall, slope, soil type, and land cover type. The spatial distribution of landslide vulnerability level was mostly at a very low – low level with a percentage of 57.6% of the area of Labuhanbatu Utara Regency. Areas that occupied high – very high of landslide vulnerability level with the largest area were in three districts, including Na IX-X, Aek Natas, and Kualuh Selatan. Landslide prone areas are generally located on plantation and agricultural land use and also distribute on steep slopes. Various parties need to reorganize community activities in areas of high – very high landslide vulnerability to reduce disaster risk.