A Global Assessment of Non-Stationarity in Extreme Precipitation

2020 ◽  
Author(s):  
Razi Sheikholeslami ◽  
Simon Michael Papalexiou ◽  
Martyn Clark
Keyword(s):  
Extreme Precipitation ◽  
Extreme Rainfall ◽  
Heavy Precipitation ◽  
Global Scale ◽  
Flood Frequency ◽  
Human Society ◽  
Extreme Rainfall Events ◽  
The Future ◽  
Resilient Infrastructure ◽  
Earth System Models

<p>Rapid urban development, along with human modifications in river discharge (both frequency and magnitude) increase the need to design safe and resilient infrastructure. In addition, continental-domain studies show that there are significant changes in the intensity and frequency of the extreme rainfall events. Importantly, Earth System Models predict that these changes will continue to grow in the future. Consequently, flood frequency from heavy precipitation events is expected to increase, thereby threatening human society and the environment. Therefore, the stationary climate assumption — the idea that the future variability of the system will remain within the limits observed in the past record — may not be valid and should be carefully examined. Despite the existing awareness of potential non-stationarity, there has been a limited research on analysis of non-stationary of extreme precipitation at the global scale. This motivated us to conduct a comprehensive global study to compare the performance of non-stationary and stationary models in describing precipitation extremes.</p>

scholarly journals Assessment of Heavy Rainfall using GPM- IMERG Satellite Product over Nepal

Jalawaayu ◽  
2021 ◽  
Vol 1 (2) ◽  
pp. 79-95
Author(s):  
Nirmala Regmi ◽  
Bikash Nepal ◽  
Shankar Sharma ◽  
Dibas Shrestha ◽  
Govind Kumar Jha
Keyword(s):  
Extreme Precipitation ◽  
Extreme Rainfall ◽  
Heavy Precipitation ◽  
Mode Analysis ◽  
Extreme Rainfall Events ◽  
Precipitation Measurement ◽  
Object Based ◽  
Evaluation Mode ◽  
Global Precipitation Measurement ◽  
Global Precipitation

This study evaluates the Integrated Multi-satellite Retrievals from Global Precipitation Measurement (IMERG) final product’s ability to represent the extreme precipitation against 310 observations from Nepal between 2015 and 2017. Additionally, Method of Object-based Diagnostic Evaluation (MODE) analysis was also performed to analyze IMERG ability to capture actual spatial distribution of the rainfall extremes. Both datasets show the extreme rainfall events are mostly concentrated at southern low land areas of the country. MODE tool further revealed the slight shifting of heavy precipitation location by IMERG product as compared to observation. It is also noted that, as precipitation intensity increases (threshold values of rainfall), the number of extreme events decreases. Moreover, this work provides a systematic quantification of the performance of IMERG gauge calibrated product and its applicability in extreme precipitation over mountainous region.

scholarly journals Spatial Heterogeneity Analysis of Short-Duration Extreme Rainfall Events in Megacities in China

Water ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3364 ◽  
Author(s):  
Qi Zhuang ◽  
Shuguang Liu ◽  
Zhengzheng Zhou
Keyword(s):  
Spatial Heterogeneity ◽  
Short Duration ◽  
Urban Areas ◽  
Spatial Association ◽  
Extreme Rainfall ◽  
Flood Frequency ◽  
Flood Frequency Analysis ◽  
Extreme Rainfall Events ◽  
Rainfall Events ◽  
Design Storm

Given the fact that researchers require more specific spatial rainfall information for storm flood calculation, hydrological risk assessment, and water budget estimates, there is a growing need to analyze the spatial heterogeneity of rainfall accurately. This paper provides insight into rainfall spatial heterogeneity in urban areas based on statistical analysis methods. An ensemble of short-duration (3-h) extreme rainfall events for four megacities in China are extracted from a high-resolution gridded rainfall dataset (resolution of 30 min in time, 0.1° × 0.1° in space). Under the heterogeneity framework using Moran’s I, LISA (Local Indicators of Spatial Association), and semi-variance, the multi-scale spatial variability of extreme rainfall is identified and assessed in Shanghai (SH), Beijing (BJ), Guangzhou (GZ), and Shenzhen (SZ). The results show that there is a pronounced spatial heterogeneity of short-duration extreme rainfall in the four cities. Heterogeneous characteristics of rainfall within location, range, and directions are closely linked to the different urban growth in four cities. The results also suggest that the spatial distribution of rainfall cannot be neglected in the design storm in urban areas. This paper constitutes a useful contribution to quantifying the degree of spatial heterogeneity and supports an improved understanding of rainfall/flood frequency analysis in megacities.

