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Spatial information technology in flood early warning systems: An overview of theory, application and latest developments in Malaysia
Abstract
Malaysia experiences a major flood event every three years due to the adverse effects of two monsoon seasons a year. Floods have thus become the most significant natural disaster in the country in terms of the population affected, frequency, aerial extent, financial cost and the disruption to socio-economic activities. Many previous flood control measures have had different levels of success but have generally had little effect in reducing the problem. However, it is now understood that it is neither possible nor desirable to control floods completely. Spatial information technology is thus being increasingly recognized as the most effective approach to flood disaster management. This paper reviews the spatial information technology in flood disaster management and its application in Malaysia. Some flood forecasting systems are discussed, along with their shortcomings. The paper discusses the framework of a proposed flood early warning system for the Langat river basin that operationally couples real-time NOAA-AVHRR data for quantitative precipitation forecasting with hydrologically oriented GIS and a MIKE11 hydrodynamic model.
... Most research on FLEWS or flood forecasting is done by constructing models of hydrological processes. Previous studies on FLEWS focused on rainfall-runoff models; see [12] for worldwide EWS review and reference [13] for Malaysia EWS review. The current research trend is to integrate new techniques into rainfall-runoff models. ...
... In this paper, we consider the CSD approach to construct a FLEWS using water level data. As a case study, we analyze the time series data of the daily water level at the Guillemard Bridge station, Kelantan River, Malaysia, from 1 January 2000 to 13 October 2010. Based on the time series of water level data, we calculate the CSD indicators and inspect the increasing pattern. ...
... EWS is a tool consisting of a series of mechanisms and procedures for detecting hazards, monitoring indicators, warning communications, and alarms. A study has been conducted to provide efficient EWS [12,13]. However, developing an EWS based on real data is challenging and may lead to false-positive results as well as false-negative results. ...
The theory of critical slowing down (CSD) suggests an increasing pattern in the time series of CSD indicators near catastrophic events. This theory has been successfully used as a generic indicator of early warning signals in various fields, including climate research. In this paper, we present an application of CSD on water level data with the aim of producing an early warning signal for floods. To achieve this, we inspect the trend of CSD indicators using quantile estimation instead of using the standard method of Kendall’s tau rank correlation, which we found is inconsistent for our data set. For our flood early warning system (FLEWS), quantile estimation is used to provide thresholds to extract the dates associated with significant increases on the time series of the CSD indicators. We apply CSD theory on water level data of Kelantan River and found that it is a reliable technique to produce a FLEWS as it demonstrates an increasing pattern near the flood events. We then apply quantile estimation on the time series of CSD indicators and we manage to establish an early warning signal for ten of the twelve flood events. The other two events are detected on the first day of the flood.
... Flood control necessitates collaboration between responsible authorities and the community for flood management phases to be addressed fairly Khalid & Shafiai, 2015). (Billa et al., 2004;Katuk et al., 2009;Ismail et al., 2012;Elias et al., 2013;Khalid & Shafiai, 2015). The Malaysian government is now taking a proactive approach, and the major floods that hit the country in 2014 on the East Coast prompted the government to establish the National Disaster Management Agency (NADMA) under the Prime Minister's Department, taking over disaster management from the National Security Council. ...
... Each agency has distinct tasks and approaches to various situations. Typically, during the prevention/mitigation phase, the Department of Irrigation and Drainage is the most important agency in charge, and this agency has implemented a comprehensive flood control and mitigation program (Billa et al., 2004;Ismail et al., 2012). However, according to Othman et al (2014), most agencies are frequently focused on disaster-related operations such as warning, immediate relief, and rehabilitation. ...
... Flood control necessitates collaboration between responsible authorities and the community for flood management phases to be addressed fairly Khalid & Shafiai, 2015). (Billa et al., 2004;Katuk et al., 2009;Ismail et al., 2012;Elias et al., 2013;Khalid & Shafiai, 2015). The Malaysian government is now taking a proactive approach, and the major floods that hit the country in 2014 on the East Coast prompted the government to establish the National Disaster Management Agency (NADMA) under the Prime Minister's Department, taking over disaster management from the National Security Council. ...
... Each agency has distinct tasks and approaches to various situations. Typically, during the prevention/mitigation phase, the Department of Irrigation and Drainage is the most important agency in charge, and this agency has implemented a comprehensive flood control and mitigation program (Billa et al., 2004;Ismail et al., 2012). However, according to Othman et al (2014), most agencies are frequently focused on disaster-related operations such as warning, immediate relief, and rehabilitation. ...
... Di samping itu, banyak kajian literatur telah menjelaskan bahawa bencana lebih cenderung berlaku di kawasan bandar malah kesannya adalah lebih signifikan (Bendimerad, 2003;Bull-Kamaga et al., 2003;Wisner et al., 2003;Khailani & Perera, 2013). Dalam Satterthwaite et al. (2007), kawasan bandar ditafsirkan sebagai rumah kepada sebahagian besar populasi di dunia, aktiviti-aktiviti ekonomi dan infrastruktur fizikal yang sudah sedia ada berisiko bahaya dan kemudiannya dijangka akan bertambah serta bertukar menjadi bencana. ...
... Secara amnya, DSS adalah sistem sampingan yang digunakan untuk menyokong keputusan pengurusan dengan bantuan pelbagai teknologi geospatial moden seperti teknologi penderiaan jauh (Remote Sensing), Sistem Maklumat Geografi (GIS), kartografi, pengukuran dan pemetaan dan fotogrametri (Billa et al., 2004;Chang, 2012). Namun, dalam kajian ini, teknologi GIS akan diberikan keutamaan. ...
... Los SAT suelen establecer un sistema de alerta de la población basado en una escala simple (Semáforo Emergencia) que procura un máximo entendimiento por parte de la población afectada de la situación en la que se encuentran (Figura 2.51). Billa (BILLA, MANSOR, et al., 2004) sugiere un método de alerta temprana para las inundaciones basado en tecnologías de la información geográfica (SIG y Teledetección) y modelos predictivos para una región de Malaysia (Langat river basin). ...
... En especial el NOAA plano y geoestacionario proporciona cobertura del tiempo diaria en gran parte del mundo. Existen técnicas de predicción de formación de nubes y precipitación (BILLA, MANSOR, et al., 2004) Showalter realiza un análisis sistemático de la aplicación de la teledetección en el ámbito del peligro y la investigación de los desastres. Concluye que la teledetección es una técnica usada para detectar, identificar, cartografiar, inventariar y monitorizar los peligros existentes y sus efectos. ...
... Di samping itu, banyak kajian literatur telah menjelaskan bahawa bencana lebih cenderung berlaku di kawasan bandar malah kesannya adalah lebih signifikan (Bendimerad, 2003;Bull-Kamaga et al., 2003;Wisner et al., 2003;Khailani & Perera, 2013). Dalam Satterthwaite et al. (2007), kawasan bandar ditafsirkan sebagai rumah kepada sebahagian besar populasi di dunia, aktiviti-aktiviti ekonomi dan infrastruktur fizikal yang sudah sedia ada berisiko bahaya dan kemudiannya dijangka akan bertambah serta bertukar menjadi bencana. ...
... Secara amnya, DSS adalah sistem sampingan yang digunakan untuk menyokong keputusan pengurusan dengan bantuan pelbagai teknologi geospatial moden seperti teknologi penderiaan jauh (Remote Sensing), Sistem Maklumat Geografi (GIS), kartografi, pengukuran dan pemetaan dan fotogrametri (Billa et al., 2004;Chang, 2012). Namun, dalam kajian ini, teknologi GIS akan diberikan keutamaan. ...
