scholarly journals Analisis Karakteristik Hujan Ekstrim Untuk Mendukung Pengembangan Peringatan Dini Lahar Dingin di Lereng Gunung Merapi

2020 ◽  
pp. 35-40
Author(s):  
S.Y. Iryani
Keyword(s):  
Relative Frequency ◽  
Rainfall Intensity ◽  
Critical Line ◽  
Negative Impact ◽  
Warning System ◽  
Extreme Rainfall ◽  
Public Infrastructure ◽  
Rainfall Characteristics ◽  
Rainfall Analysis ◽  
Hourly Rainfall

Mt. Merapi cold lava disasters in 2010 had caused a lot of public infrastructure and facilities in the area around Mt. Merapi were damaged, due to the occurrence of debris flows triggered by extreme rainfall. Analysis of extreme rainfall characteristics are conducted to determine the pattern of distribution of the amount of hourly rainfall  in the slopes of Mt. Merapi. To reduce the negative impact caused by cold lava flood, it is necessary to plan an Early Warning System (EWS) and the proper evacuation measures. EWS based Rainfall intensity, can refer to the Critical Line Curve. The research  results showed the greatest rainfall intensity occurred in the Mt. Maron station Pwith the cumulative relative frequency of rainfall intensity >20 mm/hr in between the years 1988 to 2010 with 6.74%. Analysis of the incidence of the most extreme hourly rainfall of 14 rainfall stations in the slopes of Mt. Merapi in 1988 to 2010 occurred in kemasan station in 2010 with 621.5 mm in January at 6:00 p.m. to 7:00 p.m. Critical Line Curve Kali Gendol rain station Batur, Deles and Sorosan, non-causing rainfall in the dangerous area is 24 events (13.79%), causing rainfall in the dangerous area is 4 events (2.30%) and non-causing rainfall in the safety area is 146 events (83.91%). Cumulative Relative frequency rainfall intensity >20 mm/hr at rainfall stations close to the Kali Gendol i.e. Batur, Deles and Sorosan rainfall station from the highest to the lowest are   2.74%, 2.33% and 1.70%, respectively.

scholarly journals Relationship between Surface Temperature and Extreme Rainfalls: A Multi-Time-Scale and Event-Based Analysis*

2014 ◽  
Vol 15 (5) ◽  
pp. 1999-2011 ◽  
Author(s):  
Gérémy Panthou ◽  
Alain Mailhot ◽  
Edward Laurence ◽  
Guillaume Talbot
Keyword(s):  
Relative Humidity ◽  
Rainfall Intensity ◽  
Daily Rainfall ◽  
Extreme Rainfall ◽  
Limiting Factor ◽  
Coastal Regions ◽  
Dewpoint Temperature ◽  
Hourly Rainfall ◽  
Event Based ◽  
The Relationship

Abstract Recent studies have examined the relationship between the intensity of extreme rainfall and temperature. Two main reasons justify this interest. First, the moisture-holding capacity of the atmosphere is governed by the Clausius–Clapeyron (CC) equation. Second, the temperature dependence of extreme-intensity rainfalls should follow a similar relationship assuming relative humidity remains constant and extreme rainfalls are driven by the actual water content of the atmosphere. The relationship between extreme rainfall intensity and air temperature (Pextr–Ta) was assessed by analyzing maximum daily rainfall intensities for durations ranging from 5 min to 12 h for more than 100 meteorological stations across Canada. Different factors that could influence this relationship have been analyzed. It appears that the duration and the climatic region have a strong influence on this relationship. For short durations, the Pextr–Ta relationship is close to the CC scaling for coastal regions while a super-CC scaling followed by an upper limit is observed for inland regions. As the duration increases, the slope of the relationship Pextr–Ta decreases for all regions. The shape of the Pextr–Ta curve is not sensitive to the percentile or season. Complementary analyses have been carried out to understand the departures from the expected Clausius–Clapeyron scaling. The relationship between dewpoint temperature and extreme rainfall intensity shows that the relative humidity is a limiting factor for inland regions, but not for coastal regions. Using hourly rainfall series, an event-based analysis is proposed in order to understand other deviations (super-CC, sub-CC, and monotonic decrease). The analyses suggest that the observed scaling is primarily due to the rainfall event dynamic.

scholarly journals Effect of Extreme Rainfall Intensity on Matric Suction and Ground Movement

