scholarly journals Stochastic Modeling of Rainfall Series in Kelantan Using an Advanced Weather Generator

2018 ◽  
Vol 8 (1) ◽  
pp. 2537-2541
Author(s):  
A. H. Syafrina ◽  
A. Norzaida ◽  
O. Noor Shazwani
Keyword(s):  
Extreme Values ◽  
Probability Distributions ◽  
Meteorological Data ◽  
Extreme Rainfall ◽  
Peninsular Malaysia ◽  
Weather Generator ◽  
Rainfall Series ◽  
Weather Data ◽  
Extreme Rainfall Events ◽  
North East

Weather generator is a numerical tool that uses existing meteorological records to generate series of synthetic weather data. The AWE-GEN (Advanced Weather Generator) model has been successful in producing a broad range of temporal scale weather variables, ranging from the high-frequency hourly values to the low-frequency inter-annual variability. In Malaysia, AWE-GEN has produced reliable projections of extreme rainfall events for some parts of Peninsular Malaysia. This study focuses on the use of AWE-GEN model to assess rainfall distribution in Kelantan. Kelantan is situated on the north east of the Peninsular, a region which is highly susceptible to flood. Embedded within the AWE-GEN model is the Neyman Scott process which employs parameters to represent physical rainfall characteristics. The use of correct probability distributions to represent the parameters is imperative to allow reliable results to be produced. This study compares the performance of two probability distributions, Weibull and Gamma to represent rainfall intensity and the better distribution found was used subsequently to simulate hourly scaled rainfall series. Thirty years of hourly scaled meteorological data from two stations in Kelantan were used in model construction. Results indicate that both probability distributions are capable of replicating the rainfall series at both stations very well, however numerical evaluations suggested that Gamma performs better. Despite Gamma not being a heavy tailed distribution, it is able to replicate the key characteristics of rainfall series and particularly extreme values. The overall simulation results showed that the AWE-GEN model is capable of generating tropical rainfall series which could be beneficial in flood preparedness studies in areas vulnerable to flood.

100 years of Belgian rainfall: are there trends?

2002 ◽  
Vol 45 (2) ◽  
pp. 55-61 ◽  
Author(s):  
G. Vaes ◽  
P. Willems ◽  
J. Berlamont
Keyword(s):  
Extreme Rainfall ◽  
Rainfall Series ◽  
Strong Increase ◽  
Final Conclusion ◽  
Small Decrease ◽  
Extreme Rainfall Events ◽  
Rainfall Events ◽  
Flooding Frequency ◽  
Small Aggregation ◽  
Aggregation Level

In 1999 the digitisation of old rainfall records of measurements at Uccle (Belgium) was completed, which resulted in a unique rainfall series of 100 years (period 1898-1997). This is an ideal opportunity to search for trends in the rainfall over the last century. Large variations in rainfall probability over the century have been observed. For small aggregation levels there is a small decrease in extreme rainfall events over the century. For large aggregation levels there is a more explicit increase in extreme rainfall. Because the rainfall on seasonal aggregation level is only slightly increased, the increase in extreme rainfall events for aggregation levels between a few days and a few months can only occur due to larger clustering. However, the final conclusion is that no significant trend can be observed. A pure random variation of the rainfall can cause equally large variations. This does not exclude a possible trend in flooding frequency, due to the strong increase in urbanisation over the last century.

scholarly journals Spatial and temporal variability studies of precipitation considering the future climate scenarios, with emphasis on extreme events

2019 ◽  
Author(s):  
Luiza Marchezan Bezerra ◽  
Ana Maria Heuminski de Avila ◽  
Vânia Rosa Pereira
Keyword(s):  
Global Climate ◽  
Meteorological Data ◽  
Extreme Rainfall ◽  
Future Climate ◽  
Extreme Weather Events ◽  
Spatial And Temporal Variability ◽  
Climate Scenarios ◽  
Natural Ecosystems ◽  
Intergovernmental Panel ◽  
Extreme Rainfall Events

