Application of radar-rainfall for inflow estimation to Kaeng Krachan Reservoir, Thailand | |
| Author | Arisara Nakburee |
| Call Number | AIT Thesis no.WM-18-19 |
| Subject(s) | Radar--Thailand--Kaeng Krachan Reservoir Rain and rainfall--Thailand--Kaeng Krachan Reservoir |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Water Engineering & Management, School of Engineering & Technology |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. WM-18-19 |
| Abstract | Rainfall measurement data is an important input for water resource management, hydrological and climatic modelling. Traditional method like rain gauge measurement may provide inaccurate quality and quantity rainfall data due to inadequate or no rain gauge network. Estimation of rainfall and runoff in ungauged basins is major challenge due to the absent of rainfall and streamflow gauges. Technology of remote sensing which has high spatial coverage was examined to be used to address data lacking problems. Weather radar which has high spatial and temporal resolutions and a large areal coverage, compared to rain gauge network, is being studied to improve its quality in this area. The objectives of present study are to assess radar estimated rainfall conversion relationship and evaluate the applicability of radar rainfall to simulate runoff in ungauged basin. Kaeng Krachan Dam in Phetchaburi province at the western part of Thailand is selected as a study area. Radar reflectivity from S-band doppler radar at Sattahip, Chonburi province under Department of Royal Rainmaking and Agricultural Aviation operation is collected and converted into cartesian coordinate to match with Department of Royal Rainmaking and Agricultural Aviation and Hydro and Agro Informatics Institute’s rain gauge locations. Daily, hourly and 6-minute temporal resolutions and three vertical level measured radar reflectivity are paired with rainfall data in 2015-2017 wet season to establish empirical Z-R relationship. The best fit Z-R relationship in this study, ??=??????????.??, is verified using previous research of Z-R relationship in the same radar range and standard Z-R relationship of summer convective cloud. The verification results show that rainfall conversion from newly establish Z-R is different from previous study 20% and 8% from standard relationship which is in the acceptable range. Subsequently, new Z-R is used to convert radar reflectivity to rainfall in the study area with four spatial resolution of 25kmx25km, 17kmx17km, 9kmx9km and 6kmx6km. Four resolution rainfall data are used as input to calibrate and simulate inflow into Kaeng Krachan Dam by semi-distributed hydrological model HEC-HMS. Rainfall data from TRMM satellite as gridded rainfall data with 25kmx25km resolutions is also applied as an input to HEC-HMS model for comparison. Model performance evaluation statistics of NSE and R2 are calculated to evaluate calibration and simulation results. Radar spatial resolution of 6kmx6km has the best calibration result in NSE and R2, whereas radar spatial resolution of 9kmx9km provides quite similar performance with 6kmx6km. |
| Year | 2018 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. WM-18-19 |
| Type | Thesis |
| School | School of Engineering and Technology (SET) |
| Department | Department of Civil and Infrastucture Engineering (DCIE) |
| Academic Program/FoS | Water Engineering and Management (WM) |
| Chairperson(s) | Babel, Mukand S. ; |
| Examination Committee(s) | Shrestha, Sangam;Sarawut Ninsawat;Thanapon Piman; |
| Scholarship Donor(s) | Ministry of Agriculture and Cooperatives (MOAC), Thailand;AIT Fellowship; |