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61.
S. Yonemura S. Kawashima H. Matsueda Y. Sawa S. Inoue H. Tanimoto 《Theoretical and Applied Climatology》2008,92(1-2):47-58
Summary The application of principal components and cluster analysis to vertical ozone concentration profiles in Tsukuba, Japan, has
been explored. Average monthly profiles and profiles of the ratio between standard deviation and the absolute ozone concentration
(SDPR) of 1 km data were calculated from the original ozone concentration data. Mean (first) and gradient (second) components
explained more than 80% of the variation in both the 0–6 km tropospheric and 11–20 km troposphere–stratosphere (interspheric)
layers. The principal components analysis not only reproduced the expected inverse relationship between mean ozone concentration
and tropopause height (r
2 = 0.41) and that in the tropospheric layer this is larger in spring and summer, but also yielded new information as follows.
The larger gradient component score in summer for the interspheric layer points to the seasonal variation of the troposphere–stratosphere
exchange. The minimum SDPR was at about 3 km in the tropospheric layer and the maximum was at about 17 km in the interspheric
layer. The tropospheric SDPR mean component score was larger in summer, possibly reflecting the mixing of Pacific maritime
air masses with urban air masses. The cluster analysis of the monthly ozone profiles for the 1970s and 2000s revealed different
patterns for winter and summer. The month of May was part of the winter pattern in the 1970s but part of the summer pattern
during the 2000s. This statistically detected change likely reflects the influence of global warming. Thus, these two statistical
analysis techniques can be powerful tools for identifying features of ozone concentration profiles.
Authors’ addresses: S. Yonemura, S. Kawashima, S. Inoue, National Institute for Agro-Environmental Sciences, 3-1-3 Kannondai,
Tsukuba, Ibaraki 305-0031, Japan; H. Matsueda, Y. Sawa, Meteorological Research Institute, 1-1 Nagamine, Tsukuba, Ibaraki
305-0052, Japan; H. Tanimoto, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506, Japan. 相似文献
62.
Toshiro Tanimoto 《Geophysical Journal International》1997,129(2):305-310
Effects of sphericity are commonly ignored in the lithospheric bending problem. In order to examine its effects, I solve a simple axisymmetric spherical-shell model. The full solution and the asymptotic solution are derived from the basic equations, and their relationship to the flat-plate solution is examined. For displacement, effects of sphericity are small, and use of the flat-plate solution produces results that are numerically indistinguishable from those of the spherical solution. The most significant effect of sphericity appears in the stress, in particular the normal stress along the strike direction of the trench. This stress is approximately given by Eur /R , where E is Young's modulus, ur is the vertical deformation of the shell and R is its radius of curvature. If the shell (lithosphere) is bent downwards and reaches 30 km, this stress can become about 5 kbar in the Earth. While plastic behaviour may set in under such high pressure conditions and analysis beyond elasticity theory may be required, sphericity may be a cause of large compressive stress in the trench strike direction. This stress may play an important role in forming the overall shape of the Earth's subduction zones. 相似文献
63.
The beam attenuation coefficient, organic carbon (POC) and organic nitrogen (PON) contents of suspended materials in Etauchi
Bay, which has little inflow of river water as well as very weak tidal current (maximum speed: 6.5cm·sec−1), were measured as a function of depth for all seasons to understand a seasonal variation of bottom turbidity layer. In spring
and summer, the beam attenuation coefficient in bottom layer and POC and PON contents of suspended materials in the surface
water layer increased with time, which brought the occurrence of the bottom turbidity layer. From autumn to winter, however,
their concentrations became low and constant over the whole depth almost independent of time. As a result, the bottom turbidity
layer disappeared in winter and beam attenuation coefficient became constant over the whole depth. From these results, it
may be considered that the bottom turbidity layer was produced by phytodetritus brought from surface water layer, rather than
by resuspension of bottom sediment in Etauchi Bay. 相似文献
64.
Regeneration of silicate in the Japan Sea, an example of semi-closed sea, was studied. In the Japan Sea Proper Water the apparent regenerative ratio of the nutrients was determined to be:O C N P Si=–289 (116)14.3181.It was assumed that the dissolved silicate present in sea water is grouped into three fractions; 1)preformed silicate of conservative nature, 2)oxidative silicate which dissolves in oxidation process of organisms with consumption of oxygen, and 3)non-oxidative silicate which dissolves without oxygen consumption. The dissolution rate ofnon-oxidative silicate in the Japan Sea Proper Water was estimated to be 0.07g-at. Si/l/yr from the data ofAOU values and assumed rates of oxygen consumption. This dissolution rate ofnon-oxidative silicate agreed with that obtained in the deep Pacific by the vertical advection diffusion model byKido andNishimura (1972). 相似文献
65.
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68.
Toshiro Tanimoto 《Geophysical Journal International》1995,121(1):103-110
A simple modification of the waveform inversion formula, based on the normal mode perturbation theory, is shown to lead to a formula for traveltime anomalies. The kernel which is derived can be used for traveltime inversion with automatic inclusion of finite frequency effects. Inversion for Earth structure with such kernels will lead to better resolution estimates than ray-theoretical traveltime inversion. Examples of kernels for transverse component seismograms are shown for direct S waves, ScS , Love waves and diffracted S waves. A measure of finite frequency effects is also proposed by comparing our formula with the one from ray theory. A quantity which should be 1 in the case of ray theory is computed for the finite frequency kernels and is shown to have deviations up to about 30 per cent from 1. Therefore, the use of ray theory for long-period body waves applies incorrect weight along a ray path and may introduce a small bias to an earth model. 相似文献
69.
Takayuki Shiozawa Kichiichiro Kawana Akira Hoshika Terumi Tanimoto Osamu Takimura 《Journal of Oceanography》1977,33(6):350-356
From July to November, the thermocline which has strong temperature gradient (0.7C m–1) is formed in the bottom water of Beppu Bay, and it prevents the downward mixing of surface water. This has caused the bottom water of the basin to become depleted in oxygen, and in November the bottom water below about 60 m depth becomes anoxic. Accordingly manganese and iron are reduced and more soluble under the anoxic condition, those concentrations are high relative to surface water, and the maximums are 1,240g l–1 and 80g l–1. Under the anoxic condition, the flux of dissolved manganese from the sediment is about 10g cm–2 day–1. 相似文献
70.
Large earthquake-induced displacements of a bridge abutment can occur, when the bridge is built on a floodplain or reclaimed area, i.e., liquefiable ground, and crosses a water channel. Seismic responses of a bridge abutment on liquefiable ground are the consequence of complex interactions between the abutment and surrounding soils. Therefore identification of the factors dominating the abutment response is important for the development of simplified seismic design methods. This paper presents the results of dynamic three-dimensional finite element analyses of bridge abutments adjacent to a river dike, including the effect of liquefaction of the underlying ground using earthquake motions widely used in Japan. The analysis shows that conventional design methods may underestimate the permanent abutment displacements unless the following two items are considered: (1) softening of the soil beneath the liquefiable layer, due to cyclic shearing of the soil surrounding the piles, and (2) the forces acting on the side faces of the abutment. 相似文献