The main purpose of this study is to analyse the geomorphological charactertistics of the Dong Van Karst Plateau Geopark (DVKPG) in the Ha Giang province of Vietnam. A digital elevation model (DEM) was generated using SPOT5 imagery and elevation and slope maps were then extracted from the DEM. A geological map at the scale of 1:200,000 was constructed and used for analyzing and visualizing the carbonate rock in three dimensions. The results show that there are two types of topographic development in the study area. The first, formed by tectonic movement and affected by major faults, is distributed in a NW–SE direction. The second was formed by exogenous geomorphological processes and influenced by both major and faults. It is distributed mainly in a NE–SW direction. Geological analysis indicates that ten stratigraphic formations crop out in the study area but only six of these have correlations with karst landscapes. Carbonate rocks are mainly distributed in the Dong Van district. They cover an area of 329.7 km2 (71.7% of the entire district and 36.5% of study area). In constrast, there is few carbonate rocks in the Quan Ba district. In the case of slope, the slope angels from 15–30° cover about 53.5% of the study area. There are 1261 karst sinkholes in the study area with an average density of 1.4 sinkholes per km2.
... They must be better equipped with simplified but informative and understandable information to enhance their competence in the decision-making process in managing hazards. Geo-Information technology comprising of Geographic Information System (GIS), Remote Sensing, Global Positioning Systems (GPS), Digital Photogrammetry, and Surveying and Mapping [11], [12]. These technologies have shown rapid development over the years and have been used in diverse array of fields including disaster management and research. ...
... GIS is often found at its potential for mapping spatial data processing and visualizing meaningful information. Further explanation about the usability and potentials of GIS is discussed in [11], [13], [15], and many others. ...
The escalating impact of the disasters that occur in urban areas requires significant attention and planning in order to minimize vulnerability and disaster risk. However, efforts made to minimize disaster risk involves various disciplines, and can be viewed from numerous perspectives that need to be addressed in an integrated manner, and then effectively formulated to provide long term benefit. With the great potential of the GIS, incorporating both the physical and social aspects associated with disasters to reduce vulnerability will form a
comprehensive disaster management operation. Therefore, this study aims to translate various hazardous information that is physical and socio-economic in nature into a comparable layer within a GIS platform to assess the study area in an integrated manner. We have conducted a study in the Upper-Langat river basin, Peninsular Malaysia, which has been experiencing numerous disasters including floods and landslides. A hazard
assessment was conducted to: systemize the intricacy of the geodata, identify the predisposing and triggering factors associated with natural hazards, and integrate them spatially to derive multi-hazards data for effective hazard management. The findings revealed that spatially explicit data and maps at the relevant scale based on the surface and subsurface information, integrated with socio-economic vulnerabilities, provide better results that might be beneficial for multi-disaster risk reduction operations. It is also evident that the GIS has the sufficient
capacity to translate various physical, compositional, and socioeconomic aspects to the comparable outputs. Such spatially explicit products will expedite the decision making process for disaster risk reduction operations.
... Strategic disaster management cycle involves four steps: prepared before disaster, preparation of the arrival, when disaster emergency response and disaster recovery (Tingsanchali, 2012). Disaster management includes the implementation of flood forecasting, early warning, decision making, experts in preventing catastrophic problems (Billa, Mansor & Mahmud, 2004). Billa, Shattri, Mahmud, and Ghazali (2006) explained that the disaster management strategy has two important stages. ...
... Hence, this conceptual paper also suggests to fill the gap in flood disaster in Malaysia. Flood disaster in Malaysia is the phenomenon of the monsoons occurs twice in a year with the East monsoons occur from November to March and the South Monsoon winds also occur from May to September (Billa, Mansor & Mahmud, 2004). Chan and Parker (1996) mentioned that the floods in Malaysia occurred when East monsoon winds that often produce heavy rain over a long period around the Titiwangsa range. ...
This paper intends to establish a conceptual framework and discuss theoretical issues related to understanding relationships between source credibility, risk communication and well-being in disaster management context. The key aim of the framework is to highlight the relationship between the variables in predicting well-being in Malaysian contexts. Few literature on source credibility, risk communication and well-being that constitute the building blocks of this model were discussed as the starting point for general framework. This concept paper discusses the relationships between variables and proposed an integrated model of the conceptual framework between the variables to fill in the gap identified from previous studies to establish a new context of disaster management.
... In the same way that a two-dimensional, paper-and-pencil drawing captures the essence of a physical design, interaction design wireframes are meant to vividly represent the essence of an interaction design [11]. There have been many cases of using these approaches in terms of human-computer interaction and flood prediction and warning systems [12][13][14][15][16]. The use of different technologies in order to accomplish this is another important task. ...
This article discusses the design, development, and usability assessment of a mobile system for producing hydrological predictions and sending flood warnings in response to the desire for human-centered technology to better the management of flood occurrences. Our work acts as a bibliographic reference for understanding what others have attempted and found, as well as gives an integrated set of recommendations. Furthermore, our guidelines offer guidance to aid in the design of mobile GIS-based hydrological models for mobile devices. We concentrate on the full design of a human–computer interaction framework for an effective flood prediction and warning system. In addition, we analyze and address the current user needs and requirements for building a user interface for mobile real-time flood forecasting in a methodical manner. Although a functional prototype was created, the primary objective of this research was to comprehend the complexity of possible users’ demands and actual use situations in order to solve the problem of comparable systems being difficult to use. After consulting with possible consumers, application design standards were established and implemented in the initial prototype. Focusing on user demands and attitudes, special consideration was given to the usability of the mobile interface. To develop the application, a variety of assessment methods are added. The conclusion of the examination was that the system is efficient and effective.
... There is no doubt that precipitation patterns have changed globally in recent. In Malaysia and some Southeast Asian countries, increasing intensities of rainfall during the monsoons are not only a source of major flood but also a triggering cause of major landslide event [12]. ...
The main concern for this research is slope estimation and the beach profiling with verification sensor-based remotely data (high spatial resolution). Thus, surveying and satellite extraction data need to be accurat. It had been proven to support the relationship between coastal erosion with beach slope changes along Kuantan, Pahang. Therefore, the actual coastline can be mapped from last vegetation features and determine physical condition of beach on coastal habitable land where the baseline has been changes due to sea-level rise event. Hence, the aim of this study is to monitor beach profile using high spatial resolution remote sensing imagery and GIS techniques to distinguish slope estimation from different sources in Kuantan, Pahang Site-verification are done to identify beach slope profiling along Kuantan coastline, Pahang. The objectives of this research are i) to generate coastal slope estimation and beach profile in year 2006 and 2014, ii) to quantify the estimated and observed beach slope from IFSAR data and slope site surveying (by NAHRIM) and iii) to visualise in 3-D view of coastal slope profile derived using IFSAR data. The accuracy values provided for the measurements made in open area, undisturbed area with slopes less than 10 %. From early reconnaissance of Kuantan beach, most of the area are flat and sandy profile to which are suitable for this application. Besides, we found out this method are reliable to produce appropriate slope profile along identified areas in selected Pahang coastline. The findings may indicated a better strategy for monitoring coastline changes is needed especially for vulnerable coastal erosion areas for future sustainable coastal management.
... Iqbal et al. [17] reviews articles on computer vision applied to different phases of management and planning after a flood. A few papers like [18][19][20] present early warning systems devised for flood management. ...
