scholarly journals Analysis of precipitation extremes in the Taihu Basin of China based on the regional L-moment method

2016 ◽  
Vol 48 (2) ◽  
pp. 468-479 ◽  
Author(s):  
Zhengzheng Zhou ◽  
Shuguang Liu ◽  
Yan Hu ◽  
Yuyin Liang ◽  
Hejuan Lin ◽  
...  
Keyword(s):  
Urban Areas ◽  
Precipitation Extremes ◽  
Partial Duration Series ◽  
Site Analysis ◽  
Taihu Basin ◽  
Extreme Precipitation Events ◽  
Severe Flood ◽  
L Moments ◽  
Food Design ◽  
Precipitation Events

China has suffered from increasingly severe flood events in recent years, most of which are caused by heavy rains. The substantial casualties and damage caused by flooding necessitates a better understanding of precipitation extremes, especially in heavily populated urban areas. Based on L-moments from a regional perspective, this paper analyzes precipitation extremes in the Taihu Basin, utilizing annual maximum daily precipitation and partial duration series at 96 rain gages. The comparison of regional and at-site analysis results shows that the former provides more robust estimates, especially in the upper tail of a distribution (higher quantiles). Also, the use of partial duration series, which captures more information about extreme events, was found to be preferable to describe the extreme precipitation events in the Taihu Basin. Given the recently observed more frequent occurrence and greater magnitude of precipitation extremes, it is suggested that the food design standard used in the basin should be updated, especially for the urbanizing zones.

Analysing urban floods and combined sewer overflows in a changing climate

2011 ◽  
Vol 2 (4) ◽  
pp. 260-271 ◽  
Author(s):  
V. Nilsen ◽  
J. A. Lier ◽  
J. T. Bjerkholt ◽  
O. G. Lindholm
Keyword(s):  
Climate Change ◽  
Time Series ◽  
Urban Areas ◽  
Convective Precipitation ◽  
Urban Drainage ◽  
Combined Sewer Overflows ◽  
Extreme Precipitation Events ◽  
Combined Sewer ◽  
Sewer Overflows ◽  
Precipitation Events

Climate change is expected to lead to an increased frequency and intensity of extreme precipitation events. For urban drainage, the primary adverse effects are more frequent and severe sewer overloading and flooding in urban areas, and higher discharges through combined sewer overflows (CSO). For assessing the possible effects of climate change, urban drainage models are run with climate-change-adjusted input data. However, current climate models are run on a spatial–temporal scale that is too coarse to resolve processes relevant to urban drainage modelling, in particular convective precipitation events. In the work reported here the delta-change method was used to develop a high-resolution time series of precipitation for the period 2071–2100 based on a recently produced climate model precipitation time series for Oslo. The present and future performance of the sewer networks was determined using MOUSE software. The simulations indicated future increases in annual CSO discharge of 33% when comparing years of maximum annual runoff. There is also an 83% increase in annual CSO discharge when comparing years of maximum annual precipitation. In addition, there are increases in the flooding of manholes and increased levels of backwater in pipes, which translates into more flooding of basements.

scholarly journals Spatiotemporal Changes in Extreme Precipitation and Its Dependence on Topography over the Poyang Lake Basin, China

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Xianghu Li ◽  
Qi Hu
Keyword(s):  
Water Resources ◽  
Extreme Precipitation ◽  
Poyang Lake ◽  
Precipitation Extremes ◽  
Lake Basin ◽  
Extreme Precipitation Events ◽  
Poyang Lake Basin ◽  
Spatiotemporal Changes ◽  
Increasing Trends ◽  
Precipitation Events

Spatiotemporal changes in extreme precipitation at local scales in the context of climate warming are overwhelmingly important for prevention and mitigation of water-related disasters and also provide critical information for effective water resources management. In this study, the variability and trends of extreme precipitation in both time and space in the Poyang Lake basin over the period of 1960–2012 are analyzed. Also, changes in precipitation extremes with topography are investigated, and possible causes are briefly discussed. The results show that extreme precipitation over the Poyang Lake basin is intensified during the last 50 years, especially the increasing trends are more significant before the end of the 1990s. Moreover, high contribution rates of extreme precipitation to the total rainfall (40–60%) indicated that extreme precipitation plays an important role to the total water resources in this area. The precipitation extremes also exhibited a significant spatial dependence in the basin. The northeastern and eastern areas are exposed to high risk of flood disaster with the higher frequency of extreme precipitation events. In addition, the distribution of precipitation extremes had a clear dependence on elevation, and the topography is an important factor affecting the variability of extreme precipitation over the Poyang Lake basin.

