期刊信息
主办:内蒙古农业大学沙漠治理研究所
主管:内蒙古农业大学
ISSN:1003-7578
CN:15-1112/N
语言:中文
周期:月刊
影响因子:1.681818
数据库收录:
北大核心期刊(2004版);北大核心期刊(2008版);北大核心期刊(2011版);北大核心期刊(2014版);北大核心期刊(2017版);农业与生物科学研究中心文摘;中国科学引文数据库(2011-2012);中国科学引文数据库(2013-2014);中国科学引文数据库(2015-2016);中国科学引文数据库(2017-2018);中国科学引文数据库(2019-2020);中文社会科学引文索引-扩展(2008-2009);中文社会科学引文索引-扩展(2012-2013);中文社会科学引文索引-来源(2000-2002);中文社会科学引文索引-来源(2003);中文社会科学引文索引-来源(2004-2005);中文社会科学引文索引-来源(2006-2007);中文社会科学引文索引-来源(2010-2011);中文社会科学引文索引-来源(2014-2016);中文社会科学引文索引-来源(2017-2018);中文社会科学引文索引-来源(2019-2020);日本科学技术振兴机构数据库;中国人文社科核心期刊;期刊分类:资源科学
过去千年中国东部年代际百年尺度干湿变化特征(2)
【作者】网站采编
【关键词】
【摘要】2. Data and methods The PHYDA includes three global variables gridded at a resolution of ~2°and eight climate indices at annual, summer (June—August, JJA),and winter (December—February) tempora
2. Data and methods
The PHYDA includes three global variables gridded at a resolution of ~2°and eight climate indices at annual, summer (June—August, JJA),and winter (December—February) temporal resolutions over the past 2000 years ( Steiger et al., 2018 ). The oラine data assimilation approach was used in the PHYDA by optimally fusing proxy information with the dynamical constraints of climate models. The proxy database includes 2978 annually resolved proxies ( PAGES 2K Consortium, 2017 ;Breitenmoser et al., 2014 ; Steiger et al., 2018 ) and the simulations were run number 10 from the full-forcing ensemble simulations of CESM—LME (CESM—LME10) ( Otto—Bliesner and Brady, 2015 ). By using two skill metrics, the PHYDA data were evaluated against various 20th century instrumental data. The results indicated that the PHYDA data represent well the climate variables of temperature, Palmer drought severity index (PDSI), climate indices, and the location of the ITCZ (Intertropical Convergence Zone). Readers are referred to the supporting information and Steiger et al. (2018) for additional details about the PHYDA. Because few proxy data are available in the early part of the Common Era in the PHYDA, we focus on the hydroclimate variability over eastern China during the last millennium. To investigate its dynamics, we analyze the reconstructed PDSI, near-surface air temperature, the Ni?o3.4(5°S—5°N, 120°—170°W) SST index, the AMO index, and the location of the ITCZ over the Asian—Australian monsoon area (longitudinal range:95°—130°E) in JJA. The area-averaged PDSI and near-surface temperature were calculated using the PHYDA data for the region east of 105°E between 25°and 45°N.
Four independent reconstructions of hydroclimate over eastern China are also analyzed. Two are datasets of the dryness—wetness index (DWI) derived from Chinese historical documents and instrumental measurements, one being a proxy dataset of rainy season precipitation over eastern China from 1470 to 2000 AD ( CNMA, 1981 ; Zhang, 1988 )and the other comprising proxy data of 1500-year time series of regional DWI over eastern China (east of approximately 105°E; 25°—40°N) reconstructed by Zheng et al. (2006) . The third reconstruction is the Monsoon Asia Drought Atlas (MADA; Cook et al., 2010 ), which provides annual tree-ring drought reconstructions on a 2.5°×2.5° gridded network of summer PDSI data, and is also used to provide an investigation of hydroclimate changes over eastern China. Lastly, a composite 2000-year East Asian summer monsoon (EASM) index time series is used, synthesized based on the speleothem δ18O variations from Dongge, Heshang,and Huangye, which can reasonably describe the summer monsoon circulation ( Man, 2012 ).
3. Results
Fig. 1 (a) compares the hydroclimate variation over eastern China between the PHYDA and other proxy records during the last millennium. According to the PDSI series of the PHYDA, the characteristics of the centennial hydroclimate change over eastern China during the last millennium can be highlighted as follows: wet conditions prevail in the Medieval Climate Anomaly (MCA, 1000—1350 AD), followed by a drying trend during the Little Ice Age (LIA, ~1350—1850 AD), and then it was wet again after the 1930s. The comparison shows that similar features are generally observed in the PHYDA and other reconstructions —namely, the drying conditions over the early part of the LIA (1350s—1680s) and the industrial-era wetting. Differences also exist among the reconstructions —most noticeably, the drier period during the 18th—19th centuries (the latter part of the LIA) in the PHYDA is absent in most of the other reconstructions. Another period where the various reconstructions exhibit significant disagreement is during the MCA.
On decadal time scales, we focus on the droughts (see the supporting information for the definition of drought). As shown in Fig. 1 (a),all of the proxy data, including the PHYDA, show more drought events occurred in the early part of the LIA. The PHYDA shows that four severe decadal droughts occurred during this period, and most of them overlapped with the other proxy data —that is, the droughts of 1352—90 AD, 1445—98 AD, 1580—94 AD, and 1626—65 AD. Similar to the centennial hydroclimate change, droughts with the largest differences occurred during two periods, corresponding to the MCA and the 18th—19th centuries. The DWI from Zheng et al. (2006) identified four drought events as having occurred during the MCA, all which except the 1123—47 AD drought could not be observed in the PHYDA and other records. The PHYDA supports the drought of 1123—47 AD, albeit the drought’s duration was much longer. Interestingly, evidence from stalagmite records suggests that most severe flooding occurred over eastern China during this period. In the 18th and 19th centuries, the PHYDA and the treering records reveal several drought events occurred during this period,which could not be identified by speleothem-based paleoclimate record and the DWI.
文章来源:《干旱区资源与环境》 网址: http://www.ghqzyyhjzz.cn/qikandaodu/2021/0714/590.html