The Intergovernmental Panel on Climate Change (IPCC) affirms that in future climate scenarios, the frequency and intensity of extreme weather events may intensify as a result of changes in the global climate, causing negative impacts on the population and natural ecosystems. Therefore, the impacts caused by these events will require adaptations which, in turn, will be based on future projections carried out through simulations of various global and regional models. Thus, this scientific initiation project had the objective of studying the frequency and spatial variability of extreme rainfall events in the city of Campinas, through simulations carried out using the regional model ETA-HADGEM2-ES and surface meteorological data, considering present and future scenarios.

scholarly journals Extreme precipitation events in the Forest Promotion Complex of Silesian Beskid

2015 ◽  
Vol 57 (1) ◽  
pp. 18-27
Author(s):  
Grzegorz B. Durło ◽  
Stanisław Małek ◽  
Jarosław Socha
Keyword(s):  
Water Management ◽  
Natural Environment ◽  
Negative Impact ◽  
Meteorological Data ◽  
Extreme Rainfall ◽  
Extreme Rainfall Events ◽  
Ecological Requirements ◽  
Extreme Precipitation Events ◽  
Spruce Stands ◽  
Subalpine Region

Abstract An increase in frequency of weather phenomena in the Western Beskids that are disadvantageous for natural environment caused an upset of ecologic balance, especially within the scope of water management and retention. Concerns referring to forest groups maintaining their stability are fully justified, regarding that in many areas of the Beskids, there is an intensive reconstruction of stands of trees in the lower subalpine region. In turn, young generations of trees are continuously stresses, which arise from periodic shortages of precipitation within the course of the whole vegetation process. The presented work encompasses characteristics of extreme rainfall events that might have a negative impact on growth and development of Norway spruce stands in the Silesian Beskid in recent decades. The article makes use of meteorological data from a multiannual period (1951–2010), gathered in 26 meteorological stations of the Polish Institute of Meteorology and Water Management (IMGW) in Silesian Beskid one station located in the Carpathian regional gene bank and two under canopy posts located in Wisła forestry inspectorate area. Special attention was devoted to the presence of extreme phenomena and their repeatability. The analysis of parameters of rainfall sequences was complemented with indexes determining ecological requirements of spruce, such as: Schmuck moisture indicator, Vogel-Daniels habitat dryness index and abundance of rainfall indicator developed in this study. Results of climatological analysis confirmed that weather phenomena with, especially dynamic course may lead to destabilisation of even a properly formed and adequately developed forest ecosystem, and as a consequence, disturb stability in the natural environment. Diminishment of the index of precipitation size, which has been observed in recent years, may be one of the most crucial causes that limit the number of spruces in the stands of trees of the lower subalpine region in Silesian Beskid. The climatological analysis confirmed that during 60 years in Silesian Beskid, there were over 20 extreme weather (precipitation) episodes of different courses, intensity and surface reach, out of which at least 9 played a key role in lowering the health condition of the trees, as a consequence, it influenced destabilisation of the spruce stands in the lower subalpine region, regardless of their age or location within the area.

Recent changes in extreme rainfall events in Peninsular Malaysia: 1971–2005

2009 ◽  
Vol 99 (3-4) ◽  
pp. 303-314 ◽  
Author(s):  
Wan Zawiah Wan Zin ◽  
Suhaila Jamaludin ◽  
Sayang Mohd Deni ◽  
Abdul Aziz Jemain
Keyword(s):  
Extreme Rainfall ◽  
Peninsular Malaysia ◽  
Extreme Rainfall Events ◽  
Rainfall Events

ANALYSIS OF EXTREME RAINFALL INDICES IN PENINSULAR MALAYSIA

2016 ◽  
Vol 78 (9-4) ◽  
Author(s):  
Nur Shazwani Muhammad ◽  
Amieroul Iefwat Akashah ◽  
Jazuri Abdullah
Keyword(s):  
East Coast ◽  
Daily Rainfall ◽  
Extreme Rainfall ◽  
Peninsular Malaysia ◽  
Rainfall Data ◽  
Extreme Rainfall Events ◽  
Rainfall Events ◽  
Daily Rainfall Data ◽  
Extreme Rain ◽  
Increasing Trends

