| Author | Sujittra Charoenhirunyingyos |
| Call Number | AIT Diss. no.RS-09-06 |
| Subject(s) | Soil moisture--Remote sensing
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| Note | A dissertation submitted for the partial fulfillment of the requirements for the degree of Doctor of Technical Science |
| Publisher | Asian Institute of Technology |
| Series Statement | Dissertation ; no. RS-09-06 |
| Abstract | Soil hydraulic parameters are essential input for s imulating soil water and solute movements. However, it is not feasible to describe the spatial distributions of these parameters by field and laboratory testing, as they are both expensive and time consuming. Remote Sensing (RS) can be applied here, as it provides useful informat ion over large areas. Even though soil hydraulic parameters cannot be seen directly in RS images, using the SWAP-GA data assimilation scheme, the unseen parameters can be o btained from RS data. The SWAP (Soil- Water-Atmosphere-Plant) agro-hydrological model is coupled with genetic algorithm (GA), resulting in SWAP-GA to estimate the soil hydraulic parameters. A multi-criteria objective function was proposed in this study to incorporate more information into the assimilation process for a better chance for finding acceptable model parameters. The objective function was formulated as equally weighted combinations of different inputs. Data assimilation using multi-criteria functions has been applied to estima te soil hydraulic parameters in the root zone area at four different soil depths (3 cm, 12 c m, 28 cm and 60 cm). The reference inputs used in the assimilation process are: i) LAI (Leaf Area Index) retrieved from MODIS satellit e imagery, ii) ET a (Actual Evapotranspiration) derived from SEBAL (Su rface Energy Balance Algorithm for Land), and iii) SM (Soil Moisture) from ground measurement. Soil moisture from ground measurement was added int o the process to determine how much it can improve the model performance, considering s oil moisture sensor was easier measurement and cheaper price recently compared to laboratory soil sample testing. The reference inputs are individually and jointly teste d. The result of simulated soil moisture was validated with observed SM in the field. When using only satellite reference data in the assimilation process, the results showed a good mat ch up to the depth of 28 cm. It was found that the simulation was satisfactory enhanced up to the depth of 60 cm when using additional soil moisture from ground measurement with satellit e data in the assimilation process, the combinations of SM and LAI showed a good result of soil moisture simulation. The result of rice yield simulation showed around 2% of deviation from the actual harvested yield when using soil hydraulic parameters from satellite LAI. Meanwhile, deployment of soil moisture sensors was improved the simulated result with less than 1% dissimilar to the actual yield. Soil moisture and yield were simulated under dry sp ell scenarios to identify the influential period of dry spell that have a critical impact on rice yield. The simulated soil moisture under dry spell scenarios showed the largest impact found at 12 cm (the difference of simulated soil moisture with and without rain was 0 .17 cm 3 cm -3 ), while the fewer impact was seen at 60 cm soil depth (the difference of sim ulated soil moisture with and without rain was 0.04 cm 3 cm -3 ). The results of rice yield simulation was reveale d that dry spell in October especially in the first half month will be caused the most critical damage on rice. In addition, the simulation was suggested that the optimum period of transplanting is around 1 to 3 weeks earlier than the actual transpl anting date. |
| Year | 2009 |
| Corresponding Series Added Entry | Asian Institute of Technology. Dissertation ; no. RS-09-06 |
| Type | Dissertation |
| School | School of Engineering and Technology (SET) |
| Department | Department of Information and Communications Technologies (DICT) |
| Academic Program/FoS | Remote Sensing (RS) |
| Chairperson(s) | Tripathi, Nitin Kumar |
| Examination Committee(s) | Surat Lertlum ;Babel, Mukand Singh ;Somchai Baimoung |
| Scholarship Donor(s) | Government of Thailand |
| Degree | Thesis (Ph.D.) - Asian Institute of Technology, 2009 |