2006年5-6月国内环境事件

简要统计了2006年5-6月国内发生的各种环境事件197起,包括沙尘天气18起,污染事件48起,地震13起,山体滑坡和泥石流22起,虫害12起,旱灾15起,以及其他自然灾害69起.对自然灾害进行了讨论.     

The Merseyside Accident Information Model (MAIM) can reveal components of accidents that lead to attendance at fracture clinics and cause disability: a new approach to accident prevention

The objectives of this study were to identify components of accidents that cause the most disability and to discover the principal sources of injuries treated in the fracture clinics. Patients attending fracture clinics of the Royal Liverpool University Hospital were interviewed using a portable computer-based questionnaire, the Merseyside Accident Information Model (MAIM). Patients were followed up by telephone interview or letter to enquire about disability continuing after discharge. Disability was measured by the pre-accident to post-discharge changes in scores for 11 normal functions. Of the 1326 patients interviewed, 900 (68%) were successfully followed up and 37% reported disability after discharge. First events ‘tripping’, ‘slipping’ and ‘other underfoot events’ accounted for 433 patients (194 reporting disability), and ‘collapsed/fainted — no other event' for 66 patients (27 reporting disability). Activities at the time of accident most frequently associated with disability involved moving about on foot. Among first event objects, ground surfaces and underfoot hazards were reported in 35%. Sources of injuries included underfoot accidents (48%), sport (13%), and transport accidents (12%.). Underfoot accidents contributed to 58% of patients reporting disability, sport 6% and transport accidents 11%. Underfoot accidents together with ‘collapsed/fainted — no other event’ accounted for 79% of female patients reporting disability and 50% of men. Such data could be used for cost-effective targeting of preventative measures, and to study the effectiveness of accident prevention initiatives.     

Using hidden Markov chains and empirical Bayes change-point estimation for transect data

Consider a lattice of locations in one dimension at which data are observed. We model the data as a random hierarchical process. The hidden process is assumed to have a (prior) distribution that is derived from a two-state Markov chain. The states correspond to the mean values (high and low) of the observed data. Conditional on the states, the observations are modelled, for example, as independent Gaussian random variables with identical variances. In this model, there are four free parameters: the Gaussian variance, the high and low mean values, and the transition probability in the Markov chain. A parametric empirical Bayes approach requires estimation of these four parameters from the marginal (unconditional) distribution of the data and we use the EM-algorithm to do this. From the posterior of the hidden process, we use simulated annealing to find the maximum a posteriori (MAP) estimate. Using a Gibbs sampler, we also obtain the maximum marginal posterior probability (MMPP) estimate of the hidden process. We use these methods to determine where change-points occur in spatial transects through grassland vegetation, a problem of considerable interest to plant ecologists.     

基于RS和GIS的赤水河流域植被覆盖度与各地形因子的相关强度研究

以赤水河流域为研究区域,综合运用遥感和GIS技术,用TM遥感影像反演植被覆盖度,用数字高程模型(DEM)提取地形因子并进行子流域的划分与构建;首先借助空间叠加分析,研究了区内植被覆盖度分别随高程、坡度及坡向变化的规律;然后从数理统计的角度分析区内不同植被覆盖度与地形等级因子的相关性,并就相关强度进行排序。研究表明:1、在赤水河流域,中度以上植被覆盖度与坡度、高程与之间,并不是单一的正比关系,其随坡度和高程的增加而先增加后减小,存在着临界坡度区间和临界高程区间。2、不同植被覆盖度下各地形因子的影响程度明显不同。对各级植被覆盖,坡度和坡向对其的影响都明显高于高程;中度植被覆盖受坡向影响较为显著,但随着植被覆盖度的增高坡度的影响越来越显著。该研究对喀斯特区域生态环境的评价和改良具有重要参考价值,同时也为喀斯特地区的植被保护和石漠化防治提供决策依据。     

国内石油行业上游污染物排放统计若干问题探讨

根据规定,石油行业上游要定期报告污染物的排放数据。与排放有关的生产活动高度分散,规模和性质差异很大,使统计工作存在一定的复杂性。文章就统计范围和统计分析方面存在的问题进行初步探讨,并提出建议。对于非常规形态的排放、可"忽略"的排放,应界定相应的规则和计算方法。适当增加统计的分类,以充分满足环境管理的需求。在报告数据前,要采用多种方法进行验证。     

Nutrient Sources and Transport in the Missouri River Basin,with Emphasis on the Effects of Irrigation and Reservoirs1

