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Factors controlling typhoons and storm rain on the Korean Peninsula during the Little Ice Age 总被引：1，自引：0，他引：1
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A new method was developed to compare the classifications of different kind of data maps based on the self-organizing map (SOM) analysis. The surface current maps of the northern coast of Ishigaki and Iriomote Islands, East China Sea, observed by high-frequency (HF) radar were classified by SOM. Winds, sea surface temperatures (SST), and reanalysis data were also classified by SOM. The optimum area for classification was determined objectively by the new method, which relates these patterns to HF radar current patterns. We found two typical surface patterns: the first was that northeastward flows are dominant in the observation area and the second was that a clockwise eddy was also dominant in this area. The southwestward wind pattern was strongly related to the dominant clockwise eddy pattern of the HF radar current field. 相似文献
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Abstract: Advanced techniques are examined to observe microstructure of rocks using image analysis combined with methods such as the fluorescent approach and the application of optical characteristics of minerals. Analyzed are discrimination of grains in rocks, distribution patterns of grain orientation in sandstone, changes of grain shape as weathering advances and distribution patterns of microcracks in granite. In Shirahama sandstone, relatively large and flat grains are orientated parallel to the bedding on the plane perpendicular to the bedding, while grains on the plane parallel to the bedding show random patterns. In weathered granite, it is clarified that the grain surface becomes complex as weathering advances and differences among three major mineral species are identified. In Inada granite, intracrystalline cracks predominate over intercrystalline cracks and grain boundary cracks both in total length and number. Furthermore, three types of microcracks show different orientations; the intercrystalline cracks show a dominant orientation which coincides with the orientation of the rift plane, the easiest plane to split, while the intracrystalline cracks and grain boundary cracks show no preferred orientation. 相似文献
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A. Kouchi Y. Sugawara K. Kashima I. Sunagawa 《Contributions to Mineralogy and Petrology》1983,83(1-2):177-184
Sector zoning has been experimentally reproduced in CaMgSi2O6-CaTiAl2O6 clinopyroxene crystals by isothermal crystallization using seed crystals. Element partitioning in different growth sectors and between the core and rim portions in single crystals was analysed in relation to growth rate R and degree of supercooling T. The TiO2 and Al2O3 contents increase with increase in R and T, but when they are compared between different sectors in a single crystal grown at the same T, they correlate negatively with R. The order of faces in respect of contents of TiO2 and Al2O3 is (100)>(110)(010)(111) at T= 13° C and 18° C but changes to (110)>(100)>(010)>(111) at T= 25° C. The growth mechanism is concluded to be controlled by interface kinetics at T= 13–25° C for all these faces, while at T=45° C this relation holds for (100) and (010) faces, but not for (110) and (111), based on the growth rate versus supercooling relation and surface microtopographic observations. The interface kinetics play the essential role in the formation of sector zoning, when the layer growth mechanism takes place. 相似文献
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Minoru Ando Tetsuya Nagata Shuji Sato Makoto Watanabe Kunio Itoh Toshihide Kawai Hidehiko Nakaya Yoshiharu Namba Takeshi Takezawa 《Experimental Astronomy》2002,13(3):119-134
We constructed a wide field cryogenic telescope (WFCT) containing a whole Ritchey-Chrétien system and a focal plane array
in a cryostat for near infrared observations to cover the field of view of 0.4°. The telescope has a primary mirror of 220
mm and an engineering grade 256 × 256 InSb array. The optical components such as two mirrors, filters, spiders, and radiation
shield tube are cooled down to 180 K as well as the InSb array to 35 K by a mechanical refrigerator. We show the results of
the background surface brightnesses and the limiting magnitudes at 3.3 and 3.67 μm measured at Sutherland, South Africa. We
