A PDF-based hybrid prognostic cloud scheme for general circulation models     

Masahiro Watanabe  S. Emori  M. Satoh  H. Miura 《Climate Dynamics》2009,33(6):795-816

A new cloud parameterization based on prognostic equations for the subgrid-scale fluctuations in temperature and total water content is introduced for global climate models. The proposed scheme, called hybrid prognostic cloud (HPC) parameterization, employs simple probability density functions (PDFs) to the horizontal subgrid-scale inhomogeneity, allowing them to vary in shape in response to small-scale processes such as cumulus detrainment and turbulent mixing. Simple tests indicate that the HPC scheme is highly favorable as compared to a diagnostic scheme in terms of the cloud fraction and cloud water content under either uniform or non-uniform forcing. The relevance of the HPC scheme is investigated by implementing it in an atmospheric component model of the climate model MIROC with a coarse resolution of T42. A comparison of the short-term integrations between the T42 model and a global cloud resolving model (GCRM) reveals that the HPC scheme can reproduce, to a certain degree, the subgrid-scale variance and skewness of temperature and total water content simulated in the GCRM. It is also found that the HPC scheme significantly alters the climatological distributions in cloud cover, precipitation, and moisture, which are all improved from the model using a conventional diagnostic cloud scheme.  相似文献   

Solar Wind Control of Jupiter's H₃Auroras     

R.L. Baron  T. Owen  J.E.P. Connerney  T. Satoh  J. Harrington 《Icarus》1996,120(2):437-442

A program of observations of Jupiter's H⁺₃auroras was conducted during the first 4 months of 1992, a period that spanned the Ulysses encounter. Daily variations of auroral intensity are small in magnitude (∼20%) and well correlated with variations in the solar wind ram pressure arriving at Jupiter. A much larger (factor of 3) time variation is observed to occur on a time scale of approximately 2 months. During the first 2 months of observation, the inferred total intrinsic intensity of the northern aurora exceeded that of the southern aurora by a factor of 2. Throughout the latter 2 months, characterized by less intense auroral activity, the intensity of the northern aurora was comparable to that of the southern aurora.  相似文献   

Petrological characteristics and volatile content of magma from the 2000 eruption of Miyakejima Volcano, Japan     

Genji Saito  Kozo Uto  Kohei Kazahaya  Hiroshi Shinohara  Yoshihisa Kawanabe  Hisao Satoh 《Bulletin of Volcanology》2005,67(7):691-693

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Sulfur stable isotopes indicate the source of sinking materials in a coastal bay: Otsuchi Bay,Sanriku, Japan     

Matheus Carvalho de Carvalho  Ken-ichi Hayashizaki  Hisao Ogawa 《Journal of Oceanography》2008,64(5):705-712

Through 2004 and 2005, δ ³⁴S of sinking material from Otsuchi Bay was measured at the center and rocky shore of the bay. At the center of the bay δ ³⁴S was high (18∼21‰) in the material collected from April to November. However, δ ³⁴S was low (9∼14‰) in the material collected from December to March. The increase in δ ³⁴S in April was attributed to an increase in phytoplankton biomass because marine phytoplanktonic δ ³⁴S is high. When δ ³⁴S of sinking material was low, input of riverine material or bottom sediment resuspension were considered as the probable causes, because their δ ³⁴S is low. Marine sulfur was always high (more than 70%) at both stations. The difference between the δ ³⁴S of sinking material collected from the different sampling stations indicates that marine macroalgae contribute to sinking material near the shore when phytoplankton is scarce. In conclusion, the relative influence of different material sources to sinking materials could be successfully estimated using δ ³⁴S.  相似文献   

Sea level response to wind field fluctuation around the tip of the Izu Peninsula   总被引：1，自引：0，他引：1  

Hirofumi Hinata  Tetsuo Yanagi  Chizuru Satoh 《Journal of Oceanography》2008,64(4):605-620

