Interannual variability of latent and sensible heat fluxes in the South China Sea

The South China Sea (SCS) is significantly influenced by El Niño and the Southern Oscillation (ENSO) through ENSO-driven atmospheric and oceanic changes. We analyzed measurements made from 1960 to 2004 to investigate the interannual variability of the latent and sensible heat fluxes over the SCS. Both the interannual variations of latent and sensible heat fluxes are closely related to ENSO events. The low-pass mean heat flux anomalies vary in a coherent manner with the low-pass mean Southern Oscillation Index (SOI). Time lags between the heat flux anomalies and the SST anomalies were also studied. We found that latent heat flux anomalies have a minimum value around January of the year following El Niño events. During and after the mature phase of El Niño, a change of atmospheric circulation alters the local SCS near-surface humidity and the monsoon winds. During the mature phase of El Niño, the wind speed decreases over the entire sea, and the air-sea specific humidity difference anomalies decreases in the northern SCS and increases in the southern SCS. Thus, a combined effect of wind speed anomalies and air-sea specific humidity difference anomalies results in the latent heat flux anomalies attaining minimum levels around January of the year following an El Niño year.     

Impacts of internal waves on chlorophyll a distribution in the northern portion of the South China Sea

Internal waves can bring nutrients to the upper level of water bodies and facilitate phytoplankton photosynthesis. Internal waves occur frequently in the northern portion of the South China Sea and inflict an important effect on chlorophyll a distribution. In this study, in-situ observation and satellite remote sensing data were used to study the effects of internal waves on chlorophyll a distribution. Based on the in-situ observations, lower chlorophyll a concentrations were present in the middle and bottom level in areas in which internal waves occur frequently, while the surface chlorophyll a distribution increased irregularly, and a small area with relatively higher chlorophyll a concentrations was observed in the area around the Dongsha Island. Satellite remote sensing showed that the chlorophyll a concentration increased in the area near Dongsha Island, where internal waves frequently occurred. The results of the increased chlorophyll a concentration in the surface water near Dongsha Island in the northern portion of the South China Sea indicated that internal waves could uplift phytoplankton and facilitate phytoplankton growth.     

Gene cloning and prokaryotic expression of recombinant flagellin A from Vibrio parahaemolyticus

The Gram-negative Vibrio parahaemolyticus is a common pathogen in humans and marine animals. Bacteria flagellins play an important role during infection and induction of the host immune response. Thus, flagellin proteins are an ideal target for vaccines. We amplified the complete flagellin subunit gene (flaA) from V. parahaemolyticus ATCC 17802. We then cloned and expressed the gene into Escherichia coli BL21 (DE3) cells. The gene coded for a protein that was 62.78 kDa. We purified and characterized the protein using Ni-NTA affinity chromatography and Anti-His antibody Western blotting, respectively. Our results provide a basis for further studies into the utility of the FlaA protein as a vaccine candidate against infection by Vibrio parahaemolyticus. In addition, the purified FlaA protein can be used for further functional and structural studies.     

热弹性P波在有流体夹层介质中的传播问题及其基本特征*

本文作为基础理论研究,讨论了热弹性P波在有流体夹层介质中的传播问题。研究结果表明:热弹性波在流体夹层的传播中,不仅存在反射波、透射波,而且,还伴随有具有相同传播速度的温度波;且其反射系数、透射系数均为复数,并与介质的物性参数及夹层厚度有关。同时指出反射波、透射波的振幅、位相均受介质的物性参数及夹层厚度的影响。此外,还表明夹层中往返震荡的层间波是一系列正传热弹性波和反传热弹性波的叠加。     

气枪震源弱信号提取的可靠性初步分析

基于数据合成仿真、气枪震源激发信号的实际处理,由叠加信噪比、波形相关系数及相位偏移等3个定量指标,系统评价线性、相位加权和S变换等3种叠加方法提取强背景噪声下弱信号的实际性能,并定量估计叠加结果的可靠性。通过对以上3种方法叠加结果的综合探讨,初步对比分析后认为,线性叠加虽然信噪比较低,但波形畸变最小;相位加权叠加信噪比较高,相位偏移小,但波形质量与线性叠加的结果相比偏离较大;S变换叠加可获得相对较高的信噪比,波形幅度损失小,但存在一定的相位偏移现象。因此建议,当波形质量和时间精度均要求较高时宜用线性叠加。但气枪震源激发有限时选择叠加方法应有所偏重,若要求波形高保真,宜选择S变换叠加;若要求时间高精度,可选择相位加权叠加方法,以合理实现弱信号的有效提取。     