After the occurrence of a natural disaster, it is of paramount importance to take efficient measures to reduce the casualties and damage to infrastructure. Resource allocation is a generic problem of assigning available resources to the affected areas to cope with the devastation caused by the disaster. To mitigate the deadly effect of a natural disaster, different resources are essential at the emergency sites. Disaster response activities also need the assignment of various critical tasks to be carried out by different emergency workers at the local level. The individual emergency locations convey their demands for resources and required services to the higher-level authorities. Depending on availability, the higher-level authority allocates resources through successive lower levels to the emergency sites. This paper proposes a model for the hierarchical flow of different resources during disaster management in the Indian context, from the top-level authority to the lower levels. This hierarchical architecture also incorporates the allocation of different essential tasks at the ground level to reduce the effect of a natural disaster locally.
... NAHRIM [6], on the other hand, forecasted a substantial increase (11 to 43%) in mean monthly rainfall over the area of the east coast of Peninsular Malaysia, while Moyawa et al. [7], who conducted a study on 54 stations along the east coast region of Peninsular Malaysia, reported that the heavy rainfall in the studied areas increased by 1.5 days per decade over the time period from 1971 to 2010. Regarding extreme events in Malaysia, Billa et al. [8] reported an increase of rainfall intensities during ...
This study aims to examine the mediating effect of climate resilience on the relationship between socio-economic, social relationship, social environment, and sense of community with fishermen’s subjective well-being (life satisfaction, positive feeling, and negative feeling). This quantitative study performed a multi-stage sampling and selected 400 fishermen as respondents. For analysis purpose, this study relied on Partial Least Square Structural Equation Modelling (PLS-SEM). The structural model concluded that socio-economic, social relationship, social environment, and sense of community explained 55.4% variance in resilience. The mediating analysis confirmed the resiliency mediating effect on all twelve hypothesized relationships. A number of recommendations related to extending the areas of the study, to focus specifically on the small-scale fishermen, and to consider the inclusion of several others’ additional mediating effects were highlighted.
... Over the period of last 100 years, 30% of the total reported disasters are reported due to floods which claimed more than 19% of the total deaths due to flood and more than 48% of total affected public are affected due to floods 2 . By 2050, about two billion people will be added in the list of people affected by flood disasters globally 3 . The losses will increase in the future due to the development of cities in the floodprone areas, rising sea level, climate change, deforestation and change in land-use 4 . ...
Most of the natural disasters are unpredictable, but the most frequent occurring catastrophic event over the globe is flood. Developing countries are severely affected by the floods because of the high frequencies of floods. The developing countries do not have good forecasting system compared to the developed country. The metro cities are also settled near the coast or river bank which are the most vulnerable places to floods. This study proposes plan for street level flood monitoring and warning system for the Surat city, India. Waterlogging happens in the low lying area of the Surat city due to heavy storm and heavy releases from the Ukai dam. The high releases from upstream Ukai dam and heavy rainfall resulted into flooding in the low lying area of the Surat city. This research proposed a wireless water level sensor network system for the street water level flood monitoring. The system is proposed to monitor the water levels of different areas of city through the wireless water level sensors as well as to capture live photos using CCTV camera. This will help authority not only to issue flood warning but also to plan flood mitigation measures and evacuation of people.
... The increasing amounts of data on the internet make it easy for attackers to manipulate the data and scam others. For example, a case study from Texas in 2013 proved that IoT could be manipulations, as the researchers used it for hijacking a yacht in the Mediterranean Sea, worth 80 million US dollars simply by manipulating the GPS that was being used by the yacht for directions (Billa et al., 2004). This points towards the weaknesses that can be potentially be used in a threatening way. ...
Integrating disruptive technologies within smart cities improves the infrastructure needed to potentially deal with disasters. This paper provides a perspective review of disruptive technologies such as the Internet of Things (IoT), image processing, artificial intelligence (AI), big data and smartphone applications which are in use and have been proposed for future improvements in disaster management of urban regions. The key focus of this paper is exploring ways in which smart cities could be established to harness the potential of disruptive technologies and improve post-disaster management. The key questions explored are a) what are the gaps or barriers to the utilization of disruptive technologies in the area of disaster management and b) How can the existing methods of disaster management be improved through the application of disruptive technologies. To respond to these questions, a novel framework based on integrated approaches based on big data analytics and AI is proposed for developing disaster management solutions using disruptive technologies.
... For the period from November to March, seasonal floods usually occur during the North-East Monsoon season while Southwest Monsoon occur from May to September. The two inter-monsoon period, in April and October are normally interested by variable wind and thunderstorm in the afternoon [2]. The heavy rainfall and the high concentration of runoff are the main reasons that cause flood in Malaysia. ...
... Hydrologists have long studied FLEWSs or attempted to forecast floods by constructing models of hydrological processes. An excellent review on worldwide FLEWS issues and techniques can be found in Ref. 1 and Malaysia FLEWS in Ref. 2 . ...
Flood early warning systems (FLEWSs) contribute remarkably to reducing economic and life losses during a flood. The theory of critical slowing down (CSD) has been successfully used as a generic indicator of early warning signals in various fields. A new tool called persistent homology (PH) was recently introduced for data analysis. PH employs a qualitative approach to assess a data set and provide new information on the topological features of the data set. In the present paper, we propose the use of PH as a preprocessing step to achieve a FLEWS through CSD. We test our proposal on water level data of the Kelantan River, which tends to flood nearly every year. The results suggest that the new information obtained by PH exhibits CSD and, therefore, can be used as a signal for a FLEWS. Further analysis of the signal, we manage to establish an early warning signal for ten of the twelve flood events recorded in the river; the two other events are detected on the first day of the flood. Finally, we compare our results with those of a FLEWS constructed directly from water level data and find that FLEWS via PH creates fewer false alarms than the conventional technique.
... This significant weather condition is caused by the Sumatra squall line which brings in heavy rain not only to Malaysia but also to Singapore (Yi & Koh., 2007). Meanwhile, rapid land-use changes such as urbanization and deforestation in the region are regarded as human factors that intensify floods (Billa, Mansor, & Mahmud, 2004). In addition, most of the Malaysian watersheds are mainly occupied by forests in the upper stream, while the lower part of the basin is occupied mainly by farmlands for oil palm and rubber plantations. ...
This paper aims to investigate the feasibility offlood management based onthe concept of Integrated Watershed Management (IWM) via a literature review and field surveys. The investigationfocused on the primary industry of oil palm plantations in Malaysia. Although the country is promoting the palm oil industry, the impact of oil palm plantations on the local environment has been relatively disregarded because of the benefits and opportunities, such as subsidies, jobs, and amenities,which the local companies/people can obtain. Effective flood management inoil palm plantations entails the local peoples’ understanding and participation in the management activities, such as removing fallen leaves and weeding an area. Theflood management strategiessuggested inthis research provide new insights into local flood management, which usually focuses on the hydrologic aspects, by promoting the integration of the actual-local environment and local people’s actions for their environment within the framework of IWM.
... In the event where water increase is observed, it is identified suggesting flooding possibility at a certain spot. This is the golden period when flood mitigation plans should be taken by both authorities and the people at the flood-prone location as a precaution before the water rises to a critical level [2]. Most of the systems available were able to detect and report the increase in water to the monitoring station or the appropriate authorities. ...
