| Summary: | 碩士 === 大漢技術學院 === 土木工程與環境資源管理研究所 === 107 === Abstract
This research uses precipitation data from Hualien’s Air Quality Monitoring Station. It does not take into account the data gathered during typhoons as well as any invalid data. It also uses trajectory maps of reverse flowing air currents. It uses classifications according to the World Meteorological Organization’s (WMO’s) precipitation scale, as well as interval classification of pH values. This research discovers that the frequency of Hualien’s acidic rainfall precipitation as well as trends in its pH value change according to where the air currents originate from. The results of the research are as follows:
Irrespective of origin of air current, the average precipitation is 518 hours per year, with a 62% chance of acid rain. There is an average of 33 hours of heavy rainfall per year, with a 60% chance of acid rain. There is an average of 97 hours of medium rainfall per year, with a 58% chance of acid rain. There is an average of 388 hours of light rainfall per year, with a 63% chance of acid rain.
The northeastern monsoon winds bring an average rainfall of 277 hours per year, a 54% probability of rain. It brings an average of 11 hours of heavy rainfall per year, with a 69% probability of acid rain. It brings an average of 44 hours of medium rainfall per year, with a 69% probability of acid rain. It brings an average of 222 hours of light rainfall per year, with a 71% probability of acid rain.
The high pressure reflow an average rainfall of 130 hours per year, a 26% possibility of rain. It brings an average of 7 hours of heavy rainfall per year, with a 72% possibility of acid rain. It brings an average of 24 hours of medium rainfall per year, with a 59% possibility of acid rain. It brings an average of 99 hours of light rainfall per year, with a 62% possibility of acid rain.
The Pacific high pressure bring an average rainfall of 60 hours per year, It brings an average of 10 hours of heavy rainfall per year, with a 58% chance of acid rain. It brings an average of 18 hours of medium rainfall per year, with a 36% chance of acid rain. It brings an average of 33 hours of light rainfall per year, with a 30% chance of acid rain.
Southwesterly air currents bring an average rainfall of 51 hours per year, a 9% likelihood of rain. It brings an average of 5 hours of heavy rainfall per year, with a 75% likelihood of acid rain. It brings an average of 12 hours of medium rainfall per year, with a 58% likelihood of acid rain. It brings an average of 34 hours of light rainfall per year, with a 49% likelihood of acid rain.
Air currents from Mainland China bring an average rainfall of 124 hours per year, a 24% probability of rain. It brings an average of 3 hours of heavy rainfall per year, with an 80% probability of acid rain. It brings an average of 17 hours of medium rainfall per year, with a 72% probability of acid rain. It brings an average of 105 hours of light rainfall per year, with a 74% probability of acid rain.
The results of this research have shown that from 2005 to 2018, the chances of acid rain falling has decreased, with the majority of the change coming from light rain. With every air current, the rate of occurrence of acid rain during light rain has had a tendency to decrease. The possibility of acid rainfall during light rain is related to the air quality of the local area. The author surmises that this is related to the Environmental Protection Agency’s amendment of air quality standards in 2012 by integrating the control of PM2.5 figures, causing the air quality in Hualien to improve, thus reducing the chances of acid rain precipitation.
Keywords: acid rain, Backward trajectory, Rainfall patterns, pH value
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