The influence of regional circulation patterns on wet and dry mineral dust and sea salt deposition over Greenland
The influence of regional circulation patterns on wet and dry mineral dust and sea salt deposition over Greenland
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区域环流模式对格陵兰干湿矿物尘和海盐沉积的影响
DOI：
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发表时间：
2007
期刊：
影响因子：
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通讯作者：
J. Burkhart
中科院分区：
文献类型：
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作者：
M. Hutterli;T. Crueger;H. Fischer;K. K. Andersen;C. Raible;T. Stocker;M. Siggaard;J. McConnell;R. Bales;J. Burkhart
利用格陵兰冰盖(GRIS)不同区域的年分辨冰芯记录，研究了钙(主要来自矿物粉尘)和钠(Na+，主要来自海盐)沉积的时空变化。利用EOF分析对年际变化较大的岩心进行了分组，得到了格陵兰东北部和中部具有区域代表性的钙、钠离子记录。利用ERA-40再分析数据的回归和验证方法，这些共同记录与北美北极、格陵兰和中欧至北欧不同的区域大气环流模式有关。这些模式从杂质的传输和沉积角度进行了解释。在GRIS的东北部，海盐记录反映了东南气流对海洋气团的入侵。这一地区的钙离子变化很大一部分与一种环流模式有关，这表明它是从西方输送和干沉积的。这一模式与目前对沉积在地球表面的尘埃主要来自亚洲的理解是一致的。然而，我们的结果也表明，东北和格陵兰中部沙尘年际变化的很大一部分是由大气沙尘高负荷季节湿沉降的频率和强度决定的，而不是代表亚洲沙尘源和/或远距离输送到格陵兰的变化。由流函数模式解释的区域代理记录的方差足够高，以允许重建相应的区域沉积机制和相关的环流模式。
Annually resolved ice core records from different regions over the Greenland ice sheet (GrIS) are used to investigate the spatial and temporal variability of calcium (Ca2+, mainly from mineral dust) and sodium (Na+, mainly from sea salt) deposition. Cores of high common inter-annual variability are grouped with an EOF analysis, resulting in regionally representative Ca2+ and Na+ records for northeastern and central Greenland. Utilizing a regression and validation method with ERA-40 reanalysis data, these common records are associated with distinct regional atmospheric circulation patterns over the North American Arctic, Greenland, and Central to Northern Europe. These patterns are interpreted in terms of transport and deposition of the impurities. In the northeastern part of the GrIS sea salt records reflect the intrusion of marine air masses from southeasterly flow. A large fraction of the Ca2+ variability in this region is connected to a circulation pattern suggesting transport from the west and dry deposition. This pattern is consistent with the current understanding of a predominantly Asian source of the dust deposited over the GrIS. However, our results also indicate that a significant fraction of the inter-annual dust variability in NE and Central Greenland is determined by the frequency and intensity of wet deposition during the season of high atmospheric dust loading, rather than representing the variability of the Asian dust source and/or long-range transport to Greenland. The variances in the regional proxy records explained by the streamfunction patterns are high enough to permit reconstructions of the corresponding regional deposition regimes and the associated circulation patterns.