Flooding is one of the most common disasters in may countries, where it will cause death and loss of property. Today, human activities are the major problem contributing to this disaster such as uncontrolled development, river obstruction, deforestation that damage the catchment area and other factor contributing to flooding. Public use conventional ways to forecast events in many rural areas to track flood occurrence where they will be waiting for some expected activity near the river side. By observing the area that had known in danger, this action is risky. The population always has its own deficiency of society, which will influence the measured data. Thus, a flood protection plan was planned based on human and property. This project idea was generated to solve this issue by developing a Flood Monitoring and Warning System with IoT (FMWSI). This project used Arduino IDE for coding and Blynk software for Internet of Things (IoT) which it can help the user to monitor the road from a long distance. Using ultrasonic sensors, the detection system acts as water level detectors. The i2c 16X2 LCD display and traffic light module were used in this FMWSI to reveals the river's state to the user where it will be located 1km from the selected area so that the citizen will always recognize and be warning. When ultrasonic sensor detects the water level, the led will turn on according to the condition of the water level and the IoT will sends the notification to the user. The device plays an important role in keeping properties and human life safe and monitoring them. This system will help the residence to act before the flood gets worse and prevent flood trap.
... With economic and societal development, higher requirements are being placed on meteorological services, and the demands for more refined services and more accurate forecasts are becoming increasingly urgent. Much work has been performed via many studies (Vasiloff et al. 2007;Fabry and Seed 2009) to improve the accuracy of QPF products, and researchers have previously applied QPF results for flood forecasting and early warning generation (Rezacova and Sokol 2004;Billa et al. 2004;Li et al. 2017). Based on QPF products in combination with the research method presented in this paper, we can simulate waterlogging events and assess the impacts on various industries over forecast horizons of 30 minutes, 1 hour, 2 hours, 3 hours, and 6 hours. ...
As a result of rapid urbanization and climate change, many large- and medium-sized cities in China frequently undergo urban disasters with severe impacts that result in many casualties, induce significant economic losses, and restrict sustainable social and economic development. Providing timely and accurate early warnings is the most effective measure for disaster prevention and mitigation before such disasters can impose severe impacts. In this study, we propose a dynamic impact assessment method for rainstorm waterlogging using land-use data. First, based on a detailed collection of disaster prevention and mitigation data, we construct an impact assessment index based on the assessment objects of this study. Then, a waterlogging simulation is performed, and the simulation results are found to meet the assessment requirements. Finally, we conduct an impact assessment every half hour during a heavy rainfall event and evaluate the performance of the proposed method by assessing the socioeconomic impact, object impact, industry impact, regional impact, and comprehensive impact of the event. These assessments produce valuable information for providing diverse and timely services in the event of urban waterlogging.
... Many variables are used in rainfall-runoff estimations, and using hydrologic models to speculate the frequency of flood incidents adequately is always a challenging task where there is changing land use, land cover, and climate scenarios [12,19,20,21]. Selecting an appropriate CN is necessary for producing consistent results. ...
This study explores the impact of the runoff curve number (CN) on the hydrological model outputs for the Morai watershed, Sindh-Pakistan, using the Soil Conservation Service Curve Number (SCS-CN) method. The SCS-CN method is an empirical technique used to estimate rainfall-runoff volume from precipitation in small watersheds, and CN is an empirically derived parameter used to calculate direct runoff from a rainfall event. CN depends on soil type, its condition, and the land use and land cover (LULC) of an area. Precise knowledge of these factors was not available for the study area, and therefore, a range of values was selected to analyze the sensitivity of the model to the changing CN values. Sensitivity analysis involves a methodological manipulation of model parameters to understand their impacts on model outputs. A range of CN values from 40-90 was selected to determine their effects on model results at the sub-catchment level during the historic flood year of 2010. The model simulated 362 cumecs of peak discharge for CN=90; however, for CN=40, the discharge reduced substantially to 78 cumecs (a 78.46% reduction). Event-based comparison of water volumes for different groups of CN values-90-75, 80-75, 75-70, and 90-40-showed reductions in water availability of 8.88%, 3.39%, 3.82%, and 41.81%, respectively. Although it is known that the higher the CN, the greater the discharge from direct runoff and the less initial losses, the sensitivity analysis quantifies that impact and determines the amount of associated discharges with changing CN values. The results of the case study suggest that CN is one of the most influential parameters in the simulation of direct runoff. Knowledge of accurate runoff is important in both wet (flood management) and dry periods (water availability). A wide range in the resulting water discharges highlights the importance of precise CN selection. Sensitivity analysis is an essential facet of establishing hydrological models in limited data watersheds. The range of CNs demonstrates an enormous quantitative consequence on direct runoff, the exactness of which is necessary for effective water resource planning and management. The method itself is not novel, but the way it is proposed here can justify investments in determining the accurate CN before initiating mega projects involving rainfall-runoff simulations. Even a small error in CN value may lead to serious consequences. In the current study, the sensitivity analysis challenges the strength of the results of a model in the presence of ambiguity regarding CN value.
... Timely and accurate dissemination for early warning information prior to disasters is of great significance for reducing the loss of lives and property. At present, most countries in the world have established early warning system [2] [3] [4] [5], and those systems have played a very important role in the emergen-cy management and response. However, the current early warning system can be further improved in a number of aspects. ...
... Strategic disaster management cycle involves four steps: prepared before disaster, preparation of the arrival, when disaster emergency response and disaster recovery (Tingsanchali, 2012). Disaster management includes the implementation of flood forecasting, early warning, decision-making, experts in preventing catastrophic problems (Billa, Mansor & Mahmud, 2004). Billa, Shattri, Mahmud, and Ghazali (2006) explained that the disaster management strategy has two important stages. ...
Malaysia suffers from many flood disasters in the last decade due to an intense change in the climate regime. Local studies have been conducted over the years to address the flood issues in Malaysia dated back as early as 1990s up to the most recent in 2014. It is important at this stage to point out that there are less traceable documented research in communication during flood disaster, crisis communication during or after a flood disaster, or any relevant analysis of communication activities or processes pre, during and post flood in Malaysia. This study will examine the efficiency of current state of communication management undertaken by the related authorities during the recent flood disaster. It will also evaluate various level of coordination between the public and stakeholders in times of catastrophe. Ultimately this study intends to propose a model for crisis communication framework specific to natural catastrophe management in the Malaysian context. Interviews will be done twofold. Firstly, it will gather information from organizations such as Majlis Keselamatan Negara (MKN), Mercy etc as to what they have experienced and seen in the recent natural catastrophe. Secondly, data will be gathered from the second group of respondents who were affected by the natural catastrophe. The end-product of the analysis of these two groups of data would be the proposed model of Crisis
... Existing studies have tended to focus more towards the development of a disaster management framework (Ahmad, Othman, Zakaria, & Mohd Rodzi, 2014;AlBattat & MatSom, 2014;Baharin, Shibghatullah, & Othman, 2009;Billa, Shattri, Mahmud, & Ghazali, 2006;Jeeva & Puthiyidam, 2014;Mohd Rodzi, Zakaria, Ahmad, & Yahya, 2014) or tools and technology related to flood warnings such as producing and disseminating the warnings using new technologies; radar and communication, the internet, mobile devices, and social networks (Billa, Mansor, & Mahmud, 2004). It has long been understood that it is important to know how technological advances in EWS can be used to more efficiently trigger appropriate reactions of populations to prevent losses from natural hazards (White & Haas, 1975). ...
Early flood warnings are important to allow sufficient time for evacuation. Although warning systems are now in place, key questions remain as to their effectiveness in sending information to the public, which may in part depend on the media used. This paper assesses the effectiveness of warnings disseminated to the public for the December 2014 Kelantan Flood, Malaysia. The flood was the worst in decades making it an appropriate case study with which to assess public awareness and perceptions associated with flood warnings and their dissemination. The effectiveness of warnings issued via different media was assessed by questionnaire. Results show that 56% of respondents received warnings prior to the flood, a majority of them through television and information shared among the public. Whilst the preferred medium of warning is not dependent on age, assessment of peoples’ response to warnings shows that with increasing age responsiveness to orders and readiness to evacuate decreases. To increase the number of people receiving the warnings, Short Message Service (SMS) communications sent from the authorities to a wider audience may be considered, as information shared among the public is observed to be most effective in reaching the greatest number of people.
