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Climate Comfort in Nature-Based Tourism at Tropical Region
Full text linkThis research reveals visitor perceptions of climate comfort in nature-based tourism areas in Indonesia. We combined a survey and modeling to calculate the comfort score based on Tourism Climate Index (TCI) and Holiday Climate Index (HCI) in three tourism sites of Ecopark Ancol, Bogor Botanical Garden, and Cibodas Botanical Garden. During the survey, we collected data on climate comfort perceptions and the role of the weather on the comfort. Totally, 793 respondents of tourism visitors participated in the study. Our results showed that almost all of visitors (>95%) stated that the weather affected the climate comfort. Interestingly, the weather condition did not influence on the decisions where the tourism site to visit. The level of perceived climate comfort for the sites were neutral (Ecopark, 57.3%), and comfortable (Bogor Botanical Garden, 60%; Cibodas Botanical Garden, 78.4%). Then by modeling we obtained the best method to calculate the comfort based on the following index: (i) TCI with Physiological Equivalent Temperature (PET) Tianjin for Ecopark (57.2), (ii) HCI for Bogor Botanical Garden (59), and (iii) HCI with PET Tianjin for Cibodas Botanical Garden (77.6). Further, perception on climate comfort was significantly difference among sex, age, and education level of the visitors. In warmer environmental condition, the older people and women feel more comfortable. Our finding revealed that topography was weak correlated with comfort perception. By understanding visitor perceptions, strategies and appropriate actions can be developed to increase comfort in the nature-based tourism industry
Long-term Monthly Discharge Prediction for Cimanuk Watershed
Full text linkAlthough streamflow data is important for water resource planning, it’s long-term availability for Indonesian rivers is limited. One factor could be identified for example lack of observation. Here, we presented observation-based modeling to predict long-term discharge data for Cimanuk watershed in Indonesia. The watershed is categorized as one of the critical watersheds, meanwhile it supports to more than one million people. A well-known hydrological model called Soil and Water Assessment Tools (SWAT) was used to predict monthly discharge. The model was fed with monthly climate data, topography, land use and soil characteristics. We calibrated the model with the observed data from 1974 to 1994 (20 years). Our results showed that the model was a good performance in estimating monthly discharge as indicated by three statistical metrics used. Based on statistical evaluation, the calibration resulted a low percent bias (3.20%), strong correlation (0.73), and high Kling-Gupta Efficiency (0.78). Further, we did a sensitivity analysis for the model, and we found that hydrological response unit was the most influential parameters for the Cimanuk watershed. A long-term discharge data indicated a monsoonal pattern for this watershed
Water Demand Analysis of Sugarcane Based on Crop Simulation Model (Case Study: Kediri Regency, East Java)
Full text linkSugarcane productivity is naturally affected by climate variables and limited by the water availability. This study simulated a water balance model to estimate sugarcane water requirement and to estimate the best planting time as well based on its optimum productivity in Kediri Regency. Water requirement was estimated by water loss of evapotranspiration following FAO No. 24, while the productivity was based on mid-maturing sugarcane growth and development. Sugarcane rainfed area in Kediri Regency needs approximately 26-128 mm water per month based on its loss by evapotranspiration. The value varied due to the growth phase. More than 60% water was used in vegetative phase for developing buds and stem elongation of about 3-9 months after planting. The highest sugarcane productivity was obtained in July-September as the best planting time shown by simulation. Moreover, water deficiency during mid-season of sugarcane growth could decrease productivity by a significant amount. The work presented here could be used as a tool to help decision makers for irrigation management and select the best planting date.
