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91.
The possible change in the characteristics of weather in the future should be considered as important as the mean climate change because the increasing risk of extremes is related to the variability on daily time scales. The weather characteristics can be represented by the climatological mean interdiurnal (day-to-day) variability (MIDV). This paper first assessed the phase five of the Coupled Model Intercomparison Project coupled climate models’ capability to represent MIDV for the surface maximum and minimum temperature, surface wind speed and precipitation under the present climate condition. Based on the assessment, we selected three best models for projecting future change. We found that the future changes in MIDV are characterized by: (a) a marked reduction in surface maximum and minimum temperature over high latitudes during the cold season; (b) a stronger reduction in the surface minimum temperature than in the maximum temperature; (c) a reduction in surface wind speed over large parts of lands in Northern Hemisphere (NH) during NH spring; (d) a noticeable increase in precipitation in NH mid-high latitudes in NH spring and winter, and in particular over East Asia throughout most of the year. 相似文献
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93.
Takehiko Mori Yasuaki Sudo Tomoki Tsutsui Shin Yoshikawa 《Bulletin of Volcanology》2008,70(9):1031-1042
Isolated-type tremors having two events with different dominant frequencies are characteristic seismological phenomena observed
during the fumarolic activity stage at Aso Volcano. These isolated tremors are called hybrid tremors (HBT) and comprise two
parts: an initial part named the “HF-part” with a dominant frequency in the high-frequency region (approximately 10 Hz) and
the following part named the “LF-part” with a dominant frequency in the low-frequency region (approximately 2 Hz). The LF-part
is observed after the HF-part, and the HBT is accompanied by a long-period tremor (LPT). Hypocenters and source parameters
are estimated using seismograms recorded at 64 stations around Nakadake crater. The amplitude distributions of all HF-parts
have almost similar trends. Similarly, the amplitude distributions of all LF-parts have almost similar trends. However, the
amplitude distributions of HF- and LF-parts are not similar. From these results, we proposed that the hypocenters and source
parameters of HF- and LF-parts are not common, but each of them have common hypocenters and source parameters. The hypocenter
region of HF-parts was estimated to be just beneath the fumarole region south of the 1st crater: the volume fluctuation is
the major source factor. The hypocenter region of LF-parts is estimated to be at a depth of approximately 300 m beneath the
first crater: the strike–slip component is the major source parameter. The hypocentral depth of LF-parts is located at the
upper end of the crack estimated to be the source of the LPTs. The LPTs and HBTs are observed almost simultaneously. We consider
that volcanic fluid is involved in the source mechanisms of both HBT and LPT. 相似文献
94.
Polychaetes are suitable organisms for evaluation of impact of sediment pollution. We evaluated toxicity of cadmium and copper and measured metallothionein-like proteins (MTLPs) in the polychaete Perinereis nuntia. At the same concentration ranges copper was unexpectedly more toxic than cadmium. Copper also caused no significant increase in MTLPs in the polychaetes. When P. nuntia and another polychaete species, Cirratulus cirratus were cultured in the contaminated sediments collected from Lake Sihwa (Korea), a high mortality of 80% was observed on day 6 in P. nuntia in the sediment with the highest metal concentration. However, no mortality was observed up to 35 days in C. cirratus in any sediment. MTLP contents between two species also varied. These findings suggest that MTLP induction response in the polychaetes varies with the metal type and species and it may be used as a biomarker of sediment pollution in the polychaetes after further validation and field trials. 相似文献
95.
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97.
Muhammad Ilyas Agus Sudaryanto Iwan Eka Setiawan Tomohiko Isobe Shin Takahashi 《Marine pollution bulletin》2011,62(1):89-98
A total of 33 surficial sediments from riverine and coastal waters from Surabaya, Indonesia were analyzed for PCBs and BFRs. Concentrations of PCBs (62 congeners), PBDEs (14 congeners) and HBCDs (3 isomers) varied from <DL-420, <DL-35 and <DL-5.4 ng g−1 dw, respectively. Higher concentrations of these compounds were found in riverine than coastal sediments. Their levels and distribution were influenced by proximity to the point sources and TOC. The predominant congeners were CB-153, -28, -138, -149, -180, -33 and BDE-209, -207, -206, -197, -196, -183, -99, -47 for PCBs and PBDEs, respectively, and γ-isomer for HBCDs. Debromination of BDE-209 might be taking place producing lower toxic congeners in sediment. Levels of PCBs in riverine sediments were comparable with some polluted areas worldwide, but PBDEs and HBCDs were lower. Hazard assessment of PCBs indicated possible toxic potential, particularly in areas close to point sources. 相似文献
98.
99.
Application of the ALE technique for underwater explosion analysis of a submarine liquefied oxygen tank 总被引:1,自引:0,他引:1
The design of submarines has continually evolved to improve survivability. Explosions may induce local damage as well as global collapse to a submarine. Therefore, it is important to realistically estimate the possible damage conditions due to underwater explosions in the design stage. The present study applied the Arbitrary Lagrangian–Eulerian (ALE) technique, a fluid–structure interaction approach, to simulate an underwater explosion and investigate the survival capability of a damaged submarine liquefied oxygen tank. The Lagrangian–Eulerian coupling algorithm, the equations of state for explosives and seawater, and the simple calculation method for explosive loading were also reviewed. It is shown that underwater explosion analysis using the ALE technique can accurately evaluate structural damage after attack. This procedure could be applied quantitatively to real structural design. 相似文献
100.
A time-series sediment trap was deployed at 1,034 m water depth in the eastern Bransfield Strait for a complete year from
December 25, 1998 to December 24, 1999. About 99% of total mass flux was trapped during an austral summer, showing distinct
seasonal variation. Biogenic particles (biogenic opal, particulate organic carbon, and calcium carbonate) account for about
two thirds of annual total mass flux (49.2 g m-2), among which biogenic opal flux is the most dominant (42% of the total flux). A positive relationship (except January) between
biogenic opal and total organic carbon fluxes suggests that these two variables were coupled, due to the surface-water production
(mainly diatoms). The relatively low δ13C values of settling particles result from effects on C-fixation processes at low temperature and the high CO2 availability to phytoplankton. The correspondingly low δ15N values are due to intense and steady input of nitrates into surface waters, reflecting an unlikely nitrate isotope fractionation
by degree of surface-water production. The δ15N and δ13C values of sinking particles increased from the beginning to the end of a presumed phytoplankton bloom, except for anomalous
δ15N values. Krill and the zooplankton fecal pellets, the most important carriers of sinking particles, may have contributed
gradually to the increasing δ13C values towards the unproductive period through the biomodification of the δ13C values in the food web, respiring preferentially and selectively12C atoms. Correspondingly, the increasing δ15N values in the intermediate-water trap are likely associated with a switch in source from diatom aggregates to some remains
of zooplankton, because organic matter dominated by diatom may be more liable and prone to remineralization, leading to greater
isotopic alteration. In particular, the tendency for abnormally high δ15N values in February seems to be enigmatic. A specific species dominancy during the production may be suggested as a possible
and speculative reason. 相似文献