Assessing flood disaster impacts in agriculture under climate change in the river basins of Southeast Asia   总被引：1，自引：0，他引：1  

Shrestha  Badri Bhakta  Perera  Edangodage Duminda Pradeep  Kudo  Shun  Miyamoto  Mamoru  Yamazaki  Yusuke  Kuribayashi  Daisuke  Sawano  Hisaya  Sayama  Takahiro  Magome  Jun  Hasegawa  Akira  Ushiyama  Tomoki  Iwami  Yoichi  Tokunaga  Yoshio 《Natural Hazards》2019,97(1):157-192

Natural Hazards - This study focused on flood damage assessment for future floods under the impact of climate change. Four river basins of Southeast Asia were selected for the study. They included...  相似文献   

Short-term flow fluctuations in Onagawa Bay,Japan, as revealed by long-term mooring observation     

Daisuke Takahashi  Kenji Kaneko  Yasushi Gomi  Yuki Minegishi  Michihiro Shoji  Hikaru Endo  Akihiro Kijima 《Journal of Oceanography》2017,73(1):67-86

Short-term flow fluctuations in the southern central part of Onagawa Bay were examined using long-term mooring and hydrographic data observed during the period from May 2013 to April 2014. The short-term flow fluctuations were dominant in the periodic bands of 15–27 days and shorter than 10 days. The principal and minor components of these flow fluctuations were respectively along and across the local isobaths, which are almost parallel in the north direction. The northward flow fluctuations along the local isobaths were correlated with the northeastward wind fluctuations in both periodic bands, and these correlations were more evident from fall to winter. On the basis of these results, the northward flows are regarded as wind-induced barotropic coastal jets. On other hand, the eastward flow fluctuations across the local isobaths were related to inflow and outflow via the bay mouth or the Izushima Channel. Inflow and outflow with reverse flow at lower depths formed in summer, but those with vertically uniform flow tended to form in winter. The main summertime inflow and outflow were driven by horizontal gradients in density. These permit us to regard the main summertime inflow and outflow as gravitational circulation. Also, the summertime inflow can be intermittently caused by internal waves.  相似文献   

Distribution of boulders at Miyara Bay of Ishigaki Island,Japan: A flow characteristic indicator of tsunami and storm waves     

Kazuhisa Goto  Tetsuya Shinozaki  Koji Minoura  Kiyohiro Okada  Daisuke Sugawara  Fumihiko Imamura 《Island Arc》2010,19(3):412-426

This study investigates the distribution of boulders at Miyara Bay of Ishigaki Island, Japan. These boulders were deposited on a reef flat extending approximately 400–1300 m in width. Most boulders were rectangular to ellipsoidal, without sharp broken edges. They are reef and coral rock fragments estimated as <335 m³ (<633 t). Locally in the bay, the relationship between the boulder weight and position shows that boulders of a given weight have a clear limit on seaward distribution on the reef flat. For example, more than 1, 10, and 100 tons of boulders were deposited, respectively, more than 500, 300, and 100 m from the reef edge. The line is consistent with the possible landward transport limit by maximum storm waves at the Ryukyu Islands, suggesting that the line was formed by the reworking of some boulders by maximally strong storm waves, although we can not exclude the possibility that the line was formed by tsunamis. Furthermore, 68% of boulders at the bay are deposited beyond this line. Therefore, the presence of these boulders at their present positions is difficult to explain solely by storm waves, implying the possible tsunami origin of these boulders. The boulders are characteristically concentrated along the high‐tide line, suggesting the drastic reduction of the tsunami hydraulic force along the line. Previous studies using radiocarbon age dating, as well as our study, imply that at least 69 boulders at Miyara Bay were probably deposited at their present positions by the 1771 Meiwa tsunami, although some of these boulders might have been emplaced and displaced on the reef flat by prior tsunami or storm surges.  相似文献   

Assessing the role of forests in mitigating eutrophication downstream of pasture during spring snowmelt          下载免费PDF全文

Masaaki Chiwa  Sachiko Inoue  Naoaki Tashiro  Daisuke Ohgi  Yoshitoshi Uehara  Hideaki Shibata  Atsushi Kume 《水文研究》2015,29(4):615-623

Little research has examined whether forests reduce stream water eutrophication in agricultural areas during spring snowmelt periods. This study evaluated the role of forests in ameliorating deteriorated stream water quality in agricultural areas, including pasture, during snowmelt periods. Temporal variation in stream water quality at a mixed land‐use basin (565 ha: pasture 13%, forestry 87%), northern Japan, was monitored for 7 years. Synoptic stream water sampling was also conducted at 16 sites across a wide range of forest and agricultural areas in a basin (18.3 km²) in spring, summer and fall. Atmospheric nitrogen (N) and phosphorus (P) deposition were measured for 4 years. The results showed that concentration pulses of nitrate, organic N and total P in stream water were observed when discharge increased during spring snowmelt. Their concentrations were high when silicate concentrations were low, suggesting surface water exported from pasture largely contributed to stream water pollution during snowmelt. Atmospheric N and P deposition (4.1 kg N ha^?1 y^?1; 0.09 kg P ha^?1 y^?1, respectively) was too low to affect the background concentrations of N and P in streams from forested areas. Reduction of eutrophication caused by nutrients from pasture was mainly due to dilution by water containing low concentrations of N and P exported from forested areas, whereas in‐stream reduction was not a dominant process. Results indicate that forests have a limited capacity to reduce the concentration pulses of N and P in stream water during snowmelt in this study basin. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

The behavior and the role of the anti-cyclonic eddy in the Kuroshio large meander development     

Futoki Sakaida  Daisuke Egusa  Hiroshi Kawamura 《Journal of Oceanography》1998,54(1):101-114

