Spatiotemporal high resolution reconstruction of climatic variation over the eastern Tibetan Plateau during the last 2000 years

本文拟采用多代理分析方法对西藏东北某研究区新采集的树木年轮材料进行分析，除年轮宽度外，还测量了最大晚期木材密度、木材解剖结构和木材中稳定的13C和18O同位素含量。这些参数对不同季节气候要素敏感，能够全面重建过去的气候变率。由于调查地区的气候数据稀缺，将实施区域气候模拟方法。这将为校准气候-树木生长传递函数提供空间上高分辨率的每月估计的地形气候变量（辐射、温度、蒸散发、降水）。模拟工作将包括GCM（统计）降尺度和地形参数化方法的设计和综合实施，以弥合GCM粗分辨率与树木气候分析所需的高分辨率气候变量估计值之间的空间尺度差距。通过重建气压场和由此产生的环流模式，我们希望解开南亚和东亚夏季风在过去重要气候事件中的动态行为。这有助于验证区域气候模式的预测能力，从而更好地预测未来季风强度的区域发展。

We intend to apply a multiproxy analysis approach to newly collected tree-ring material from a study area in north-eastern Tibet: beside ring width, maximum latewood density, wood anatomy and the content of stable 13C and 18O isotopes in the wood shall be measured. These parameters are sensitive to different seasonal climate elements and enable a comprehensive reconstruction of past climate variability. Due to the scarcity of climatic data from the investigation area, a regional climate modelling approach will be implemented. This will provide spatially high resolution monthly estimated topoclimatic variables (radiation, temperature, evapotranspiration, precipitation) for the calibration of climate-tree growth transfer functions. The modelling work will consist of the design and integrated implementation of GCM (statistical) downscaling and terrain parameterization methods to bridge the spatial scale gap between the coarse GCM resolution and the required high-resolution estimates of climate variables relevant for dendroclimatological analyses. By reconstructing air pressure fields and resulting circulation patterns we want to disentangle the dynamic behaviour of the South Asian and the East Asian Summer Monsoons during important past climate episodes. This helps to verify the predictive power of regional climate models to gain better forecast skills for future regional development of monsoon intensity.