Influence of a rock glacier spring on the stream energy budget and cold‐water refuge in an alpine stream          下载免费PDF全文

Jordan S. Harrington  Masaki Hayashi  Barret L. Kurylyk 《水文研究》2017,31(26):4719-4733

The thermal regimes of alpine streams remain understudied and have important implications for cold‐water fish habitat, which is expected to decline due to climatic warming. Previous research has focused on the effects of distributed energy fluxes and meltwater from snowpacks and glaciers on the temperature of mountain streams. This study presents the effects of the groundwater spring discharge from an inactive rock glacier containing little ground ice on the temperature of an alpine stream. Rock glaciers are coarse blocky landforms that are ubiquitous in alpine environments and typically exhibit low groundwater discharge temperatures and resilience to climatic warming. Water temperature data indicate that the rock glacier spring cools the stream by an average of 3 °C during July and August and reduces maximum daily temperatures by an average of 5 °C during the peak temperature period of the first two weeks in August, producing a cold‐water refuge downstream of the spring. The distributed stream surface and streambed energy fluxes are calculated for the reach along the toe of the rock glacier, and solar radiation dominates the distributed stream energy budget. The lateral advective heat flux generated by the rock glacier spring is compared to the distributed energy fluxes over the study reach, and the spring advective heat flux is the dominant control on stream temperature at the reach scale. This study highlights the potential for coarse blocky landforms to generate climatically resilient cold‐water refuges in alpine streams.  相似文献   

Alkalinization and acidification of stream water with changes in atmospheric deposition in a tropical dry evergreen forest of northeastern Thailand          下载免费PDF全文

Hiroyuki Sase  Jesada Luangjame  Hathairatana Garivait  Bopit Kietvuttinon  Thiti Visaratana  Masato Kamisako  Ryo Kobayashi  Seiichi Ohta  Junko Shindo  Kentaro Hayashi  Hideshige Toda  Kazuhide Matsuda 《水文研究》2017,31(4):836-846

Field surveys on atmospheric deposition and stream water chemistry were conducted in an evergreen forest in northeastern Thailand characterized by a tropical savanna climate with distinct dry and wet seasons. Atmospheric deposition of ion constituents by throughfall and stemflow was shown to increase in the beginning and end of the wet season, reflecting the precipitation pattern. The pH and electrical conductivity of stream water increased with alkalinity and base cation concentrations due to mineralization of organic matter by the first rain and retention of anions in soil during the start of the wet season. After initial alkalinization, the pH and alkalinity declined rapidly with the highest SO₄^2? concentration displayed in the middle towards the end of the wet season. The magnitude of peaks in SO₄^2? concentration (13.5–60.6 μmol_c/L) reflects deposition during the first 2 months of the wet season (March and April) in respective years (60.8–170 mol_c/ha). Release of SO₄^2? with H⁺, which is retained in soil during the early wet season, may cause acidification later in the season. The deposition and concentration of SO₄^2? declined over 6 years. However, the pH of stream water declined with increasing concentrations of SO₄^2? and other major ions. The release of materials accumulated in the ecosystem was facilitated by the decrease in SO₄^2? concentration/deposition and increased precipitation in the middle–late wet season. The retention‐release cycle of SO₄^2? largely contributed to both seasonal and interannual variations in stream water chemistry in the tropical savanna climate studied.  相似文献   

Comparative analysis of measurements of stratospheric aerosol by lidar and aerosol sonde above Ny-Ålesund in the winter of 1995 [Comparative analysis of lidar and OPC observations]     

Koichi Shiraishi  Masahiko Hayashi  Motowo Fujiwara  Takashi Shibata  Masaharu Watanabe  Yasunobu Iwasaka  Roland Neuber  Takashi Yamanouchi 《Polar Science》2011,5(4):399-410

Solid polar stratospheric cloud (PSC) layers observed by lidar and a balloon-borne optical particle counter (OPC) on 17 December 1995 are reexamined in a comparative analysis framework. The typical radius of solid particles in the observed PSC is determined through the comparative analysis to have been approximately 2.3 μm. A backward trajectory analysis for the air mass in which the solid particles were observed shows that the air mass had experienced temperatures 2–3 K below the frost point of nitric acid tri-hydrate (NAT) during the 4 days preceding the observations. The back-trajectory analysis traces the air mass back to northern Greenland and Ellesmere Island on 16 December, one day before the observations. A microphysical box model is used to investigate possible mechanisms of formation for the observed solid particles. The results of this model suggest that the solid particles formed under mesoscale temperature fluctuations associated with mountain lee wave activity induced by the relatively high terrestrial elevations of northern Greenland and Ellesmere Island.  相似文献   

Mineralogy,Sulfur Isotope and Fluid Inclusion Studies of Hydrothermal Ore at the Hakurei Deposit,Bayonnaise Knoll,Izu‐Bonin Arc     