Estimation of Indonesian Peat Forest Carbon Emissions based on Soil Moisture Active Passive (SMAP) Satellite Image
Full text linkCalculation of carbon emission in tropical peatland forest still unsolved problem. In this paper, we propose a method to calculate carbon emission by using Soil Moisture Active Passive (SMAP) satellite. The SMAP images on January 2018 enhanced 1.3 radiometer Global Daily 9 km, EASE grid overlayed with peat map. The water table mapping obtained by using empirical relation between soil moisture and water table in January 2018 shows a pattern according to some observation. The carbon emission map on January 2018 shows the average is about 280 gC km-2
Determination of Extreme Hydrological Index using HBV Model Simulation Results (Case Study : Upper Ciliwung Watershed)
Full text linkThe study of climate change on hydrological response is a crucial as climate change impact will drive the change in hydrological regimes of river. Upper Ciliwung watershed is one of the critical rivers in Java Island, which has been affected by climate change. This study aims to: (i) simulate the discharge flow using the Hydrologiska Byrans Vattenbalansavdelning (HBV) model; (ii) simulate future flow using three general circulation models (GCM) namely Commonwealth Scientific and Industrial Research Organisation (CSIRO) Mk.3.6.0, Model for Interdisciplinary Research on Climate version 5 (MIROC5), and Geophysical Fluid Dynamics Laboratory-Coupled Model generation 3 (GFDL-CM3); (iii) determine the changes of extreme hydrological index during historical period (2001-2015) and projected period (2031-2045). The historical year simulation and projections are used to determine eight hydrologic extreme indices for high flow and low flow. We calibrated the HBV model for two years (2001-2002) and validated it for two years (2003-2004). Our model performed well in discharge simulation as shown by the NSE values (0.66 for calibration and validation). Then we calculated the indices for each period used (historical and projected). To show the changes in hydrological regimes, we compare the indices between two periods. Changes in the index of the two periods tend to decrease in value on the index parameters that characterize the minimum extreme events. Hence, that it is possible in the projected period there will be extreme hydrological events in the form of drought
Surface Temperature and Heat Fluxes: Comparison between Natural Forest and Oil Palm Plantation in Jambi Province Using Surface Energy Balance Algorithm for Land (SEBAL)
Full text linkOne of the leading commodities that has contributed a lot of income for Indonesia is oil palm. Oil palm plantations in Jambi are widespread, affecting the energy balance and surface temperature. This study aims to compare surface temperature and heat fluxes of oil palm plantation with different ages, how is the difference between forest and oil palm plantation, and to analyze the effect of oil palm planting on micro-climate change in Jambi. Using the Surface Energy Balance Algorithm for Land (SEBAL), it was found that in Jambi, young oil palm (2 years old) had higher surface temperatures of 2oC compared with adult oil palm (19 years old). While the surface temperature of the adult oil palm plant is slightly higher than natural forest that is 0.5oC. The increase of the age of oil palm followed by the increase of plant height (h), Canopy Cover (CC), and surface roughness which resulted in the increase of NDVI value and the cooling effect around the plantation so that the surface temperature (Ts) decreased as indicated by equation TS = 27.00 - 0.1581h - 0.0317CC and NDVI = 0.1335 + 0.00892h + 0.00096CC. The sensible heat flux (H) is affected by surface temperature, roughness length, friction velocity, and aerodynamic resistance of the plant. The highest H value is in the oil palm plantation near Brimob which is 282 W/m2. Latent heat flux (LE) is the remainder of the net radiation minus the flux of the soil and the flux feels. The highest LE value is in the oil palm plantation of Pompa Air Village which is 710 W/m2. Substantially ground heat flux (G) is affected by net radiation, NDVI, surface temperature, and albedo. The highest value of G is in PT Pisifera Persada oil palm plantation of 98 W/m2.Keywords: NDVI, net radiation, sensible heat flux, latent heat flux, Canopy Cove
The Use of Reflective Mulch in Soybean-Oil Palm Intercropping System