scholarly journals Evaluation of NASA’s MERRA Precipitation Product in Reproducing the Observed Trend and Distribution of Extreme Precipitation Events in the United States

2016 ◽  
Vol 17 (2) ◽  
pp. 693-711 ◽  
Author(s):  
Hamed Ashouri ◽  
Soroosh Sorooshian ◽  
Kuo-Lin Hsu ◽  
Michael G. Bosilovich ◽  
Jaechoul Lee ◽  
...  
Keyword(s):  
United States ◽  
Extreme Precipitation ◽  
Gulf Coast ◽  
The United States ◽  
Value Theory ◽  
Extreme Value ◽  
Precipitation Extremes ◽  
Precipitation Product ◽  
Extreme Precipitation Events ◽  
Precipitation Events

Abstract This study evaluates the performance of NASA’s Modern-Era Retrospective Analysis for Research and Applications (MERRA) precipitation product in reproducing the trend and distribution of extreme precipitation events. Utilizing the extreme value theory, time-invariant and time-variant extreme value distributions are developed to model the trends and changes in the patterns of extreme precipitation events over the contiguous United States during 1979–2010. The Climate Prediction Center (CPC) U.S. Unified gridded observation data are used as the observational dataset. The CPC analysis shows that the eastern and western parts of the United States are experiencing positive and negative trends in annual maxima, respectively. The continental-scale patterns of change found in MERRA seem to reasonably mirror the observed patterns of change found in CPC. This is not previously expected, given the difficulty in constraining precipitation in reanalysis products. MERRA tends to overestimate the frequency at which the 99th percentile of precipitation is exceeded because this threshold tends to be lower in MERRA, making it easier to be exceeded. This feature is dominant during the summer months. MERRA tends to reproduce spatial patterns of the scale and location parameters of the generalized extreme value and generalized Pareto distributions. However, MERRA underestimates these parameters, particularly over the Gulf Coast states, leading to lower magnitudes in extreme precipitation events. Two issues in MERRA are identified: 1) MERRA shows a spurious negative trend in Nebraska and Kansas, which is most likely related to the changes in the satellite observing system over time that has apparently affected the water cycle in the central United States, and 2) the patterns of positive trend over the Gulf Coast states and along the East Coast seem to be correlated with the tropical cyclones in these regions. The analysis of the trends in the seasonal precipitation extremes indicates that the hurricane and winter seasons are contributing the most to these trend patterns in the southeastern United States. In addition, the increasing annual trend simulated by MERRA in the Gulf Coast region is due to an incorrect trend in winter precipitation extremes.

Globally estimated precipitation extremes

2020 ◽  
Author(s):  
Gaby Gründemann ◽  
Ruud van der Ent ◽  
Hylke Beck ◽  
Marc Schleiss ◽  
Enrico Zorzetto ◽  
...  
Keyword(s):  
Extreme Precipitation ◽  
Global Scale ◽  
Extreme Value ◽  
Precipitation Extremes ◽  
The Novel ◽  
Extreme Value Distributions ◽  
Extreme Precipitation Events ◽  
Return Levels ◽  
High Return ◽  
Precipitation Events

<p>Understanding the magnitude and frequency of extreme precipitation events is a core component of translating climate observations to planning and engineering design. This research aims to capture extreme precipitation return levels at the global scale. A benchmark of the current climate is created using the global Multi-Source Weighted-Ensemble Precipitation (MSWEP-V2, coverage 1979-2017 at 0.1 arc degree resolution) data, by using both classical and novel extreme value distributions. Traditional extreme value distributions, such as the Generalized Extreme Value (GEV) distribution use annual maxima to estimate precipitation extremes, whereas the novel Metastatistical Extreme Value (MEV) distribution also includes the ordinary precipitation events. Due to this inclusion the MEV is less sensitive to local extremes and thus provides a more reliable and smoothened spatial pattern. The global scale application of methods allows analysis of the complete spatial patterns of the extremes. The generated database of precipitation extremes for high return periods is particularly relevant in otherwise data-sparse regions to provide a benchmark for local engineers and planners.</p>

scholarly journals Characterisation of extreme winter precipitation in Mediterranean coastal sites and associated anomalous atmospheric circulation patterns

