Applications and Methods for Extreme Rainfall Analysis

Applications Baseline and total seasonal and monthly changes in slow onset for water resources planning Extreme changes, changes in return period, IDF*, or DDF* for water infrastructure design Extreme changes in short duration (hourly), changes in return period, IDF, or DDF for urban water infrastructure design Water resources, flooding, inundation modelling Extreme changes in short duration (hourly), changes in return period, IDF, or DDF for urban water infrastructure design
Precipitation related climate change analysis type Annual or monthly mean Daily precipitation extremes Subdaily to multiple Intensity Duration Function(IDF), or Density Duration Function (DDF) Hydrological model input data Very high resolution RCM precipitation changes for urban water systems
Recommended methodology Change factor approach (Percentage change per degree, or percentage in different scenarios) Generalized Extreme Value analysis, multiple distributions fitting testing. Generalized Extreme Value analysis and IDF curve fitting, multiple distributions fitting testing. Bias correction statistical downscaled with climate change projection 1-3 km resolution convection permitting RCM simulations
Historical data required Observation based Monthly historical data Daily observation time series Subdaily observation data Subdaily or daily observation Sub-hourly precipitation observation
GCM/RCM data required Multiple GCM and RCM monthly mean ensemble results Multiple GCM daily precipitation based extreme value change patterns Multiple GCM** 3 hourly precipitation output extreme value change patterns Multiple sources: subdaily or daily GCM or RCM** RCM sub-hourly data
CLIMsystems tool SimCLIM monthly pattern scenario generator SimCLIM GEV tool and in-house tools Subdaily extreme event analysis in-house tool Multiple GCM daily BCSD*** dataset WRF specific domain case by case
Potential linkage to other models WEAP, DSSAT Related infrastructure design models Related infrastructure design models SWAT, DHI, EWater, HECS, SWMM, Flood Modeller SWAT, DHI, EWater, HECS, SWMM, other Related infrastructure design models

*IDF and DDF = Intensity Duration Frequency and Depth Duration Frequency commonly used for water drainage system design.
**GCM = General Circulation Model; RCM= Regional Climate Model
***BCSD = Bias Correction Spatial Disaggregation