Transition from platemargin to intraplate environment: Geochemistry of basalts in Paleogene Liaohe basin,northeastern China

Mesozoic and Cenozoic volcanic rocks are widely distributed in the circum-Pacific area of eastern China. These rocks have long been genetically linked to westward subduction of the paleo-Pacific oceanic plate to the eastern Asia continent[1,2]. Research in re-cent years[3―6] has attained conclusions that a simple paleo-Pacific subduction model does not work well in interpreting all the volcanic rocks in eastern China, although some of them could be attributed to circum-Pacific interaction …     

Unstable Dynamical Properties of Spiral Cloud Bands in Tropical Cyclones

A nondivergent barotropic model （Model 1） and a barotropic primitive equation vortex model （Model 2） are linearized respectively in this paper. Then their perturbation wave spectrums are computed with a normal mode approach to study the instability problem on an appointed tropical cyclone （TC）-like vortex, thereby, the dynamic instability properties of spiral cloud bands of TCs are discussed. The results show that the unstable mode of both models exhibits a spiral band-like structure that propagates away from the vortex outside the radius of maximum winds. The discrete modal instability of the pure vortex Rossby wave can account for the generation of the eyewall and the inner spiral band. The unstable mode in Model 2 has three parts, i.e., eyewall, inner and outer spiral bands. This mode can be interpreted as a mixed vortex Rossby-inertia gravitational wave. The unbalanced property of the wave outside the stagnation radius of the vortex Rossby wave is one of the important reasons for the formation of the outer spiral band in TCs. Accordingly, the outer spiral band can be identified to possess properties of an inertial-gravitational wave. When the formation of unstable inner and outer spiral bands is studied, a barotropic vortex model shall be used. In this model, the most unstable perturbation bears the attributes of either the vortex Rossby wave or the inertial-gravitational wave, depending on the vortex radius. So such perturbations shall be viewed as an unbalanced and unstable mixed wave of these two kinds of waves.     

Variation of Radio Refractivity with Respect to Moisture and Temperature and Influence on Radar Ray Path

In this study, the variation of radio refractivity with respect to temperature and moisture is analyzed. Also, the effects of vertical gradients in temperature and moisture on the propagation paths of electromagnetic waves of weather radar are examined for several sites across the United States using several years of sounding data from the National Weather Service. The ray path is important for identifying storm characteristics and for properly using the radar data in initializing numerical weather prediction models. It is found that during the warm season the radio refractivity gradient is more sensitive to moisture gradients than to temperature gradients. Ray paths from the commonly accepted vertical ray path model are compared to a ray path computed from a stepwise ray tracing algorithm using data from actual soundings. For the sample of about 16 000 soundings examined, we find that only a small fraction of the ray paths diverge significantly from those calculated using a ray path model based on the US Standard Atmosphere. While the problem of ray dueting in the presence of a temperature inversion is fairly well known, we identify the presence of a strong vertical moisture gradient as the culprit in the majority of the cases where significant deviations occurred.     

风暴尺度天气下利用集合卡尔曼滤波模拟多普勒雷达资料同化试验I.不考虑模式误差的情形

本文在假定模式无偏差的情况下, 利用一次风暴过程的模拟多普勒雷达资料进行一系列风暴天气尺度的集合卡尔曼滤波资料同化试验, 检验集合卡尔曼滤波在风暴天气尺度资料同化方面的效果, 并验证各集合卡尔曼滤波参数对同化效果的影响。试验结果表明, 集合卡尔曼滤波能有效地应用于风暴尺度的资料同化; 40个集合成员以及6 km的局地化尺度能较好地滤除采样误差造成的虚假相关, 同时可以将观测信息传递到无观测的模式格点; 利用背景场加上空间平滑的高斯型随机扰动生成初始成员的方式较未经过平滑的方式有更好的分析效果; 背景场扰动方法能够提高样本的离散度; 只同化反射率的同化试验表明, 反射率的同化效果较明显, 也证明了集合卡尔曼滤波在非常规资料同化中的作用; 增加径向风资料同化的效果优于只进行反射率同化的结果。     

风暴尺度天气下利用集合卡尔曼滤波模拟多普勒雷达资料同化试验Ⅰ.不考虑模式误差的情形

本文在假定模式无偏差的情况下,利用一次风暴过程的模拟多普勒雷达资料进行一系列风暴天气尺度的集合卡尔曼滤波资料同化试验,检验集合卡尔曼滤波在风暴天气尺度资料同化方面的效果,并验证各集合卡尔曼滤波参数对同化效果的影响。试验结果表明,集合卡尔曼滤波能有效地应用于风暴尺度的资料同化;40个集合成员以及6km的局地化尺度能较好地滤除采样误差造成的虚假相关,同时可以将观测信息传递到无观测的模式格点;利用背景场加上空间平滑的高斯型随机扰动生成初始成员的方式较未经过平滑的方式有更好的分析效果;背景场扰动方法能够提高样本的离散度;只同化反射率的同化试验表明,反射率的同化效果较明显,也证明了集合卡尔曼滤波在非常规资料同化中的作用;增加径向风资料同化的效果优于只进行反射率同化的结果。     

