Infrared speckle imaging: Data reduction with application to binary stars

The extended Knox-Thompson reduction scheme currently in use at Kitt Peak National Observatory and Steward Observatory for the reduction of infrared speckle interferometry is described in detail. Applications of this algorithm and the less computationally intensive shift-and-add analysis to both simulated and real binary star data is presented demonstrating that the latter may be successfully used for image reconstruction by using a separately measured point source. The performance of both techniques is shown to improve by application of an iterative deconvolution algorithm to apply a priori image constraints without degradation of photometric information.Operated by the Association of Universities for Research in Astronomy Inc. (AURA) under cooperative agreement with the National Science Foundation     

用于2.4m望远镜的网络气象站

在进行天文观测时,天气因素的影响是很大的,为适应天文观测技术发展的要求,在2.4m镜附近需要建立一个网络气象站,一方面可以对天气状况实时监测,另一方面其他设备可以从网上查询并使用这些数据,以满足2.4m望远镜必须要有气象状况输入才能正常地在RoboticMode下工作的要求。文中介绍了1 wirenet气象站的原理以及软硬件设计。     

1981－2020年沂沭河流域极端降水事件特征及环流背景

利用1981—2020年沂沭河流域内12个气象台站逐日降水观测资料,西太平洋副热带高压（西太副高）指数、太平洋年代际振荡指数（PDO）等资料以及NCEP/NCAR逐日再分析资料,采用线性趋势分析、累积距平法联合滑动t检验、morlet小波分析、相关性分析、合成分析等方法,研究近40 a沂沭河流域极端降水事件的时空变化特征,并进一步研究极端降水指数与气候因子之间的相关性以及极端降水事件的异常环流背景。结果表明：沂沭河流域极端降水事件具有整体上增多且强度增强的特征,且近年来在频次和年极端降水量上波动峰间值增大,分别为6.2 d/a、538.2 mm/a,极端降水事件日趋严重。空间分布上南多北少,中部、北部较南部增速更明显。极端降水频次和年极端降水量均在1989年和2002年左右突增;极端降水强度在1989年突增,2000年左右突减。极端降水的频次、强度和年极端降水量分别以22 a、10 a和22 a的周期波动为主。西太副高的脊线位置跟频次和年极端降水量具有正相关性,PDO与频次和年极端降水量具有负相关性。东亚夏季风强度和西太副高的位置是影响沂沭河流域极端降水事件多寡的重要因子,在预测该流域的极端降水情况时可做参考依据。     

基于空间检验技术的甘肃河东地区短时暴雨预报产品误差分析

以6个短时暴雨过程为例,采用空间检验技术对甘肃河东地区短时暴雨预报产品误差进行分析。结果表明：降水概率预报对于系统性降水过程预报准确度明显高于突发性降水过程;短时暴雨预报方法的预报位置较实况偏东偏南,纬度偏差-2.1°～1.3°,经度偏差-0.4°～3.1°;强度较实况偏弱,61%本地预报方法雨强为实况的0%～90%;降水范围较实况偏小,偏小程度最多仅6个格点;强度误差占比最大,其次为范围误差,位移误差最小。预报员可基于本地短时暴雨预报方法对预报误差进行相应的调整。     

烃源岩评价分析项目的优化组合

在我国石油天然气行业中,对烃源岩评价的实验分析技术已形成一套比较成熟的方法,其中大部分已制订成国家标准或行业标准。但是在实际过程中,或者是全面测试,以致浪费大、收益小,或者是为过度节约而少测样品,造成信息严重丢失。为了分析测试能既节约成本又成果优秀,对各分析项目依据其有效性和局限性,分为基本项目、选择项目和补充项目三大类。针对不同的研究目的,分别提出了烃源岩样品快速筛选分析、烃源岩系统评价分析、下古生界海相烃源岩研究分析等相关实验测试分析项目的优化组合设计方案。     

Geochemistry of rare earth elements in a marine influenced coal and its organic solvent extracts from the Antaibao mining district, Shanxi, China

Twenty-six samples including roof, bottom and coal plies of a marine influenced coal bed were collected from the Antaibao mining district, Shanxi, China. The rare earth elements (REEs) were determined in solids and organic solvent extracts. The distribution pattern showed three distinct patterns: shale-like, LREE-rich and HREE-rich. This is attributed to the variable microenvironment of peat-forming swamp, the degree of marine influences and different REE sources. REEs in the coal are mainly controlled by detrital minerals but also affected by seawater. The chondrite-normalized REE patterns of the organic solvent extracts are distinctly different from those of corresponding original coal samples, which show a negative Eu anomaly, a depletion of middle REEs and an enrichment of HREEs. The LREEs in coal extracts are likely adsorbed by hydrogen-containing functional groups, and HREEs are likely bonded to carbon atoms.     