2020 ◽  
Vol 195 ◽  
pp. 01022 ◽  
Author(s):  
Muhammad Hazwan Zaki ◽  
Mastura Azmi ◽  
Siti Aimi Nadia Mohd Yusoff ◽  
Muhd Harris Ramli ◽  
Mohd Azril Hezmi
Keyword(s):  
Rainfall Intensity ◽  
Extreme Rainfall ◽  
Matric Suction ◽  
Ground Movement ◽  
Laboratory Studies ◽  
Mass Wasting ◽  
Significant Drop ◽  
Rainfall Events ◽  
Hourly Rainfall ◽  
Rain Simulator

Increased intensity of rainfall events due to extreme climate change has led to the substantial increase in the occurrence of disasters, especially in a tropical-climate country such as Malaysia. Rainfall-induced landslide has become one of the most common types of disasters, and its triggering factors are still uncertain and impossible to predict. In this study, the effect of extreme rainfall intensity on groundwater behaviour is addressed through laboratory-scale testing. The adopted rainfall intensity is 60 mm/h, which was the heaviest hourly rainfall intensity recorded in Sarawak on 3rd January 2016 and 80 mm/h, which was the corresponding value recorded in Penang on 10th October 2016. The simulation is conducted on four cases. The simulated rainfall exhibits a duration of 6 h. In addition, the overall trend of the matric suction measurement and soil moisture in all cases is discussed on the basis of the results obtained from laboratory studies. After the rain simulator stopped, the matric suction decreases, and it remains stagnant, followed by a significant drop in the reading. For all cases, failure occurs, albeit at different times with different volumes of mass wasting.

scholarly journals A Study on the Rainfall and Landslides Along Sarawak Road Using the Antecedent Rainfall Analysis

2011 ◽  
Vol 2 (1) ◽  
pp. 1-6
Author(s):  
Tay J. E. ◽  
Selaman O. S.
Keyword(s):  
Rainfall Intensity ◽  
Clayey Soil ◽  
Warning System ◽  
Civil Defense ◽  
The State ◽  
Repair Cost ◽  
Antecedent Rainfall ◽  
Rainfall Analysis ◽  
Landslide Occurrence

Sarawak is a state known for its high percentage of clayey soil which is overlaid with "weak" strata. The state has experienced many cases of severe landslides which even resulted to deaths. This study aims to address the correlation between rainfall intensity and landslide occurrences along roads in Sarawak. By using the antecedent rainfall analysis, this study emphasizes on more than 50 cases of landslides which occurred along Sarawak roads in the early 2009. Where, during the month of January marks the most amount of rainfall experienced by the state in that year. Many landslide cases were reported, especially along the stretch of Sarawak roads, leading to injuries and road repair cost. The hyetograph drawn in this analysis provides probability of days of antecedent rainfall that induces landslides as well as the total amount of rainfall during the antecedent period that would lead to landslide occurrence. The intensity of rainfall on the day of landslides itself as well as the highest intensity of rainfall during the antecedent period is also analyzed to establish whether it is a factor leading to the landslide occurrence. The observations and forecasts present in this paper will provide warning system for the members of public as well as the state's civil defense authority before the occurrence of rainfall-induced landslide.

scholarly journals Rainfall Monitoring to Support Temporal and Spatial Information of Debris Flow Initiation in Merapi Volcano

2021 ◽  
Vol 13 (3) ◽  
Author(s):  
Ani Hairani ◽  
◽  
Adam Pamudji Rahardjo ◽  
Djoko Legono ◽  
Istiarto Istiarto ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Debris Flow ◽  
Rainfall Intensity ◽  
Spatial Information ◽  
Line Graph ◽  
Warning System ◽  
Surface Flow ◽  
Merapi Volcano ◽  
Hourly Rainfall ◽  
Debris Flow Initiation

Debris flow frequently attacks rivers on slopes of Merapi Volcano and causes fatalities and damage of infrastructures. To reduce the risk of debris flow, a warning system has been developed by Sabo Office Center. Critical line and snake line graph are applied in Merapi Volcano to monitor characteristics of rainfall in the upland river basin. However, this warning system cannot predict the arrival time and location of the debris flow occurrence. Numerical simulation seems to be a good tool to improve its performance. This research proposed an idea to combine rainfall-based warning system with the numerical simulation model. This model used slope stability theory to identify debris flow initiation. Results of this research showed that fluctuation of rainfall intensity reflects changes of debris flow initiation area. The more severe rainfall intensity, the larger volume of surface flow, and thus the greater debris flow initiation takes place. When the rainfall monitoring is combined with the debris flow simulation results, there is a tendency of the enlargement of the debris flow area to follow the growth of the hourly rainfall.

