Assessment of future variability in extreme precipitation and the potential effects on the wadi flow regime

Luminda Niroshana Gunawardhana, Ghazi A. Al-Rawas, So Kazama, Khalid A. Al-Najar

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3 Citations (Scopus)

Abstract

The objective of this study is to investigate how the magnitude and occurrence of extreme precipitation events are affected by climate change and to predict the subsequent impacts on the wadi flow regime in the Al-Khod catchment area, Muscat, Oman. The tank model, a lumped-parameter rainfall-runoff model, was used to simulate the wadi flow. Precipitation extremes and their potential future changes were predicted using six-member ensembles of general circulation models (GCMs) from the Coupled Model Intercomparison Project Phase 5 (CMIP5). Yearly maxima of the daily precipitation and wadi flow for varying return periods were compared for observed and projected data by fitting the generalized extreme value (GEV) distribution function. Flow duration curves (FDC) were developed and compared for the observed and projected wadi flows. The results indicate that extreme precipitation events consistently increase by the middle of the twenty-first century for all return periods (49–52 %), but changes may become more profound by the end of the twenty-first century (81–101 %). Consequently, the relative change in extreme wadi flow is greater than twofolds for all of the return periods in the late twenty-first century compared to the relative changes that occur in the mid-century period. Precipitation analysis further suggests that greater than 50 % of the precipitation may be associated with extreme events in the future. The FDC analysis reveals that changes in low-to-moderate flows (Q60–Q90) may not be statistically significant, whereas increases in high flows (Q5) are statistically robust (20 and 25 % for the mid- and late-century periods, respectively).

Original languageEnglish
Article number626
JournalEnvironmental Monitoring and Assessment
Volume187
Issue number10
DOIs
Publication statusPublished - Oct 22 2015

Fingerprint

twenty first century
return period
Precipitation (meteorology)
Runoff
Climate change
Catchments
Distribution functions
Rain
effect
extreme event
general circulation model
runoff
rainfall
climate change
analysis

Keywords

  • Climate change
  • Frequency analysis
  • Oman
  • Weather generator

ASJC Scopus subject areas

  • Environmental Science(all)
  • Management, Monitoring, Policy and Law
  • Pollution

Cite this

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abstract = "The objective of this study is to investigate how the magnitude and occurrence of extreme precipitation events are affected by climate change and to predict the subsequent impacts on the wadi flow regime in the Al-Khod catchment area, Muscat, Oman. The tank model, a lumped-parameter rainfall-runoff model, was used to simulate the wadi flow. Precipitation extremes and their potential future changes were predicted using six-member ensembles of general circulation models (GCMs) from the Coupled Model Intercomparison Project Phase 5 (CMIP5). Yearly maxima of the daily precipitation and wadi flow for varying return periods were compared for observed and projected data by fitting the generalized extreme value (GEV) distribution function. Flow duration curves (FDC) were developed and compared for the observed and projected wadi flows. The results indicate that extreme precipitation events consistently increase by the middle of the twenty-first century for all return periods (49–52 {\%}), but changes may become more profound by the end of the twenty-first century (81–101 {\%}). Consequently, the relative change in extreme wadi flow is greater than twofolds for all of the return periods in the late twenty-first century compared to the relative changes that occur in the mid-century period. Precipitation analysis further suggests that greater than 50 {\%} of the precipitation may be associated with extreme events in the future. The FDC analysis reveals that changes in low-to-moderate flows (Q60–Q90) may not be statistically significant, whereas increases in high flows (Q5) are statistically robust (20 and 25 {\%} for the mid- and late-century periods, respectively).",
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AU - Kazama, So

AU - Al-Najar, Khalid A.

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N2 - The objective of this study is to investigate how the magnitude and occurrence of extreme precipitation events are affected by climate change and to predict the subsequent impacts on the wadi flow regime in the Al-Khod catchment area, Muscat, Oman. The tank model, a lumped-parameter rainfall-runoff model, was used to simulate the wadi flow. Precipitation extremes and their potential future changes were predicted using six-member ensembles of general circulation models (GCMs) from the Coupled Model Intercomparison Project Phase 5 (CMIP5). Yearly maxima of the daily precipitation and wadi flow for varying return periods were compared for observed and projected data by fitting the generalized extreme value (GEV) distribution function. Flow duration curves (FDC) were developed and compared for the observed and projected wadi flows. The results indicate that extreme precipitation events consistently increase by the middle of the twenty-first century for all return periods (49–52 %), but changes may become more profound by the end of the twenty-first century (81–101 %). Consequently, the relative change in extreme wadi flow is greater than twofolds for all of the return periods in the late twenty-first century compared to the relative changes that occur in the mid-century period. Precipitation analysis further suggests that greater than 50 % of the precipitation may be associated with extreme events in the future. The FDC analysis reveals that changes in low-to-moderate flows (Q60–Q90) may not be statistically significant, whereas increases in high flows (Q5) are statistically robust (20 and 25 % for the mid- and late-century periods, respectively).

AB - The objective of this study is to investigate how the magnitude and occurrence of extreme precipitation events are affected by climate change and to predict the subsequent impacts on the wadi flow regime in the Al-Khod catchment area, Muscat, Oman. The tank model, a lumped-parameter rainfall-runoff model, was used to simulate the wadi flow. Precipitation extremes and their potential future changes were predicted using six-member ensembles of general circulation models (GCMs) from the Coupled Model Intercomparison Project Phase 5 (CMIP5). Yearly maxima of the daily precipitation and wadi flow for varying return periods were compared for observed and projected data by fitting the generalized extreme value (GEV) distribution function. Flow duration curves (FDC) were developed and compared for the observed and projected wadi flows. The results indicate that extreme precipitation events consistently increase by the middle of the twenty-first century for all return periods (49–52 %), but changes may become more profound by the end of the twenty-first century (81–101 %). Consequently, the relative change in extreme wadi flow is greater than twofolds for all of the return periods in the late twenty-first century compared to the relative changes that occur in the mid-century period. Precipitation analysis further suggests that greater than 50 % of the precipitation may be associated with extreme events in the future. The FDC analysis reveals that changes in low-to-moderate flows (Q60–Q90) may not be statistically significant, whereas increases in high flows (Q5) are statistically robust (20 and 25 % for the mid- and late-century periods, respectively).

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