北京极端天气事件及其与区域气候变化的联系

应用逐日观测资料分析了北京极端天气事件的变化及其与区域气候变暖的可能联系，得到了如下结论：（1）近30多年来高温和闷热事件在增加，低温、大风、雷暴和大雾事件在减少，暴雨和沙尘暴的出现频率无明显的变化。（2）高温、闷热、低温、大风、雷暴和大雾存在着较强的年际变化，但不具有明显的周期性特征，暴雨和沙尘暴事件分别存在10年和8～10年的主周期变化。（3）年平均气温和高温、闷热、低温、大风等极端事件之间存在着较强的相关性，这些极端天气事件的变化与区域气候变暖关系密切。     

ENSO: EXTREME CLIMATE EVENTS AND THEIR IMPACTS ON ASIAN DELTAS1

ABSTRACT: Proxy climate data for the last 500 years collected from the archives of counties in the Yangtze River Delta, China, were analyzed to identify the occurrence of extreme climate events, the pattern of such occurrences and their relationships to El Nino-Southern Oscillation (ENSO). This study identified the cycle periods of 3.5, 5.5 and 8.6 years for floods and 18.5 years for droughts in the Yangtze River Delta during the last 500 year period and noted 16 regional (delta wide) extreme events during this period. All regional (delta wide) extreme climate events during the last 500 years (since 1500 A.D.) occurred either during or immediately after ENSO (5–6 year) activities. Hydrological impacts of extreme climate events, such as major floods and droughts, on human systems have long been among the foremost concerns of the Pacific Rim countries. Management of systems increasingly dominated by humans, such as Asian delta regions, should, therefore, include consideration of major climate variability, ENSO events and the extent of climate changes, as well as consideration of the trends associated with human growth and institutional changes.     

2016年11-12月国内环境事件

简要统计了2016年11-12月国内发生的各种环境事件87起,包括沙尘天气4起,污染事件18起,地震50起,山体滑坡和泥石流6起,以及其他自然灾害9起.     

2017年3-4月国内环境事件

简要统计了2017年3-4月国内发生的各种环境事件117起,包括沙尘天气16起,污染事件26起,地震30起,山体滑坡和泥石流13起,以及其他自然灾害32起.     

2017年7-8月国内环境事件

简要统计了2017年7-8月国内发生的各种环境事件160起,包括沙尘天气4起,污染事件15起,地震44起,山体滑坡和泥石流26起,旱灾10起以及其他自然灾害61起.     

现代环境事件的冰芯记录

1997年9月，在喜马拉雅山中段希夏邦马峰北坡达索普冰川海拔7000m冰雪平台钻取14m冰芯一支。1990年以来冰芯中主要离子浓度的变化表明，现代环境事件在达索普冰川雪冰中有一定的记录。已有的证据表明1991年达索普冰芯中SO^2-4浓度的最高值最大可能是由海湾战争引发的1991年春季科威特油井燃烧污染物所致。冰芯中陆源离子（如Ca^2 和SO^2-4等）记录与我国西北地区春季沙尘暴具有某些相关性，其逐年变化趋势与新疆13个城市的降尘变化有一定的共性。     

A Method for Constructing a Social Vulnerability Index: An Application to Hurricane Storm Surges in a Developed Country

An important goal of vulnerability assessment is to create an index of overall vulnerability from a suite of indicators. Constructing a vulnerability index raises several problems in the aggregation of these indicators, including the decision of assigning weights to them. The purpose of this paper is to demonstrate a method of aggregating vulnerability indicators that results in a composite index of vulnerability, but that avoids the problems associated with assigning weights. The investigators apply a technique based on Pareto ranking to a complex, developed socioeconomic landscape exposed to storm surges associated with hurricanes. Indicators of social vulnerability to this hazard are developed and a principal components analysis is performed on proxies for these indicators. Overall social vulnerability is calculated by applying Pareto ranking to these principal components. The paper concludes that it is possible to construct an effective index of vulnerability without weighting the individual vulnerability indicators.     

Markovian–Octant analysis based stable turbulent shear stresses in near-bed bursting phenomena of vortex settling chamber

The coherent structure in near-bed turbulent boundary layer of vortex chamber, particularly the bursting events and their associated shear stresses play the main role in sediment flushing process and consequently the trap efficiency of the vortex settling chamber. Hence, three-dimensional velocity measurements were made at 48 points near the bed of physical model of vortex chamber by using Micro-ADV. The pattern of sediment deposition at the bed of vortex settling chamber reveals three separate regions formed by three predominant currents of inlet flow, flushing flow and outlet over flow. Additionally, due to the instability and three-dimensional nature of the bursting events near the bed of chamber, the new method of Markovian–Octant analysis was applied to study the different classes of near-bed stable shear stresses of vortex chamber in three dimensions. Moreover, the role of each class of stable shear stresses on Sediment transport mechanism at the bed of vortex chamber is investigated.     

APPLICATION OF SCS INFILTRATION MODEL1

ABSTRACT: The SCS infiltration model was applied to the Ralston Creek watershed in eastern Iowa. The criteria to determine the various model parameters were revised to obtain a better agreement between the observed and computed total runoffs. A procedure to calibrate the infiltration model is presented. The infiltration model was used in conjunction with an overland flow model to develop flood hydrographs. The results indicate that SCS infiltration model adequately describe the distribution of losses.     

PREDICTING PEAK STREAM FLOW FROM AN UNDISTURBED WATERSHED IN THE CENTRAL APPALACHIANS1

ABSTRACT: Data from a small forested catchment were used to model peak stream flow as a function of basic hydrologic variables associated with 112 rain storms. Rainfall depth and initial stream flow rate accounted for 87.1 percent of peak flow variability. Forty expressions of rainfall intensity (describing both the temporal sequence of intensity for 20 equal storm intervals, and maximum intensity for 20 separate interval lengths) were used in an attempt to improve the predictability of basic models. None of the intensity parameters improved predictability by as much as 2 percent, apparently because the most intense rainfall bursts generally occurred near the beginning of storm periods. Mean rainfall intensity for entire storms was generally as effective as any of the shorter interval intensities, and its use helped to linearize the relationship between peak flow and rainfall depth and duration.