Amino acids in equatorial Pacific Ocean water

Seawater samples from the Eastern Equatorial Pacific Ocean were analyzed for amino acids by a ligand-exchange chromatography technique. The results showed that dissolved free amino acids make up only 0.3% of DOC, much less than has been previously reported for open ocean waters. Substantially larger amounts of combined amino acids are present, however. Concentration variations of the combined amino acid fraction in the water column suggest their potential use as a water mass indicator.     

Diurnal variations in planetary boundary-layer winds over land

Windsonde data gathered over a nine-year period at three stations in the Southeast U.S. are stratified by season and by time of observation to provide average profiles depicting the diurnal variations in low-level winds. Significant variations are found (especially during the summer months) in wind speed, angle between wind direction and isobars, and the various terms of the kinetic energy budget equation. A qualitative model of the diurnal variations in planetary boundary-layer winds (over land) is developed. From a thesis submitted to the Graduate Faculty of Colorado State University in partial fulfillment of the requirements for the degree, Doctor of Philosophy.     

雷达信号的相关分析和谱分析

运动质点的多普勒效应使它们散射的雷达信号呈现为一种随机过程,对这随机过程的统计特性进行分析就能够推断云和降水的微物理或运动学的状况。本文由这种观点讨论了雷达气象的几种测量原理,它能够比较清楚地阐明每种方法的实质,也便于对各种方法的优缺点进行对比。文中还讨论了脉冲波列的谱分析问题,涉及了如何根据雷达测量结果去推断云和降水的微物理或运动学状况的问题。     

一个大气扩散的梯度-传输理论模式及其应用

本文在u=u(z),k_y=k_y(x,z),k_z=k_z(x,z)及考虑下垫面对浓度场有清除作用的前提下,求解了定常连续点源三维湍流扩散方程,得到浓度场的分析解。解中含有随稳定度而变的参数。应用Project Prairie Grass的地面源试验资料,经验地定出了从中等不稳定到中等稳定时适用于小尺度扩散的有关参数。将本模式用来计算上述试验中的浓度,除较少的例外情况外,个例的计算浓度与实验浓度的相对误差平均在200％以内,并对误差原因进行了讨论。最后对下垫面影响的不同大小计算了清除作用对地面源浓度场的影响。     

Spheroidal pyroxenite aggregates in the Bushveld Complex — a special case of silicate liquid immiscibility

Spherical aggregates of orthopyroxene are reported from some parts of the Bushveld Complex in a variety of host rocks.Detailed mapping has shown that these spherical aggregates, comprising pyroxenite spheroids in a quartz-norite matrix, are contact phenomena and not stratigraphic markers. Orthopyroxene, biotite and amphibole are enriched in spheroids relative to matrix; their mineral chemistry showing a fairly constant orthopyroxene and plagioclase composition through the spheroids and into the matrix, indicating in-situ formation.Bulk chemistry shows spheroid to matrix tie-lines orthogonal to those generally accepted for silicate liquid immiscibility, but other chemical information is consistent with the occurrence of immiscibility.The formation of the aggregates may be related to the industrial process of spherical agglomeration, by which spheroids are formed by the introduction of an immiscible “bridging liquid” to the melt — probably derived from the floor rocks in this case. The mechanism accounts for the field relationships, petrography and chemistry of the aggregate-matrix system. The petrology of the process equates with a special case of silicate liquid immiscibility induced by local contamination and ageing of the original magma.A similar “bridging liquid” mechanism could also account for the formation of the so-called “boulder bed” beneath the Merensky Reef.     

Axisymmetric seismic response of a thick circular plate supporting many rods by modal synthesis

Dynamic response of a thick, horizontal, circular plate supporting a large number of slender rods subjected to uniform boundary motion in the vertical direction has been studied by synthesizing component modes of continuous substructures. The excitation considered corresponds to the vertical component of boundary movement produced by earthquake disturbances and the axisymmetric response problem was solved. Mindlin theory was used to formulate the component equations of the plate which is treated as the main component in a modal synthesis technique. The slender rods, which are attached vertically to the plate, are handled as branch components. Vibration modes of a classical thin plate were used as the initial displacement functions for the Mindlin plate. These functions were subsequently modified by a component mode improvement process to obtain plate modes. System modes were generated by combining the improved plate modes with component modes of rods. Numerical results for the natural frequencies and time-history response of the coupled system are compared with those given by a three-dimensional finite element method.     

Pelagic tar off Georgia and Florida in relation to physical processes

Following the Ixtoc I oil rig blowout in Campeche Bay we hypothesized that resulting tarballs should eventually appear in the Gulf Stream off Gerogia and that because of dynamic barriers in the innershelf little would reach nearshore areas. To test these hypotheses, surface tows to collect floating tar were taken off the coasts of Georgia and Florida in October and December, 1979.No tar was found within 40 km of the shore. All samples more than 40 km offshore contained some tar. The mean concentration was 0.82 mg m^?2 with a range of 0.01–5.6 mg m^?2. Closely spaced sampling showed extreme variation but trends were consistent. Perylene was the most abundant compound in the tarballs.     

Ground-based FTIR Measurements with High Temporal Resolution

We outline how ground-based Fourier transform infrared (FTIR) measurements of stratospheric trace species, obtained with high temporal resolution, could be used to detect filaments of polar vortex air at mid-latitudes and therefore test high spatial resolution chemical transport models (CTMs). Vertical column abundances of HCl, ClONO2, HNO3, N2O and HF have been obtained from FTIR solar absorption measurements made throughout the day from Aberdeen, UK (57°N, 2°W) on several days during winter/spring 1993/94 and 1994/95. The short-timescale ( 2 hours) variability observed in the columns is attributed to real atmospheric variations and is often associated with the passage of high latitude air over Aberdeen. This is confirmed by 3D modelling studies which qualitatively reproduce and rationalise the observed changes in the column data on January 19 1994, January 20 1995 and February 26 1995. We describe the viewing geometry of ground-based FTIR measurements and we suggest a measurement strategy which should maximise the information retrieved on horizontal gradients in stratospheric trace species columns from FTIR measurements.     

Retrieval single-doppler radar wind with variational assimilation method-part i: objective selection of functional weighting factors

In variational problem, the selection of functional weighting factors (FWF) is one of the key points for discussing many relevant studies. To overcome arbitrariness and subjectivity of the empirical selecting methods used widely at present, this paper tries to put forward in optimal objective selecting method of FWF. The focus of the study is on the weighting factors optimal selection in the variation retrieval single-Doppler radar wind field with the simple adjoint models. Weighting factors in the meaning of minimal variance are calculated out with the matrix theory and the finite difference method of partial differential equation. Experiments show that the result is more objective comparing with the factors obtained with the empirical method.