探討海洋大陸在不同砍伐程度下的氣候反應

Abstract

本研究旨在了解在海洋大陸地區不同程度的森林砍伐對氣候的反應，包含平均氣候條件對森林砍伐效應的非線性效應、砍伐後的陸地大氣交互作用變化，以及極端溫度、降水特徵等。本研究主要使用地球系统模式進行了五組不同程度的森林砍伐情境模擬，並額外增加一組砍伐實驗來進行砍伐轉折點的敏感性測試，結果顯示，隨著森林砍伐程度的增加，地表溫度和可感熱通量增加，而潛熱通量則減少。降水也表現出非線性特徵，一開始稍微增加，然後隨著森林砍伐的進行而更明顯地增加。然而，非線性效應可能會因島嶼的分佈和地形而有所不同。舉例來說，婆羅洲地區顯示出一個轉折點，而新幾內亞地區則沒有。在陸地大氣交互作用的部分，本研究使用關鍵土壤濕度和分段回歸的概念探討了森林砍伐後陸地大氣交互作用的變化。結果發現陸地大氣交互作用在砍伐後發生了變化，而土壤濕度回饋可能是導致極端氣溫事件頻率增加重要的角色。

This study aims to understand the climate response to varying levels of deforestation in the Maritime Continent (MC), including the nonlinear effects of different degrees of deforestation on average climate conditions, changes in land-atmosphere interactions after deforestation, and the characteristics of extreme temperature and precipitation. Using the Community Earth System Model (CESM), five scenarios of deforestation at different magnitudes were simulated, with an additional sensitivity test to identify the deforestation tipping point. The results show that as deforestation increases, surface temperature and sensible heat flux increase linearly, while latent heat flux decreases linearly. In contrast, precipitation exhibits nonlinear characteristics, initially showing a slight increase and then a more pronounced increase as deforestation progresses. However, the nonlinear effects may vary based on the distribution and terrain of the islands. For instance, a tipping point is observed in the Borneo region, whereas the New Guinea region does not exhibit one. The study explores changes in land-atmosphere interactions after deforestation using the concepts of critical soil moisture and segmented regression. The results indicate that land-atmosphere interactions undergo changes after deforestation, and soil moisture feedback may play a significant role in the increased frequency of extreme temperature events.