scholarly journals Review: Can temperature be used to inform changes to flood extremes with global warming?

2021 ◽  
Vol 379 (2195) ◽  
pp. 20190551 ◽  
Author(s):  
Conrad Wasko
Keyword(s):  
Extreme Precipitation ◽  
Water Resource Management ◽  
Flash Flood ◽  
Historical Trends ◽  
Precipitation Temperature ◽  
Antecedent Conditions ◽  
Infrastructure Design ◽  
Transfer Of Information ◽  
Hydrologic Extremes ◽  
Good Agreement

As climate change alters flood risk, there is a need to project changes in flooding for water resource management, infrastructure design and planning. The use of observed temperature relationships for informing changes in hydrologic extremes takes many forms, from simple proportional change approaches to conditioning stochastic rainfall generation on observed temperatures. Although generally focused on understanding changes to precipitation, there is an implied transfer of information gained from precipitation-temperature sensitivities to flooding as extreme precipitation is often responsible for flooding. While reviews of precipitation-temperature sensitivities and the non-stationarity of flooding exist, little attention has been given to the intersection of these two topics. Models which use temperature as a covariate to assess the non-stationarity of extreme precipitation outperform both stationary models and those using a temporal trend as a covariate. But care must be taken when projecting changes in flooding on the basis on precipitation-temperature sensitivities, as antecedent conditions modify the runoff response. Although good agreement is found between peak flow-temperature sensitivities and historical trends across Australia, there remains little evaluation of flood projections using temperature sensitivities globally. Significant work needs to be done before the use of temperature as a covariate for flood projection can be adopted with confidence. This article is part of a discussion meeting issue ‘Intensification of short-duration rainfall extremes and implications for flash flood risks’.

scholarly journals Resolving Inconsistencies in Extreme Precipitation‐Temperature Sensitivities

2020 ◽  
Vol 47 (18) ◽  
Author(s):  
J. B. Visser ◽  
C. Wasko ◽  
A. Sharma ◽  
R. Nathan
Keyword(s):  
Extreme Precipitation ◽  
Precipitation Temperature

scholarly journals Future changes in atmospheric rivers and extreme precipitation in Norway

2020 ◽  
Author(s):  
Kirien Whan ◽  
Jana Sillmann ◽  
Nathalie Schaller ◽  
Rein Haarsma
Keyword(s):  
Extreme Precipitation ◽  
Water Resource Management ◽  
Extreme Event ◽  
Freezing Point ◽  
Global Climate Model ◽  
Extreme Value Analysis ◽  
Value Analysis ◽  
Atmospheric Rivers ◽  
Extreme Precipitation Events ◽  
The Future

<p>Atmospheric rivers (AR) are associated with flooding events in Norway, like the flood that impacted Flåm in 2014. We assess trends in Norwegian AR characteristics, and the influence of AR variability on extreme precipitation in Norway. After evaluating the global climate model, EC-Earth, compared to the ERA-Interim reanalysis, we show that ARs increase in both intensity and frequency by the end of the century. In two regions on the west coast, the majority of winter precipitation maxima are associated with AR events (> 80% of cases). A non-stationary extreme value analysis indicates that the magnitude of extreme precipitation events in these regions is associated with AR intensity. Indeed, the 1-in-20 year extreme event is 17% larger when the AR-intensity is high, compared to when it is low. Finally, we find that the region mean temperature during winter AR events increases in the future. In the future, when the climate is generally warmer, AR days will tend to make landfall when the temperature is above the freezing point. The partitioning of more precipitation as rain, rather than snow, can have severe impacts on flooding and water resource management in Norway.</p>

scholarly journals Estimation of flash flood hazard in the Pidima-Arfara area (Messinia, SW Greece), based on the study of instantaneous unitary hydrographs, longitudinal profilesand stream power

