Claim Missing Document
Check
Articles

Found 12 Documents
Search

PREDIKSI DEBIT JANGKA PANJANG UNTUK SUNGAI BENGAWAN SOLO Widyastuti, Marliana Tri; Taufik, Muh; Santikayasa, I Putu
Jurnal Geografi : Media Informasi Pengembangan dan Profesi Kegeografian Vol 15, No 2 (2018): July 2018
Publisher : Universitas Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15294/jg.v15i2.15387

Abstract

Sungai Bengawan Solo merupakan sungai terpanjang di Pulau Jawa dimana daerah alirannya telah diklasifikasikan sebagai salah satu Daerah Aliran Sungai (DAS) kritis di Indonesia. Penelitian ini mencoba memprediksi debit jangka panjang Sungai Bengawan Solo, dengan tujuan khusus untuk (i) melakukan kalibrasi dan validasi model Soil and Water Assessment Tool (SWAT) dalam mengestimasi debit skala bulanan, dan (ii) mensimulasikan debit bulanan untuk periode 1901 – 2016. Penelitian ini, model SWAT menggunakan input data iklim bulanan, penggunaan lahan, dan karakteristik tanah. Berdasarkan hasil evaluasi, secara statistik model mampu mensimulasikan debit bulanan dengan baik ditunjukkan dengan nilai yang rendah dari percent bias (PBIAS: -2.30%) dan RMSE standard ratio (RSR: 0.44), dan nilai Kling-Gupta Efficiency yang tinggi (KGE: 0.87). Berdasarkan debit hasil simulasi, kami menemukan bahwa debit maksimum terjadi pada bulan Maret, sedangkan debit minimum terjadi pada bulan Agustus. Karakteristik debit bulanan Sungai Bengawan Solo untuk aliran tinggi (Q5) sebesar 198.00 mm/bulan, sedangkan aliran rendah (Q90) sebesar 13.00 mm/bulan. Informasi tentang karakteristik hidrologi sungai sangat penting untuk pengelolaan DAS terpadu, terutama untuk mengantisipasi iklim yang sering berubah.
KERAGAMAN PRODUKTIVITAS KOMODITAS KEDELAI PADA BERBAGAI SKENARIO PERUBAHAN IKLIM MENGGUNAKAN MODEL IKLIM DAN PERTANIAN . Perdinan; I Putu Santikayasa
Jurnal Ilmu Pertanian Indonesia Vol. 11 No. 2 (2006): Jurnal Ilmu Pertanian Indonesia
Publisher : Institut Pertanian Bogor

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1334.279 KB)

Abstract

The need of soybean in Indonesia grows from time to time. Now, Indonesia imports at about 1,1 milion ton/ha yearly. This condition indicates that the need of soybean in Indonesia can be a serious problem of agricultural sector in the future. Furthermore, the climate change issue as a result of human activity used a large amount of fosil fuel will derive a new problem for agricultural sector which requires a better strategy of anticipation. This point out the important of information in order to estimate the potential of soybean's yield in Indoensia in the future. In general, this research is designed to identify the evidence of climate change and to learn the impact of the climate change scenarios on the future of soybean's yield in Bandung district. For this purpose, literature study and analysis of global circulation model (data) data are applied for identifying the occurrence of climate change. Then, the impact analysis of these scenarios on soybean's yield is conducted by using climate and agricultural simulation model, which consist of statistic and mechanistic models. Analysis of the earth surface mean temperature shows the increasing of global air temperature has been started since 19's century with the occurence of increasing temperature from about -0.4 °C to about 0.1 °C in the year of 1940's. Then, the occurence of climate change in Indonesia can be identified using monthly rainfall data for a certain period. Previous study, which has been conducted by Kaimuddin (2000) shows the changing of rainfall pattern in Indonesia. Additionally, analysis on Global Circulation Model (GCM) data for various climate change scenarios reveal the evidence of rainfall and temperature changing variability in percentage for each model in year 2020, 2050 and 2080. The highest value of A2 scenario in come from NIESS, meanwhile for B2 scenario is GFDL. Then, the minimum value is mostly gained from ECHAM model. Moreover, the result of simulation using maximum and minimum value from those scenario for year 2020 decrease in almost of the whole area of Bandung.
Water Allocation Based on Economic Criteria Using Aquarius Model (A Case Study in Ambang-Brantas subbasin, Indonesia) I Putu Santikayasa; . Agis; Siti Maesaroh
Agromet Vol. 31 No. 2 (2017): DECEMBER 2017
Publisher : PERHIMPI (Indonesian Association of Agricultural Meteorology)

