Impact of temperature-driven cycling of hydrogen peroxide (H2O2) between air and snow on the planetary boundary layer
Impact of temperature-driven cycling of hydrogen peroxide (H2O2) between air and snow on the planetary boundary layer
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空气和雪之间温度驱动的过氧化氢 (H2O2) 循环对行星边界层的影响
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发表时间：
2001
期刊：
影响因子：
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通讯作者：
R. Bales
中科院分区：
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作者：
M. Hutterli;J. McConnell;R. Stewart;H. Jacobi;R. Bales
过氧化氢（H_2O_2）对大气的氧化能力有重要影响，它决定了大气中痕量物种的寿命。1996年6月，格陵兰岛萨米特积雪区夏季双向H2 O2通量的测量结果显示，白天H2 O2从地表雪库中释放，夜间部分再沉积。观测结果还提供了第一个直接的证据，一个强大的净夏季H2 O2从积雪释放，增强平均边界层H2 O2浓度约7倍，OH和HO 2浓度分别为70%和50%，相对于估计从photochemicalmodeling在没有积雪源。在12天的时间里，H2 O2的总释放量大约为5 × 10（13）个分子m（-2）s（-1），与观测到的顶部雪层的浓度变化相当。光化学和气-雪相互作用模型表明，净积雪释放是由温度诱导的吸收和释放的H2 O2沉积雪，这是相对于冰-气分配过饱和，接近平衡。结果表明，H2 O2和可能的其他挥发性物质的物理循环是理解积雪作为复杂的物理-光化学反应器的关键，并对冰芯记录的解释以及极地地区和积雪附近的光化学具有深远的影响。
Hydrogen peroxide (H2O2) contributes to the atmospheres oxidizing capacity, which determinesthe lifetime of atmospheric trace species. Measured bidirectional summertime H2O2 fluxes fromthe snowpack at Summit, Greenland, in June 1996 reveal a daytime H2O2 release from thesurface snow reservoir and a partial redeposition at night. The observations also provide the firstdirect evidence of a strong net summertime H2O2 release from the snowpack, enhancing averageboundary layer H2O2 concentrations approximately sevenfold and the OH and HO2concentrations by 70% and 50%, respectively, relative to that estimated from photochemicalmodeling in the absence of the snowpack source. The total H2O2 release over a 12-day periodwas of the order of 5 * 10(13) molecules m(-2) s(-1) and compares well with observed concentrationchanges in the top snow layer. Photochemical and air-snow interaction modeling indicate thatthe net snowpack release is driven by temperature-induced uptake and release of H2O2 asdeposited snow, which is supersaturated with respect to ice-air partitioning, approachesequilibrium. The results show that the physical cycling of H2O2 and possibly other volatilespecies is a key to understanding snowpacks as complex physical-photochemical reactors and hasfar reaching implications for the interpretation of ice core records as well as for thephotochemistry in polar regions and in the vicinity of snowpacks in general.