A Diagnosis of the 1979–2005 Extreme Rainfall Events in the Southeastern United States with Isentropic Moisture Tracing

2010 ◽  
Vol 138 (4) ◽  
pp. 1172-1185 ◽  
Author(s):  
Steven C. Chan ◽  
Vasubandhu Misra
Keyword(s):  
United States ◽  
Land Surface ◽  
Southeastern United States ◽  
Extreme Rainfall ◽  
Heavy Precipitation ◽  
Extreme Rainfall Events ◽  
Moisture Sources ◽  
Precipitation Total ◽  
Precipitation Anomalies ◽  
Precipitation Events

Abstract A detailed analysis is performed to better understand the interannual and subseasonal variability of moisture sources of major recent dry (1980, 1990, and 2000) and wet (1994, 2003, and 2005) June–August (JJA) seasons in the southeastern United States. Wet (dry) JJAs show an increased (decreased) standard deviation of daily precipitation. Whereas most days during dry JJAs have little or no precipitation, wet JJAs contain more days with significant precipitation and a large increase of heavy (+10 mm) precipitation days. At least two tropical cyclone/depression landfalls occur in the southeastern United States during wet JJAs, whereas none occur during dry JJAs. The trajectory analysis suggests significant local recycling of moisture, implying that land surface feedback has the potential to enhance (suppress) precipitation anomalies during a wet (dry) JJA. Remote moisture sources during heavy precipitation events are very similar between wet and dry JJAs. The distinction between wet and dry JJAs lies in the frequency of heavy precipitation events. During the wet JJAs, heavy precipitation events contribute to more than half of the JJA precipitation total.

scholarly journals Characterizing past and future trend and frequency of extreme rainfall in urban catchments: a case study

2020 ◽  
Vol 3 (1) ◽  
pp. 288-305
Author(s):  
Philip Mzava ◽  
Patrick Valimba ◽  
Joel Nobert
Keyword(s):  
Trend Analysis ◽  
Rainfall Variability ◽  
Extreme Rainfall ◽  
Dar Es Salaam ◽  
Extreme Rainfall Events ◽  
Maximum Rainfall ◽  
Rainfall Events ◽  
The Past ◽  
The Future ◽  
Urban Catchments

Abstract Urban communities in developing countries are one of the most vulnerable areas to extreme rainfall events. The availability of local information on extreme rainfall is therefore critical for proper planning and management of urban flooding impacts. This study examined the past and future characteristics of extreme rainfall in the urban catchments of Dar es Salaam, Tanzania. Investigation of trends and frequency of annual, seasonal and extreme rainfall was conducted, with the period 1967–2017 taken as the past scenario and 2018–2050 as the future scenario; using data from four key ground-based weather stations and RCM data respectively. Mann–Kendall trend analysis and Sen's slope estimator were used in studying changes in rainfall variability. Frequencies of extreme rainfall events were modeled using the Generalized Pareto model. Overall, the results of trend analysis provided evidence of a significant increase in annual and seasonal maximum rainfall and intensification of extreme rainfall in the future under the RCP4.5 CO2 concentration scenario. It was determined that extreme rainfall will become more frequent in the future, and their intensities were observed to increase approximately between 20 and 25% relative to the past. The findings of this study may help to develop adaptation strategies for urban flood control in Dar es Salaam.

Exposure analysis of Chinese railways under the Change of Extreme-Precipitation in the future

2020 ◽  
Author(s):  
Jing Zhao ◽  
Kai liu ◽  
Ming Wang
Keyword(s):  
Global Warming ◽  
Return Period ◽  
Extreme Precipitation ◽  
Climate Model ◽  
Precipitation Amount ◽  
Extreme Rainfall ◽  
Railway Planning ◽  
The Future ◽  
Railway System ◽  
Climate Model Simulations

<p>Abstract: Rainfall-induced disaster is the most frequent disaster affected Chinese Railway System. Climate change will lead to more extreme rainfall in the future. A better understanding of extreme precipitation in the future and the exposure of railway infrastructures to extreme precipitation will facilitate railway planning and disaster risk management. This paper employs climate model simulations to calculate the changes of the extreme precipitation under different global warming scenarios. The return periods of the present 50-yr/100-yr return-period precipitation amount in the future are obtained. Based on this, the changes of the exposure of Chinese railways to extreme precipitation are analyzed. The results reveal that 58.61% (55.46) of China’s region will experience an increase in the 50-yr(100-yr) return-period precipitation under 1.5°C warming in comparison with the present period (2001–2020), the value will be 64.44% and 59.53% due to the additional 0.5°C warming. By calculating the exposure of Chinese railways, we found that 28.49% (32.15) of China's railways are in the region where 50-yr return-period rainfall at this stage will occur less than 20 years under 1.5°C (2.0°C) warming, and 36.85% (41.39)of China's railways are in the region where 100-yr return-period rainfall at this stage will occur less than 50 years under 1.5°C (2.0°C) warming in the future. This study quantified the exposure of China’s railway to extreme precipitation under the 1.5°C/2.0°C global warming. The results provided in this study have profound significance for the fortification planning of China's railway system for rainfall-induced disasters and provide useful experience for other countries.</p>