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1427.684 KB) | DOI: 10.29244/j.agromet.31.2.89-102

Abstract

The use of economic approach on water allocation are inclusively becoming integrated on water resource management. Competing among water users is expected to escalate due to increasing water demand despite of limited water availability. This research used economic approach aiming to optimize water allocation in Ambang-Brantas subbasin, Malang, and to calculate the total benefit for different sectors of allocated water. We distinguished two scenarios (2012–2015 and 2016–2035) to reflect the existing and the future water allocation. We modelled the water allocation with the Aquarious application. In this subbasin, three main sectors of water users were identified i.e. domestic, agriculture, and industries. The results showed that the agricultural sector was the highest water demand compared to other sectors. This finding was consistent both monthly and annually. Our findings revealed that industries sector show the maximum benefit per unit water used. Based on the scenario, either a decreasing water availability by 10% or an increasing water demand by 10% will decline the total benefit by 44%. If we increase the scenario to 20% it will reduce the total benefit until 71%. This modelling exercise using Aquarius application shows that the model is a promising tool for water resource management with integration of economic approach.
Influence of Land Use and Rainfall on Carbon Stock Dynamics for Oil Palm and Rubber Oktanindita Priambodo; Hariyadi; Suwarto; I Putu Santikayasa
Agromet Vol. 34 No. 2 (2020): DECEMBER 2020
Publisher : PERHIMPI (Indonesian Association of Agricultural Meteorology)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29244/j.agromet.34.2.121-128

Abstract

The expansion of agricultural commodities including oil palm plantations potentially causes an increase of greenhouse gas emissions by amplifying carbon dioxide (CO2) in the atmosphere. In the long term, this amplification will alter climate change. However, oil palm also has the potency to reduce greenhouse gas emissions by absorbing CO2 through photosynthesis. This study aims to determine the carbon stock that can be absorbed by oil palm and rubber plants, and to determine the relationship of rainfall with carbon stock in oil palm plants. The study used satellite image data based on Landsat and combined with rainfall data from near Perbaungan District, North Sumatra. Three Landsat data (acquisition date: (i) 12 February 2000, (ii) 8 March 2009, and (iii) 11 August 2019) were processed to estimate carbon stock. The procedure for estimating carbon stock was as follows: determining the sample and digitizing the sampling points, converting the digital value of the numbers into the spectral spectrum, calculating the albedo values, calculating the long-wave and short-wave radiations, computing biomass, and the absorbed carbon stock. The results showed that the carbon stock in oil palm was greater than that of rubber plants as oil palm has a greater biomass. The greater the plant biomass, the bigger the carbon stock absorbed. Further, the findings revealed that rainfall in dry season has a contribution to carbon stock in oil palm and rubber. The higher the total rainfall during dry season will increase the absorbed carbon stocks.
Pemodelan Dinamika CO2 Pada Tanaman Kelapa Sawit Meriana Ina Kii; Tania June; I Putu Santikayasa
Agromet Vol. 34 No. 1 (2020): JUNE 2020
Publisher : PERHIMPI (Indonesian Association of Agricultural Meteorology)

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (554.343 KB) | DOI: 10.29244/j.agromet.34.1.42-54

Abstract

Oil palm plantation has a high potency to absorb carbon. Limited observed data and expensive instrumentations to measure the absorbed carbon have caused an inaccurate estimation of carbon storage from oil palm. The objectives of this research were to develop a CO2 absorption model, and to calculate the carbon cycle based on climate factors and plant age. CO2 absorption was derived from gross primary production (GPP) and net primary production (NPP), which were ​​based on solar radiation. From NPP we derived net ecosystem exchange (NEE) by calculating the difference between NPP and soil respiration. Our results showed that age of oil palm has influenced the CO2 absorption from 9.8 (1 year) to 117 tons ha-1 year-1 (19 years), with average of 86.5 tons ha-1 year-1 (over 25-year life cycle). We validated our NPP model with biomass that indicated a very good performance of the model with R2 0.95 and RMSE 1.81. Meanwhile, the performance of NEE model was slightly lower (R2 0.71 and 0.72, for wet and dry conditions), but the model had a similar pattern with the measured NEE. Based on the model performance, the findings imply that the model is useful to estimate CO2 absorption, where there is no eddy covariance measurement. This research suggests that carbon modeling will contribute to global terrestrial carbon modeling.
The Use of Dam Environmental Vulnerability Index (DEVI) for Assessing Vulnerability of Bengawan Solo Watershed, Indonesia RR Mashita Fauzia Hannum; I Putu Santikayasa; Muh. Taufik
Agromet Vol. 34 No. 2 (2020): DECEMBER 2020
Publisher : PERHIMPI (Indonesian Association of Agricultural Meteorology)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29244/j.agromet.34.2.110-120