The mechanism of a characteristic sea level response (barotropic coastal ocean response) to wind field fluctuation around the tip of the Izu Peninsula observed during the middle of December 2000 to the middle of January 2001 was investigated based on three types of numerical experiments using the Princeton Ocean Model with various parameters. The response was characterized by the relaxation of sea level falling (rising) during eastward upwelling (westward downwelling) favorable wind regime. Analyses of quasi-realistic numerical model results in terms of the vertically integrated momentum balances and vorticity balance for the barotropic mode revealed that: 1) development/abatement of two anomalous circulations generated around the tip of the Izu Peninsula controls the sea level response through the acceleration/deceleration of a quasi-geostrophic barotropic coastal current between the circulations; 2) nonlinear vorticity advection by the Kuroshio Current and by the coastal current, coupled with vorticity diffusion, decelerates the quasi-geostrophic coastal current in the latter half of the wind regimes, which induces the relaxation of sea level rise/fall. The results of the quasi-realistic numerical experiment suggest that an analysis of the vorticity balance for the barotropic mode contributes to a better understanding of sea level responses to wind in coastal regions with strong currents and complex topography. In addition, a numerical experiment with idealized spatially uniform density stratification and a quasi-realistic wind field shows that if the Kuroshio Current had been shifted far offshore from the Izu Peninsula during the observation period, westward propagating continental shelf waves would have controlled the coastal sea level response.  相似文献   

Indicators of critical point behavior prior to rock failure inferred from pre-failure damage   总被引：4，自引：0，他引：4  

Xinglin Lei  Takashi Satoh   《Tectonophysics》2007,431(1-4):97

To investigate possible indicators of critical point behavior prior to rock failure, the statistical properties of pre-failure damage were analyzed based on acoustic emission events (AE) recorded during the catastrophic fracture of typical rock samples under differential compression. AEs were monitored using a high-speed 32-channel waveform recording system. Time-dependent statistics, including the energy release rate, b-value of the magnitude–frequency distribution, fractal dimension and spatial correlation length (SCL) of the AE hypocenters were calculated for each data set. Each parameter is a function of the time-to-failure and thus can be treated as an indicator of the critical point. It is clear that the pre-failure damage evolution prior to catastrophic failures in several common rock-types is generally characterized by: 1) accelerated energy release, 2) a decrease in fractal dimension and SCL with a subsequent precursory increase, and 3) a decrease in b-value from  1.5 to  0.5 for hard rocks, and from  1.1 to  0.8 for soft rocks such S–C cataclasite. However, each parameter also reveals more complicated temporal evolution due to either the heterogeneity of the rock mass or the micro-mechanics of shear fracturing. This confirms the potential importance of integrated analysis of two or more parameters for successfully predicting the critical point. The decreasing b-value and increasing energy release may prove meaningful for intermediate-term prediction, while the precursory increase in fractal dimension and SCL may facilitate short-term prediction.  相似文献   

Pliocene and Pleistocene magnetic stratigraphy in Le Castella area,Southern Italy—A preliminary report     

Hisao Nakagawa  Nobuaki Niitsuma  Carlo Elmi 《Quaternary Research》1971

A preliminary study was made of the magnetic stratigraphy of the Pliocene and Lower Pleistocene marine sediments in Le Castella area, Calabria, Southern Italy. Microbiostratigraphic evidence of the measured sediments provides a basis for tentative correlation with the standard magnetic chronology. The Gilsa Event in the Matuyama Reversed Polarity Epoch is estimated to be a little older than the lower limit of the Calabrian in Le Castella area.  相似文献   

Alteration and mass transfer inferred from the Hirabayashi GSJ drill penetrating the Nojima Fault, Japan     

Koichiro Fujimoto  Hidemi Tanaka    Takayuki Higuchi  Naoto Tomida  Tomoyuki Ohtani  Hisao Ito 《Island Arc》2001,10(3-4):401-410