Global-scale teleconnections of extreme rainfall revealed by complex networks

2020 ◽  
Author(s):  
Niklas Boers ◽  
Bedartha Goswami ◽  
Aljoscha Rheinwalt ◽  
Bodo Bookhagen ◽  
Brian Hoskins ◽  
...  
Keyword(s):  
Complex Networks ◽  
Atmospheric Circulation ◽  
Rossby Waves ◽  
Extreme Rainfall ◽  
Global Scale ◽  
Extreme Rainfall Events ◽  
Rainfall Events ◽  
Atmospheric Circulation Patterns ◽  
South Central ◽  
Circulation Patterns

<p>Extreme rainfall events are often coupled across long spatial distances due to atmospheric teleconnections. Revealing such linkages is important for our understanding of extreme events and related atmospheric circulation patterns, but also for enhancing the forecast skill of such events [1]. Here, we present recent results [2] on how complex networks can be employed to discover extreme rainfall teleconnections from high-resolution satellite data. Our method allows to quantitatively distinguish regional weather systems from global-scale teleconnections coupling the individual weather systems. Several lines of evidence suggest that the most relevant mechanisms for global-scale teleconnections of extreme rainfall events are related to atmospheric Rossby waves. We exemplify our approach with a focus on extreme rainfall events in the mountain regions of South-Central Asia (including Northern Pakistan and India), and show that they are statistically significantly coupled to preceding events in Europe as well as succeeding events in eastern China. An analysis of the corresponding atmospheric circulation patterns shows that a previously revealed, quasi-stationary Rossby wave termed the ‘silk road pattern’ [3] is responsible for this instance of long-range coupling between extreme rainfall events. Overall, our findings give new insights into the connections between atmospheric Rossby waves and extreme rainfall events, and thus into the potential predictability of related natural hazards. Moreover, they give promising clues in how to constrain state-of-the-art climate models with respect to their simulation of extreme rainfall. </p><p> </p><p>[1] B. Hoskins: The potential for skill across the range of the seamless weather-climate prediction problem: A stimulus for our science, QJRMS 2013</p><p>[2] N. Boers, B. Goswami, A. Rheinwalt, B. Bookhagen, B. Hoskins, J. Kurths: Complex networks reveal global pattern of extreme-rainfall teleconnections, Nature 2019</p><p>[3] T. Enomoto, B. Hoskins, Y. Matsuda: The formation mechanism of the Bonin high in August, QJRMS 2003</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 Characteristics, Origins, and Impacts of Summertime Extreme Precipitation in the Lake Mead Watershed

2020 ◽  
Vol 33 (7) ◽  
pp. 2663-2680 ◽  
Author(s):  
Michael D. Sierks ◽  
Julie Kalansky ◽  
Forest Cannon ◽  
F. M. Ralph
Keyword(s):  
North American ◽  
Extreme Precipitation ◽  
Extreme Rainfall ◽  
North American Monsoon ◽  
Lake Mead ◽  
Extreme Rainfall Events ◽  
Rainfall Events ◽  
The North ◽  
The U.S ◽  
Tier I

AbstractThe North American monsoon (NAM) is the main driver of summertime climate variability in the U.S. Southwest. Previous studies of the NAM have primarily focused on the Tier I region of the North American Monsoon Experiment (NAME), spanning central-western Mexico, southern Arizona, and New Mexico. This study, however, presents a climatological characterization of summertime precipitation, defined as July–September (JAS), in the Lake Mead watershed, located in the NAME Tier II region. Spatiotemporal variability of JAS rainfall is examined from 1981 to 2016 using gridded precipitation data and the meteorological mechanisms that account for this variability are investigated using reanalyses. The importance of the number of wet days (24-h rainfall ≥1 mm) and extreme rainfall events (95th percentile of wet days) to the total JAS precipitation is examined and shows extreme events playing a larger role in the west and central basin. An investigation into the dynamical drivers of extreme rainfall events indicates that anticyclonic Rossby wave breaking (RWB) in the midlatitude westerlies over the U.S. West Coast is associated with 89% of precipitation events >10 mm (98th percentile of wet days) over the Lake Mead basin. This is in contrast to the NAME Tier I region where easterly upper-level disturbances such as inverted troughs are the dominant driver of extreme precipitation. Due to the synoptic nature of RWB events, corresponding impacts and hazards extend beyond the Lake Mead watershed are relevant for the greater U.S. Southwest.

