A Study Of The Atmospheric Boundary Layer Using Radon And Air Pollutants As Tracers

Concentrations of radon ²²²Rn andair pollutants, meteorological parametersnear the surface and vertical profiles of meteorological elements were measured atUchio (Okayama City, Okayama Prefecture, Japan) 12 km north from the coast ofthe Inland Sea of Japan. In the nighttime, the ²²²Rn concentration increased in the case of weak winds, but did not increase as much in the case of moderate or strong winds, as had been expected. In the daytime, the ²²²Rn concentrationheld at a slightly higher than average level for the period from sunrise to about 1100 JST. It is considered that this phenomenon is due to a period of morning calm, that is, a transition period from land breeze to sea breeze.NO, which is sensitive to traffic volume,brought information concerning advection.Oxidant concentrations,which reflect the availability of sunlight,acted in the reverse manner to ²²²Rnconcentrations. Thus, a set of ²²²Rn and air pollutants could provide useful information regarding the local conditions of the atmospheric boundary layer.     

Melting of forsterite Mg2SiO4 up to 15 GPa

The melting curve of forsterite has been studied by static experiment up to a pressure of 15 GPa. Forsterite melts congruently at least up to 12.7 GPa. The congruent melting temperature is expressed by the Kraut-Kennedy equation in the following form: T_m(K)=2163 (1+3.0(V₀ ? V)/V₀), where the volume change with pressure was calculated by the Birch-Managhan equation of state with the isothermal bulk modulus K₀ = 125.4 GPa and its pressure derivative K′ = 5.33. The triple point of forsterite-β-Mg₂SiO₄-liquid will be located at about 2600°C and 20 GPa, assuming that congruent melting persists up to the limit of the stability field of forsterite. The extrapolation of the previous melting data on enstatite and periclase indicates that the eutectic composition of the forsterite-enstatite system should shift toward the forsterite component with increasing pressure, and there is a possibility of incongruent melting of forsterite into periclase and liquid at higher pressure, although no evidence on incongruent melting has been obtained in the present experiment.     

Hydrostatic compression of ilmenite phase of ZnSiO3 and MgGeO3

Accurate measurements of cell parameters were performed on the ilmenite phases of ZnSiO₃ and MgGeO₃ using an X-ray diffraction method under hydrostatic conditions. The linear changes in cell parameter are represented by 1?a/a ₀=(1.06±0.04)×10^?4 P(kbar) and 1?c/c ₀=(2.11±0.04)×10^?4 P for ZnSiO₃, and 1?a/a ₀=(1.37±0.03)×10^?4 P and 1?c/c ₀=(2.05±0.04)×10^?4 P for MgGeO₃. A least-squares calculation using the first-order Birch-Murnaghan equation gives K _T =2.16±0.02 Mbar and K _T =1.87±0.02 Mbar for ZnSiO₃ and MgGeO₃, respectively. Elastic systematics assuming K _T V _m =constant give a predicted value K _T =2.14 Mbar for the ilmenite phase of MgSiO₃.     

Partitioning of heavy metals into mineral and organic fractions in a sediment core from Tokyo Bay

Sediment core was collected from Tokyo Bay. The surface enrichment of heavy metals due to human activities is recognized in the sediment. Partitioning of Cu, Zn, Fe and Mn into sulfide, carbonate, organic and silicate fractions has been determined with selective chemical leaching techniques for ²¹⁰Pb-dated sediment core samples. The heavy metal contents of silicate fractions without exchangeable sites are almost constant against depth in sediment core. However, the Cu, Zn and Mn contents of sulfide, carbonate and organic fractions vary with depth. Most Cu and Zn in the polluted sediment layer are associated with the iron sulfide fraction.     

