南北地震带北段近期强震趋势研究

2008年5月12日汶川8.0级地震后,南北地震带可能进入新一轮的强震活跃期.从汶川8.0级地震以来ML≥5.0地震活动空间分布特征来看,近期南北地震带北段与中、南段存在较大差异.由南北地震带强震前孕震区中强地震活动特征,并结合当前5级地震活动情况,认为应同时关注南北地震带中、南段和北段的强震危险性.甘东南地区出现的4级地震空区被2011年2月23日迭部-岷县交界ML4.4地震打破后,2011年11月1日空区周边又发生了青川Ms5.4地震,表明该空区及周边地区的地震活动增强.类比1990年共和7.0级地震前的空区演化过程,认为甘东南地区存在发生7级地震的可能.结合对甘东南地区主要大型断裂7级地震复发周期的综合分析认为,需关注南北带北段毛毛山断裂和金强河断裂、香山-天景山断裂东段、黄河断裂灵武段、西秦岭北缘断裂、六盘山-宝鸡断裂和东昆仑断裂东段玛沁-玛曲段发生7级地震的可能.     

红山地震台震相到时准确测定

利用工具软件对选取的红山地震台波形数据进行分析处理,从波形包含的频率成分特征上可以区分地脉动、干扰、地震;利用Fourier变换、滤波、复时谱分析、高斯小波分析、莫莱小波分析、DB小波分析等手段,综合分析处理可准确标注地震震相.     

An improved statistical analogue downscaling procedure for seasonal precipitation forecast

Seasonal forecasting can be highly valuable for water resources management. Hydrological models (either lumped conceptual rainfall-runoff models or physically based distributed models) can be used to simulate streamflows and update catchment conditions (e.g. soil moisture status) using rainfall records and other catchment data. However, in order to use any hydrological model for skillful seasonal forecasting, rainfall forecast at relevant spatial and/or temporal scales is required. Together with downscaling, general circulation models are probably the only tools for making such seasonal predictions. The Predictive Ocean Atmosphere Model for Australia (POAMA) is a state-of-the-art seasonal climate forecast system developed by the Australian Bureau of Meteorology. Based on the preliminary assessment on the performance of existing statistical downscaling methods used in Australia, this paper is devoted to develop an analogue downscaling method by modifying the Euclidian distance in the selection of similar weather pattern. Such a modification consists of multivariate Box–Cox transformation and then standardization to make the resulted POAMA and observed climate pattern more similar. For the predictors used in Timbal and Fernadez (CAWCR Technical Report No. 004, 2008), we also considered whether the POAMA precipitation provides useful information in the analogue method. Using the high quality station data in the Murray Darling Basin of Australia, we found that the modified analogue method has potential to improve the seasonal precipitation forecast using POAMA outputs. Finally, we found that in the analogue method, the precipitation from POAMA should not be used in the calculation of similarity. The findings would then help to improve the seasonal forecast of streamflows in Australia.     

An inexact fuzzy-random-chance-constrained air quality management model

An inexact fuzzy-random-chance-constrained programming model (IFRCCMM) was developed for supporting regional air quality management under uncertainty. IFRCCMM was formulated through integrating interval linear programming within fuzzy-random-chance-constrained programming framework. It could deal with parameter uncertainties expressed as not only fuzzy random variables but also discrete intervals. Based on the stochastic and fuzzy chance-constrained programming algorithms, IFRCCMM was solved when constraints was satisfied under different satisfaction and violation levels of constraints, leading to interval solutions with different risk and cost implications. The proposed model was applied to a regional air quality management problem for demonstration. The obtained results indicated that the proposed model could effectively reflect uncertain components within air quality management system through employing multiple uncertainty-characterization techniques (in random, fuzzy and interval forms), and help decision makers analyze trade-offs between system economy and reliability. In fact, many types of solutions (i.e. conservative solutions with lower risks and optimistic solutions with higher risks) provided by IFRCCMM were suitable for local decision makers to make more applicable decision schemes according to their understanding and preference about the risk and economy. In addition, the modeling philosophy is general and applicable to many other environmental problems that may be complicated with multiple forms of uncertainties.     

