Estimating daily evapotranspiration at field scales using metric and temporal fusion algorithms in Thailand | |
| Author | Jaraspong Ruangekavit |
| Call Number | AIT Thesis no.WM-24-01 |
| Subject(s) | Evapotranspiration--Thailand Water-supply--Thailand--Management Image processing--Data processing |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Water Engineering and Management, School of Engineering and Technology |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis; no. WM-24-01 |
| Abstract | This study employs Landsat and MODIS data fused using temporal image fusion algorithms to evaluate daily evapotranspiration (ET) at field spatiotemporal scales. The fusion of images with high temporal resolution but low spatial resolution with high spatial resolution but low temporal resolution images is especially useful when cloud cover or other factors impede the creation of high-resolution images. Furthermore, daily ET at field dimensions is evaluated utilizing the METRIC (Mapping Evapotranspiration at high Resolution with Internalized Calibration) method. The study, which was carried out in Thailand's Northern, Western, and Northeast regions between 2001 and 2004 and 2010 in an effort to enhance irrigation water management and crop water usage, employs fusion algorithms to estimate ET at field scales. In-situ FLUXTOWER data provides validation support. The METRIC algorithm, implemented in R programming, involves selecting hot and cold pixels, calculating the evapotranspiration fraction, and calculating the converging image. Additionally, the image fusion algorithm involves linear interpolation to determine daily ET and calculate daily ET from fractional evapotranspiration functions and land surface temperature. Analysis of daily ET in the Sakaerat area, with January showing the highest average daily ET values (3.5-7 mm/day) and April showing the lowest values (0-3 mm/day). In the Mae Klong area, December shows the highest average daily ET values (5-7 mm/day), and April shows the lowest values (0-1.75 mm/day). Moreover, In the Tak area, January shows the highest average daily ET values (1.5-2 mm/day), and April shows the lowest values (0-0.5 mm/day). The evapotranspiration value fluctuates with the season based on the levels of rainfall and humidity. Validation of METRIC ET using FLUXTOWER data shows satisfactory model performance. The root mean square error (RMSE) ranges from 1.3 mm/day to 2.8 mm/day for the linear interpolation. The RMSE values of the fractional evapotranspiration function and land surface temperature ranged from 1.3 mm/day to 3.5 mm/day.In conclusion, image fusion techniques provide another way to enhance ET estimation by integrating data from various sensors, including high-resolution Landsat and low-resolution MODIS imagery. This integration enhances the precision and comprehensiveness of ET data, thereby improving water resource management and agricultural planning. The study contributes to a deeper understanding of water resource utilization in Northern, Western, and Northeast Thailand, aiding informed decision making for enhancing agricultural productivity and water management practices in the region. Accurate and contemporary ET data availability can significantly enhance agricultural practices' efficiency and sustainability in the area. |
| Year | 2024 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis; no. WM-24-01 |
| Type | Thesis |
| School | School of Engineering and Technology |
| Department | Department of Civil and Infrastucture Engineering (DCIE) |
| Academic Program/FoS | Water Engineering and Management (WM) |
| Chairperson(s) | Shanmugam, Mohana Sundaram; |
| Examination Committee(s) | Natthachet Tangdamrongsub;Sarawut Ninsawat;Shrestha, Sangam; |
| Scholarship Donor(s) | Royal Thai Government Fellowship; |
| Degree | Thesis (M. Sc.) - Asian Institute of Technology, 2024 |