Seasonal variations of snow chemistry at NEEM, Greenland
Seasonal variations of snow chemistry at NEEM, Greenland
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DOI：
10.3189/172756411797252365
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发表时间：
2011
影响因子：
2.9
通讯作者：
T. Kuramoto;K. Goto‐Azuma;M. Hirabayashi;T. Miyake;H. Motoyama;D. Dahl-Jensen;J. Steffensen
中科院分区：
文献类型：
--
作者：
T. Kuramoto;K. Goto‐Azuma;M. Hirabayashi;T. Miyake;H. Motoyama;D. Dahl-Jensen;J. Steffensen
2009年7月，我们在格陵兰岛西北部的NEEM（北格陵兰伊米安冰钻）深冰取芯点进行了一次坑研究。为了研究雪化学的季节变化和钻探场地的特征，我们从一个2 m深的坑壁每隔0.03m采集雪/雪样品，分析它们的电导率、pH、Cl-、NO3 -、SO 42-、CH 3SO 3-（MSA）、Na+、K+、Mg 2+、Ca 2+和水的稳定同位素（δ 18 O和δD）。水的稳定同位素的季节变化明显，这表明在过去的4年里，雪有规律地积累。Na+、Cl-和Mg 2+主要来源于海盐，在冬季至早春达到峰值，而Ca 2+主要来源于矿物尘，在冬末至春季达到峰值，稍晚于Na+、Cl-和Mg 2+。NO3 -浓度呈双峰分布，一个在夏季，另一个在冬春季，而SO 42-浓度则在冬春季达到高峰。冬季到春季的NO3 -和SO 42-浓度似乎受到人为输入的强烈影响。MSA浓度呈双峰分布，一个在春季，另一个在夏末至秋季。我们的研究证实，NEEM深冰芯绝对可以通过计算年层，利用水的稳定同位素和离子的季节变化，在一定的深度。我们计算了2006-08年的年度表面质量平衡。年平均平衡量为176毫米，冬夏和夏冬两季的降水量分别为98毫米和78毫米。在本研究所涵盖的所有三年中，冬夏半年的雪沉积量比夏冬半年的雪沉积量大10- 20毫米。
Abstarct We conducted a pit study in July 2009 at the NEEM (North Greenland Eemian Ice Drilling) deep ice-coring site in northwest Greenland. To examine the seasonal variations of snow chemistry and characteristics of the drill site, we collected snow/firn samples from the wall of a 2 m deep pit at intervals of 0.03 m and analyzed them for electric conductivity, pH, Cl–, NO3 –, SO4 2–, CH3SO3 – (MSA), Na+, K+, Mg2+, Ca2+ and stable isotopes of water (δ18O and δD). Pronounced seasonal variations in the stable isotopes of water were observed, which indicated that the snow had accumulated regularly during the past 4 years. Concentrations of Na+, Cl– and Mg2+, which largely originate from sea salt, peaked in winter to early spring, while Ca2+, which mainly originates from mineral dust, peaked in late winter to spring, slightly later than Na+, Cl– and Mg2+. Concentrations of NO3 – showed double peaks, one in summer and the other in winter to spring, whereas those of SO4 2– peaked in winter to spring. The winter-to-spring concentrations of NO3 – and SO4 2– seem to have been strongly influenced by anthropogenic inputs. Concentrations of MSA showed double peaks, one in spring and the other in late summer to autumn. Our study confirms that the NEEM deep ice core can be absolutely dated to a certain depth by counting annual layers, using the seasonal variations of stable isotopes of water and those of ions. We calculated the annual surface mass balance for the years 2006–08. The mean annual balance was 176 mm w.e., and the balances for winter-to-summer and summer-to-winter halves of the year were 98 and 78 mm, respectively. Snow deposition during the winter-to-summer half of the year was greater than that during the summer-to-winter half by 10–20mm for all three years covered by this study.