Annual regional precipitation variations from a 700 year tree‑ring record in south Tibet, western China
Annual regional precipitation variations from a 700 year tree‑ring record in south Tibet, western China
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DOI：
10.3354/cr01081
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发表时间：
2012-05
期刊：
影响因子：
1.1
通讯作者：
Jingjing Liu;Bao Yang;Kai Huang;D. Sonechkin
中科院分区：
文献类型：
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作者：
Jingjing Liu;Bao Yang;Kai Huang;D. Sonechkin
在藏南朗县两个高海拔地区的中国西部，采集了114株活柏树和死柏树的新测量年轮系列。结合西藏南部以前的两组年轮宽度数据，综合年代学与1961年−2009年期间的仪器降水量有0.563的相关性。年表的低频分量与仪器资料具有较高的相关性，为0.77。基于尺度方法，我们重建了藏南地区公元1300年至2010年的年降水量(7，−，6，6)。1342年−1391、1383−1387、1408−1423、1453−1458、1473−1492、1508−1524、1657−1667、1701−1731、1742−1768、1781−1788、1854−1868、1917−1933和1994−2006年出现了潮湿的天气，而1388年−1407、1424−1452、1459−1472、1493−1507、1525−1656、1668−1700、1732−1741、1769−1780、1789−1853、1869−1916和1934−则是干旱年份。空间相关性分析表明，青藏高原南部的年降水重构包含了一个较强的区域降水信号。通过与附近地区其他基于树木年轮的干旱重建的比较，确定了过去700年来南部TP的相干水分变化。重构序列表明，在过去500年的大部分时间里，南部TP的高(低)降水时段与北部TP的干(湿)时段相对应，这表明西风带和南亚夏季风的不同水汽来源分别对北部TP和南部TP有影响。可能的机制与辐合切变线的移动和北大西洋涛动(NAO)通过西风带控制水汽的遥相关有关。
Newly measured tree-ring series from 114 living and dead cypress Cupressus gigantea were collected from 2 high-elevation sites in the Langxian region in south Tibet, western China. Combined with 2 previous ring-width data sets from southern Tibet, the composite chrono logy correlated at 0.563 with instrumental precipitation over the 1961−2009 period. The lowfrequency component of the chronology shows a higher correlation of 0.77 with instrumental data. We reconstructed the annual precipitation (July−June) from A.D. 1300 to 2010 for southern Tibet based on the scaling method. Wet conditions occurred in 1342−1391, 1383−1387, 1408−1423, 1453−1458, 1473−1492, 1508−1524, 1657−1667, 1701−1731, 1742−1768, 1781−1788, 1854−1868, 1917−1933, and 1994−2006, whereas dry years prevailed during 1388−1407, 1424−1452, 1459− 1472, 1493−1507, 1525−1656, 1668−1700, 1732−1741, 1769−1780, 1789−1853, 1869−1916, and 1934−1993. Spatial correlation revealed that the annual precipitation reconstruction contained a strong regional precipitation signal for the southern Tibetan Plateau (TP). Coherent moisture variations on the southern TP over the past 700 yr were identified by comparison with other tree-ringbased drought reconstructions of the nearby regions. The reconstructed series showed that high (low) precipitation periods on the southern TP corresponded with dry (wet) spells on the northern TP during most of the past 500 yr, suggesting the influence of different moisture sources from the Westerlies and the south Asian summer monsoon on the northern and southern TP, respectively. The possible mechanism was related to the shift of the convergence shear line and a teleconnection of the North Atlantic Oscillation (NAO) through controlling moisture via the Westerlies.