Session: Last Millennium & Past2K
Author: Jingyun Zheng / email@example.com / Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographical Sciences and Natural Resources Research, CAS
Co-author: Zhixin Hao, Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographical Sciences and Natural Resources Research, CAS;
Xuezhen Zhang, Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographical Sciences and Natural Resources Research, CAS;
Based on five new reconstructions of solar irradiance, the anomalous solar activity periods during the past millennium, including 5 Solar Minimum periods, 2 Solar Maximum, were identified. Furthermore, the spatial patterns of drought/flood over eastern China for these periods were reconstructed using an index of difference between drought and flood frequency derived from a 63-site yearly drought/flood grade dataset. The simulations from CESM forced by the variation of irradiance under Solar Minimum/Maximum started with initial conditions for different phases of PDO were also performed. The reconstructions show that there are different drought/flood patterns over eastern China among 5 Solar Minimum (1010-1050, 1280-1350, 1460-1550, 1645-1715, 1795-1823), with a higher probability of drought (flood) dominating the middle and lower reaches of the Yangtze River (North China Plain). The ensemble mean patterns of drought/flood for all the 5 Solar Minimum presented a zonal distribution with flood in South China, drought in the middle and lower Yangtze River and flood in most parts of North China. Whereas in the periods of solar maximum, drought prevailed over most of eastern China during Medieval Maximum (1100-1250) and in North China Plain and southwestern China during Modern Maximum (1920-2000) respectively. While the ensemble mean for simulations started with various initial conditions show that drought (flood) prevailed over north (south) of eastern China during Solar Minimum, and flood prevailed over most of eastern China during Solar Maximum. However, the patterns varied with different initial conditions started different phases of PDO, which suggest that the anomalous hydroclimate spatial pattern may be dominated by the internal variability(e.g., phase of PDO) of climate system, rather than abnormal solar irradiance.