Flood risk perceptions and spatial multi-criteria analysis: an exploratory research for hazard mitigation

The conventional method of risk analysis (with risk as a product of probability and consequences) does not allow for a pluralistic approach that includes the various risk perceptions of stakeholders or lay people within a given social system. This article introduces a methodology that combines the virtues of three different methods: the quantifiable conventional approach to risk; the taxonomic analysis of perceived risk; and the analytical framework of a spatial multi-criteria analysis. This combination of methods is applied to the case study ‘Ebro Delta’ in Spain as part of the European sixth framework project ‘Floodsite’. First, a typology for flood hazards is developed based on individual and/or stakeholders’ judgements. Awareness, worry and preparedness are the three characteristics that typify a community to reflect various levels of ignorance, perceived security, perceived control or desired risk reduction. Applying ‘worry’ as the central characteristic, a trade-off is hypothesized between Worry and the benefits groups in society receive from a risky situation. Second, this trade-off is applied in Spatial Multi-Criteria Analysis (SMCA). MCA is the vehicle that often accompanies participatory processes, where governmental bodies have to decide on issues in which local stakeholders have a say. By using risk perception-scores as weights in a standard MCA procedure a new decision framework for risk assessment is developed. Finally, the case of sea-level rise in the Ebro Delta in Spain serves as an illustration of the applied methodology. Risk perception information has been collected with help of an on-site survey. Risk perception enters the multi-criteria analysis as complementary weights for the criteria risk and benefit. The results of the survey are applied to a set of scenarios representing both sea-level rise and land subsidence for a time span of 50 years. Land use alternatives have been presented to stakeholders in order to provide the regional decision maker with societal preferences for handling risk. Even with limited resources a characteristic ‘risk profile’ could be drawn that enables the decision maker to develop a suitable land use policy.     

Stratigraphy of nutrients and metals in sediment profiles of two dimictic lakes in North-Eastern Germany

A sedimentological study of two dimitic lakes in North-Eastern Germany provided a record of anthropogenic impacts and historical changes of water quality. The upper 50 cm sediment profiles were compared for major nutrients and selected major trace elements. The sediments were dated by ²¹⁰Pb and ¹³⁷Cs measurement. The upper 50 cm sediment profiles represent approximately the last 100 years of history in both lakes. Element analyses show different characteristic stratigraphic patterns in both lakes. Based on the nutrient and metal stratification, three characteristic time periods can be documented for both lakes. In addition to agricultural use of the catchment area, atmospheric pollution greatly influenced the metal concentration in the sediment layers. Variation in the external loading and redox conditions in the hypolimnion explain the variation in the composition and accumulation of metals in the sediment stratigraphy. No increases or changes in the trophic level of either lake could be documented based on the accumulation of the nutrients C, N and P. The ratio of Fe/Mn and Fe/Ca characterized the changing redox conditions. The stratigraphy of Pb and Zn agrees with the historical variation in atmospheric pollution and confirms literature values for Central and North Europe. The drop in Pb and Zn over the last 10–15 years is a regional effect in North-Eastern Germany.     

The Effect of Spatial Correlation of Cone Tip Resistance on the Bearing Capacity of Shallow Foundations

The effect of directional behaviour of correlation structure of cone tip resistance on the bearing capacity of shallow strip footing resting on cohesionless soil deposit in 2-D random field is analysed using probabilistic approach. The results obtained from the analysis show that the assumption of perfect (or infinite) correlation of cone tip resistance data leads to lower values of probability of failure. In contrast, the isotropic assumption of correlation behaviour based on vertical scale of fluctuation leads to higher values of probability of failure. The results also show that the transformation model would play a major role in the evaluation of variability of design property. In conclusion, the need for a proper evaluation methodology for calculation of correlation lengths of soil properties and their influence in foundation design is highlighted.     

Complexity theory, spatial simulation models, and land use dynamics in the Northern Ecuadorian Amazon

Our research questions and analytical approaches are used to examine coupled human-natural systems in the Northern Ecuadorian Amazon. They are based on complexity theory and extend from our earlier work in Cellular Automata (CA) in which land use/land cover (LULC) change patterns were spatially simulated to examine deforestation and agricultural extensification on household farms. The basic intent is to understand linkages between people and the environment by explicitly considering pattern-process relationships and the nature of feedback mechanisms among social, biophysical, and geographical factors that influence LULC dynamics within the study area. In this research, we describe how our CA modeling approach emphasizes the human dimensions of LULC change by including socio-economic and demographic characteristics at the household-level along with biophysical data that describe the resource endowments of farms, geographic accessibility of farms to roads and communities, and the evolving nature of human-environment interactions over time and space in response to exogenous and endogenous factors.A LULC change scenario is examined by comparing model outcomes generated for a base CA model and an alternative CA model to explore the effects of increases in household income on land use change patterns at the farm level, achieved as a consequence of improved geographic accessibility to roads and communities and increased off-farm employment as a household livelihood strategy. Growth or transitions rules in our CA model, as well as neighborhood associations are sensitive to socio-economic and demographic factors of households, resource endowments of farms, geographic accessibility, and the uncertainty associated with peasant farming in a frontier setting. Model outcomes indicate that increases in household income are associated with more land in pasture and more land being cultivated for crops as a result of greater access to agricultural markets. In addition, more land in secondary forest succession occurs as a consequence of greater access to roads and communities, thereby, affording a better opportunity for off-farm employment and greater levels of household income.