2010 ◽  
Vol 10 (5) ◽  
pp. 1037-1050 ◽  
Author(s):  
A. Toreti ◽  
E. Xoplaki ◽  
D. Maraun ◽  
F. G. Kuglitsch ◽  
H. Wanner ◽  
...  
Keyword(s):  
Atmospheric Circulation ◽  
Extreme Precipitation ◽  
Large Scale ◽  
Western Mediterranean ◽  
Precipitation Extremes ◽  
Return Level ◽  
Jet Stream ◽  
Eastern Basin ◽  
Extreme Precipitation Events ◽  
Precipitation Events

Abstract. We present an analysis of daily extreme precipitation events for the extended winter season (October–March) at 20 Mediterranean coastal sites covering the period 1950–2006. The heavy tailed behaviour of precipitation extremes and estimated return levels, including associated uncertainties, are derived applying a procedure based on the Generalized Pareto Distribution, in combination with recently developed methods. Precipitation extremes have an important contribution to make seasonal totals (approximately 60% for all series). Three stations (one in the western Mediterranean and the others in the eastern basin) have a 5-year return level above 100 mm, while the lowest value (estimated for two Italian series) is equal to 58 mm. As for the 50-year return level, an Italian station (Genoa) has the highest value of 264 mm, while the other values range from 82 to 200 mm. Furthermore, six series (from stations located in France, Italy, Greece, and Cyprus) show a significant negative tendency in the probability of observing an extreme event. The relationship between extreme precipitation events and the large scale atmospheric circulation at the upper, mid and low troposphere is investigated by using NCEP/NCAR reanalysis data. A 2-step classification procedure identifies three significant anomaly patterns both for the western-central and eastern part of the Mediterranean basin. In the western Mediterranean, the anomalous southwesterly surface to mid-tropospheric flow is connected with enhanced moisture transport from the Atlantic. During ≥5-year return level events, the subtropical jet stream axis is aligned with the African coastline and interacts with the eddy-driven jet stream. This is connected with enhanced large scale ascending motions, instability and leads to the development of severe precipitation events. For the eastern Mediterranean extreme precipitation events, the identified anomaly patterns suggest warm air advection connected with anomalous ascent motions and an increase of the low- to mid-tropospheric moisture. Furthermore, the jet stream position (during ≥5-year return level events) supports the eastern basin being in a divergence area, where ascent motions are favoured. Our results contribute to an improved understanding of daily precipitation extremes in the cold season and associated large scale atmospheric features.

scholarly journals Novel indices for the comparison of precipitation extremes and floods: an example from the Czech territory

2015 ◽  
Vol 19 (11) ◽  
pp. 4641-4652 ◽  
Author(s):  
M. Müller ◽  
M. Kašpar ◽  
A. Valeriánová ◽  
L. Crhová ◽  
E. Holtanová ◽  
...  
Keyword(s):  
Precipitation Extremes ◽  
Discharge Data ◽  
The Czech Republic ◽  
Extreme Precipitation Events ◽  
Precipitation Seasonality ◽  
Abnormality Index ◽  
Areal Precipitation ◽  
Precipitation Indices ◽  
Large Floods ◽  
Precipitation Events

Abstract. This paper presents three indices for evaluation of hydrometeorological extremes, considering them as areal precipitation events and trans-basin floods. In contrast to common precipitation indices, the weather extremity index (WEI) reflects not only the highest precipitation amounts at individual gauges but also the rarity of the amounts, the size of the affected area, and the duration of the event. Furthermore, the aspect of precipitation seasonality was considered when defining the weather abnormality index (WAI), which enables the detection of precipitation extremes throughout the year. The precipitation indices are complemented with the flood extremity index (FEI) employing peak discharge data. A unified design of the three indices, based on return periods of station data, enables one to compare easily inter-annual and seasonal distributions of precipitation extremes and large floods. The indices were employed in evaluation of 50 hydrometeorological extremes of each type (extreme precipitation events, seasonally abnormal precipitation events, and large floods) during the period 1961–2010 in the Czech Republic. A preliminary study of discrepancies among historic values of the indices indicated that variations in the frequency and/or magnitude of floods can generally be due not only to variations in the magnitude of precipitation events but also to variations in their seasonal distribution and other factors, primarily the antecedent saturation.

