¹⁷O‐excess (Δ¹⁷O = δ¹⁷O − 0.52 × δ¹⁸O) of sulfate trapped in Antarctic ice cores has been proposed as a potential tool for assessing past oxidant chemistry, while insufficient understanding of atmospheric sulfate formation around Antarctica hampers its interpretation. To probe influences of regional specific chemistry, we compared year‐round observations of Δ¹⁷O of non‐sea‐salt sulfate in aerosols (Δ¹⁷O(SO₄²⁻)_nss) at Dome C and Dumont d'Urville, inland and coastal sites in East Antarctica, throughout the year 2011. Although Δ¹⁷O(SO₄²⁻)_nss at both sites showed consistent seasonality with summer minima (∼1.0‰) and winter maxima (∼2.5‰) owing to sunlight‐driven changes in the relative importance of O₃ oxidation to OH and H₂O₂ oxidation, significant intersite differences were observed in austral spring–summer and autumn. The cooccurrence of higher Δ¹⁷O(SO₄²⁻)_nss at inland (2.0‰ ± 0.1‰) than the coastal site (1.2‰ ± 0.1‰) and chemical destruction of methanesulfonate (MS^–) in aerosols at inland during spring–summer (October–December), combined with the first estimated Δ¹⁷O(MS^–) of ∼16‰, implies that MS^– destruction produces sulfate with high Δ¹⁷O(SO₄²⁻)_nss of ∼12‰. If contributing to the known postdepositional decrease of MS^– in snow, this process should also cause a significant postdepositional increase in Δ¹⁷O(SO₄²⁻)_nss over 1‰, that can reconcile the discrepancy between Δ¹⁷O(SO₄²⁻)_nss in the atmosphere and ice. The higher Δ¹⁷O(SO₄²⁻)_nss at the coastal site than inland during autumn (March–May) may be associated with oxidation process involving reactive bromine and/or sea‐salt particles around the coastal region.

中文翻译：

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17O-过度签名印记的南极东部大气硫酸盐形成的区域特征

¹⁷ O型过量（Δ ¹⁷ O =  δ ¹⁷ - Ø0.52× δ ¹⁸硫酸盐O）被困在南极冰核已被提议作为用于过去氧化剂化学评估的潜在工具，而南极洲周围大气硫酸盐形成的理解不足妨碍其解释。探测区域特定化学的影响，我们比较了全年观测Δ ¹⁷在气溶胶硫酸盐非海盐的O（Δ ¹⁷ O（SO ₄ ^2-）_NSS）在圆顶C和迪蒙迪维尔，内陆和在东南极洲海岸遗址，在整个2011年。尽管Δ ¹⁷由于阳光驱动下O ₃氧化对OH和H ₂ O的相对重要性的变化，两个站点的O（SO ₄ ²⁻）_nss均表现出与夏季最低（〜1.0‰）和冬季最高（〜2.5‰）一致的季节性。₂氧化，在春季的南夏和秋季观察到明显的站间差异。的同现度更高Δ ¹⁷ O（SO ₄ ^2-）_NSS在内陆（2.0‰±0.1‰）比沿海站点（1.2‰±0.1‰）和甲磺酸酯（MS的化学破坏^- ）期间在内陆气溶胶弹簧夏季（10月至12月），结合第一个估计的Δ¹⁷ O（MS ^- ）的〜16‰，意味着MS ^-破坏产生硫酸盐具有高Δ ¹⁷ O（SO ₄ ^2-）_NSS的〜12‰。如果有助于MS的已知的沉积后下降^-在雪，这个过程也应该引起在显著沉积后增加Δ ¹⁷ O（SO ₄ ^2-）_NSS超过1‰，可以调和之间的差异Δ ¹⁷ O（SO ₄ ^{2 −}）_nss在大气和冰中。较高的Δ ¹⁷ O（SO ₄ ^2-）秋季（3月至5月），沿海地区比内陆地区的_nss可能与氧化过程有关，该氧化过程涉及沿海地区周围的反应性溴和/或海盐颗粒。