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1.
Air pollution has seriously endangered human health and the natural ecosystem during the last decades. Air quality monitoring stations (AQMS) have played a critical role in providing valuable data sets for recording regional air pollutants. The spatial representativeness of AQMS is a critical parameter when choosing the location of stations and assessing effects on the population to long-term exposure to air pollution. In this paper, we proposed a methodological framework for assessing the spatial representativeness of the regional air quality monitoring network and applied it to ground-based PM2.5 observation in the mainland of China. Weighted multidimensional Euclidean distance between each pixel and the stations was used to determine the representativeness of the existing monitoring network. In addition, the K-means clustering method was adopted to improve the spatial representativeness of the existing AQMS. The results showed that there were obvious differences among the representative area of 1820 stations in the mainland of China. The monitoring stations could well represent the PM2.5 spatial distribution of the entire region, and the effectively represented area (i.e. the area where the Euclidean distance between the pixels and the stations was lower than the average value) accounted for 67.32% of the total area and covered 93.12% of the population. Forty additional stations were identified in the Northwest, North China, and Northeast regions, which could improve the spatial representativeness by 14.31%.  相似文献   

2.
Snowmelt runoff is an important source of water resources in the arid mountain area. Modelling snowmelt runoff for cold regions remains a problematic aspect because of the lack of data by gauges in large basins. In order to overcome the shortage of measured data in the snowmelt runoff modelling, the temperature interpolation method would greatly help in improving the simulation accuracy and describing the snow-hydrological behaviours of the study catchments. In this study, the temperature is the principal variable used to estimate the importance of the melting of snow cover using the snowmelt runoff model. Five different temperature interpolation attempts were performed over the Kaidu River Basin for the snowmelt season of the year 2000. Three temperature inputs were taken directly from the individual weather stations in or near the study area, and the other two temperature inputs were interpolated from the three weather stations. The results indicated that the temperature estimated from different methods could result in quite a difference in runoffs in comparison with the observed ones. The simulation results using average temperature from the three stations showed good results; the simulation run with the weighted average temperature generated a lower R 2 than the average temperature of three stations and using temperature directly adopted from three individual stations gave various results. The weather stations used to perform the snowmelt runoff simulation should be located in the place which is most representative of the mountain weather conditions, and the land cover and topography that those stations represented also play an important role in the snowmelt runoff simulation.  相似文献   

3.
In the present study, trends of rainfall of the Central India were evaluated in monthly, seasonal, and annual time scales using the Revised Mann-Kendall (RMK) test, Sen’s slope estimator, and innovative trend method (ITM). For this purpose, the monthly rainfall data for 20 stations in Madhya Pradesh (MP) and Chhattisgarh (CG) states in Central India during 1901–2010 was used. The Sen’s slope estimator was utilized for calculating the slope of rainfall trend line. Based on the obtained results of RMK test, there is no significant trend in the stations for the January and October months. The results also showed that for MP, two out of 15 considered stations indicate significant annual trend, while the CG has four out of five stations with significant trend. The results of applying ITM test indicated that most of the stations have decreasing trends in annual (16 stations), summer (16 stations), and monsoon (11 stations) seasons, while the winter (12 stations) and post monsoon (11 stations) seasons generally show increasing trend. Unlike the RMK, the ITM shows significant increasing trend in rainfall of November and December months. The finding of current study can be used for irrigation and water resource management purpose over the Central India.  相似文献   

4.
In order to characterise the influence of the heavyrains on the observed landslides during the 1996–1997hydrological cycle, rainfall records for the last 100years are analysed from 104 stations in easternAndalusia. Regarding the amounts of rain recordedbetween October 1996 and March 1997 in the 104stations studied, 31 presented new all-time records;15 presented values that were 80–100% of thepre-1995 record; 49 stations, 80–50%; and 9stations, < 50%. A map has been devised of thesusceptibility of the materials through which thesouth-eastern Andalusian road network crosses,together with an inventory of the damage caused byinstability phenomena on banks and cuttings of theroad network during the winter of 1996–1997. Therelationships between the rainfall during the studyperiod, the damage caused to the road network and thesusceptibility of the materials affected are analysed.The results indicate that there is a clearcorrespondence between the rainfall recorded and thesusceptibility of the materials with the inventorieddamage. It is concluded that the widespread seriousdamage caused in early 1997 to the roads andsurrounding areas in the Alpujarra region and thecoast of the Province of Granada was mainly caused bythe extraordinarily heavy rains. However, considerablyless damage was observed where the susceptibility ofthe terrain is low, thus highlighting the extremeusefulness of terrain-susceptibility maps for riskprevention and territorial planning.  相似文献   

