scholarly journals On the Flood Peak Distributions over China

2019 ◽  
Author(s):  
Long Yang ◽  
Lachun Wang ◽  
Xiang Li ◽  
Jie Gao
Keyword(s):  
Tropical Cyclones ◽  
Southern China ◽  
Flood Hazard ◽  
Critical Role ◽  
Northern China ◽  
Drainage Area ◽  
Flood Hazards ◽  
Flood Peak ◽  
Flood Peaks ◽  
Landfalling Tropical Cyclones

Abstract. Time series of annual maximum instantaneous peak discharge from 1120 stations with record lengths of at least 50 years are used to examine flood peak distributions across China. Abrupt change rather than slowly varying trend is the dominant mode of the violation of stationary assumption for annual flood peaks over China. The dominance of decreasing trends in annual flood peak series indicates a weakening tendency of flood hazard over China in recent decades. Delayed (advanced) occurrence of annual flood peaks in southern (northern) China point to a tendency for seasonal clustering of floods across the entire country. We model the upper tails of flood peaks based on the Generalized Extreme Value (GEV) distributions for the stationary series, and evaluate the scale-dependent properties of flood peaks. The relations of GEV parameters and drainage area show spatial contrasts between northern and southern China. Weak dependence of the GEV shape parameter on drainage area highlights the critical role of space-time rainfall organizations in dictating the upper tails of flood peaks. Landfalling tropical cyclones play an important role in characterizing the upper-tail properties of flood peak distributions especially in northern China and southeastern coast, while the upper tails of flood peaks are dominated by extreme monsoon rainfall in southern China. Severe flood hazards associated with landfalling tropical cyclones are characterized with tropical cyclones experiencing extratropical transition, and persistent moisture transport/interactions with regional topography as demonstrated by Typhoon Nina (1975).

scholarly journals On the flood peak distributions over China

2019 ◽  
Vol 23 (12) ◽  
pp. 5133-5149 ◽  
Author(s):  
Long Yang ◽  
Lachun Wang ◽  
Xiang Li ◽  
Jie Gao
Keyword(s):  
Tropical Cyclones ◽  
Extreme Values ◽  
Southern China ◽  
Northern China ◽  
Global Scale ◽  
Flood Hazards ◽  
Flood Peak ◽  
Complex Interactions ◽  
Flood Peaks ◽  
Landfalling Tropical Cyclones

Abstract. Here we for the first time present a nationwide characterization of flood hazards across China. Our analysis is based on an exceptional dataset of 1120 stream gauging stations with continuous records of annual flood peaks for at least 50 years across the entire country. Our results are organized by centering on various aspects of flood peak distributions, including temporal changes in flood series and their spatial variations, the statistical distribution of extreme values, and the properties of storms that lead to annual flood peaks. These aspects altogether contribute to an improved understanding of flood hydrology under a changing environment over China and promote advances in flood science at the global scale. Historical changes in annual flood peaks demonstrate frequent abrupt changes rather than slowly varying trends. The dominance of decreasing annual flood peak magnitudes indicates a weakening tendency of flood hazards over China in recent decades. We model the upper tails of flood peaks based on the generalized extreme value (GEV) distributions. The GEV shape parameter is weakly dependent on drainage area, but it shows spatial splits tied to rainfall climatology between northern and southern China. Landfalling tropical cyclones play an important role in characterizing the upper-tail properties of flood peak distributions especially in northern China and southeastern coast, while the upper tails of flood peaks are dominated by extreme monsoon rainfall in southern China. Severe flood hazards associated with landfalling tropical cyclones are characterized by complex interactions of storm circulations with synoptic environments (i.e., mid-latitude baroclinic disturbances) and regional topography.

scholarly journals Distribution of Flood Risk Area in Bodri Watershed of Kendal Regency

2021 ◽  
Vol 6 (2) ◽  
pp. 59-69
Author(s):  
Husna Fauzia ◽  
◽  
Eka Cahyaningsih ◽  
Hery Hariyanto ◽  
Satya Nugraha ◽  
...  
Keyword(s):  
Land Use ◽  
Spatial Modeling ◽  
Flood Risk ◽  
Flood Hazard ◽  
Risk Level ◽  
Flood Hazards ◽  
Risk Area ◽  
Flood Peak ◽  
Risk Levels ◽  
Central Java

