- 學位論文
聖嬰／反聖嬰現象下台灣溫度、降雨及空氣污染物濃度變異評析
Variation of ambient environment in association with El Nino/La Nina in Taiwan
摘要
聖嬰-南方濤動現象(El Niño-Southern Oscillation，ENSO) 是一種全球性氣候現象，各國對聖嬰現象於當地氣候影響的研究相當多，但台灣對於這方面的研究卻相當少數。本研究目的為分析ENSO指數在與台灣氣象與空氣污染物變異之相關性，並找出最適合預測之指數。此外，亦評估ENSO事件間接影響台灣空氣品質之情形。本研究分析常見的3種ENSO指數—Niño1+2、指數Niño3.4及指數ONI與台灣不同地區(台北、台中、高雄、恆春、花蓮及台東) 1951-2010年氣象的相關性，並以1980年為中點比較1980年前後事件年與ENSO指數的相關性。使用Gershunov所提出的方法進行計算(反)聖嬰年超過正常年日最大降雨(75百分位)、日最高溫(95百分位)及日最低溫(5百分位)出現頻率進而判斷何種指數對台灣的影響較大。接著用主成分分析 (Principal component analysis，PCA)分析事件年下空氣污染物(PM10、PM2.5、CO、NO、NO2及O3¬)的組成及濃度變化。 結果顯示聖嬰年及反聖嬰年夏季日最高溫以指數ONI的相關性最為顯著，其中，以高雄地區、恆春地區及東部地區，推測東部地區會較為顯著的原因可能為較為接近太平洋。在3個指數所定義下聖嬰年及反聖嬰年冬季日最低溫出現頻率皆小於正常年出現頻率。聖嬰年/反聖嬰年下冬春季日最大降雨量出現頻率皆小於正常年出現頻率。整體而言，台灣地區與指數ONI的相關性較指數Niño 1+2及指數Niño 3.4來的明顯，指數ONI為適合預測台灣未來在聖嬰/反聖嬰下的氣候變化。PCA的結果顯示，聖嬰年下台北地區 (變異係數，coefficient of variation ，CV= 59.01%) 及花蓮地區 (CV= 67.35%) 的主要組成為CO、NO及NO2，台中地區 (CV= 69.20%) 的主要組成為CO、NO、NO2及PM10，高雄地區 (CV= 63.23%) 的主要組成為CO、NO、NO2及PM10。反聖嬰年下台北地區 (CV= 69.20%) 及花蓮地區 (CV= 63.23%) 的主要組成為CO、NO及NO2，台中地區 (CV= 56.79%) 的主要組成為CO、NO、NO2及PM10，高雄地區 (CV= 52.57%) 的主要組成為NO2、PM10及PM2.5。聖嬰年下濃度變化，台北地區以O3增量最多，台中地區、高雄地區及花蓮地區以PM2.5增量最多。反聖嬰年下濃度變化，台北地區以PM2.5增量最多，台中地區以NO2增量最多，高雄地區及花蓮地區以O3增量最多。
並列摘要
El Nino Southern Oscillation (ENSO) is a global climatic phenomenon which occurs frequently in recent years. This study aims to evaluate the relationships between extreme temperatures and precipitation with ENSO indices (Niño1+2, Niño3.4 and The Oceanic Niño Index (ONI)), moreover, to identify the variations of ambient pollutions in association with ENSO events in Taiwan. This study evaluates extreme high temperature (daily maximum temperature) in simmer (from Jun. to Aug.), extreme low temperature (daily minimum temperature) in winter (from Dec. to Feb.), and extreme precipitation (daily rainfall above 75th percentile precipitation) in winter and spring (from Dec. to May) in Taipei, Taichung, Kaohsiung, Hengchun, Hualien and Taitung in association with ENSO events using three ENSO indices (Niño1+2, Niño3.4 and ONI) from YEAR to YEAR. Gershunov’s Law was adopted to identify the variations and frequency of extreme temperatures and precipitation during ENSO and normal years. The variations of concentrations of ambient air pollutants (PM10, PM2.5, CO, NO, NO2 and O3¬) were analyzed using principal component analysis during ENSO years and normal years. The findings show that the extreme high temperature in summer significantly associated with ONI index during El Nino and La Nina years in Kaohsiung, Hengchun, Hualien and Taitung. The frequency of the extreme precipitation in winter and spring, and extreme low temperature in winter were fewer in the normal years than that in El Nino and La Nina years. In general, the occurrences of extreme weather was more related with ONI index than Niño1+2 index and Niño3.4 index in Taiwan. ONI index was more suitable to predict extreme high temperatures in Taiwan. The concentration of O3 was increased in Taipei, and the concentration of PM2.5 was increased in Taichung, Kaohsiung and Hualien during El Nino years. In addition, the concentration of PM2.5 was increased in Taipei, concentration of NO2 was increased in Taichung, and concentration of O3 was elevated in Kaohsiung and Hualien during La Nina years. The PCA analyses show that the main components of air pollutants were CO, NO and NO2 in Taipei with the coefficient of variation (CV) of 59.01%; CO, NO, NO2 and PM10 in Taichung (CV= 69.20%) and Kaohsiung (CV= 63.23%); and CO, NO and NO2 in Hualien (CV= 67.35%) during El Nino years. But, the main components of air pollutants were CO, NO and NO2 in Taipei (CV= 69.20%) and Hualien (CV= 63.23%); CO, NO, NO2 and PM10 in Taichung (CV= 56.79%) ; and NO2, PM10 and PM2.5 in Kaohsiung (CV= 52.57%) during La Nina years. This study observed elevated O3 concentration during El Nino years and increased PM2.5 concentration during La Nina years in Taipei. And observed elevated PM2.5 concentration during El Nino years and increased NO2 concentration during La Nina years in Taichung. And observed elevated PM2.5 concentration during El Nino years and increased O3 concentration during La Nina years in Kaohsiung and Hualien.