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... To examine the agricultural risk factors and the policies in place for countering them. To highlight the experiences, challenges, and recommendations resulting from the true disaster event Billa et al. (2004) EMERALD To highlight the spatial information technology in flood disaster management and its application in © 2018, e-ISSN 2680-2491 ...
Flooding occurs periodically in Malaysia and has become a common occurrence. This annual occurrence of floods has given a big impact on lives of humans and other living being. Due to the negative impact of floods, we need to pay serious attention and take alternatives way to reduce this disaster. This paper reviews previous articles relating to flood disaster management in Malaysia based on electronic databases which are subscribed by the university library. The flood disaster management in Malaysia involves four phases, which are prevention/mitigation, preparedness, response and recovery. The disaster prevention/mitigation and preparedness are the best way forward because if these two phases were successfully handled, the burden of the next phases will be reduced. Besides, the agencies responsible for the management of floods in Malaysia have been identified in this study. The usage of technology for managing flood events has also been reviewed. The role of communities affected by the floods is no less important. Their awareness and readiness in facing the flood disaster are indispensable so that the negative impacts resulted from the disasters can be minimised. Therefore, the community should be educated to improve their awareness regarding flood management especially on how and what to prepare for flood as well as how to react during the flood.
... Предмет квантитативног истраживања представља анализа нивоа и фактора утицаја персоналних и срединских фактора на ниво знања ученика о правилном поступању за време природних катастрофа. Имајући у виду геопросторни и временски размештај природних катастрофа на националном и глобалном нивоу (Billa, Mansor, & Mahmud, 2004;Cvetković, 2014;Cvetković & Dragicević, 2014;Cvetković & Stojković, 2015;Dewan, 2013;Guan, Zheng, Zhang, & Qin, 2015;Ivanov & Cvetković, 2016), аутори су се определили да испитају знање ученика о правилном поступању за време одређених геофизичких (земљотрес, цунами, клизишта), климатских (суше и шумски пожари), хидролошких (поплава), биолошких (епидемије) и метеоролошких (олуја) катастрофа. Анкетни упитник је садржао питања о персоналним и срединским факторима и конкретна питања о правилном поступању за време споменутих катастрофа. ...
Bezbednost omladine nakon posledica prirodnih katastrofa direktno je uslovljena njihovim poznavanjem načina postupanja u takvim situacijama. Rukovodeći se time, autori u radu predstavljaju rezultate kvantitativnog istraživanja znanja učenika o pravilnom načinu postupanja za vreme prirodnih katastrofa. Cilj istraživanja predstavlja ispitivanje statistički značajnog uticaja određenih personalnih i sredinskih faktora na nivo znanja učenika o pravilnom načinu postupanja. U realizaciji istraživanja korišćeno je anketno ispitivanje zasnovano na višeetapnom slučajnom uzorkovanju kako bi se obezbedila odgovarajuća reprezentativnost. Ukupno je anketirano oko 3548 učenika iz osamnaest osnovnih i srednjih škola sa područja Beograda. Prema dobijenim rezultatima istraživanja, utvrđeno je da bi 42,9% ispitanika pravilno postupilo za vreme zemljotresa, 77,9% za vreme poplava, 69,2% za vreme klizišta, 92,9% za vreme suše, 90,2% za vreme cunamija, 80,2% za vreme jakih vetrova, 57% za vreme šumskih požara, i 68,8% za vreme epidemija. Pored toga, utvrđeni su različiti uticaji personalnih i sredinskih faktora na pravilnost postupanja za svaku od spomenutih prirodnih katastrofa. Rezultati istraživanja mogu biti iskorišćeni za unapređenje bezbednosti omladine za vreme prirodnih katastrofa.
The safety of youth against the consequences of natural disasters is directly conditioned by their knowledge of the way of acting in such situations. Accordingly, the authors present the results of quantitative research of students’ knowledge of the proper way of acting during natural disasters. The aim of the research is to
examine the statistically significant influence of certain personal
and environmental factors on the level of students’ knowledge of the
proper way of acting. The research included a survey based on multipoint
random sampling in order to ensure adequate representativity.
A total of 3548 students from 18 primary and secondary schools
from Belgrade were interviewed. According to the obtained results
of the survey, 42.9% of the respondents would properly act during earthquakes, 77.9% during floods, 69.2% during landslides, 92.9% during droughts, 90.2% during tsunami, 80.2% during heavy winds,
57% during forest fires, and 68.8% during epidemics. In addition, there are various influences of personal and environmental factors on the properness of acting for each of the mentioned natural disasters. The research results can be used to improve the safety of youth during natural disasters.
... In Malaysia, most floods are caused by river flooding. Such floods can be divided into two types, fast and slow type (Billa et al, 2004). The floods considered slow or taking a longer time are caused by heavy rain or snowmelt continuously produce surface runoff which is very high and exceeds the capacity of a river channel. ...
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... How catastrophic risk influences technology transfer to developing countries has been evaluated in an empirical analysis 107 . It has been found that "natural catastrophic risk is negatively related to the extent of technological transfer taking place between developed and developing countries" 108 . ...
... There is no doubt that precipitation patterns have changed globally in recent. In Malaysia and some Southeast Asian countries, increasing intensities of rainfall during the monsoons are not only a source of major flood but also a triggering cause of major landslide event (Billa et al., 2004). Monsoon flooding in Southeast Asia have impacted many people in terms of loss of lives and property damage. ...
Global warming and climate change is one of the most extensively researched and discussed topical issues affecting the environment. Although there are enough historical evidence to support the theory that climate change is a natural phenomenon, many research scientists are widely in agreement that the increase in temperature in the 20th century is anthropologically related. The associated effects are the variability of rainfall and cyclonic patterns that are being observed globally. In Southeast Asia the link between global warming and the seasonal atmospheric flow during the monsoon seasons shows varying degree of fuzziness. This study investigates the impact of climate change on the seasonality of monsoon Asia and its effect on the variability of monsoon rainfall in Southeast Asia. The comparison of decadal variation of precipitation and temperature anomalies before the 1970s found general increases which were mostly varying. But beyond the 1970s, global precipitation anomalous showed increases that almost corresponded with increases in global temperature anomalies for the same period. There are frequent changes and a shift westward of the Indian summer monsoon. Although precipitation is observed to be 70% below normal levels, in some areas the topography affects the intensity of rainfall. These shifting phenomenon of other monsoon season in the region are impacting on the variability of rainfall and the onset of monsoons in Southeast Asia and is predicted to delay for 15 days the onset of the monsoon in the future. The variability of monsoon rainfall in the SEA region is observed to be decadal and the frequency and intensity of intermittent flooding of some areas during the monsoon season have serious consequences on the human, financial, infrastructure and food security of the region.
Reliable and accurate flood prediction is a challenging task in poorly gauged basins due to data scarcity. Data is an essential component of any AI/ML model today, and the performance of such models hugely depends on the availability of sufficient amount of trusted, representative data. However, unlike a few well-studied rivers, most of the rivers in developing countries are still insufficiently monitored, which significantly hinges the design and development of advanced flood prediction models and early warning systems. This paper presents a multi-modal, sensor-based and near-real time river monitoring system to produce a multi-feature data set for the Kikuletwa river in Northern Tanzania, an area that heavily suffers from frequent floods. Our deployed system, which gather information about river depth levels and weather at several locations, aims at widening the ground truth of the river characteristics and eventually improve the accuracy of flood predictions. We provide details on the monitoring system used to gather the data as well as report on the methodology and the nature of the data. Finally, we present the relevance of the data set in the context of flood prediction, discussing the most suitable AI/ML-based forecasting approaches, while also highlighting some applications of the data set beyond flood warning systems.