5.
为探讨不同测量站配置数对统计长江流域夏季日面雨量精度的影响,选取金沙江下游、鄂东北、青弋水阳江3个流域作为研究对象,并挑选出不同站网分布,统计各站网分布计算的2016—2018年夏季日面雨量,运用平均绝对误差（MAE）、均方差（MSE）和相关系数（r）三个技术指标来评价各流域夏季日面雨量精度与站数之间的关系。结果表明：各流域夏季日面雨量精度均受站数变化的影响,MAE、MSE均随站数的增加而减小,但当站数增加到一定数量之后趋于稳定,r也有相同的变化规律,只是随站数增加而增大。同时,通过计算三个技术指标随站数平均变化值,定量揭示了以上变化规律并得到金下、鄂东北、青弋水阳江流域代表性站数分别为405站、293站、126站,与现有站数相比,分别减少25.1%、55.8%、56.6%,可为计算长江流域夏季日面雨量选用站数和站网布局提供参考。  相似文献   

6.
杨森  张明军  王圣杰  王杰  陈荣  马荣  潘素敏 《冰川冻土》2017,39(5):1113-1121
基于中国自动气象站与CMORPH降水产品融合的0.1°×0.1°高分辨率逐时降水量网格数据集以及气象站点日降水的实测资料,对青藏高原面雨量的空间分布做了研究,并运用线性分析法对青藏高原季节面雨量和逐时面雨量的年际变化做了分析。结果表明：（1）0.1°×0.1°高分辨率格点降水数据能够准确地反映青藏高原面雨量的空间分布特征,东南缘的降雨量远大于西北部。格点数据与站点数据之间偏差率小于20%的站点占到站点总数（84个）的65.48%,相关系数大于0.9的站点有48个。（2）2008-2013年青藏高原总面雨量的年均值为133.42×1010 m3,夏季面雨量最大,占到全年面雨量的51.48%。四季面雨量均呈增长趋势,春、夏、秋、冬的线性倾向率分别为0.40×1010 m3·a-1、3.11×1010 m3·a-1、1.30×1010 m3·a-1和0.92×1010 m3·a-1。（3）面雨量峰值出现在19：00-20：00（北京时间,下同）,面雨量增多的时间出现在17：00-02：00。  相似文献   

7.
Precise Point Positioning (PPP) algorithms have been widely used in the Global Positioning System (GPS)-based applications. A PPP technique with a single receiver provides effective solutions where accurate absolute positioning is required. This paper provides the performance assessment of GPS PPP for detecting the displacements caused by an earthquake. For this purpose, the earthquake that occurred on 21 July 2017 at Kos-Bodrum with the impact of Mw 6.6 was investigated by analyzing the data of the permanent GPS stations located around the related region with the PPP technique. The location distances of these GPS stations range from 10 to 89 km to the epicenter of this earthquake. GPS data provided from seven permanent stations from the Continuously Operating Reference Stations-Turkey (CORS-TR) and local Bodrum CORS networks were processed to determine the co-seismic displacements during the earthquake. The data of these stations for days of year (DOYs) 200, 201, 202, and 203 were analyzed with post-process static PPP and kinematic PPP methods. GIPSY-OASIS II v6.4 was used for processing the data and all of the solutions were performed in the ITRF2008 reference frame. Two strategies were followed on the post-process static solutions. In the first strategy, 4-day data with 24-h observations were separately analyzed day by day. In the second strategy, the 24-h data were divided into 3-h duration, which is the minimum duration for optimum PPP solutions, and then the analyses were performed. When the displacements between DOYs 200 and 203 are considered in the 24-h data analysis, significant displacements have been observed through northwest direction in the northern stations whereas MUG1 is excluded. Moreover, there is significant displacement through the southeast direction in the station DATC located in the south of the epicenter. When the 3-h solutions are examined, displacements, especially on n and e directions, are observed starting from the solutions, which include Mw 6.6 earthquake. According to the kinematic PPP solutions, the effects of the Mw 6.6 earthquake can be seen clearly in the stations DATC, ORTA, TRKB, and YALI. Considering all outcomes, the PPP technique with both static and kinematic solutions provides effective results for detecting the displacements during the earthquake.  相似文献   

