Comparison of grey and phase-space rainfall forecasting models using a fuzzy decision method / Comparaison grâce à une méthode de décision floue des modèles gris et d’espace des phases pour la prévision de pluie

Abstract

Abstract This work applies a fuzzy decision method to compare the performance of the grey model with that of the phase-space model, in forecasting rainfall one to three hours ahead. Four indices and two statistical tests are used to evaluate objectively the performance of the forecasting models. However, a trade-off must be made in choosing a suitable model because various indices may lead to different judgements. Therefore, a fuzzy decision model was applied to solve this problem and to make the optimum decision. The results of fuzzy decision making demonstrate that the grey model outperforms the phase-space model for forecasting one hour ahead, but the phase-space model performs better for forecasting two or three hours ahead.     

Analysis of a large inter-basin water transfer system in India / Analyse d’un grand système de transfert d’eau inter-bassins en Inde

Abstract

Abstract Inter-basin transfer of water in India is a long-term option to correct the spatial and temporal mismatch of water availability and demand, largely owing to the monsoon climate. This paper is concerned with analysis and preliminary design of a large inter-basin water transfer system in peninsular India. The system covers four major basins and involves operation of 13 major structures. The study was carried out in three stages. First, the surface water deficit in each basin was estimated. Then the net deficit was worked out by considering the availability of groundwater. Finally, the link systems were planned to transfer the amount of water needed to meet the demands with desired reliability.     

4. Hydraulics

Abstract

A solid state event recorder and reader suitable for use with a tipping bucket raingauge are described. The recorder is a small battery operated unit with very low power consumption, capable of recording 64, 8 bit, words. The portable reader unit is used to interrogate it.     

中国应对多边投资协议谈判的策略研究

经济全球化使得在投资领域制订多边投资协议势在必行。无论是从国际投资领域面临的新形势,还是考虑到自身利益和国策看,中国都应把握主动,积极促成多边投资协议谈判。     

“一带一路”沿线重点省份旅游经济高质量发展研究

从旅游资源转换效率的视角,以“一带一路”沿线18个重点省份为研究靶区,运用修正的DEA模型等方法探究2008—2017年的旅游经济增长质量的时空演变及发展趋势。研究结论有：① 10 a间,18个重点省份旅游资源转换效率均值仅为0.312,远未达到生产前沿面。② 经过邹检验（Chow test）,2014年为“一带一路”沿线18个重点省份旅游资源转换效率时间序列的突变点。③ 18个重点省份的旅游资源转换效率均存在σ收敛、绝对β收敛和条件β收敛;开放先行区、战略支点区未通过σ收敛检验、战略支点区未通过绝对β收敛。     

Sécheresse et modification de la relation pluie–débit: cas du bassin versant de l’Oued Sebdou (Algérie Occidentale)

L’objectif de ce travail est d’étudier les variations temporelles hydrométéorologiques et d’identifier les tendances dans la relation pluie–débit du bassin versant de l’Oued Sebdou, un sous bassin de la Tafna, situé dans le Nord-Ouest algérien. A partir des données pluviométriques (1941–2012) et hydrométriques (1972–2012), des tests statistiques ont permis d’identifier les ruptures et évaluer les déficits hydrométéorologiques. Les résultats ont révélé une modification du régime des précipitations se traduisant nettement par une tendance à la baisse survenue au milieu des années 1970, soit une réduction de 25%. En outre, la réduction des écoulements durant une période de 40 ans dépasse 58% avec une rupture décelée au début des années 1980. L’identification des tendances dans la relation pluie–débit a été menée par l’application de l’approche des simulations croisées à partir du modèle GR2M sur plusieurs sous-périodes de cinq ans. Une non-stationnarité de la relation pluie–débit a été mise en évidence durant la période 1985–2004, ce qui indique une tendance à la baisse des lames d’eau mensuelles écoulées sur le bassin versant de l’Oued Sebdou.     

Detection of trends in the 7-day sustained low-flow time series of Irish rivers

A combination of statistical hypothesis testing methods (Mann-Whitney, Mann-Kendall and Spearman’s rho) and visual exploratory analysis were used to investigate trends in Irish 7-day sustained low-flow (7SLF) series possibly driven by changes in summer rainfall patterns. River flow data from 33 gauging stations covering most major Irish rivers were analysed, after excluding catchments where low flows are influenced by significant human interventions. A statistically significant increasing trend in the 7SLF series was identified by all three tests at eight gauging stations; in contrast, a statistically significant decreasing trend was identified by all three tests at four stations. The stations with increasing trends are mainly located within the western half of the country, while there is no particular spatial clustering of the stations showing a decreasing trend. Further analysis suggests that the increasing trend in the 7SLF time series persists regardless of the starting year of analysis. However, the decreasing trend occurs only when years prior to 1970 are included in the analysis, and disappears, or is reversed, if only the data from 1970 and onwards are considered. There is strong evidence that the direction of the trends in the 7SLF series is determined mainly by trends in total summer rainfall amounts, i.e. is linked to weather.

EDITOR Z.W. Kundzewicz

ASSOCIATE EDITOR not assigned     

A two-step sensitivity analysis for hydrological signatures in Jinhua River Basin,East China

Parameter calibration and sensitivity analysis (SA) are usually not straightforward tasks for distributed hydrological models, owing to the complexity of models and the large number of parameters. A two-step SA approach is proposed for analysing hydrological signatures based on the distributed hydrology–soil–vegetation model (DHSVM) in the Jinhua River Basin, East China. A preliminary SA is conducted to obtain influential parameters via analysis of variance. These parameters are further analysed through a variance-based global sensitivity analysis method to achieve robust rankings and parameter contributions. Parallel computing is designed to reduce the computational burden. The results reveal that only a few parameters are significantly sensitive and that interactions between parameters cannot be ignored. When analysing hydrological signatures, it is found that water yield is simulated very well for most samples. Small and medium floods are simulated very well, while slight underestimations happen for large floods.     

西安市植被覆盖度与城市地表温度的关系研究

基于2017年4月陕西省西安市的Landsat8遥感数据,对西安市植被覆盖度与地表温度之间的相关性进行了回归分析.结果 表明,植被覆盖度与地表温度之间存在显著的负相关关系,植被覆盖度越低,地表温度越高,反之亦然.统计结果表明,地表NDVI每降低0.1,地面温度约升高3.3℃,因此在城市生态环境规划和建设中,可通过增加城...