The chapter presents some aspects of the seismic risk communication within a systemic disaster management system (SDMS) model. Information and communication technology (ICT) plays a key part in managing natural disasters. An example of seismic risk preparedness for the case of preparatory schools in Mexico City has been used to illustrate this feature of the model. Some conclusions are (1) the model has shown the potentiality to the understanding of the flow of information amongst they key subsystems of the model. It can also be used to any natural hazard management. Regarding the case study, (2) 52% of the participants are not sure whether the key decision makers are concern regarding the level of preparedness of the students for the case of earthquakes; (3) 44.1% of the students considered the best way to learn more on earthquakes was through “civil protection” courses; (d) finally, the actions that the decision makers could take are the implementation of seismic risk courses that should be run by civil protection and to promote the culture of preparedness on seismic risk.
Along the inclining events of flooding events, maintenance towards water infrastructure such as urban small dam is needed. The maintenance needs interdisciplinary approach involving hydrology, hydraulics, water quality, and sediment factors. Due to lack of studies in those fields, the study aims to construct a model by using RESOURCE MODELLING ASSOCIATES program to study behaviours of hydraulics and water quality as small dam management. Numerical modelling, hydrology analysis, hydraulics assessment, water quality tests, and field works are employed in this study, with Agathis small dam as a case. The model could run successfully which the result concludes that the model produces reasonable result with acceptable errors and value of R2. A scenario of constructed wetland is proposed and has good accuracy for future maintenance for hydrology, hydraulics, and environmental management. In addition, the models also could be applied to other problem such as an agricultural field also. In the near future, studies about hydrodynamics and water quality modelling especially sediment on small dams need to be more explored because few studies still have limited information meanwhile they have essential impact towards urban water management.
River-flood forecasting is among the most important feasible non-structural approaches used in reducing economic losses and alleviating human sufferings. In spite of uncertainty in the forecasting of natural disasters, the current prevailing methods developed in many parts of the world in the recent history has made good progress to a great extent. The advancement is attributed mainly due to the availability of high-resolution weather data and the use of sophisticated computer modelling algorithms. However, it is desirable to conduct exploratory review studies to further improving the current state of affairs. The present paper reviews briefly the river-flood forecasting methods currently used worldwide with a specific focus in the context of the Kelantan River in Malaysia. Flooding in Malaysia is recurrent covering a large inhabited area compared with other natural disasters. Some of the popularly used methods in the literature such as statistical methods machine learning and methods based on chaos theory have been reviewed, The paper will also attempt to explore the future direction for research and development that might be useful specifically for dealing with the recurrent rivers flooding in Malaysia. A reasonably acceptable prediction of river streamflow is significantly important in disaster management and water resources management.
The chapter presents some aspects of the seismic risk communication within a systemic disaster management system (SDMS) model. Information and communication technology (ICT) plays a key part in managing natural disasters. An example of seismic risk preparedness for the case of preparatory schools in Mexico City has been used to illustrate this feature of the model. Some conclusions are (1) the model has shown the potentiality to the understanding of the flow of information amongst they key subsystems of the model. It can also be used to any natural hazard management. Regarding the case study, (2) 52% of the participants are not sure whether the key decision makers are concern regarding the level of preparedness of the students for the case of earthquakes; (3) 44.1% of the students considered the best way to learn more on earthquakes was through “civil protection” courses; (d) finally, the actions that the decision makers could take are the implementation of seismic risk courses that should be run by civil protection and to promote the culture of preparedness on seismic risk.
This paper presents some aspects of the ‘communication’ processes within a Systemic Disaster Management System (SDMS) model. Information and communication technology (ICT) plays a key part in managing natural disasters. However, it has been contended that ICT should not be used in ‘isolation’ but it should be seen as ‘part’ of the ‘whole’ system for managing disaster risk. Further research is needed in order to illustrate the full application of the ICT within the context of the developed model.
A rapid growth of agricultural plantations and climatic extremes have raised concerns pertaining to enhanced soil erosion. Soil erosion studies are still relatively limited in Malaysia. In this study, soil erosion in four sites such as high conservation value forests (HCVFs), logged forest (LF), mature oil palm (MOP), and mature rubber (MR) within the Kelantan River Basin was measured. A total of 3,207 measurements were conducted via the Modified Laser Erosion Bridge in all sites over 1 year. Results of soil erosion are 87.63, 25.45, 8.44, and 5.90 t ha−1 yr−1 for the HCVF, LF, MOP and MR, respectively – classified as very severe (HCVF), very high (LF), moderate (MP) and slight (MR) according to the Indian condition classification. Steep slope gradient (significant positive correlation to erosion) and logging are the main factors attributed to the high erosion rates. This is to be further explored in the future and more detailed studies should be conducted on the HCVF and LF areas, respectively. Mitigation measures and sustainable agricultural practices should be planned to control and reduce soil erosion.
This chapter discusses the information system and tools for collecting, storing, and managing damage data in the aftermath of flood events developed within the Poli-RISPOSTA project, a Data model, web portal, and mobile application. Concerning data collection, data at upper levels can be obtained by applying apposite data aggregation rules in order to respond to a specific purpose (e.g., strategic or policy making scope), while data at the local scale need to be often collected by surveys on the field. The Poli-RISPOSTA project addresses some of these issues by creating an ICT system that allows the post-flood damage data management, from data collection to data visualization, described in the chapter. The projects achieved to develop tools that integrate different data formats and support data visualization and spatial analysis, and to use a tablet application for field surveys, which responds to a standardized data collection procedure, called RISPOSTA.
The City of Kota Tinggi in Malaysia was under more than five meters of water during the floods in December 2006 and January 2007. The watershed received between 280 and 530 mm of rain in four days. These extreme events occurred three weeks apart and caused extensive damages. The application of the fully distributed two-dimensional model TREX to simulate these events and the estimation of the return period of such extreme events are the main objectives of this study. The model performance was very good based on the Relative Percentage Different (3.7%), Percent BIAS (overestimated the volume by 1.5%) and Nash-Sutcliffe Efficiency Coefficient (0.8). The TREX model is successful in simulating extreme flood events. The December 2006 rainstorm event at Kota Tinggi is extremely rare and this multi-day rainstorm had an estimated return period greater than 2,000 years. The analysis of return period shows that multi-day rainstorms occur more frequently than single day events. Additionally, we produce a flood threshold graph by integrating both hydrological modelling process using TREX and theoretical formulation of return period. The proposed flood threshold graph is useful in the estimation of the amount of accumulated rainfall from multi-day rainfall that can cause flooding on a large watershed like Kota Tinggi.
Hydrological modeling in Malaysia using two-dimensional fully distributed and physically based model is relatively new. Basic guidelines in choosing model dimensions (i.e., 1D, 1D–2D, 2D, and 3D) are discussed. The application of 3D model will give more accurate results if the groundwater movement is considered but requires more time to simulate and prepare input data. However, the 1D model is less accurate in representing the real topography of the study area, even though requires short time to simulate. This chapter also gives an overview about the hydrological modeling in Malaysia which ranges from 1D to 3D. Several researches on hydrology using different model were reviewed. The success of each model will be highlighted.
