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Middle and eastern routes of the South-North Water Diversion Project (SNWDP) of China, which are approximately located within the area 28°-42°N and 110°-122°E, are being constructed. This paper investigates the past climatic variations on various time scales using instrumental and proxy data. It is found that annual mean surface air temperature has increased significantly during the past 50-100 years, and winter and spring temperatures in the northern part of the region have undergone the most significant changes. A much more significant increase occurs for annual mean minimum temperature and extreme low temperature than for annual mean maximum temperature and extreme high temperature. No significant trend in annual precipitation is found for the region as a whole for the last 50 and 100 years, although obvious decadal and spatial variation is detectable. A seesaw pattern of annual and summer precipitation variability between the north and the south of the region is evident. Over the last 100 years, the Haihe River basin has witnessed a significant negative trend of annual precipitation, but no similar trend is detected for the Yangtze and Huaihe River basins. Pan evaporation has significantly decreased since the mid-1960s in the region in spite of the fact that the trend appears to have ended in the early 1990s. The negative trend of pan evaporation is very significant in the plain area between the Yangtze and Yellow Rivers. There was a notable series of dry intervals lasting decades in the north of the region. The northern drought of the past 30 years is not the most severe in view of the past 500 years; however, the southern drought during the period from the 1960s to the 1980s may have been unprecedented. The dryness-wetness index (DWI) shows significant oscillations with periodicities of 9.5 and 20 years in the south and 10.5 and 25 years in the north. Longer periodicities in the DWI series include 160-170- and 70-80-yr oscillations in the north, and 100-150-yr oscillations in the south. The observed climate change could have implications for the construction and management of the SNWDP. The official approval and start of the hydro project was catalyzed by the severe multiyear drought of 1997-2003 in the north, and the operation and management of the project in the future will also be influenced by climate change-in particular by precipitation variability. This paper provides a preliminary discussion of the potential implications of observed climate change for the SNWDP. [ABSTRACT FROM AUTHOR]

This paper is intended to give a survey of the main results of queueing theory in China. It consists of five parts: (1) the transient behaviour of typical queueing systems; (2) classical problems; (3) approximation theory; (4) model structure; (5) applications. [ABSTRACT FROM AUTHOR]

Traditional methods used to predict the ground-wave field strength at low frequency are not applicable for terrains with serious irregularities because of the analytical approximations. In this paper, the two dimensional finite-difference time-domain (FDTD) algorithm is applied to calculate the field strength of the low frequency (LF) ground wave propagating over irregular terrains. The propagation characteristics are studied as functions of the mountain's gradient, height, and width, respectively. We also focus on studying the cases with multiple mountains in the path. Moreover, the error of the traditional integral equation method is analyzed by comparisons. The results show that when the mountain's gradient and height are high, additional oscillations in the field strength will appear in front of and in the mountain region due to the wave reflection and scattering. At last, measurements of the Loran-C signals are taken along a real path between Pucheng and Tongchuan in Shaanxi province, China. It is found that most of the measured and FDTD results have good agreements while some still have big errors owing to the model approximation. The FDTD method gets better precision than the integral equation method in the irregular terrain. [ABSTRACT FROM AUTHOR]

The time-band approximation model for flight operations recovery following disruption (Bard, Yu, Arguello, IIE Transactions, 33, 931–947, 2001) is constructed by partitioning the recovery period into time bands and by approximating the delay costs associated with the possible flight connections. However, for disruptions occurring in a hub-and-spoke network, a large number of possible flight connections are constructed throughout the entire flight schedule, so as to obtain the approximate optimal. In this paper, we show the application of the simplex group cycle approach to hub-and-spoke airlines in China, along with the related weighted threshold necessary for controlling the computation time and the flight disruption scope and depth. Subsequently, we present the weighted time-band approximation model for flight operations recovery, which incorporates the simplex group cycle approach. Simple numerical experiments using actual data from Air China show that the weighted time-band approximation model is feasible, and the results of stochastic experiments using actual data from Sichuan Airlines show that the flight disruption and computation time are controlled by the airline operations control center, which aims to achieve a balance between the flight disruption scope and depth, computation time, and recovery value. [ABSTRACT FROM AUTHOR]

