Author(s): Narongrit Luangdilok; Watin Thanathanphon; Piyamarn Sisomphon; Siriluk Chumchean; Sudajai Lowanichchai
Linked Author(s):
Keywords: Rainfall estimation; Radar; Telemetric; Thailand
Abstract: Rainfall is one of the most important factors for water management in Thailand. Telemetric rain gauges are most widely used in rainfall measurement. However, the density of the telemetric network is usually unable to capture all heavy rainfall events in some areas, especially the mountain areas. Fortunately, the weather radar can be an alternative data source to fulfill the requirements for monitoring and warning system. Its wider coverage compared to interpolation of point data and the high resolution on both spatial and temporal are key advantages that enable the use of weather radar in flood operation and management. This study aimed to develop an operational rainfall estimation using a real-time combination of weather radar and rain gauge data. First, the general Z-R relationship (Z=aR") is developed using the observed hourly rainfall data and reflectivity data from weather radar which cover the central part of Thailand. The developed equation can produce a better result than the default equation from the instrument with 4.612 and 4.805 of RMSE respectively. However, the result of evaluation also shows obviously that the radar rainfall is affected by uncertainty errors. These errors should be reduced to make the higher reliability of radar rainfall. Therefore, in this study, there is an attempt to remove the bias of radar rainfall using the Inverse Distance Weight methods. Finally, the results of the developed system are integrated and displayed on the decision support system which shows rainfall map and warning information in sufficient lead time.
Year: 2018