describe the on-going upgrade of this instrument, equipped with a 1024 × 1024 ALADDIN InSb science grade array.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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Site effects by generalized inversion technique using strong motion recordings of the 2008 Wenchuan earthquake 总被引：3，自引：1，他引：2
The generalized inversion of S-wave amplitude spectra from the free-field strong motion recordings of the China National Strong Motion Observation Network System (NSMONS) are used to evaluate the site effects in the Wenchuan area. In this regard, a total of 602 recordings from 96 aftershocks of the Wenchuan earthquake with magnitudes of M3.7-M6.5 were selected as a dataset. These recordings were obtained from 28 stations at a hypocenter distance ranging from 30 km to 150 km. The inversion results have been verified as reliable by comparing the site response at station 62WUD using the Generalized Inversion Technique (GIT) and the Standard Spectral Ratio method (SSR). For all 28 stations, the site predominant frequency F p and the average site amplification in different frequency bands of 1.0–5.0 Hz, 5.0–10.0 Hz and 1.0–10.0 Hz have been calculated based on the inversion results. Compared with the results from the horizontal-to-vertical spectral ratio (HVSR) method, it shows that the HVSR method can reasonably estimate the site predominant frequency but underestimates the site amplification. The linear fitting between the average site amplification for each frequency band and the V s20 (the average uppermost-20 m shear wave velocity) shows good correlation. A distance measurement called the asperity distance D Aspt is proposed to reasonably characterize the source-to-site distance for large earthquakes. Finally, the inversed site response is used to identify the soil nonlinearity in the main shock and aftershocks of Wenchuan earthquake. In ten of the 28 stations analyzed in the main shock, the soil behaved nonlinearly, where the ground motion level is apparently beyond a threshold of PGA > 300 cm/s2 or PGV > 20 cm/s, and only one station coded 51SFB has evidence of soil nonlinear behavior in the aftershocks. 相似文献
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Motohiko Kashima Shin-Ichi Ito Kaoru Ichikawa Shiro Imawaki Shin-Ichiro Umatani Hiroshi Uchida Takashi Setou 《Journal of Oceanography》2009,65(1):73-80
A quasiperiodic variation of 100–110 days in the Kuroshio path off Cape Ashizuri, resulting from the passage of small meanders,
was detected by observation with moored current meters during 1993–1995. TOPEX/POSEIDON altimeter data covering 9 years showed
that the quasiperiodic variation period was not persistent and modulated twice, with a ∼110-day period from mid-1993 to late
1996, a ∼150-day period from late 1996 to mid-1999, and a ∼110-day period from mid-1999 to late 2001. The quasiperiodic variations
of the Kuroshio path migration were contemporaneous with the quasiperiodic arrivals of mesoscale eddies from the east along
27–32°N over the same ∼110- and ∼150-day period quasiperiodic variations. The periodic arrivals of the eddies configure the
periodic variations of the Kuroshio path and its inter-annual modulation. 相似文献
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Etsuo Uchida Takuro Haitani Takayuki Suetsugu Takahiro Kashima Ken Tsutsui 《Resource Geology》2003,53(2):155-161
Abstract. The distribution of Na, K, Ca, Mg, Mn and Fe between the granodiorite JG-la, one of the geochemical standard rocks, and 2M NaCl aqueous solution was experimentally determined at temperatures of 300 to 800C and a pressure of 1 kb using standard cold seal-type pressure vessels. The solid run products melted partially at 800C. Only K shows a significantly different behavior from the experiments using the basalt JB-la (Uchida and Tsutsui, 2000) due to the presence of ortho-clase in the JG-la. The transition elements tend to be preferably partitioned into the aqueous chloride solutions with increasing temperature. At 800C and 1 kb, the Fe concentration of the aqueous chloride solutions reached up to 5,000 ppm, and the Mn concentration up to 350 ppm. The distribution coefficient, KD, i = Ci, sol /Ci , rock, is in the order of Na>K>Mn>Ca> Fe>Mg at 300C, but changed in the order of Mn>N>K>Fe>Ca>Mg at 800C. The distribution coefficients of the divalent cations for the JG-la are higher than those for the JB-1a. The distribution coefficient of the transition elements, Fe and Mn, increases significantly with increasing temperature. The thermodynamic analysis for aqueous speciation revealed that this is attributable to the formation of the tri-chloro complexes of the transition elements at higher temperatures. 相似文献
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