Full text linkDemand for soybean is increasing nowadays as it provides a high nutrition food at affordable price. To fulfill the demand, an intercropping system of soybean-oil palm may increase the production of soybean. However, shading by the oil palm canopy would reduce the amount of radiation reaching the soil surface. Theoritically, application of reflective mulches may increase the amount of solar radiation intercepted by the shaded plants, hence it gives a positive effect for plant growth. The study aimed to analyze the effect of an increased radiation transmission with reflective mulch on the growth and development of soybean under an intercropping system with 4-year olds oil palm. The experiments were carried out on PT. Perkebunan Nusantara VIII located in Cimarga District, Lebak Regency, from March to June 2018. There were three treatments based on mulch application, namely soil without mulch (R0), soil with black silver plastic mulch (R1), and soil with dry palm oil leaf mulch (R2). The results showed that a canopy of 4-year-olds oil palm transmitted around 42% of an incoming radiation. The use of mulch as radiation reflector has a positive effect on an increased interception of solar radiation and potential productivity. Under R1 and R2 treatments, intercepted radiation was 25% and 15% larger than that of R0. In addition, mulch increased radiation use efficiency (RUE) by 2.3 times under R1 (1.6 g/MJ) and 1.7 times under R2 (1.2 g/MJ). The potency of productivity also increased (1.48 and 1.42 times higher under R1 and R2, respectively). The finding confirmed that mulch application did not affect the plant development in any treatment. Furthermore, we suggest that an intercropping system of soybean and 4-year-olds oil palm may be applied to increase the soybean production in Indonesia
Trend of Extreme Precipitation over Sumatera Island for 1981-2010
Full text linkExtreme climate events have significant impacts on various sectors such as agriculture, ecosystem, health and energy. The issue would lead to economic losses as well as social problems. This study aims to investigate the trend of extreme precipitation in Sumatera Island based on observed data during 30-year period, 1981–2010. There are ten indices of climate extreme as defined by ETCCDMI, which were tested in this study, including PRCPTOT, SDII, CDD, CWD, R10, R50, R95p, R99p, Rx1day and Rx5day. Then, the trend was analyzed based on the Mann-Kendall statistic, performed on the time series of precipitation data. The result shows that there was positive trend of extreme precipitation found in most stations over Sumatera, either statistically significant or insignificant. In each extreme precipitation indices, the number of observed stations indicating the insignificant change is higher than the significant one. This research also found that some indices including SDII, Rx1day, R50, R95p and R99p, showed a significantly-positive trend followed by a higher intensity of wetter and heavier events of extreme precipitation over Sumatera. On the other hand, the wet spell (CWD) index shows a negative trend (α=0.05)
Potential of Green Leafhopper Attack (Empoasca sp.) in Tea Plantation Based on Climate Change Scenarios
Full text linkPest growth is closely related to the climate conditions. This study aimed to analyze the impact of climate variability and climate change on the potential attack of green leafhopper (Empoasca sp.) on tea plantations at PTPN VIII Gunung Mas. The analysis was carried out to calculate the value of Ecoclimatic Index (EI) based on the functions of the compare years and the compare location in CLIMEX model. Pest suitability in the future was projected using RCP 4.5 and 8.5 climate scenarios, which were derived from MIROC 5 and CCSM 4 climate model outputs. The result indicated that Gunung Mas Tea Plantation was suitable for Empoasca sp. growth. The EI value (58) in the baseline year (2012-2017) confirmed the suitability. Climate variability influences the suitability for Empoasca sp. growth. During El-Niño, the EI value decrease substantially (~26%). On the other hand, the EI value is projected to slightly increase in the future for both climate scenarios
Analysis of Regional Water Availability for Domestic Water Demand (Case Study: Malang Regency)
Full text linkThe fulfillment of water demands needs to consider climate variability impacts on water availability. A seasonal change from wet to dry may have a negative impact on water availability leading to water scarcity for domestic purposes. Therefore, information on water condition until sub-district level is important. We did water balance approach to analyze water condition especially during dry season in Malang district, East Java for period 2007-2016. Our results showed that several sub-districts faced a serious problem with water deficit condition. During dry season, an increased domestic water demand was not supported by water availability, which caused some villages could not provide basic water for domestic purposes. Further, the research may contribute to support mitigation and adaptation strategy for climate extreme in the region