Author(s): Shie-Yui Liong; San Chuin Liew; Srivatsan V. Raghavan
Linked Author(s):
Keywords: Climate Change; Reanalyses data; Regional Climate Model; Ungauged sites; IDF curves
Abstract: The impact of a c hanging cl imate is already being felt on several hydrological systems both on a r egional and s ub-regional s cale o f t he g lobe. Southeast Asia i s o ne of th e r egions s trongly a ffected b y c limate change. W ith cl imate c hange, o ne o f t he a nticipated i mpacts i s a n i ncrease i n the i ntensity an d frequency of extreme rainfall which further increase the region’s flood catastrophes, human casualties and economic l oss. . O ptimal mitigation measures ca n b e t aken o nly when s tormwater s ystems ar e d esigned using rainfall Intensity-Duration-Frequency (IDF) curves derived from a long and good quality rainfall data. Developing IDF curves for the future climate can be even more challenging especially for ungauged sites. The cu rrent p ractice t o d erive cu rrent cl imate’s IDF c urves f or ungauge sites is, f or e xample, to ‘borrow’ or ‘interpolate’ data from regions of climatologically similar characteristics. Liew e t a l. (2013) presented a n ovel approach to derive IDF curves for p resent cl imate in which rainfall data were ex tracted from a h igh spatial resolution Regional Climate Model (RCM; 30 × 30 km over the study domain) d riven by E RA-40 d ataset. T his approach was demonstrated o n a n ungauged s ite (Java, I ndonesia) an d t he results are quite promising. In t his p aper, t he a uthors extend the ap plication o f the ap proach to o ther ungauged s ites particularly in Peninsular Malaysia. The s tudy is p erformed b y first i dentifying th e n earest meteorological s tations where IDF curves e xist. Biases resulting from these meteorological s ites are cap tured and serve as very useful i nformation i n t he d erivation o f p resent d ay I DF c urves f or un gauged sites. T he p resent d ay climate’s derived IDF cu rves at th e ungauged s ites fall within th e s uggested b ias c orrection range. T his range allows designers to decide on a value within the lower and upper bounds, normally subjected to engineering, eco nomic, s ocial a nd e nvironmental c oncerns. It a lso pr ovides policy makers b etter information on t he a dequacy of s torm dr ainage d esign, f or t he cu rrent cl imate at t he u ngauged s ites, a nd the adequacy of the existing storm drainage to cope the impacts of climate change.
Year: 2013