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Volume 70, Issue 4
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Juan C. GARCIA M, Takashi MACHIMURA, Takanori MATSUI, Tatsuya MIYAUCHI2014 Volume 70 Issue 4 Pages 171-185
Published: 2014
Released on J-STAGE: December 10, 2014
JOURNAL FREE ACCESSIt is known that bioethanol is an alternative for fossil fuels for reducing GHG emissions, and agro-residues offer potentially significant advantages over other feedstock because of reduced conflict with food production. In this study, which aims to assess biomass energy potential and GHG reduction effects in Ecuador in the present and under climate change, NPP predicted by an ecosystem process model was utilized with a life-cycle GHG assessment and optimization of a biomass energy system. First, the NPP of rice, banana, sugarcane, and corn in the present and under climate change was predicted by Biome-BGC. Next, productivity of each of the four crops was formulated by NPP using government crop statistics and the model-predicted NPP, where the difference in technological and management standards among provinces was considered. Then, based on estimated crop production and geographical distribution of croplands and consumption, a nation-wide bioethanol production plan was proposed. Applying a life-cycle assessment to account for GHGs, crop selection for feedstock and product-delivery allocation, were optimized to maximize GHG reduction. Under the most-severe climate change case, total GHG emission reduction was decreased by 7% of the present condition, caused by decreased crop productivity, longer feedstock transportation, and the use of less-efficient crops.View full abstractDownload PDF (3287K) -
Eiji KANDA, Hiromitsu KANNO, Sayuri OKUBO, Teruhisa SHIMADA, Ryuhei YO ...2014 Volume 70 Issue 4 Pages 187-198
Published: 2014
Released on J-STAGE: December 10, 2014
JOURNAL FREE ACCESSWe analyzed the impact of climate change due to global warming on the risk of cool summer damage to paddy rice in the Tohoku region of Japan. We downscaled the atmospheric general circulation model of the Meteorological Research Institute (MRI AGCM) to 10 km, and we used monthly average temperatures and their standard deviations to correct the bias of the simulated temperatures. We did not use daily averaged temperatures to determine the risk of cool summer damage. Instead, we used the cooling degree calculated from the average daily temperature over a period of time (CDAT). We also used the standardized yield calculated from temperatures during the month preceding heading. An examination of the reproducibility of cooling damage occurring under the current climate was based on bias-corrected data which revealed that although the simulated risk of cool summer damage slightly underestimated both the CDAT and the standardized yield, the areal distributions of risk were similar to those in years of cool summer damage. We assumed that the heading stage occurred 15.6 days earlier than current climate because of the impact of temperature increase under the future climate and therefore calculated the CDAT and standardized yield by advancing the critical period by half a month. During the second- and third-coolest summers under the future climate scenario, the risk of cool summer damage decreased in the southern Tohoku region facing the Pacific Ocean and in Aomori Prefecture on the Japan Sea side, but the risk of cool summer damage was almost the same as during the observed cool summer of 1980. In summary, our results revealed that under a future climate, simulated by the MRI AGCM, the risk of cool summer damage will persist in the Tohoku region; risk management for cool summer damage will therefore be essential, even though global temperatures rise.View full abstractDownload PDF (3996K) -
Taichi MAKI, Osamu MORITA, Yoshinori SUZUKI, Kenji WAKIMIZU, Koji NISH ...2014 Volume 70 Issue 4 Pages 199-211
Published: 2014
Released on J-STAGE: December 10, 2014
