过去千年太阳活动异常期的中国东部旱涝格局

根据过去千年中国东部旱涝等级资料,采用各级旱涝发生几率的比率差指标,参照新近重建的5条过去千年太阳活动序列,重建了其间11个太阳活动异常期的中国东部旱涝格局。结果发现：在11个太阳活动异常期,中国东部旱涝格局各不相同。其中在5个太阳活动极小期（1010-1050年、1280-1350年、1460-1550年、1645-1715年、1795-1823年）,中国东部旱涝格局虽不一致,但长江中下游地区（华北地区）出现偏旱（涝）的几率更高;而在2个太阳活动极大期和4个太阳辐射高值期,中世纪极大（1100-1250年）整个东部多偏旱,1845-1873年的太阳辐射高值期,整个东部多偏涝;其余4个时段（1351-1387年、1593-1612年、1756-1787年、1920-2000年）则旱涝相间出现。集合平均表明：在太阳活动极小期,中国东部呈自南向北的“涝—旱—涝”分布：长江流域偏旱,南北两侧的华南沿海和华北平原偏涝,且西北东部及西南偏旱;而在太阳活动极大期和太阳辐射高值期,长江流域及西北东部多偏涝,华南和华北多偏旱。

Spatial patterns of drought/flood over eastern China in the periods of anomalous solar activity during the past millennium

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, and 4 high solar irradiance periods, were identified. Furthermore, the spatial patterns of drought/flood over eastern China for these 11 periods were reconstructed using an index of difference between drought and flood frequency derived from a 63-site yearly drought/flood grade dataset. It was found that there are different drought/flood patterns over eastern China within 11 solar activity anomalies. Spatial patterns showed alternative distribution of drought and flood 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). In the periods of solar maximum and high solar irradiance, drought prevailed over eastern China in Medieval Maximum (1100-1250), while flood prevailed over eastern China in 1845-1873. The remaining four periods (1351-1387, 1593-1612, 1756-1787, 1920-2000) presented a pattern of alternate drought and flood. 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 the reverse distribution, drought in South China, flood in the middle and lower Yangtze River and drought in most parts of North China, were shown in the ensemble mean patterns of drought/flood for all the 6 periods with solar maximum and high solar irradiance.