The development of tropical flood estimation technique derived from weather radar information

Abstract

Floods are among the most frequent and costliest natural disasters. Conditions that cause floods include heavy or long-steady rain for several hours or days that saturates the ground. Since the long term precipitation forecast is still not reliable enough, an accurate estimates degree of the extremity for upcoming flood events that might cause dangerous meteorological situations is required. The information from a rain gauge and radar data could be useful for decision maker as an additional information for flood warning system.The main objective is to develop incorporating an algorithm that processes inputs namely the rainfall rate information, horizontal and vertical profile of radar reflectivity values. The rainfall rate data, cloud thickness values, and the sizes of the clouds during the 2014 flood disaster were acquired and analyzed.This algorithm was developed to estimate flood phenomenon derived from rain gauges and weather radar. The rainfall rate, cloud thickness value, the size of the cloud during the flood disaster was measured. In this research the rain gauge data and radar data on the duration of time over the flood area covered by meteorological radar and rain gauge was analyzed. The specific time can be the whole duration for the rain event before, during and after the flood tragedy. The procedure was applied to 14 days precipitation phenomenon observed in Kota Bharu, Kelantan (Malaysia) from 13 December 2014 until 26 December 2014 and was validate using the precipitation phenomenon observed in Kuantan, Pahang (Malaysia) during the extreme flood tragedy in December 2013. The algorithm indicate the binary value between positive values or zero either negative values which indicates the characteristics of the cloud and rainfall rate that can cause flooding. If the value is 1 or more it means the cloud characteristic and rainfall rate during that specific time may cause flooding to happen. While for value 0 or less, it indicates that the cloud characteristic and rainfall rate is in a secure condition. The derived algorithm acquired in this research is very useful to forecast the flood tragedy in the future and as a development model to be integrated into the radar system.