This article proposes a development of near-real time rainfall estimation program using Automation Picture Transmission (APT) image received from inexpensive APT reception system with relative humidity and air pressure from the METAR reports. The developed program can be applied to forecast rainfall in the short term for planning, preparing and taking action to timely prevent the disasters by rain. A near-real time rainfall estimate program developed by Python language. A program can estimate the position of rainfall / No rainfall and quantity of rainfall. The position of rainfall / No rainfall estimation model used the gray scale value of APT images obtained from the Advance Very High Resolution Radiometer (AVHRR) channels 2 and 4 with relative humidity and air pressure from the METAR reports at 11 airport stations around of Thailand. The quantity of rainfall model used the relationship between the gray scale value of the APT image from the AVHRR channels 2 and 4 with rainfall value from the rain measurement stations. This equation can expressed as Rain rate = -7.046 + (0.046 * GS 2) + (0.046 * GS 4) - 0.539, the unit in millimeters per 15 minutes (mm./ 15 minutes). When GS 2 and GS 4 are the gray scale values of the APT image from the AVHRR channels 2 and 4, respectively were 0 to 255. The near-real time rainfall estimate program tested with APT images and METAR reports during June to August 2010, found that the position of rainfall / No rainfall estimation error were approximately 10.21% and quantity of rainfall error were approximately ±0.289 mm./15 minutes. The near-real time rainfall estimate program can be applied to the normal rainfall in rainy season. It can not be applied to the rain in monsoon storm and estimation in the daytime only.
Hydrological simulations are useful methods of assessing and testing different scenarios of the impact of a hydrological event on a hydrological environment. Their effect and efficiency are however limited without the support of spatial planning tools such as GIS. GIS provides the platform for simulations to be integrated with supporting basin and floodplain data to be projected spatially and visualized spatially in support of decision making. Kuala Lumpur, Malaysia is experiencing frequent floods due to the rapid expansion of the city and increasing intensity of monsoon rainfall. In this study hydrodynamic simulation is coupled with a well developed digital surface and terrain model (DEM) to map flood extent in Kuala Lumpur. Techniques and methods discuss the integration of hydrological processes, remote sensing and GIS processing in 3D hydrological GIS modeling to represent different flooding scenarios.
Purpose
The frequent occurrence of emergencies and disasters continues to threaten community safety and security. Emergency communications and warning systems (ECWS) allow people to make decisions and take actions before, during and after the emergency or disaster. The critical objective of this study is to determine the critical capacities of ECWS in the Australian context.
Design/methodology/approach
This study used stakeholder analysis in which written submissions from individuals, and public and private organizations collected by the Australian federal government were subjected to structured coding techniques in order to identify major ECWS capacity issues. The summary of findings were generating by axially collapsing and summarizing the coded statements.
Findings
Findings showed that a broad range of ECWS are deployed in the Australian context. These ECWS come with social and/or technical limitations that suggest the importance of adopting an integrated or systems based approach for their construction and deployment. Also, while the identification of critical infrastructure vulnerabilities reinforced the argument for an integrated systems approach for ECWS, this also demonstrated the pressing need to build resilience and redundancy into domestic infrastructure networks. In addition, new and innovative ECWS technologies and solutions will enable improved emergency or disaster management in the future.
Originality/value
This paper simultaneously considers important factors and issues impacting ECWS and provides an instructive discourse on the requirement for more combinative ECWS.
This paper presents some aspects of the 'communication' processes within a Systemic Disaster Management System (SDMS) model. Information and communication technology (ICT) plays a key part in managing natural disasters. However, it has been contended that ICT should not be used in 'isolation' but it should be seen as 'part' of the 'whole' system for managing disaster risk. Further research is needed in order to illustrate the full application of the ICT within the context of the developed model.
This paper presents the method development for the generation of four cloud products based on NOAA/EPS data which is carried out within the context of the EUMETSAT SAF for support of Nowcasting and Very Short Range Forecasting. The development work is focusing on the definition of dynamically changeable multispectral thresholds in order to adapt to variable weather and illumination conditions. In this process, ancillary data and NWP model output will be extensively used. Computation of thresholds will be accomplished by an off-line use of radiative transfer models (6S, RTTOVS and MODTRAN). However, the method for one of the products (the Precipitating clouds product) will contain a mix between physical and statistical retrieval schemes. Some early results from prototyping are shown and the limitations of the methods are discussed. Finally, the potential use of the cloud products in future Nowcasting applications is outlined.
This Letter describes the adjustment of the Convective-Stratiform Technique (CST) to estimate 1991± 93 El NinÄ o rainfall in Ecuador and Peru by means of IR radiation data recorded by the Meteosat-3 VISSR sensor. The adjustment includes (1) a regionalization of a one-dimensional cloud model using local radiosonde data, (2) a ® eld-of-view correction of the VISSR-derived cloud top temperature to model requirements and (3) an adapted discrimination scheme between raining and non-raining clouds. Validation reveals a strong correlation between calculated and observed rainfall for all climatic regimes and rainfall intensities within the study area.
The formation, dynamics and spatial distribution of heavy precipita- tion during the 1991/92 El Nino in Ecuador and northern Peru were examined by means of Meteosat-3 imagery, NOAA-AVHRR-based multichannel sea surface temperatures (MCSST) and additional meteorological observations. The Convective and Stratiform Technique (CST) was used for rain retrieval by means of Meteosat IR data and a cross-correlation approach was applied to Meteosat image sequences to derive cloud motion winds (CMW) which are essential for the analysis of circulation patterns leading to severe precipitation. From an analysis of 45 days with severe precipitation it is proven that three mechanisms were responsible for the formation of heavy rains. Each mechanism reveals a specié c localized impact. (1) The most frequent mechanism (frequency of ~61%) represents an extended land-sea breeze system. During such weather conditions, predominantly locally conéned precipitation patterns occured. Areas aÄ ected by the sea wind front during the day were the coastal plains up to the 1000m contour line on the western Andean slope. Local maxima in the frequency of cloudiness leading to precipitation could be found at isolated peaks of a lower coastal cordillera. At night the highest frequency of precipitation was found over the warm water surface of the Gulf of Guayaquil, mainly due to its coastal shape which signié cantly favours convergence of the nocturnal land breeze. (2) Convection, initiated in the coastal plain and on the western Andean slopes during the afternoon,was signié cantly intensiéed by an entrainment ofremainders of cirrus shields from the Amazon basin. These cloud fragments spilled over the Andes with well-developed trades in the mid/upper troposphere which blew in the opposite direction to the daily sea/up-slope breeze. The spill over points were characterized by areas of deep convection on the western Andean slopes and were frequently valley axes perpendicular to the mountain chain as well as the Andean depression in southern Ecuador. (3) During the main El Nino phase (March- April), heavy and persistent precipitation was extended over wide areas of the coastal plain showing neither a distinct diurnal cycle nor preferential areas. Deep convection was frequently organized in mesoscale convective complexes (MCC) and was spatially correlated with MCSST > 27ß . The extensive instability of the troposphere during these weather conditions was marked by convective cloud streets and an intensiécation of the meridional Hadley circulation oÄ the coast of southern Ecuador and Peru.
Summary The present paper describes two model-coupled approaches for the determination of rain rates from remote sensing data. The idea of both approaches for retrieving precipitation is to account for realistic and actual vertical profiles of temperature and relative humidity, which are taken from meso-scale model data. The original Convective Stratiform Technique (CST) method of Adler and Negri (1988) for estimating precipitation rates from infrared geostationary satellite data was improved with respect to regional adjustments to summertime mid-latitude situations and the use of the water vapour channel of Meteosat to detect mid-latitude convective clouds. In our enhanced CST (ECST) numerical model data (1D cloud model and mesoscale model) are used for a better adjustment to the actual atmospheric situation. The ECST is applied to a case with strong rain events over Germany, and it shows encouraging results in comparison with radar data, particularly for rain area detection. A second issue of the paper is to present a methodology for the improvement of rain retrievals from radar data. A spectral cloud model driven by profiles of a meso-scale model is used to generate actual Z/ R relations for the radar retrieval. Using a high-resolution raingauge network as a validation data set, the first results show an improvement compared to standard Z/ R relations.