Contribution of climatic and technological factors to crop yield: empirical evidence from late paddy rice in Hunan Province,China

Climatic and technological factors are two remarkable aspects that are thought to contribute to crop yield change. However, the most significant factors and their contribution rate remain debatable. Selecting Hunan Province, which is one of the largest paddy rice producing regions in China as the research area, the marginal contributions of climatic and technological factors to late paddy yield change are estimated using a county-level panel data regression model with explicit consideration of technological variables during 2000–2011. The results indicate that the mean daily temperature and adoption rate of hybrid rice have significant positive impacts on late paddy rice yield. During the research period, 1 °C temperature increase will cause 7.220 t/km² increase in late paddy rice yield, and 1 % increase in the adoption rate of hybrid rice will cause 0.212 t/km² increase. Climatic factors, especially their annual variability, exhibit a stronger overall linkage to changes in late paddy rice yield in the study area compared with the technological factors. Climatic factors accounted for 67.645 and 74.585 % of the trend and variability in late paddy rice yield, respectively. The results of this study can provide valuable information for stakeholders to adjust the input on late paddy rice production and better adapt to the effect of climate change.     

Hydration effects on crystal structures and equations of state for silicate minerals in the subducting slabs and mantle transition zone

There are potentially huge amounts of water stored in Earth’s mantle, and the water solubilities in the silicate minerals range from tens to thousands of part per minion (ppm, part per million). Exploring water in the mantle has attracted much attention from the societies of mineralogy and geophysics in recent years. In the subducting slab, serpentine breaks down at high temperature, generating a series of dense hydrous magnesium silicate (DHMS) phases, such as phase A, chondrodite, clinohumite, etc. These phases may serve as carriers of water as hydroxyl into the upper mantle and the mantle transition zone (MTZ). On the other hand, wadsleyite and ringwoodite, polymorphs of olivine, are most the abundant minerals in the MTZ, and able to absorb significant amount of water (up to about 3 wt.% H₂O). Hence, the MTZ becomes a very important layer for water storage in the mantle, and hydration plays important roles in physics and chemistry of the MTZ. In this paper, we will discuss two aspects of hydrous silicate minerals: (1) crystal structures and (2) equations of state (EoSs).     

新丰江地区地壳P波三维速度结构及活动构造研究

利用震源位置和速度结构的联合反演得到2007年6月~2014年7月新丰江地区地震序列的震源位置及P波三维速度结构模型,并进一步对比区域活动构造的产状特征及震源机制解等。结果显示,自ES向WN新丰江库区断裂深度有逐渐增大的趋势,与重力场的研究结果一致。库区大坝至东源锡场之间的中-上地壳存在4个大小不等的高速体,其中,锡场下方的高速体Ⅰ体积最大(EW向截面约6km×7km),速度最大,中心速度达6.3km/s。库区大坝下方存在以人字石断裂(F2)、南山-坳头断裂(F4)、河源断裂(F1)、石角-新港-白田断裂(F5)等为中心的强烈构造变形区,1960年至今大坝下方高速体Ⅲ、Ⅳ边缘已发生包括1962年6.1级地震在内的7次ML≥5.0地震,能量释放较为彻底;锡场下方高速体Ⅰ的边缘自2012年以来中小地震活跃,且b值较低,不排除发展为中强震孕震凹凸体的可能。     

辽宁建昌玲珑塔地区中侏罗世地层与化石初步报道

辽西建昌县玲珑塔地区出露一套火山岩所夹的沉积地层, 富含叶肢介、介形类、双壳类、鱼、昆虫、脊椎动物和植物等化石。经区域地层研究, 结合对玲珑塔大西山地质剖面实测以及对该剖面新近所采集的各门类化石的综合研究, 确认此套沉积地层位于义县组之下, 属髫髻山组, 化石显示“燕辽生物群”面貌, 时代为中侏罗世。