GENERATING STREAMFLOW SEQUENCES WITH TREND AND CYCLICAL MOVEMENTS1

ABSTRACT: A first-order autoregressive model had been modified with the trend and cyclical movements to generate the streamflow sequences. Three main portions were involved in this modified model, i.e., six-year cycle with trend changing; six-year cycle without trend changing; and both annual and six-year cycles with trend changing. The synthetic sequences of monthly streamflow sequences were compared with the historical records obtained from the Kissimmee River basin by using the Chi-Square test for goodness-of-fit. The results indicated that the newly proposed model has a better solution than the original model because the trend and cyclical movements involved in generating sequences are much closer to the historical records.     

RASTER-BASED HYDROLOGIC MODELING OF SPATIALLY-VARIED SURFACE RUNOFF1

ABSTRACT: The proliferation of watershed databases in raster Geographic Information System (GIS) format and the availability of radar-estimated rainfall data foster rapid developments in raster-based surface runoff simulations. The two-dimensional physically-based rainfall-runoff model CASC2D simulates spatially-varied surface runoff while fully utilizing raster GIS and radar-rainfall data. The model uses the Green and Ampt infiltration method, and the diffusive wave formulation for overland and channel flow routing enables overbank flow storage and routing. CASC2D offers unique color capabilities to display the spatio-temporal variability of rainfall, cumulative infiltrated depth, and surface water depth as thunderstorms unfold. The model has been calibrated and independently verified to provide accurate simulations of catchment response to moving rainstorms on watersheds with spatially-varied infiltration. The model can accurately simulate surface runoff from flashfloods caused by intense thunderstorms moving across partial areas of a watershed.     

新疆“十三五”城市空气质量评价分析

“十三五”是新疆经济、社会和环境发展的关键期.基于2015-2020年新疆14个城市空气质量年平均数据,采用三年滑动平均方法对新疆“十三五”空气质量进行评价分析.结果 表明:全区空气质量优劣依次是北疆＞东疆＞南疆,其中乌鲁木齐市三年滑动年均优良天数比例呈逐年上升趋势,而和田市与之相反,呈下降趋势,且三年滑动年均下降率达...     

Time Series Analysis to Monitor and Assess Water Resources: A Moving Average Approach

An understanding of the behavior of the groundwater body and its long-term trends are essential for making any management decision in a given watershed. Geostatistical methods can effectively be used to derive the long-term trends of the groundwater body. Here an attempt has been made to find out the long-term trends of the water table fluctuations of a river basin through a time series approach. The method was found to be useful for demarcating the zones of discharge and of recharge of an aquifer. The recharge of the aquifer is attributed to the return flow from applied irrigation. In the study area, farmers mainly depend on borewells for water and water is pumped from the deep aquifer indiscriminately. The recharge of the shallow aquifer implies excessive pumping of the deep aquifer. Necessary steps have to be taken immediately at appropriate levels to control the irrational pumping of deep aquifer groundwater, which is needed as a future water source. The study emphasizes the use of geostatistics for the better management of water resources and sustainable development of the area.     

2018年8月两次登陆北上台风移向的先兆信号分析

在分析台风“摩羯”（201814）和“温比亚”（201818）登陆北上异常路径的基础上,从近地面层气象要素场与台风位置动态配置入手,探寻了台风登陆后移向的近地面先兆信号,以此可修正数值模式的预报结果。主要结论如下:登陆后的台风尽管路径多变,但是近地面层气象要素还是会提供一些移向征兆。比如,地面3 h变压低值中心和地面露点高值中心,1 000 hPa高频流涡旋、渐近线或汇合点将是台风未来移动的方向;台风还有沿着流线密集带向其倒槽顶端移动的趋势。登陆后的台风没有趋暖性,而是沿地面温度低值区移动。由于地面要素受下垫面影响较为严重,所以在实际业务应用中应以地面3 h变压、地面露点与高频流场为主,地面温度和地面流场为辅。     

我国工伤事故死亡率分析及其ARIMA预测

对我国工伤事故死亡率的历史数据进行分析,介绍ARIMA模型预测法。根据统计学理论,运用ARIMA模型,借助相关软件预测我国工伤事故死亡率,可知未来几年,工伤事故的千人死亡率总体上呈逐年下降的趋势;与移动平均法、指数平滑法预测结果作比较,可知ARIMA模型预测效果最佳;同时,由于影响工伤事故的因素很多,与长期预测相比,ARIMA模型更适合于对工伤事故死亡率作短期预测。     

井下移动热源对巷道局部风流温度影响规律研究

为了研究煤矿井下热源对巷道局部风流温度的影响,通过搭建实验平台以及建立数值模型,采用实验和数值模拟的方法,分析井下固定和移动热源对巷道局部风流温度的影响规律。研究结果表明:对比实验和数值模拟固定热源对巷道局部风流温度的影响,结果显示二者总体温度变化趋势一致性较好,验证了数学模型的正确性;井下热源移动速度不同时,顺风移动速度越大,对巷道局部温度影响越大,且巷道局部温度相对升高;逆风移动速度越大,对巷道局部温度影响越小,且巷道局部温度相对降低。     

新型移动床膜生物反应器处理PVA废水的实验研究

将移动床生物膜反应器（MBBR）与膜生物反应器（MBR）有机结合,形成一体化式新型移动床膜生物反应器（M—MBBR）。采用M—MBBR对PVA废水的处理效果进行了研究,介绍了反应器的结构,并考察了水力停留时间、COD容积负荷及曝气量等操作条件对处理效果的影响。实验结果表明,在水力停留时间8h,气水比为120：1,COD容积负荷在1．4—2．8kg／（m^3·d）范围内变化时处理效果最佳且出水保持稳定。在此操作条件下,M—MBBR对PVA和COD的去除率可分别达到54％和69％左右。     

移动床生物膜反应器处理生活污水的研究

通过小试规模的移动床生物膜反应器(MBBR)处理陕西科技大学污水处理厂生活污水的实验研究,探讨了水力停留时间、冲击负荷、pH对反应器处理效果的影响。实验结果表明,在HRT为10 h,进水ρ(COD)为300 mg/L,ρ(NH3-N)为35 mg/L,填料体积填充率为35%,pH为7左右时,MBBR反应器对COD、TN的去除率分别为87.38%、68%。     

悬挂链脉动波式曝气系统及相关工艺的研究

曝气技术与设备一直是活性污泥处理工艺中的核心组成部分 ,但目前使用的曝气设备存在着诸多不足之处 ,影响了整个处理工艺的效果。悬挂链脉动波式曝气系统解决了长期困扰的问题。本文通过 3个部分分析了该技术的设备特点、工艺特点和经济性。通过对悬挂链移动曝气技术与设备的研究 ,为今后我国兴建污水处理厂提供了一条低投资、高效能的途径 ,使我国在较短时间内提高污水处理率成为可能