Application of L‐moments and Bayesian inference for low‐flow regionalization in Sefidroud basin,Iran

Reliable estimation of low flows at ungauged catchments is one of the major challenges in water‐resources planning and management. This study aims at providing at‐site and ungauged sites low‐flow frequency analysis using regionalization approach. A two‐stage delineating homogeneous region is proposed in this study. Clustering sites with similar low‐flow L‐moment ratios is initially conducted, and L‐moment‐based discordancy and heterogeneity measures are then used to detect unusual sites. Based on the goodness‐of‐fit test statistic, the best‐fit regional model is identified in each hydrologically homogeneous region. The relationship between mean annual 7‐day minimum flow and hydro‐geomorphic characteristics is also constructed in each homogeneous region associated with the derived regional model for estimating various low‐flow quantiles at ungauged sites. Uncertainty analysis of model parameters and low‐flow estimations is carried out using the Bayesian inference. Applied in Sefidroud basin located in northwestern Iran, two hydrologically homogeneous regions are identified, i.e. the east and west regions. The best‐fit regional model for the east and west regions are generalized logistic and Pearson type III distributions, respectively. The results show that the proposed approach provides reasonably good accuracy for at‐site as well as ungauged‐site frequency analysis. Besides, interval estimations for model parameters and low flows provide uncertainty information, and the results indicate that Bayesian confidence intervals are significantly reduced when comparing with the outcomes of conventional t‐distribution method. Copyright © 2013 John Wiley & Sons, Ltd.     

大叶藻形态及生长发育特征

对威海双岛湾大叶藻的形态及生长发育特征进行了实地观察和精细解剖研究。结果表明, 大叶藻的形态特征主要表现为: 营养枝具4～8 片叶, 互生, 具管状叶鞘, 叶片线型; 根状茎匍匐于底泥; 每节生两簇不定根; 雌雄同株异花, 佛焰苞花序, 两雄一雌单性无花被花交互排列于花序轴两侧, 花粉胶质丝状; 瘦果。其主要生长发育特征表现为: 叶和节间的基部具有分生组织, 叶和节间生长主要体现为基部的生长; 腋芽的发育具有明显的窗口期; 先出叶先于侧枝萌发; 实生苗或克隆分株的端枝经过近一年的生长分化为成生殖枝, 开化结果后即死亡; 同一花序内的雌花先于雄花开放, 水中受精, 果实败育率较高。大叶藻营养、生殖器官形态结构的特化和它们生长发育的时序优化充分体现了该种对海洋水生环境的高度适应性。     

宁夏枸杞气候区划

利用2000-2001年全国北方地区的100余份枸杞样品和土壤样品,结合当地采样期间的气象资料和宁夏各地枸杞试验资料和历史产量资料所确定的一系列影响枸杞产量和品质的农业气象指标,从1∶25万数字地图上转换出250 m×250 m格距的经纬度和数字高程资料,利用改进的小气候细网格订正推算方法,推算了宁夏气温稳定通过10 ℃期间的热量资源、光照资源分布;利用3点平滑推算了气温稳定通过10 ℃期间全区的降水量分布及关键时段平均温度场,根据枸杞的指标进行了细网格区划,从产量和品质两个方面得到了详细分区.     

An Updated Coupled Model for Land-Atmosphere Interaction. Part II： Simulations of Biological Processes

In Part I, the authors succeeded in coupling the spectral atmospheric model （SAMIL_R42L9） developed at the State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics, Chinese Academy of Sciences （LASG/IAP/CAS） with the land surface model, Atmosphere-Vegetation-Interaction-Model （AVIM） and analyzed the climate basic state and land surface physical fluxes simulated by R42_AVIM. In this Part Ⅱ, we further evaluate the simulated results of the biological processes, including leaf area index （LAI）, biomass and net primary productivity （NPP） etc. Results indicate that R42_AVIM can simulate the global distribution of LAI and has good consistency with the monthly mean LAI provided by Max Planck Institute for Meteorology. The simulated biomass corresponds reasonably to the vegetation classifications. In addition, the simulated annual mean NPP has a consistent distribution with the data provided by IGBP and MODIS, and compares well with the work in literature. This land-atmosphere coupled model will offer a new experiment tool for the research on the two-way interaction between climate and biosphere, and the global terrestrial ecosystem carbon cycle.     