JOURNAL FREE ACCESSExperiments of cloud seeding using liquid carbon dioxide (LCD) were carried out on March 14, 2013 near Miyake Island and Mikura Island in the Izu Islands, Tokyo, Japan. Convective clouds near the islands developed 0.5 to 1 h after the seeding. Artificial convective clouds accompanied by rain stream, i.e., virga, were observed, and rain was seen around the islands. Photos from aircraft and satellite images revealed trails and holes of disappeared clouds about 1 h and 2 h later, respectively. Within 1 h, the amount of precipitation was presumed to be about 0.1 million tons, with the precipitation intensity of 1 mm/h, based on a disappeared area 2 km × 50 km, constituting the first direct effect. Within 2 h, the total amount of precipitation from the disappeared cloud was presumed to be 1.8 million tons, based on a disappeared cloud area of diameter 50 km, constituting the secondary indirect effect. The main objective is whether the experiment of artificial rain is a success or not in a meteorological condition. Other objectives were shown successfully by photos taken of virga and the disappeared cloud, and by a satellite image based on the combination of convective cloud and the air temperature inversion layer. We found that LCD seeding at about 5 g/s within convective clouds near their bases is feasible when the air temperature is below 0°C, i.e., suitable around -5°C. The excellence of LCD seeding technique is supported by the results of this study, and we believe this technique will spread worldwide.View full abstractDownload PDF (9174K) -
Prathomrak NA-NGERN, Cattleya CHUTTEANG, Masatoshi AOKI, Fumiaki TAKEM ...2014 Volume 70 Issue 4 Pages 213-222
Published: 2014
Released on J-STAGE: December 10, 2014
JOURNAL FREE ACCESSAir pollutant concentrations such as ozone (O3) and peroxides have been increasing in the world, and may cause many negative impacts on crop production. The objectives of the present study are to investigate the effects of peroxides and O3 on visible foliar injury and physiological responses, and to compare the sensitivities among two Thai rice cultivars, RD 31 and Chainat 1, and two Japanese rice cultivars, Nipponbare and Nourin 52, under exposure to single O3 and combined O3 and peroxides. Four treatment plots were prepared, namely control plot (O3 2-3 ppbv and free peroxides), O3 50 ppbv plot and free peroxides, O3 50 ppbv and peroxides 3 ppbv plot and O3 50 ppbv and peroxides 5 ppbv plot. The results showed that combined O3 and several ppbv peroxides plots caused severe damage on visible leaf injury, increase in Malondialdehyde (MDA) concentration, and decrease in total chlorophyll content and a net photosynthetic rate much higher than single O3 plot. According to the O3 dose response analysis, we found that, in combined O3 (50 ppbv) and peroxides (3 ppbv and 5 ppbv) exposure, in case of visible foliar injury, Chainat 1 was seriously damaged rice cultivar while Nipponbare was a less damaged rice cultivar.View full abstractDownload PDF (2630K) -
Fiolenta MARPAUNG, Takashi HIRANO2014 Volume 70 Issue 4 Pages 223-232
Published: 2014
Released on J-STAGE: December 10, 2014
JOURNAL FREE ACCESSChanges in cloud cover and atmospheric aerosol loading strongly affect the diffuse proportion of solar radiation (Rd/Rg). It has been reported that plant photosynthesis is more efficient under diffuse light conditions, but diffuse radiation (Rd) regimes in tropical peatland frequently subjected to large-scale fires are poorly described, and there are few or no site-based datasets to date. Therefore, we continuously measured Rd for more than three years at a burnt ex-forest on tropical peatland in Central Kalimantan, Indonesia. Daily Rd/Rg was significantly related to the clearness index (Rg/Ro) with a linear threshold model. The model parameters showed that Rd/Rg under a clear sky is larger in tropical peatland with a humid climate than in Australia. Using the model, long-term variation in Rd/Rg for more than 12 years was estimated from Rg measured above a nearby forest. As a result, Rd/Rg showed a seasonal variation with its minimum of 0.51 in June (the transition between the wet and dry seasons) and its maximum of 0.68 in October (the late dry season) on a monthly basis. The decreasing pattern from the late wet season to the early dry season corresponded to decreasing precipitation due to fewer clouds. In contrast, the increasing pattern through the latter half of the dry season was due to shading by smoke emitted through burning biomass and peat fires. In particular, during the El Niño droughts in 2002, 2006 and 2009, the monthly mean Rd/Rg rose above 0.72, because the ground was densely covered with smoke from large-scale fires.View full abstractDownload PDF (2438K)
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