Study on changes in oxygen isotopes in tree rings in the Yunnan-Myanmar region and the evolution of the southwest monsoon in the past 300 years

Southwest monsoon system is one of the major climate systems of the world, impacting large portions of Asia. However, the evolution history of Southwest monsoon in recent centuries is still controversial. In Southwest monsoon region, the geological records with annual resolution and accurate dating which can record the summer climate information are scarce. Trees are the ideal paleoclimate records with annual resolution and accurate dating, and oxygen isotope in tree ring are influenced by summer moisture condition. The project plans to take tree samples in 3 sites from central Myanmar to northern Yunnan and measure tree ring oxygen isotopes variations in last 300 years, aims to 1) reconstruct summer moisture changes in 3 study areas; 2) clarity the trend of Southwest monsoon during last three centuries; 3) explore variations of Southwest monsoon from the inter-annual to centennial scales; 4) understand how different factors (temperature, volcanic eruptions, El Niño-Southern Oscillation, etc.) affect Southwest monsoon changes. The results of this project would provide important implication for evaluating the possible changes of Southwest monsoon under the background of global warming in the future.