Abstract Mineralogical and geochemical studies on the fault rocks from the Nojima–Hirabayashi borehole, south-west Japan, are performed to clarify the alteration and mass transfer in the Nojima Fault Zone at shallow depths. A complete sequence from the hornblende–biotite granodiorite protolith to the fault core can be observed without serious disorganization by surface weathering. The parts deeper than 426.2 m are in the fault zone where rocks have suffered fault-related deformation and alteration. Characteristic alteration minerals in the fault zone are smectite, zeolites (laumontite, stilbite), and carbonate minerals (calcite and siderite). It is inferred that laumontite veins formed at temperatures higher than approximately 100°C during the fault activity. A reverse component in the movement of the Nojima Fault influences the distribution of zeolites. Zeolite is the main sealing mineral in relatively deep parts, whereas carbonate is the main sealing mineral at shallower depths. Several shear zones are recognized in the fault zone. Intense alteration is localized in the gouge zones. Rock chemistry changes in a different manner between different shear zones in the fault zone. The main shear zone (MSZ), which corresponds to the core of the Nojima Fault, shows increased concentration of most elements except Si, Al, Na, and K. However, a lower shear zone (LSZ-2), which is characterized by intense alteration rather than cataclastic deformation, shows a decreased concentration of most elements including Ti and Zr. A simple volume change analysis based on Ti and Zr immobility, commonly used to examine the changes in fault rock chemistry, cannot account fully for the different behaviors of Ti and Zr among the two gouge zones.  相似文献   

Aerosol properties and air pollutants over an urban area   总被引：2，自引：0，他引：2  

Sonoyo Mukai  Itaru Sano  Mutsumi Satoh  Brent N. Holben 《Atmospheric Research》2006,82(3-4):643

For a better understanding of urban aerosols, sun/sky photometry has been undertaken at the Kinki University campus in Higashi-Osaka as a NASA/AERONET station since 2002. A new instrument, the SPM-613D (Kimoto Electric), has been taking measurements at the same site since March 15, 2004. The relationship between aerosol properties obtained from radiometry with AERONET and the SPM measurements is examined. It is found that there is a linear correlation between SPM concentrations and aerosol properties, which indicates that aerosol characteristics can be estimated from SPM data, and vice versa.It is also shown that the air quality of the Higashi-Osaka site is poor due to not only the anthropogenic particles by local emissions, such as diesel vehicles and chemical industries, but also due to the dust particles coming from continental desert areas by large scale climatic conditions.  相似文献   

Diel tuning of photosynthetic systems in ice algae at Saroma-ko Lagoon, Hokkaido, Japan   总被引：1，自引：0，他引：1  

Shimpei Aikawa  Hiroshi Hattori  Yasushi Gomi  Kentaro Watanabe  Sakae Kudoh  Yasuhiro Kashino  Kazuhiko Satoh 《Polar Science》2009,3(1):57-72

Ice algae are the major primary producers in seasonally ice-covered oceans during the cold season. Diurnal change in solar radiation is inevitable for ice algae, even beneath seasonal sea ice in lower-latitude regions. In this work, we focused on the photosynthetic response of ice algae under diurnally changing irradiance in Saroma-ko Lagoon, Japan. Photosynthetic properties were assessed by pulse-amplitude modulation (PAM) fluorometry. The species composition remained almost the same throughout the investigation. The maximum electron transport rate (rETR_max), which indicates the capacity of photosynthetic electron transport, increased from sunrise until around noon and decreased toward sunset, with no sign of the afternoon depression commonly observed in other photosynthetic organisms. The level of non-photochemical quenching, which indicates photoprotection activity by dissipating excess light energy via thermal processes, changed with diurnal variations in irradiance. The pigment composition appeared constant, except for xanthophyll cycle pigments, which changed irrespective of irradiance. These results indicate that ice algae tune their photosynthetic system harmonically to achieve efficient photosynthesis under diurnally changing irradiance, while avoiding damage to photosystems. This regulation system may be essential for productive photosynthesis in ice algae.  相似文献