辽中南城市群城市竞争力综合评价与时间演变分析

以辽中南城市群为对象,选取33个评价指标,组成评价指标体系,并运用SPSS软件对城市竞争力进行定量实证分析。运用主成分分析法评价辽中南城市群城市竞争力及其时间演变,并在此基础上采用聚类分析法,对辽中南城市群的10个城市进行竞争力类型划分。结果表明:大连和沈阳城市竞争力强;鞍山、本溪和抚顺竞争力较强;营口、丹东、辽阳、盘锦和铁岭竞争力弱;辽中南城市群整体竞争力水平略有下降,城市间经济发展不平衡。     

洛阳地震台面波震级的偏差研究

利用洛阳地震台1985 ～ 2003 年记录的1755 个地震的面波资料,采用与国家地震台网中心相同的面波震级公式,研究了该台测定的面波震级与国家地震台网中心测定面波震级之间的偏差。结果表明,洛阳地震台测定面波震级的偏差与震中距之间有明显的相关性,在1°≤Δ≤130°范围内面波震级由偏小0. 1 逐渐变化到偏大,Δ≥20°时偏大0. 2 ～ 0. 3;在130° ＜ Δ≤180°范围内偏大0. 2。     

Uncertainty assessment and optimization of hydrological model with the Shuffled Complex Evolution Metropolis algorithm: an application to artificial neural network rainfall-runoff model

Assessment of parameter and predictive uncertainty of hydrologic models is an essential part in the field of hydrology. However, during the past decades, research related to hydrologic model uncertainty is mostly done with conceptual models. As is accepted that uncertainty in model predictions arises from measurement errors associated with the system input and output, from model structural errors and from problems with parameter estimation. Unfortunately, non-conceptual models, such as black-box models, also suffer from these problems. In this paper, we take the artificial neural network (ANN) rainfall-runoff model as an example, and the Shuffled Complex Evolution Metropolis algorithm (SCEM-UA) is employed to analysis the parameter and predictive uncertainty of this model. Furthermore, based on the results of uncertainty assessment, we finally arrive at a simpler incomplete-connection artificial neural network (ICANN) model as well as with better performance compared to original ANN rainfall-runoff model. These results not only indicate that SCEM-UA can be a useful tool for uncertainty analysis of ANN model, but also prove that uncertainty does exist in ANN rainfall-runoff model. Additionally, in some way, it presents that the ICANN model is with smaller uncertainty than the original ANN model.     

On the growth of disturbances to forced and dissipated barotropic flows

Abstract

We consider the growth of disturbances to large-scale zonally-asymmetric steady states in a truncated spectral model for forced and dissipated barotropic flow. A variant of the energy method is developed to optimize the instantaneous disturbance energy growth rate. The method involves solving a matrix eigenvalue problem amenable to standard numerical techniques. Two applications are discussed. (1) The global stability of a family of steady states is assessed in terms of the Ekman damping coefficient r. It is shown that monotonic global stability (i.e., every disturbances energy monotonically decays to zero) prevails when r≥r_c . (2) Initially fastest-growing disturbances are constructed in the r<r_c regime. Particular attention is paid to a subregion of the r<r_c regime where initially-growing disturbances exist despite stability with respect to normal modes. Nonlinear time-dependent simulations are performed in order to appraise the time evolution of various disturbances.     

Mass Balance Study on Phosphorus Removal in Constructed Wetland Microcosms Treating Polluted River Water

A number of studies have showed that the mass removal rates of phosphorus (P) in different constructed wetlands (CWs) varied significantly, and it is essential to quantify the contributions of major P removal processes in order to improve system design. The objective of this study was to investigate the effects of vegetation, hydraulic retention time (HRT), and water temperature on P removal from polluted river water and to quantify the contributions of different P removal pathways in surface CWs. Results showed that the average total P removal rates ranged between 2.69 and 20.84 mg/(m² day) in different seasons and were influenced significantly by vegetation, HRT, and water temperature. According to the mass balance approach, plant uptake removed 4.81–22.33% of P input, while media storage contributed 36.16–49.66%. Other P removal processes such as microbiota uptake removed around 0.26–4.13%. Media storage and plant uptake were identified as the main P removal processes in surface CWs treating polluted river water. This illustrated the importance of selecting media and plants in CWs for future practical application.     

