Distribution of Biogenic Silica Content in Surface Sediments from the Southern South China Sea and Its Environmental Dignificance

Biogenic silica content was determined in 25 surface sediment samples from the southern South China Sea to study its distribution and its modern oceanic environmental significance, which may provide further scientific evidence for paleoceanography explaination. This study showed that biogenic silica content in surface sediments and its water depth have evidently positive correlation, and the correlation coefficient was up to 0.782. Biogenic silica content was very low in continental shelf shallows and could not reflect the productivity of siliceous micropaleontology in surface waters, which may be affected by sedimentary types and terrigenous matter dilution. Distribution of biogenic silica content in surface sediments from deep water areas showed that it could not only reflect the paleoproductivity of siliceous micropaleontology in surface waters, but also indicate the strong or feeble upwelling. Thus, it was further confirmed that using biogenic silica content in sediments to trace upwelling and its change was effective and reliable. The analyzed result showed that radiolariia and poriferous specula have more contribution for biogenic opal, comparing with diatom in surface sediments from the northern studied area, probably owing to the diatom dissolved easily away and eaten by other organisms with little effort. In the upwelling areas, radiolarian, diatom and poriferous specula all approximately showed high abundance, which was consistent with high biogenic silica content.

高速公路沥青混凝土路面结构设计与质量控制

从原材料的选择、配合比的调整、设计与验证介绍了沥青混凝土上面层的配合比设计，并对其关键施工技术作了论述，最终保证高速公路沥青混凝土路面的工程质量。

Model on surface borehole squeezing deformation fracture

As a good method to solve the problem of high methane on the workface and inthe goaf,drawing coal strata methane through a surface borehole is used.However,theexcavation affected the overlying rock strata greatly.When the excavation face passedthrough the surface borehole position,the surface borehole fractures fast.This problemwas seriously related to the unformed squeeze effect.Therefore,a squeezing deformationfracture model based on the rock strata squeezing effect was set up.At the same time,a3DEC simulation model is presented to confirm the theory.The result shows that the modelis reliable and has a good engineering application value.

The effect of current and wave on whitecap coverage via relative speed:the Atlantic Ocean case

Whitecapping plays an important role in many air-sea exchange and upper ocean processes.Traditionally,whitecap coverage is parameterized as a function of wind speed only.At present,the relative speed of ocean current to wind is considered to be important in the air-sea exchange parameterization which is the function of wind speed only.In this paper,the effects of ocean surface velocity (current velocity and wave induced velocity) and the wave parameters on whitecap coverage through relative speeds are investigated,by applying a 2-parameter whitecap coverage model to the Atlantic Ocean.It is found that the impacts of both current and wave on whitecap coverage are considerable in the most part of the Atlantic Ocean.It is interesting that the effect of wave is more significant than that of current.

Distinguished Effects of Interannual Salinity Variability on the Development of the Central-Pacific El Ni o Events

El Nio events in the central equatorial Pacific (CP) are gaining increased attention,due to their increasing intensity within the global warming context.Various physical processes have been identified in the climate system that can be responsible for the modulation of El Nio,especially the effects of interannual salinity variability.In this work,a comprehensive data analysis is performed to illustrate the effects of interannual salinity variability using surface and subsurface salinity fields from the Met Office ENSEMBLES (EN3) quality controlled ocean dataset.It is demonstrated that during the developing phase of an El Nio event,a negative sea surface salinity (SSS) anomaly in the western-central basin acts to freshen the mixed layer (ML),decrease oceanic density in the upper ocean,and stabilize the upper layers.These related oceanic processes tend to reduce the vertical mixing and entrainment of subsurface water at the base of the ML,which further enhances the warm sea surface temperature (SST) anomalies associated with the El Nio event.However,the effects of interannually variable salinity are much more significant during the CP-El Nio than during the eastern Pacific (EP) El Nio,indicating that the salinity effect might be an important contributor to the development of CP-El Nio events.

Impact of sea spray on upper ocean temperature during typhoon passage:simulation with a 1-D turbulent model

At the interface between the lower atmosphere and sea surface,sea spray might significantly influence air-sea heat fluxes and subsequently,modulate upper ocean temperature during a typhoon passage. The effects of sea spray were introduced into the parameterization of sea surface roughness in a 1-D turbulent model,to investigate the effects of sea spray on upper ocean temperature in the Kuroshio Extension area,for the cases of two real typhoons from 2006,Yagi and Soulik. Model output was compared with data from the Kuroshio Extension Observatory(KEO),and Reynolds and AMSRE satellite remote sensing sea surface temperatures. The results indicate drag coefficients that include the spray effect are closer to observations than those without,and that sea spray can enhance the heat fluxes(especially latent heat flux) considerably during a typhoon passage. Consequently,the model results with heat fluxes enhanced by sea spray simulate better the cooling process of the SST and upper-layer temperature profiles. Additionally,results from the simulation of the passage of typhoon Soulik(that passed KEO quickly),which included the sea spray effect,were better than for the simulated passage of typhoon Yagi(that crossed KEO slowly). These promising 1-D results could provide insight into the application of sea spray in general circulation models for typhoon studies.

基于机能持久性的沥青路面上中表层材料设计分析探究

本研究从大修设计需求岀发,对基于机能持久性的沥青路面上中表层材料设计课题开展专题分析探究,探讨大修沥青路面上表层和中表层设计初选方案,以为同类沥青路面工程应用提供研究和技术参考,助力建设机能持久性的沥青公路路面。

An improved diagnostic stratocumulus scheme based on estimated inversion strength and its performance in GAMIL2

Based on satellite data and the estimated inversion strength(EIS) derived by Wood et al.(2006), a feasible and uncomplicated stratocumulus scheme is proposed, referred to as EIS scheme. It improves simulation of cloud radiative forcing(CRF) in the Grid-point Atmospheric Model of IAP/LASG version 2(GAMIL2.0) model. When compared with the original lower troposphere stability(LTS) scheme, the EIS scheme reproduces more reasonable climatology distributions of clouds and CRF. The parameterization partly corrects CRF underestimation at mid and high latitudes and overestimation in the convective region. Such improvements are achieved by neglecting the effect of free-tropospheric stratification changes that follow a cooler moist adiabat at middle and high latitude, thereby improving simulated cloudiness. The EIS scheme also improves simulation of the CRF interannual variability. The positive net CRF and negative stratiform anomaly in the East Asian and western North Pacific monsoon regions(EAWNPMR) are well simulated. The EIS scheme is more sensitive to sea surface temperature anomalies(SSTA) than the LTS. Therefore, under the effect of a warmer SSTA in the EAWNPMR, the EIS generates a stronger negative stratiform response, which reduces radiative heating in the low and mid troposphere, in turn producing strong subsidence and negative anomalies of both moisture and cloudiness. Consequent decreases in cloud reflection and shading effects ultimately improve simulation of incoming surface shortwave radiative fluxes and CRF. Because of the stronger subsidence, a stronger anomalous anticyclone over the Philippines Sea is simulated by the EIS run, which leads to a better positive precipitation anomaly in eastern China during ENSO winter.