8.
In recent decades, the space geodesy has been applied to the areas such as transportation, infrastructure planning, navigation, etc. Among them, the precise positioning at the Global Navigation Satellite System (GNSS) stations yields better view in the understanding of the crustal deformation that requires global-scale measurements. There have been numerous studies examining the data process of continuous GNSS observations in the field of earth monitoring. More recently, GNSS stations established for continuously operating reference station networks have been beneficial resources in the tectonic plate-monitoring studies in lieu of campaign-type observations. However, this requires that the Continuously Operating Reference Station (CORS) should be established on stable structures acting like foundations and requires investigation of the long-term repeatability time series. This study aims to introduce recently established national CORS network, named CORS-TR, covering the entire Turkey and Northern Cyprus, and to explain the process of the long-term data obtained from the network on the characteristics of the tectonic plate movement within the area. The results of the CORS-TR data process present a great potential of using continuously operating reference stations not only in real-time kinematic applications of conventional geodesy studies but also in detecting and monitoring the crustal deformations of those that are crucial in earthquake-prone areas like Turkey. Since the findings are computed from the results of the all permanent stations of CORS-TR network, this study also examines the GNSS observation quality of the network for the given time interval. One of the major conclusions of the data process conducted in the study displays that the CORS-TR stations established on the carefully selected large and low-rise existing building had been more stable than the stations on the ground which have been subjected to soil settlement since the construction.  相似文献   

9.
Temporal changes of meteorological variables can affect reference evapotranspiration (ET0). The goal of the present research is to analyze the changes of ET0 and identify the impact of effective meteorological parameters to the changes of ET0. For this purpose, daily meteorological data recorded in 30 synoptic stations of Iran during 1960–2014 were used. The annual and seasonal values of ET0 were calculated by the recorded data. To calculate ET0, FAO56 Penman–Monteith method (standard method) was used. The annual and seasonal trends of ET0 and its eight effective parameters were analyzed. Then the contributions of effective parameters changes on ET0 were determined. To analyze ET0 trend at annual and seasonal scales, two common methods, Spearman’s Rho and Mann–Kendall tests, were used. The R 2 = 0.99 showed that the results of the mentioned methods were similar and on the basis of T-statistic <0.057, their difference was not significant (95% confidence level). Therefore, only one method’s results (Spearman’s Rho) were reported. On the basis of Spearman’s Rho results, the annual and seasonal values of ET0 had negative trend in most of arid and semi-arid stations while the trend of this parameter was positive in humid and very humid stations. At annual and seasonal scales, decreasing in wind speed (W), temperature (T), sunshine hours (n), minimum temperature (TN), dew point temperature (TD), maximum temperature (TX), saturation vapor pressure deficit (SVPD) and solar radiation (RS) was observed in 58, 54, 39, 43, 56, 65, 65 and 37% studied stations, respectively. In many scales, the results showed that TX and W were the most effective meteorological variables on ET0 changes and then SVPD was located in second step in arid and semi-arid stations. In humid and very humid stations, W was the first effective parameter at all scales, except autumn.  相似文献   

10.
适用于全国范围的水面蒸发量计算模型的研究   总被引：20，自引：1，他引：19  
李万义 《水文》2000,20(4):13-17,63
分析了水面蒸发的主要影响因素,并以此提出了一个基于水面蒸发物量过程的水面蒸发量计算模型。根据文献「１」给出的全国１９个蒸发实验站的资料和巴彦高勒蒸发实验站的资料,确定了模型中的参数。从而给出一个认为可以适用于全国范围的水面蒸发计算模型。将这一模型与文献「１」给出的全国两大气候区的６个模型进行了比较,并以巴彦高勒蒸发实验站的资料进行了检验,结论是本文给出的模型精度为高。  相似文献   

11.
青藏高原总辐射变化对高原季节冻土冻结深度的影响   总被引：6，自引：4，他引：2  
利用青藏高原及其毗邻地区22个辐射观测站建站至2000年的总辐射及日照百分率观测资料,确定了Angstrom-Prescott模型参数,以此模型估算了高原及毗邻地区116个站1961年1月至2000年12月份的总辐射.结合高原地区75个气象站的冻土观测资料,探讨了青藏高原地区总辐射变化对高原土壤季节冻结深度的影响.结果显示,冬季总辐射变化对季节冻深有较大影响.冷湖、玉树两个较典型的站点中总辐射与土壤冻结深度的负相关关系显著,与典型站点相似,德令哈、格尔木两站总辐射与季节冻深亦呈负相关.研究区域内,近乎80%的调查站点,总辐射与季节冻结深度之间关系呈现负相关;另外21%的站点呈现正相关关系.多元回归分析结果显示,纬度、海拔、总辐射及气温4个因子与季节冻结深度的相关显著.总辐射是高原土壤季节冻结深度的重要影响因子之一.  相似文献   

