AI SearchApplication of weather radar for rainfall forecasting in Bangkok
Call Number: AIT Thesis no.WM-08-20 Material type:
SeriesSeries: Asian Institute of Technology. Thesis ; no. WM-08-20Publication details: Pathum Thani, Thailand : Asian Institute of Technology, 2009 Description: 197 leaves : illSubject(s): Online resources: Dissertation note: Thesis (M.Eng.) - Asian Institute of Technology, 2008 Summary: Weather radar is one of equipments that can provide real time meteorological data such as rainfall covering large area including big city like Bangkok. A lot of activities in the capital of Thailand depend on the rainfall information in advance. Although, it is difficult to understand rainfall behavior exactly, forecasting can give important information on the trends. The input data from radar images influence in forecasting processes; thus, calibration of radar is necessary and it can provide rainfall intensity (R) from output of radar, reflectivity (Z) values. The objectives of present study are to: calibrate equation of Z-R in the weather radar at Suvarnabhumi, forecast rainfall and develop a procedure to forecast rainfall at a specific location. Radar images from Suvarnbhumi radar covering Bangkok area are used in this study. The Window Correlation Matching Method (WCMM) is used to determine Z-R relationship and it takes into account the wind effecting to rain measurement and the average reflectivity of different number of pixels in radar image. Thirty six rainfall events with 117 radar images and more than 4 hours of rainfall duration of each event in 2007 and 2008 are used for weather radar calibration and rainfall forecasting. Two radar range 60 kilometers and 240 kilometers are obtained from Thai Meteorological Department (TMD). Twenty raingauge stations are used for calibration. There are nine different cases of WCMM considering time and window space to find the optimal constant values from calibration. In this study, the calibration of radar from Z-R relationship is obtained with fairly satisfactory values for Z = 44.15R¹·⁰¹⁴ for 60 kilometers radar range and poorly satisfied values for Z = 76.45R⁰·²²² with 240 kilometers radar range. Critical Success Index (CSI) is found to be 65 % when translation model is developed to forecast five minute time interval of rainfall over all selected fifteen areas in Bangkok such as Siam Paragon, Sukhumvit and Silom. The present study proposed forecasting algorithm which can provide information of rainfall direction, time of rainfall start and rainfall stop. The new indicator, Critical Success Index by Time (CSIT) has been introduced to determine the accuracy of forecast at a particular location. The forecasted result shows that CSIT is about 67% on average
| Cover image | Item type | Current library | Home library | Collection | Shelving location | Call number | Materials specified | Vol info | URL | Copy number | Status | Notes | Date due | Barcode | Item holds | Item hold queue priority | Course reserves | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
22-AIT Thesis (Replacement)
|
Asian Institute of Technology Library AIT Publications | AIT Thesis no.WM-08-20 (Browse shelf(Opens below)) | 3 | Available | 30050120690291 | |||||||||||||
40-Archives
|
Asian Institute of Technology Library Archives | AIT Thesis no.WM-08-20 (Browse shelf(Opens below)) | Available | 30050120233068 |
A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering in Water Engineering and Management
Thesis (M.Eng.) - Asian Institute of Technology, 2008
Weather radar is one of equipments that can provide real time meteorological data such as rainfall covering large area including big city like Bangkok. A lot of activities in the capital of Thailand depend on the rainfall information in advance. Although, it is difficult to understand rainfall behavior exactly, forecasting can give important information on the trends. The input data from radar images influence in forecasting processes; thus, calibration of radar is necessary and it can provide rainfall intensity (R) from output of radar, reflectivity (Z) values. The objectives of present study are to: calibrate equation of Z-R in the weather radar at Suvarnabhumi, forecast rainfall and develop a procedure to forecast rainfall at a specific location. Radar images from Suvarnbhumi radar covering Bangkok area are used in this study. The Window Correlation Matching Method (WCMM) is used to determine Z-R relationship and it takes into account the wind effecting to rain measurement and the average reflectivity of different number of pixels in radar image. Thirty six rainfall events with 117 radar images and more than 4 hours of rainfall duration of each event in 2007 and 2008 are used for weather radar calibration and rainfall forecasting. Two radar range 60 kilometers and 240 kilometers are obtained from Thai Meteorological Department (TMD). Twenty raingauge stations are used for calibration. There are nine different cases of WCMM considering time and window space to find the optimal constant values from calibration. In this study, the calibration of radar from Z-R relationship is obtained with fairly satisfactory values for Z = 44.15R¹·⁰¹⁴ for 60 kilometers radar range and poorly satisfied values for Z = 76.45R⁰·²²² with 240 kilometers radar range. Critical Success Index (CSI) is found to be 65 % when translation model is developed to forecast five minute time interval of rainfall over all selected fifteen areas in Bangkok such as Siam Paragon, Sukhumvit and Silom. The present study proposed forecasting algorithm which can provide information of rainfall direction, time of rainfall start and rainfall stop. The new indicator, Critical Success Index by Time (CSIT) has been introduced to determine the accuracy of forecast at a particular location. The forecasted result shows that CSIT is about 67% on average
There are no comments on this title.