scholarly journals Projected Changes in Precipitation Extremes over Shaanxi Province, China, in the 21st Century

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Ling Li ◽  
Ziniu Xiao ◽  
Shuxiang Luo ◽  
Aili Yang
Keyword(s):  
Global Warming ◽  
21St Century ◽  
Extreme Precipitation ◽  
Climate Model ◽  
Global Climate Model ◽  
Precipitation Extremes ◽  
Shaanxi Province ◽  
Extreme Precipitation Events ◽  
The Future ◽  
Precipitation Events

Extreme precipitation events, which have intensified with global warming, will have a pernicious influence on society. It would be desirable to understand how they will evolve in the future as global warming becomes more serious with time. Thus, the primary objective of this study is to provide a comprehensive understanding of the changing characteristics of the precipitation extremes in the 21st century over Shaanxi Province, a climate-sensitive and environmentally fragile area located in the east of northwestern China, based on a consecutive simulation of the 21st century conducted by the regional climate model RegCM4 forced by the global climate model HadGEM2-ES at high resolution under middle emission scenario of the Representative Concentration Pathway 4.5 (RCP4.5). Basic validation of the model performance was carried out, and six extreme precipitation indices (EPIs) were used to assess the intensity and frequency of the extreme precipitation events over Shaanxi Province. The results show that RegCM4 reproduces the observed characteristics of extreme precipitation events over Shaanxi Province well. Overall for the domain, the EPIs excluding consecutive dry days (CDD) have a growing tendency during 1980–2098 although they exhibit spatial variability over Shaanxi Province. Some areas in the arid northern Shaanxi may have more heavy rainfalls by the middle of the 21st century but less wet extreme events by the end of the 21st century. And the humid central and southern regions would suffer more precipitation-related natural hazards in the future.

scholarly journals Evaluation of precipitation extremes and floods and comparison between their temporal distributions

2015 ◽  
Vol 12 (1) ◽  
pp. 281-310 ◽  
Author(s):  
M. Müller ◽  
M. Kašpar ◽  
A. Valeriánová ◽  
L. Crhová ◽  
E. Holtanová
Keyword(s):  
Precipitation Extremes ◽  
Precipitation Data ◽  
Hydrological Response ◽  
Spatial Averaging ◽  
Flood Events ◽  
The Czech Republic ◽  
Extreme Precipitation Events ◽  
Extreme Flood ◽  
Abnormality Index ◽  
Precipitation Events

Abstract. We proposed three analogous extremity indices based on the estimated return periods at individual sites and spatial averaging of the values; we optimized both the areal extent and the duration of individual events. The weather extremity index (WEI), the weather abnormality index (WAI), and the flood extremity index (FEI) were applied to the original precipitation data, the seasonally transformed precipitation data, and the runoff data to identify extreme precipitation events (EPEs), abnormal precipitation events (APEs), and extreme flood events (EFEs), respectively. We present 50 events of each type from the period of 1961–2010 in the Czech Republic and compare their inter-annual and seasonal distributions. Most of EFEs were produced by an EPE in warmer half-years, whereas fewer than half of the EFEs were produced by an APE in the remainders of the years because thawing can substantially enhance the discharge at those times. Most significant EPEs occurred in July and the first half of August, although their hydrological responses were also significantly influenced by the antecedent saturation and other factors. As a result, the accumulation of precipitation extremes during the 1977–1986 period produced less significant flooding than another accumulation after 1996. In general, the primary discrepancies between the magnitudes of EPEs and EFEs occurred in May and September, when consequent floods were usually much larger and smaller in relation to the WEI, respectively. The hydrological response to APEs was usually strong in December, whereas another accumulation of EFEs in March was usually not due to APEs. Neither precipitation nor flood extremes occurred from early April through early May. This study confirms that variations in the frequency and/or magnitude of floods can be due not only to variations in the magnitude of precipitation events but also to variations in their seasonal distribution and other factors, primarily the antecedent saturation. The differences could be further studied with respect to circulation conditions.

