二倍二氧化碳情境下東亞及台灣地區氣候之變遷　第一部份：全球氣候系統模式模擬結果

Climate Changes in the East Asia and Taiwan under 2xCO2 Scenario Part 1: Global climate System Model Simulations

曾仁佑(Ren-You Tzen) ； 林沛練(Pay-Liam Lin)

《環境保護》 27卷1期 (2004/06) Pp. 1-23

https://doi.org/10.30017/EP.200406.0001

摘要

本文主要目的是要探討大氣之二氧化碳(CO2)含量為工業革命前(1870)之值（280ppm，即一倍）時的氣候情境，以及CO2含量達工業革命前之二倍(560ppm)時的氣候情境，進而評估此種氣候情境下台灣地區區域氣候之變遷與對本區氣候衝擊的影響程度。本研究之成果包括兩篇系列之論文，第一部份為使用全球氣候系統模式(NCAR CSM)對不同情境模擬之結果（即本文）；第二部份則為用全球氣候模式之模擬結果，進一步使用地區域氣候模式(MM5)對一倍與二倍CO2含量時之氣候情境做區域氣候變遷之模擬與衝擊影響之評估（下一篇論文）。
經由對NCAR CSM在1XCO2與2XCO2的氣候情境下模擬結果的分析，我們可歸納在二氧化碳濃度加倍（560ppm，約2050年）後，氣候的變化有下列的幾個重點：(1)在東亞地區冬季之極大增溫區位於黃河流域（增溫值高達6.5℃）。而台灣地區由於受海洋的調節增溫較小（介於1~1.5℃間），這與其他模式的模擬結果一致。(2)東亞地區冬季增溫的動力原因為蒙古高壓的減弱，但蒙古高壓的減弱則是受到二氧化碳濃度加倍的影響。(3)台灣附近地區冬季可能會有較多的降水，主要是因為東亞主槽的東移，使得其伴隨之鋒面系統向南偏並且在台灣附近增強，導致降㈬增加。(4)台灣附近地區夏季之降水機會則會減少。這主要是受到太平洋副高向南偏的影響，使得台灣籠罩在高壓氣團內，天氣酷熱。除了零星之午後雷陣雨外，颱風直接侵襲的機會相對的會減少。(5)因為夏季的增溫與颱風降水的減少，台灣地區夏季可能會有嚴重缺水；高溫與缺水將導致電力需求的增加，以致有缺電的疑慮。(6)由於夏季太平洋副高的南移並籠罩在長江中下游地區，使得本區有偏南風及西南風之氣流帶來溫暖之空氣，造成這個地區之增溫特別高。
最後，我們要強調的是，因為目前全世界各個氣候系統模式間對相同氣候情境模擬結果之差異仍相當大，所以NCAR CSM模式的模擬結果可做為氣候變遷的機率和其動力原因推論的參考，但不是唯一之結論。

關鍵字

全球氣候模式 ； 溫室氣體 ； 氣候情境 ； 二倍二氧化碳

並列摘要

This study aims to investigate the regional climate changes and their impact on the East Asia under double CO2 concentration (560ppm) scenario. The results are discussed in two papers. This paper is the first part which discusses the results from a global climate system model (the NCAR CSM) in simulating the influences of different climate scenarios (1xCO2 vs. 2xCO2). Part two using the results from the NCAR CSM simulations to drive a regional climate model (the MM5) and to simulate the impact of these two climate scenarios on the regional climate of the East Asia. The results of MM5 will appear in the next paper.
The results from the NCAR CSM show that when CO2 concentration reaches to double of the pre-industrial era (280 vs. 560ppm) the climate will plausibly have the following changes. First, the maximum temperature increase (up to 6.5℃) in winter in the East Asia is over the Yellow River basin. While the temperature increase is smaller (lie in 1~1.5℃) over Taiwan region due to the modulation of the surrounding oceans. This is in accordance with the results of other models. Second, the dynamic reason for the temperature increase in winter season in East Asia is the weakening of the Mongolia anticyclone. This weakening then is under the influence of the CO2 concentration double. Third, the nearby region in Taiwan may have more winter precipitation because of the eastward shift of the East Asian main trough. The shift of the trough pushes the accompanied frontal system southward and intensifies the frontal system around Taiwan area. Fourth, the chance of precipitation in Taiwan will reduce in summer. This mainly is affected by the southward shift of the Pacific subtropical high. Taiwan is covered by the anticyclonic air mass and the weather is very hot. Therefore, Taiwan may be threatened by the shortage of water and electricity because of the temperature increases and the decreases of typhoon precipitation in summer. Finally, the maximum temperature increase in summer is over the Yangtze River Valley. This results from the ridge of the Pacific subtropical high shifting to this region and bringing in warm southerly flows.
In the end, what we want to emphasize is the results found in this study can provide a valuable reference to estimate the probability of regional climate changes and to deduce the dynamic causes of the changes. However, these are not an exclusive conclusion, since the disparity in the results from other contemporaneous climate system models in the world are still very large.

並列關鍵字

Global climate model ； Green ho use gases ； Climate scenario ； 2xCO2