scholarly journals The role of cyclonic activity in tropical temperature-rainfall scaling

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Dominik Traxl ◽  
Niklas Boers ◽  
Aljoscha Rheinwalt ◽  
Bodo Bookhagen
Keyword(s):  
Global Warming ◽  
Rainfall Intensity ◽  
Surface Air Temperature ◽  
Extreme Rainfall ◽  
Intensity Increase ◽  
Cyclonic Activity ◽  
Near Surface ◽  
Hourly Temperature ◽  
Hourly Rainfall ◽  
Rainfall Extremes

AbstractThe attribution of changing intensity of rainfall extremes to global warming is a key challenge of climate research. From a thermodynamic perspective, via the Clausius-Clapeyron relationship, rainfall events are expected to become stronger due to the increased water-holding capacity of a warmer atmosphere. Here, we employ global, 1-hourly temperature and 3-hourly rainfall data to investigate the scaling between temperature and extreme rainfall. Although the Clausius-Clapeyron scaling of +7% rainfall intensity increase per degree warming roughly holds on a global average, we find very heterogeneous spatial patterns. Over tropical oceans, we reveal areas with consistently strong negative scaling (below −40%∘C−1). We show that the negative scaling is due to a robust linear correlation between pre-rainfall cooling of near-surface air temperature and extreme rainfall intensity. We explain this correlation by atmospheric and oceanic dynamics associated with cyclonic activity. Our results emphasize that thermodynamic arguments alone are not enough to attribute changing rainfall extremes to global warming. Circulation dynamics must also be thoroughly considered.

scholarly journals DEVELOPMENT OF WARNING CRITERIA FOR LAHAR FLOW DISASTER IN GENDOL RIVER AREA OF MOUNT MERAPI

2015 ◽  
Vol 1 (1) ◽  
Author(s):  
Ernowo Ary Fibriyantoro
Keyword(s):  
Early Warning System ◽  
Rainfall Intensity ◽  
Critical Line ◽  
Warning System ◽  
Rainfall Data ◽  
Infrastructure Development ◽  
Simple Method ◽  
Warning Criteria ◽  
The Impact ◽  
Existing Data

The eruption of Mount Merapi in 2010 leads to the lahar flow disaster in the region of the mountain slopes. Due to the impact caused by the lahar flow, it is important to develop warning criteria for lahar flow disaster with a simple method corresponding to the limitation of existing data and parameters. One of the methods is by analyzing rainfall data to predict the occurrence of lahar flow in Gendol River. It applies the setting of standard rainfall for warning and evacuation of sediment disasters based on Guidelines for the Development of Warning and Evacuation System against Sediment Disasters in Developing Countries, published by the Ministry of Land, Infrastructure, and Transport (MLIT) Infrastructure Development Institute - Japan, 2004. This study analyzed the critical line (CL) which can be used to predict the occurrence of lahar flow based on the rain characteristics namely working rainfall and rainfall intensity. Furthermore, it can be established by warning line (WL) and the evacuation line (EL) as a basis for determining the standard rainfall for warning (R1) and standard rainfall for evacuation (R2). The value of R1 obtained ± 6 mm and R2 ± 29 mm. The value of R1 and R2 are strongly influenced by the availability of rainfall data and occurrence of lahar flow. The results of this research were expected to be used as input for the warning criteria development of early warning system lahar flow disaster on the slopes of Mount Merapi, particularly in the area of Gendol River.