Infrared device for simultaneous measurement of fluctuations of atmospheric carbon dioxide and water vapor

An infrared device designed to measure simultaneous fluctuations of atmospheric CO₂ and water vapor concentrations is described. The measuring frequency is 30 Hz. The sensing path length is 20 cm. It is compatible with the path length of the standard type of a sonic anemometer. The noise level of the device is equivalent to fluctuations of about 0.8 ppm peak-to-peak for CO₂ and 0.02 g kg^-1 peak-to-peak for water vapor. Field tests have showed that the device is suitable for simultaneous measurement of turbulent fluxes of CO₂ and water vapor in conjunction with a sonic anemometer.     

234Th238U radioactive disequilibrium in the surface layer of the ocean

²³⁴Th produced from ²³⁸U within sea water was found to be in radioactive disequilibrium with respect to its progenitor nuclide ²³⁸U in the surface layer of the ocean. The median value for ${}^{234}\text{Th}{}^{238}\text{U}$ activity ratio is 0.80 in the upper 200 m layer. A box-model calculation gives a removal residence time of thorium of about 0.38 yr. This suggests that ²³⁴Th is scavenged from the surface layer by the uptake of thorium by biota.     

Symmetropy of Fault Patterns: Quantitative Measurement of Anisotropy and Entropic Heterogeneity

The purpose of the effort in this paper is to show symmetropy of fault patterns. This quantity can be considered as a measure of entropic heterogeneity and anisotropy. We describe this measure based on the discrete Walsh transform. The specific results of its applications are obtained as follows. When a rock specimen undergoes creep in a laboratory experiment, the fault propagation can be monitored by the decrease of symmetropy. Moreover, in a fault model with self-organized criticality, fault patterns of critical states and subcritical states are distinguished by the behavior of the symmetropy: subcritical fault patterns show almost constant value of symmetropy but it takes various values during critical states. These results demonstrate that symmetropy idea can be used for the quantification of fault patterns.     

An Independent Method to Determine the Height of the Mixed Layer

A method for the independent evaluation ofmixed-layer (ML) height, zi, has beenproposed. The ML height is determined bythe functional relationshipszi = 0.75 z/nv max or 0.53 z/nu max in which, z is a measuring height; nv max and nu max are normalized peak frequencies of lateral velocity component, v, and longitudinal velocity component, u, spectra at height z in the surface layer respectively. Using Doppler sodar data, the technique was shown to be feasible; it is easy to apply to micro-meteorological field experiments and works even for the ML top above the range of the sodar.     

Elasticity of MgSiO3 in the ilmenite phase

The single-crystal elastic moduli of the ilmenite phase of MgSiO₃ have been determined from Brillouin spectroscopy. They are: C₁₁ = 472, C₁₂ = 168, C₃₃ = 382, C₁₃ = 70, C₄₄ = 106, C₁₄ = ?27, C₆₆ = 152 and C₂₅ = ?24 in GPa. These elastic properties are consistent with a structural mechanical model where the silicon octahedra are very stiff under compression and shear. This latter property yields an unexpectedly high shear modulus for the magnesium silicate ilmenite as compared with analogue compounds. The further transformation to perovskite will probably be associated with a significant increase in elastic properties since the strong silicon polyhedra form a structural network in this phase. The transformation of spinel and stishovite to ilmenite is associated with a slight density increase and a slight decrease in acoustic velocities. This transformation will probably not produce a seismic discontinuity even if it does occur in the Earth's mantle.     

The budget of carbon dioxide variance in the surface layer over vegetated fields

The budget equation for carbon dioxide variance can be represented by production, dissipation and flux divergence terms. Each term is measured under near neutral to moderately unstable conditions over vegetated fields. The flux divergence term is about an order of magnitude smaller than production and dissipation terms, though it shows a loss for 0.006 < _v < 1 and a gain for 1 < - _v < 10. Here, _v is the Monin-Obukhov stability parameter including humidity effect. As expected from a closure of the budget, the nondimensional production and dissipation terms are basically identical and represented by the same functional form: (1–16 _v )^–1/2.