Photochemical modeling for simulation of ground-level ozone over the continental Southeast Asian Region to assess potential impacts on rice crop | |
| Author | Le Hoang Nghiem |
| Call Number | AIT Diss. no.EV-08-1 |
| Subject(s) | Photochemical smog--Southeast Asia Plants--Effect of photochemical smog on--Southeast Asia Ozone--Physiological effect--Southeast Asia Plants--Effect ofozone on--Southeast Asia |
| Note | A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Engineering in Environmental Engineering and Management |
| Publisher | Asian Institute of Technology |
| Series Statement | Dissertation ; no. EV-08-1 |
| Abstract | This research evaluates the performance of MM5-CMAQ model system in simulating the regional distribution of tropospheric ozone over the Continental South East Asian (CSEA) domain covering Thailand, Myanmar, Cambodia, Lao and Vietnam). The modelled ozone values are used to estimate AOT40 and M7 which are further used to assess the potential impacts of ozone on agricultural crops with a particular focus on the rice crop in Thailand, where high ground ozone levels are observed. The hourly emission data is prepared based on the available annual average data which is projected for the simulation year using the regional economical growth. A Fortran program is developed which successfully reads the hourly input data in the Excel format and writes in the NETcdf required by CMAQ model. The performance of the MM5-CMAQ model system in hindcast was evaluated using two historical high ozone episodes: i) January 2629, 2004 (January episode) and ii) March 24-26, 2004 (March episode). These episodes represent the typical meteorological conditions for high hourly ozone concentrations over the domain. The model outputs were compared with the available observed hourly 03 data from 23 stations in Thailand and Vietnam which shows a satisfactory agreement of the model system meeting all the US EPA performance statistics. The model system was also used for a test forecast of the next day peak ozone for the Central region of Thailand (CENTHAI) during January 2006 (30 days). The model system was able to achieve accuracy (A) level (the percentage of forecasts that correctly predict an exceedance or non-exceedance) more than 90%, which is the minimum requirement by US EPA for the initial implementation of the Air Quality Forecasting Capacity. The MM5-CMAQ system was applied to estimate surface ozone concentrations during a high ozone season (November 2003 to April 20004) to develop AOT40 maps for CSEA. Risk of the ozone effects to the common crops was assessed using the AOT40 which is calculated over a 3 month growing season. The AOT40 calculated using modelled values also agree with those based on monitoring results that are available from 26 monitoring sites for the 5-year period 2001-2005 in Thailand. There are strong seasonal variations in AOT40 with minimum values occur during July to September. The maximum values occur from December to April of the following year, which often exceed the WHO critical level of 3,000 ppbh at monitoring stations in Thailand. Highest potential risk of 0₃ effects on agricultural crops were observed in Thailand with the maximum AOT40 values of around 10,000 - 14.000 ppbh over the central region of Thailand. Further, M7 is calculated from modelled ozone values to assess the effects on rice crop, (the major crop and moderately sensitive to ozone) in Thailand. This preliminary assessment shows that high ozone levels at present are can affect grain yield for the second rice crop in Thailand which grows during the months of high ozone. The production loss of this crop in Thailand in 2003-2004 is estimated at 54,000 tones, corresponding to a national average relative yield loss (RYL) of 0.84 % |
| Year | 2008 |
| Corresponding Series Added Entry | Asian Institute of Technology. Dissertation ; no. EV-08-1 |
| Type | Dissertation |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Energy and Climate Change (Former title: Department of Energy, Environment, and Climate Change (DEECC)) |
| Academic Program/FoS | Environmental Engineering (EV) |
| Chairperson(s) | Nguyen Thi Kim Oanh |
| Examination Committee(s) | Chongrak Polprasert ;Athapol Noomhorm ;Supat Wangwongwatana |
| Scholarship Donor(s) | Danish Government funded scholarship |
| Degree | Thesis (Ph.D.) - Asian Institute of Technology, 2008 |