scholarly journals Assessment of Rainfall-Induced Landslide Distribution Based on Land Disturbance in Southern Taiwan

2021 ◽  
Vol 10 (4) ◽  
pp. 209
Author(s):  
Chih-Ming Tseng ◽  
Yie-Ruey Chen ◽  
Chwen-Ming Chang ◽  
Yung-Sheng Chue ◽  
Shun-Chieh Hsieh
Keyword(s):  
Satellite Image ◽  
Extreme Rainfall ◽  
Land Area ◽  
Rainfall Events ◽  
Land Disturbance ◽  
Bare Land ◽  
Southern Taiwan ◽  
The Impact ◽  
Landslide Distribution ◽  
The Relationship

This study explores the impact of rainfall on the followed-up landslides after a severe typhoon and the relationship between various rainfall events and the occurrence, scale, and regional characteristics of the landslides, including second landslides. Moreover, the influence of land disturbance was evaluated. The genetic adaptive neural network was used in combination with the texture analysis of the geographic information system for satellite image classification and interpretation to analyze land-use change and retrieve disaster records and surface information after five rainfall events from Typhoon Morakot (2009) to Typhoon Nanmadol (2011). The results revealed that except for extreme Morakot rains, the greater the degree of slope disturbance after rain, the larger the exposed slope. Extreme rainfall similar to Morakot strikes may have a greater impact on the bare land area than on slope disturbance. Moreover, the relationship between the bare land area and the index of land disturbance condition (ILDC) is positive, and the ratio of the bare land area to the quantity of bare land after each rainfall increases with the ILDC. With higher effective accumulative rainfall on the slope in the study area or greater slope disturbance, the landslide area at the second landslide point tended to increase.

scholarly journals The relationship between landslide activity and weather: examples from Hungary

2003 ◽  
Vol 3 (1/2) ◽  
pp. 43-52 ◽  
Author(s):  
J. Szabó
Keyword(s):  
Case Studies ◽  
Winter Precipitation ◽  
Unconsolidated Sediments ◽  
Rainfall Events ◽  
Landscape Type ◽  
Landslide Processes ◽  
Landscape Types ◽  
The Impact ◽  
The Relationship ◽  
Precipitation Events

Abstract. The paper presents the impact of irregular rainfall events triggering landslides in the regional context of landslides in Hungary. The author’s experience, gathered from decades of observations, confirms that landslide processes are strongly correlate with precipitation events in all three landscape types (hill regions of unconsolidated sediments; high bluffs along river banks and lake shores; mountains of Tertiary stratovolcanoes). Case studies for each landscape type underline that new landslides are triggered and old ones are reactivated by extreme winter precipitation events. This assertion is valid mainly for shallow and translational slides. Wet autumns favour landsliding, while the triggering influence of intense summer rainfalls is of a subordinate nature. A recent increasing problem lies in the fact that on previously unstable slopes, stabilised during longer dry intervals, an intensive cultivation starts, thus increasing the damage caused by movements during relatively infrequent wet winters.

The Impact of Rain Exposure During Loading of Wood Pellets for Ocean Shipment: An Experimental Study

2021 ◽  
Vol 64 (1) ◽  
pp. 253-258
Author(s):  
Jun Sian Lee ◽  
Shahab Sokhansanj ◽  
Anthony K. Lau ◽  
Jim Lim
Keyword(s):  
Experimental Study ◽  
List Type ◽  
Exploratory Research ◽  
Wood Pellets ◽  
Bulk Materials ◽  
The West ◽  
Rainfall Events ◽  
Fines Content ◽  
The Impact ◽  
The Relationship

HighlightsA cut-off curve was delineated that specifies the rainfall conditions at which loading of wood pellets must be stopped.The relationship between the amount of water sprayed and the pellet durability and fines content was quantified.Very light rainfall events (less than 0.5 mm h-1) had little impact on the durability of wood pellets.Abstract. On the west coast of Canada, port terminals are frequently exposed to seasonal rainfall events, which can impact the loading operations at the terminals. Wood pellets, one of the bulk materials frequently handled in Canadian ports, are known to disintegrate when exposed to water. However, the extent to which the exposed pellets degrade, in terms of their durability and fines content, is not quantified in the literature. This exploratory research quantifies the impact of liquid water on wood pellets and delineates a cut-off curve specifying the rainfall conditions at which the loading of wood pellets needs to be halted. For example, loading may continue for at least 30 min at rainfall intensities of less than 0.5 mm h-1 before the durability of the wood pellets drops from 99.5% to 96.5%. The results also showed that the durability and fines content of wetted pellets have a strong correlation with the amount of water that the wood pellets are exposed to. Keywords: Durability, Fines, Loading, Moisture content, Rain, Wood pellets.