2007 ◽  
Vol 40 (4) ◽  
pp. 1621
Author(s):  
E. Sambaziotis ◽  
I. Fountoulis
Keyword(s):  
Flash Flood ◽  
Flood Hazard ◽  
Flash Floods ◽  
Topographic Map ◽  
Stream Power ◽  
Longitudinal Gradient ◽  
Hydrological Simulation ◽  
Small Catchment ◽  
Map Scale ◽  
Good Agreement

In this paper it is an effort to combine different methodologies in order to locate the sensitive sites in flash flood phenomena in a relatively small catchment located north of Kalamata (Messinia SW Péloponnèse, Greece). Based on digitised topographic map (scale 1/5.000) the longitudinal, gradient and stream power profiles of the watercourses were constructed and the results (possibly sensitive to flash floods sites) were compared to ones that came from applying hydrological simulation, hydrographs as well as Instantaneous Unitary Hydrographs. The comparison showed that the results were in good agreement.

A relation between extreme precipitation and surface air temperature over Russia in the last four decades

2021 ◽  
Author(s):  
Maria Aleshina ◽  
Vladimir Semenov ◽  
Alexander Chernokulsky
Keyword(s):  
Relative Humidity ◽  
Air Temperature ◽  
Extreme Precipitation ◽  
Surface Air Temperature ◽  
Precipitation Extremes ◽  
Convective Precipitation ◽  
Temperature Range ◽  
Precipitation Temperature ◽  
Moisture Availability ◽  
Precipitation And Temperature

<p>Precipitation extremes are widely thought to intensify with the global warming due to exponential growth, following the Clausius-Clapeyron (C-C) equation of atmosphere water holding capacity with rising temperatures. However, a number of recent studies based on station and reanalysis data for the contemporary period showed that scaling rates between extreme precipitation and temperature are strongly dependent on temperature range, region and moisture availability. Here, we examine the scaling between daily precipitation extremes and surface air temperature over Russian territory for the last four decades using meteorological stations data and ERA-Interim reanalysis. The precipitation-temperature relation is examined for total precipitation amount and, separately, for convective and large-scale precipitation types. In winter, a general increase of extreme precipitation of all types according to C-C relation is revealed. For the Russian Far East region, the stratiform precipitation extremes scale with surface air temperature following even super C-C rates, about two times as fast as C-C. However, in summer we find a peak-like structure of the precipitation-temperature scaling, especially for the convective precipitation in the southern regions of the country. Being consistent with the C-C relationship, extreme precipitation peaks at the temperature range between 15 °C and 20 °C. For the higher temperatures, the negative scaling prevails. Furthermore, it was shown that relative humidity in general decreases with growing temperature in summer. Notably, there appears to be a temperature threshold in the 15-20 °C range, beyond that relative humidity begins to decline more rapidly. This indicates that moisture availability can be the major factor for the peak-shaped relationship between extreme precipitation and temperature revealed by our analysis.</p>

Simulating extreme precipitation over the Arabian Peninsula using a convective-permitting sub-seasonal reforecast product

2020 ◽  
Author(s):  
Thang M. Luong ◽  
Christoforus Bayu Risanto ◽  
Hsin-I Chang ◽  
Hari Prasad Dasari ◽  
Raju Attada ◽  
...  
Keyword(s):  
Extreme Events ◽  
Extreme Precipitation ◽  
Arabian Peninsula ◽  
Flash Flood ◽  
Value Added ◽  
Rain Gauge ◽  
Potential Predictability ◽  
Extreme Precipitation Events ◽  
Simulated Precipitation ◽  
Precipitation Events