Shota Watanabe  Ken‐ichiro Hayashi 《Resource Geology》2014,64(2):77-90

Sulfide and sulfate ore samples collected from the Hakurei deposit of the Bayonnaise knoll were examined for the occurrence and chemical composition of minerals, including the sulfur isotopes and the microthermometry of fluid inclusions. Massive sulfide ore, mineralized volcanic rock, and anhydrite ore occur in descending order, from the seafloor to the bottom of the cored sample. The massive sulfide ore is dominated by sphalerite and accompanied by tennantite, chalcopyrite, and pyrite with lesser amounts of galena, enargite, and covellite. Amorphous silica is commonly precipitated on the surface of the sulfide minerals. As‐bearing minerals such as tennantite, enargite, and luzonite are common, while galena and Sb‐rich tetrahedrite are scarce. The mineral abundance and chemical composition of the minerals differs from that found in chimneys of the deposit. The sulfur isotope compositions in the minerals are +3.1–5.2‰ for sulfides and +19.6–21.8‰ for sulfate minerals. The homogeneous nature of the sulfur isotopes suggests that sulfur incorporated in the Hakurei deposit came from the reduction of aqueous sulfate in seawater.  相似文献   

The Helioseismic and Magnetic Imager (HMI) Vector Magnetic Field Pipeline: SHARPs – Space-Weather HMI Active Region Patches     

M. G. Bobra  X. Sun  J. T. Hoeksema  M. Turmon  Y. Liu  K. Hayashi  G. Barnes  K. D. Leka 《Solar physics》2014,289(9):3549-3578

A new data product from the Helioseismic and Magnetic Imager (HMI) onboard the Solar Dynamics Observatory (SDO) called Space-weather HMI Active Region Patches (SHARPs) is now available. SDO/HMI is the first space-based instrument to map the full-disk photospheric vector magnetic field with high cadence and continuity. The SHARP data series provide maps in patches that encompass automatically tracked magnetic concentrations for their entire lifetime; map quantities include the photospheric vector magnetic field and its uncertainty, along with Doppler velocity, continuum intensity, and line-of-sight magnetic field. Furthermore, keywords in the SHARP data series provide several parameters that concisely characterize the magnetic-field distribution and its deviation from a potential-field configuration. These indices may be useful for active-region event forecasting and for identifying regions of interest. The indices are calculated per patch and are available on a twelve-minute cadence. Quick-look data are available within approximately three hours of observation; definitive science products are produced approximately five weeks later. SHARP data are available at jsoc.stanford.edu and maps are available in either of two different coordinate systems. This article describes the SHARP data products and presents examples of SHARP data and parameters.  相似文献   

Correction to: Microtremor array method using spatial autocorrelation analysis of Rayleigh-wave data     

Hayashi  Koichi  Asten  Michael W.  Stephenson  William J.  Cornou  Cécile  Hobiger  Manuel  Pilz  Marco  Yamanaka  Hiroaki 《Journal of Seismology》2022,26(4):629-629

Journal of Seismology -  相似文献   

Microtremor array method using spatial autocorrelation analysis of Rayleigh-wave data     

Hayashi  Koichi  Asten  Michael W.  Stephenson  William J.  Cornou  Cécile  Hobiger  Manuel  Pilz  Marco  Yamanaka  Hiroaki 《Journal of Seismology》2022,26(4):601-627

Journal of Seismology - Microtremor array measurements, and passive surface wave methods in general, have been increasingly used to non-invasively estimate shear-wave velocity structures for...  相似文献   

An image of a magma intrusion process inferred from precise hypocentral migrations of the earthquake swarm east of the Izu Peninsula   总被引：4，自引：0，他引：4  

Yoshinari Hayashi  Yuichi Morita 《Geophysical Journal International》2003,153(1):159-174

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Near-infrared imaging survey of faint companions around young dwarfs in the Pleiades cluster     

Yoichi Itoh  Yumiko Oasa  Hitoshi Funayama  Masahiko Hayashi  Misato Fukagawa  Toshio Hashiguchi  Thayne Currie 《中国天文和天体物理学报》2011,11(3)

We conducted a near-infrared imaging survey of 11 young dwarfs in the Pleiades cluster using the Subaru Telescope and the near-infrared coronagraph imager. We found ten faint point sources,with magnitudes as faint as 20 mag in the K-band,with around seven dwarfs.Comparison with the Spitzer archive images revealed that a pair of the faint sources around V 1171 Tau is very red in infrared wavelengths,which indicates very low-mass young stellar objects.However,the results of our follow-up proper motion measure...  相似文献   

Global Simulations of Differentially Rotating Magnetized Disks: Formation of Low-beta Filaments and Structured Coronae     

Machida M  Hayashi MR  Matsumoto R 《The Astrophysical journal》2000,535(1):L67-L70

We examine the excitation of oscillations in the magnetic network of the Sun through the footpoint motion of photospheric magnetic flux tubes located in intergranular lanes. The motion is derived from a time series of high-resolution G-band and continuum filtergrams using an object-tracking technique. We model the response of the flux tube to the footpoint motion in terms of the Klein-Gordon equation, which is solved analytically as an initial value problem for transverse (kink) waves. We compute the wave energy flux in upward-propagating transverse waves. In general we find that the injection of energy into the chromosphere occurs in short-duration pulses, which would lead to a time variability in chromospheric emission that is incompatible with observations. Therefore, we consider the effects of turbulent convective flows on flux tubes in intergranular lanes. The turbulent flows are simulated by adding high-frequency motions (periods 5-50 s) with an amplitude of 1 km s(-1). The latter are simulated by adding random velocity fluctuations to the observationally determined velocities. In this case, we find that the energy flux is much less intermittent and can in principle carry adequate energy for chromospheric heating.  相似文献