Flooding is a catastrophic phenomenon that can occur due to various factors, such as uncontrolled landuse changes, climate change, and weather anomalies, and drainage infrastructure damage. The Bodri watershed in Kendal Regency is one of the watersheds in Central Java, which is categorized as critical based on Decree No.328/Menhut-II/2009. Some of the problems in the Bodri watershed include land use that is not suitable for its designation, flooding, erosion, and landslides. This study aims to conduct spatial modeling to create flood hazard maps and flood risk level maps in the Bodri watershed. The method used is hydrograph analysis, flood modeling, potential flood hazards, and flood risk levels. Analysis of the potential for flood hazards from the spatial modeling inundation map with the input of the flood peak return period of 2 years (Q2), 5 years (Q5), and 50 years (Q50). Vulnerability analysis based on land use maps of flood hazard areas. The distribution of flood-prone areas in the Bodri watershed is in Pidodo Kulon Village, Pidodo Wetan Village, and Bangunsari Village.

scholarly journals Analysis and Projection of Flood Hazards over China

Water ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 1022 ◽  
Author(s):  
Yulian Liang ◽  
Yongli Wang ◽  
Yinjun Zhao ◽  
Yuan Lu ◽  
Xiaoying Liu
Keyword(s):  
21St Century ◽  
Flood Control ◽  
Climate Model ◽  
Southern China ◽  
Flood Hazard ◽  
Global Climate ◽  
Global Climate Model ◽  
Flood Hazards ◽  
Rcp Scenarios ◽  
Meteorological Observations

Floods have been experienced with greater frequency and more severity under global climate change. To understand the flood hazard and its variation in the future, the current and future flood hazards in the 21st century in China are discussed. Floods and their trends are assessed using the accumulation precipitation during heavy rainfall process (AP_HRP), which are calculated based on historical meteorological observations and the outputs of a global climate model (GCM) under three Representative Concentration Pathway (RCP) scenarios. The flood-causing HRPs counted by the flood-causing critical precipitation (the 60% fractile of AP_HRP) capture more than 70% of historical flood events. The projection results indicate that the flood hazards could increase under RCP4.5 and RCP8.5 and increase slightly under RCP2.6 during the 21st century (2011–2099). The spatial characteristics of flood hazards and their increasing trends under the three RCPs are similar in most areas of China. More floods could occur in southern China, including Guangdong, Hainan, Guangxi and Fujian provinces, which could become more serious in southeastern China and the northern Yunnan province. Construction of water conservancy projects, reservoir dredging, improvement of drainage and irrigation equipment and enhancement of flood control and storage capacity can mitigate the impacts of floods and waterlogging on agriculture.

scholarly journals Spatial Characterization of Flood Magnitudes over the Drainage Network of the Delaware River Basin

2017 ◽  
Vol 18 (4) ◽  
pp. 957-976 ◽  
Author(s):  
Ping Lu ◽  
James A. Smith ◽  
Ning Lin
Keyword(s):  
United States ◽  
Tropical Cyclones ◽  
River Basin ◽  
Hydrologic Model ◽  
Drainage Network ◽  
Eastern United States ◽  
Delaware River ◽  
Flood Peak ◽  
Landfalling Tropical Cyclones ◽  
Flood Index

Abstract A framework to characterize the distribution of flood magnitudes over large river networks is developed using the Delaware River basin in the northeastern United States as a principal study region. Flood magnitudes are characterized by the flood index, which is defined as the ratio of the flood peak for a flood event to the historical 10-yr flood magnitude. Event flood peaks are computed continuously over the drainage network using a distributed hydrologic model, CUENCAS, with high-resolution radar rainfall fields as the principal forcing. The historical 10-yr flood is calculated based on scaling relationships between the 10-yr flood and drainage area. Summary statistics for characterizing the probability distribution and spatial correlation of flood magnitudes over the drainage network are developed based on the flood index. This framework is applied to four flood events in the Delaware River basin that reflect the principal flood-generating mechanisms in the eastern United States: landfalling tropical cyclones (Hurricane Ivan in September 2004 and Hurricane Irene in August 2011), late winter/early spring extratropical systems (April 2005), and warm season convective systems (June 2006). The framework can be utilized to characterize the spatial distribution of floods, most notably for floods caused by landfalling tropical cyclones, which play an important role in controlling the upper tail of flood peak magnitudes over much of the eastern United States.

scholarly journals Topographic Dependence of Cropland Transformation in China during the First Decade of the 21st Century

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Yuejiao Li ◽  
Xiaohuan Yang ◽  
Wenli Long
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
21St Century ◽  
Land Reclamation ◽  
Southern China ◽  
Critical Role ◽  
Northern China ◽  
Limiting Factor ◽  
Spatial Statistical Analysis ◽  
Level Of Economic Development