Extreme rainfall events during and following heatwaves

2021 ◽  
Author(s):  
Christoph Sauter ◽  
Christopher White ◽  
Hayley Fowler ◽  
Seth Westra
Keyword(s):  
Natural Hazards ◽  
Rainfall Intensity ◽  
Daily Rainfall ◽  
Extreme Rainfall ◽  
Extreme Rainfall Events ◽  
Rainfall Events ◽  
Rainfall Extremes ◽  
Average Rainfall ◽  
Time Of Year ◽  
The Impact

<p>Heatwaves and extreme rainfall events are natural hazards that can have severe impacts on society. The relationship between temperature and extreme rainfall has received scientific attention with studies focussing on how single daily or sub-daily rainfall extremes are related to day-to-day temperature variability. However, the impact multi-day heatwaves have on sub-daily extreme rainfall events and how extreme rainfall properties change during different stages of a heatwave remains mostly unexplored.</p><p>In this study, we analyse sub-daily rainfall records across Australia, a country that experiences severe natural hazards on a frequent basis, and determine their extreme rainfall properties, such as rainfall intensity, duration and frequency during SH-summer heatwaves. These properties are then compared to extreme rainfall properties found outside heatwaves, but during the same time of year, to examine to what extent they differ from normal conditions. We also conduct a spatial analysis to investigate any spatial patterns that arise.</p><p>We find that rainfall breaking heatwaves is often more extreme than average rainfall during the same time of year. This is especially prominent on the eastern and south-eastern Australian coast, where frequency and intensity of sub-daily rainfall extremes show an increase during the last day or the day immediately after a heatwave. We also find that although during heatwaves the average rainfall amount and duration decreases, there is an increase in sub-daily rainfall intensity when compared to conditions outside heatwaves. This implies that even though Australian heatwaves are generally characterised by dry conditions, rainfall occurrences within heatwaves are more intense.</p><p>Both heatwaves and extreme rainfall events pose great challenges for many sectors such as agriculture, and especially if they occur together. Understanding how and to what degree these events co-occur could help mitigate the impacts caused by them.</p>

scholarly journals Riverbed Migrations in Western Taiwan under Climate Change

Water ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1631 ◽  
Author(s):  
Yi-Chiung Chao ◽  
Chi-Wen Chen ◽  
Hsin-Chi Li ◽  
Yung-Ming Chen
Keyword(s):  
Climate Change ◽  
21St Century ◽  
Peak Flow ◽  
Extreme Rainfall ◽  
Base Period ◽  
Extreme Rainfall Events ◽  
Rainfall Events ◽  
Flow Discharge ◽  
The Future ◽  
The Impact

In recent years, extreme weather phenomena have occurred worldwide, resulting in many catastrophic disasters. Under the impact of climate change, the frequency of extreme rainfall events in Taiwan will increase, according to a report on climate change in Taiwan. This study analyzed riverbed migrations, such as degradation and aggradation, caused by extreme rainfall events under climate change for the Choshui River, Taiwan. We used the CCHE1D model to simulate changes in flow discharge and riverbed caused by typhoon events for the base period (1979–2003) and the end of the 21st century (2075–2099) according to the climate change scenario of representative concentration pathways 8.5 (RCP8.5) and dynamical downscaling of rainfall data in Taiwan. According to the results on flow discharge, at the end of the 21st century, the average peak flow during extreme rainfall events will increase by 20% relative to the base period, but the time required to reach the peak will be 8 h shorter than that in the base period. In terms of the results of degradation and aggradation of the riverbed, at the end of the 21st century, the amount of aggradation will increase by 33% over that of the base period. In the future, upstream sediment will be blocked by the Chichi weir, increasing the severity of scouring downstream. In addition, due to the increased peak flow discharge in the future, the scouring of the pier may be more serious than it is currently. More detailed 2D or 3D hydrological models are necessary in future works, which could adequately address the erosive phenomena created by bridge piers. Our results indicate that not only will flood disasters occur within a shorter time duration, but the catchment will also face more severe degradation and aggradation in the future.

scholarly journals The impact of atmospheric rivers on rainfall in New Zealand

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jingxiang Shu ◽  
Asaad Y. Shamseldin ◽  
Evan Weller
Keyword(s):  
New Zealand ◽  
Austral Summer ◽  
Daily Rainfall ◽  
Extreme Rainfall ◽  
Detection Algorithm ◽  
Extreme Rainfall Events ◽  
Rainfall Events ◽  
Atmospheric Rivers ◽  
Hydrological Hazards ◽  
The Impact

