Tree-ring latewood width based July–August SPEI reconstruction in South China since 1888 and its possible connection with ENSO
Tree-ring latewood width based July–August SPEI reconstruction in South China since 1888 and its possible connection with ENSO
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DOI：
10.1007/s13351-017-6096-4
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发表时间：
2017-03
影响因子：
3.2
通讯作者：
Yesi Zhao;Jiangfeng Shi;Shiyuan Shi;Jian Yu;Huayu Lu
中科院分区：
文献类型：
--
作者：
Yesi Zhao;Jiangfeng Shi;Shiyuan Shi;Jian Yu;Huayu Lu
Our understanding of the long-term hydroclimate variations in South China is prohibited by the shortness of meteorological records. Paleoclimatic proxies, such as tree-rings, can be pursued to extend the meteorological records back for centuries to help us better understand hydroclimatic conditions. In this study, we reconstructed the July–August standardized precipitation–evapotranspiration index (SPEIJul–Aug) based on a newly developed 127-yr adjusted latewood width chronology fromTsuga longibracteata, South China. The chronology explained 40% of the actual SPEIJul–Augvariance in the period 1953–2014. The reconstructed SPEIJul–Augcan represent large-scale July–August SPEI variations over South China, including northern Guangxi, Hunan, and Guizhou provinces. From the perspective of the past 127 years, the extreme summer drought in 2013 was not unusual because more extreme drought events occurred in the first half of the 20th century. A significant 2.0–3.6-yr hydroclimatic cycle existed in the reconstruction, which indicated that the SPEIJul–Augmight be driven by El Niño–Southern Oscillation (ENSO). We further checked the time-dependency of the relationship between SPEIJul–Augand ENSO and found that it was unstable. Their relationship was weak before the 1950s, became significant from the 1950s to early 1990s, and then dropped to be weak again and even out of phase since the early 1990s, which may be attributable to the significant westward extension of the western Pacific subtropical high.