The study investigates the use of computer-aided analysis of LANDSAT multispectral data in estimating percentage of imperviousness and associated land uses needed in urban hydrologic modeling. An interactive computer was used to delineate seven land use classifications in the 132-sq mi (342-sq km) Maryland portion of the Anacostia River Basin from LANDSAT data. The land-use distributions compared favorably with those of an earlier study which obtained the same information through analysis of aerial photographs having a scale of 1:4800. The LANDSAT data were used to estimate the basin imperviousness as 25. 1% while the aerial photographic study had given 23. 5%. Comparisons between the photographic and LANDSAT imperviousness estimates are made for subareas within the Anacostia Basin as small as 0. 14 sq mi (0. 36 sq km). Approximately 94 man-days were required to complete the land-use analysis using the aerial photographs while less than 4 man-days were required to accomplish similar tasks using the LANDSAT data.
The convective activity over the Rift Valley lakes of East Africa, as deduced from cloud tops colder than a predefined threshold, is examined. Relationships between satellite-derived convective indices and rainfall measurements are also examined. The diurnal cycle of convective activity over Lake Victoria and over the land is analyzed. The maximum convection is found to occur during the morning between 0500 and 0800 LST over Lake Victoria, and a second maximum occurs in the afternoon. In contrast, over surrounding land, the maximum occurs generally in late afternoon and during the evening. It is also found that a linear relationship exists between satellite-derived convective indices and rainfall measurements; the correlation between the two is strong enough that the indices can be used to estimate annual and areally averaged monthly rainfall. The cold cloud indices explain more than 50% of observed variances of rainfall for the months of May through October. However, the performance is inadequate in several instances during February and March. The results show that the satellite algorithm is robust enough to estimate spatial averages of monthly rainfall with satellite estimates accounting for between 75% and 95% of observed variances of rainfall. The results further show that there is an exceedingly high correlation between convective rainfall over Lake Victoria and in the surrounding catchment. This permitted the derivation of a relationship between rainfall over the lake and its catchment.
A continuously calibrated infrared (IR) geostationary satellite rainfall estimation technique (CCB4) is introduced, in the context of the Nile River Forecast System, an operational system for hydrological modelling and forecasting. The CCB4 incorporates near-real-time rain gauge data to continuously calibrate optimum IR rain/no-rain thresholds and daily rain rates on a daily time step. The ability of the CCB4 and two comparative techniques to estimate daily rainfall at the regional and pixel scales is assessed, using Meteosat IR imagery and gauge data from six wet season months covering three years. The CCB4 shows improved skill in identifying rain days and estimating daily rain amounts at a range of spatial scales, from regional to pixel scales. At the pixel scale, however, improved root mean square errors remain relatively high, ranging between 66% and 84% of the mean unconditional rain rate.
A description is given of the relationship between 6 h averages of fractional coverage of cloud above various height and temperature thresholds, derived from infrared data from the Synchronous Meteorological Satellite 1 (SMS 1), and accumulated rainfall, derived from data obtained with a group of quantitative C-band digital radars. An analysis of the pooled data from all three phases, omitting the single outlier, shows that 75% of the variance in 6 h rainfall accumulations over the GATE B-scale array is explained by a linear function of the fraction of the array covered by cloud higher than 10 km.- from Author
As part of the US Agency for International Development/National Oceanic and Atmospheric Administration project to develop an improved monitoring, forecasting, and simulation system for the river Nile, the Remote Sensing Unit of the University of Bristol has been investigating and developing satellite infrared techniques for small-scale estimation of rainfall over the region of the upper Nile basin. In this paper, the need for variable IR rain/no-rain temperature thresholds as a basis for reliable satellite identification of rain areas over small scales is explained, and the spatially and temporally variable nature of optimum IR rain/no-rain threshold temperatures is examined. -from Authors
The land cover requirements of the Soil Conservation Service (SCS) model used to develop volume of runoff for hydrograph synthesis in suburban areas were modified to be compatible with Landsat digital data. Curve numbers obtained with these alternate land cover categories compared well with those obtained in published example problems using conventional categories. -from ASCE Publications Abstracts
An attempt to estimate rainfall in convectively active regions using Kuo's parameterization scheme has been made. The precipitation in this model is given by P = lQ1/t, where P is the precipitation per unit time, l the fraction of a synoptic area covered by deep active convection, Q1 the mount of condensation heating according to moist adiabatic ascent, and t a time parameter related to the precipitating lifetime of the convective elements.Investigation of the above equation when P, l and Q1 were available indicated that an appropriate time parameter was 30 min and that the main contribution to the precipitation comes from the l parameter.A case is presented where l is obtained from satellite observations. The resulting precipitation estimate appears quite reasonable. The potential for estimating precipitation over the tropical means is pointed out.
The development of a satellite infrared technique for estimating convective and stratiform rainfall area and volume and its application in studying the diurnal variability of rainfall in Amazonia are presented. Cloud systems are defined in the technique by the 253 K infrared (IR) temperature isotherm. The convective and stratiform rain areas within these cloud systems are then related to morphologic characteristics of the IR temperature fields. Rainfall rates are assigned to the defined convective and stratiform areas using IR- microwave-derived rain rate probability matching relationships. The training data set consists of three months of collocated IR observations and microwave (MW) rain rate retrievals over a region in the Amazon Basin. Evaluation of instantaneous rain rate estimates over a second independent region in the Amazon showed 25% (−40%) systematic error and 55% (70%) residual random error standard deviation in morning (evening) MW overpasses. The method is used to derive the mean diurnal cycle of rainfall and investigate the relative contribution from its convective and stratiform components. Finally, the technique is applied to study the time evolution of rainfall and the transition from convective to stratiform over selected sites in the Amazon.
The global distribution of area-averaged precipitation is extremely difficult to determine with precision. In this paper we will explain why satellite measurements are necessary for the production of global analyses of precipitation, summarize some of the various methods which have been used to estimate rainfall from satellite observations over the past two decades, and describe an attempt to use a mix of remotely sensed estimates and surface observations of rainfall to produce analyses of the large-scale rainfall for the globe. We will discuss the relationship between two types of satellite-derived precipitation estimates over the oceans from 40°N to 40°S, and then will conclude with a discussion of some possible physical mechanisms which might be responsible for the observed correlation between area-averaged rainfall and cloudiness.
A brief introduction to MIKE11 and its capabilities
- Danish Hydrological Institute
Magnitude and frequency of flood in peninsular Malaysia
- Department of Irrigation and Drainage
Calibration and evaluation of modified tank model (flood forecasting model) for Kelantan river basin
- K H Ho
- A H Ghazali
- S F Chong
Flood forecasting and warning systems in Malaysia”, Hydrology and Water Resources Division, Department of Irrigation and Drainage
- B A Keizrul
- S F Chong
Remote sensing and GIS: potential application for flood hazard forecasting
- L Lanza
- M Conti
Automated modeling of flash floods in Mediterranean areas: the September 1992 events over the Liguria region
- L Lanza
- M Conti
- La Barbera
Regional flood frequency analysis: revision and development of expert system for peninsular Malaysia
- T Wardah
- I Zaidah
High resolution cloud product from NOAA AVHRR and AMSU”, Swedish Meteorological and Hydrological Institute (SMHI)
- K Karlsson
- A Thoss
- A Dybbroe