A Scheme for Objective Analysis of Wind Field Incorporating Multi-Weighting Functions in the Optimum Interpolation Method

A method of objective analysis scheme having three different weighting functions for different conditions of the wind flow has been developed for the Indian region, two of which are anisotropic and third one is isotropic. Basically Gandin’s Optimum Interpolation method is used. The “effective” distance between a grid point and observation point used for the anisotropic functions, has been applied to calculate weighting functions following Benjamin and Seaman (1985) and objective analyses were made at the 700 hPa level for three consecutive days from 6 July to 8 July 1979. The quantitative evaluation of the objectively analysed fields have been made by computing the R.M.S. errors. Ana-lyses obtained using multi-weighting functions (anisotropic) and those obtained using ordinary circular functions (isotropic-Gandin, 1963) have been compared. Also, the centres of the monsoon depressions obtained by this method have been compared with those of subjective analyses.     

A Possible Periodicity in the Radio Light Curves of 3C 454.3

During the period 1966.5–2006.2 the 15GHz and 8GHz light curves of 3C 454.3 (z = 0.859) show a quasi-periodicity of ～12.8 yr (～6.9 yr in the rest frame of the source) with a double-bump structure. This periodic behaviour is interpreted in terms of a rotating double-jet model in which the two jets are created from the black holes of a binary system and rotating with the period of the orbital motion. The periodic variations in the radio fluxes of 3C 454.3 are suggested to be mainly due to the lighthouse effects (or the variation in Doppler boosting) of the precessing jets caused by the orbital motion. In addition, variations in the rate of mass accreting onto the black holes may be also involved.     

Changes of taxonomical composition of Late Jurassic-Early Cretaceous palynofloras of Bureya Basin,Russia

The changes of taxonomical composition of the Late Jurassic-Early Cretaceous palynofloras are revealed,in the upper stream of Bureya River in Bureya Basin.The palynofloras are dominated as follows:the Berriasian one by ferns(Cyatheaceae,Dicksoniaceae,Osmundaceae),Classopollis and bisaccate pollen;the Valanginian-Hauterivian one by ferns(Cyatheaceae,Dicksoniaceae),Ginkgocycadophytus and bisaccate pollen;the Barremian one by ferns(Cyatheaceae,Dicksoniaceae);the Aptian one by ferns(Cyatheaceae,Dicksoniaceae,Gleicheniaceae) and Ginkgocycadophytus;and the Albian one by ferns(Schizaeaceae) and bisaccate pollen.In the Albian the floral diversity raises with the angiosperms appearing.     

地震机制和板块构造

引言在对固体地球多数大尺度过程的思考时板块构造概念框架的应用和我们对板块构造的现今理解深化中,天然地震学承担了重要角色。板块构造说神奇般的发展中,根据Uyeda(1978,2002)、Cox(1973)、Menard(1986)的观点,地震分布对板块边界和它们的运动提供了某些最强有力的证据(如,I     

Intergrain contact density indices for granular mixes I： Framework

Mechanical behavior such as stress-strain response, shear strength, resistance to liquefaction, modulus, and shear wave velocity of granular mixes containing coarse and fine grains is dependent on intergrain contact density of the soil. The global void ratio e is a poor index of contact density for such soils. The contact density depends on void ratio, fine grain content （Cv）, size disparity between particles, and gradation among other factors. A simple analysis of a two-sized particle system with large size disparity is used to develop an understanding of the effects of Cv, e, and gradation of coarse and fine grained soils in the soil mix on intergrain contact density. An equivalent intergranular void ratio （ec）oq is introduced as a useful intergrain contact density for soils at fines content of less than a threshold value Crth. Beyond this value, an equivalent interfine void ratio （ef）eq is introduced as a primary intergrain contact density index. At higher values of Cv beyond a limiting value of fine grains content CVL, an interfine void ratio ef is introduced as the primary contact density index. Relevant equivalent relative density indices （Drc）eq and （Drf）eq are also presented. Experimental data show that these new indices correlate well with steady state strength, liquefaction resistance, and shear wave velocities of sands, silty sands, sandy silts, and gravelly sand mixes.     

Are water tables a subdued replica of the topography?

The water table in unconfined aquifers is often believed to be a subdued replica of the topography or land surface. However, this assumption has not been widely tested and in some cases has been found to be in error. An analysis of ground water rise in regional unconfined aquifers, using both a two-dimensional boundary element model and a one-dimensional Dupuit-Forchheimer model, reveals the conditions under which the water table does or does not closely follow the topography. A simple decision criterion is presented to estimate in advance under which conditions the water table is expected to be largely unrelated to the topography and under which conditions the topography controls the position of the water table.     

Fate of DDT-related compounds in Bohai Bay and its adjacent Haihe Basin, North China

Concentrations of ten DDTs (2,2-bis-(chlorophenyl)-1,1,1-trichloroethane) of which p,p'-DDA (2,2-bis(chlorophenyl)acetic acid), p,p'-DDM (bis(chlorophenyl)methane) and p,p'-DBP (dichlorobenzophenone) are often neglected, were measured in 25 water and 25 sedimentary samples from Bohai Bay and its adjacent Haihe Basin. The ratio of o,p'-DDX/p,p'-DDX in the upper reaches of Yongdingxin River ranged from 0.71 to 2.44, suggesting that the potential source of pollution would be the manufacturing or use of dicofol near this river. While DDA accounted for 52-93% of the SigmaDDT concentration in water, DDA was only detected in three sedimentary samples. And DDM was found to be an important degradation product of DDT in water following DDA. It should be noted that DBP (0.60-3.30 ng/g) is a major metabolite comparable with DDE (2,2-bis(chlorophenyl)-1,1-dichloroethylene, nondetectable-1.80 ng/g) and DDD (2,2-bis-(chlorophenyl)-1,1-dichloroethane, nondetectable-2.86 ng/g) in sediment in Bohai Bay. Finally, the SigmaDDT concentration in sedimentary sample from Bohai Bay was found to be dependent on the TOC (total organic carbon) value.