fnctId=thesis,fnctNo=367
Exploring the Changes in Mountain Climate in a CO₂-Enriched Warming World
- 작성자
- 기후시스템전공
- 저자
- Pratik Kad
- 발행사항
- 발행일
- 2023-08
- 저널명
- 국문초록
- 영문초록
- The impacts of climate change on Mountains have great concern due to their hydrological, ecological, societal, and geopolitical significance. My study aims to explore the mountain climate change under a CO₂-enriched warming world. Using an integrated approach that combines available reliable climate models, here I investigated the potential changes in temperature and precipitation in the context of global warming. Firstly, I investigate elevation-dependent warming in the Eocene epoch, which refers to mountains warming at higher altitudes due to greenhouse gas effects. The Eocene period, known for high levels of atmospheric CO₂, reflects future climate conditions. However, it is challenging to study mountain regions during this period using proxy data. To overcome this hurdle, I utilized the Community Earth System Model (CESM) version 1.2 to simulate past climate changes available by the Deep-Time Model Intercomparison Project (deepMIP). My analysis of five major mountain ranges revealed a non-linear response of temperature change to CO₂ levels, influenced by seasonal variations through radiative and non-radiative feedback. Based on my findings, mountains will experience overall elevation-dependent cooling in the projected future due to warming at lower elevations. Secondly, assessing hydrological impacts in mountainous regions requires understanding future changes in mountain rainfall. I have researched using available CESM ultra high-resolution (UHR) climate model simulations to understand the effects of rising CO₂ on mountain precipitation. My findings show that the impacts of warming on mountain rainfall are complex and vary depending on the region. Some areas may experience increased precipitation, while others may see a decrease, else combination response. The most significant expected changes are in high-elevation mountains in low-latitude regions with steep slopes. This study is the first to establish a link between changes in mountain precipitation and future greenhouse warming. The analysis emphasizes the importance of feedback mechanisms, specifically the impact of low-level humidity on mountain rainfall and atmospheric convection. These changes have profound implications for mountain systems, such as the changes in water availability, glaciers melting, and shifts in species distributions. Lastly, I have discovered natural variability in the eastern Himalayan monsoon supported by observation, merged products, and reanalysis for the last 43 years. The rainfall in this region is greatly affected by moisture flux convergence, which is associated with the local monsoonal Hadley circulation. Through my research, I have confidently identified how the Himalayan monsoon responds to wet and dry conditions. Moreover, I have found that Monsoon rainfall is a crucial factor in the region's climate, while melting snow does not play a significant role in extreme weather events. Furthermore, Using the Coordinated Regional Climate Downscaling Experiment (CORDEX) model, I have analyzed future projections for South Asia, and the results are indisputable. The result clearly shows that summer monsoon rainfall in the Himalayas will decrease due to increased thermodynamics and reduced dynamics. The decrease in rainfall poses a crucial danger to the communities downstream in the highly populated Himalayan region. It is imperative to take prompt measures to reduce its adverse effects. This study offers an important message about the impact of CO₂ warming on mountain climates worldwide. By providing a thorough evaluation, this assessment helps us gain a better understanding of the intricate connections between the warming effects of greenhouse gases and the climate of mountainous regions. The outcomes of this research will contribute to filling the gap and advancing our understanding of mountain meteorology. The research also provides valuable information on regional climate change impact assessments, adaptation, and mitigation strategies in mountainous regions.
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