scholarly journals Extreme Rainfall and Hydro-Geo-Meteorological Disaster Risk in 1.5, 2.0, and 4.0°C Global Warming Scenarios: An Analysis for Brazil

2021 ◽  
Vol 3 ◽  
Author(s):  
Jose A. Marengo ◽  
Pedro I. Camarinha ◽  
Lincoln M. Alves ◽  
Fabio Diniz ◽  
Richard A. Betts
Keyword(s):  
Global Warming ◽  
Climate Models ◽  
Extreme Rainfall ◽  
Heavy Precipitation ◽  
Early Warning Systems ◽  
Disaster Risk ◽  
Remarkable Change ◽  
Extreme Rainfall Events ◽  
Rainfall Events ◽  
Metropolitan Regions

With the inclusion of demographic characteristics of the population living in vulnerable areas, a combination of empirical and climate models was used to project changes to climate and in hydro-geo-meteorological disasters in Brazil. This study investigated the effect of extreme rainfall changes and the risk of floods and landslides under 1.5, 2.0, and 4.0°C global warming levels (GWLs). Projections from a large ensemble of pre-CMIP6 models and different warming levels show a remarkable change in heavy precipitation. As a result, with increasing warming this enhances the risk of landslides and flash floods in the context of climate change. Comparisons of vulnerability and change in potential impacts of landslides and floods show that three regions, highly densely populated areas, are the most exposed to landslides and floods. The Southern and Southeastern of Brazil stand out, including metropolitan regions with high economic development and densely populated, which may be those where disasters can intensify both in terms of frequency and magnitude. The eastern portion of the Northeast is also signaled as one of the affected regions due to its high vulnerability and exposure since the present period, although the projections of future climate do not allow conclusive results regarding the intensification of extreme rainfall events in scenarios below 4°C. The main metropolitan regions and tourist resorts, and key infrastructure in Brazil are located in those regions. This study highlights the importance of environmental policies to protect human lives and minimize financial losses in the coming decades and reinforces the need for decision-making, monitoring, and early warning systems to better manage disasters as part of disaster risk reduction risk management.

scholarly journals UAV-based evaluation of morphological changes induced by extreme rainfall events in meandering rivers

PLoS ONE ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. e0241293
Author(s):  
Semih Sami Akay ◽  
Orkan Özcan ◽  
Füsun Balık Şanlı ◽  
Tolga Görüm ◽  
Ömer Lütfi Şen ◽  
...  
Keyword(s):  
Water Level ◽  
Extreme Precipitation ◽  
Morphological Changes ◽  
Extreme Rainfall ◽  
Precipitation Event ◽  
River Channels ◽  
Meandering Rivers ◽  
Erosion And Deposition ◽  
Extreme Rainfall Events ◽  
Rainfall Events

Morphological changes, caused by the erosion and deposition processes due to water discharge and sediment flux occur, in the banks along the river channels and in the estuaries. Flow rate is one of the most important factors that can change river morphology. The geometric shapes of the meanders and the river flow parameters are crucial components in the areas where erosion or deposition occurs in the meandering rivers. Extreme precipitation triggers erosion on the slopes, which causes significant morphological changes in large areas during and after the event. The flow and sediment amount observed in a river basin with extreme precipitation increases and exceeds the long-term average value. Hereby, erosion severity can be determined by performing spatial analyses on remotely sensed imagery acquired before and after an extreme precipitation event. Changes of erosion and deposition along the river channels and overspill channels can be examined by comparing multi-temporal Unmanned Aerial Vehicle (UAV) based Digital Surface Model (DSM) data. In this study, morphological changes in the Büyük Menderes River located in the western Turkey, were monitored with pre-flood (June 2018), during flood (January 2019), and post-flood (September 2019) UAV surveys, and the spatial and volumetric changes of eroded/deposited sediment were quantified. For this purpose, the DSAS (Digital Shoreline Analysis System) method and the DEM of Difference (DoD) method were used to determine the changes on the riverbank and to compare the periodic volumetric morphological changes. Hereby, Structure from Motion (SfM) photogrammetry technique was exploited to a low-cost UAV derived imagery to achieve riverbank, areal and volumetric changes following the extreme rainfall events extracted from the time series of Tropical Rainfall Measuring Mission (TRMM) satellite data. The change analyses were performed to figure out the periodic morphodynamic variations and the impact of the flood on the selected meandering structures. In conclusion, although the river water level increased by 0.4–5.9 meters with the flood occurred in January 2019, the sediment deposition areas reformed after the flood event, as the water level decreased. Two-year monitoring revealed that the sinuosity index (SI) values changed during the flood approached the pre-flood values over time. Moreover, it was observed that the amount of the deposited sediments in September 2019 approached that of June 2018.

Sign in / Sign up

Export Citation Format

Share Document