Accuracy analysis for SST gravity field model in China

Taking China as the region for test the potential of the new satellite gravity technique, satelliteto-satellite tracking for improving the accuracy of regional gravity field model is studied. With WDM94 as reference, the gravity anomaly residuals of three models, the latest two GRACE global gravity field model (EIGEN_GRACE02S, GGM02S) and EGM96, are computed and compared. The causes for the differences among the residuals of the three models are discussed. The comparison between the residuals shows that in the selected region, EIGEN_GRACE02S or GGM02S is better than EGM96 in lower degree part (less than 110 degree). Additionally, through the analysis of the model gravity anomaly residuals, it is found that some systematic errors with periodical properties exist in the higher degree part of EIGEN and GGM models, the results can also be taken as references in the validation of the SST gravity data.     

The assessment of health impact caused by energy use in urban areas of China: an intake fraction–based analysis

The Indian Ocean Tsunami of December 2004 caused inundation of seawater along the Northern coast of Tamil Nadu, India, resulting in loss of 8,000 people with extensive damage to properties. The paper describes the inundation of seawater in two northern districts, namely Kancheepuram and Villupuram districts, which showed distinct patterns of inundation of seawater and run-up levels due to variations in geomorphic features. TUNAMI N2 model was used to predict the seawater inundation for earthquakes occurred in 1881 at Car Nicobar, Sumatra 2004 and a worst-case scenario. The coastal areas with beaches having gentle slope showed more inundation compared with coastal areas having varied slope and habited by sand dunes and coastal vegetation. Appreciable inundation of seawater with tsunami simulated for 1881 Car Nicobar indicated that proximity to the source plays a major role besides earthquake parameters in causing inundation. The worst-case scenario generated from subduction zone of Car Nicobar using Sumatra 2004 earthquake parameters revealed extreme vulnerability of coasts of both the districts to giant tsunamis.     

Risk evaluation of China’s natural disaster systems: an approach based on triangular fuzzy numbers and stochastic simulation

To deal effectively with the evaluation problem of natural disaster risk system affected by many uncertain factors, a multivariate connection number expression is presented. This expression is based on the index samples and evaluation grade criterions of natural disaster risk system and is capable of describing the hierarchy property and fuzziness of membership relationship between index samples and evaluation grade criterions. In this proposed method, the fuzzy evaluation grade criterion problem is resolved by combining triangular fuzzy numbers with multivariate connection number theory, and triangular fuzzy numbers are used to express the discrepancy degree coefficients of connection number and evaluation index weights. Accordingly, a connection number-based evaluation method for the natural disaster system of China (named CN-TFN for short) is established using triangular fuzzy numbers and stochastic simulation. The application results show that the spatial distribution of natural disaster risk grades of China has the trend of aggrandizement from west to east of China. The economically developed and densely populated coastal areas are very likely to have a high level of natural disaster risk grade or above; thus, these areas are the key regions of the natural disaster risk management of China. The results also show that the CN-TFN is able to reflect practical conditions of the evaluation problem of natural disaster system and to provide more reliability information as compared to the existing evaluation methods. This is as a result of its comprehensive usage of various information of subjective and objective uncertainties in the evaluation process of natural disaster risk system and its expression by confidence intervals. Due to the simplicity and generalization, the CN-TFM is applicable to comprehensive risk grade evaluation of various natural disaster systems.     

极化散射特性保持的改进迭代Wishart分类算法

为克服基于极化散射特性保持的迭代Wishart分类算法不适用于城区及对混合散射像素分类欠理想等不足,本文提出一种改进方法.其基本思想是先应用四分量分解算法将像素分成4种基本散射类型和混合散射类型,接着以平均合并度为指导对基本散射类型中的像素自适应聚类,最后对所有像素进行散射特性保持的迭代Wishart分类.试验结果表明...