Assessing the impact of internal climate variability and anthropogenic climate change on hydrometeorological extremes in the Mun River Basin, Thailand | |
| Author | Fernando, Warnakulasooriya Neelappage Shanali Minoshi |
| Call Number | AIT Thesis no.WM-21-02 |
| Subject(s) | Climatic changes--Thailand--Mun River Basin Hydrometeorology--Thailand--Mun River Basin Land use--Cambodia--Siem Reap |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering in Water Engineering and Management |
| Publisher | Asian Institute of Technology |
| Abstract | Climate change is one of the greatest threats to global security. Climate change is basically attributed to anthropogenic forcing resulting in anthropogenic climate change (ACC), internal climate variability (ICV) and external climate variability. Since external processes affects climate on either short-term temporal scale or much longer temporal scale, external climate variability is not considered in climate studies. Moreover, phenomenon of climate change is most likely to alter hydro-meteorology and the extremes. Therefore, the study focuses on the assessment of contribution ICV and ACC on hydro-meteorological extremes. The study brings forth estimation of the signal to noise ratio (SNR) and the timing of ACC emergence from ICV for hydrometeorological impact studies based on climate model ensembles. Specifically, ICV is defined as the inter-member difference in a multi-member ensemble of a climate model in which anthropogenic climate trends have been removed through detrending. ACC is defined as the mean of multi model ensembles. The signal to noise ratio is the ratio between ACC and ICV. The intersection between ACC and ICV curves is defined as the time of emergence of ACC from ICV. The study results interpret that the temperature change has already been dominated by ACC by the end of large century. However, the rainfall change will be disguised by ICV up to the first half of this century. Yet, the time of emergence of streamflow occurs a few decades later than that of rainfall by the combined influence of rainfall and temperature. Moreover, temperature extremes are identified to have a higher impact from ACC than rainfall complying with contribution estimated for the mean state. Yet, higher contribution of ACC is observed in maximum extremes in temperature than minimums. Contribution of ACC is found to be significant for low flow duration than high flow duration. Conversely, ACC is found to be more prominent with high flow frequency than low flow frequency. The results imply that adapting to ICV would be the most efficient approach in the near future, but in the long-term future, more attention should be vested on ACC. |
| Year | 2021 |
| 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;Shanmugam, Mohana Sundaram |
| Scholarship Donor(s) | His Majesty the King's Scholarships (Thailand) |
| Degree | Thesis (M. Eng.) - Asian Institute of Technology, 2021 |