AbstractThis study quantifies the impact of atmospheric rivers (ARs) on rainfall in New Zealand. Using an automated AR detection algorithm, daily rainfall records from 654 rain gauges, and various atmospheric reanalysis datasets, we investigate the climatology of ARs, the characteristics of landfalling ARs, the contribution of ARs to annual and seasonal rainfall totals, and extreme rainfall events between 1979 and 2018 across the country. Results indicate that these filamentary synoptic features play an essential role in regional water resources and are responsible for many extreme rainfall events on the western side of mountainous areas and northern New Zealand. In these regions, depending on the season, 40–86% of the rainfall totals and 50–98% of extreme rainfall events are shown to be associated with ARs, with the largest contributions predominantly occurring during the austral summer. Furthermore, the median daily rainfall associated with ARs is 2–3 times than that associated with other storms. The results of this study extend the knowledge on the critical roles of ARs on hydrology and highlight the need for further investigation on the landfalling AR physical processes in relation to global circulation features and AR sources, and hydrological hazards caused by ARs in New Zealand.

scholarly journals Relationship Between Extreme Rainfall and Surface Temperature in Sicily (Italy)

10.29007/rtts ◽  
2018 ◽  
Author(s):  
Dario Pumo ◽  
Giuseppina Carlino ◽  
Elisa Arnone ◽  
Leonardo Noto
Keyword(s):  
Surface Temperature ◽  
Extreme Rainfall ◽  
Extreme Rainfall Events ◽  
Rainfall Events ◽  
Scaling Relationship ◽  
Using Data ◽  
Semi Arid Region ◽  
Increasing Temperature ◽  
The Relationship ◽  
Different Parts

The study of the relationship between extreme rainfall events and surface temperature represents an important issue in hydrology and meteorology and it could be of capital importance for evaluating the effect of global warming on future precipitation. Various approaches have been tested across different parts of the world, and, in many cases, it has been observed an intensification of precipitation with increasing temperature consistently with the thermodynamic Clausius-Clapeyron relation (CC-rate of 6-7% °C-1), according to which a warmer atmosphere is capable of holding more moisture. Nevertheless, in different locations, the scaling rate between temperature and extreme precipitation has resulted significantly different with respect to the CC-rate, in some cases sensibly higher (super-CC) and in other relevantly lower (sub-CC). In this work, an analysis of the scaling relationship between sub-daily extreme rainfall events and surface temperature is carried out, using data from a large number of rain and temperature gauges across Sicily (Italy). Results highlight the relevant importance of some modeling choices and, particularly, of rainfall duration, for this type of analysis in semi-arid region. An overall sub-CC scaling rate has been detected for most part of the region.

scholarly journals Association of geopotential height patterns with heavy rainfall events in Cyprus

2010 ◽  
Vol 23 ◽  
pp. 73-78 ◽  
Author(s):  
F. Tymvios ◽  
K. Savvidou ◽  
S. C. Michaelides
Keyword(s):  
Geopotential Height ◽  
Heavy Rainfall ◽  
Eastern Mediterranean ◽  
Statistical Processing ◽  
Extreme Rainfall ◽  
Classification Performance ◽  
Extreme Rainfall Events ◽  
Rainfall Events ◽  
The Relationship ◽  
Heavy Rainfall Events

Abstract. Dynamically induced rainfall is strongly connected with synoptic atmospheric circulation patterns at the upper levels. This study investigates the relationship between days of high precipitation volume events in the eastern Mediterranean and the associated geopotential height patterns at 500 hPa. To reduce the number of different patterns and to simplify the statistical processing, the input days were classified into clusters of synoptic cases having similar characteristics, by utilizing Kohonen Self Organizing Maps (SOM) architecture. Using this architecture, synoptic patterns were grouped into 9, 18, 27 and 36 clusters which were subsequently used in the analysis. The classification performance was tested by applying the method to extreme rainfall events in the eastern Mediterranean. The relationship of the synoptic upper air patterns (500 hPa height) and surface features (heavy rainfall events) was established, while the 36 member classification proved to be the most efficient.

scholarly journals Hydrological appraisal of operational weather radar rainfall estimates in the context of different modelling structures

2013 ◽  
Vol 10 (8) ◽  
pp. 10495-10534
Author(s):  
D. Zhu ◽  
Y. Xuan ◽  
I. Cluckie
Keyword(s):  
Hydrological Model ◽  
Scale Effects ◽  
Model Performance ◽  
Extreme Rainfall ◽  
Distributed Model ◽  
Catchment Scale ◽  
Radar Rainfall ◽  
Rainfall Events ◽  
The Impact ◽  
Rainfall Estimates