Effects of Environmental Cadmium on Cadmium Accumulation,Oxidative Response,and Microelements Regulation in the Liver and Kidney of Hexagrammos otakii

The effects of cadmium(Cd)on metal accumulation,microelements contents,and antioxidant responses in Hexagram-mos otakii were studied.The fish were exposed to 0.2,2.5,or 10μg L?1 Cd for 12 or 24 days.Then,the concentration of Cd and mi-croelements(Ca,Fe,Zn,and Se)were determined in the liver and kidney.Moreover,the activities of antioxidant enzymes including superoxide dismutase(SOD),catalase(CAT),and glutathione-S-transferase(GST),and the content of malondialdehyde(MDA)in the liver and kidney were also measured.A continuous accumulation of Cd was observed throughout the experimental period.Cd accumulation was higher in liver than that in the kidney,while Ca and Fe contents were lower in liver than those in the kidney.Cd exposure resulted in a decrease of Ca and Fe concentrations in the kidney,while there was no effect on the liver.Zn and Se remained unaffected with exposure to Cd.Cd exposure induced severe oxidative stress in H.otakii,as indicated by significant induction of the activities of SOD,CAT,and GST,and a simultaneous increase of MDA content.These data show that antioxidant enzymes and mi-croelements contents can be used as potential biomarkers to monitor environmental health in fish.     

Production of Pacific White Shrimp Polycultured with Swimming Crab at Different Densities,and Nutrient Budget in the Enclosure System

This study was to evaluate the effect of stocking densities on the nitrogen and phosphorus budgets for a polyculture of the crab Portunus trituberculatus and the Pacific white shrimp Litopenaeus vannamei.The shrimps(initial weight,0.012 g)were cultured at a density of 45 shrimp m^-2,and juvenile crabs(initial weight,0.024 g)were cultured at five densities of 0,3,6,9,and 12 crabs m^-2.The treatments were grouped as C0S45,C3S45,C6S45,C9S45,and C12S45,respectively.Water quality parameters,growth of shrimp and crabs,and nitrogen and phosphorus budget were measured.The results indicated that the shrimp performances in polyculture treatments C3S45 and C6S45 were superior to those in the crab-free treatment(C0S45).The crab in treatments C3S45 and C6S45 exhibited a significantly higher final mean weight and carapace width/length than those in treatments C9S45 and C12S45.The final size and survival of crabs had a negative correlation with the increasing crab stocking density.The contents of total phos-phorus and total nitrogen and the comprehensive contamination index values were higher in the C9S45 and C12S45 treatments than in the other treatments.The conversion ratios of nitrogen for crab and shrimp growth in treatment C3S45 were significantly higher than those in the crab-free treatment.These findings indicate that polyculturing shrimp with crabs at suitable densities can improve productivity,profitability,nutrient utilization,and the environmental quality.From the 60-day treatments,the optimal culture densi-ties were 3-6 crabs m^-2 and 45 shrimps m^-2.     

Study on Seismic Damage to Buildings from the 2016 Hutubi MS6.2 Earthquake

Based on the field investigation of the building types and damage caused to them by the Hutubi M_S6.2 earthquake on December 8, 2016, we analyzed the damage characteristics and causes for different types of buildings. In conclusion we put forward some suggestions for the restoration and reconstruction in the earthquake affected area in future.     

A Method for Reducing Ocean Wave-Induced Magnetic Noises in Shallow-Water MT Data Using a Complex Adaptive Filter

In shallow-water areas, the marine magnetotelluric(MT) method faces a challenge in the investigation of seabed conductivity structures due to electrical and magnetic noises induced by ocean waves, which seriously contaminate MT data. Ocean waves can affect electric and magnetic fields to different extents. In general, their influence on magnetic fields is considerably greater than that on electric fields. In this paper, a complex adaptive filter is adopted to reduce wave-induced magnetic noises ...     

Evolution model and failure mechanisms of rainfall-induced cracked red clay slopes:insights from Xinshao County,China

Red clay landslides are widely distributed worldwide, resulting in severe loss of life and property. Although rainfall-induced red clay slopes have received extensive attention, the role of cracks in the evolutionary process of red clay slopes and their connection to failure mechanisms is still poorly understood. A comprehensive approach integrating field investigation, laboratory tests, and numerical simulations was conducted to study the 168 red clay landslides in Xinshao County, China. The re...