Predicting extreme precipitation effects on the geomorphology of small mountain catchments, northern Apennines (Italy)

2021 ◽  
Author(s):  
stefano segadelli ◽  
federico grazzini
Keyword(s):  
Rainfall Intensity ◽  
Practical Interest ◽  
Extreme Rainfall ◽  
Northern Apennines ◽  
Convective System ◽  
Time Interval ◽  
Stream Channels ◽  
Extreme Rainfall Events ◽  
Rainfall Events ◽  
Hourly Rainfall

<p>Meteorological events characterized by extreme rainfall intensity have recently struck the hilly and mountainous territory of the northern Apennines (Italy) as well as many other geographic areas of the world. These extreme rainfall events trigger fast flows of debris along the slopes, stream channels, landslides, and floods, which damage many man-made structures such as roads, houses, water-pipes, etc. There is thus a strong practical interest in predicting the frequency and intensity of these effects for emergency management and to reduce the vulnerability of the territory.</p><p>In 2015 an intense rainfall event hit the Valleys of the Trebbia, Nure, and Aveto watercourses in the emilian-ligurian Apennines. In about 6 h a mesoscale convective system deployed a stunning amount of precipitation of 340 mm, with an extreme hourly rainfall intensity of >100 mm/h. During this event, several types of widespread effects on the ground developed i.e., fast flows of debris along the slopes and stream channels (a total number of 305 occurrences), shallow landslides (342) and overbank flooding occurred. Instrumental as well as geological and historical data clearly suggest that extreme rainfall events are increasing in the northern Apennines, in good agreement with the international literature. Through the optimal combination of rainfall data and radar volumes, in this work we present a detailed rainfall analysis, which will serve as a basis to create a quantitative correlation with debris flows over elementary hydrological units. The meteorological analysis of the storm led us to consider the 3 h accumulation rain field as the most relevant for flood triggering. This time interval is short enough to describe the intensity peak of macro precipitating structures, and at the same time it is long enough to allow the development of the debris and stream-flow processes described. The very good match between the 3 h peak intensity and the distribution of high-discharge and hillslope-debris flow support the hypothesis. The 3 h interval further emphasizes the meteorological event with respect to its overall duration of 6 h.</p><p>We aim at providing an objective basis for future predictions, starting from the recognition of the forcing meteorological events, allowed us to clearly identify high-intensity-precipitation thresholds triggering flood in small mountain catchments.</p><p><strong>Keywords: </strong>floods; catchment; threshold; extreme rainfall events; northern Apennines</p>

Specific features of estimating calculated rainfall rates with account of extreme rain showers

2021 ◽  
pp. 50-55
Author(s):  
С.Н. Волков ◽  
А.И. Житенев ◽  
О.Н. Рублевская ◽  
Ю.А. Курганов ◽  
И.Г. Костенко ◽  
...  
Keyword(s):  
Rainfall Intensity ◽  
Experimental Studies ◽  
Measurement Data ◽  
Extreme Rainfall ◽  
Experimental Information ◽  
Wastewater Disposal ◽  
Rain Gauges ◽  
Experimental Base ◽  
Extreme Rain ◽  
Official Data

Анализ официальных источников информации показывает, что распределение экстремальных дождей по территории происходит с учетом микроклиматических особенностей ее местности. Для оценки степени достоверности таких закономерностей в пределах мегаполисов проведены экспериментальные исследования, в которых в качестве экспериментальной базы принята система водоотведения Санкт-Петербурга, в качестве средств измерения – сеть из 34 автоматических осадкомеров, осуществляющих записи с интервалом 5 минут, в качестве экспериментальной информации – база данных результатов измерений в течение шести лет. В результате исследований установлено, что в городской среде формируется микроклимат, отличающийся от климата за ее пределами. Кроме того, в масштабах мегаполисов имеются микроклиматические зоны, в которых зависимости интенсивностей осадков от их повторяемости могут существенно отличаться. При этом отличия начинают проявляться при периодах р однократного превышения расчетной интенсивности дождей от 1,5–2 лет, а при их меньших значениях отличия не выявлены. Полученный результат согласуется с данными исследований других авторов, экспериментально установивших, что количество экстремальных дождей увеличивается в тех районах мегаполисов, как правило, исторических,в которых меньше зеленых насаждений и, соответственно, более высокая степень перегрева поверхности в летнее время. The analysis of official data resources shows that the distribution of extreme rainfall over the territory is carried out with account of the microclimatic features of the area. To estimate the degree of reliability of such patterns within megalopolises, experimental studies were carried out, where the wastewater disposal system of St. Petersburg was assumed as an experimental base; a network of 34 automatic rain gauges recording with an interval of 5 minutes was assumed as a measuring instrument, and a base was used as experimental information, i. e., a measurement data base for six years. As a result of the research, it has been established that a microclimate is formed in the urban environment that differs from the climate outside it. Besides, on a megacity scale, there are microclimatic zones where the dependences of precipitation intensities on their frequency can differ significantly. In this case, the differences begin to manifest at periods p of one-time excess of the calculated rainfall intensity from 1.5–2 years, whereas at lower values, no differences have been found. The result obtained is consistent with the research data obtained by other authors, who experimentally established that the amount of extreme rainfall increased in those areas of megacities, as a rule, historical ones, where fewer green spaces are located, and, accordingly, a higher degree of surface overheating in summer is recorded.

