Impact of climate change on extreme rainfall and drainage design (Project B1.3)

Overview

In the study of climate change, rainfall projections on the time scale of minutes are of particular interest to Singapore’s Public Utilities Board (PUB) to support its climate change adaptation plans for drainage infrastructure. However, due to limitations in the global scale general circulation models (GCMs) and regional climate models (RCMs), rainfall projections for Singapore at such high temporal resolution are not readily available.

This project attempts to fill this gap via an innovative weather regime-dependent stochastic model. The model has the potential to be adopted as a tool by the National Environment Agency-Centre for Climate Research Singapore (NEA-CCRS ) to conduct high resolution regional modelling for future climate projection works.

The objectives of the project are to:

• identify the key weather regimes in Singapore; and
• downscale climate projections from GCM/RCM to produce future rainfall projections that are of sufficiently high resolution to allow for accurate modelling and generate flood maps.

Key outcomes

The project involves the identification of key weather regimes in Singapore, with data being compared to climate projections being developed by the NEA-CCRS to generate rainfall projections on a small scale. The data produced will also help determine the likely shift in Intensity-Duration- Frequency (IDF) curves for future time periods.

The rainfall projections and changes in short-duration rainfall intensities can be used by PUB to generate flood maps so as to study the adequacy of drainage infrastructure in coping with changes in rainfall due to climate change.