Iodine monoxide in the Western Pacific marine boundary layer
Iodine monoxide in the Western Pacific marine boundary layer
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DOI：
10.5194/acp-13-3363-2013
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发表时间：
2013-01-01
影响因子：
6.3
通讯作者：
Platt, U.
中科院分区：
文献类型：
--
作者：
Grossmann, K.;Friess, U.;Platt, U.
本文报道了西太平洋海洋边界层中一氧化碘(IO)的横截面和垂直分布。这些测量是在德国科考船Sonne的TransBrom巡航中使用多轴差分光学吸收光谱(MAX-DOAS)进行的，该船于2009年10月从日本Tomakomai(北纬42度，东经141度)通过西太平洋到达澳大利亚汤斯维尔(东经19度S，146度)。在热带海洋边界层(北纬20度-S 5度)，IO混合比在1~2.2ppt之间变化，而在副热带和中纬度，典型的IO混合比在白天约为1ppt。剖面反演表明，大部分输入输出位于海洋边界层的下部。光化学模拟表明，巡航期间观测到的有机碘前体(CH3I、CH2I2、CH2ClI、CH2BrI)不足以解释所测量的IO混合比。只有在模型中假定了额外的无机碘海气通量(如I-2)时，测量的IO和模拟的IO之间才能达到合理的一致。我们的观察结果进一步证明，活性碘是海洋边界层中的一种重要氧化剂。
A latitudinal cross-section and vertical profiles of iodine monoxide (IO) are reported from the marine boundary layer of the Western Pacific. The measurements were taken using Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) during the TransBrom cruise of the German research vessel Sonne, which led from Tomakomai, Japan (42 degrees N, 141 degrees E) through the Western Pacific to Townsville, Australia (19 degrees S, 146 degrees E) in October 2009. In the marine boundary layer within the tropics (between 20 degrees N and 5 degrees S), IO mixing ratios ranged between 1 and 2.2 ppt, whereas in the subtropics and at mid-latitudes typical IO mixing ratios were around 1 ppt in the daytime. The profile retrieval reveals that the bulk of the IO was located in the lower part of the marine boundary layer. Photochemical simulations indicate that the organic iodine precursors observed during the cruise (CH3I, CH2I2, CH2ClI, CH2BrI) are not sufficient to explain the measured IO mixing ratios. Reasonable agreement between measured and modelled IO can only be achieved if an additional sea-air flux of inorganic iodine (e. g., I-2) is assumed in the model. Our observations add further evidence to previous studies that reactive iodine is an important oxidant in the marine boundary layer.