scholarly journals Determination of rainfall thresholds for shallow landslides by a probabilistic and empirical method

2015 ◽  
Vol 3 (5) ◽  
pp. 3487-3508
Author(s):  
J. Huang ◽  
N. P. Ju ◽  
Y. J. Liao ◽  
D. D. Liu
Keyword(s):  
Early Warning ◽  
Regional Scale ◽  
Warning System ◽  
Rainfall Threshold ◽  
Empirical Method ◽  
Shallow Landslides ◽  
Data Sets ◽  
Threshold Values ◽  
Mountainous Regions ◽  
Hourly Rainfall

Abstract. Rainfall-induced landslides not only cause property loss, but also kill and injure large numbers of people every year in mountainous areas in China. These losses and casualties may be avoided to some extent with rainfall threshold values used in an early warning system at a regional scale for the occurrence of landslides. However, the limited availability of data always causes difficulties. In this paper we present a method to calculate rainfall threshold values with limited data sets for the two rainfall parameters: maximum hourly rainfall intensity and accumulated precipitation. The method has been applied to the Huangshan region, in Anhui Province, China. Four early warning levels (Zero, Outlook, Attention, and Warning) have been adopted and the corresponding rainfall threshold values have been defined by probability lines. A validation procedure showed that this method can significantly enhance the effectiveness of a warning system, and finally reduce the risk from shallow landslides in mountainous regions.

scholarly journals Effect of clinical mastitis on reproductive targets achievement in cows

2019 ◽  
Vol 26 ◽  
pp. 1-10
Author(s):  
Hector Nava-Trujillo
Keyword(s):  
Confidence Interval ◽  
Odds Ratio ◽  
Relative Frequency ◽  
Negative Impact ◽  
Clinical Mastitis ◽  
Lower Odds ◽  
Negative Effect

The aim of this study was to determine the effect of clinical mastitis occurring between calving and the first service on the percentage of cows that achieve two reproductive targets: be served before 70 days postpartum and be pregnant before 110 days postpartum (dpp). Relative frequency and odds ratio (OR) with the corresponding confidence interval (CI) were calculated. Fewer mastitic cows were served before 70 dpp than non-mastitic (24.86% vs 36.59% respectively P = 0.0137); mastitic cows had lower odds to be served than non-mastitic cows (OR: 0.57; 95% CI: 0.3679-0.8938, P = 0.0141). Fewer mastitic cows became pregnant before 110 dpp than non-mastitic cows (36.72% vs 50.73%, respectively, P = 0.006) and mastitic cows had lower odds to become pregnant than non-mastitic cows (OR: 0.56; 95% CI: 0.3739-0.8495, P = 0.0062).  Negative effect of clinical mastitis on percentage of cows served only was observed in primiparous cows, with 4.76% of mastitic cows being served in comparison with 30.19% of non-mastitic cows (P = 0.0017); primiparous mastitic cows had lower odds (0.11; 95% CI: 0.0249-0.5374, P = 0.0059) to be served than non-mastitic primiparous cows. Percentage of primiparous mastitic cows pregnant before 110 dpp was lower than non-mastitic cows (16.67% vs 37.74%, P = 0.0245) and mastitic cows had only 0.3300 odds (95% CI: 0.1234-0.8822, P = 0.0271) to become pregnant that primiparous non-mastitic. In multiparous, 42.96% of mastitic and 55.26% of non-mastitic cows (P = 0.0378) became pregnant before 110 dpp and mastitic cows had 0.6098 odd (95% CI: 0.3821-0.9730, P = 0.0380) to become pregnant than non-mastitic. In conclusion, clinical mastitis reduced the possibility of cows to be served and become pregnant during the first 70 and 110 dpp respectively, and the negative impact of clinical mastitis was more harmful in primiparous cows.

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