scholarly journals The RainBO Platform for Enhancing Urban Resilience to Floods: An Efficient Tool for Planning and Emergency Phases

Climate ◽  
2019 ◽  
Vol 7 (12) ◽  
pp. 145
Author(s):  
Giulia Villani ◽  
Stefania Nanni ◽  
Fausto Tomei ◽  
Stefania Pasetti ◽  
Rita Mangiaracina ◽  
...  
Keyword(s):  
Flood Risk ◽  
Extreme Precipitation ◽  
Urban Areas ◽  
Early Warning Systems ◽  
Economic Losses ◽  
Urban Resilience ◽  
Multiple Sources ◽  
Life Project ◽  
Extreme Precipitation Events ◽  
Precipitation Events

Many urban areas face an increasing flood risk, which includes the risk of flash floods. Increasing extreme precipitation events will likely lead to greater human and economic losses unless reliable and efficient early warning systems (EWS) along with other adaptation actions are put in place in urban areas. The challenge is in the integration and analysis in time and space of the environmental, meteorological, and territorial data from multiple sources needed to build up EWS able to provide efficient contribution to increase the resilience of vulnerable and exposed urban communities to flooding. Efficient EWS contribute to the preparedness phase of the disaster cycle but could also be relevant in the planning of the emergency phase. The RainBO Life project addressed this matter, focusing on the improvement of knowledge, methods, and tools for the monitoring and forecast of extreme precipitation events and the assessment of the associated flood risk for small and medium watercourses in urban areas. To put this into practice, RainBO developed a webGIS platform, which contributes to the “planning” of the management of river flood events through the use of detailed data and flood risk/vulnerability maps, and the “event management” with real-time monitoring/forecast of the events through the collection of observed data from real sensors, estimated/forecasted data from hydrologic models as well as qualitative data collected through a crowdsourcing app.

scholarly journals Assessment of GPM-Era Satellite Products’ (IMERG and GSMaP) Ability to Detect Precipitation Extremes over Mountainous Country Nepal

Atmosphere ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 254
Author(s):  
Bikash Nepal ◽  
Dibas Shrestha ◽  
Shankar Sharma ◽  
Mandira Singh Shrestha ◽  
Deepak Aryal ◽  
...  
Keyword(s):  
Extreme Precipitation ◽  
Daily Precipitation ◽  
Precipitation Amount ◽  
Probability Of Detection ◽  
Precipitation Extremes ◽  
Extreme Precipitation Events ◽  
Precipitation Measurement ◽  
Global Precipitation Measurement ◽  
Global Precipitation ◽  
Precipitation Events

The reliability of satellite precipitation products is important in climatic and hydro-meteorological studies, which is especially true in mountainous regions because of the lack of observations in these areas. Two recent satellite rainfall estimates (SREs) from Global Precipitation Measurement (GPM)-era—Integrated Multi-Satellite Retrievals for Global Precipitation Measurement (IMERG-V06) and gauge calibrated Global Satellite Mapping of Precipitation (GSMaP-V07) are evaluated for their spatiotemporal accuracy and ability to capture extreme precipitation events using 279 gauge stations from southern slope of central Himalaya, Nepal, between 2014 and 2019. The overall result suggests that both SREs can capture the spatiotemporal precipitation variability, although they both underestimated the observed precipitation amount. Between the two, the IMERG product shows a more consistent performance with a higher correlation coefficient (0.52) and smaller bias (−2.49 mm/day) than the GSMaP product. It is worth mentioning that the monthly gauge-calibrated IMERG product yields better detection capability (higher probability of detection (POD) values) of daily precipitation events than the daily gauge calibrated GSMaP product; however, they both show similar performance in terms of false alarm ratio (FAR) and critical success index (CSI). Assessment based on extreme precipitation indices revealed that the IMERG product outperforms GSMaP in capturing daily precipitation extremes (RX1Day and RX5Day). In contrast, the GSMaP product tends to be more consistent in capturing the duration and threshold-based precipitation extremes (consecutive dry days (CDD), consecutive wet days (CWD), number of heavy precipitation days (R10mm), and number of extreme precipitation days (R25mm)). Therefore, it is suggested that the IMERG product can be a good alternative for monitoring daily extremes; meanwhile, GSMaP could be a better option for duration-based extremes in the mountainous region.

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