SINGAPORE: As extreme weather events like floods ravage some parts of the world, Singapore’s weather forecasting body is continuing its work on overcoming challenges to provide better predictions.
Weather forecasting in the tropics poses a different set of challenges from forecasting in the temperate regions, the Meteorological Service Singapore (MSS), which is under the National Environment Agency (NEA), told CNA in response to queries related to extreme weather events.
“Weather systems in temperate regions are typically longer-lived, larger in scale, and better simulated by weather prediction models. In contrast, thunderstorms which commonly affect Singapore are relatively small-scale and tend to develop and dissipate quickly,” said an NEA spokesperson.
Experts also told CNA that with Singapore's built-up landscape, it is not easy to make accurate weather forecasts.
“The urban (setting) disturbs the wind flows and the urban (setting) releases the heat absorbed, changing the flow patterns. So it's extremely difficult to make predictions about precipitation and flooding in an urban setting,” said Assistant Professor Wang Jingyu from the National Institute of Education, whose research interests include regional and global climate modelling and applications and severe convective storms and hazards.
There is a need to collaborate with other countries to build a more advanced weather forecasting system, he said.
On its part, the MSS is developing an urban-scale weather model, a complex computer program which simulates the behaviour of atmospheric processes over Singapore and may more accurately predict weather conditions.
Data collected by sensors around the island will be used to evaluate the accuracy of this model.
MSS, through its Centre for Climate Research Singapore (CCRS), is also actively conducting research to improve the capabilities of its high-resolution weather prediction model to better simulate how Sumatra squalls - an organised line of thunderstorms - and monsoon surges form and develop in the surrounding region.
The research also involves ingesting more meteorological observations into the model to forecast such events up to two days ahead.
Currently, MSS issues warnings of heavy rain up to 30 minutes in advance for localised thunderstorms which occur frequently year-round and can occasionally trigger flash floods.
For large-scale systems that bring prolonged rain, such as the monsoon surge events which normally occur from December to January, MSS issues an advisory on prolonged heavy rain up to a few days ahead.
“Extreme weather events are, however, more challenging to forecast,” the spokesperson said.
PREPARING FOR EXTREME WEATHER EVENTS
Extreme weather events are becoming more frequent due to global warming, said Asst Prof Wang.
While events like severe floods used to take place once every 50 to 100 years, they will take place once every 10 years in the middle of the century and could become an annual event by the end of the century, he said.
Singapore, too, is at risk.
The country should relook at the design of the building and the infrastructure, because they were designed for a once-in-50-year or once-in-100-years flooding, said Asst Prof Wang.
This is something in the process with the set-up of the Coastal Protection and Flood Resilience Institute (CFI) Singapore, said Professor Vladan Babovic from the Civil and Environmental Engineering Department at the National University of Singapore (NUS).
The institute, which will bring together expertise from local universities, research institutes and industry players, is looking at how rainfall will change in the next 100 years, “so that we know this is what to expect and how our infrastructure should be reinforced and additionally protected”, he said.
While today’s infrastructure can withstand severe flooding, there is a need to understand how the climate will change this in the future, he said.
“If we don't start doing something about this today, it’ll be too late. We have to start adapting to these things,” said Prof Babovic.
“One degree (Celsius) of temperature increase provides the ability for the atmosphere to store 7.5 per cent extra humidity. So if you have 7.5 per cent more water in the air, that water that sits in the air will eventually condense and come back in rainfall,” he said.
"We also have urban heat. So if Singapore gets warmer, hotter, this means that the atmosphere can store more heat with more vapour in the atmosphere, more water, which actually means we will have more extreme rainfall as well,” he added.
Experts are exploring solutions that can ease floods in urban areas, such as nature-inspired spaces that are engineered to help with the weather, Prof Babovic said.
Public education is also key so that everyone knows what to do in the event of extreme weather, said Asst Prof Wang.
“We should conduct public awareness campaigns and educational programmes to inform residents about flooding risk, safety matters and how to respond to the alerts. Educate and prepare the citizens so they can take proactive steps to protect themselves and help others."
The public may also subscribe to the Public Utilities Board's SMS service or Telegram channel, which sends alerts in the event of heavy rain or high water levels.
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