Extreme rainfall events are the main cause of flooding. This study aimed to examine seven extreme rainfall indices, i.e. extreme rain sum (XRS), very wet day intensity (I95), extremely wet day intensity (I99), very wet day proportion (R95), extremely wet day proportion (R99), very wet days (N95) and extremely wet days (N99) using Mann-Kendall (MK) and the normalized statistic Z tests. The analyses are based on the daily rainfall data gathered from Bayan Lepas, Subang, Senai, Kuantan and Kota Bharu. The east coast states received more rainfall than any other parts in Peninsular Malaysia. Kota Bharu station recorded the highest XRS, i.e. 648 mm. The analyses also indicate that the stations in the eastern part of Peninsular Malaysia experienced higher XRS, I95, I99, R95 and R99 as compared to the stations located in the western and northern part of Peninsular Malaysia. Subang and Senai show the highest number of days for wet and very wet (N95) as compared to other stations. Other than that, all stations except for Kota Bharu show increasing trends for most of the extreme rainfall indices. Upward trends indicate that the extreme rainfall events were becoming more severe over the period of 1960 to 2014. 

ANALYSIS OF TRENDS OF EXTREME RAINFALL EVENTS USING MANN KENDALL TEST: A CASE STUDY IN PAHANG AND KELANTAN RIVER BASINS

2016 ◽  
Vol 78 (9-4) ◽  
Author(s):  
Mazlina Alang Othman ◽  
Nor Azazi Zakaria ◽  
Aminuddin Ab. Ghani ◽  
Chun Kiat Chang ◽  
Ngai Weng Chan
Keyword(s):  
Climate Change ◽  
River Basin ◽  
Extreme Event ◽  
Extreme Rainfall ◽  
River Basins ◽  
Peninsular Malaysia ◽  
Extreme Rainfall Events ◽  
Rainfall Events ◽  
Mk Test ◽  
Kelantan River Basin

Climate change leads to changes in rainfall and extreme event. This phenomenon has already begun to transform the rainfall patterns in Malaysia. It was clearly proven when the northern and eastern states of Peninsular Malaysia such as Kelantan, Terengganu, Pahang, Perak and Johor were hit by the catastrophic floods in December 2014, events that have been described as the worst in decades. Although there are a number of studies in climate change and extreme rainfall events in Malaysia, there are still large knowledge gaps about their relationship. Understanding the shifts and predicting changing trends in rainfall distribution is needed for predicting and managing the floods.  In this paper, Mann Kendall (MK) test and Sen's Slope estimator are employed to determine the trend of extreme rainfall events of various storm durations in the Pahang and Kelantan river basins. The results indicate that annual maximum daily rainfall for Pahang River basin and Kelantan River basin increased throughout 45 years. Results show that the percentage of stations with statistically significant trend (at 0.05 significance level) in the Kelantan River basin are higher compared to the Pahang River basin. Percentage of stations showing increasing trends were much higher for short duration rainfall (10, 30 and 60 minutes and  3 hours) compared to long duration rainfall (6, 12, 24, 48, 120 and 240 hours). This study will be useful for planning, designing and managing floods and stormwater systems in this area

scholarly journals Selection of Hydrological Probability Distributions for Extreme Rainfall Events in the Regions of Colombia

Water ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1397 ◽  
Author(s):  
Óscar E. Coronado-Hernández ◽  
Ernesto Merlano-Sabalza ◽  
Zaid Díaz-Vergara ◽  
Jairo R. Coronado-Hernández
Keyword(s):  
Frequency Analysis ◽  
Probability Distributions ◽  
Extreme Rainfall ◽  
Return Periods ◽  
Extreme Rainfall Events ◽  
Maximum Rainfall ◽  
Rainfall Events ◽  
Moments Method ◽  
Engineering Projects ◽  
Selection Of

Frequency analysis of extreme events is used to estimate the maximum rainfall associated with different return periods and is used in planning hydraulic structures. When carrying out this type of analysis in engineering projects, the hydrological distributions that best fit the trend of maximum 24 h rainfall data are unknown. This study collected maximum 24 h rainfall records from 362 stations distributed throughout Colombia, with the goal of guiding hydraulic planners by suggesting the probability distributions they should use before beginning their analysis. The generalized extreme value (GEV) probability distribution, using the weighted moments method, presented the best fits of frequency analysis of maximum daily precipitation for various return periods for selected rainfall stations in Colombia.

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