12.
基于我国南方地区岩溶发育极不均匀、水位水质动态变化快的特点,通过对信息熵法和防污性能法所得结果的对比,分析在缺少系列监测资料条件下,利用岩溶水系统防污性能评价结果快速布设地下河系统水动态监测网的可行性及其布设原则。根据防污性能评价结果,结合水循环特征,桂林海洋-寨底地下河系统水动态监测网需由17个监测站组成;采用信息熵法对现有35个监测站进行优化后,认为只需要12个监测站就可组成最优监测网,但这12个监测站点与采用防污性能评价法得到的点位完全重合,且均位于防污性能差的地区。对比分析认为,以地下水系统防污性能评价结果布设地下水动态监测网是可行性的,因为岩溶发育区既是防污性能差的地区,也是地下水动态变化快的地区,能充分反映地下河系统水质水量变化。采用防污性能评价法布设地下水动态监测网时,需要充分认识和了解地下河系统水文地质条件和地下河管道结构特征,且需要遵循以下原则:(1)在岩溶发育相对较弱的系统中部(基本上不存在防污性能差的地区)不设置监测站点;(2)在距离地下河出口较近的岩溶发育区内(即防污性能差的地区)监测站点可由地下河出口替代;(3)对于多支管道系统,岩溶发育相对较弱且距离较短的小型支管道上可以不布设监测站,由支管道与主管道交汇处的监测站代替。  相似文献   

13.
在海洋地区进行高质量的长期地震观测是全球地震观测的一个重要组成部分，DSDP／ODP是唯一能够钻穿软的沉积物、在坚硬的岩石里安置地震传感器这一目标的科学计划。介绍了ODP航次在井孔中设立地震台站、并获得一些有趣的结果的成功例子。ODP在日本外海布置了两个井中地震台站，与陆上台站一起来观测板块边界的活动性。此外，还介绍了西太平洋井中宽带台站、海上地震信号和噪音等问题。  相似文献   

14.
姜忻良  郑刚  侯树民  刘洪  崔奕 《岩土力学》2002,23(4):504-507
对天津市新建的地铁一号线中的既有线路车站新建与改造方案进行了分析，验算了改造过程中箱体施工阶段的强度，提出了几种改造方案与新旧结构的连接方法，并进行了计算分析与比较。最后，对新建与改造方案进行了经济比较，为有关部门提供了决策依据。  相似文献   

15.
In order to achieve a better understanding of the nature of the factors influencing ground water composition as well as to specify them quantitatively, multivariate statistical analysis (factor analysis) were performed on the hydrochemical data of this area. R-mode factor analysis was carried out on the geochemical results of the 79-groundwater samples and the factor scores were transferred to areal maps. Fundamental chemical parameters of the groundwater have been compounded together for characterizing and interpreting a few empirical hydrogeochemical factors controlling the chemical nature of water. R-mode factor analysis reveals that the groundwater chemistry of the study area reflects the influence of anthropogenic activities, silicate weathering reactions, precipitation, dissolution and subsequent percolation into the groundwater. The data have been put into few major factors and the seasonal variation in the chemistry of water has been clearly brought out by these factors. Factor scores were transferred to contour diagrams and the factor score analysis has been used successfully to delineate the stations under study with various factors and the seasonal effect on the sample stations.  相似文献   

16.
额尔古纳河流域近50年水文气象要素变化分析   总被引：2，自引：0，他引：2  
轩玮  李翀  赵慧颖  廖文根 《水文》2011,31(5):80-87
应用预置白处理后的Mann—Kendall非参数检验方法及小波分析方法,分析了额尔古纳河流域20个水文气象站点近50年水文气象要素(气温、降水和径流)的变化趋势以及典型站点降雨量、径流量的多时间尺度特征。同时应用聚类分析方法推算了径流量序列的突变点。结果表明,该区域气温呈现明显升高的趋势,其中海拉尔站可能由于城市化进程的影响气温升高幅度最大。流域年降水总量变化趋势不显著,但某些月份降水量存在明显增加或者减小的趋势,其中显著增加的月份为11、12和1月,显著减小的月份为7、8月;降水趋势显著变化的站点主要分布在该流域的呼伦湖水系和海拉尔河水系。流域年径流量有减少趋势但不显著,然而4、5月份大多数站点径流量出现显著减少趋势。小波分析表明,典型站点年降水量存在25a左右的主周期,年径流量存在20～26a的主周期。各个站点径流量序列的显著跳跃点大都发生在1999年,这与通过小波分析得出的有关突变点的结论相一致。  相似文献   