Numerical model for the SNR DEM L316: simulated X-ray emission

We present a two-component supernova remnant model for the case of Magellanic remnant DEM L316 obtained from two-dimensional, axisymmetric hydrodynamic simulations. We study different scenarios which consider a possible collision between the shells and also the effects of thermal conduction. Synthetic X-ray maps were obtained from numerical results in order to directly compare with the observed morphology of this object. We find a good agreement is achieved when thermal conduction is included, reproducing both the observed morphology and the total X-ray luminosity very well. Finally, our results suggest that the two components of DEM L316 are not in physical interaction.     

单界面反射的反射波法频率域解释方法的研究

根据纵波在细杆中传播的理论，在单界面反射的条件下，本文推导了时域曲线的振幅谱，分解为振源振幅谱和｜L（ω）｜函数的过程，井推导了与｜L（ω）｜函数的极值相关的L（a）函数．利用L（ω）模函数的特性，就能较为准确的确定反射界面的反射系数和反射波往返时两个参数，为反射波法桩基质量检测的频率城解释方法提供了一定的理论根据．     

Geochemistry of early Palaeozoic amphibolites from the Orlica-Śnieżnik dome,Bohemian massif: petrogenesis and palaeotectonic aspects

Orthoamphibolites within and marginal to the Orlica-Śnieżnik dome in the eastern Bohemian massif are associated with a series of Proterozoic-Lower Palaeozoic supracrustal meta-sediments of the Stronie, Nové Město and Staré Město formations. Massive and variably foliated amphibolites range from common epidote-plagioclase-blue-green/green hornblende varieties to assemblages with diopside, garnet and brown amphibole. All the amphibolites have a basaltic composition and are divided into three main chemical groups which are intimately associated in the field: main series tholeiites, low-Ti tholeiites and alkali basalts. All groups exhibit a common enrichment in LIL elements+Nb+Ta (relative to high-field-strength elements) which reflects contamination by upper continental crust and/or pelagic sediment compositions. The gross chemistry of the tholeiitesapproaches that for MORB, although the geological environment and nature of crustal contamination suggests that the basaltic precursors were probably emplaced in a rifted ensialic basinal environment. If the amphibolites are representative of an early phase of the Lower Palaeozoic fragmentation of Gondwanaland, then rifting did not fully develop ocean crust. The wider significance of the chemical interpretation implies that some of the variation from Variscan Proterozoic-Palaeozoic metabasite suites that is ascribed to a complex of different eruptive settings could be accounted for by variable contamination and/or source composition.     

悬浮液原子荧光光谱法测定化探样品中的痕量汞

拟定了将悬浮液技术与汞蒸气原子荧光光谱法相结合测定化探样品中痕量Ｈｇ的分析方法。控制悬浮液中试样粒度在２００目，试样质量浓度１５ｇ／Ｌ，用电磁搅拌和载气搅拌保证悬浮液分散稳定，水溶液标准作校正曲线，方法的检出限为６ｎｇ／ｇＨｇ。对水系沉积物国家标准物质中痕量Ｈｇ进行测定，结果与标准值相符，对含Ｈｇ０１０μｇ／ｇ的ＧＢＷ０７３０５（ＧＳＤ５）测定１１次，ｘ为０１０５μｇ／ｇ，ＲＳＤ为５４％。     

On the nature of regional seismic phases–II. On the influence of structural barriers

The blockage of the L _g wave by crustal barriers such as continental margins and graben structures has long been recognized as providing a very useful tool for mapping large-scale lateral crustal variations along the propagation path. Numerical simulation of L _g -wave propagation in complex anelastic media using the pseudospectral method provides insight into the nature of the propagation process using both snapshots of the wavefield and synthetic seismograms. A variety of 2-D structures have been investigated, including the influence of sediments, crustal thickness and attenuation.
Thick sedimentary basins covering a graben structure can have a major influence, since they remove L _g energy by generating P conversion and scattering–the principal mechanisms for strong L _g attenuation across a graben. The reduction of the L _g energy is reinforced by anelastic attenuation in the sediments as well as the influence of the gradually thinning crustal waveguide associated with an elevated Moho.
The extinction of L _g in a sequence of explosions fired across the central graben of the North Sea can be simulated by numerical calculations for the structure derived from refraction experiments.