Abstract. Radar rainfall estimates have become increasingly available for hydrological modellers over recent years, especially for flood forecasting and warning over poorly gauged catchments. However, the impact of using radar rainfall as compared with conventional raingauge inputs, with respect to various hydrological model structures, remains unclear and yet to be addressed. In the study presented by this paper, we analysed the flow simulations of the Upper Medway catchment of Southeast England using the UK NIMROD radar rainfall estimates using three hydrological models based upon three very different structures, e.g. a physically based distributed MIKE SHE model, a lumped conceptual model PDM and an event-based unit hydrograph model PRTF. We focused on the sensitivity of simulations in relation to the storm types and various rainfall intensities. The uncertainty in radar-rainfall estimates, scale effects and extreme rainfall were examined in order to quantify the performance of the radar. We found that radar rainfall estimates were lower than raingauge measurements in high rainfall rates; the resolutions of radar rainfall data had insignificant impact at this catchment scale in the case of evenly distributed rainfall events but was obvious otherwise for high-intensity, localised rainfall events with great spatial heterogeneity. As to hydrological model performance, the distributed model had consistent reliable and good performance on peak simulation with all the rainfall types tested in this study.

scholarly journals Spatio-temporal Variability and Trends of Mean and Extreme Rainfall Events in the Sudano-sahelian Region of Cameroon

2021 ◽  
Author(s):  
Ibrahim NJOUENWET ◽  
Lucie A. Djiotang Tchotchou ◽  
Brian Odhiambo Ayugi ◽  
Guy Merlin Guenang ◽  
Derbetini A. Vondou ◽  
...  
Keyword(s):  
Climate Change ◽  
Extreme Rainfall ◽  
Temporal Variations ◽  
Annual Rainfall ◽  
Drought Risk ◽  
Extreme Rainfall Events ◽  
Rainfall Events ◽  
Precipitation Concentration ◽  
Spatio Temporal ◽  
The Impact

Abstract The Sudano-Sahelian region of Cameroon is mainly drained by the Benue, Chari and Logone rivers, which are very useful for water resources, especially for irrigation, hydropower generation, and navigation. Long-term changes in mean and extreme rainfall events in the region may be of crucial importance in understanding the impact of climate change. Daily and monthly rainfall data from twenty-five synoptic stations in the study area from 1980 to 2019 and extreme indices from the Expert Team on Climate Change Detection and Indices (ETCCDI) measurements were estimated using the non-parametric Modified Mann-Kendall test and the Sen slope estimator. The precipitation concentration index (PCI), the precipitation concentration degree (PCD), and the precipitation concentration period (PCP) were used to explore the spatio-temporal variations in the characteristics of rainfall concentrations. An increase in extreme rainfall events was observed, leading to an upward trend in mean annual. Trends in consecutive dry days (CDD) are significantly increasing in most parts of the study area. This could mean that the prevalence of drought risk is higher in the study area. Overall, the increase in annual rainfall could benefit the hydro-power sector, agricultural irrigation, the availability of potable water sources, and food security.

scholarly journals Spatial Clustering of Dengue Fever Incidence and Its Association with Surrounding Greenness

2018 ◽  
Vol 15 (9) ◽  
pp. 1869 ◽  
Author(s):  
Chi-Chieh Huang ◽  
Tuen Tam ◽  
Yinq-Rong Chern ◽  
Shih-Chun Lung ◽  
Nai-Tzu Chen ◽  
...  
Keyword(s):  
Land Use ◽  
Spatial Autocorrelation ◽  
Dengue Fever ◽  
Vegetation Index ◽  
Green Space ◽  
Hot Spot ◽  
Southern Taiwan ◽  
The Impact ◽  
The Relationship ◽  
Green Land

With more than 58,000 cases reported by the country’s Centers for Disease Control, the dengue outbreaks from 2014 to 2015 seriously impacted the southern part of Taiwan. This study aims to assess the spatial autocorrelation of the dengue fever (DF) outbreak in southern Taiwan in 2014 and 2015, and to further understand the effects of green space (such as forests, farms, grass, and parks) allocation on DF. In this study, two different greenness indexes were used. The first green metric, the normalized difference vegetation index (NDVI), was provided by the long-term NASA MODIS satellite NDVI database, which quantifies and represents the overall vegetation greenness. The latest 2013 land use survey GIS database completed by the National Land Surveying and Mapping Center was obtained to access another green metric, green land use in Taiwan. We first used Spearman’s rho to find out the relationship between DF and green space, and then three spatial autocorrelation methods, including Global Moran’s I, high/low clustering, and Hot Spot were employed to assess the spatial autocorrelation of DF outbreak. In considering the impact of social and environmental factors in DF, we used generalized linear mixed models (GLMM) to further clarify the relationship between different types of green land use and dengue cases. Results of spatial autocorrelation analysis showed a high aggregation of dengue epidemic in southern Taiwan, and the metropolitan areas were the main hotspots. Results of correlation analysis and GLMM showed a positive correlation between parks and dengue fever, and the other five green space metrics and land types revealed a negative association with DF. Our findings may be an important asset for improving surveillance and control interventions for dengue.

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