The processes underlying the development of the Kuroshio large meanders that occurred in 1986 and 1989 are investigated using a satellite SST data set and hydrographic data. In both processes visible on the satellite SST images, a round-shaped, lower SST region with a diameter of about 200 km is found to the east of the Kuroshio small “trigger” meander (Solomon, 1978) until the region became extinguished near theEnshu Nada. The lower SST region can be interpreted as an anti cyclonic eddy, mainly because of the existence of a warm water mass in the subsurface layer of this region. The warm water mass is characterized by a constant temperature of 18–19°C, the maximum thickness of which is about 400 m. The satellite images show that the eddy is closely related to the Kuroshio path transforming into a shape like the letter “S”. This means that the eddy plays an important role in the development of the Kuroshio large meander since this, too, tends to follow an “S”-shaped path. Added to this, the subsurface layer structure of the eddy is similar to that of the warm water mass offShikoku. This similarity, together with the eddy behavior visible on the satellite SST images, implies that the examined eddy corresponds to the warm water mass offShikoku. In other words, the warm water mass offShikoku can be advected near to theEnshu Nada when the Kuroshio large meander occurs.  相似文献   

Climate projections over different climatic regions of Afghanistan under shared socioeconomic scenarios     

Sediqi  Mohammad Naser  Hendrawan  Vempi Satriya Adi  Komori  Daisuke 《Theoretical and Applied Climatology》2022,149(1-2):511-524

Theoretical and Applied Climatology - The global climate models (GCMs) of Coupled Model Intercomparison Project phase 6 (CMIP6) were used for spatiotemporal projections of precipitation and...  相似文献   

Bunnoite,a new hydrous manganese aluminosilicate from Kamo Mountain,Kochi prefecture,Japan     

Daisuke Nishio-Hamane  Koichi Momma  Ritsuro Miyawaki  Tetsuo Minakawa 《Mineralogy and Petrology》2016,110(6):917-926

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134Cs and 137Cs in the North Pacific Ocean derived from the March 2011 TEPCO Fukushima Dai-ichi Nuclear Power Plant accident,Japan. Part two: estimation of 134Cs and 137Cs inventories in the North Pacific Ocean     

Michio Aoyama  Mizuo Kajino  Taichu Y. Tanaka  Tsuyoshi Thomas Sekiyama  Daisuke Tsumune  Takaki Tsubono  Yasunori Hamajima  Yayoi Inomata  Toshitaka Gamo 《Journal of Oceanography》2016,72(1):67-76

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Petrogenesis and Solidification Depth of the Jurassic Daebo and Cretaceous Bulguksa Granitic Rocks in South Korea     

Etsuo UCHIDA  Seon‐Gyu CHOI  Daisuke BABA  Yusuke WAKISAKA 《Resource Geology》2012,62(3):281-295

We investigated the Jurassic Daebo and Cretaceous Bulguksa granitic rocks in South Korea. The former are distributed mainly in the Gyeonggi and Yeongnam massifs and the latter are present in the Gyeongsan basin and Ogcheon belt. The Daebo granitic rocks generally are of ilmenite series and I to S type. These rocks are associated with Au–Ag hydrothermal deposits, whereas the Bulguksa granitic rocks are of magnetite series and I type, and are associated with Pb–Zn, Cu and Mo–W hydrothermal deposits, as well as Au–Ag hydrothermal deposits. The Daebo granitic rocks show adakitic signatures in their chemical compositions. They are considered to have been derived from partial melting of the thick lower continental crust. Conversely, the Bulguksa granitic rocks in the Gyeongsan basin are non‐adakitic and are considered to have been derived from partial melting of a mantle wedge. Magmas of the Daebo granitic rocks formed at relatively shallow levels, but solidified at deep levels compared with those of the Bulguksa granitic rocks. The Bulguksa granitic rocks in the central to western Ogcheon belt are considered to have been formed by fractionation of magmas derived from partial melting of continental crust. The total Al contents of biotite and hornblende in the granitic rocks increased, with the Bulguksa granitic rocks in the Gyeongsan basin < the Bulguksa granitic rocks in the Ogcheon belt and Gyeonggi and Yeongnam massifs and the Daebo granitic rocks in the Ogcheon belt < the Daebo granitic rocks in the Gyeonggi and Yeongnam massifs. This order corresponds to an increase in solidification depth.  相似文献   

Reaction of forsterite with hydrogen molecules at high pressure and temperature     

Ayako?ShinozakiEmail author  Hisako?Hirai  Hiroyuki?Kagi  Tadashi?Kondo  Taku?Okada  Daisuke?Nishio-Hamane  Shin-ichi?Machida  Tetsuo?Irifune  Takumi?Kikegawa  Takehiko?Yagi 《Physics and Chemistry of Minerals》2012,39(2):123-129

High pressure and temperature reactions of a mixture of forsterite and hydrogen molecules have been carried out using a laser heated diamond anvil cell at 9.8–13.2 GPa and ~1,000 K. In situ X-ray diffraction measurements showed no sign of decomposition or phase transitions of the forsterite under these experimental conditions, indicating that the olivine structure was maintained throughout all runs. However, a substantial expansion of the unit cell volume of the forsterite was observed for samples down to ~3 GPa upon quenching to ambient pressure at room temperature. The Raman spectroscopy measurements under pressure showed significant shifts of the Raman peaks of the Si–O vibration modes for forsterite and of the intramolecular vibration mode for H₂ molecules toward a lower frequency after heating. Additionally, no OH vibration modes were observed by Raman and FT-IR spectroscopic measurements. These lines of evidence show that the observed volume expansion in forsterite is not explained by the incorporation of hydrogen atoms as hydroxyl, but suggest the presence of hydrogen as molecules in the forsterite structure under these high pressure and temperature conditions.  相似文献