Rainfall on the Meghalaya plateau in northeastern India—one of the rainiest places in the world     

Fumie Murata  Taiichi Hayashi  Jun Matsumoto  Haruhisa Asada 《Natural Hazards》2007,42(2):391-399

Monthly and daily variations in rainfall over Cherapunjee and Mawsynram on the Meghalaya plateau of northeastern India are analysed. Cherapunjee and Mawsynram are well known as two of the places with the heaviest rainfall in the world. The daily rainfall variation is attributed to the influence of synoptic scale disturbances, with a periodicity of 10–20 days, and the orographic interaction. The annual and monthly highest rainfalls over Cherapunjee during the 31 years from 1973 to 2003 were much larger than mean values.  相似文献   

Divergence of high-degree harmonic solutions of a rotating elliptical earth     

Wenke Sun  Ichiro Murata 《Geophysical Journal International》1994,118(1):269-271

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Halogen acids in fumarolic gases of Kilauea volcano     

K. J. Murata  W. U. Ault  D. E. White 《Bulletin of Volcanology》1964,27(1):365-368

The water-rich condensates of fumarolic gases, obtained from degassing lavas of the 1959–60 eruption of Kilauea volcano, contain unexpectedly high concentrations of hydrofluoric and hydrochloric acids, and thereby suggest that halogens are significant constituents of basaltic magmas. Vents on the pumice hill of Kilauea Iki yielded one sample that contained, in parts per million, 21,000 HF (1.1 N) with 2,920 HCl, and another sample, 20 HF with 70,500 HCl (2.0 N). Samples from vents elsewhere on the volcano had from one-fortieth to one-thousandth as much of the two acids. A rough correlation exists between the temperature of the fumaroles (range 110 to 820°C) and the total concentration of the halogen acids. This correlation is mainly due to progressive dilution of the magmatic halogen acids by water of probable meteoric origin in fumaroles of lower temperatures. Variations in the HF/HCl ratio (range 0.0003 to 7.2) may be explained by means of two different processes whose relative importance cannot be assessed with the data at hand (1). In their migration to the surface, the acid gases may have reacted with the lava to a variable extent owing to the widely different configurations of the several vents (steaming areas in glassy pumice, glowing cracks, and drillhole in lava lake). In the reaction, relatively more HF could have reacted at temperatures around 300°C with the glassy pumice (2). There is some indication that the HF/HCl ratio increases with time,suggesting that the crystallizing lava may have released HCl early, with HF concentrated in the later exhalations. The Br/Cl ratio ranges from 0.0036 down to 0.0014, as compared to 0.0034 of seawater.  相似文献   

Estimation of urban heat island intensity using biases in surface air temperature simulated by a nonhydrostatic regional climate model     

Akihiko Murata  Hidetaka Sasaki  Mizuki Hanafusa  Kazuo Kurihara 《Theoretical and Applied Climatology》2013,112(1-2):351-361

This study demonstrates that urban heat island (UHI) intensity can be estimated by comparing observational data and the outputs of a well-developed high-resolution regional climate model. Such an estimate is possible because the observations include the effects of UHI, whereas the model used does not include urban effects. Therefore, the errors in the simulated surface air temperature, defined as the difference between simulated and observed temperatures (simulated minus observed), are negative in urban areas but 0 in rural areas. UHI intensity is estimated by calculating the difference in temperature error between urban and rural areas. Our results indicate that overall UHI intensity in Japan is 1.5 K and that the intensity is greater in nighttime than in daytime, consistent with the previous studies. This study also shows that root mean square error and the magnitude of systematic error for the annual mean temperature are small (within 1.0 K).  相似文献   

Late Ediacaran crustal thickening in Iran: Geochemical and isotopic constraints from the ~550 Ma Mishu granitoids (northwest Iran)     

Malihe Shahzeidi  Mohsen Moayyed  Mamoru Murata  Tzen-Fu Yui  Shoji Arai  Fukun Chen 《International Geology Review》2017,59(7):793-811