17.
Accurate estimation of low flow as a criterion for different objectives in water resource management, including drought is of crucial importance. Despite the complex nature of water deficits, univariate methods have often been used to analyze the frequency of low flows. In this study, low flows of Dez River basin were examined during period of 1956–2012 using copula functions at the upstream of headbranches’ junction. For this purpose, at first 7-day series of low flow was extracted at the studied stations, then their homogeneity was examined by Mann–Kendall test. The results indicated that 7-day low flow series of Dez basin were homogenous. In the next stage, 12 different distribution functions were fitted onto the low flow data. Finally, for Sepid Dasht Sezar (SDS), Sepid Dasht Zaz (SDZ), and Tang Panj Bakhtiyari (TPB) stations, logistic distribution had the best fit, while for Tang Panj Sezar (TPS) station, GEV distribution enjoyed the best fit. After specifying the best fitted marginal distributions, seven different copula functions including Ali–Mikhail–Haq (AMH), Frank, Clayton, Galambos, Farlie–Gumbel–Morgenstern (FGM), Gumbel–Hougaard (GH), and Plackett were used for bivariate frequency analysis of the 7-day low flow series. The results revealed that the GH copula had the best fitness on paired data of SDS and SDZ stations. For TPS and TPB stations, Frank copula has had the best correspondence with empirical copula values. Next, joint and conditional return periods were calculated for the low flow series at the upstream of branches’ junction. The results of this study indicated that the risk of incidence of severe drought is higher in upstream stations (SDZ and SDS) when compared with downstream stations (TPB and TPS) in Dez basin. Generally, application of multivariate analysis allows researchers to investigate hydrological events with a more comprehensive view by considering the simultaneous effect of the influencing factors on the phenomenon of interest. It also enables them to evaluate different combinations of required scenarios for integrated management of basin and planning to cope with the damages caused by natural phenomena.  相似文献   

18.
临近既有地铁车站的基坑变形性状研究   总被引：1，自引：0，他引：1  
朱炎兵  周小华  魏仕锋  谭勇 《岩土力学》2013,34(10):2997-3002
通过36组二维有限元数值模拟,研究了不同参数（基坑与地铁车站距离D,基坑开挖深度 ）组合下临近既有地铁车站的基坑变形性状,并与邻近无车站时的基坑变形性状进行对比分析。研究结果表明：（1）当邻近存在地铁车站时,靠近车站一侧的地下连续墙最大侧移量减小,另一侧的地下连续墙最大侧移量增加;（2）当基坑开挖深度接近或超过地铁车站底板埋深时,车站对远离车站侧的基坑墙后地表沉降的影响显著,但不明显改变地表沉降影响范围和最大沉降值位置;（3）D较小时,随着 的增大,地铁车站的“遮拦效应”越来越显著。而当D逐渐增大时, 对地铁车站“遮拦效应”的影响逐渐减弱。（4）地铁车站的存在与否对基坑远离车站侧最大地表沉降和最大地下连续墙侧移的比值（δevm / δehm）几乎没有影响,并且,该值受D与 的影响较小。  相似文献   

19.
沂沭河流域大型水库至下游控制站河道流量演算方案研究   总被引：1，自引：0，他引：1  
本文对沂沭河流域大型水库至下游控制站的河道流量演算方案进行了系统研究.文中根据马斯京根分段连续流量演算法原理.依据实测库、河中高水资料,分析确定了大型水库至下游控制站之间河段的特征河长及稳定流传播时间关系,建立了由水库泄洪最大流量和中游河道站洪峰流量推求河段代表流量的计算公式.使用本方案,可快速准确地将上游大型水库的泄洪流量过程汇流演算至下游控制站,能够有效提高下游控制站的洪水作业预报精度.  相似文献   

20.
淮河上游地区干旱评价分析   总被引：3，自引：0，他引：3  
利用淮河上游6个雨量站1964～2000年日降雨资料和邻近气象站气象资料,分别计算各站逐月Palmer干旱指标和雨量距平指标,并对计算结果进行对比分析.结果表明:淮河上游地区旱涝程度具有较强的持续性,夏季干旱多发,不过干旱等级多集中在轻微干旱和中等干旱;秋冬季节则是严重干旱多发的季节;极端干旱多发于春季;相比降雨量较大的淮南地区,淮北地区更为干旱.  相似文献   

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