The tendency of labor turnover in the Chinese enterprise shows the characteristics of seasonal fluctuations and irregular distribution of various factors, especially the Chinese traditional social and cultural characteristics. In this paper, we present a coupled model for the tendency prediction of labor turnover. In the model, a time series of tendency prediction of labor turnover was expressed as trend item and its random item. Trend item of tendency prediction of labor turnover is predicted using Grey theory. Random item of trend item is calculated by artificial neural network model (ANN). A case study is presented by the data of 24 months in a Chinese matured enterprise. The model uses the advantages of "accumulative generation" of a Grey prediction method, which weakens the original sequence of random disturbance factors and increases the regularity of data. It also takes full advantage of the ANN model approximation performance, which has a capacity to solve economic problems rapidly, describes the nonlinear relationship easily, and avoids the defects of Grey theory. [ABSTRACT FROM AUTHOR]

This paper investigates the potential application of artificial neural networks in permanent deformation parameter identification for rockfill dams. Two kinds of neural network models, multilayer feedforward network (BP) and radial basis function (RBF) networks, are adopted to identify the parameters of seismic permanent deformation for Zipingpu Dam in China. The dynamic analysis is carried out by three-dimensional finite element method, and earthquake-induced permanent deformation is calculated by an equivalent nodal force method. Based on the sensitivity analysis of permanent deformation parameters, an objective function for network training is established by considering parameter sensitivity, which can improve the accuracy of parameter identification. By comparison, it is found that RBF outperforms the BP network in this problem. The proposed inverse analysis model for earth-rockfill dams can identify the seismic deformation parameters with just a small amount of sample designs, and much calculation time can be saved by this method. [ABSTRACT FROM AUTHOR]

The cloud-to-ground (CG) lightning data being detected by the China Lightning Detection Network between 2010 and 2013 are employed to gain insight into the spatial and temporal distribution of CG lightning in China. There are clear interannual and seasonal variations of CG lightning activity. The mean total CG and positive CG (PCG) flashes in 2010-13 are approximately 6.44 million and 0.42 million, respectively, and the mean percentage of PCG (PPCG) is 6.6%. CG and PCG flashes predominately occur during summer, with August being the peak month for CG and June for PCG. PPCG in the cold season is considerably greater than in the warm season; its maximum of 56.2% is in January and the minimum value of 4.0% is found in August. The centers of maximum mean annual CG density are scattered throughout southern China, the Sichuan basin, and the south of Jiangsu Province. The CG density in the high elevations and arid regions of western China is less than that in the low elevations and coastal regions of southeastern China. In addition, daily CG density and CG lightning days in southeastern China are greater than in northwestern China, but PPCG in western China is apparently greater than that in eastern China. Areas experiencing more than 30 CG lightning days per year are primarily south of 30°N, with 10-30 lightning days per year in northern and northeastern China, and approximately 10-20 lightning days per year over the central Tibetan Plateau. [ABSTRACT FROM AUTHOR]

The mainshock of April 20, 2013 Sichuan Lushan M7.0 earthquake was relocated using a 3-D velocity model. Double difference algorithm was applied to relocate aftershock sequences of Lushan earthquake. The locations of 2405 aftershocks were determined. The location errors in E-W, N-S and U-D direction were 0.30, 0.29 and 0.59 km on average, respectively. The location of the mainshock is 102.983°E, 30.291°N and the focal depth is 17.6 km. The relocation results show that the aftershocks spread approximately 35 km in length and 16 km in width. The dominant distribution of the focal depth ranges from 10 to 20 km. A few earthquakes occurred in the shallow crust. Focal depth profiles show fault planes dip to the northwest, manifested itself as a listric thrust fault. The dip angle is steep in the shallow crust and gentle in the deep crust. Although the epicenters of aftershocks distributed mainly along both sides of the Shuangshi-Dachuan fault, the seismogenic fault may be a blind thrust fault on the eastern side of the Shuangshi-Dachuan fault. Earthquake relocation results reveal that there is a southeastward tilt aftershock belt intersecting with the seismogenic fault with y-shape. We speculate it is a back thrust fault that often appears in a thrust fault system. Lushan earthquake triggered the seismic activity of the back thrust fault. [ABSTRACT FROM AUTHOR]

