济南市长清区五峰山—张夏一带土壤元素与植物元素相关性分析

在济南市长清区五峰山-张夏一带选取植物样及相应的土壤样进行化验,采用线性回归的分析方法,计算出相关系数,判断其相关性,对此工作区农作物的适宜种植性具有指导作用。     

地勘单位用人问题管窥

针对某些地勘单位干部选拔及用人过程中存在的任人唯亲等不正之风问题,从“考察失真、关系利益、任用随意、责任层次不清”四个方面进行了根源剖析,并着重在“强化责任意识、严格考察程序、规范领导行为、完善监督机制”等方面提出了整改措施。     

超宽频带观测应用研讨会在北京召开

2007年9月26日,中国地震局监测预报司在北京主持召开了“超宽频带观测应用研讨会”。出席研讨会的监测预报司领导有监测预报司司长李克,处长余书明,余书明处长主持会议。中国工程院院士许绍燮到会演讲。会议承办方中国地震局地震研究所所长姚运生到会致词,龚平副所长到会。出席     

The impact of boundary on the fractional advection–dispersion equation for solute transport in soil: Defining the fractional dispersive flux with the Caputo derivatives

The inherent heterogeneity of geological media often results in anomalous dispersion for solute transport through them, and how to model it has been an interest over the past few decades. One promising approach that has been increasingly used to simulate the anomalous transport in surface and subsurface water is the fractional advection–dispersion equation (FADE), derived as a special case of the more general continuous time random walk or the stochastic continuum model. In FADE, the dispersion is not local and the solutes have appreciable probability to move long distances, and thus reach the boundary faster than predicted by the classical advection–dispersion equation (ADE). How to deal with different boundaries associated with FADE and their consequent impact is an issue that has not been thoroughly explored. In this paper we address this by taking one-dimensional solute movement in soil columns as an example. We show that the commonly used FADE with its fractional derivatives defined by the Riemann–Liouville definition is problematic and could result in unphysical results for solute transport in bounded domains; a modified method with the fractional dispersive flux defined by the Caputo derivatives is presented to overcome this problem. A finite volume approach is given to numerically solve the modified FADE and its associated boundaries. With the numerical model, we analyse the inlet-boundary treatment in displacement experiments in soil columns, and find that, as in ADE, treating the inlet as a prescribed concentration boundary gives rise to mass-balance errors and such errors could be more significant in FADE because of its non-local dispersion. We also discuss a less-documented but important issue in hydrology: how to treat the upstream boundary in analysing the lateral movement of tracer in an aquifer when the tracer is injected as a pulse. It is shown that the use of an infinite domain, as commonly assumed in literature, leads to unphysical backward dispersion, which has a significant impact on data interpretation. To avoid this, the upstream boundary should be flux-prescribed and located at the upstream edge of the injecting point. We apply the model to simulate the movement of Cl⁻ in a tracer experiment conducted in a saturated hillslope, and analyse in details the significance of upstream-boundary treatments in parameter estimation.     

Signatures of tectonic‐climatic interaction during the Late Cenozoic orogenesis along the northern Chinese Tian Shan

The Chinese Tian Shan is one of the most actively growing orogenic ranges in Central Asia. The Late Miocene‐Quaternary landscape evolution of northern Tian Shan has been significantly driven by the interaction between tectonic deformations and climate change, further modulated by the erosion of the upstream bedrocks and deposition into the downstream basins. In this study, only the accessible Kuitun River drainage basin in northern Tian Shan was considered, and detrital zircon geochronology and heavy minerals were analyzed to investigate the signature of the driving forces for Miocene sedimentation in northern Tian Shan. This study first confirmed a previously recognized tectonic uplift at ca. 7.0 Ma and further revealed that the basin sediments were mainly derived from the present glacier‐covered ridge‐crest regions during 3.3–2.5 Ma. It is suggested Late‐Pliocene to Early Pleistocene sedimentation was likely a response to the onset of the northern hemispheric glaciation. Although complicated, this study highlights that the tectonic‐climatic interaction during the Late Cenozoic orogenesis can be discriminated in the northern Chinese Tian Shan.     

基于OpenLayers的旅游地图方案研究

本文简要介绍国内最新旅游新闻动态,提出一种基于OpenLayers的多源数据整合方案,进行在线旅游地图服务,此方法定制方便灵活、开发简单,很适合中小型应用。     

Latitudinal patterns and influencing factors of soil humic carbon fractions from tropical to temperate forests

Soil humic carbon is an important component of soil organic carbon (SOC) in terrestrial ecosystems. However, no study to date has investigated its geographical patterns and the main factors that influence it at a large scale, despite the fact that it is critical for exploring the influence of climate change on soil C storage and turnover. We measured levels of SOC, humic acid carbon (HAC), fulvic acid carbon (FAC), humin carbon (HUC), and extractable humus carbon (HEC) in the 0–10 cm soil layer in nine typical forests along the 3800-km North-South Transect of Eastern China (NSTEC) to elucidate the latitudinal patterns of soil humic carbon fractions and their main influencing factors. SOC, HAC, FAC, HUC, and HEC increased with increasing latitude (all P<0.001), and exhibited a general trend of tropical < subtropical < temperate. The ratios of humic C fractions to SOC were 9.48%–12.27% (HAC), 20.68%–29.31% (FAC), and 59.37%–61.38% (HUC). Climate, soil texture, and soil microbes jointly explained more than 90% of the latitudinal variation in SOC, HAC, FAC, HEC, and HUC, and interactive effects were important. These findings elucidate latitudinal patterns of soil humic C fractions in forests at a large scale, and may improve models of soil C turnover and storage.     

南海东北部春季海表pCO_2分布及海-气CO_2通量

2013年南海东北部春季共享航次采用走航观测方式,现场测定了表层海水和大气的二氧化碳分压(pCO2)及相应参数。结合水文、化学等同步观测要素资料,对该海域pCO2的分布变化进行了探讨。结果表明,陆架区受珠江冲淡水、沿岸上升流及生物活动的影响,呈现CO2的强汇特征;吕宋海峡附近及吕宋岛西北附近海域受海表高温、黑潮分支"西伸"、吕宋岛西北海域上升流等因素影响,呈现强源特征。根据Wanninkhof的通量模式,春季整个南海东北部海域共向大气释放约4.25×104 t碳。     

阿巴嘎旗近30a春夏季干旱及影响因子分析

通过对阿巴嘎旗地区1981—2010年春季降水量、汛期降水量、≥35℃高温日数、夏季气温、春季大风和扬沙日数的资料进行分析,发现干旱不仅影响牧草生长、畜牧业产品发展,而且加剧草场退化和沙漠化。近30a来,春季风大,夏季气温高,年蒸发量与年降水量比率偏大,土壤水分严重亏缺,是造成干旱的主要原因。为了加强灾害防御、更好地趋利避害,应做好防灾减灾气象服务,及时开展人工增雨作业,采取有效的公共防御对策。     

IDNN的GPS动态测量多周跳探测与修复模型

针对GPS动态测量中预报值误差较大时多周跳探测与修复不理想的问题,在Kalman滤波动力学模型的基础上,引入嵌入时延神经网络IDNN(Input-Delay Neural Network)模型,并提出了一种基于IDNN的GPS动态测量多周跳探测与修复模型。该模型在理论上具有一定的前沿性;与Kalman滤波状态估值同步操作,便于多周跳的实时处理;而且利用尽可能多的过去无周跳预报残差向量集作为网络训练数据,兼顾GPS动态测量的动力学模型能够获取精度较高的周跳估值。实例计算表明了该方法的可靠性和可用性。