<p>Despite being one of the driest places in the world, the Arabian Peninsula (AP) occasionally experiences extreme precipitation events associated with organized convections. On 25 November 2009, for instance, a cutoff low driven rainfall exceeding 140 mm over a 6-hour period triggered a flash flood event in Jeddah, Saudi Arabia, claiming hundreds of lives and substantially damaging infrastructure. Similar extreme precipitation events have occurred in subsequent years. To assess the potential predictability of extreme precipitation in the Arabian Peninsula, we perform retrospective forecast simulations for several extreme events occurring over the period 2000 to 2018, out to a sub-seasonal timescale (3-4 weeks). Using the Advanced Research version of Weather Research and Forecasting Model (WRF-ARW), we dynamically downscale 11 ensemble members of the European Centre for Medium-Range Weather Forecasts (ECMWF) sub-seasonal reforecasts at convective-permitting resolution (4 km). WRF simulated precipitation is evaluated against various precipitation products, including the Global Precipitation Measurement (GPM) system, Climate Prediction Center morphing technique (CMORPH), and the Saudi Ministry of Water and Electricity(MOWE) and the Presidency of Meteorology and Environment(PME) regional rain gauge measurements. The convective-permitting WRF simulations substantially improve the representation of precipitation relative to the ECMWF reforecast, in terms of spatial distribution and timing. A specific focus in the presentation of the results will be on the potential value added by the use of convective-permitting modeling (CPM) to forecasting extreme events at sub-seasonal timescales. The predictability of the synoptic pattern could be the key for CPM sub-seasonal-type forecast for the AP.</p>

scholarly journals An Analysis of Precipitation Extreme Events Based on the SPI and EDI Values in the Free State Province, South Africa

Water ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 3058
Author(s):  
Omolola M. Adeola ◽  
Muthoni Masinde ◽  
Joel O. Botai ◽  
Abiodun M. Adeola ◽  
Christina M. Botai
Keyword(s):  
South Africa ◽  
Extreme Precipitation ◽  
Water Resource Management ◽  
Early Warning Systems ◽  
Generalized Extreme Value Distribution ◽  
Free State ◽  
Annual Rainfall ◽  
Return Periods ◽  
Free State Province ◽  
Return Levels

Recognizing that, over the last several years, extreme rainfall has led to hazardous stress in humans, animals, plants, and even infrastructure, in the present study, we aimed to investigate the characteristics of droughts over the Free State (FS) Province of South Africa in order to determine the future likelihood of reoccurrences of precipitation extremes using the generalized extreme value distribution (GEV) and extreme frequency analysis (EFA). In this regard, daily rainfall datasets from nine South African weather service homogenous climatic districts, spanning from 1980 to 2019, were used to compute: (a) the total annual rainfall, (b) the Effective Drought Index (EDI), and (c) the Standard Precipitation Index (SPI). The SPI was calculated for 3, 6, and 12 month accumulation periods (hereafter SPI-3, SPI-6, and SPI-12, respectively). The trend analysis results of the EDI and SPI-3, -6, and -12 showed that the Free State Province is generally negative, illustrating persistent drought. An analysis of the GEV parameters across the EDI and SPI-3, -6, and -12 values illustrated that the location, scale, and shape parameters exhibited a noticeable spatial variability across the Free State Province with the location parameter largely negative, the scale parameter largely positive, while the shape parameter pointed to an inherent Type III (Weibull) GEV distribution. In addition, the return levels for the drought/wet duration and severity of the EDI and SPI-3, -6, and -12 values generally showed increasing patterns across the corresponding return periods; the spatial contrasts were only noticeable in the return levels derived from the wet/drought duration and severity derived from SPI-3, -6, and -12 values (and not in the EDI). Further, the EFA results pointed to a noticeable spatial contrast in the return periods derived from the EDI and SPI-3, -6, and -12 values for each of the extreme precipitation categories: moderately wet, severely wet, extremely wet to moderately dry, and severely dry. Over four decades, the FS Province has generally experienced a suite of extreme precipitation categories ranging from moderately wet, severely wet, extremely wet to moderately dry, severely dry, and extremely dry conditions. Overall, the present study contributes towards implementation of effective drought early warning systems and can be used to enhance drought related policy and decision making in support of water resource management and planning in the FS Province.

scholarly journals Spatiotemporal variation characteristics of extreme precipitation in the upper reaches of the Hongshui River Basin during 1959–2016