The aim of this article is to examine the geochemistry and geochronology of the Cadomian Mishu granites from northwest Iran, in order to elucidate petrogenesis and their role in the evolution of the Cadomian crust of Iran. The Mishu granites mainly consist of two-mica granites associated with scarce outcrops of tonalite, amphibole granodiorite, and diorite. Leucogranitic dikes locally crosscut the Mishu granites. Two-mica granites show S-type characteristics whereas amphibole granodiorite, tonalities, and diorites have I-type signatures. The I-type granites show enrichment in large-ion lithophile elements (e.g. Rb, Ba and K) and depletion in high field strength elements (e.g. Nb, Ti and Ta). These characteristics show that these granites have been formed along an ancient, fossilized subduction zone. The S-type granites have high K, Rb, Cs (and other large ion lithophile elements) contents, resembling collision-related granites. U–Pb zircon dating of the Mishu rocks yielded ²³⁸U/²⁰⁶Pb crystallization ages of ca. 550 Ma. Moreover, Rb–Sr errorchron shows an early Ediacaran age (547 ± 84 Ma) for the Mishu igneous rocks. The two-mica granites (S-type granites) show high ⁸⁷Sr/⁸⁶Sr_(i) ratios, ranging from 0.7068 to 0.7095. Their ?Nd values change between ?4.2 and ?4.6. Amphibole granitoids and diorites (I-type granites) are characterized by relatively low ⁸⁷Sr/⁸⁶Sr_(i) ratios (0.7048–0.7079) and higher values of ?Nd (?0.8 to ?4.2). Leucogranitic dikes have quite juvenile signature, with ?Nd values ranging from +1.1 to +1.4 and Nd model ages (T_DM) from 1.1 to 1.2 Ga. The isotopic data suggests interaction of juvenile, mantle-derived melts with old continental crust to be the main factor for the generation of the Mishu granites. Interaction with older continental crust is also confirmed by the presence of abundant inherited zircon cores. The liquid-line of descend in the Harker diagrams suggests fractional crystallization was also a predominant mechanism during evolution of the Mishu I-type granites. The zircon U–Pb ages, whole rock trace elements, and Sr–Nd isotope data strongly indicate the similarities between the Mishu Cadomian granites with other late Neoproterozoic–early Cambrian (600–520 Ma) granites across Iran and the surrounding areas such as Turkey and Iberia. The generation of the Mishu I-type granites could be related to the subduction of the Proto-Tethyan Ocean during Cadomian orogeny, through interaction between juvenile melts and old (Mesoproterozoic or Archaean) continental crust. The S-type granites are related to the pooling of the basaltic melts within the middle–upper parts of the thick continental crust and then partial melting of that crust.  相似文献   

Paleomagnetism of Cretaceous Red beds from Eastern Part of South China Block     

Hayao Morinaga  Hiroyuki Kashimura 《中国地质大学学报(英文版)》1999,10(3)

INTRODUCTIONCollisionofIndiawithAsiaappearstohavebroughtaboutlargetectonicdeformationofAsia,especiallyEastAsia(Tapponnieretal.,1986).Post-Cretaceousdeformation(translationand/orrotation)ofSimaoandIndochinablocks,whicharelocatedatthesouthernsideofRedRiverfault(RRF),hasbeenreportedfromCretaceouspaleomagneticin-vestigations(Yangetal.,l995;HuangandOpdyke,l993IYangandBesse,1993).AlsoinSouthChinablock(SCB)locatedatnorthsideoftheRRF,localdeformationofsomeregionsneartheRRFhasbeendocum…  相似文献   

VSOP monitoring of the Quasar 1928+738     

D. W. Murphy  S. J. Tingay  R. A. Preston  D. L. Meier  D. L. Jones  J. C. Guirado  A. Polatidis  J. E. Conway  H. Hirabayashi  H. Kobayashi  Y. Murata 《New Astronomy Reviews》1999,43(8-10)

We present the results from a campaign to monitor the relatively low redshift (z=0.3) circumpolar superluminal quasar 1928+738 with VSOP during the first Announcement of Opportunity period. The four epochs of data show that there have been substantial structural changes in this source near the core on the time-scale of a few months.  相似文献