Papers by Keyword: Rainfall

Abstract: The examination of the primary climatic indicators, air temperature and rainfall, at the Drobeta Turnu Severin meteorological station for the period 2011-2022, allowed for the identification of increasing or declining trends. The entire study was developed using three different time frames of analysis: monthly, seasonal, and annual. The results indicate the specificities for each climate parameter on each of the three-time scales. The yearly trends for mean temperature are primarily increasing, while the annual trends for rainfall are generally decreasing. Because of the fluctuation of meteorological elements, air pollution has varying characteristics based on the geographical and topographical qualities of the urban region. This study's findings help to understand the seasonality of the overall air quality and the interaction between meteorological conditions and air contaminants. The Air Quality Index (AQI) was used to assess air quality. The AQI revealed that the air quality in Drobeta Turnu Severin is normal.

Abstract: In this study an Artificial Neural Network for the simulation of flood phenomena in a natural area was developed. Then this network was implemented in the urban area of a Greek city (Amyntaio, Florina). The neural networks have many advantages: non-linearity, adaptability, input-output mapping, indicative response, damage resistance, possibility of implementation with VLSI (Very Large Scale Integration) technology, content related information and analysis and design uniformity. With neural networks, mathematical simulation of the considered phenomenon is not attempted, but the extraction of quantitative conclusions for specific data, based on similar cases. With the development and implementation of this network all the points that are in risk for flood are identified. The results showed that the help of an Artificial Neural Network in these cases is crucial for the future decisions in cases of flood phenomena.

Abstract: Short duration rainfall information has now become one of many important aspects to support the development of warning criteria for disaster mitigation. Similar importance is also found in the development of warning criteria against the lahar flow disaster at Mt. Merapi area. The rainfall information obtained from the radar observation has also become a new challenge for the last decade in line with the rapid growth of information and communication technology. However, the accuracy of its estimation needs to be evaluated by considering the correlation between radar rainfall and rain gauge rainfall. In case of radar rainfall can be precisely estimated, this information will contribute to generating appropriate warning criteria. This study was carried out as the first attempt to evaluate the rainfall information as performed by the X-Band Multi Parameter Radar (XMPR) that was installed at Mt. Merapi in the mid-August 2015. Several ground rainfall data obtained from Automatic Rainfall Recorder (ARR) have been adopted to analyze the aforesaid radar rainfall information, and estimated errors between the two are presented. Evaluation of the radar estimated error value as a function or range is taken through a Fractional Standard Error (FSE) index that quantifies the differences between ground rainfall measurement (G) and radar rainfall estimation (R), also the G/R ratio characteristics. The result shows there was a poor correlation between radar estimated and rain gauge measured rainfall located over 14 km from radar. Radar bias (M) is suitable for correcting radar rainfall amount, yet inappropriate for fractional values.

Abstract: Slope stability estimation is a complex engineering problem involving many factors. A hybrid model based on the combination of finite element software GEO-STUDIO and support vector machine (SVM) is proposed to address the problem. The study took a high slope of Jingjiang reach of Yangtze River as the research object. Several important parameters, including values of geometric and geotechnical properties of slope as well as rainfall and water level data were used to establish the finite element model for the high slope. Besides, the validity of the model was estimate using the measured data of pore water pressure. The slope stability coefficients were calculated in GEO-STUDIO environment. And the data were used as the input samples to train and test SVM model. Results show that the agreement achieved in pore water pressure between measurement and analysis using the finite element model can be considered very reasonable. And the slope stability coefficient results by SVM coincided well with that of finite element analysis. It suggests that the proposed model has the potential to be a useful tool for the prediction of slope stability coefficient considering the influence of rainfall and water level.

Abstract: Efforts in hydrometeorology are concentrated on finding the causes of the ground based radar uncertainty sources for rainfall estimation recently. The error sources are interactions between radar with atmosphere and topography. Radar singly often covers systematic error whereas atmospheric and topographic errors are relevant to location and precipitation pattern. This article reviews uncertainty sources on weather ground-based radar in order to rainfall estimation that have been discussed in nine main categories includes; the range effects, radar signal attenuation, beam blockage, vertical air motion and precipitation drift, ground clutter, anomalous propagation, vertical variability of the precipitation system, variability of the Z-R relationship and bright band. Topographic errors such as ground clutter and beam blockage primarily can be eliminated by attentive in site selection. Atmospheric errors such as vertical air motion and precipitation drift can filter or eliminated by calibration methods. Systematic errors include radar signal attenuation and anomalous propagation is the result of structural changes in the radar waves in space. Thus, this review is explored the characteristics of uncertainty error resources and a comprehensive appraisal of experimental procedures is provided.

