Madden-Julian Oscillation (MJO)是熱帶地區氣候次季節尺度的現象，其向東移動之20-80天的振盪可見於深對流與大尺度風場中。過去的研究指出，海洋大陸中複雜的地形與海陸對比等因素對MJO的振幅和東移有極大的影響。21世紀的今天森林砍伐和土地覆蓋變化已經成為一個重要的議題，土地變遷與森林砍伐對區域和全球地表溫度和水文氣候已產生變化。森林砍伐可能會改變環流，水分匯聚以及陸地上的晝夜對流等因素子，極有可能對MJO產生影響。本計畫為探討森林砍伐對氣候次季節尺度的影響的領先研究。本計畫採用更細解析度的氣候模式CAM5-SIT在海洋大陸區域進行極端去森林的設定模擬，探索MC森林砍伐造成的熱力和動力改變對MJO的影響。同時,前期的初期研究結果顯示，海洋大陸的森林砍伐造成大尺度的風場，雲量與水氣的變化，因此本期計畫亦加入探討森林砍伐對南北向水氣傳輸的影響。
The complex land–sea contrast and orography in the Maritime Continent (MC) exerts effects on MJO's amplitude and eastward propagation, known as the MC “barrier-effect”. Circulations, moisture convergence as well as diurnal convections over land, might all be altered by deforestation and have impacts on the MJO. During the past decades, deforestation has become an emerging issue for having both regional and global impacts on surface temperature and hydroclimate. In this project, the subject of the deforestation impact on climate variability is raised. We plan to conduct extreme-deforestation experiments in the MC region using coupled models CAM5-SIT with higher resolution. Thermodynamic and dynamic responses of the MC deforestation and their impacts to MJO will be explored. Further, our primary results from the ongoing project shows that deforestation has altered the large-scale distribution of wind, cloud, and precipitation as well. The impacts on the meridional water vapor transport will be investigated as well in this proposal.
