生态环境与洪旱灾害

作者将自然运动与人类活动、生态环境与气候结合起来研究，求索洪旱灾害之谜，着重探讨了其中多种生态环境因素。由大灾后的反思，找出灾害加剧的人为原因是：人中激增、生态危机、水利失修等，提出必须加强防灾减灾的对策研究。     

两种定性天气预报模型的对比分析

以南京１９６５～１９９４ 年４ 月平均气温作为预报量, 选取前期５００ ｈ Ｐａ 月平均高度场相关因子, 分别建立了事件概率回归预报模型和神经网络预报模型。通过对比分析发现, 在同等条件下,由于神经网络方法能更好地反映预报量与预报因子间的非线性关系, 并能有效避免采用事件概率回归方法预报建模时, 对预报因子分级造成信息损失的缺点。因此, 其拟合和预报效果明显优于传统的概率回归预报方法     

北京沙尘天气与源地气象条件的关系

本介绍了影响北京地区沙尘天气的沙尘源地,沙尘暴发生的条件和传输路径,分析了沙尘暴源地的气候要素特征及其对北京地区沙尘天气的影响,说明了北京沙尘天气发生和加剧的原因,影响北京地区沙尘天气的境外源地主要位于哈萨克斯坦,俄罗斯以及蒙古国境内,境内源地主要位于内蒙古和新疆,以及甘肃和青海的部分地区,沙尘天气发生必须具备三个条件：沙源,大风,气流辐合（垂直对流）,有沙源不一定起沙,但无沙源一定不起沙,沙尘暴源地的气候特征主要表现为冬季寒冷,夏季炎热,全年降水稀水,影响北京的沙尘传输路径,最主要的有两条,即西路传输和北路传输,北京沙尘天气与沙尘暴源地的春季降水比较结果表明,北京地区沙尘暴和浮尘天气发生次数与沙尘源区春季大气降水量有比较显的负相关关系,北京扬沙天气的发生与沙源区冬春季降水量相关关系不显,说明北京扬沙天气起因与源区降水没有明显的关系,北京扬沙天气主要受本地的自然条件和人为活动的影响。     

胶带输送机运输事故树可靠性的计算机模拟

以胶带输送机运输事故树的计算机模拟过程为例 ,介绍了对事故树可靠性进行计算机模拟的原理、算法以及程序运行步骤 ,编制了模拟程序。用笔者提出的理论、方法及模拟程序 ,对平顶山煤业集团一矿胶带输送机运输事故进行了事故树分析与求解 ,同时将模拟程序运行结果与最小割集法求得的理论值进行了对比 ,计算结果误差小 ,所得结论准确可靠 ,为类似事故的模拟分析提供了一种新的方法和途径     

大兴安岭林区地下火形成火环境研究

地下火作为森林中一种难以控制的燃烧现象,其形成机理极为复杂。我国大兴安岭林区是森林地下火的多发地区。对该地区2002年发生的地下火研究表明：丰富的近土壤层和地下可燃物是森林地下火发生的物质条件,气象条件促进了森林地下火的发生,特别是在遇到降水少、长期干旱、地面温度增加、相对湿度降低和可燃物干燥的情况下,就很容易引起地下火灾。地下火有地理和时间分布特征。地表火主要发生在原始森林区域,如针叶林、阔叶林或针阔混交林,都有可能发生地下火。地下火一般燃烧速度慢,持续时间长,燃烧充分,具有隐蔽性强、燃烧不连续、方向易变等特点,地下火在所有火灾中对森林危害最大,特别是对落叶松、樟子松、云杉等的破坏更为严重。     

呼和浩特强对流天气的数值模拟分析

利用三维积云数值模式模拟了呼和浩特地区强对流天气的发展过程，并结合实时雷达回波资料进行了对比分析，指出模式输出的部分物理量与理论值、雷达回波或地面天气及降雹（水）实况符合得较好。从对模式输出的几个物理量的统计分析，得出利用三维积云数值模式预测强冰雹过程的概念模型。结果表明，三维积云数值模式能用于模拟对流云特别是强对流云的发展过程，可在人工影响天气业务工作中应用并不断发展。     

可靠性分配理论在系统安全目标实现中的应用

在系统安全理论中,确定各基本事件的可靠度以实现所给定的系统安全目标值问题一直没有得到很好解决。笔者将可靠性分配理论与故障树分析方法相结合,提出了2个层次可靠度分配法:最小割集之间采取可靠度再分配法,对构成最小割集的各个基本事件之间采取等分配法。从而建立系统中各单元可靠度再分配量化模型。为便于应用,通过实例,详述系统各单元可靠性分配的计算过程。研究表明,运用该模型可准确、简便地计算出各单元的可靠度,使系统在给定的目标值条件下达到系统的安全性优化。     

REDUCING THE COST OF CONTINUOUS HYDROLOGIC-HYDRAULIC SIMULATION1

ABSTRACT: The use of continuous hydrologic-hydraulic-water quality models is inhibited by their large computer run costs relative to cost incurred with discrete event models. The fixed recurrence interval transfer (FRIT) technique is a means of achieving substantial reductions in computer costs associated with continuous models while retaining their technical advantages. The FRIT technique is applicable where it is reasonable to assume that the recurrence interval of the response of a watershed to a causative meteorologic event is the same for both “before” and “after” conditions. Example applications of the FRIT technique to the hydrologic-hydraulic modeling of floodwater storage, land use changes, and channel modifications are presented to demonstrate the procedure, to suggest the expected accuracy, and to illustrate how computer run costs might be reduced by 99% or more. The FRIT technique is intended for preliminary assessment of the impact of alternative land use conditions and structural water control measures.     

SPATIAL VARIATION OF PRECIPITATION ON THE TEXAS HIGH PLAINS1

ABSTRACT: Space autocorrelation techniques have been used to reveal the nature and spatial distribution of precipitation in the Texas High Plains. Correlation in precipitation amounts varies with both distance and direction, dropping off rapidly with distance, particularly during the warm season. The analyses can be used to estimate storm characteristics in conjunction with a wide variety of problems dealing with irrigation, crop yields, drainage and water supply, and evaluation of artificial weather modification efforts.     

EFFECTS OF THE URBAN ENVIRONMENT ON HEAVY RAINFALL DISTRIBUTION1

ABSTRACT: A network of 225 recording raingages was operated over an area of 5200 km² in the St. Louis region during 1971-1975, in conjunction with an extensive investigation of urban effects on precipitation. Study of urban-induced effects on the frequency of heavy rainstorms has revealed a pronounced increase in the occurrence of storms producing 25 mm (1 inch) or more of rain. The increase is greatest in an area that is frequently in the path of storms passing across two urban-industrial regions. Analyses of raincells (rain intensity centers) within heavy convective storms shows a pronounced increase in water yield from cells exposed to potential urban effects, compared with those exposed only to the surrounding rural environment. Naturally-occurring heavy cells tend to undergo the greatest enhancement from urban exposure. Other analyses indicate an above-average frequency of excessive rain rates for periods of five minutes to two hours downwind of the urban-industrial complex. It is concluded that urban-induced intensification of short-duration rainstorms is sufficient to merit inclusion in the design and operation of urban-area hydrologic systems that control the flow of surplus storm water.