Douglas Thomas A, Sturm Matthew, Simpson William R, Blum Joel D, Alvarez-Aviles Laura, Keeler Gerald J, Perovich Donald K, Biswas Abir, Johnson Kelsey
Cold Regions Research & Engineering Laboratory, Fort Wainwright, Alaska, USA.
Environ Sci Technol. 2008 Mar 1;42(5):1542-51. doi: 10.1021/es070502d.
Mercury is deposited to the Polar Regions during springtime atmospheric mercury depletion events (AMDEs) but the relationship between snow and ice crystal formation and mercury deposition is not well understood. The objective of this investigation was to determine if mercury concentrations were related to the type and formation of snow and ice crystals. On the basis of almost three hundred analyses of samples collected in the Alaskan Arctic, we suggestthat kinetic crystals growing from the vapor phase, including surface hoar, frost flowers, and diamond dust, yield mercury concentrations that are typically 2-10 times higher than that reported for snow deposited during AMDEs (approximately 80 ng/L). Our results show that the crystal type and formation affect the mercury concentration in any given snow sample far more than the AMDE activity prior to snow collection. We present a conceptual model of how snow grain processes including deposition, condensation, reemission, sublimation, and turbulent diffusive uptake influence mercury concentrations in snow and ice. These processes are time dependent and operate collectively to affect the retention and fate of mercury in the cryosphere. The model highlights the importance of the formation and postdeposition crystallographic history of snow or ice crystals in determining the fate and concentration of mercury in the cryosphere.
在春季大气汞消耗事件（AMDEs）期间，汞会沉积到极地地区，但雪和冰晶形成与汞沉积之间的关系尚未得到充分理解。本研究的目的是确定汞浓度是否与雪和冰晶的类型及形成有关。基于对在阿拉斯加北极地区采集的样本进行的近三百次分析，我们认为从气相生长的动力学晶体，包括表面霜、霜花和钻石尘，其汞浓度通常比AMDEs期间沉积的雪（约80纳克/升）所报告的浓度高2至10倍。我们的结果表明，晶体类型和形成对任何给定雪样中汞浓度的影响远大于降雪前的AMDE活动。我们提出了一个概念模型，说明包括沉积、凝结、再排放、升华和湍流扩散吸收在内的雪粒过程如何影响雪和冰中的汞浓度。这些过程是时间依赖性的，共同作用以影响汞在冰冻圈中的滞留和归宿。该模型强调了雪或冰晶的形成及沉积后晶体学历史在确定冰冻圈中汞的归宿和浓度方面的重要性。