Terrain plays a critical role in the selection of cropland. As a physical and geographical element of the landscape, terrain is an important limiting factor in land use change and has a strong influence on human activities. The objectives of this study are to investigate the topographic characteristics of cropland-related transformations in China during the first decade of the 21st century and to explore the implications of land use change as it relates to securing a national food supply. A 2010 satellite-based land use dataset and the DEM data were used to conduct spatial statistical analysis using altitude, slope, and fragmentation data. The results showed the following. (1) As the urbanization and industrialization of China occur, and China attempts to replace this occupied cropland with newly reclaimed cropland, the topography of the most recently reclaimed cropland has been more poorly suited to farming than the topography of the occupied cropland it replaces in most provinces. (2) The area of occupied cropland was much larger than of those reclaimed; the qualities of occupied and reclaimed cropland were significantly different. (3) Land reclamation mainly occurred in northern China, instead of in southern China, which has a higher level of economic development. Our findings imply that the potential area available for cropland production may be limited.

scholarly journals ADVANCES AND ISSUES IN UNCERTAINTY QUANTIFICATION FOR COASTAL FLOOD HAZARDS

2018 ◽  
pp. 19
Author(s):  
Taylor G. Asher ◽  
Jennifer L. Irish ◽  
Donald T. Resio
Keyword(s):  
Tropical Cyclones ◽  
Historical Data ◽  
Flood Hazard ◽  
Joint Probability ◽  
Joint Probability Distribution ◽  
Probability Method ◽  
Flood Hazards ◽  
Significant Cost ◽  
Flooding Risk ◽  
Flood Elevation

Probabilistic flood hazard assessments have advanced substantially, with modern methods for dealing with the risk from tropical cyclones utilizing either a variation of the joint probability method with optimal sampling (JPM-OS)2,3 or the statistical deterministic track method (SDTM)1,4. In the JPM-OS, tropical cyclones are reduced to a set of 5 to 9 parameters, whose characteristics are analyzed statistically to develop a joint probability distribution for tropical cyclones of given characteristics. In the SDTM, cyclogenesis of a large number of storms is seeded via a statistical model from historical data, then storms are propagated using one of several different methods, incorporating varying degrees of the physics of cyclone transformation as the storms propagate. Due to the significant cost of storm surge simulations, some form of optimization or selection is then performed to reduce the number of synthetic storms that must be simulated to determine the flood elevation corresponding to a given recurrence interval (e.g. the so-called 100-year flood). In both methods, substantial uncertainties exist, which have a tendency to increase the estimated flooding risk. Efforts to account for these uncertainties have varied, and there remains significant work to be done. Here, we demonstrate how these uncertainties tend to increase the flood risk and show that additional sources of uncertainty remain to be accounted for.

Tropical cyclone flooding in the Carolinas

2021 ◽  
Author(s):  
Maofeng Liu ◽  
James A. Smith ◽  
Long Yang ◽  
Gabriel A. Vecchi
Keyword(s):  
Tropical Cyclone ◽  
Dominant Role ◽  
Critical Role ◽  
Extreme Rainfall ◽  
Water Vapor Transport ◽  
Flood Peak ◽  
Physical Mechanisms ◽  
Orographic Enhancement ◽  
Flood Peaks

Abstract The climatology of tropical cyclone flooding in the Carolinas is analyzed through annual flood peak observations from 411 U.S. Geological Survey (USGS) stream gaging stations. Tropical cyclones (TCs) account for 28% of the top ten annual flood peaks, 55% of record floods, and 91% of floods with peak magnitudes at least five times greater than the 10-year floods, highlighting the prominent role of TCs for flood extremes in the Carolinas. Of all TC-related flood events, the top ten storms account for nearly 1/3 of annual flood peaks and more than 2/3 of record floods, reflecting the dominant role of a small number of storms in determining the upper tail of flood peak distributions. Analyses of the ten storms highlight both common elements and diversity in storm properties that are responsible for flood peaks. Extratropical transition and orographic enhancement are important elements of extreme TC flooding in the Carolinas. Analyses of the Great Flood of 1916 highlight the flood peak of 3115 m3 s−1 in French Broad River at Asheville, 2.6 times greater than the second-largest peak from a record of 124 years. We also examine the hydroclimatology, hydrometeorology and hydrology of flooding from Hurricanes Matthew (2016) and Florence (2018). Results point to contrasting storm properties for the two events, including tracks as well as rainfall distribution and associated physical mechanisms. Climatological analyses of vertically integrated water vapor transport (IVT) highlight the critical role of anomalous moisture transport from the Atlantic Ocean in producing extreme rainfall and flooding over the Carolinas.

scholarly journals Impact of Different Types of ENSO Years on Intensity Changes of Landfalling Tropical Cyclones over China

Atmosphere ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 161
Author(s):  
Lu Liu
Keyword(s):  
Tropical Cyclones ◽  
South China ◽  
Southern China ◽  
Eastern China ◽  
Broad Band ◽  
Relative Vorticity ◽  
Central Pacific ◽  
Translation Speed ◽  
Easterly Wind ◽  
Landfalling Tropical Cyclones