2021 ◽  
Author(s):  
Ya Huang ◽  
Ling Yi ◽  
Weihua Xiao ◽  
Guibing Hou ◽  
Yuyan Zhou
Keyword(s):  
River Basin ◽  
Extreme Precipitation ◽  
Water Resource Management ◽  
Flood Control ◽  
Southern Oscillation ◽  
Disaster Mitigation ◽  
Eastern Region ◽  
Extreme Precipitation Indices ◽  
Precipitation Indices ◽  
Precipitation Events

Abstract Understanding changes in the intensity and frequency of extreme precipitation is vital for flood control, disaster mitigation, and water resource management. In this study, 12 extreme precipitation indices and the best-fitting extreme value distribution were used to analyze the spatiotemporal characteristics of extreme precipitation in the upper reaches of the Hongshui River Basin (UHRB). The possible links between extreme precipitation and large-scale circulation were also investigated. Most extreme precipitation indices increased from west to east in the UHRB, indicating that the eastern region is a humid area with abundant precipitation. The indices for consecutive wet days (CWD) and precipitation events (R0.1) decreased significantly, indicating that the UHRB tends to be dry, with few precipitation events. The probability distribution functions of most extreme precipitation indices, especially that of R0.1, shifted significantly to the left in 1988–2016 compared with 1959–1987, further indicating that the UHRB has experienced a significant drying trend in recent decades. The East Asian summer monsoon and the El Niño–Southern Oscillation/Pacific Decadal Oscillation were confirmed to influence extreme precipitation in the UHRB. These findings are helpful for understanding extreme precipitation variation trends in the UHRB and provide references for further research.

scholarly journals More frequent flash flood events and extreme precipitation favouring atmospheric conditions in temperate regions of Europe

2021 ◽  
Author(s):  
Judith Meyer ◽  
Malte Neuper ◽  
Luca Mathias ◽  
Erwin Zehe ◽  
Laurent Pfister
Keyword(s):  
Extreme Precipitation ◽  
Western Europe ◽  
Flash Flood ◽  
Flash Floods ◽  
Water Levels ◽  
Specific Humidity ◽  
Atmospheric Conditions ◽  
Flood Events ◽  
Extreme Precipitation Events ◽  
Precipitation Events

Abstract. In recent years, flash floods repeatedly occurred in temperate regions of central western Europe. Unlike in Mediterranean catchments, this flooding behaviour is unusual. In the past, and especially in the 1990s, floods were characterized by predictable, slowly rising water levels during winter and driven by westerly atmospheric fluxes (Pfister et al., 2004). The intention of this study is to link the recent occurrence of flash floods in central western Europe to extreme precipitation and specific atmospheric conditions to identify the cause for this apparent shift. Therefore, we hypothesise that an increase in extreme precipitation events has subsequently led to an increase in the occurrence of flash flood events in central western Europe and all that being caused by a change in the occurrence of flash flood favouring atmospheric conditions. To test this hypothesis, we compiled data on flash floods in central western Europe and selected precipitation events above 40 mm h−1 from radar data (RADOLAN, DWD). Moreover, we identified proxy parameters representative for flash flood favouring atmospheric conditions from the ERA5 reanalysis dataset. High specific humidity in the lower troposphere (q ≥ 0.004 kg kg−1), sufficient latent instability (CAPE ≥ 100 J kg−1) and weak deep-layer wind shear (DLS ≤ 10 m s−1) proved to be characteristic for long-lasting intense rainfall that can potentially trigger flash floods. These atmospheric parameters, as well as the flash flood and precipitation events were then analysed using linear models. Thereby we found significant increases in atmospheric moisture contents and increases in atmospheric instability. Parameters representing the motion and organisation of convective systems occurred slightly more often or remained unchanged in the time period from 1981–2020. Moreover, a trend in the occurrence of flash floods was confirmed. The number of precipitation events, their maximum 5-minute intensities as well as their hourly sums were however characterized by large inter-annual variations and no trends could be identified between 2002–2020. This study therefore shows that the link from atmospheric conditions via precipitation to flash floods cannot be traced down in an isolated way. The complexity of interactions is likely higher and future analyses should include other potentially relevant factors such as intra-annual precipitation patterns or catchment specific parameters.

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