THE SENSITWITY OF NORTHERN SIERRA NEVADA STREAMFLOW TO CLIMATE CHANGE1

ABSTRACT: The sensitivity of streamflow to climate change was investigated in the American, Carson, and Truckee River Basins, California and Nevada. Nine gaging stations were used to represent streamflow in the basins. Annual models were developed by regressing 1961–1991 streamflow data on temperature and precipitation. Climate-change scenarios were used as inputs to the models to determine streamflow sensitivities. Climate-change scenarios were generated from historical time series by modifying mean temperatures by a range of +4°C to—4°C and total precipitation by a range of +25 percent to -25 percent. Results show that streamflow on the warmer, lower west side of the Sierra Nevada generally is more sensitive to temperature and precipitation changes than is streamflow on the colder, higher east side. A 2°C rise in temperature and a 25-percent decrease in precipitation results in stream-flow decreases of 56 percent on the American River and 25 percent on the Carson River. A 2°C decline in temperature and a 25-percent increase in precipitation results in streamflow increases of 102 percent on the American River and 22 percent on the Carson River.     

VELOCITY EQUATION FOR WATER QUALITY MODELING IN GEORGIA1

ABSTRACT: Tabletop water quality modeling still plays an important role in the water pollution control activities of the Georgia Environmental Protection Division. Tabletop models are those developed with out the aid of extensive field data. One important component of GEORGIA DOSAG, our basic water quality model, is the equation used to predict flow through velocity. However, Georgia is characterized by wide physiographic diversity which reduces the effectiveness of uncalibrated velocity equations. Using 15 years of accumulated time-of-travel studies, a series of empirical velocity equations were developed and calibrated to various physiographic conditions in Georgia. Equations are available for each major soil province and for three stream flow ranges within each province - Q<100 cfs, 100<Q<1000 cfs, and Q>1000 cfs. Now, in the absence of extensive field data, we have data based velocity equations which can be tailored to each site under study.     

2002年7-10月国内安全事故数据

统计了2002年7-10月国内发生的各种安全事故1231起,包括矿业事故、交通事故、爆炸事故、火灾、毒物泄露和中毒及其他事故.统计表明,在这些事故中,矿业事故最多,占63.1%,平均每天6.5起事故,其次是交通事故(18.6%)、其他事故(6.0%)、爆炸事故(4.8%)、毒物泄露和中毒(4.1%)、火灾(3.3%).1231起事故共死亡2 773人,伤3 206人,死亡人数的百分比分别为矿业事故48.9%、交通事故34.5%、其他事故8.3%、爆炸事故3.8%、泄露中毒2.8%、火灾1.7%;受伤人数的百分比分别为交通事故51.7%、泄露中毒19.1%、矿业事故12.2%、其他事故8.1%、爆炸事故7.0%、火灾1.9%.     

PRECIPITATION CHANGES FROM 1956 TO 1996 ON THE WALNUT GULCH EXPERIMENTAL WATERSHED1

ABSTRACT: The climate of Southern Arizona is dominated by summer precipitation, which accounts for over 60 percent of the annual total. Summer and non‐summer precipitation data from the USDA‐ARS Walnut Gulch Experimental Watershed are analyzed to identify trends in precipitation characteristics from 1956 to 1996. During this period, annual precipitation increased. The annual precipitation increase can be attributed to an increase in precipitation during non‐summer months, and is paralleled by an increase in the proportion of annual precipitation contributed during non‐summer months. This finding is consistent with previously reported increases in non‐summer precipitation in the southwestern United States. Detailed event data were analyzed to provide insight into the characteristics of precipitation events during this time period. Precipitation event data were characterized based on the number of events, event precipitation amount, 30‐minute event intensity, and event duration. The trend in non‐summer precipitation appears to be a result of increased event frequency since the number of events increased during nonsummer months, although the average amount per event, average event intensity, and average event duration did not. During the summer “monsoon” season, the frequency of recorded precipitation events increased but the average precipitation amount per event decreased. Knowledge of precipitation trends and the characteristics of events that make up a precipitation time series is a critical first step in understanding and managing water resources in semiarid ecosystems.     