This study examines whether there are significant differences in intensity and destructiveness of landfalling tropical cyclones (TCs) over China in central Pacific warm (CPW), eastern Pacific warm (EPW) and La Niña (LA) years. By analyzing different seasons and locations of TCs making landfall over China, it was found that TCs in LA years generally had a larger power dissipation index (PDI) and may cause more disasters in China, while TCs in EPW years had a larger PDI over South China in autumn. A larger PDI of TCSC (landing location in Southern China) usually occurred in EPW years and a larger PDI of TCEC (landing location in Eastern China) occurred in LA years, compared with CPW years. The TCs in LA years were generally stronger, more frequent, and of longer duration over China, because of the positive relative humidity (RH) anomalies, the significant anomalous cyclone that occupied the South China Sea (SCS), and the easterly wind anomalies providing a beneficial steering flow for TCs making landfall. In EPW years, although TCs were less frequent, they had stronger intensity when making landfall and a longer lifetime over land which was mainly caused by a broad band of anomalous westerlies over the SCS giving rise to a belt of positive relative vorticity anomalies, as well as the slow translation speed of TCs before landfall supplying more energy for TCs to survive over land. Overall, we conclude that greater caution is warranted when TCs occur in LA and EPW years, as they may result in more serious disasters in China.

scholarly journals Mixture Distributions and the Hydroclimatology of Extreme Rainfall and Flooding in the Eastern United States

2011 ◽  
Vol 12 (2) ◽  
pp. 294-309 ◽  
Author(s):  
James A. Smith ◽  
Gabriele Villarini ◽  
Mary Lynn Baeck
Keyword(s):  
United States ◽  
Tropical Cyclones ◽  
Regional Climate ◽  
Daily Rainfall ◽  
Extreme Rainfall ◽  
Flood Frequency ◽  
Eastern United States ◽  
Flood Peak ◽  
Storm Evolution ◽  
Landfalling Tropical Cyclones

Abstract Flooding in the eastern United States reflects a mixture of flood-generating mechanisms, with landfalling tropical cyclones and extratropical systems playing central roles. The authors examine the climatology of heavy rainfall and flood magnitudes for the eastern United States through analyses of long-duration records of flood peaks and maximum daily rainfall series. Spatial heterogeneities in flood peak distributions due to orographic precipitation mechanisms in mountainous terrain, coastal circulations near land–ocean boundaries, and urbanization impacts on regional climate are central elements of flood peak distributions. Lagrangian analyses of rainfall distribution and storm evolution are presented for flood events in the eastern United States and used to motivate new directions for stochastic modeling of rainfall. Tropical cyclones are an important element of the upper tail of flood peak distributions throughout the eastern United States, but their relative importance varies widely, and abruptly, in space over the region. Nonstationarities and long-term persistence of flood peak and rainfall distributions are examined from the perspective of the impacts of human-induced climate change on flood-generating mechanisms. Analyses of flood frequency for the eastern United States, which are based on observations from a dense network of U.S. Geological Survey (USGS) stream gauging stations, provide insights into emerging problems in flood science.

scholarly journals Characteristics of Flood Flow with Active Sediment Transport in the Sozu River Flood Hazards at the Severe Rainfall Event in July 2018

2019 ◽  
Vol 14 (6) ◽  
pp. 886-893
Author(s):  
Daisuke Harada ◽  
◽  
Naoko Nagumo ◽  
Yousuke Nakamura ◽  
Shinji Egashira
Keyword(s):  
Sediment Transport ◽  
Flow Characteristics ◽  
Alluvial Fan ◽  
Flood Hazards ◽  
Field Surveys ◽  
Flood Peak ◽  
River Flood ◽  
Flood Peaks ◽  
Flood Flow ◽  
Second Peak

This study reveals the characteristics of flood flow with active sediment transport that caused the Sozu River flood disaster in July 2018. The results of field surveys revealed that the basin contains steep mountains and flat areas, facilitating the rapid transport of sediment produced in the mountains to downstream areas during the disaster. Two-dimensional numerical simulations of flood flow with sediment transport are conducted to realize the flood flow characteristics. As a result of the simulation, a huge amount of sediment deposition in the channel near the top of the alluvial fan increases the inundation damage at downstream areas. The results indicate that within two flood peaks during the disaster, the inundation in the second flood peak is more severe than that in the first peak, whereas the discharge of the second peak is much less than that in the first peak, caused by the reduction in the capacity of the original channel owing to the sand deposition during the first and second flood peaks.

Sign in / Sign up

Export Citation Format

Share Document