Rainfall analysis of the Kelantan big yellow flood 2014

摘要

In December 2014, Kelantan was hit by the worst flood ever recorded. Did the rainfall exceed historical records, how rare are they and what causes them? This paper answers these questions. Estimation of the return periods uses the GEV distribution model and stations with more than 25 years records. Spatial distribution plots of the cumulated rainfall depths were constructed using IDW interpolation method. Four major outcomes are: 1) Spatial rainfall patterns show high amounts of rainfall accumulated by phases (Phase 1- daily rainfall up to 300 mm; Phase 2- daily rainfall up to 500 mm); 2) record breaking rainfall events occurred at 9 stations significantly at Gunung Gagau (1598.9 mm compared to 976.5 mm 7-day cumulated rainfall). Many stations upstream of the river basin experienced ARIs near and over 100 years and several experienced more than 200 years; and 4) Enhanced rainfall were experienced due to the combined effect of the monsoon season, Madden Julian Oscillation and temperature below anomalies at the Siberian High.