COUPLING OF NONPARAMETRIC FREQUENCY AND L-MOMENT ANALYSES FOR MIXED DISTRIBUTION IDENTIFICATION 1

ABSTRACT: Both L-moment and nonparametric frequency analyses were performed on a series of annual maximum floods from New Brunswick, Canada. The L-moment analysis concluded that the data were generated from a unimodal Generalized Extreme Value (GEV) distribution. However, the nonparametric frequency analysis indicated that a majority of stations followed nonunimodal mixed distributions since peak flows occur during different seasons and are the result of different generating mechanisms. The coupling of L-moment and nonparametric analyses facilitates mixed distribution identification. Thus, the nonparametric method helps in identifying underlying probability distribution, especially when samples arise from mixed distributions.     

A COMPARISON OF STATISTICAL TESTS ON THE EXTREME-VALUE TYPE-1 DISTRIBUTION1

ABSTRACT: The effects of the selections of plotting position formulae and class division schemes on goodness of fit tests are investigated for the extreme-value type-1 distribution using annual flood and annual maximum daily rainfall data. It was found that the plotting position formulae have a minor influence on the tests which involve their use, while the class division schemes may have a pronounced effect on the X²-test. The study also recommended the maximum likelihood method for fitting purposes and a new test which is independent of the afore-mentioned selections for judging the goodness of fit.     

2015年9-10月国内生产安全事故统计分析

统计了2015年9-10月国内发生的各种生产安全事故114起,其中包括交通事故、矿业事故、爆炸事故、火灾、毒物泄漏与中毒和其他事故.统计表明,在114起事故中,交通事故占64.91％,矿业事故占3.51％,爆炸事故占5.26％,火灾占2.63％,毒物泄漏与中毒占5.26％,其他事故占18.42％.114起事故共死亡520人.死亡人数的百分比分别为交通事故62.88％,矿业事故5.00％,爆炸事故5.00％,火灾4.62％,毒物泄漏与中毒3.85％,其他事故18.65％.2015年9-10月生产安全事故发生较多的5个省分别为广东(12起)、甘肃(9起)、安徽(9起)、云南(8起)和辽宁(7起);死亡人数较多的5个省分别为安徽(52人)、广东(47人)、河南(39人)、甘肃(38人)和山东(35人).     

对应分析在CFIT事故致因研究中的应用

为揭示可控飞行撞地(CFIT)事故致因规律,根据Reason-SHEL模型得出的10个CFIT事故致因因子,分析从飞行安全基金会数据库中整理出的2006—2011年间40起CFIT事故。在此基础上建立CFIT事故年份-成因列联表,再利用SPSS软件对表格进行对应分析。将事故成因和年份同时反映在二维散点图中,实现数据可视化。最后对图形进行向量、圆心接近点以及区域化等3项分析。根据结果得出,CFIT事故的主成因是人因操作和外界环境;随着年份增加,飞行员状态(药物/疲劳、经验不足)对造成CFIT事故的重要性越来越明显;不同年份有不同的重要致因因子。     

锅炉过热器爆漏原因的统计分析和预防措施

以100余起公开报道的锅炉过热器爆漏事故案例进行统计分析为基础,将引起过热器爆漏的直接原因归纳为长期超温、短期超温、腐蚀、磨损和焊接缺陷,对产生事故的机理和主要原因进行了探讨和归类,认为运行管理不当是造成过热器爆漏的最重要方面。分析并提出了设计、安装、制造、检修和运行管理过程中对爆漏风险贡献最大的各单因素及其成因。针对造成爆漏的根本原因提出了预防措施,为锅炉的安全运行和合理检修提供了科学依据。     

COMPARATIVE EVALUATION OF STATISTICAL METHODS FOR WATER SUPPLY FORECASTING1

ABSTRACT: While the correlation coefficient and standard error of estimate are frequently used when comparing models of seasonal water yield, the following criteria may be more important in selecting one model from among several alternatives: rationality of the regression coefficients, the distribution of the residual errors, and the correctness of indicators of the relative importance of the predictor variables. These criteria were used to compare seasonal water yield models that were calibrated using multiple regression, stepwise regression, principal components regression, polynomial regression using a principal components rotation, and constrained pattern search. Hydrologic data from the Upper Sevier River basin in southern Utah were used to illustrate the comparative analysis process. The prediction equations used the April-July streamflow volume as the criterion variable.