排序方式： 共有27条查询结果，搜索用时 31 毫秒
1.
Climatic Change - The objective of this study is to assess the global impact of sea level rise and to evaluate the effectiveness of adaptation. Global areas of inundation due to sea level rise are... 相似文献
2.
Duong Du Bui Akira Kawamura Thanh Ngoc Tong Hideo Amaguchi Naoko Nakagawa 《Hydrogeology Journal》2012,20(8):1635-1650
A groundwater-monitoring network has been in operation in the Red River Delta, Vietnam, since 1995. Trends in groundwater level (1995?C2009) in 57 wells in the Holocene unconfined aquifer and 63 wells in the Pleistocene confined aquifer were determined by applying the non-parametric Mann-Kendall trend test and Sen??s slope estimator. At each well, 17 time series (e.g. annual, seasonal, monthly), computed from the original data, were analyzed. Analysis of the annual groundwater-level means revealed that 35?% of the wells in the unconfined aquifer showed downward trends, while about 21?% showed upward trends. On the other hand, confined-aquifer groundwater levels experienced downward trends in almost all locations. Spatial distributions of trends indicated that the strongly declining trends (>0.3?m/year) were mainly found in urban areas around Hanoi where there is intensive abstraction of groundwater. Although the trend results for most of the 17 time series at a given well were quite similar, different trend patterns were detected in several. The findings reflect unsustainable groundwater development and the importance of maintaining groundwater monitoring and a database in the Delta, particularly in urban areas. 相似文献
3.
4.
Naoto Inoue Naoko Kitada Keiji Takemura Koji Fukuda Tsuyoshi Emura 《Geotechnical and Geological Engineering》2013,31(3):881-890
The three-dimensional subsurface structure model around Kansai International Airport (KIX) has been developed based on the geologically and geotechnically investigated results of a large amount of borehole data for estimation of subsidence. The model consists of the alternation of marine clay and coarse deposits. The many seismic surveys and borehole drillings were carried out around the KIX before the constructing the airport. The stratigraphy of the model was renewed by the KIX18-1, which was about 1,300 m long drilling core and was drilled near the 2nd runway of the KIX from 2006 to 2007. In this study, the subsurface geological model was revised by integration of renewed borehole data and seismic profiles to incorporate complex warping structure and heterogenic lateral variation. 相似文献
5.
In order to understand the metal concentrations in Japanese eel Anguilla japonica, nine elements were analyzed in the livers of different migratory types of eels collected from Tokushima region (south Japan). Migratory types were defined by examining the Sr:Ca ratio in otoliths. The results showed that there were significant differences in V, Cr, Cd, and Pb concentrations among the migratory types. Mature-sea-eels show a higher risk of metal accumulation than other migratory types of eels, and the concentrations of Mn, Cu, and Zn in mature eels were significantly higher than those in immature eels. The study suggests that the eel liver is a valuable bioindicator for trace metals; however, when using the eel as a bioindicator to reveal the pollutants in aquatic systems, life history analysis should be carried out for accurate interpretation of the results. 相似文献
6.
The pattern of the ionospheric electric field around the westward travelling surge (WTS) is theoretically studied. This is obtained by solving the current continuity equation at the ionospheric altitude for temporal and spatial development of the field-aligned current density modelled as the WTS phenomenon. The results show that the divergence of the ionospheric electric field is significantly changed depending on the dawn-to-dusk convection electric field E0 because of non-uniformity in the ionospheric conductivity: the ionospheric electric field diverges in the upward current region (around the head of the WTS) when a westward electric field E0 of 10 mV m−1 is uniformly applied. On the other hand, the ionospheric electric field converges without E0. From the observational inference that the ionospheric electric field converges around the head of the WTS, it is suggested that the WTS phenomenon may not be accounted for by the discharging process in the presence of the enhanced dawn-to-dusk convection electric field and non-uniform conductivity as was studied by previous authors. 相似文献
7.
峨眉山地区大气漂尘化学组成研究 总被引：2，自引：0，他引：2
为了揭示峨眉山大气漂尘的化学特征，研究小组分别在1998，1999，2000年使用小型大气采样器进行采样，并测得样品中含有水溶性化学成分（Na^ ,K^ ,Mg^2 ,Ca^2 ,SO4^2-,NO3^-,NH4^ 和Cl^-)和酸溶性化学成分（Pb和Zn)。这一地区三年的大气成分与1990年的相似，而且峨眉山的Na^ ,Cl^-,SO4^2-,NO3^-,Ca^2 ,NH4^ ，Pb和Zn浓度分别比日本山形县鹤岗的要高出4－15，3－19，3－5，3－6，13－23，4－7，11－28和10－23倍之多。 相似文献
8.
Though high rates of nitrate (NO3−) leaching from forests are undesirable, the factors significantly regulating stream NO3− concentration is not clarified yet. In Japan, not only near metropolitan areas but also the Japan Sea-side area with heavy snowfall is well known for receiving more than 10 kg-N ha−1 year−1 of nitrogen (N) deposition. However, NO3− concentration in stream water is relatively low in the Japan Sea-side area compared with its concentration in other areas. We examined important environmental factors regulating stream NO3− concentrations at baseflow condition in a large region of Japan, the Kinki region (KIN) including a part of Japan Sea-side (JSK) using Random Forest regression. The amounts of N deposition and precipitation were common regulating factors for stream NO3− concentration at baseflow condition. Random forest showed the significant correlation between the factors related to ecosystem N retention and stream NO3− concentration at baseflow condition, and it suggests that large N deposited during the growing season was incorporated into the ecosystem in the entire KIN. Heavy rain and snow flush N and wash out N accumulated in the surface soil, causing small N accumulation in forests. Also, large precipitation dilute NO3− concentration in baseflows. These things lowered stream NO3− concentration at baseflow condition. Especially in JSK, most of N deposed with the heavy snow flushed out during the snowmelt period. We provided the first statistical confirmation using Random Forest regression that N accumulation and cycling in forest ecosystems were related to NO3− leaching from forests into streams. 相似文献
9.
10.
Satoru Takanashi Yoshiko Kosugi Shinjiro Ohkubo Naoko Matsuo Makoto Tani Abdul Rahim Nik 《水文研究》2010,24(4):472-480
We measured the fluxes of sensible and latent heat between a low‐land dipterocarp forest in Peninsular Malaysia and the atmosphere. No clear seasonal or interannual changes in latent heat flux were found from 2003 to 2005, while sensible heat flux sometimes fluctuated depending on the fluctuation of incoming radiation between wet and dry seasons. The evapotranspiration rates averaged for the period between 2003 and 2005 were 2·77 and 3·61 mm day?1 using eddy covariance data without and with an energy balance correction, respectively. Average precipitation was 4·74 mm day?1. Midday surface conductance decreased with an increasing atmospheric water vapour pressure deficit and thus restricted the excess water loss on sunny days in the dry season. However, the relationship between the surface conductance and vapour pressure deficit did not significantly decline with an increase in volumetric soil water content even during a period of extremely low rainfall. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献