Abstract

Bengawan Solo is the longest river in Java, but current conditions show that its watershed is in a critical condition. Deforestation was very intensive in the last three decades that contributed to degradation of the watershed. Other factor contributing to the degradation is dam construction. However, our knowledge on the impact of dam construction on the environment and its vulnerability is poorly understood. Here, we assessed vulnerability of the watershed based on physical properties such as existing dams, morpho-dynamic activities, and deforested area. The study aims to identify the vulnerability of the Bengawan Solo watershed based on dam environmental vulnerability index (DEVI) approach, and to analyse the dominant variable contributing to DEVI. For calculating DEVI, several data were needed including land cover, rainfall, stream water stage, soil type, stream network, and dams. The results showed that Bengawan Solo watershed had moderate to high vulnerability (60%). Moderate level was identified for Madiun and Wonogiri sub-watershed, while high level was in Cepu and Babat sub-watershed. Our findings revealed that morpho-dynamic activities as represented by sediment rate and stream water stage had contributed to the high DEVI value as in Cepu and Babat sub-watershed. Further, influence of dams in this research was not dominant implying that any improvement to the DEVI approach remains research challenges. The improvement of the approach is expected to better identify the impact of dam construction on environment, situated in other regions than Amazon, where it was firstly developed.
The Use of Weather Research and Forecasting Model to Predict Rainfall in Tropical Peatland: 1. Model Parameterization Alfi Rizky Sanusi; Muh Taufik; I Putu Santikayasa
Agromet Vol. 35 No. 1 (2021): JUNE 2021
Publisher : PERHIMPI (Indonesian Association of Agricultural Meteorology)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29244/j.agromet.35.1.49-59

Abstract

Rainfall dynamics play a vital role in tropical peatland by providing sufficient water to keep peat moist throughout the year. Therefore, information of rainfall data either historical or forecasting data has risen in recent decades especially for an alert system of fire. Here the Weather and Research Forecasting (WRF) model may act as a tool to provide forecasting weather data. This study aims to do parameterization on WRF parameters for peatland in Sumatra, and to perform bias correction on the WRF’s rainfall output with observed data. We performed stepwise calibration to choose the best five physical schemes of WRF for use in the study area. The output WRF’s rainfall was bias corrected by spatially observed rainfall data for 2019 at day resolution. Our results showed the following schemes namely (i) Eta scheme for cloud microphysical parameters; (ii) GD scheme for cumulus cloud parameters, (iii) MYJ scheme for planetary boundary layer parameters; (iv) RRTM for longwave radiation; and (v) New Goddard schemes for shortwave radiation are best combination for being used to predict rainfall in maritime continent. The spatially interpolated observed rainfall with the Inverse Distance Weighting (IDW) was outperformed for calibration process of WRF’s rainfall as shown by statistical indicators used in this study. Further, the findings have contributed to advance knowledge of rainfall forecasting in maritime continent, particularly in providing data to support the development of fire danger rating system for Indonesian peatland.
Drought Events in Western Part of Timor Island Indonesia Flegor Hermes Sabuna; Rini Hidayati; I Putu Santikayasa; Muh Taufik
Agromet Vol. 36 No. 1 (2022): JUNE 2022
Publisher : PERHIMPI (Indonesian Association of Agricultural Meteorology)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29244/j.agromet.36.1.11-20