Emissions of reactive nitrogen (N) species can affect surrounding ecosystems via atmospheric deposition. However, few long-term and multi-site measurements have focused on both the wet and the dry deposition of individual N species in large areas of Northern China. Thus, the magnitude of atmospheric deposition of various N species in Northern China remains uncertain. In this study, the wet and dry atmospheric deposition of different N species was investigated during a three-year observation campaign at ten selected sites in Northern China. The results indicate that N deposition levels in Northern China were high with a ten-site, three- year average of 60.6 kgNha-1 yr-1. The deposition levels showed spatial and temporal variation in the range of 28.5-100.4 kgNha-1 yr-1. Of the annual total deposition, 40% was deposited via precipitation, and the remaining 60% was comprised of dry-deposited forms. Compared with gaseous N species, particulate N species were not the major contributor of dry-deposited N; they contributed approximately 10% to the total flux. On an annual basis, oxidized species accounted for 21% of total N deposition, thereby implying that other forms of gaseous N, such as NH3, comprised a dominant portion of the total flux. The contribution of NODue to image rights restrictions, multiple line equation(s) cannot be graphically displayed. to N deposition was enhanced in certain urban and industrial areas, possibly due to the fossil fuse combustion. As expected, the total N deposition in Northern China was significantly larger than the values reported by national scale monitoring networks in Europe, North America and East Asia because of high rates of wet deposition and gaseous NH3 dry deposition. Taken together, these findings show that NH3 emissions should be abated to mitigate high N deposition and associated potential impacts on ecosystems in Northern China. The present results improve our understanding of spatio-temporal variations of magnitudes, pathways and species of deposited N in the target areas, and are important not only to inform conservation and regulatory bodies but also to initiate further detailed studies. Uncertainties among current observations underscore the need to quantify the impact of vegetation on dry deposition and to refine the simulation of dry deposition velocity. [ABSTRACT FROM AUTHOR]

The quantitative reconstruction of the palaeoclimate is a prerequisite for understanding climate processes at time scales of centuries and millennia. Here, the coexistence approach (CA) was applied to reconstruct climatic factors quantitatively based on the fossil charcoal records between 5200 and 4300 cal yr BP in the Tianshui Basin, NW China. The CA analysis showed that the climate of the Tianshui Basin belonged to the northern subtropical zone between 5200 and 4300 cal yr BP. The mean annual temperature (MAT) was approximately 13.2 C, and the mean annual precipitation (MAP) was approximately 778mm between 5200 and 4900 cal yr BP. The MAT was approximately 13.2 C, and the MAP was approximately 688 mm between 4800 and 4300 cal yr BP. The MAT was approximately 2.2 C higher than today, and the MAP was approximately 280mm higher than today from 5200 to 4900 cal yr BP. The MAT was also approximately 2.2 C higher than today from 4800 to 4300 cal yr BP, while the MAP was approximately 196mm higher than today. No abrupt cold event occurred between 5200 and 4300 cal yr BP; however, a drought tendency appeared after around 4800 cal yr BP. [ABSTRACT FROM AUTHOR]

Daily precipitation data of 148 measuring stations in the Yangtze River basin (P.R. China) for the period from 1961 to 2002 have been analyzed to detect quasi periodicities in the frequency of occurrence of extreme precipitation events. Extreme precipitation events of duration 1-day and 10-day were defined in terms of 90th percentile threshold exceedances for each station. The time series were standardized, averaged and detrended for each subbasin. Distinct temporal agglomerations of Gaussian peaks in the smoothed time series for all subbasins were detected for certain years. Quasi periodicities features in the time series were analyzed by means of spectrum analyses. Characteristic differences were found for the subbasins with typical significant quasi periodicities in the 2–3 and 3–4 year ranges. Wavelet analyses revealed that the stability of the observed quasi periodicities over time also varied between the subbasins. This results in various degrees of confidence that can be placed on the future extrapolation of Fourier emulations. Our extrapolations suggest occurrences of peaks in the frequencies of extreme precipitation events for most subbasins around the years 2012–2013 and 2017–2018 even though major differences between the subbasins are expected. [ABSTRACT FROM AUTHOR]