Factors Affecting UV/H2O2 Oxidation of 17α‐Ethynyestradiol in Water

In this study, bench‐scale experiments were conducted to examine the UV/H₂O₂ oxidation of 17α‐ethynyestradiol (EE2) in water in a batch operation mode. The EE2 degradation exhibited pseudo‐first‐order kinetics, and the removal was ascribed to the production of hydroxyl radicals (^?OH) by the UV/H₂O₂ system. Typically, the EE2 oxidation rate increased with increasing UV intensity and H₂O₂ dose, and with deceasing initial EE2 levels and solution pH. At EE2₀ = 650 µg/L, UV intensity = 154 µW/cm², H₂O₂ = 5 mg/L, and neutral pH, the UV/H₂O₂ treatment was able to remove 90% of the EE2 content within 30 min. Four anions commonly present in water were found to inhibit EE2 degradation to varying degrees: > > Cl^? > . Our results demonstrate that the described UV/H₂O₂ process is an effective method to control EE2 pollution in water.     

实物期权理论视域下我国开发商闲置土地行为分析

运用实物期权理论分析我国房地产开发商闲置土地行为.土地作为一种有限资源,在推动城镇化进程发展和促进经济平稳发展中有重要作用,其能否得到有效利用关系重大.因此,将房地产开发商的土地投资决策视为一种实物看涨期权,从而解释了在市场存在不确定时房地产企业闲置土地背后的动因;并通过延迟投资期权定价模型(B-S模型)分析开发商开发土地最佳时机的决定和影响因素,借此为房地产企业做投资决策和政府调控土地市场提供参考意见.     

An improved artificial bee colony algorithm for optimal land-use allocation

Land-use allocation is of great importance for rapid urban planning and natural resource management. This article presents an improved artificial bee colony (ABC) algorithm to solve the spatial optimization problem. The new approach consists of a heuristic information-based pseudorandom initialization (HIPI) method for initial solutions and pseudorandom search strategy based on a long-chain (LC) mechanism for neighborhood searches; together, these methods substantially improve the search efficiency and quality when handling spatial data in large areas. We evaluated the approach via a series of land-use allocation experiments and compared it with particle swarm optimization (PSO) and genetic algorithm (GA) methods. The experimental results show that the new approach outperforms the current methods in both computing efficiency and optimization quality.     

Isotopic constraints on the origin of groundwater in the Ordos Basin of northern China

Despite its extreme aridity, the Ordos Basin in northern China is rich in groundwater. Many artesian wells or springs with large fluxes are utilized for drinking, irrigation and industrial production. In a search for the origin of the groundwater, a detailed investigation of the stable isotopes of oxygen and hydrogen in the local precipitation, the river water, the springs, the well water, as well as the soil water extracted from six soil profiles in the Ordos Basin, was carried out. The data show that δD, δ¹⁸O and TDS values of the river water are similar to those of groundwater, while the TDS values of the soil water are about ten times greater than those of groundwater. Furthermore, the mean isotopic compositions of the local precipitation are significantly higher than those of river water and groundwater. Based on the chloride mass balance method, the estimated recharge rates range from 5.2 to 17.2 mm/year, with a mean value of 10.5 mm/year. The results show that the main source of recharge of the groundwater in the Ordos Basin is not the local precipitation, but must come from a region where the precipitation is characterized by much lower δD and δ¹⁸O values. In addition, the groundwater in the Ordos Basin contains a component of mantle-derived ³He and crust-derived ⁴He suggesting that the groundwater may partly derive from flows through basement faults beneath the Ordos Basin.     

Semi-automatic shallow landslide detection by the integration of airborne imagery and laser scanning data

Landslide mapping is essential for effective watershed management. In Taiwan, a typhoon or earthquake event can trigger hundreds, even thousands, of shallow landslides in mountainous watersheds. Thus, improving the efficiency of landslide mapping by means of remote sensing techniques is an important issue. This study proposes a new method that uses concurrent aerial laser scanning (ALS) data and color ortho-imagery as input data: the topographic indices of slope, surface roughness, and object height model can be derived from the ALS data and the Green–Red Vegetation Index from the ortho-images. The method first uses these topographic and spectral indices in a global, semi-automatic algorithm to separate landslide from non-landslide pixels. It then offers a region growing tool and a 3D Eraser/Painter to edit detected landslides locally. These global and local operations are designed with a user interface, which is intuitive and user-friendly. Results from four test sites in a mountainous watershed prove that the method is easy, accurate, and suitable for landslide mapping in Taiwan.