Brown, Juliane B., Lori A. Sprague, and Jean A. Dupree, 2011. Nutrient Sources and Transport in the Missouri River Basin, With Emphasis on the Effects of Irrigation and Reservoirs. Journal of the American Water Resources Association (JAWRA) 47(5):1034‐1060. DOI: 10.1111/j.1752‐1688.2011.00584.x Abstract: SPAtially Referenced Regressions On Watershed attributes (SPARROW) models were used to relate instream nutrient loads to sources and factors influencing the transport of nutrients in the Missouri River Basin. Agricultural inputs from fertilizer and manure were the largest nutrient sources throughout a large part of the basin, although atmospheric and urban inputs were important sources in some areas. Sediment mobilized from stream channels was a source of phosphorus in medium and larger streams. Irrigation on agricultural land was estimated to decrease the nitrogen load reaching the Mississippi River by as much as 17%, likely as a result of increased anoxia and denitrification in the soil zone. Approximately 16% of the nitrogen load and 33% of the phosphorus load that would have otherwise reached the Mississippi River was retained in reservoirs and lakes throughout the basin. Nearly half of the total attenuation occurred in the eight largest water bodies. Unlike the other major tributary basins, nearly the entire instream nutrient load leaving the outlet of the Platte and Kansas River subbasins reached the Mississippi River. Most of the larger reservoirs and lakes in the Platte River subbasin are upstream of the major sources, whereas in the Kansas River subbasin, most of the source inputs are in the southeast part of the subbasin where characteristics of the area and proximity to the Missouri River facilitate delivery of nutrients to the Mississippi River.     

西部地级市环境监测站转型期视野中的环境统计组织体系建设探讨

通过总结西部某地级市“十一五”环境统计组织体系建设中存在的问题，从地级市环境监测站历史性转型期视野出发，提出地级市的环境统计组织建设应该依托于环境监测站的建设与发展，全力推进环境统计工作和环境监测的协同发展。     

嘉陵江流域洪水区域分析

嘉陵江流域位于长江上游 ,是长江流域面积最大的支流 ,也是长江洪水的主要来源之一。用一种新的洪水区域分析方法———标度分析法对年最大洪峰流量区域变化的性质进行了研究。标度分析法的基本思想是认为在具有相似的地理、地质和气候条件的区域内洪水的空间变化满足标度不变性 ,将不同的地区划分成不同的区域 ,在同一子区域内用标度变换来对洪水资料进行处理 ,这种思想具有现实的普遍意义。对嘉陵江流域洪水资料研究的结果表明标度不变性在一定程度上确实存在 ,且表现出多标度性 ,也就是说不同频率 p下的标度指数θ(p)有不同的值。因此用标度分析法进行洪水区域分析是可行的。为了实际应用 ,最后还计算了嘉陵江流域不同频率p的标度指数θ(p)值 ,由这些结果可以实现由有资料地区的洪水资料对无资料地区洪水进行粗估     

ESTIMATING AQUIFER PARAMETERS FROM A HORIZONTAL WELL PUMPING TEST IN AN UNCONFINED AQUIFER1

ABSTRACT: A pumping test on a phreatic glacial till aquifer was performed near Ames, Iowa, in November 1990. The head in a horizontal well was pumped down rapidly and then held constant for the duration of the 30-hour test. Throughout the test, the flow rate at the pumped well and the head at an adjacent vertical observation well were recorded. The pumping test data were used to determine the hydraulic conductivity and specific yield of the aquifer. The results indicate a hydraulic conductivity of 2.23 × 10^?5 cm/s and a representative specific yield of 0.03. Hydraulic conductivity was calculated by a simple integration of Darcy's Law after extrapolating the data to steady state. Specific yield was determined by use of several methods from the literature and a new method proposed by the author. The results show that specific yield increases with time, and that each method is within an order of magnitude of the others.     

Large Biases in Regression‐Based Constituent Flux Estimates: Causes and Diagnostic Tools

It has been documented in the literature that, in some cases, widely used regression‐based models can produce severely biased estimates of long‐term mean river fluxes of various constituents. These models, estimated using sample values of concentration, discharge, and date, are used to compute estimated fluxes for a multiyear period at a daily time step. This study compares results of the LOADEST seven‐parameter model, LOADEST five‐parameter model, and the Weighted Regressions on Time, Discharge, and Season (WRTDS) model using subsampling of six very large datasets to better understand this bias problem. This analysis considers sample datasets for dissolved nitrate and total phosphorus. The results show that LOADEST‐7 and LOADEST‐5, although they often produce very nearly unbiased results, can produce highly biased results. This study identifies three conditions that can give rise to these severe biases: (1) lack of fit of the log of concentration vs. log discharge relationship, (2) substantial differences in the shape of this relationship across seasons, and (3) severely heteroscedastic residuals. The WRTDS model is more resistant to the bias problem than the LOADEST models but is not immune to them. Understanding the causes of the bias problem is crucial to selecting an appropriate method for flux computations. Diagnostic tools for identifying the potential for bias problems are introduced, and strategies for resolving bias problems are described.