Abstract: Water is fresh potable water is not always available at the right time or the right place for human or ecosystem use [1]. According to Straskraba and Tundisi (1999), water impoundments constructed by damming rivers are called dam reservoirs. Under the Malaysian Western Johore Agricultural Development Project, the main function of the Sembrong dam is flood mitigation. The secondary function of the dam is to provide clean water supply to 240,000 consumers in Kluang district area [2]. Water from the Sembrong dam reservoir is treated at the West Sembrong Water Treatment Plant before the distribution. Daily reservoir inflow data were extracted by applying the water balance model to the Sembrong dam reservoir. Developing hydrologic hazard curves for risk assessment uses the length of record and type of data to determine the extrapolation limits for flood frequency analysis [5]. Extrapolation beyond the data is often necessary to provide information needed for dam safety risk assessments [6]. The sources of information used for flood hazard analyses include stream flow and precipitation records and pale flood data.

Abstract: Study of sediment management is important to ensure the sedimentation process that occurred can be properly managed. Sediment have a positive correlation with the precipitation where, if the amount of precipitation is high then the sediment transport rate also will be increase. The additional of sediment into the river will shallow the river and lead to flooding. Thus, this analysis is carried out on the Batang Padang River to prove that there is a positive reaction by the precipitation and the amount of sediment, and will affect river management. The precipitation and sediment data from 1982 to 1996 were retrieved from Department of Irrigation and Drainage (DID) data base. Statistical analysis using the methods of correlation was used to determine the relationship between two variable has been prescribed. Based on the analyzed data, the highest value of rainfall was 3832.5 mm in 1988, and the highest value of sediment is 15331.9 tonnes/year was accured in 1985. Grade correlation is between 0:51 to 0.94 for observations fifteen years. Where the average grade of correlation that has been analyzed is 0.7. The results of the data analysis clearly shows that precipitation has a significant relationship with sediment.

Abstract: Rainfall-induced landslides occur in many parts of the world and causing a lot of the damages. For effective prediction of rainfall-induced landslides the comprehensive understanding of the failure process is necessary. Under different soil and hydrological conditions experiments were conducted to investigate and clarify the mechanism of slope failure. The failure in model slope was induced by sprinkling the rainfall on slope composed of sandy soil in small flume. Series of tests were conducted in small scale flume to better understand the failure process in sandy slopes. The moisture content was measured with advanced Imko TDR (Time Domain Reflectrometry) moisture sensors in addition to measurements of pore pressure with piezometers. The moisture content increase rapidly to reach the maximum possible water content in case of higher intensity of rainfall, and higher intensity of the rainfall causes higher erosion as compared to smaller intensity of the rainfall. The controlling factor for rainfall-induced flowslides was density of the slope, rather than intensity of the rainfall and during the flowslide the sudden increase in pore pressure was observed. Higher pore pressure was observed at the toe of the slope as compared to upper part of the slope.

Abstract: Shanxi is one of the typical loessial areas in China, accompanied by plenty of loess geological disasters induced by rainfall. Based on the survey and compartment of geological disasters in the area, the geological conditions of them have been obtained by anglicizing the landslide, the mud-rock flow and dilapidation that have occurred. What’s more, the geological conditions, growing characteristics, and distribution law of these geological disasters induced by rainfall were summarized. On that basis, targeted preventive measures were put forward. These will provide reliable support to loess geological disaster warning work and to confirm the mechanism of hazard forming study.

Abstract: Most failures of hydraulic engineering caused by hydrology events are rarely a function of just one source variable (e.g.wave,tide level,river flow,rainfall),but more usually of two or more variables.So,the correlation of two variables which are partially dependent is important for hydrologic design and floodplain management.The objective of this paper is to discuss the correlation degree between two variables by kendall's rank correlation coefficient test.As a case,the observations of rainfalls, tide levels and wind speeds,collected from 1971 to 2002 in Shenzhen city of China,were used in this paper.The results show that kendall’s rank correlation coefficients obtained by the test range from 0.13 to 0.61.This means that there is a significant correlation between any two of these hydrologic variables.