Abstract

Drought is a below-averaged condition of water availability, which has detrimental impacts on many sectors. Many studies have been performed on drought analysis in Indonesia, yet knowledge about drought in western Timor is still limited. This research carried out a historical meteorological drought analysis based on a 3-month Standardized Precipitation Index (SPI) and Standardized Precipitation Evapotranspiration Index (SPEI) using global climate data for 1989-2018. The index value was then categorized into three groups: moderate, severe, and extreme. We assessed: (i) the influence of El Niño phenomena to drought events, (ii) drought class frequency, and (iii) drought trend. Based on historical data, western Timor had a monsoonal pattern with dominant dry period, which occurred in April to November. The results showed that the drought events were mostly influenced by El Niño. Seasonally, El Niño not only increased the drought frequency in July-August (JJA) season, but also in other seasons. In El Niño year of 2015, drought covered most parts of study area during September-November (SON) season, especially in the western part. Dry conditions increased in June, reached maximum in September-November, and decreased in December. Other findings show that an extreme drought consistently had a downtrend, while the moderate drought had upward trends. Spatiotemporal drought analysis using SPI and SPEI showed similar patterns, SPEI detected a higher frequency of drought classes compared to SPI. This study suggests that knowledge on drought-related El Niño will benefit on drought mitigation action in the future.
Identifikasi Lokasi Potensial Panen Air Hujan Menggunakan Indeks Kesesuaian Embung dan Sistem Informasi Geografi di Provinsi Jawa Timur Indonesia: Identification of Locations for Potential Rainwater Harvesting Using the Conformity Index of Embankments and Geographic Information Systems in East Java Province, Indonesia I Putu Santikayasa; Mauludiyyatus Syarifah; Muh Taufik
Jurnal Teknik Sipil dan Lingkungan Vol. 6 No. 3: Desember 2021
Publisher : Departemen Teknik Sipil dan Lingkungan, IPB University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29244/jsil.6.3.187-204

Abstract

Increasing population has an impact on increasing food supply to fulfil the requirement of the community. Increasing in food supply is able to be achieved by increasing the agricultural productive area. Low-water agricultural technology is one of technology can be applied in the development of agricultural areas with sufficient water availability. But on the other hand, water harvesting technology using pond is one approach in the development of agricultural land in dry areas. This study uses a geographic information system (GIS) approach to identify areas that have high potential for the development of water harvesting ponds in East Java Province, Indonesia. GIS approaches is used for spatial analysis in calculating the area potential index for the ponds deveopment based on climate, physical surface and vegetation indicators. This index is calculated based on indicators, each of which is obtained from the surface parameter data. The results of the study show that the East Java Province is categorized as the "very suitable" and "appropriate" areas on water harvesting ponds suitability by 55% and 23%, respectively. This results show that the potential of the East Java area for developing water harvesting pond is very high about 78% compared with the entire region. On the other hand, locations that is categorized as "not suitable" and "very inappropriate" are about 8.7% and 9.2% compared with total area of ​​East Java Province. Iit can be concluded that climate, physical surface and vegetation indicators are very important in determining the locations of water harvesting ponds development in East Java Province.
Analisis Indeks Pencemaran Airtanah di DKI Jakarta dengan Interpolasi Spasial: Analysis of Groundwater Pollution Index in DKI Jakarta using Spatial Interpolation Dimas Ardi Prasetya; I Putu Santikayasa; Iqbal Hanun Azizi
Jurnal Teknik Sipil dan Lingkungan Vol. 6 No. 3: Desember 2021
Publisher : Departemen Teknik Sipil dan Lingkungan, IPB University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29244/jsil.6.3.177-186

Abstract

Everyone needs water to his life and his activity. Groundwater pollution is one of the problems in Indonesia. The increasing number of the show an increase water needs. They were filled with groundwater needs. There has been decreasing groundwater that is occupied in quantity and quality. The research was done in Jakarta, consisting of 42 sub-district. Research takes into account the condition of the dry season. Uses index research quality of groundwater pollution. Monitoring parameter groundwater consisting of physics, chemical and biology paramater. The research consists of determining the pollution index in Jakarta, analysis of groundwater pollution, and predicted entanglement with an index pollution population density. The research uses spatial interpolation to determine locations. Pollution index calculation used calculation storet. The measurement results in the rate used in the analysis index groundwater pollution. The research results obtained index value has increased pollution are on the north and central of Jakarta. The research results obtained East Jakarta having the condition geology that porous. The value of the groundwater pollution index was in north Jakarta. The results of the study indicated by a map pollution index the quality of groundwater during three periods. Index pollution in Jakarta consisting of pollution until the same as the quality standard. Research shows the absence of correlation with the population with the pollution groundwater quality.