Surface Inorganic Iodine Speciation in the Indian and Southern Oceans from 12o N to 70o S-猫眼课题宝

DOI：

10.1002/essoar.10502894.1

发表时间：

2020-04

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作者：

R. Chance;Tinel Liselotte;A. Sarkar;Alok K. Sinha;A. Mahajan;R. Chacko;P. Sabu;Rajdeep Roy;T. Jickells;David Stevens;Martin Wadley;Lucy J. Carpenter

海洋碘形态已成为初级生产力、沉积输入和海洋氧合的潜在示踪剂。碘化物与海面臭氧的反应也被认为是对流层臭氧最大的沉积汇，也被认为是大气中碘的主要来源。将这些过程准确地纳入大气模型需要更好地了解海气界面的碘化物浓度。对海面碘化物的观测相对较少，尤其是在印度洋盆地。我们展示了在印度洋和南大洋印度区的 3 次航行期间进行的 127 个新的海面（10 m 深度）碘化物和碘酸盐观测结果。观测的纬度从~12oN到~70oS，包括三个不同的水文状况：南印度副热带环流、南大洋和北印度洋，包括孟加拉南部湾。浓度与在其他洋盆的类似纬度观察到的浓度大致相当。海面碘化物的空间分布遵循与其他洋盆相同的总体趋势，碘化物浓度随着纬度的增加（以及海面温度的降低）而趋于降低。然而，这种关系的梯度在印度洋亚热带水域比在大西洋或太平洋更陡，这表明广泛使用的基于海面温度的参数化可能无法准确地表示这种关系。北印度洋热带地区的碘化物浓度比其他地方更高且变化更大。在孟加拉湾遇到了两个极高的碘化物浓度（1241 和 949 nM），这被认为与低氧条件下的沉积输入有关。排除这些异常值，海面碘化物浓度范围为 20 至 250 nM，中位数为 61 nM。海面碘化物控制

Marine iodine speciation has emerged as a potential tracer of primary productivity, sedimentary inputs, and ocean oxygenation. The reaction of iodide with ozone at the sea surface has also been identiﬁed as the largest deposition sink for tropospheric ozone and is also thought to be the dominant source of iodine to the atmosphere. Accurate incorporation of these processes into atmospheric models requires improved understanding of iodide concentrations at the air-sea interface. Observations of sea surface iodide are relatively sparse and are particularly lacking in the Indian Ocean basin. We present 127 new sea surface ([?]10 m depth) iodide and iodate observations made during three cruises in the Indian Ocean and the Indian sector of the Southern Ocean. The observations span latitudes from ˜12oN to ˜70oS, and include three distinct hydrographic regimes: the South Indian subtropical gyre, the Southern Ocean and the northern Indian Ocean including the Southern Bay of Bengal. Concentrations were broadly comparable to those observed at similar latitudes in other ocean basins. The spatial distribution of sea surface iodide follows the same general trends as in other ocean basins, with iodide concentrations tending to decrease with increasing latitude (and decreasing sea surface temperature). However, the gradient of this relationship was steeper in subtropical waters of the Indian Ocean than in the Atlantic or Paciﬁc, suggesting that it might not be accurately represented by widely used parameterisations based on sea surface temperature. Iodide concentrations in the tropical northern Indian Ocean were higher and more variable than elsewhere. Two extremely high iodide concentrations (1241 and 949 nM) were encountered in the Bay of Bengal and are thought to be associated with sedimentary inputs under low oxygen conditions. Excluding these outliers, sea surface iodide concentrations ranged from 20 to 250 nM, with a median of 61 nM. Controls on sea surface iodide

Surface Inorganic Iodine Speciation in the Indian and Southern Oceans from 12o N to 70o S

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